This study investigates the possibility of utilizing the waste rock powder as a supplemental material for cement stabilization of soft clay ground. The results of the study are summarized as follows: (1) there is an optimum mixing proportion of the waste rock powder for the cement stabilization, (2) the unconfined compressive strength varies in inverse to the ratio of designed water content to cement content, (3) the unconfined compressive strength has the highest value in every case when the waste rock powder and cement are mixed with the soft clay at a designed water content around 1.2 times the plastic limit, (4) the corresponding content of waste rock powder and cement can be estimated upon the previously selected value of designed water content, (5) the optimum content of waste rock powder and cement can be decided for various values of the water content of clay using the experimental equations.

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At present, the Great Sphinx as one of the most important World Heritages is being seriously subjected to a remarkable weathering and deterioration. Aiming at contributing to the restortion work for the Great Sphinx, authors are carrying out site investigation in order to clarify water budget between the bedrock and the air where weathering and deterioration are taking parts. In this paper, the application of the electrical prospecting (resistivity method) was illustrated. As a result, the distribution and the daily cyclic change of the moisture in the bedrock were confirmed by monitoring the electric resistivity of the rock at the site.

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The researches of contaminants' behaviors in unsaturated soils are important to remove the contaminants effectively. A series of column tests was conducted to understand the mechanisms for seepage and gas diffusion behaviors of volatile organic compounds (VOCs) in unsaturated soils. The result of seepage tests yielded that pemeability of VOCs in loam, which has high warter-holding capacity, is strongly affected by degree of water saturation, but less affected in silica sand and Toyoura sand. Besides, gas diffusion tests indicated that diffusion coefficients of VOCs gas differ in the various kinds of speciments even they are prepared at a same porosity.

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Since the movement of soil particles and aggregates in compaction practice is hindered by the interparticle forces, the non-plastic fine-grained soil mixture may not obtain sufficient compaction density. This study aims to propose a solution to deal with these problems mentioned above by interparticle force regulation making use of interfacial forces reduction surfactant. The influence of changes in interfacial forces on compaction density has been investigated attentively in the laboratory and in situ tests, associated with a variety of fine-grained materials content and compactive effort. As a result, the compaction density increased obviously with the reduction in the gas-liquid interfacial forces, and smaller and faster consolidation settlement was observed at compaction sites.

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It has become important to establish a rational, economical method for the grouting work which is a kind of the water stream-stopping work in a rock mass.
We have made a series of research aiming at the cost reduction of cement by using grout (hereafter “soil cement grout”) prepared by adding native soil material (loam or clay containing much fine particles) distributed in the vicinity of a site for the construction of a dam to cement and the quality improvement of grout by using the above-mentioned soil material.

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The surface layers of alluvial plains in Kagoshima are almost covered with the alluvial secondary Shirasu which is eroded by the rainfall, transported from the Shirasu pleatues and deposited on the alluvial plain. In this paper the dynamic properties of alluvial secondary Shirasu ground are referred and discussed by the results of previous research work from a new view point, and a method is proposed to estimate the liquefaction potential of alluvial secondary Shirasu ground. The main results are summarized that (1) the decrease of dynamic shear stress ratio with depth is different from usual sandy soil, (2) by using the inherent decreasing coefficient of shear strength for the alluvial secondary Shirasu and twice N-value obtained by SPT, the liquefaction potential can be reasonably estimated, and (3) the liquefaction potential in the southern part, near coastal line and along rivers, Kagoshima City is relatively higher than one in the northern part.

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It is important for recovering the ground water contaminated by chlorinated organic compounds to search the point of pollutant source. The authors study the methods to detect the point of pollutant source by GA (genetic algorithm) using existing concentration data obtained from monitoring wells. We assume that pollution proceeds by advection and diffusion in two-dimensionally without absorption. Unknown factors detected are a source point, the direction and the velocity of ground water, the concentration of source point, the beginning time of pollution and the continued period of pollution. The method proposed is verified by the virtual numerical simulation and is applied to the actual polluted site.

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This paper discusses applicability of the Hill's condition of stability to granular materials with the aid of numerical simulations performed in terms of the granular element method. It also presents a new version of the granular element method itself before showing results of stress-probe simulations which give detailed behaviors of a specimen model. Results in a stable state show that the non-elastic behavior exhibits incrementally non-linear character which brings deviation from the non-associated flow rule in such a way that the Hill's condition is fulfilled. Other results show that applicability of the Hill's condition is restricted when the heterogeneity is progressing. The latter restriction seems to have its origin among premises appearing in a new derivation of the Hill's condition of stability.

