Recently, underground utilization is being taken attraction. In the construction of underground structures, space safety, affect to the surrounding areas and low cost are needed to be considered. This study is to clarify the ground behavior around tunnel at each excavation step by using a new three dimensional numerical analysis approach, in which the large deformation and the post failure behavior of soft rock masses can be simulated correctly. Furthermore, the supporting effect of rockbolt on the deformation control for tunnel in soft rock masses is also investigated and discussed theoretically.

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This paper describes a new design method for the reinforced protective umbrella method. In this design method, structural analyses have been carried out by using three-dimensional beam and shell combined model, which consist of not only primary support: steel support and shotcrete, but also auxiliary support: long steel pipe and surrounding grouting. In these analyses, the estimated incremental load is applied to the excavated area behind of tunnel face in top heading and is moved according to the progress of tunnel face. By multiplying the incremental displacements, the total displacements are obtained. Then we discuss the effects of umbrella method for displacement control, according to the analysis results based on this design method.

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The loading test was carried out to examine the interaction between tunnel lining reinforced by steel plate and surrounding soil. Loading device was designed to observe two dimensional behavior of structures. Surrounding soil was simulated by steel rod layer so that it satisfies Mohr-Coulomb failure criteria. Steel rod layer can be set either stiff or soft by side wall supporting condition.
From test results, thin steel plate is sufficient to reinforce damaged tunnel lining under relatively stiff soil condition. Under such stiff soil conditions, vertical load is mainly supported by surrounding soil in case of using flexible thin steel plate and small force is occured in steel plate.

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The objective of this paper is to evaluate the mutual influence of constructing adjacent boxy tunnels in the sandy soil using centrifugal model test. In the case two boxy tunnels are constructed very closely and the lower tunnel of these tunnels is first constructed, it is appeared that the earth pressure acting on the side face of the lower segment goes up about over 120% according to the construction of upper tunnel.

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Techniques for improving seismic safety of urban tunnels have hitherto been limited to those for increasing the flexibility of tunnel structures by applying flexible joints and segments. However, since such techniques are insufficient for ensuring seismic safety of underground lifelines in urban areas when strong earthquakes occur, there has been a demand for developing a new, highly reliable technique, especially for protecting tunnel sections where seismic strain is concentrated locally. Given this situation, an innovative joint research project between the Public Works Research Institute and private companies was commenced to develop a seismic isolation system to be applied to underground structures. This paper will describe results of the joint project, forcusing on the seismic isolation system developed and the design procedure for seismically isolated underground structures.

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We have developed a ductile cast iron segment which is prepared new type structural joints for easy and rapid building of a shield tunnel. Wedge type AS joint between segments and hole-in-anchor type anchor joint between rings made it possible for us to 1 pass building to the tunnel axial direction.
We describe, in this report, about element technology which have developed this time, efficiency evaluation by actual size segments and trial building results in railway tunnel.

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The longer lengths of tunnels call for the need to speed up execution. To do continuously the methods for rapid execution, through simultaneous excavation and segment erection, our solution is to have the segments erected in the shape of a double helix. Single-action joints are used between the rings for rapid execution.
This paper will describe the results from the tests and calculations performed, in order to understand the behavior of the new segments. Through the calculation using data obtained from the test, it was confirmed that there is no functional problem in calculating the helix structure as a ring model.

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Recently, the number of shield tunnel projects which use reinforced concrete tenoned segment has been increased in order to reduce cost and save time. The New Kuwana Cable Tunnel (No.4th Section) is one of the sites which use these segments and this is the first experience in Japan to use the segments for horizontal curved area (radius 130m).The site measurement for longitudinal direction was carried out in order to simulate the tunnel behavior in the curved area. In addition, by using the beam model which has an equivalent longitudinal tunnel stiffness, site measurement results were simulated for the parameter of soil spring element and tunnel stiffness of the model.
In this report, equivalent longitudinal stiffness of the tunnel is proposed in consideration of the effect of the inter-rare materials attached with the tenoned segment.

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This paper presents the method to place an Isolation device on the top of center columns in shield-driven tunnels with multi-circular cross section to reduce shear force and bending moment at the columns and the segments around the connection to the columns. A series of static FEM analyses were conducted to examine the effectiveness of the device, and then it was found that the application of some seismic isolation devices such as rubber bearings to which additional devices to decrease the rotational stiffness was installed, would be practical with a high performance.

