基于强度折减法的土石坝稳定性分析及失稳判据选择研究

针对强度折减法分析土石坝稳定性的研究较少且失稳判据不统一的现状，基于ＦＬＡＣ３Ｄ建立某水库土石坝模型，用强度折减法分别计算该土石坝在正常蓄水位渗流稳定期及水位骤降条件下的稳定安全系数，同时针对强度折减法中三种失稳判据计算结果不统一的现象，分析坝体材料参数与失稳判据计算结果统一性之间的关系，并进一步探讨基于强度折减法的土石坝失稳判据的选择方法。结果表明:该土石坝在渗流稳定期稳定性较好，而水位骤降会导致坝坡稳定安全系数迅速减小；剪胀角和抗拉强度对强度折减法三种失稳判据的计算结果均有一定影响，计算中应重视其取值。

Analysis of the Stability Criteria and Instability Criterion of Earth Dam Based on Strength Reduction Method

At present the earth dam stability analysis by strength reduction method is scarce ,and the instability criterion is not unified .A two-dimensional (2-D ) numerical model was developed for the given earth dam by FLAC3D ,and three kinds of stability criteria to calculate the stability safety factor were discussed considering seepage .The safety factors of the earth dam were also calculated based on strength reduction method under the conditions of stable seepage and sudden drawdown of water level .However ,because of the different results given by different criteria in the same case ,the dila-tancy Angle and the tensile strength were studied for the impact of the result .The results indicate that the stability safety factor of the earth dam meets requirements in the case of seepage stability while decreases rapidly in the case of sudden drawdown of water level .And the dilatancy angle and the tensile strength have a certain influence on the three kinds of criteria ,so their value should be taken carefully .