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Grain size distribution curves of decomposed granite sampled from slopes of a reser voir for a pumped storage power plant were analyzed by the negative binomial distri bution in order to estrmate the weathering rate. The verification was made by compa risons with the results obtained from X-ray analysis and chemical dissolution tests. Engineering applications showed that a unique relationship among the parameters was available to relative estimation for weathering of soils at each slope.

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The authors developed a new type joint of shield tunnel segment suitable for highly stable ground. Called “FRP-Key” the new joints consist of FRP tongues partially embedded in the surface of the circumferential joint and the longitudinal joint, and they are fitted with the groove cut on the opposite surfaces. The FRP-Key joint ensures transmission of shear forces and controls the positioning of segments during assembly. This reduces the time required for segment assembly in situ and saves the manufacuturing cost of concrete forms as the joint can be preinstalled in steel formwork. This paper presents the characteristics of FRP and the mechanical characteristics of the FRP-Key joint obtained from various tests, and describes the method of designing segments with FRP-Key joint.

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Bottom granulated ash is discharged by all incineration plants for municipal waste and is buried at disposal sites as general solid waste. It is important to make use of these sites. However, the mechanical properties of bottom ash have not been well understood. The particle properties of typical bottom ash were observed with a scanning type electron microscope in the study. Various tests including the compaction test isotopic consolidation test, drain triaxial compression test and undrained triaxial compression test were conducted on bottom ash. As a result, the particle shape characteristics of bottom ash, the partide breakage property, critical state line, coefficient of earth pressure at rest, stress-strain behavior and dilatancy characteristics of the materials are presented.

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Mechanical properties of rock mass are strongly governed by the microscopic structure that consists of distributed cracks and various rock materials. In order to evaluate the deformability and the strength of such a rock mass, the numerical scheme of multi-scale which is based on both the homogenization method and the limit load analysis is proposed. The data needed are only the mechanical properties of intact rocks and the digital image of crack distribution, which are easily obtained from laboratory tests and survey in site. The deformability and strength of representative element of rock mass are reasonably evaluated from the homogenization analyses. And then the limit load of a rock mass structure is also successfully evaluated by the limit load analysis.

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It is important to prevent surface settlement and stabilize cutting face in a shallow overburden or a soft ground tunnel, which is called urban NATM. The pre-lining method, in which arch-shell linings were formed ahead of the cutting face prior to excavation, has been applied to some construction site. However, the design of this method is not established. This paper describes results of model tests to investigate earth pressure acting on the pre-lining. It is clarified that acting earth pressure changes during deformation and settlement of the pre-lining, and that the axial force of the pre-lining is uniform in a flexible pre-lining.

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Recently the authors proposed a new scheme to evaluate liquefaction potential based on an energy dissipation capacity of ground material. In this study how to evaluate the dissipation energy accumulated in the surface ground during strong earthquake was discussed. The dissipation energy was calculated from the elastic energy and damping ratio evaluated in an equivalent linear analysis. To confirm the validity of the method, we conducted case study of Kobe Port Island array observation site using various strong earthquake motions. It was explained theoretically that the dissipation energy should be used as an index to represent the external force instead of the stress.

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This paper describes the numerical modeling of geosynthetics-reinforcement mechanism in soil structures. The confining effect brought by the geosynthetics working so as to prevent dilation of soils is considered by introducing constitutive models that can express dilation of soils with shear. Then, the deformation-failure behaviors of two full-scale geosynthetics-reinforcement soil structures are simulated using the finite element computation technique. Herein, the compacted soils are treated as saturated-heavily over-consolidated clays and the determination procedure of input parameters needed in the models is proposed. Numerically predicted behaviors are compared with monitored ones.

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Observational Procedure of the excavation work is mainly used for safe management. The prediction based on measurement data during construction is more reliable than the prediction at the design stage before construction. If the values are utilized more effectively, we will be able to execute the construction works rationally. So, Estimation of the design parameters and prediction in the behavior of the structure play the important roles in the observational procedure, and are demanded high reliability.
In this paper, the relationship between the error of measurement data and prediction results and the error in modeling of prediction are specified. And the reliability of the prediction are estimated.

