The huge tsunami generated by the 2011 Tohoku earthquake more than M9.0, causing serious damages, was beyond our experiences and much larger than the estimated one in Tohoku region, Japan. The inundation area of the 2011 Tohoku at many areas in coastal area exceeds those on the hazard map based on the assessment with historical evidences in Japan, causing more casualties in the 2011. The people tried to evacuate toward outside of estimated inundation area but the tsunami trapped them. The experiences among survivors including the traffic condition along the coast as well as the information of casualty by local government are compiled to find out the situation of evacuation process and the solutions to save our lives at that period, which should be shared as the lessons learnt are for disaster risk reduction in future to make resilient city. The numerical model of evacuation using the multi agent for pedestrian car interaction has been applied for the planning in the target area. Moreover the tsunami widely observed and recorded on the affected area were no longer sea water but muddy one with strong current containing sediments near shore and on the land, changing the topography; erosion and depositions along the coast. The debris such as parts of houses, infrastructures, plant, woods, cars and ships moved by tsunami currents are new target in the tsunami simulation. Therefore, we make great efforts on developing the new integrated simulation of tsunamis with multi scenario and complex feature including sedimentation on the coast. Fragility analysis of tsunami characteristic such as tsunami inundation height, flow depth or velocity against human fatality, damage on building, fishery boat, pine tree and pedestrian bridge are also carried out and is going to be included on.

The Cambridge Giken collaborative research was started in 1994, based on the strong awareness of Mr. Akio Kitamura, President of Giken, Ltd., on the issues related to construction. Every summer two students stay in Kochi, Japan, to carry out field and model tests using press-in machines and other experimental facilities in Giken, so that they can learn this technology by experience. This paper introduces an outline of the summer projects conducted in Kochi each year, and summarizes some research findings on the performance of a pressed-in pile the estimation of subsurface information from piling data and the performance of a sheet pile wall.

Conventionally, steel sheet piles have been utilized as earth pressure resisting structures such as riverbank revetments, seawalls, road retaining walls and temporary retaining walls by taking advantage of their excellent horizontal resistance characteristics. In recent years, it is also applied to structures expected for vertical bearing capacity. The "closed-end steel sheet pile", which is expected to exhibit a higher vertical bearing capacity, has been developed by providing a processed and closed cross section of the front end portion of the steel sheet pile. In the Sheet Pile Foundation Method, it has been shown by previous studies that effective reinforcement of substructures can be achieved by using this processed “closed-end steel sheet pile”. However, the bearing capacity characteristics when the “closed-end steel sheet pile” is supported on the intermediate layer is unknown. Therefore, in order to grasp the bearing capacity characteristics when the “closed-end steel sheet pile” was supported on the intermediate layer with SPT N value of about 30, the full-scale load test was carried out. As a result, from the distribution of the axial force and the peripheral resistance, the resistance of the pile-end closed-section zone is sufficiently demonstrated, and it is estimated that the plug of the pile-end closed-section contributes greatly to the bearing capacity development.

Piles have been used widely on commercial developments in London for about the last 60 years. The life of a commercial building is about 25 – 30 years and as each building is demolished and rebuilt, the piles from the previous buildings remain in the ground. These cause obstructions to the new foundations because removal is difficult, time-consuming and expensive. Published research has shown that sheet piled foundations are a genuine and viable alternative to cast in-situ concrete piles. Individual sheet piles have relatively low capacity when axially loaded, therefore it is necessary to consider their use as a pile group in conjunction with a pilecap. In this paper these are defined as hybrid foundations. An increase in bearing capacity was observed when the geometry of the sheet pile group was varied from a circular arrangement to square formation. This research aimed to understand the influence of the geometric shape and the dimensions of sheet pile groups on their bearing capacity.

A Steel pile sheet pile (SPSP) foundation on a viaduct construction site was designed and constructed using the press-in method combined with inner excavation. After driving the pile, the press-in method combined with inner excavation was not able to drive the piles into the ground to the required depth, so the press-in with water jetting method was adopted after considering environmental impact, economy, and work schedule. With the press-in with water jetting method, the pile was driven to the required penetration depth while water was pumped under high pressure through pipes internally attached to the pile. The press-in with water jetting method was selected as a piling method for the steel pipe sheet pile foundation which is adjacent to a river, a highway, and houses in a confined space. There has been no recommended bearing capacity formula for press-in with water jetting method in Japanese design specifications for highway bridges, so the information of the vertical resistance characteristics (end-bearing capacity, skin friction) and lateral resistance characteristics (modulus of horizontal subgrade reaction) of the foundation was determined by a loading test to obtain the properties of foundation after changing the pile driving method. Using chemical grouting to increase the ultimate bearing capacity is also discussed. According to the results of vertical loading test and horizontal loading test after ground improvement, the ultimate bearing capacity was confirmed to be greater than the designed value for Level 2 earthquake. The stress in the piles was confirmed to be smaller than the allowable value both for Level 1 and Level 2 earthquake. The Ste el pipe sheet pile foundation using the press-in with water jetting method combined with the grouting method had full structural abilities for Pier structures.

A reinforcing method for a surface circular foundation with a thin flexible underground structure, called “sleeve”, is proposed in this paper. The sleeve wraps soil cylinder underneath a surface circular foundation to confine lateral movements of the soil cylinder. This constraint increases lateral confining pressure, which improves shear strength and stiffness of the soil cylinder underneath the circular foundation. Consequently, the bearing capacity of the surface circular foundation increases and reaches that of massive conventional embedded foundations. In this paper, a series of loading tests of model footings on model sand was conducted to investigate the effects of reinforcement with a sleeve structure. The circular model foundation was made of aluminium with a diameter of 30 mm. A sleeve structure with dimensions of 40 mm in diameter and 30 mm in height was made from a thin polyethylene terephthalate film with a thickness of 0.1 mm. Comparisons of performances of foundations between embedded foundations and surface foundation with sleeve were made and the advantages of surface foundation with sleeve are discussed. The results showed that the surface foundation of 1.5 m in diameter with sleeve provided similar values of bearing capacity obtained from a conventional massive foundation embedded at 1.5 m in prototype scale.

