税湾地震黄土滑坡的岩土动力特性及其稳定性评价

黄土滑坡体的稳定性是一项重要的地质调查内容，需要结合区域地震地质条件进行评价。对天水市麦积区税湾某黄土滑坡体采用并行电法探测和数值模拟2种手段进行论证评价。通过并行电法对滑坡体进行精细分层探查，确定滑坡体的赋存状态及主滑面特征参数，精确构建税湾滑坡体的数值模型，进一步分析其在地震荷载作用下的动力响应特征；同时，采用多种方法计算滑坡体在自然状态、小震和大震3种情况下的稳定安全系数，其中利用强度折减法所得系数分别为2.942、1.99和0.683，结果表明，大震情况下该黄土滑坡体将发生滑动破坏。其过程为早期在滑坡体上部出现拉裂破坏、中下部出现剪切破坏，随着震波的持续加载，斜坡上下剪切应变高值贯通，滑面形成。采用现场探测和数值模拟相结合的评价方法及其所取得的结果，可为当地滑坡防治提供指导，为类似滑坡的稳定性评价提供参考。

Geotechnical Dynamic Characteristics and Stability Evaluation of Loess Landslides in Shuiwan Earthquake,Tianshui, Gansu

The stability of loess landslide is quite important in geological investigation, which needs to be evaluated in combination with regional seismic conditions. This paper evaluated a loess landslide in Shuiwan, Maiji District of Tianshui city by means of parallel electrical method and numerical simulation. The parallel electrical method is to explore the fine layers on the landslide mass and determine the occurrence state and the parameters of the main sliding surface in order to accurately construct the numerical model for the landslide mass in Shuiwan, and further analyze its dynamic response characteristics under the earthquake load; at the same time, various methods are used to calculate the stability safety factors under three circumstances of natural state, small earthquake and large earthquake. The coefficients obtained from the strength-reduction method are 2.942, 1.99 and 0.683, respectively. The results show that slide failure happen in loess landslide mass under large earthquake. The process is that the upper part of the landslide is cracked in the early stage, and the middle and lower parts are sheared. With the continuous seismic waves, the shear in the upper and lower slopes is connected, and the sliding surface is formed. The results of on-site detection and numerical simulation provide guidance for landslide prevention and reference for the stability evaluation of similar landslides.