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The generation mechanism of shear zone in ground materials under compression is discussed theoretically. Mohr-Coulomb's yield condition and non-associated flow rule are adopted as the constitutive equation in plane strain condition. Stability of soft rock in tri-axial stress condition is analyzed by elastoplastic Finite Element Method. Concentration and dispersion of shear zone are explained by using internal friction angle, dilatancy and confined stress. It is concluded that the generation of shear zone is mainly influenced by dilatancy and confined stress.

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A new water-expansion rubber material of injected type has been developed which can use the impermeability of segment joints. It is practiced in Japan. However, the mechanisms of the impermeability have not been clarified. It is necessary to clarify these mechanisms. As the first step a laboratory impermeability test was conducted by using special permeability test apparatus we have developed. As a result, we have found a mechanism of impermeability by blocking effect. Furthermore the critical impermeability pressure could be expressed by a semi-theoretical equation.

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As launching protection for extraordinarily large diameter shield machine in urban areas, the special anchors have been first introduced in Japan, proving lesser influence to the surrounding ground and the analysis-based execution of the work. The aim of this method is to obtain a monolithic ground condition by installing those anchors vertically and horizontally at the launching portal. The anchor bolts were made from grass fiber which were easily removed by cutter head of the shield machine.
This paper explains the execution plan, monitoring plan and the result of the work, then considers applicability of the anchors as the protection measure for launching the shield machine.

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The Terzaghi's formula has been and is widely used to derive design tunnel pressure in various different conditions. However, with a critical view, the assumptions, concepts, derivation method need to be confirmed with reference to the ways it is applied in current practices. Through several years of experimental and analytical investigation on mechanicsm of tunnel failure and force equilibrium in a limit state, the authors have come to a recognition that the formula might be used in design practices not in the way that it was derived for This paper details on the reasons for this view and addresses such points as should be treated with care to achieve a better definition method of tunnel pressure.

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Cablebolting is a very useful form of support of underground cavern. In practical use of cablebolts, it is necessary to clarify an effect of bond length, properties in analytical design, and so on. In this study, the effect of bond length of fully grouted cablebolts which are plain PC strand and indented PC strand is investigated by laboratory and in-site pull-out tests. To study a determination method of properties (bond strength and bond stiffness) of grouted cablebolt, numerical simulations of pull-out tests are carried out by cablebolt element in FLAC. Experimental results shows that bond strength (pull-out load in unit length) is independent on bond length. On the other hand, bond stiffness (axial stiffness in unit length) is dependent on bond length and effective bond length is similar regardless of each bond lengths. Therefore, we propose the determination method of bond stiffness with effective bond length and its availability is studied by simulations of pull-out test.

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Higashiyama Tunnel, which passes through under the densely residential area, is a twin tunnel excavated in sandy and clayey ground. Due to the limited area available for the construction of a shaft including two tunnels, one tunnel has to commence the excavation using a large cross-sectional connection tunnel from the shaft. In the divergence section, behaviours of the ground and tunnel support are expected to be complicated during the excavation. A numerical simulation using a 3-dimensional Finite Elemental Analysis had been conducted to predict the phenomena likely to occur in the section. The results have revealed that supplementary support is required in this section to ensure the stability of the ground. This paper describes the ground and support behaviours predicted numerically and the economical tunnel supporting design based on the simulation results.

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In the case of shallow tunnel excavation in loose and coarse soils where boulders are present, it is impossible for engineers to gain the deformation parameters of such natural ground from in-site or laboratory tests. Therefore, it is extremely difficult to make an accurate prediction of the deformational behaviour of surrounding ground during excavation. In this paper, the authors model the modulus of elasticity of a hard soil using composite material theory which define as a two-phase material with gravel particles embedded in a sand matrix, and propose a new method in order to estimate the deformation parameters of such natural ground.