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An anisotropic yield function for rock materials, which is embedded in the stress space with scaled base frames, is proposed for a hydrostatic stress dependent yield criterion. It is shown that a number of classical yield functions are derived from the proposed yield function as special cases.
An evaluation method for the material parameters included in the proposed yield function is shown by using a nonlinear optimization programming method. Their material parameters can be evaluated only by uniaxial compression tests and conventional triaxial compression tests, and do not require any difficult tests as simple shear tests or uniaxial tention tests for their evaluation.
And then, by the comparisons between the theoretical and experimental results on a number of rock materials, the proposed yield function is proved its effectiveness and good expression on various anisotropic characteristics of rocks.

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A series of centrifuge tests was conducted on the stabilizing effect of woven sheet reinforcement under an embankment resting on normally consolidated clay for various ratios of the depth of the clay to the embankment width. The experimental results were presented mainly in view of time dependent behavior of the reinforcement, and compared with FEM analysis. Bearing capacity analysis using stress characteristic method was also conducted to examine the reinforcing effect to be viewed by the increase in inward shear stresses developed along the sheet.

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This paper presents the new methodology associated with the stability analysis of slopes. As for current design methods, the basic concept to determine the required factor of safety is vague. Essentially, the required safety margin to slopes should vary in accordance with the utility of each slope from socio-economical viewpoints. Therefore, this study applies the concept of performance based design to take into account the utility of slopes. The conclusions make it obvious that the methodology proposed in this study is very useful in the design of slopes.

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This paper deals with the estimation of bearing capacity of cast-in-place pile based on the CPT-data. In order to propose the method, 11 in-situ loading test results on cast-in-place piles and the CPT-data obtained at the same sites of loding tests were used. The comparison between the results of loading test and the estimations based on CPT-data using proposed equation, shows fairly good agreement. Moreover, it was confirmed that the bearing capacity presumed by this method has a high safety index in the design revel II of the reliability based design.

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To study the lateral bearing capacity of piles and sheet piles in clay slope, laboratory tests were carried out to investigate the influence of slopes on the lateral resistance of sheet piles as well as failure mechanism of the slopes. On the basis of the experimental results, the passive resistance of slope was calculated by using the upper bound theorem. In addition, the deformation of the sheet pile was calculated considering the elastic and plastic sabgrade reaction of the deforming ground. From the comparison of calculations and experimental results, it can be concluded that the present analysis method is useful in predicting the lateral bearing capacity of the sheet piles in the sloped clay ground.

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The statnamic load test is a more convenient method than the static load test for estimation of the bearing capacity of a pile. This paper proposes a nonlinear dynamic analysis method of pile in statnamic load test. The behaviors of pile in statnamic load test can be modeled as a vibration of single-degree of freedom model. The soil spring is assumed as a bilinear spring and the equivalent damping coefficient is calculated from the load-settlement hysteresis loop. The analyzed results are very close to the measured displacement, velocity and acceleration at the top of the pile. Yield bearing capacity of the pile is obtained in the nonlinear analysis.

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In the practical problem of the geotechnical engineering, such as the bearing behavior of footings, formulae based on the critical state analysis have been generally used, because of the easiness and reliability. However, for the sake of more rational estimates, it has become extensively recognized that bifurcation need to be taken into account. This paper investigates not only three-dimensional effects but the bifurcation phenomena in the bearing behavior of rectangular footings. The asymptotic bifurcation theory is applied to a load versus displacement curve from an experiment, and the bifurcation behavior associated with the variations of strength and failure modes is revealed.

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The stability of underground cavern is strongly controlled by joint distribution in the case of hard rock mass. Stochastic Block Theory has been suggested for the effective observational construction of large underground caverns. The probability of forming a removable block by the subsequent excavation can be obtained from actual field data for stochastic estimation of discontinuitiy distribution in the hidden region. In this study, the appropriateness and applicability of Stochastic Block Theory are verified based on the simulation results on one of the largest underground excavations in Japan.

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Long term measurements of ground movements were made at three different sections around an earth pressure balance shield tunnel construction in Yurakucho lower clay. The data were examined in view of tail void settlement and subsequent settlement. The results revealed that (1) it is rational to distinguish the tail void settlement and subsequent settlement by the change in vertical strain immediately above tunnel crown, (2) ground deformation during tail void settlement could be approximately expressed by an elastic solution for a cavity in an infinite media, and (3) soils around the tunnel move predominantly downwards during subsequent settlement.

