Acoustic emission (AE) characteristics for rock grouting, which have been obtained from several dam sites, are studied, regarding the relationship between AE energy and rock behavior. In situ monitoring tests were carried out for three different rock types and some injection conditions using four to six channels AE acquisition system. Hydrofracture originated due to the injection pressure can be characterized by the AE energy parameter, that is, the deformation energy accumulated in the rock mass during pressurization process is proportional to the AE energy and also relates to the injection amount increase accompanied with the crack enlargement.
As a result, grout injection evaluation technique is proposed based on the AE multi-parameter method and, its effectiveness is clarified through the sampling data.

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Discontinuous Deformation Analysis (DDA) was developed by G. H. Shi and RE. Goodman. It solves a finite element type of mesh where all the elements are isolated blocks and bounded by pre-existing discontinuity under kinematic conditions of dynamic and quasi-static motion. The authors developed elastic-plastic yield criteria of Drucker-Prager associated constitutive laws, rock-bolt and connected element and improved penalty method for block penetration. The developed methods are applied for the stability of rock slopes, tunnels and underground openings with different joint sets models and rock blocks test models. Since, these methods are applicable for the discontinuous rock mass models under many analytical conditions in theoritical and the results show validity for practical use.

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This paper describes the coupling analysis of thermo-mechanical consolidation and its discretization method to simulate the seepage flow due to heat and deformation of nuclear waste storage on jointed rock mass by finite element method. The authors followed basic equations presented by Ohnishi et al. (1986) and an anisotropic stress-strain and permeable constitutive laws are employed for combining arbitrary oriented joint sets by compliance matrixes (T. F. Cho, 1988). Four node standard iso-parametric finite element as Sandhu 1-1 type with reduced integration and scaling method are employed for the stabilities of numerical calculations. The results of two dimensional rock mass models with combining arbitrary oriented joint sets show that the direction of fluid flow is followed along the joint sets, and those are seemed to be clearly explained of the influence of joint orientations.

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It is not easy to know shearing resistance parameters c_d and ∅_d of compacted gravelly soils in field because of difficulty in getting the undisturbed samples for the laboratory test and also in performing the in situ shear test. In order to estimate shearing resistance parameters c_d and ∅_d of compacted gravelly soils in field from shear test of compacted soils in laboratory, the authers carried out shear tests (∅=150mm, h=100mm) with change of the gradation and the maximum grain size of compacted soils, and compared with the results of direct shear test in field using the 300mm×300mm×180mm shear box. From a series of laboratory tests using Samples I (cut off larger particles simply) and Samples II (replaced larger gravel-particles with smaller gravel-particles of the same weight), it is known that in situ strength parameters c_d and ∅_d of gravelly soils can be estimated reasonably by laboratory tests with a few kinds of samples I.

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The present paper develops for determination theory of initial stresses in isotropic or anisotropic elastic rock masses utilizing stress concentration of two neighboring boreholes, and describes a method determining five stress components (σ^∞_x, σ^∞_y, τ^∞_xy, τ^∞_xz, and τ^∞_yz) of in-plane and out-of-plane against the borehole axis (z-axis) among six components that are included in three-dimensional initial stress condition. Furthermore, some numerical results of high accuracy of sensitivity coefficients along the wall surface of the boreholes are shown and the concrete calculating method of initial stress components using these results is given.

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A method is presented for equi-linearized seismic response analysis of multi-layered ground including frequency dependent effect of shear modulus and damping on ground motion amplification. The frequency dependent equivalent strain in proportion to the Fourier amplitude of shear strain time history is defined for evaluation of shear modulus and damping factor depending on the frequency contents. The method is examined in the strong motion array records and minutely serveyed soil profile at array observation station located at very soft ground. Superoprity of the presented method to the conventional equi-linearized method is demonstrated especially in case of strong ground motion level and soft ground condition.

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In order to estabilish a method of estimating the long term settlement of highty organic soil overconsolidated by preloading, a series of laboratory and field measurements were carried out. Observation of ground movement during preloading and unloading indicate that primary settlement occurs first and then unloading makes the ground swell. Afterwards, secondary settlement occurs with a liner relationship between settlement and the logarithm of time.
Based on these findings, a method of estimating the amount of swelling and secondary settlement was established empirically for practical use. The proposed formulas make use of overconsolidation ratio, water content, duration of loading, and soil data (initial pore ratio, thickness of settlement layer, etc).

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A series of laboratory cone penetration tests using a calibration chamber are conducted on different types of cohesive soil to study the effect of various factors such as plasticity index, rigidity index and strain rate on cone resistance. It is found out that cone resistance increases with penetration rates. An attempt is made to predict cone resistance theoretically by incorporating the strain rate effect into the theory of cavity expansion. The theory compares well with the observation. It is shown that the effect of strain rate is very similar to that of rigidity index.

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Tunnel model test and simulation analysis are performed to establish the soundness evaluation method for a countermeasure for the tunnel lining with adjacent construction and deformation.
We have successfully developed tunnel lining test units that can express the ground-lining interaction and three-dimensional behaviors, then various model tests were carried out. We discuss about effects of the various parameters on the tunnel lining model deformation behavior in this paper.

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Most of existing tunnels have structural defects, such as lack of the thickness in the crown and presence of an opening behind the lining on account of its construction. We have carried out a model test and a frame analysis of influence of the defects on the lining behavior and effects of the inner reinforcement and backfill grouting on the tunnel lining.

