心墙型土石坝一般以不透水料(粘土)筑成心墙,用透水料(如砂砾、石碴等)在心墙的上下游两侧筑成坝壳。当水位降落时,坝体中的水向水库反渗,产生促使坝坡滑动的渗透压力。因此设计中,需核算水库水位降落时上游坝坡的稳定性。在这种不稳定渗流情况下,最简单的方法是假定水位降落期间坝壳中自由 Core wall earth-rock dam generally impermeable material (clay) built into the heart, with permeable material (such as gravel, ballast, etc.) in the heart wall on both sides of the dam built into a shell. When the water level falls, the water in the dam reverse seepage to the reservoir, resulting in osmotic pressure to promote sliding of the dam slope. Therefore, in the design, the stability of the upstream dam slope when the reservoir water level falls needs to be calculated. In the case of such seepage instability, the easiest way is to assume that the free fall in the dam shell