2 segments precast concrete piles consist have been applied as foundations for “Cargo Transportation Route for of the north-eastern part of the Caspian Sea North Caspian Marine channel with berthing facilities Cargo Offloading Facility” (CaTRO, COF) the “Prorva” oilfield, Atyrau region in the Caspian Sea Coastal Area, Western Kazakhstan during November 2016 to July of 2017. This paper presents that seven characteristics engineering-geological elements (units) are identified based on the geological setting and the borehole logs. Testing of soils by piles was submitted by engineers of the LLP “KGS-Astana”. The main purpose of this paper is to present many aspects of foundation construction in low temperature condition and freezing soil in winter season, to analyze the bearing capacity and a settlement of low temperature -5℃, -10℃. Pile testing was carried out in winter, when local climate and soil condition make is a 1 m. depth frozen soil make impact to the changing a ratio of ultimate bearing capacity and settlement. At the construction site of Seaport ''Prorva" the static compression load test method was applied. In practice, SCLT is one of the widely used methods for analyzing of pile bearing capacity. This paper presents the result of the analysis of 2 joint concrete piles of number (d/36), (k/3). SCLT testing was holding on 2 cycles.

Deep water piled clusters and structures supported by large mono-piles are designed to take up significant lateral and pressing loads. In particular, it relates to offshore structures whose foundations need long piled supports of high bearing capacity. Correspondingly one meets high level of stresses and significant deformations in such constructions. It is especially important for port or offshore engineering to avoid environmental problems caused by traditional pile driving technologies. From this point of view, the Press-in Method is the most appropriate approach. Two improved structures and technologies have been worked out to optimize stress-strain state of such piled clusters and mooring/fender dolphins. (1) Developed is an effective and less resource-demanding design when connection of all pipe piles with large diameter steel casing provides their joint work and favorable distribution of stresses and deformations in pile clusters. It is foreseen that both casing and pipes are installed by pressing into bottom soil. (2) To increase energy-absorbing capacity of mooring/fender dolphins, a new design of combined tubular mono-pile structure was worked out and researched. It incorporates internal flexible pile and damping element (cushion) placed between external and internal piles’ heads. For both innovative and patented solutions, laboratory tests and numerical modeling were fulfilled and compared.

Development of an effective countermeasure for the existing bridge foundations subjected to the influence of riverbed excavation in Thailand is the main objective of this study. Due to the riverbed soil excavation for the utilization in construction works for many years, the levels of riverbed have been considerably decreased, resulting in reduction of embedded lengths of piles for bridge foundations. The reductions of pile embedment lengths, in other words, reductions of bearing capacity due to the lowering of riverbed soil is the main cause of bridge pile foundation settlements or collapses at present. In order to prevent the damages of existing bridge pile foundations caused by riverbed soil excavation, a reinforcement method using sheet piles called “Sheet Pile Wall (SPW) reinforcement” is proposed in this paper. The proposed SPW reinforcement method consists of 2 simple steps without new additional piles or any modifications of existing structures. Firstly, sheet piles are constructed surrounding the existing problematic bridge pile foundation. Secondly, the empty space inside the SPW is filled with sand or other porous materials such as crushed concrete. In order to investigate the performance of the proposed SPW reinforcement method, series of load tests on the small sized model single pile and model 4-pile pile foundation were carried out. The experimental results show that the proposed SPW reinforcement method is very efficient and promising.

Integral abutment bridges are becoming popular because the elastomeric bearings are eliminated, which can reduce the construction and maintenance costs. However, the girder displacement due to environmental thermal forces is directly cope by the pile foundation which can increase the pile stresses and bending moment significantly. Pre-bored pile foundation system can be used to improve the pile flexibility using a pre-bored hole that is filled with elastic materials, but the behaviour of soil-pile interaction on this system is still rarely explained. In this study, the effectiveness of filler material properties such as soil grain size and density were examined to reduce the pile cracking possibility effectively. An experimental study will be performed using single pile model test. The behaviour of ground soil and filler material due to cyclic lateral loading was performed using macro-scale testing to evaluate the effectiveness of this system. Results were presented in the form of cyclic load-displacement curves and normalized bending moment charts against pile depth and cycle time for each soil properties. The appropriate filler properties and dimension of this system are expected to reduce the bending moment along the pile due to lateral displacement loading which can solve the problem on the integral abutment bridge foundation.

A spiral pile is a useful pile because it has high resistance against vertical load such as push-in and pull-out loading, but it also has a problem that its horizontal resistance is relatively small, comparing to a steel pipe pile with the same diameter. In addition, the conventional design has the following problems; 1) unifying effect of the surrounding ground by the revolving press-in has not been considered for safety design, 2) evaluation method for bearing capacity against combined load is not established, and 3) inclination effect of loading has not been clarified. In the previous research (Isobe and Yamauchi, 2017), a simple method is proposed to consider the unifying effect of the surrounding ground due to the revolving press-in, based on the various loading test results such as push-in, pull-out and lateral loading tests for the spiral piles in soft clay ground. Then, the bearing capacity of the spiral pile subjected to combined load was investigated with the numerical analysis method. In this paper, in order to verify this analysis, model tests have been carried out in which model piles were revolving press-in a dry silica sandy ground and then loaded at some arbitrary angles.

In this paper, the results of static horizontal loading tests of steel tubular piles installed by the Gyropress Method and the Press-in Method assisted with water jetting were collected, and the se horizontal bearing performance s were evaluated. As a result, the following were drawn: 1) Load-displacement curves of the Press-in Method assisted with water jetting and the Gyropress Method were consistent with the Weibull distribution curve, when the deformation index m=1.0. The average yield displacement normalized by the pile diameter with the Gyro Method is consistent with the average values of 4.1 – 4.5 % for steel tubular piles installed by other construction methods, and that with the WJ Method gives smaller value than the average of other construction methods; 2) The coefficient of horizontal subgrade reaction calculated backward from the displacement at the loading point showed somewhat larger value than the design value when the reference displacement was set at 1 % of the pile diameter in the case of the Gyro method. On the other hand, for cases constructed by the WJ method, the average of measured kH is regarded fairly consistent with designed kH, but the variation of them are large; and 3) In the case of group piles, δg - kH curves were better fitted than δg / B - kH curves. The calculated backward kH approximately coincides with the design kH when the horizontal displacement at the ground surface is about 15mm.

