三峡大坝左岸1^#～5^#厂房坝段稳定性是工程的关键问题之一。采用弹塑性块体元法对3^#厂房坝段的稳定安全度进行了研究，块体单元法是一种以块体单元形心的刚体位移为基本未知量的数值分析方法，它可以精确和方便地模拟岩体结构面，能够较好地解决非连续介质的力学问题。它在稳定性分析方面的正确性被室内模型试验所证实，两者的结果相当一致。文章最后给出应用该法分析三峡大坝3^#厂房坝段在多种工况下的稳定性分析成果。

One of the important problems for the Three Gorges Project is the stability for dam section No.1〜No.5 at left bank. The stability safety of dam section No.3 is studied with elasto — plastic Block Element Method (BKEM) in the paper. BKEM is a numerical analysis method. The basic unknown quantities of BKEM are the rigid displacements of the central points of block elements. Structure interface can be precisely and conveniently simulated in the method, and mechanical problem of discontinuous medium can be better. The correct ness of stability analysis of BKEM is proved with indoor model experiment and the two results are very consistent with each other. Finally, the result of stability analysis for dam section No.3 under several conditions is presented.