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A seismic cone, equipped with two receivers, was developed to measure in situ shear wave velocity. Using this cone, site investigations were conducted at several sites with different subsoil conditions. Due to its two receivers, the cone was able to measure the shear wave velocity of ground more precisely than the conventional P-S logging of down hole type. The case studies indicated that the strain level caused by the seismic cone is of the order of 10^-6 to 10^-7. The damping factor h estimated from the seismic cone using spherical wave formula showed values in good agreement with that measured in laboratory using undisturbed samples.

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Mechanical behavior of clay ground improved by SCP with low replacement area ratio could be more significantly affected by mechanical interaction between sand piles and clays than that of clay ground improved by SD or by SCP with high replacement area ratio. It is essential to elucidate the mechanical interaction in the improved clay ground, in order to accurately estimate behavior on reducing settlement of the improved ground and increasing strength of clays. In this paper, through a series of model tests and numerical simulations of clay ground improved by SCP with low replacement area ratio, each mechanical behavior of sand piles and clays in the improved ground during consolidation is elucidated, together with stress sharing mechanism between sand piles and clays.

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In order to obtain p-y curves of single pile in sandy ground, a divided pile loading system has been developed. The p-y curves can be directly measured from small to large displacement with this system. A series of centrifuge model tests has been conducted to investigate the effect of depth and diameter of piles on the p-y curves. It was found that the p-y curves can be modeled by hyperbolic curves with initial gradient of subgrade reaction k_h and ultimate subgrade reaction p_max. An attempt was also made to simulate the behavior of horizontally loaded single pile by p-y curves obtained from the divided pile loading test.

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In foundation design, the deformation characteristics of the subsoil has been conventionally modeled by a coefficient of subgrade reaction. However, it has not been confirmed if the scale effect on coefficient of subgrade reaction can be applied to large foundations. To investigate these effects, in-situ horizontal loading tests on gravelly subsoil using loading plates of different size were conducted at a bridge construction site. The results were simulated numerically by three dimensional finite element method considering nonlinear and pressure level dependent deformation properties of subsoil, which were modeled based on the triaxial test results that were performed on undisturbed specimens. The numerical results agreed well with those of the in-situ tests in the region of small strain level and showed that the extent of scale effect on coefficient of subgrade reaction depends on the condition whether it is compared at the same load intensity, the same strain level in the subsoil or the same displacement of foundation.

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Unique 3 dimensional shape so-called “SORI” is observed on the masonry walls (m. w.), which not only gives a solid and stable impression but is also technologically logical. However, as to the origin of this shape, many points are yet to be explained.
Having studied the application of F. E. M. for section analysis of m. w., the figures similar to “SORI” is obtained. Thus our results show that the origin of the 3-D shape of m. w. must be attributed to the natural settlement or displacement of the m. w. when piling them up.

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Large part of deformation and failure of rock masses are governed by both characteristics of geometrical distribution of discontinuities and those of mechanical behavior in a single discontinuity in slopes, foundation ground and caverns. It is thought that stability of those rock structures extremely depend on not only existent discontinuities but also new cracks which are generated and progress due to loading or excavation. In this paper, a new approach is proposed for modeling generation and progress of cracks due to shear and tension failure in the matrix by using distinct element method. Next, appropriateness of the approach are verified by means of comparison with result of theoretical analysis for the problem of cylindrical hole and bearing capacity of strip footing on slope. As applications to field problems for discontinuous rock masses, simulation of underground opening excavation and footing of bridge on slope are also carried out.

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Recently, in Japan, many dam sites are composed of soft rocks or gravel deposits. For these foundations with very low strength, seepage failure potential should be investigated accurately and efficiently in the designing stage.
In-situ seepage failure test was conducted for gravel deposits, which had been evaluated to be low in seepage failure potential from the results of previous investigation using laboratory seepage failure test and simple tests such as needle penetration test and pick penetration test. For the easier analysis of results, in-situ test was made on horizontal one-dimensional flow condition. In this paper, the method and the results of in-situ test were reported, and guidelines on investigation of seepage failure potential of dam foundations were also proposed.

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A theoretical analysis is presented that compares the response characteristics of the constant head and constant flowrate laboratory techniques when testing geomaterials having K<10^-10m/s. Rigorous solutions are developed for each method that describe the transient distributions of hydraulic head and hydraulic gradient within a test specimen. Expressions simulating the inflow and outflow rates across the specimen boundaries during a constant-head permeability test are also presented. These solutions illustrate the advantages and disadvantages of each method, including insights into measurement accuracy and the validity of using Darcy's law under certain conditions. The efficiency of the flow pump technique with the rigorous solution are supported by its application to a bentonite-sand mixture.