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Excavation of underground opening causes a disturbance to the rock around the opening. The damage and re-distributed stress caused by excavation work are supposed to be mainly the fracturing in the vicinity of opening. The damage probably changes the mechanical and hydrogeological properties in the surrounding rock. The degree and extent of the damaged zone is important for the reasonable and safe design, excavation and support of the opening. Seismic refraction survey, P-wave well-logging, Radar reflection survey and ultrasonic welllogging have been carried out to estimate the degree and extent of damaged zone and examine the applicability of these techniques in the newly excavated drifts in the Kamaishi mine. The extent and physical property changes of the damaged zone in the drift excavated by two different methods have been clearly detected by seismic refraction survey.

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TSP (Tunnel seismic prediction) method with elastic wave remains some problems in such case that analyzed results become much different from the actual geological features depending on soil status and/or measuring situation. Although fundamental researches on precision improvement have been done so far, practical procedures for the improvement are not fixed yet.
The purpose of this report is to examine a technique to improve the precision based on measurement data through TSP method.
Around the tunnel that the measurement was done for, there are border faces with three different strikes, which cross the tunnel with acute angles. The measurements were under two kinds of conditions, and examined/ evaluated the precision of measurement by comparing with the actual geological features of the tunnel.

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Elastic wave velocity is useful parameter for rock mass classification, and seismic exploration in tunnel have been applied for rock classification around the tunnel face or wall. TSP method is an exploration technique to predict fault or geological boundary at ahead of tunnel face, and i is able to measure elastic wave velocity around the tunnel.
It was compared elastic wave velocity (Vpt) which measured by TSP with that obtained conventional method, in this study. And it was investigated the relationship between Vpt and rock strength, fissure and thrust power of TBM.
The summary of the result is;
1) It was not clear relation Vpt and rock strength, RMR, but recognized some correlation Vpt and thrust power.
2) The ratio of Vpt to velocity measured tunnel wall is useful to evaluate the stability of tunnel support.

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TSP method is one of the prediction surveys ahead of tunnel face by using seismic wave. This survey has been applied in many tunnels under construction and confirmed its usefulness. The results of this survey relatively correspond to the fracture zone in the survey area.
This paper deals with the potential of geological inference ahead of tunnel face by using TSP survey. For the purpose of progressing in the geological inference reliability, we considered the effective survey range of this survey and the potential of the criteria for the geological inference whether the fracture zone is existed or not.

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On tunnel excavation, It has been important for safety and economy to predict of geological condition of forward tunnel face. In Sekiya-Tunnel, we have excavated the prediction method using drilling energy that is calculated by hydraulic pressure and drilling velocity from exploring drilling.
This paper describes that the forward geological condition is extrapolate from the behavior of drilling energy, and this method is useful the one of data of management of construction.

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Recently, as a construction method for stabilizing cutting face, long facebolt is used frequently for large section tunnels. Under the situation, to define the effect of facebolt and to compose the theory of design, it is necessary to clarify the behavior of facebolt installed in actual tunnel face. This paper shows a few remarkable results of measured axial force of facebolt which is used at three lanes highway tunnel.

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In the construction of twin-bored tunnel, the selection of tunneling method at an early stage is very important. The choices will be among three-drift method, center-drift method, and with no drift method. However, there are no recognized ways of selection yet. In this report, the strengths and weaknesses of those different tunneling methods are compared using FEM analysis as an initial step for establishing the selection procedure.

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Controlled blasting is necessary to restraining ground shake. To reduce the quantity of explosive or to use the one that has slow explosive speed is the effective measure for controlled blasting. We need select the most effective one to consider around conditions.
This time we constructed the road tunnel close by other water-tunnel about 17 meters apart, that was constructed 50 years ago. As controlled blasting we adopted the effective measures, a pilot tunnel by TBM and blasting with electronic delay detonator. The pilot tunnel is effective to reduce explosive shaking energy and the detonator is valid to disperse vibration waves with blasting.
In this report we describe about the result of these measures as controlled blasting.

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Under present conditions that the construction cost by the public investment has been reduced, blasting by ANFO explosive is an effective way for tunnel excavation, because it is low in price. It is difficult to use ANFO explosive in tunneling because it contains such ploblems as blast fume, appearance of ammonia gas in charging and poor water resistance properties. To slove this problem, the adaptability of ANFO explosive in tunnel construction is confirmed by the blasting experiment using the piece ANFO explosive protected by plastic tubes and the coating ANFO explosive mixed with acid. As a result, it is found out that blasting by ANFO explosive is fully effective for tunnel construction with improvement of the above.

