Recently highly developed methods such as nonlinear analyses by the finite elemennt method are used for the stress analyses of the foundations. But there remained some unknown problems such as that we can not explain the reasons why the stresses in deeper parts of foundations are in hydro-static states by these analyses.
In this paper, it is asserted that there are two sorts of nonlinear deformations caused by relative movements between component elements of foundation, one is the nonelastic deformation with shrinkage and the other is one with dilatation and it is shown that by taking into consideration the redistributions of stresses by these nonlinear deformation, the forementioned problems can be explained.

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The interaction among seepage, stress and stability of an earth dam during reservoir filling is investigated by a finite element method. A saturated-unsaturated seepage analysis is superposed on a stress-deformation analysis to evaluate the effect of body forces such as seepage force, buoyancy and surcharge due to saturation on the behavior of effective stresses within the dam. By using stress levels mobilized in the finite elements, values of safety factor along a circular slip surface are calculated to assess the stability of the dam during seepage. The strength of soil is described by Mohr-Coulomb' s failure criterion.
Numerical results show that the stability of the dam is influenced by the speed of reservoir filling and the moisture condition at the start of resevoir filling.

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Recently many dams are constructed on soft rocks due to increasing demands of flood control and city water supply.
Conventional rock classification cannot be applied to soft rocks in a direct way since the spacing and the condition of discontinuities are less important factors than the hardness in the rock classification.
The authors have developed the Pendulum Rebound Tester which can evaluate the hardness of soft rocks quantitatively. After a comprehensive study using the Pendulum Rebound Tester, it is found that the Tester is well utilized in the soft rock classification.

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Along the Ootani Dam reservoir, there are 11 places to be suspected or to be landslide. These places are classified according to the landslide level against filling water level and activation of landslide. From the result of classification 7 places ware taken measures to be safe, 8 places were arranged monitoring equipment for measuring landslide behavior and the safety of landslide during filling were confirmed through the test filling. Nunokura landslide is most large in these places and again moved landslide from the previous year of filling, which slided two years ago.
In this reports, behaviors of landslide Nunokura Landslide from the begining to the test filling through the construction of measure of landslide and the measures of landslide are described.

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The roller compacted concrete (RCC) construction method, which was developed in the United States, is a popular dam construction method in the world. Since the construction technique and the quality of concrete in this method are based on those of (fill-type dam), construction period is shorter and the total cost is lower than those of other construction method. However, the dam concrete constructed by this method does not have enough connective materials and it tends to have cracks so that water often leaks. Therefore, a lot of efforts to inprove this method has been done. In this paper, we review the development and improvement of the RCC construction method, and then, discuss an ideal dam construction.

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