This paper discusses the influence of embedment depth and embedded medium on the behaviour of laterally loaded large diameter steel tubular piles with relatively large moment loads based on centrifuge model tests under cyclic lateral loading. Embedded media tested were Toyoura sands with 80% and 95% relative densities, and a soft sand rock. From the loading tests, two failure modes of the pile foundation were observed, i.e., ground failure and pile structural failure depending on the embedment depth and ground strength. Due to the large moment load and rigidity in the embedded portion, the latter failure mode tends to dominate in hard mediums. For the pile with relatively small embedment depth, the increase of embedment depth can increase the lateral and moment resistance. However, as the embedment depth increases, the effect of the depth becomes less significant, especially for ultimate resistance due to the pile structural failure. “Optimum embedment depths” over which the increase of horizontal resistance becomes less are, depending on the initial lateral stiffness and ultimate bearing capacity, shallower for that of the stiffness than the ultimate bearing capacity. From the abovementioned observations, it was confirmed that the determination of the rational embedment depth considering given conditions is the most critical step in the design of this type of pile foundation.

Five centrifuge model tests are reported in this paper, which discusses the overall behaviours of self-standing stiff sheet pile walls embedded in soft rocks. Two different soft rocks, namely sand rock and mud rock were modelled by using sand-cement-clay mixtures at appropriate mixing ratios. In this study, a centrifuge modelling technique has been developed in which the loading process can be simulated from design conditions to the ultimate failure conditions on an embedded wall in soft rock. A series of centrifuge tests has been carried out to investigate the influence of embedment depth on the stability of self-standing steel pipe sheet pile walls. Experimental observations reveal that, the stiff sheet pile walls suffer from rigid body rotations about a pivot point. An equilibrium analysis was performed by switching the active and passive zones based on the observed pivot point at the verge of rotational failure. A similar contribution of increment in embedment depth on the stability of walls can be confirmed from the analysis and experimental outcomes. Also, it can be confirmed that the wall can stand in the design condition with a reasonable safety margin with a relatively small embedment depth compared to current design practices and a small increment in embedment depth e.g., 0.5m, can significantly increase the wall stability and prevent the wall from ultimate collapse.

Steel pipe pile walls are utilized for many projects. Recently, the application of the walls has increased especially for high walls. In such a case, the pile diameter should be larger in order to gain high flexural rigidity and the embedded ground should be stiff enough to satisfy the requirement for the wall displacement. A conventional method such as Chang’s formula has been used in the design of such high walls, but several difficulties in design and construction are arising due to the natures of larger diameter pile. With respect to the design issues, the embedment of the walls determined by the conventional method becomes longer beyond necessity for stability, since the higher flexural rigidity of larger diameter of piles is one of the critical conditions for the minimum embedment depth. In case of harder ground conditions, the longer embedment is likely to lead to difficulties in installing piles and hereby causes extra construction time and cost. In this paper the behavior of wall with large-diameter steel pipe piles embedded into a soft rock is investigated by a simple analysis using a beam-spring model targeting the wall embedment length as the main parameter. The calculated results were compared with those observed in centrifuge models. The results of this study suggest that the conventional method could require unnecessary embedment length and then the calculation model with Elasto-Plastic soil springs can determine more rational embedment length even if the larger diameter piles are used for retaining walls into stiff layers.

Due to the performance improvement of construction machines and the increase in case studies in mountainous areas, cases have increased where the pile foundation is supported by a bedrock as a bearing layer. In a rock layer that is thought suitable as a load bearing foundation because of its high strength and high deformation modulus compared with those in general ground, it is considered that the embedded length into rock could be shortened if a rational design method were established. Consequently, the existing knowledge and guidelines are sorted out in this paper, focusing on the characteristics of rock mass, modelling of horizontal bearing capacity characteristics of foundations, and the behavior of short piles subjected to lateral loading, for extracting issues arising when proposing cantilevered steel tubular pile retaining walls with shortened embedded length in a relatively stiff rock layer. At the end, issues arising at a time of making the embedded length shorter in a rock layer will be described.

The equi-distantly pressed-in self-standing steel tubular pile retaining walls (hereinafter referred to as steel tubular wall(s)) are column row structures. They are often adopted where the construction yard is limited and when the construction schedule is tight, since they can be installed in smaller construction yards, compared with other structures such as gravity type walls and those with inverted T-type footings. The Press-in Method is suitable for space-saving constructions, and the applications of self-standing steel tubular walls with high stiffness are increasing, since a rotary cutting press-in machine that can press-in large diameter steel tubular piles has recently been developed, enabling its application of the method to taller walls. This paper presents an overview of the design methods of the self-standing steel tubular walls, along with the site conditions, surrounding environments and the details and reasons for their adoptions in the 3 projects where self-standing steel tubular walls with high stiffness were used. The walls are generally designed using a beam expressed by a linear spring element on a floor that can be regarded elastic in semi-infinite domain, following the guidelines and manuals for other structure types (e.g. Advanced Construction Technology Center, 2006 ; IPA, 2017). With the increase in diameter, secondary moment of inertia and stiffness of steel tubular piles tend to become larger, consequently to make the embedded length longer Three case studies presented here are all for road retaining walls, and they clarified the construction constraints such as limited construction yard, construction in stiff ground and limited construction time. The features of the wall structures and advantages in the press-in operation together with the points of attention are addressed through these case studies sorting out the future issues thereby.