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Iwate Tunnel of Tohoku Shinkansen line is a long length tunnel of 25, 810 meters. As usual, it contains such problems as construction environment and cost performance on shotcreting in a tunneling work. In this project, we tried improve mix proportion, mixing method and execution procedure of high quality shotcrete using limestone, silica fume and superplasticizer, for the purpose of improvement on constructability and decrease on the rebound and dust of shotcrete. This report discribes the execution properties of high quality shotcrete obtained from the above experience.

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In the construction of tunnels with a large cross section on the New Tomei-Meishin Expressways, not only safety but also cost reduction should be attained by using new construction method and materials. As an attempt of the development of new materials, we have been studying the fiber reinforced shotcrete (SFRS) which is able to replace steel ribs partly in good ground condition. In this paper, effects as a tunnel support, a calculation method for the bearing capacity and a toughness specification of the SFRS are described.

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In the construction of tunnels with a large and flat cross section on the New Tomei-Meishin Expressways, high-strength concrete is considered to be an expected material for the secondary lining in order to achieve cost reduction by reducing both thickness of the lining and excavation area. For the purpose of finding important points in casting the high-strength concrete and it's strength characteristics with various conditions of casting and mix proportion, we performed testing by using model forms which simulate the real tunnel lining form.

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Recently, high-strength shotcrete (for example, strength of 36N/mm² at an age of 28-days) is used in order to select the most suitable support pattern at highway tunnel constructions in NATM. The authors have applied the high-strength shotcrete to HIDA tunnel in granite for the purpose of reducing design thickness of shotcrete and extending design length of excavation. It is found that it is possible to reduce design thickness of shotcrete and extend design length of excavation in jointed rock, which is better than CL class, by using the high-strength shotcrete from field measurement results and FEM analysis.

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For obtaining the basic data of anchoring behavior of rockbolts, these data were used for revi sing the design manual and quality control manual of the JH (The Japan Highway Public Cor poration), we performed pull-out tests both in laboratory and in-situ for a number of different types of rockbolts, such as high-strength rockbolts, high-tension cablebolts and new materials like carbon fiber or aramid fiber. From the results of these tests, we clarified characteristics of anchoring behavior for the various rockbolts and proposed a new guide line for the quality control of rockbolts.

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Rock bolting are widely and commonly employed to maintain the stability of a tunnel even in soft rock tunnelling. However, little is known about the support effect of rock bolts in soft rocks, although to obtain the quantitative support effects has been an object of study for a long time.
In order to clarify the mechanical behavior and support effect, we have performed loading tests with artificial ground modeled a continuous soft rock, in which various parameters were combined and used. In this paper, we described only the test cases with the parameter of bolt length and longitudinal bolt spacing. As a results, it was clarified that the support effect increased with density of the bolt spacing rather than bolt length if bolts were in the elastic zone.

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A tunnel pre-lining for the restraint of ground deformation has been widely used in tunnel sites around urban areas. In this report, 3-dimensional model tests were carried out to examine the influence of the material and the length of a pre-lining. As a result, the existence of a pre-lining had the restraint effect near tunnel face, especially when the continuous arch-shell was used. As for the range, the effect of 180°over crown was higher than that of 120°. Moreover, no influence of the rest length over face was found, and the restraint effect could be expected if the length of a pre-lining was equal to that of excavation afterwards.

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Icicle and ice sheet formation upon tunnel walls pose a problem for transportation and road maintenance. Heat insulating panels are being developed that can be attached to the walls of existing tunnels to prevent icicle formation. This paper demonstrates the efficiency of these heat insulators through temperature measurements done inward from the tunnel wall. Further, these results generally agree with temperature estimates generated from an equation presented in this paper.