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In this paper, after reviewing the approach to generalize the elastoplastic model for soils with the initially stress-induced anisotropy by the SMP criterion, the inviscid Sekiguchi-Ohta model is revised by using a transformed stress tensor σ_ij, which is deduced from what makes the SMP criterion become a cone with an axis at the space diagonal line in the transformed principal stress space. The revised model is then extended to be a unified elastoplastic model for clay and sand by introducing a new hardening parameter H, which can describe the negative and positive dilatancy characteristics of soils. Model complexity is controlled through only adding one material parameter to those of the Sekiguchi-Ohta model. Extensive comparisons with experimental data from drained shear tests in different stress paths show that the proposed model gives excellent predictions, and especially for K₀ normally consolidated clay, the model is more realistic than the Sekiguchi-Ohta model in predicting the deformation and strength of soils. Finally, the elastoplastic constitutive tensor is derived for the application of model to finite element computation.

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The applicability of the in situ freezing sampling method for sands containing fines is discussed in this paper. Procedures for evaluating in situ frozen sample quality of sands containing fines are proposed based on the fact that the reduction in liquefaction resistance can be uniquely related to the volumetric expansion during freezing for sands containing up to 20% fines. Based on the heat conduction analysis of the ground and frost expansion tests of the soil, an analytical solution, which forms the key of the proposed procedure, is then obtained by coupling the frost expansion strain and confining stress. This paper also presents a case history in which this sample quality evaluating procedure was applied in actual freezing sampling on ground containing fines.

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The authors have proposed a new dynamic compaction technique making use of not only free fall energy but also rotational energy of the hammer for the purpose of the advancement of the densification of the granular soil ground. In this study, the small scale model tests and the large scale field tests to simulate the usual dynamic compaction method (DCM) and the dynamic compaction method with rotational hammer (RDCM) were conducted. From the test results, it is verified that the increments of the cone penetration resistance by RDCM are generally larger and the settlement of the ground surface by RDCM is larger than DCM.

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This report presents a concept for the design of lining of a non-circular shield tunnel, which is an approach adopted to deal with restrictions in the tunnel width imposed by a land boundary and by foundation piles. This report also presents the results of field observations, and a method of analysis to forecast its effects on surrounding ground. From the field observations, interesting results concerning the load and deformation of the surrounding ground were obtained along with desingn related knowledge of use in future shield tunnels including that for circular tunnels.

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In the period between March and August in 1997, earthquakes occurred in swarms with their epicenters near Sendai City, Kagoshima Prefecture. Motions of seismic intensity between slightly larger than 5 and a little smaller than 6 were frequently recorded in the Kushikino storage plant. During the earthquakes, invaluable data on hydraulic behavior in rock were obtained continuously.
In this study, behavior of the dynamic pore pressures measured during the earthquakes is studied by checking the rock conditions at measurement points, seismic behavior of the groundwater system in the storage area is considered, and knowledge about hydraulic behavior in rock obtained during the earthquakes is presented.

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Tunnel loading experiment was executed to investigate the effect of lining rigidity. A loading device was made to observe the interaction between tunnel lining and the surrounding ground. The surrounding ground is modelled by steel rod layer. The vertical load is supported by both lining and surrounding ground. Large bending moment is arised in case of rigid lining under the stiff ground condition. In such a case the flexible lining is preferable to utilize the surrounding ground strength.

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When plural kinds of piles coexist in a foundation, the pile settlement characteristic influences the foundation behavior greatly. For example, when new piles are added for the reinforcement of an existing bridge foundation supported by piles, the new pile's behavior differs from the existing pile's behavior in the stress and the settlement. It is difficult to carry out such a pile foundation design reasonably without considering the pile settlement characteristic. The settlement estimate equations were proposed that are applicable to the practical design in such cases. The proposed equations make the pile foundation design reasonable. This paper also showed the pile foundatin design method using the equations.

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The factors of discontinuity plane which affect the shear behavior of rock joint are the strength of intact rock, roughness, aperture etc. In these factors, there is many researches in related with the roughness. However, although the aperture condition of rock joint is important factor, the many researches with this factor have not been performed. In this paper, the effects of which the shear behavior of rock joint is depended on the magnitude of aperture condition are discussed. Especially, the numerical index representing the degree of the aperture condition with rock joints is proposed, and furthermore, we applied this index on the shear strength equation proposed by authors.

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