The mechanical advantage of cylindrical underground structures against external forces has been known to many engineers. A cylindrical structure reinforced by intermediate ring beams with hat-shape steel sheet piles as an outer shell is not an exception. However, more discussions are required regarding the behavior study and the design methods at the time of earthquake, since similar structures and their case studies are scarce. With these backgrounds, stresses and acceleration exerted in main structural members have been measured since 2009 under ordinary and seismic conditions, installing measuring instruments inside the structures, and the following points were verified; 1) Based on the acceleration obtained from the actual measurements on structures at the time of the Great East Japan Earthquake (2011), the seismic acceleration waves for a layer equivalent to technical reference base were calculated by means of the ground response analysis. As a result, it was verified that the simulated waves were consistent with the measured results, and that the behavior of the underground structure was in harmony with that of the ground; and 2) Conducting a dynamic analysis based on the seismic acceleration waves calculated in 1), it was verified that the underground structure had a sufficient resistant capacity against an earthquake.

J-WALL II is a construction method that uses steel sheet piles (product name: Beetle pile) as a temporary retaining wall, then integrates them with the reinforced concrete part after ground excavation to construct a composite underground wall. Here, "Beetle pile" is a new steel sheet pile formed by joining T-shaped steel and fixing a reinforcing bar to a hat-type steel sheet pile. A T-shaped steel and a fixing reinforcing bar function as a shear connector when joining the temporary retaining wall and the reinforced concrete part. Main features of J-WALL II are as follows. 1) Saving construction space and shortening construction period. 2) Favorable for construction in a narrow space. 3) Composite wall having excellent structural performance. In order to confirm the performance of the J-WALL II construction method, we conducted following investigations. (1) It was confirmed that there was no difference in press-in resistance and construction speed compared with the conventional hat-type steel sheet piles by the installation test of new steel sheet piles for a composite wall "Beetle pile" by the Silent Pillar (Press-in Method). (2) Strength of the shear connector part of J-WALL II was confirmed by a punching shear test between the "Beetle pile" and the reinforced concrete part. And we built the design method of the shear connector part. (3) By a bending test of the actual J-WALL II structural member, we confirmed that the wall body can be designed as an integral wall structure (complete composite wall) up to the ultimate limit state.

After the Alaska Earthquake and the Niigata Earthquake in 1964, many researches have been conducted on the liquefaction and its caused damage. In the 2011 Great East Japan Earthquake, liquefaction of sandy ground was observed in wide areas. The authors have built a large-soil tank for the experiment to develop effective liquefaction countermeasures. The soil box can cause and keep the liquefaction continuously by injecting the water flow from the bottom of the model ground. This paper introduces this experimental apparatus and reports one of the test results on the behaviour of the oil tanks during liquefaction and the effectiveness of the measures by using sheet pile walls.

In the Great East Japan Earthquake of 2011, many river embankments were damaged by strong seismic waves. After the earthquake, tsunami spilled over damaged embankments. In the river levee, back covering coatings were damaged due to settlement of fill by the earthquake motions or liquefaction, and back covering coatings and fill soils flowed out backrush. As a reinforcement method for river banks, a construction method of placing sheet piles in the embankment wall body is being studied for the purpose of maintaining the function of the levee at the time of an earthquake or flood. The occurrence of the Nankai Trough earthquake is expected in Kochi Prefecture, and the prefecture is proceeding with countermeasures under the idea of triple protection. Especially reinforcement of river embankments is an important issue in disaster prevention and reduction. In the past, with respect to various reinforcement methods in river embankment, dynamic centrifugal model experiments and behavior by effective stress method are being verified. In this study, we conducted a model experiment of double wall sheet piles on shoulder of cut-off wall method. In addition, model experiments were also conducted on a floating structure that keeps embedded depth of sheet piles in the liquefaction layer and shorten embedded depth for the purpose of cost rationalization of the present construction method. Furthermore, the relationship with the dominant period of the earthquake was also investigated for these experiments.

In order to improve the effectiveness of steel sheet-pile method for the countermeasure on soft ground settlement under embankment load, a PFS method was developed under the research group whose chair was Prof. Ochiai of Professor Emeritus at Kyushu University, Japan in 2005. At that moment, a series of in-situ full scale tests for this countermeasure method including PFS method which is the combination of end bearing sheet-pile with those of floating type were conducted in the City of Kumamoto, Japan under the Ministry of Construction (current name of this ministry is Ministry of Land, Infrastructure, Transportation and Tourism).

In this paper, the main objective is to discuss the quantitative evaluation of PFS method using coupling finite element analysis. Because of the geometry of PFS structures, this analysis was conducted in three dimensions. A numerical analysis was done for the cases of the full scale tests at the site in Kumamoto City, in which the field tests with the case of PFS method was conducted. A “tij model” developed by Nakai et al which can be considered the effect of intermediate principal stress was used as a constitutive model for clayey soil. Here, not only displacements in the ground but also the change of excess pore water pressure were compared.

Finally, based on those numerical studies, an effectiveness of PFS method as a countermeasure method was discussed.

A steel sheet pile is used as a settlement countermeasure method for levees on soft ground. It is expected that settlement of landside ground can be suppressed by penetrating steel sheet piles nearby toe of slope of the levee. In order to improve the performance of existing two methods, full bottom landing and floating method, the Partial Floating Sheet-pile method (PFS method) was proposed. However, the PFS method has a limited number of experimental studies and construction examples. Thus, the effect of the PFS method is not well-understood. In this study, a 1/50 scale ground models with levees and two types of sheet pile walls were built and self-weight consolidation experiments were conducted with and without the countermeasure using centrifuge apparatus. The objective was to confirm the effect of the PFS method on the settlement of landside ground and failure mode of the levees. The experimental results showed that the countermeasure cases suppressed the settlement of landside ground more than the non-countermeasure case. It was observed from image analyses that in the countermeasure cases, relative displacement of clay layer occurred near sheet piles. Continuous shear strain induced by relative displacement is considered to cause cracks on the slopes of the levees.

