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2013年7月22日,甘肃省定西市岷县、漳县交界处发生6.6级地震,地震诱发了约600余处地质灾害(隐患点),其中规模最大的是岷县梅川镇永光村四社西的两个相邻滑坡。本文对永光村西侧滑坡进行了多种手段的现场勘测,特别是在坡顶及坡底开展了高密度面波勘探,分析了该黄土滑坡成因及滑坡附近的地形、地层等因素。采用动力有限元法和强度折减法结合的方法分析该滑坡在地震荷载作用下的动力响应、滑坡动力稳定性的影响因素以及地震荷载与滑坡失稳状态之间的关系。结果表明,由于地震前的强降雨导致表层黄土的抗剪强度降低,在地震荷载作用下黄土层之间存在拉应力效应并导致崩塌滑动。
On July 22, 2013, an earthquake of magnitude 6.6 occurred at the junction of Min County and Zhang County in Dingxi City, Gansu Province. About 600 geological disasters (hidden danger spots) were induced by the earthquake. The largest one is Yongcun Village, Minhe Meichuan Town, Two adjacent landslides to the west. In this paper, a variety of means of site survey were carried out on the west side of the Yongguangcun landslide. In particular, high density surface wave exploration was carried out on the top and the bottom of the slope. The causes of the landslide and the topography and formation near the landslide were analyzed. The dynamic response of the landslide under earthquake loads, the influencing factors of landslide dynamic stability and the relationship between the seismic load and the landslide instability are analyzed by combining the dynamic finite element method and the strength reduction method. The results show that due to the heavy rainfall before the earthquake, the shear strength of surface loess decreases, and the tensile stress effect exists between the loess layers under the earthquake load and causes the collapse and sliding.