Lateral loads on piles arise from a variety of causes. In the case of an embankment adjacent to a piled foundation, the lateral loads acting on the piles are induced by the horizontal movement of the soil as a result of the embankment load. Allowances have to be made to ensure that the piles have the capacity to resist the applied bending moments. In this paper, a simple method of estimating the applied bending moments in piles is proposed, based on the finite element method and the Winkler foundation method. Various charts are provided for estimating the lateral displacements of the piles. In addition, analyses have been carried out to study the behaviour of piles under the effects of different loading conditions and boundary conditions.

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Pockmarks are craters formed in the soft seabed by gas and in some cases liquid expulsion. They were first described on the Scotian Shelf in 1970 (King and MacLean, 1970) and have since been mapped in a range of shallow seas including the North Sea and the Arabian Gulf. Pockmarks range in size from less than one metre to about 200m across and up to 20m deep.
There are assumed to be three phases of pockmark development:
1) The pressure build-up phase, whereby gas accumulates and builds up local pressure below the seabed.
2) The eruption phase, where by gas, liquids and solids are ejected into the water colum, and
3) The post eruption phase, which can either be a dormant phase or one where gas is continually seeping through the pockmark floor.
Triggering of pockmark eruptions are discussed. They may be triggered by earthquakes or seabed pressure perturbations caused by tidal or gravity waves or, in deep water, by a combination of tidal waves and low atmospheric pressure and storm waves.
Pockmarks are of concern in relation to seabed construction.
Pockmark avoidance and crossing with pipelines is discussed together with methods of artificial gas drainage away from construction sites.

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In this research, a new designing method of gravel pile systems against liquefaction of level ground during earthquakes is proposed. The proposed method has some advantages over the existing methods. Small scale vibration tests were performed in order to verify the applicability of the proposed method. As for the behavior of excess pore pressures in the improved ground and surface settlements of the improved ground, experimental results indicated satisfactory coincidence with calculated results.

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A series of studies have been conducted in order to develop a new designing method of gravel piles against liquefaction of level ground during earthquakes. In this report, we verified usefulness of the designing method which had been already proposed using upon in-situ liquefaction test results. As for excess pore pressure and surface settlement of the improved ground, experimental results coincide well with calculated results.

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A soil structure such as embankment or a surface ground shakes and is deformed due to an earthquake force. As a result, the stiffness of soil decreases by the effect of a strain during the vibration. It is possible to express the effect of the strain by the store of the strain energy that is absorbed into a soil.
The saturated sand liquefies due to the effect of the strain during the strong earthquake motion. Therefore, by using the results of the on-line experiment, we calculated the amounts of the strain energy till the saturated sand liquefied perfectly.
As the results of the analysis, the amounts of the strain energy and its store process required to liquefy perfectly are revealed.

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This paper explains the method and presents an example of the application of a stability control system for about 40m deep excavation in mud rock.
At the case of use this system, the first, fix the critical strain of rock by stress-strain curve of rock core test, the second, calculate the shear-strain of the ground from deformation behavior, and then evaluate the stability of excavation by comparing with them.
The following results are obtained from field observation by applying the system. The strain due to the entire diformation of excavation is comparatively small. The local strain due to a slip of the rock mass is vary large and the corresponding safety factor is very low. However, it is not unstable unless the separated rock block from ground is formed.

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In order to elucidate the mechanism of hydraulic fracturing in sandy ground, we investigate the relation among the hydrofracturing pressure, the confining pressure and the permeability of sand through the injection tests on several kinds of sands, including the cemented sands as well as the cohesionless sands. The result is the following equation.
P′_f=mσ′₃+σ_t+R
P′_f: hydrofracturing pressure, m: constant (1<=m<=2)
σ′₃: confining pressure, σ_t: tensile strength
R: resistance of crack progression
The value of R depends upon the permeability of sands and increases as the permeability increases.

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This paper deals with the optimization of a heat insulator in a double lining for icicle prevention, in which a heat insulating material is sandwiched between the outer and inner linings. A tunnel model using a non-steady state heat convection/conduction is proposed for a tunnel-ground with adiabatic treatment. The calculated values well agreed with the observed values of actual tunnels. Then using the tunnel model a procedure to select the material and the thickness of a heat insulator is proposed. Thus a heat insulator to be provided in a newly constructed tunnel with an adiabatic double lining can be designed reasonably and economically on the basis of the periodicity of an atmospheric condition and the thermal conditions of a tunnel-ground.

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In many tunnels, icicles and side-wall ices usually grow in cold climate. Ranges of icicle/side-wall ice formation from tunnel entrance are estimated by a multiple regression analysis and by a theoretical analysis considering heat convection/conduction between the tunnel-ground and the air flow. The calculated values well agree with the observed ones. The necessary length of anti-icicle treatment from tunnel entrance can be quantitatively determined according to several external conditions such as atmospheric phenomena, thermal conditions of the tunnel-ground and so on. Also the distribution of fluctuation amplitude of atmospheric temperature in a tunnel can be predicted by the theoretical results.

