This paper presents a regressive model to deduce the internal forces and soil reactions of a laterally loaded test pile from the data of inclinometer measurements. This model simulates the distribution of bending moments of the pile by using a composite function of which the upper part is modeled by a polynomial and the lower part is modeled by the characteristic function of an analytical solution for a semi-infinite pile supported by uniform Winkler soil springs. Through successive regressive analyses, the optimal composite function obtained can effectively simulate the pile responses including the deflections, bending moments, shear forces, and the associated soil reactions. For verification, both the solution of a finite element analysis and the results of an in-situ load test have been adopted and the results of regressive analyses can satisfactorily obtain the pile responses. In addition, on the basis of curves of pile deflection and soil reaction deduced from the results of the pile test, a set of site-specific p-y curves can thus be established. Finally, a parametric study has shown that accurate estimate of moment-curvature relationship of a pile section is essential to the accuracy of the deduced pile internal forces, soil reactions, and p-y curves.

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A simplified slip line solution of the axi-symmetric active earth pressure based on a general lateral stress coefficient for general c-ψ soil system is developed in the present paper. The results from the simplified slip line analysis are compared with those by Prater and results from numerical modeling. It is found that Prater's method may give surprising results and the limitations of Prater's results are also discussed in this paper. The authors have also investigated the importance of the lateral stress coefficient and the lower bound of the coefficient which are not considered in the past.

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This paper presents a hysteresis model of soil water retention curves based on bounding surface concept. In the bounding surface concept, the plastic modulus is defined as a function of the distance between a current stress point and the conjugated stress point on the bounding surface. We adopt the similar idea that the slopes c (=−∂S_r/∂s) of soil water retention curves are defined as a function of the normalized distance between a current point and the conjugated points on main curves (main drying and wetting curves). The modeling of main curves was conducted by Tangential model proposed by the author. Tangential model insures the continuity of slopes of soil water retention curves. The model may well trace the soil water retention curves as if pore water pressures are both positive and negative. The model needs not to identify the parameters. Only three points are selected and the values of degree of saturation S_r, suction s and slope c at the points are input. Soil water retention curves for three samples with cycles of drying and wetting were simulated using the model. The simulation results showed good agreements with the experimental ones.

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At present, analytical or empirical formula for seismic bearing capacity of footings adjacent to slopes is not available. This study uses a pseudo-static-based approach in conjunction with rigorous Janbu's slice method to derive analytical values of seismic bearing capacity factors (N_γ) and correction factors for the effects of inertia of soil mass and load inclinations for a rigid footing adjacent to cohesionless slopes. It is shown that both the bearing capacity factors (N_γ) and the correction factors for the seismic bearing capacity of footings placed on level ground derived herein are comparable with those reported in the literature. Empirical equations regarding the effects of slope angles and load inclinations, expressed using generalized forms of those proposed in the literature, are also derived. It is also found that the empirical equations derived in the present study provide values of correction factors in good agreements with the analytical ones, indicating the validity of using these empirical equations for assessing the bearing capacity of rigid footings situated on the slope subjected to pseudo-static seismic loading.

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The crushed Tertiary Period mudstone used as the geomaterial for the artificial reclaimed land in the Joetsu Region of Japan consists of coarse and fine fractions of about 50% each and is classified as an “intermediate soil.” Unlike sand or clay soils, no constitutive equations or sufficiently established design methods have been available until now for evaluating intermediate soils. This paper first utilizes the SYS Cam-clay model (Asaoka et al., 2002) to identify the soil profile of intermediate reclaimed land through comparison of laboratory test results with the calculated responses of the constitutive equation. Next, the soil profile obtained is used to carry out various soil-water coupled finite deformation analyses. The main conclusions reached are as follows:
1) The rates of decay/collapse of the soil structure, loss of overconsolidation, and evolution of anisotropy of the soil materials that constitute the Joetsu reclaimed land lie midway between those of typical sand and clay.
2) Ground improvement by cavity expansion of sand piles is effective in converting the reclaimed land from a highly structured ground having heavier overconsolidation to a lightly overconsolidated ground with a low degree of structure by increasing the confining pressures within the ground. In particular, the reduction in the specific volume of the soil elements in the vicinity of the sand piles becomes large.
3) In the case of small vertical displacement, the composite ground containing the sand piles exhibits a bearing capacity of about 1.5 times that of an unimproved ground, and in the case of large displacement, the bearing capacity is about 2 times larger.