The steel sheet pile reinforcement method is often used as a countermeasure against settlement and lateral displacement when constructing embankments on soft ground. However, it has been reported that during Kumamoto earthquake (2016), some of the sheet piles that had been installed since the construction of the embankments contributed to seismic resistance, although they were not intended as an earthquake countermeasure. Therefore, by assessing the seismic performance of the steel sheet pile method, it is also expected to expand the applicable range of the construction method. In this study, a numerical investigation on the effect of the steel sheet pile reinforcement method with different embedment lengths was conducted against dynamic loading due to earthquakes, as well as the effect of settlement and lateral displacement at the time of static loading due to embankment construction. Numerical results indicate that the steel sheet pile reinforcement method enables us to obtain not only the isolated effect for the deformation during embankment construction, but also the aseismic effect by securing the proper embedment depth.

In recent years, the steel sheet piling method is used as a countermeasure against soft ground for the purpose of reducing the subsidence of the surrounding ground and lateral displacement. Among them, the partial floating steel sheet piling method (called “the PFS method”) constructs a stress blocking wall by alternately placing short-length floating steel sheet piles and long-length conventional steel sheet piles, and is a new construction method to decrease settlement of the embankment side. In addition, it is possible to decrease the subsidence of the ground around the embankment, and it is excellent in terms of workability and economy. This method has been applied as a subsidence countermeasure for river embankments in Kumamoto Prefecture, Japan. However, in April 2016, a massive earthquake occurred in Kumamoto prefecture that recorded a maximum magnitude of 7.3, causing damage such as subsidence in the embankment of the rivers in Kumamoto plain where the PFS method was used. From these backgrounds, the objective of this paper is to report the damage of river embankment caused by the 2016 Kumamoto earthquake and to evaluate the effectiveness of steel sheet pile structure including the PFS method as an earthquake countermeasure.

This paper presents case histories of the instability of clay deposits beneath a loose sand layer induced after the Great East Japan Earthquake in 2011. As a reactive countermeasure against damage of this kind, the upper parts of existing river dykes were removed. Subsequently, sheet piles were installed immediately after the earthquake at the toes of river dykes to separate the influences of dyke instability on adjacent residences. Thereafter, the river dykes were returned to their respective original heights by surcharging the fills for dykes. To confirm the effects of those countermeasures, numerical analyses were conducted, combining both the computer codes for dynamic analysis of behavior during earthquakes with the code for static analysis of post-earthquake behavior. Results of numerical analyses agree well with variations of measurements of settlement with the elapsed time. Results indicate that the reactive countermeasures adopted herein work well for reducing the instability of river dykes and residences caused by the great earthquake.

In order to reduce liquefaction damage to river levees, remedial stiff zones are constructed below toes of levees to restrain lateral flow deformation of liquefied foundation soil under the levee. Sheet piling, among other ground improving techniques, is preferably employed especially in urban areas where houses are existing close to levees and workspace is limited. Settlement of levee becomes smaller if sheet piles with a higher flexural stiffness are used. However, it is often the case that settlement does not satisfy the design criteria even if steel pipe sheet-piles with very high stiffness are used. In this study, an innovative countermeasure method using sheet piles is proposed. In the proposed method, the horizontal earth pressure is enhanced with the help of elastic nature of sheet piles. This is achieved by inserting a wedge along the sheet piles to the levee side which deforms laterally the soil below the levee, increases horizontal earth pressures and reduce the liquefaction susceptibility. The effectiveness of introducing additional horizontal stress, hereafter termed as pre-stress in this study, was examined through centrifuge tests. In the tests, the amount of the horizontal stress increase and the affected zone were confirmed by conducting cone penetration tests at multiple locations before and after application of the pre-stress. Dynamic centrifuge tests were carried out on models with and without the pre-stress. It was found that the cone tip resistance increased not only in the vicinity of the sheet pile but at almost everywhere in the soil beneath a levee. Settlement of the levee decreased with increasing the introduced pre-stress, confirming the effectiveness of the method.

In the Great East Japan Earthquake in 2011, many tide barriers and breakwaters collapsed due to the tsunami. On the other hand, one structure consisting of double sheet pile walls remained almost undamaged. This paper introduces a newly developed experimental apparatus called ‘Tsunami Simulator’, in which two types of tsunami, surge and reflux, can be simulated to investigate into the behavior of structures a part of which is embedded in the ground. It also summarizes the result of the adequately scaled model test on the behaviors of gravity-type and pile-type levees, when they are hit by surge-type tsunami. The test results showed that the pile-type levee remained resilient to tsunami while the gravity-type levee failed by sliding. This result demonstrates the effectiveness of the use of piles to improve the resilience of structures. On the other hand, the specification of piles should be adequately determined in design to assure the resilience of the system. It would be reasonable to allow some plastic deformation of piles, which cannot be adequately scaled in the model test, especially when a huge tsunami has to be considered.

In the near future, there is fear that coastal dykes will sink by liquefaction due to a large earthquake such as Nankai Trough Earthquake. To overcome the potential damage, the application of double sheet-piles with partition walls to coastal dyke has been proposed. The partition wall is installed perpendicular to the double sheet-piles with a certain interval. Authors confirmed that this structure should be effective in reducing the settlement of coastal dyke on liquefied ground through the model tests. To propose a design method for the double sheet-piles with partition walls countermeasure, the authors carried out 2-D numerical analyses (code:LIQCA2D15) based on the model tests. As a result, good reproducibility of dyke behaviour such as settlement, sheet-pile deformation and excess pore water pressure could be confirmed. However, the applicability of numerical analyses was only discussed in 2-D framework. Therefore, in this study, authors discussed the 3-D behaviour of this structure using 3-D numerical analyses (code:LIQCA3D15). It was found that the wider the interval of partition walls becomes, the larger the bending deformation of sheet piles as well as the settlement of coastal dyke itself become.

The 2011 Tōhoku earthquake and Tsunami event devastated large parts of the Japanese coastline, causing widespread damage to infrastructure and claiming many human lives. The dual row wall concept is potentially a robust and efficient sea wall design. However, loss of soil strength and stiffness from earthquake induced liquefaction is a prospective design concern. Evaluating the resilience of the dual row system to earthquake loading is a complicated soil structure interaction problem even when the walls are founded in dry ground. Further, soil liquefaction fundamentally changes the seismic wall and soil response. Centrifuge modelling provides an avenue to explore the dynamic behaviour. Dynamic testing of small scale centrifuge models of the dual row wall systems, founded in dry and liquefiable sands is detailed. Recorded wall and soil accelerations are considered and the impact of excess pore pressure generation on the shear stress transmission highlighted. Observable changes in the dynamic shear stress strain behaviour of the soil rationalise the system responses. A modified approach to inferring the wall displacements from the accelerations and discrete displacement measurements is discussed. Consistency between the results is verified and the differing displacement modes obtained are considered in the context of the overall soil behaviour.