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This paper investigates the behavior of shield tunnels reinforced by secondary lining based on experimental results. Test models are composed of notched steel rings with mortar cast-in-place to their interiors.
Concentrated load is applied at the models which are elastically supported. Three major types of the models are experimented; the two of which are one with dowels and the other without dowels between steel and mortar rings, and that the third is a model in which bonding between outer and inner rings are increased by using resin mortar as a secondary lining. Based on the experimental results, analytic model for two-layer structures, the model for composite structures and the model for intermediate state of structures are proposed. Furthermore the study is made on the application of those analytic models to design practice of shield tunnels.

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An elastoplastic analysis is presented using a newly developed element which includes a plastic shear band. It is called the cracked triangular element. This element can express a stress-induced anisotropy of geomaterials with development of internal cracks. The orientation of a crack in a triangular element is determined by Mohr-Coulomb's failure criterion. And the stress-strain behaviour of shear band is decided by the flow theory of plasticity. Finite element analyses are performed for a triaxial compression test and a punching shear problem. The results of these analyses are shown to well correspond with experiments and theoretical values. Especially, strain-softening phenomenon are observed in compression tests under the condition of stress transfer method with cracked triangular element.

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Fracture toughness tests of rocks were performed to investigate a crack propagation behavior and fracture toughness (K_1C) of rocks under a confining pressure or a low temperature. Fracture process markedly indicated nonlinearity. So, in this paper a crack length is evaluated by compliance calibration technique using results of fracture toughness test and then K_1C is calculated with a maximum load and a crack length. As for a shape and scale effect of K_1C, experiments showed that beam specimens was adequate for rocks. K_1C of rocks linearly increases in the pressure range to 15 MPa and a temperature dependence of K_1C is caused for water saturated rocks. A cyclic strain incremental tests indicates that J-integral is a effective parameter as the crack growth criteria.

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Changes in drained shear strength S_d due to swelling under isotropic stress condition were investigated for organic soil. The relationship between rate of undrained strength increase S_u/σ₀ and overconsolidation ratio OCR is represented by one straight line in logarithmic plot. But in drained condition (lateral pressure σ₃ is constant), the relationship between S_d/σ₀ and OCR can not be expressed by straight line. In this paper, based on the test results, the authors supposed two failure lines (“wet” and “dry” side) and an unique relationship of slopes of state paths with OCR in e-In σ plane, and proposed a method for estimating relationship between S_d and OCR.

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Coupled elasto-plastic deformation-flow finite element analysis has been frequently used for the prediction of displacements, stresses and pore water pressures in geotechnical problems. However, the analysis is not suitable for the stability problems since its numerical results often become unstable after the stress paths of elements arrive at the critical state.
The analytical method including “imaginary viscosity method” which is a usual viscoplasticity computation scheme is developed to analyse the behavior of soil from the initial stress stage to the failure one.
In order to assess the validity and the applicability of this method, a problem of bearing capacity and an actual embankment are examined.

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In order to clarify the injected shapes by the long gel time grouts in the sandy ground, we investigated the relation among the inject rate, the inject pressure and the permeability of sands. The injection tests on several kinds of sands of which permeability was 10^-2--5(cm/s) were performed through the triaxial injection apparatus (the diameter of specimen D=470mm). The main conclusions are summarized as follows: 1) the allowable inject rate depends upon the confining pressure as well as the permeability of sands. 2) the critical inject rate that enables the permeation grouting can be determined by the relation between the inject rate and the inject pressure in the steady flow condition.

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The concept that the compressive strength of rocks usually falls within the range of two or three times the strength of its minimum value seems to be accepted in engineering fields in Japan. The authors suggest that such a wide distribution of the strength was from the experimental conditions. Carefully arranged experiments (experiments: No. 1) and normal experiments (No. 2) were carried out. Although the same granite specimens were used, the scattering of the data in No. 1 was very small but the data in No. 2 was scattered widely. The applied bending moment was calculated from the strain deviation of four axial strains at the periphery of each cylindrical specimen. The observed strength decreased with increasing bending moment. The strike of the fault was nearly parallel to the rift plane for the carefully arranged experiments. However, in experiments No. 2, the strike varied widely, showing that the intrinsic nature of the rock can not be easily discovered because of the disturbances of the experimental techniques.

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To construct safely and economically a shallow tunnel with shotcrete and rockbolts, we have to understand the basic ground behaviour around the tunnel. This paper deals with the field measurement results as to settlement behaviour of ground above nine shallow tunnels in diluvial sand.
From the view point of tunnel advance, eleven typical phenomena were recognized on and in the ground associated with the construction procedures in case that shotcrete and rockbolts were adopted as main support members. They apparently show the importance of focusing on the phenomena along tunnel alignment and their interdependence in all direction in the ground. Hence they also proved to be effective information to assess qualitatively the ground condition, support design and construction procedure.

