Three Dimensional Behavior of Hollow Gravity Dam

Abstract

As a hollow gravity dam is a structure consisting of constituent blocks separated by transverse joints, it was considered to behave as a kind of a two dimensional structure. Thus, it is reasonable that many studies on design of hollow gravity clams have been carried out by employing the two dimensional theory or model tests.
It is planned to construct the Uchinokura hollow gravity dam at a narrow valley with steep side slopes and in such a case, some interaction of blocks takes place to generate three dimensional stress state although the hollow gravity dam is inherently a two dimensional structure.
The authors performed two dimensional and three dimensional model test, to obtain information on three dimensional behavior of the hollow gravity dam.
An investigation made on the three dimensional behavior of the hollow gravity dam according to the observations and analysis of the results of model tests is described in this paper.
The results obtained are as follows:
1. One of the features of the three dimensional behavior of the hollow gravity dam is the rotational displacement of the blocks on the side slopes in the plane perpendicular to the dam axis. This seems to be intensified as the side slopes of the valley becomes steeper.
2. Another feature is bending of the web coused by the shear force through the side part of diamond head. This couses a bending effect on each block of the dam.
3. The above two effects causes a complex torsional bending stress state in the blocks on the side slopes.
4. In a practical design, unexpected strong stress concentration will result if carefill considerations are not given in the determination of the shape of excavation line, joint treatment and the allocation of spillway or some other incidental structures.