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This paper presents the results of triaxial compression and extension tests on compacted Kaolin clays under two kinds of constant confining pressures and suction. The test results are uniquely arranged on “Extended Spatially Mobilized Plane (Extended SMP)” with a parameter of σ₀(=c·cot∅). These are the same results when the test results of sands and normally consolidated clays are arranged on the original SMP. And it is concluded from these results that the concept of “Extended SMP” can be applied to the shear behavior of unsaturated soil with constant suction under axisymmetric stress states. The applicability of this concept is the same to the other frictional and cohesive materials like cemented sands and overconsolidated clays.

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Summary of an in-situ grouting test and a digging survey for cement milk and cementwaterglass suspension with various grain sizes into the natural ground are presented. The fine sand in the ground has been considered as the more difficult grouting, having a coefficient of permeability of the order of 10^-3cm/sec. The relationships between the engineering properties as both permeability and strength and the pore size distribution in the hardened sand are examined. The micro structures of these sand are also determined by means of an electron microscope and a mercury intrusion porosimeter.

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Terre Armee method has a feature that walls are easily deformed. The investigation on relationship between filling materials and wall deformation indicates that wall deformation is greatly influenced by a filling material, namely, it is affected by fine fraction content, natural water content. From these results, a proposal is given with regard to an applicable range of the Terre Armee filling material considering wall deformation, which is different from that of conventional filling materials.

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A numerical method of seepage failure using a non-linear kinematic hardening rule is proposed. The effectiveness of the analysis is confirmed through the comparison with numerical results and existing equations. By earring out several cases of calculation, it is found that the critical hydraulic gradient depends on the raising rate of water level, coefficient of permeability and the degree of saturation of pore water. Based on the comparison between elastic analyses and elasto-plastic analyses, it is found that the elasto-plastic analysis can predict the deformation of ground and area of failure better than elastic one.

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Chemical grouting is used as an auxiliary method when underground structures are constructed in large cities. However, it is difficult to evaluate the grouted area by chemical grouting. To solve this problem, we note that electrical resistivity of chemical grout is much lower than the resistivities of ground and groundwater, and investigate the possibility of evaluation of grouted area by the resistivity tomography. Tn this study, the formula, which can express the relation between the resistivity changes before and after grouting and the grout/void ratio, was derived from the electrical-resistivity models of saturated sand and grouted sand that were already proposed. Furthermore, the evaluation method of grouted area by this formula was proposed. The validity of this method was shown by the comparison of the grouted area confirmed in model tests and the result of the evaluation proposed.

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The grading equation is applicable to other granular soils of various types, including of course weathered residual soil like decomposed granite soil. However, the proposed equation is the grading equation of discrete distribution type. Therefore, in this study, an attempt was made to transform the equation from the discrete type to the continuous distribution type, and a grading equation of continuous type was derived. By comparing the continuous type equation with the main grading equations, it was found that this equation had a greater scope of application.

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An optimal design method is presented for dewatering a excavation site. It predicts the optimum number of deep wells, their locations, and the rate of pumping needed to maintain ground water levels below specified elevations at steady and unsteady state. In our proposed method a linear programming method is used to determine the pumping rate at steady state and AIC is used to suggest the optimum deep well locations. This is accomplished by including the finite element analysis of two-dimensional steady seepage flow. Nonlinear least-squares algorithm incorporating finite element analysis of unsteady seepage flow is used to compute the pumping rate required to reach ground water levels below appointed elevation in a prescribed time. The method is applied to several examples of dewatering for a large excavation site in unconfined aquifer models.

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We propose an identification procedure of distributed parameter systems using the data of plural pumping tests. This procedure is based on the extended Kalman filter algorithm (Bayesian estimation). After the observational data of a pumping test are used to identify the spatially distributed hydraulic conductivities, the estimated values and the covarience matrix are updated iteratively with the observational data of the next pumping tests. The proposed procedure is verified with the simulated data in a model of a groundwater system, and the results are found to be reasonably accurate. Finally, we also demonstrate that the groundwater flow can be predicted with the estimated values and the covariance matrix.

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To investigate the reliability of the soil parameters predicted by flat dilatometer test, several documented data have been reviewed from sites in Europe and Southeast Asia as well as published data from Japan. The results of this review have shown that the equations proposed by Marchetti provide reasonable estimates of the in-situ undrained shear strength. However, some discrepancies were observed between laboratory results and DMT results about overconsolidation ratio and coefficient of earth pressure at rest. To this end, modified equations estimating the both soil parameters are proposed. In addition, a new correlation has been proposed to estimate N-values from flat dilatometer test.

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In order to assess the stability of tunnels, Sakurai proposed a method called Direct Strain Evaluation Technique (DSET). According to this method, strain occurring in rocks around tunnels is compared with its allowable value, and if the occurring strain is still smaller than the allowable value, tunnels are deemed stable. Considering that the failure of materials can be evaluated in terms of the maximum shear strain, this study defined critical shear strain as an allowable value for the maximum shear strain. The critical shear strain must be determined by a torsional shear test. However the test is often too complex and time consuming to operate. In this paper, there fore, it is demonstrated that the critical shear strain can be determined from uni-axial or tri-axial compression tests which are commonly used in engineering practice.

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This paper deals with the settlement of an embankment that is constructed on soft ground. The settlement prediction method, that uses the settlement observed data under construction, is proposed in this paper. The primary and secondary compression and their proportions after the extra-fill is removed can be predicted by this method. This method was applied to some actual observations. It was examined whether this method can be utilized with the practical design and the site's works.

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