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To predict the following ground movement and detect the failure of the ground, it is important to assess ground conditions at that time based upon field measurement results as possible as we can.
From the experiences of nine shallow tunnels' excavation through diluvial sand, three indexes termed Simple shear strain, Moment index, and Shear index which are based upon the assumption that the ground above a shallow tunnel behaves as a kind of a continuous beam along tunnel alignment and transversally, characterize the settlement behaviour of the ground associated with tunnel advance as well as error function curve determines the shape and characteristics of transversal settlement trough.

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This paper discusses a numerical analysis of a crack propagation using fracture mechanics to evaluate a fracture crack induced by thermal stresses around a LPG storage cavern. J-integral is applied in the finite element method of thermal stress analysis for the calculation of stress intensity factor. A result of analysis on thermal stress fracturing tests of rock block shows that the crack propagation analysis is effective for thermal stress crack problem compared with a conventional method based on material mechanics. Crack analysis of LPG storage cavern indicates that a LPG leak out in case of a cavern with a small earth stress, so, storage cavern must be constructed at a deep rocks which tensile stresses isn't occured at the outside of the freezing zone.

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The excess earth pressure works on the buried pipes when they project into the surrounding soils due to the settlement of the soils. This paper describes the review of the formulas to estimate this earth pressure and the results of the experimental studies. The comparison of the observed earth pressures with estimated ones shows that the earth pressure on buried pipes under projection condition is most appropriately estimated by the formula in which the circular slip surface is assumed and Kötter's equation is solved along this slip surface.

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This paper deals with the mechanical properties of the Upper Pleistocene Clay which is deposited typically at the depth of 70 to 90m below sea level in the north areas of the Osaka Bay. The compression characteristics of the clay was investigated by carrying out a series of strain controlled drained triaxial tests including tests with K₀ condition. The test results indicate that the variation of pre-consolidation pressure increases almost linearly with depth as compared with a large scatter of the data obtained from standard oedometer tests. Also the effect of aging on the mechanical properties of the clay was studied by comparing the behaviour of undisturbed and re-sedimented samples during oedometer and undrained triaxial tests. The results indicate that there is a significant effect of aging on the clay behaviour.

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Highly idealized rockfill dam models are used for close examination of their failure mechanism under earthquake excitation. They have a symmetrically triangular configuration with regular arrangement of brass cylinders. The models are forced to failure by means of vibration, inclination or impulse applied at their base. The key step for their failure process is found to be an opening which develops at the deepest portion of the models. The opening can be attributed to a kind of buckling of the particles in a linear contact each other. As progress of the buckling requires a finite time duration, the earthquake failure is sometimes interrupted by the reversed direction of innertia force, suggesting great significance of acceleration period in such a failure.

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This paper presents a simple method to analyze the measured results of tunnel wall convergence and of displacement in the surrounding ground during tunnel excavation. This method is based on the assumptions that a circular tunnel is excavated in a two-dimensional ideal elastic body and that the vertical stress is equal to the overburden pressure. We can estimate easily (1) the directions and values of the principal genuine mountain stresses and (2) the elastic shear modulus of the ground from tunnel convergence measurements. In addition to the above (1) and (2), (3) the absolute movement of surrounding ground and (4) the approximate extent of the inelastic zone caused in surrounding ground can be estimated also in the case of the extensometer measurements.

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Many reinforcing methods and stabilization techniques of in-situ cut slope are fundamentally based on the statical conception, in which the internal forces of reinforcements at the place of crossing the (assumed) slip surface secure the stabilization of the cut slope, even when deformation of the slope is permitted.
In this paper, in order to clarify the mechanism of cut slope stabilization using comparatively short rock bolts which are same length and arrayed regularly, small scall laboratory tests of a vertical cut in a granular cohesionless soil and its simple analysis are studied. As a result, rock bolts make the soil around each of them perform almost a monolithic mass, and form the quasi-retaining wall made of in-situ soil.
This mechanism of rock bolts is the same of NATM which is a tunnelling method.

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This paper focuses on the following two topics: one is a new back analysis method using Kalman Filter-Finite Elements; the other is a determination of optimal location of observed nodal points for back analysis. A formulation is shown on Finite Element Method in conjunction with Kalman filter for two dimensional and plane strain problem, where Lamé's constants of non-homogeneous regions are solved. In the numerical procedure, the location of observed nodal points is determined taking into account the ‘sensitivity’ coefficients. These coefficients are defined as the derivatives of observed displacements by unknown parameters. The role and the meaning of ‘sensitivity’ coefficients in the Kalman Filter-Finite Elements are also discussed. The numerical performances for various problems in the field of geomechanics are described, and the applicability of the above procedure to some back analysis problems is examined on the comparison with the results by another algorithms.

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