Several finite element procedures for frictionless- or friction-contact problems have been proposed for the case in which node-to-node contact no longer holds. One of the typical computational algorithms is the nodal mis-match algorithm in which contact interface is discretized into contact segments. In this paper, the nodal mis-match algorithm to allow arbitrary finite element mesh is generalized by using a perturbed Lagrangian formulation and localized mixed concepts.
A numerical analysis for the excavation problem of shield tunnel was carried out by using the proposed algorithm. The numerical results were well similar to the ground behaviors observed in situ.

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The mechanical effect of the interaction between the shotcreting and the ground is studied from a view point of the tunnel support stability. A serial set of rigid bars jointed through the bending springs are adopted for a model of the lining while the constant coefficient of subgrade reaction is assumed for the ground. A lot of parametric numerical analyses are done by changing the width of shotcreting, the coefficient of the lateral earth pressure, the overburden and the shape of tunnel section. It is shown that the subgrade reaction is essential for the tunnel stability and that even a thin shotcrete lining supports the surrounding ground if an adequate amount of the subgrade reaction is expected.

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This paper presents a case history on the penetration of cylindrical caisson-type foundations into the seabed by use of the suction force. The purpose of the study is to propose a method for estimating the suction force necessary to penetrate the so-called suction foundation into the seabed. The results of theoretical analysis were compared with the field data collected from 2 sites where the suction foundations were actually installed. The sensitivity analyses of several affecting parameters on the decision of suction force were also made. It is concluded from the study that the proposed procedure can be successfully applied to estimate the suction force, when the input data for the analysis are appropriately determined.

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The air intrusion method based on the capillary model was produced to measure the distribution of soil void diameter. In the present paper, the void diameter distribution measured by air intrusion method is compared with the one estimated from moisture characteristic curve. As a result, it is shown that the shape and range of void diameter distributions by air intrusion method become more uniform and more narrow than the distributions by moisture characteristic curve, respectively, and that the mean void diameters by air intrusion method correspond to 90% of that by moisture characteristic, with consideration of the connecting relationship between both curves, and so on.

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If the characteristic is standardized every pile types, it is very convenient for the design work of pile foundation. Recently, there is a tendancy that buildings are built by reusing existing foundations. The foundations of these buildings are likely made of different types of pile, therefore, it is important to know fully the settlement characteristics of the each pile in the design process. Based on such intention, curve fittings for the relationship between load and settlement of piles were carried out by using data of many pile loading tests. The most suitable curve equation was searched that represents the settlement characteristic of piles. The relation between parameters of the curve equation and the pile species was analyzed by the multiple regression analysis. At the results, an equation was obtained that represents the settlement characteristic every pile species.

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It is thought that a best way to apply a distinct element method built in reliable mechanical models of discontinuities to the estimation of mechanical stabililty of underground openings and to bring its results into designs. In this paper, the conditions that formulation has appropriateness and reliability, are shown by means of taking up some representative models in the past and by considering any questions in the formulations. Next, a new mechanical model of discontinuities which is based on that considerations is proposed, appropriateness and reliability of the model are verified by means of comparison among the result of shear test, and the comparison between the proposed model and Barton model in the reproduction analysis of shear test. As an example, simulation of underground opening excavation is tried.

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Theoretical solutions of p-y curve for a pile or a buried pipe loaded by lateral soil movements are presented. These formulations are based on the elasto-plastic theory under some assumptions of deformation pattern of soil around the pile. The models can express the behavior from initial elastic state to ultimate state and take the appearance of the void behind the pile into the account. In order to validate the models, the pull-out tests of model piles lying in clay were carried out. It is conformed that one of the models compares very well with the results of the tests until the drop of the contact pressure due to the void occurs.

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By-products of the construction industry, such as mud and dredged earth, and of electricity generation, such as fly ash and desulfurized gypsum, have for many years not been recycled, owing to their poor quality, and this brings about a serious environmental concern. This research focusing on the use of fly ash and gypsum to revitalize poor quality soils has revealed several factors affecting the quality improvement processes. The key factors, found by analysis of variance and multiple regression are the proportion of water initially present, the proportions of added quicklime and fly ash, the interaction between them, and the proportion of added gypsum. The research has also found the appropriate quantities of the materials to be added.

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A hard-rock tunneller MM130R was used at Takatoriyama Northward Tunnel and the distribution of the specific energy of MM130R was measured. The procedure to accurately evaluate the specific energy of MM130R was discussed. The specific energy was found to be well-correlated with the rock properties such as Schmidt hammer rebound and seismic velocity measured at a few tunnel faces. The contour plots of the distribution of specific energy on the horizontal plane along the tunnel drive successfully visualized the geological structures with weathered joints, which were parallel to the major faults observed near the tunnel location. The excavation efficiency of MM130R was estimated to be comparative with a conventional hard-rock tunnel boring machine.

