EVALUATION ON INFLUENCE OF THE PLIOCENE GYPSUM LAYER ON STABILITY OF DAM BASE AT A HYDROPOWER PLANT ON THE UPSTREAM OF THE YELLOW RIVER

A gypsum layer of 2 meters thickness lies beneath the riverbed at a hydropower plant on the upstream of the Yellow River.Gypsum is easy to collapse when encountering water.It is the least favorable rockmass for construction of the hydropower plant because of its weak engineering geological properties and low mechanical strength.This paper assesses impacts of dissolution of the gypsum layer on the stability of dam base and provides guidelines for minimizing or preventing such impacts.