Researchers and Engineers are currently attempting to remediate earth dams to prevent damaging effects of potential seismic loading. The actual state of knowledge needs to be improved at least in the two following fields: soil properties and seismic response calculation techniques. Moreover, the effect of earthquake acceleration on the response of the dam needs to be further understood especially as far as amplification effects are concerned. In this paper, the assessment of the failure is given both from geotechnical as well seismic points of view. A comprehensive parametric study covering the effects of soil cohesion and soil friction angle on the values of yield accelerations is carried out. A dynamic factor of safety has been established as a function of earthquake acceleration. Furthermore, the outcomes on crest response spectra of input earthquake acceleration, soil shear wave velocity, and reduction of soil small strain shear modulus Gmax with induced deformations is deeply analyzed. Results are promising and will be a contribution to the geotechnical earthquake dam engineering domain.

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The Levees of Shinano River were subjected to many damages at Niigata Chuetsu Earthquake in 2004 as well as Tohoku-Pacific Ocean Earthquake in 2011. The damage of levees depends not only on the distance from the epicenter, but also on the soil profile of levee and its foundation. In this study, we classified the damage of levee into five types, and investigated the relationship the geological categorization and the seismic characteristics of the levee with the damage types. The natural frequency for multiple layers and the shape of transfer function were adopted as the seismic index, because the natural frequency can be express the seismic stiffness of levee. To obtain natural frequency of multiple layers, we carried out the linear elastic analysis based on multiple reflection theory using the results of standard penetration and laboratory soil tests. Those investigations of levee have already performed at each 1 km, for every main rivers managed by MLIT, therefore the new investigations are not required. However, the interval of 1 km is not enough for management length in Japan sea side region, because of its geological complexity compared with the Pacific Ocean side. To specify the representative levee length for one borehole logging, the geomorphologic data was considered. To estimate the damage rank, the influences of magnitude of ground motion should be considered. In this study, the multiple linear regression analysis, which the base acceleration, the natural frequency and the shape index of transfer function were adopted as dependent variables, and its explaining variable was damage rank, was performed to prediction of damage rank.

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The design of traditional culvert structures in Japan has not considered seismic stability, because such structures have not suffered terrible damage in past earthquakes. In recent years, however, the construction of precast arch culverts, which include hinges in the main body and are outside the range of conventional culverts, has been increasing. In this study, large-scale shaking table test using a strong earthquake response simulator was conducted to clarify the seismic behavior of a two-hinge precast arch culvert. Furthermore, the inner space displacement and the earth pressure of the culvert were measured in each construction stage. From the results, it was found that the seismic response of the culvert is governed by the shear deformation of surrounding soil; and thus, a seismic deformation method will be probably applicable to the aseismic design. However, the modification mode of the component did not change according to the banking height and the culvert did not behave as expected in the construction stage.

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Many embankment dams are constructed on active faults or in their vicinity and the effect of fault rupture propagation through these dams has been studied over the past two decades. However, of crucial importance is to pay decent attention to the post-faulting stability of the dams according to their response to fault-induced unequal ground displacement. In this study, two typical homogeneous and zoned embankment dams have been studied numerically when faulting occurs in their underlying bedrock during steady state seepage conditions. Unequal ground displacement of normal and reverse dip-slip faults, with various dip angles, are applied in multiple locations of the dam’s base. The results of the numerical analyses are studied regarding the variations of pore water pressures within the embankments. Thereafter, the dam’s stability after faulting is evaluated. The results show that reverse faults may cause general increase in pore water pressure values and, consequently, reduction in slope stability safety factors; whereas normal faults have less destructive effects on the general stability of the embankment dams.

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Japan is one of the most earthquake-prone countries in the world. Many structures suffered from the great damage in the past. Fortunately any gravity-type concrete dam did not collapse and was not a disaster for the downstream area. However, some damages of the dam body were reported after the earthquake. The most one is the increase of leakage from dam, which accounts 60% of the total damages. The gravity-type dam has many longitudinal and lateral joints in the body. The increase of leakage might be cased from broadened aperture of the joints. In this study, the behavior of the joints in the dam body is examined with the 3-D numerical model by the input waves having the different directions. It is found that the lateral joints at the maximum cross section have the broadened aperture when the wave is inputted from the axial direction, and that the lateral and longitudinal joins near the abutment behave to increase the leakage when the wave is inputted from the up and down-stream direction.

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Most of seasonally frozen regions are widely distributed in the northern part of China; a lot of high-speed railways have been built in these regions. Due to the seasonally frost Most of seasonally frozen regions are widely distributed in the northern part of China; a lot of high-speed railways have been built in these regions. Due to the seasonally frost heave and thaw settlement phenomena in the subgrade, the irregularity problem of railway lines will occur; this will become a great challenge to the strict control standard of Chinese high-speed railway. Based on the state detection of high-speed railway track and the in-situ monitoring of subgrade frost heave deformation condition in 2012-2013 and 2013-2014 periods, the typically rules of frost heave and thaw settlement in high-speed railway subgrade in the seasonally frozen region have been found out. Take a high-speed railway in the seasonally frozen region as an example, the frost depth of subgrade can be divided into two stages, the steadily rapid development stage and the two-direction thaw stage. The relationship between the in-situ detected engineering frost depth and the latitude,the frozen index and the naturally frost depth have been achieved. The amount of subgrade frost heave in winter is relatively low, and the distributed area is relatively narrow. The whole process of frost heave can be divided into five typically stages: the initially fluctuation stage, the rapidly developed stage, the gently developed stage, the fluctuated thaw settlement stage and the thaw settlement deformation stage. The spatio-temporal changing laws of frost heave deformation in each stage and the relationship to the foundation structure, the characteristics of filling material and the moisture condition have been pointed out. The frozen-thaw features of high-speed railway subgrade and the comparison results between two winter periods have provided important technology support to the construction, the operation and the maintenance of high-speed railway in the severely cold region.

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