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We conducted a series of 1G large-scale shake table tests and cyclic eccentric loading tests of a shallow foundation model. The experimental parameters were the difference in loading methods (i.e., dynamic and static), input seismic motions (i.e., intensity and number of cycles), soil densities (i.e., dense and medium dense), and the ratio of horizontal and overturning moment loads. The experimental data set contains the accelerations and displacements of the soil and foundation as well as the distributions of normal and shear reaction forces at the foundation base. The experimental results provide crucial data to model the coupling effect among vertical, horizontal, and overturning loads, the accumulation of irreversible displacement, and the foundation uplift, and so is one of the most complete benchmark data sets for the development and validation of numerical models for the nonlinear response of shallow foundations to strong earthquakes.

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A dynamic analysis model for the nonlinear behavior of a shallow foundation subjected to seismic loads is developed. A macro-element approach is revised assuming elasto-uplift-plastic behavior, in which uplifting and coupling effects of vertical, horizontal, and moment loads are taken into account. Large-scale shake table experiments of model pier footings are also conducted and simulated using the revised macro-element model. The numerical result reveals that the shape of the hysteresis loops for coupled load-displacement relationships is predicted very well, including the effects of uplift. In addition, the revised model can account for settlement with some inclination that has accumulated during the excitation.

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Monotonic and cyclic triaxial tests were carried out on sand-silt mixtures for the investigation of the effect of fines content on their critical state and liquefaction resistance characteristics. Both the undrained and the drained monotonic tests produce a unique critical state line for each tested mixture, which moves downwards with increasing fines content up to a threshold value of 35% and then upwards. At a given void ratio and mean effective stress, the liquefaction resistance ratio decreases with increasing fines content up to the same threshold value of 35%, and increases thereafter with further increasing fines content. However, at a given intergranular void ratio, defined as the ratio of the volume of fines plus voids to that of sand particles, liquefaction resistance ratio increases with increasing fines content up to the threshold value. The threshold fines content value, which is an important parameter in determining the transition from the sand dominated to the silt dominated behaviour of sand-silt mixtures, is related to their particle packing. An expression is proposed for the estimation of the threshold fines content as a function of the mean diameter ratio, d₅₀/D₅₀, and the void ratio. The results, presented herein, also show that for each tested mixture the liquefaction resistance ratio is related to the state parameter and that this relation is influenced by the effective stress level and fines content. The results on the sand-silt mixtures are supported by similar results on natural silty sands.

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In order to study the cyclic behavior of liquefied sands at extremely large strain levels up to double amplitude shear strain of about 100%, a series of undrained cyclic torsional shear tests while keeping the specimen height constant was performed on saturated Toyoura sand under different densities, two kinds of in-situ frozen sandy samples and their reconstituted specimens. Due correction was made for the effect of membrane force on the measured shear stress. After exceeding a certain level of overall shear strain, the specimen deformation became non-uniform, which is called as “strain localization” in the present study. The initiation of such localization was associated with the changes in the cyclic amplitude of deviator stress and the increment of shear strain. In the case of Toyoura sand, the limiting value of shear strain to initiate strain localization was found to increase with decrease in the relative density, and such a trend was consistent with the empirical correlation of soil liquefaction when the relative density is higher than 30%. In the case of in-situ frozen sandy samples, their limiting shear strain values were smaller than those of the reconstituted specimens, suggesting that their soil structures were different from each other under different degrees of natural aging effects.

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