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A calculation method of probability of liquefaction is proposed in this paper. The spatial variability of soil parameters for the dynamic shear strength, N-values, median grain size, fines contents, and the statistical characteristics of the earthquake occurrence are considered in the analysis. Using this method, the reliability design of the sand compaction piles is discussed for the ground improvement against the liquefaction. The optimum sand replacement rate is determined so as to minimize the total cost.

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In this paper, firstly Budiansly's model which is well-known as the yield vertex model in metal materials is discussed in detail and it is clarified how non-coaxial components effect on the shear band initiation and the bifuration point of stress-strain relationships. Secondly the elastoplastic model of dilatant materials in plane deformation is introduced by adding non-coaxial components to Mohr-Coulomb's flow model. In addition the special element whose nominal stiffnesses are soften is proposed in order to analyze the shear band of dilatant materials. FEM analyses concemed with biaxial tests are performed As the result the above model and the special element are able to express the relations among patterns of shear band, material constants and the localization of deformation

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In chemical grouting, it is difficult to evaluate the improved region. To solve this problem, authors proposed the evaluation method of improved region by resistivity tomography. For a practical application of this method, this study shows the validity of proposed evaluation by chemical grouting test in field The sodium-silicate grout was used in this test. The field test result showed that improved regions, which were evaluated by the proposed method using resistivity tomography, almost agreed with the solidified regions of boring samples. The test results described above ascertain the availability of the evaluation method of improved region by resistivity tomography in practical fields.

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In the quality control for cast-in-situ piles, it is hard to estimate the condition of piles after the concrete placing. Therefore, the tape measure is used generally for depth measurement of the excavated hole just after drilling. However, it is feared that the pile shape is different from the design one by the influence of ground water. Far the purpose of researching the applicability of the integrity test that is a nondestructive method, we carried out field tests in 26 sites of nationwide. The following results are obtained from the tests: (1) Integrity tests are useful for the estimation of the pile length, however, errors (about 3%) are included in test results, (2) If the stiff middle layer exists, estimation errors will increase, (3) Statnamic testis fully practical for relatively short piles.

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The top of geomembranes should be anchored firmly not to slip out. It is known that the thermal stress which occurs with the decrease in temperature should be a large portion of the forte which affects the anchoring section. Reliable equations for evaluating thermal stress cannot be found in literature. The authors conducted the chamber test under the oondition of confining with both ends of a sample and the large scale field test and evaluated the relationship between the temperature and thermal stress. As the result, it is found that (1) the thermal stress is much different with the type of a geomembrane, (2) the thermal stress of the test result under the condition of confining with both edges of a sample can be evaluated with the equation of the theory of elasticity, (3) when a vonfining force occurs by the weight of a soil layer, the thermal stress is smaller than the thermal stress under the condition of a strict confining. And the evaluating equation was presented.

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Chemically induced change of the strength of sandstone and granite has been investigated to establish the fundamental knowledge for chemically enhanced fracturing, together with acoustic emission measurement during the experiments. The tensile strength varied with the concentration of chemical additives, became the lowest at the particular concentration which are consistent with the zero zeta-potential concentrations. AE activity is the most active in dry specimen, and the least AE activity was found in the saturated specimen with the chemical solution. The triaxial strengths did not vary significantly with concentration of the chemical solutions.

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Direct shear test results with Mikasa's apparatus are presented for Ariake (Japan), Bothkennar (U. K.), Champlain (Canada) and Drammen (Norway) clays which are representative soft marine clays in the world. Direct shear strength of the four clays measured both in the normally consolidated state and in the field state are indicated and discussed together with stiffness. In addition, distribution patterns of the in-situ shear strength and various shear strength from unconfined commpression, field vane and cone penetration tests are shown.

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For estimating the behavior of Tokoname layer consisting of alternating strata of siltstone and sand during the excavation of an in-ground LNG tank, deformation properties are investigated by laboratory tests of undisturbed samples obtained by block sampling method and in-situ tests. In a triaxial compression test, Local Deformation Transducer (LDT) is used to measure the axial strain without the effects of bedding error at the specimen ends. Shear wave measurement is undertaken to study the effects of disturbance by sampling. The study shows that strain amplitude and confining pressure are considered as important factors for evaluating deformation properties of Tokoname layer, whereas anisotropy and disturbance by sampling are not as significant.

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