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This report aims at investigating experimentally the reinforcement effects of tunnel linings strengthened with continuous fiber sheet both on loading capacity and deformation performance, at the ultimate limit state.
The fiber sheets were externally bonded to the inside of tunnel lining specimens as inner reinforcement. A vertical loading and a spring units which is considered to model the ground-lining interaction were applied on specimens. The following conclusions are obtained up to this stage of our study:
1) As for carbon fibers, the effect of reinforcement of the high strength type is higher than the ones of high-modules higher type.
2) As for different types of fiber, reinforcement materials, the effect of reinforcement are remarkable by using carbon fiber and aramido fiber but low with fiberglass
3) It has confirmed that the quick hardening adhesives have satisfactory high-level reinforcing effect.

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The mechanical behavior of a tunnel lining is considered by model tests and numerical analyses, and the new design standard of the countermeasures for deformed tunnels is proposed. The design standard is verified by comparing with past designs and the frame analyses which can consider crack propagation. It is found that the standard can propose an appropriate countermeasure corresponding to the degree of deformation of a tunnel and that stiffness, strength and toughness of the reinforced lining increase with reinforcing rank applied in the standard. It can be said that with this standard, the design of the countermeasures of deformed tunnels are able to be done easily and reasonably.

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This report explains about development of the plastic grouting material which is filled into back space of the tunnel lining. In comparison with former materials, the material which is newly developed has realized some special features through mixture of cement and plastic additional materials;(1) separation and dilution by water is decreased, (2) limited grouting is made possible, (3) weight of the material is reduced, (4) handling of the material is simplified.

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The mud pumping action often happens under train vibration beneath track bed concrete of railway tunnels without invert. This phenomenon originates track bed settlement and tunnel lining crack caused by void beneath the track bed concrete, and it becomes a main problem on tunnel maintenance.
This paper shows the method resisting mud pumping under running of trains. In this method, cast-in-place concrete piles with small aperture are executed beneath the track bed of slab track and bear the track bed with the pile as beam structure.

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A part of the Agatsuma Line (East Japan Railway Company) will sink in the Yamba Dam which is being constructed by Ministry of Construction and be rerouted for about 10km. The new line will have three tunnels. We decided to adopt the TBM method due to the medium conditions at the site and surrounding environments for the longest Yamba Tunnel (4.5km).
In the case of Yamba Tunnel, we consider that it is important for high speed excavation and quality keeping to perform detailed geological surveys, modify the TBM and apply an effective support system since the full face TBM method has not been used for railway tunnels in Japan.

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While many TBM tunnels are constructed in recent years. rapid excavation system, seismic prediction ahead of tunnel face and tunnel support system for weak geological features are improved actively. Many long distance tunnels by TBM cannot be excavated smoothly up to now, because rock mass in Japan is complicated and not uniform. But the construction work of Tsukui headrace has completed by using various new technology. This report describes the construction plan and results, and development of the automatic direction control system.

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Excavation data such as the cutter torque and thrust that shows excavation condition in TBM execution, able to be acquired to a real time. Rational tunnel execution is able to be materialized, by establishing an estimation method of face geological condition by using these data. Many research reports such as the selection of the support pattern and estimation of face geological condition that used TBM excavation data heretofore, are observed. However, excavation data change largely by property of rock and degree of crack and degree of fracture etc., the application is in difficult situation.
In this report, it shows the result that carried out analysis about correlation relation between TBM excavation data and geological condition and also stability evaluation point, in an execution case of the rock mass that is composed of many crack andesite and cracking to comparatively a few tuff breccia.

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The DPLEX shield machine, which equips parallel link motion (DPLEX motion) cutter head, can perform tunnel excavation with less toruque.The experiment has been carried out to be applied to DPLEX machine for rock excavation.The following results has been cleared.
(1) The rock excavation performance of eccentric roller cutter is smooth, and the optimum eccentric distance is 20-30% and more to diameter of roller cutter.
(2) The excavation was smooth to be adopted the DPLEX motion by combination with slide motion in vertical plain.

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In conventional spray mortar systems for TBM, liquid type accelerator based on inorganic salts is usually used for the sake of decreasing amount of dust caused by spraying. Using the liquid type accelerator, however, becomes a cause of problems, later strength, durability, and causticity. A new spray mortar system using slurry type accelerator based on calcium sulfo-aluminate is proposed as a solution of problems in conventional systems. In the paper, applicability of the new system and characteristics of the sprayed mortar are verified through field tests. It is concluded that the amount of dust by the system is comparable to that by conventional systems. Additionally, using slurry type accelerator based on calcium sulfo-aluminate is effective to improve the strength increase.