After the 2011 off the Pacific coast of Tohoku Earthquake, for existing coastal levees, performance-based seismic designs have been carried out to counter this level II earthquake with a Tsunami, and earthquake resistance measures are being implemented in preparation for The Nankai Trough earthquake which is expected to occur at 70% probability in the next 30 years. In this research, as earthquake countermeasures for the coastal levee against liquefaction of the foundation ground during the earthquake by the press-in type steel pile, setting of the required performance at the time of earthquake, examination of performance-based seismic design and countermeasure construction study were carried out. First, we estimated the extent of damage by the numerical analysis method that the levees suffered with inertia force and ground liquefaction accompanying the earthquake, then we found out the necessity for earthquake resistance measures with the levees according to the performance requirements. In this paper, we mainly describe difference in calculated behavior of the levee due to analytical modeling methods about components of the coastal levee such as sands embankment, wave-dissipating block and concrete revetment. In addition, we show effects of press-in type steel pile as earthquake countermeasures by the numerical analysis method.

The coastal areas of the Pacific Ocean suffered extensive damage by the tsunami of the 2011 off the Pacific Coast of Tohoku Earthquake. Then, there are needs to develop reinforcement methods of existing caisson type breakwaters against tsunami force. Installing a row of piles behind the caisson with backfilling the space between the caisson and piles with rubbles is proposed as one of the reinforcing methods against tsunami. In order to establish the design method of this reinforcing method, the design of the steel pile is the most important. For designing steel piles, it is necessary to estimate the load acting on them from the caisson side. Here, a series of model loading experiments were conducted. The experimental results suggested that the external force acts on the pile only in the ground at the initial stage of loading and it was found that the external forces acting on the piles dominate in the vicinity of the backfilling part by gradually compressing the backfilling part by displacement of the caisson.

The 2011 Tōhoku earthquake and tsunami brought into question the adequacy of the pre-existing shallow foundation seawall design due to the large number of failures recorded. A new type of seawall made of adjoining large, jacked-in, steel pipe piles embedded 10-15m into the ground is currently installed along the Kochi coastline. Seawall design against tsunamis is a unique, true ULS design, which presently is carried out using codes of practice not specifically tailored for this scenario. Through small scale wave flume experiments and lateral loading tests of single piles at full-scale the adequacy of current design methodology as well as the efficiency of the new steel pile seawall design is assessed. It is found that current Japanese codes, although designed for tsunami shelters, provide appropriate predictions of wave force for the case of seawalls needing to withstand overtopping waves. The lateral pile tests highlight the current codes’ accuracy in predicting pile stiffness and bending moment profile. Remaining shortcomings, such as no provision in current seawall design for the effects of soil softening during tsunamis, are evinced. Even so, steel pile walls seem an effective seawall solution due to their high embedment and capacity to dissipate wave energy through yielding.

The Great East Japan Earthquake has implied the big potential all over Japan for earthquakes with magnitude 9.0. In the Great East Japan Earthquake, ports and fishing ports played an important role in (1) transportation of emergency supplies after the earthquake, (2) early recovery of marine products lifting and distribution functions. Kochi Prefecture has approximately 713 km coastal-line on which 88 fishing ports are scattered and 46,000 people live in this area. The fishing ports are very important as the life base of local populace for the relief activity, restoration-reconstruction and business continuity plan. The fishing ports are desired to maintain function when subject to the earthquake motion and tsunami of the Nankai Earthquake. In Kochi Prefecture, not only major ports but also fishing ports are proposed to be used as earthquake resistant quay walls in the event of a disaster. This research was executed for the Kaminokae Fishing Village, which is a typical district of the local fishing port in Kochi Prefecture. In the preparation of the earthquake resistant wharf, low construction cost and a short construction term would be anticipated. One of the effective methods for the economical construction of an earthquake resistant wharf is the adoption of the press-in pile.

This paper presents an idea of a new method to improve stability of geo structures against shear failures due to service loads, seismic loads, heavy rainfalls, etc. In this method, a series of short piles, like steel bars or sheet piles, are pressed-in to the depth of the failure surface, which is considered to have the lowest safety factor in the design process And they are left underground by decoupling from the rod used for press-in process. As the piles are arranged only around the failure surface, the total amount of piles is much smaller resulting in cost effective improvement of stability of the geo structures. In this study, the effects of the underground short piles are examined by simple models of under ground section along the failure surface, using dry silica sand and rigid steel piles. The models were sheared under a direct shear condition with constant surcharge, and their shear stress and displacement, as well as the rotation of the short piles, were observed.

End-resistance type earth anchors are often employed to reinforce slopes or to ensure slope stability. Hulk Earth anchor developed by Anchoring Rope and Rigging Pty Ltd (AR+R) in Australia is one of flip-type end earth anchors (hereafter, flip anchor). The flip anchor is installed in the ground by driving or press-in. When the flip anchor is installed in the ground, the end plate is closed to facilitate the penetration process. When pull-out force is applied to the anchor through pulling rod or wire, it is expected that the end plate is opened with increasing the pull-out displacement to enhance the pull-out resistance. At present, pull-out resistance mechanism of the flip anchors has not been fully understood. Hence, in this research, fundamental push-in and pull-out experiments were carried out to investigate performance of the flip anchors in dry sand model ground. Furthermore, push-up experiments of a trap door in a dry sand model ground simulating an anchor were carried out to investigate the mechanism of the resistance of the anchor in plane strain condition. An image analysis of the ground deformation was conducted in this series of the experiments. A simple model of the ground failure was used to obtain theoretical values of the pull-out resistance of the anchor.

