Abstract
In designing fill dams, one of the current major problems is how to successfully provide a contacting part for an abutment to avoid a fractured zone which is found to be large in scale in the adjacent riverbed. In other words, the problem is how to suitably cut the bedrocks and excavate a section along the axis of the dam.
This paper discusses this problem as a case study with a numerical analysis using the finite element method (FEM) and base friction model tests.
In the case in which a fractured zone has a width of 65 m at the riverbed, a base friction model test carried out and a nonlinear stress analysis performed using FEM. There have been two such cases taken up for studying bedrock excavated sections, and the contacting part is simply provided to avoid the fractured zone and to avoid the fractured zone with a step on hard rocks.
The results obtained from the aforementioned study can be summarized as follows.
1) Base rocks settle remarkably due to the fractured zone, and around the boundary of the fractured zone and the hard rocks, the stability of the dam body has a tendency to decrease.
2) When the contacting part is provided with a step on the hard rocks to avoid the fractured zone, it is desirable not be place the step on the hard rocks because tension stress induces in the hard rock under the step.
3) The base friction model tests are effective to clarify the properties of the ultimate displacement and fracture mode of the dam body.