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SIN-OYASHIRAZU tunnel is huge tunnel 5, 229m long. On the huge tunnel, the work environment gets bad, as evidenced by increaseing the dump truck and air leaking of ventilation ducts. Therefore, excessive ventilation equipment becomes necessary, and a construction fee rises to secure a good working environment. As for this tunnel, a rational ventilation form was examined, long ventiletion ducts and a container system were adopted as a result of the examination. This report about the examination of the rational ventilation form and the result.

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To design optimal tunnel supports, the load acting on supports have to be evaluated. In this study, the value of the load to deform the support accordant with the result of displacement data in tunnel fields was calculated. The results were acquired as follows:(1) depth of overburden is approximately proportionate to the load acting on the support in the ground behaving as continuum, (2) the load is nearly constant in some grounds with deterioration and openness of cracks reported by face observation, but there may be a large difference between the load with irregular geological conditions.

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It is difficult to survey the geology along a tunnel in advance precisely, so it needs to change the tunnel support pattern evaluating the ground condition during excavation. In this report, some in-situ tests such as seismic prospecting, schmidt hammer test, point load test and so on were carried out at the tunnel face to evaluate the ground condition quantitatively. As a result, we can confirm that elastic wave velocity has relation to the dgree of crack and weathering of the rock and could become an index to adopt the auxiliary method. Moreover, the measured value of schmidt hammer test and point load test have relation to the compressive strength of rock and could become an index to change the tunnel support pattern and adopt the auxiliary method.

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Standard tunnel support patterns have been modified at highway tunnel construction sites to be adapted for the real conditions of a rock mass. To apply the modified tunnel support patterns effectively, it is important to establish rock mass classification system and relationship between rock mass quality and tunnel support patterns. Since there has no standard method for observation and evaluation of rock mass at a tunnel face so far, we proposed a new rock mass classification system which was invented by analyzing a database of highway tunnels statistically. This paper presents it's application to highway tunnels.

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It is extremely important for engineers to select suitable excavation machinery in the early stages of a project in which rock excavation is considered. Therefore, the prediction of bulldozer ripper production from geological data has been carried out. But, in the case of shaft excavation in soil and rock masses, there is no good way to estimate excavatability. In this paper, the authors propose a new method to assess shaft excavatability by the use of EI (Excavatability Index). EI is defined by conventional RQD using drill cores and RQD obtained by observing the corresponding borehole wall. And its validation for engineering applications is demonstrated.

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In recent years, it is often the case that a new tunnel is constructed or a housing site is developed in the vicinity or just above an existing tunnel. It requires precise estimation of the influence of the construction work on the tunnel in service.
The authors mentioned about a case of open cut excavation above an existing tunnel in soft ground, and to show the characteristics of deformation and other behaviors of the tunnel based on the measurement results.
The authors then carried out 2-D FEM analysis while to know how to decide the section for analysis and determine input parameters of the ground. Based on the vertical displacement of the tunnel obtained, the authors analyzed the distribution of vertical displacement in the longitudinal direction using a beams model placed on an elastic floor to discuss the stability of existing tunnel and the safety of train operation and evaluate the applicability of the analysis results with measurements.
This paper reports the results of the study.

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A questionnaire investigation was executed to make difference by occupation on selection of auxiliary methods clear in this report. The questionnaire investigation used an actual weak rock tunnel construction as questions. And it asked validity of auxiliary method as answers from each point of view of safety, economical, easiness, reliability, and whole construction. 101 people from clients, site and design engineers filled out the questionnaire. That result were analyzed statistically and showed tendency of engineers decision.

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A series of centrifuge model test is carried out for investigating the cutting face stability of vertical shield tunneling in cohesive soil ground. Test results show that shear stresses near cutting face ground are increased as a slurry pressure at the cutting face of a tunnel is decreased and the cutting face ground collapse when the induced shear stresses exceed an undrained shear strength of the cutting ground. Based on test data, a relation of overburden pressures against failure pressures at the cutting faces of vertical tunnels is studied. From the obtained relationship, required slurry pressure for the cutting face stability can be determined.

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