This project arose from collaborative research between the University of Cambridge and Giken Ltd. The primary aim of the project was to investigate the mechanics of water-jetting as an aid to press-in piling in sandy soils using controlled site testing carried out in Kochi, Japan. The experimental work was followed by analysis of the data collected, and the data analysis was complimented by a finite element model made using ABAQUS. The main findings of the research are that the rate of pile installation is heavily dependent on the jet pressure used, and that high and low jet pressures induce two different mechanisms.

The data shows that plugging within the sheet pile causes a build up of resistance at the base of the pile, preventing further penetration of the pile and causing the pile to 'stick', until enough water pressure has built up at the pile base to allow the plug to be destroyed. At this point, the pile appears to 'slip' into the soil, and the process repeats. The high water pressures are able to build up around the pile even in relatively permeable soils due to crushing of sand particles at the base of the pile forming an impermeable film.

In this research, penetration resistance and load-settlement relations of a pile installed by jack-in, surging and vibratory were investigated through model tests in dry or saturated sand grounds. An open-ended aluminum pipe having a length L of 597 mm, an outer diameter Do of 32.0 mm and an inner diameter Di of 29.3 mm was used for the model pile. The model pile was instrumented with axial strain gauges at 5 cross-sections to obtain axial forces in the pile. The model ground was dry or saturated silica sand in a cylindrical container having a diameter of 566 mm and a height of 540 mm. Relative densities Dr of the dry and saturated grounds were 80% and 70%, respectively. In the case of the saturated ground, 7 pore water pressure transducers were buried in the model ground at different depths and different horizontal distances from the pile. In each experiment, the model pile was first installed into the model ground by jack in or surging or vibratory to a depth of about 400 mm. After the installation process, a static load test (SLT) was carried out, in order to compare the load settlement behaviours of the pile installed by the three different methods.

The first part of the paper sets the actual scientific task to develop the integrated piling process aimed at the automated construction of pile foundations and sheet pile walls for civil and industrial buildings/structures. The technology is based on the application of the Modular Aggregative Piling System (EC Transzvuk), intended for pressing into the ground precast pile elements by a flow-production method with the highest possible performance at the lowest cost of labor. High productivity of piling works is provided by non-stop operation of the equipment, due to the integrity of the basic non-interruptible automated process: pile installation – piling machine displacement. The second part of the paper considers some recent innovations of piling technologies developed to simplify tubular piles press-in installation by prevention of the soil plug formation. One of the proposed approaches uses separate (step-by-step) driving of pile tip (shoe) and pile shaft concentrating energy of pile driving machine on tip or on shaft. Another approach is based on alternate driving of tubular pile and internal core avoiding formation of soil plug at the pile tip.

The Press-in Method is a pile construction method in which a pile is statically pressed-in by holding the reaction piles. With the method, it is possible to reduce noise and vibration that usually emanate in conventional pile installations, and to shorten the construction period of temporary works. This construction method is widely adopted especially in urban areas for this advantage. In addition, piles can be installed into hard ground by the Press-in Method assisted with augering, or by the Press-in Method assisted with rotary cutting. The application range of the Press-in Method is spreading more and more. In the Press-in Method, construction data such as time, depth, press-in force and torque can be automatically and continuously recorded, and are used e.g., in construction management.

Using the construction data collected from the three methods (the standard Press-in Method, the Press-in Method assisted with augering and the Press-in Method assisted with rotary cutting), IPA(2017) has compiled methods of estimating ground information at the location of the pile toe. In this paper, validity of the estimation methods was examined, estimating ground information by the three methods with the construction data obtained in the field, and comparing it with the already given ground information. In addition, demonstrated was possibility of extending construction conditions that constitute premise for the application of the estimation methods.

Screw piles offer several potential benefits for deployment offshore for renewable energy developments. They are easy to install, have the potential to achieve large capacity and generate low noise and vibration during installation. This latter benefit makes them an attractive alternative to driven piles where there are concerns over the impact of installation on marine mammals. Although screw piles are attractive for offshore deployment, their recent use has been limited to small piles therefore, to allow offshore deployment considerable upscaling of these piles must occur. This increase in size comes with concerns of how they will perform and the requirements for installation. For example, it is well known that the shaft capacity of a driven pile is influenced by plugging or coring behaviour internally. As screw piles are installed by rotation and vertical force, it is necessary to investigate how this installation process effects pile plugging behaviour. As part of a preliminary study, the effect of rotation on plugging and installation capacity behaviour was investigated by 1g small scale model testing in sand. The addition of rotation during installation was seen to give a significant reduction in the pile penetration resistance in both open and closed ended piles

The shaft friction of displacement piles in sand depends on the change in the horizontal stresses on the pile shaft during installation. Recent research has revealed that the sectional shape of a pile has a strong influence on the horizontal stresses, leading to great difference of the pile shaft friction. Based on these findings, an optimization idea has been proposed, referred to as the “switched-on mechanism”. The main emphasis in this paper is given to understanding the changes in horizontal stresses measured during “switching-on” from open-section (installation individually) to closed (load testing for whole pile walls) in cross section. In order to model the construction and load test process for pile walls, a dual installation system was installed into the beam centrifuge. This paper discusses the stress changes through the whole construction process and the efficiency of the switched-on mechanism, and highlights how physical modelling has allowed this highly complex problem to be quantified.

Nowadays deep embedded and large diameter steel pipe piles have been widely used in Japanese port facilities for supporting large vertical load, as growing sizes or changing structural types of port facilities. Estimation for bearing capacity of large diameter and deep embedded piles has been complex problems such that bearing capacity is increased because of deep embedment and plugging effect is decreased because of using large diameter piles. To investigate the inner friction force mechanism development with soil plugging of open-ended piles was the main aim of this study. In this research, open-ended piles with different pile outer diameters were penetrated into dry sand. The plugging situation in the model pile penetration experiment was evaluated from two viewpoints of the plugging phenomenon. As a result, it was found that if the ratio of the wall thickness to the pile diameter is the same, there is not much difference in the degree of plugging due to the pile diameter.

