建立重力坝坝基深层抗滑稳定极限状态函数是进行可靠度研究的第一步,对已有4种极限状态函数进行比较研究,探讨其合理性.研究结果表明:根据剩余推力法、被动抗力法及等K法表达式建立的极限状态函数计算得到的可靠指标是一致的,3种极限状态函数可统一表达为安全系数极限状态函数,而以上、下游块等可靠指标为约束条件的等β法高估了双滑块模型的失效概率,以此来评价坝基深层抗滑稳定的安全度并不合理. It is the first step to study the reliability of the deep foundation dam foundation with gravity dam foundation, and the four limit state functions have been compared to explore the rationality.The results show that according to the residual thrust method, the passive resistance method And the K-law expression established by the limit state function of the reliable indicators calculated are consistent, the three kinds of limit state functions can be expressed as the safety factor limit state function, and the above, the block and other reliable indicators for the constraints such as β Overestimating the failure probability of the double-slide model, so as to evaluate the safety of deep-slide stability in dam foundation is not reasonable.