The cone penetration test is a proven method for evaluating soil properties, yet relatively little research has been conducted to understand penetrometer readings (CPT-data) as a complicated boundary value problem. The interpretation of CPT-data tends to rely on empirical relationships, many of which have been developed over the years for soil identification and classification. Those studies tend to have an implicit expectation that the relationship between the CPT-data and a single soil parameter is independent, e.g. the friction angle can be estimated directly from CPT-data without the need to consider any boundary value problems. In this study, a series of numerical analysis by using FEM (GEOASIA) was conducted to demonstrate the complexity of the penetration mechanism. A description of the calculation procedures is first provided with some preliminary calculation results with various displacement ratios at the supposed cone apex. The results highlight the differences in the resistances at the cone tip even when the friction angle is the same and are evidence of the complexity of the penetration problem.

In this paper, influence of installation of new piles on an existing buried pipe was investigated through small-scale model tests. Close-ended aluminum pipes of 595 mm in length and 32.0 mm in outer diameter were used for the model piles in dry sand model ground. A close-ended PVC pipe of 700 mm in length and 18.0 mm in outer diameter was used as a buried pipe model. The PVC pipe was instrumented with axial strain gauges to obtain bending moments in vertical and horizontal directions. The PVC pipe was set in the model ground horizontally at a depth 230 mm. The model piles were pressed-in into the ground from the ground surface at locations near the buried pipe. The distributions of the buried pipe displacements in the vertical and horizontal directions were estimated using the measured bending moments. The experiments were carried out in dense (relative density Dr = 80%) and loose (Dr = 50%) sand grounds. The paper presents the experimental results, and discusses the influential factors, such as distance between the piles and the buried pipe, the pile tip level and soil density, on the deformation of the buried pipe.

Construction works in urban areas must satisfy not only the safety of a newly constructed structure itself but also the safety of existing structures adjacent to the new one. Visual observation might be a first step to understand the interaction of a newly constructed structure and existing structures adjacent to new one, if a soil would be visible. Recently, Ezzein and Bathurst (2011) reinvented a transparent soil for laboratory modelling. This technique is fundamental and versatile for geotechnical model testing. The principle of a transparent soil is to match the refractive indices of transparent grains and pore-liquid. There have been many combinations of grain-materials and pore-liquids proposed (Ganiyu et al., 2016). However, though the principle is simple and straight-forward, there seems to be a plenty of know-hows which should be mastered and established to conduct laboratory model tests with transparent soils. In this article, the authors would like to present such procedural know-hows and the application of them for some demonstrative experiments.

Press-in 3D FEM analyses were carried out to examine the behavior of a buried gas pipe and the soil ground during the press-in installation of a sheet pile. The displacement of a buried gas pipe was set as the parameter to investigate the gas pipe behavior. In the first analytical model, both of the sheet pile and the gas pipe were modeled as rectangular solid structures and the horizontal distances between a sheet pile and a buried gas pipe were arranged in 100mm, 200mm, 500mm and 1000mm. In the second model, not only the rectangular shape but also a standardized shape (SP-3) based on the real model was made as a sheet pile. In addition, 6 series of modeling were prepared in terms of the setting direction of the SP-3 sheet pile and the horizontal direction between the sheet pile and the gas pipe. In order to clarify the behavior of the inside ground, strain contour diagrams were shown in addition to the displacement of the gas pipe. Through these two types of analyses, the effect of the press-in installation to underground structures was discussed.

The objective of this project is to install steel tubular piles used as a temporary earth retaining wall as well as the main wall for an open cut structure by the Gyropress Method, because the ground was stiff, and there were some areas where the ground surface was uneven, and the piling work had to be conducted adjacent to residential houses. Among the technical challenges, the construction adjacent to residential houses was severe, only 1.5 m away at the closest location. One countermeasure was taken so as to prevent objects from being scattered over the residential houses, and the piling operation was carefully conducted within the allowable noise and vibration level. In spite of another countermeasure taken, slurry overflowed from the steel tubular pile, due to the stiff ground of shale layer that was prone to plugging. It was likely that the construction would be delayed, and dust would be scattered. As a measure, pre-cutting piles and a specially fabricated jig were used, and it was fortunately possible to solve the problem. In addition, vibration and noise never went over the maximum required value, and the construction was completed without any complaint. This paper introduces this construction case.

This paper describes a renovation work of the old Kaishin Bridge over a class-I Nishiyoke River in Kitanoda, Higashi-ku, Sakai, Osaka. The project was ordered by the Civil Engineering Office of Tondabayashi, Osaka. The site was near the station with a heavy traffic of vehicles and pedestrians, and the work had to be done adjacent to residential houses on both the sides of the river. Since steel sheet piles were used as a temporary earth retaining wall to remove an old weir and build a new abutment, the Press-in method with water jetting was selected at the design stage. However, the soil boring log showed the maximum SPT N-value is over 50, indicating that it might be impossible to press-in piles. Furthermore, there were possibilities that the sludge might flow into the river and the surrounding ground would be affected. Hence, the Hard Ground Press-in Method was selected instead, after the design change. The whole construction process including the pull out works of steel sheet piles was completed by us, the prime contractor, Fujii Co., Ltd.

Earth retaining walls for foundation works in urban area are often constructed under conditions where there are buildings and underground structures in the neighbouring areas. These items will become the key factors in a selection of proper construction method. Due to these backgrounds, cases have lately been seen where the earth retaining walls constructed of steel tubular piles installed by the Gyropress Method are adopted in urban area. The method can penetrate not only stiff grounds, but also underground obstructions. It is possible to largely reduce construction period, since the earth retaining walls can be constructed only by press-in operation without removing underground obstructions in advance. In addition, it is possible to construct walls even in narrow sites where enough working space cannot be secured, since the press-in operation is conducted with self-walking on top of the already installed piles. The constructions can be implemented with low vibration and low noise, keeping the effect on the surrounding environment to a minimum. In this paper, with such advantages of the Gyropress Method as described above, introduced are the cases where steel tubular earth retaining walls for foundation works constructed by the Gyropress Method are adopted in urban area.