天水市水眼寨滑坡特征及稳定性分析

Characteristics and Stability Analysis of Shuiyanzhai Landslide in Tianshui City

摘要:

在对天水市水眼寨滑坡进行地质勘察和现场调查的基础上，结合区域环境研究滑坡的主要特征，分析地形条件、地层岩性、地质构造、地震、降水和人类活动对滑坡的影响，并利用GeoStudio计算软件，运用多种稳定性评价方法对滑坡静力和不同地震强度作用下的动力稳定性进行计算分析。结果表明，水眼寨滑坡属于黄土—泥岩滑坡，经过多期滑动，滑坡物质和滑坡体具有显著地平面分区性和剖面分层性，地层岩性和地质构造运动是其形成的主要内因，降水和地震是影响其稳定性重要外因。滑坡目前处于稳定状态，但未来环境变化会导致该滑坡稳定性降低，在Ⅶ度地震作用影响下该滑坡处于极限平衡状态，在Ⅶ度强以上地震作用影响下（＞0.15 g），该滑坡稳定性大为降低，存在复活的可能性。

Abstract:

On the basis of the geologic investigation and field survey，this paper studied the main characteristics of the 2013 Shuiyanzhai landslide；analyzed the influence of terrain conditions，formation lithology，geologic structure，earthquake，rainfall，and human activities on the landslide；and calculated the dynamic landslide stability of the analyzed formation under the simulated action of static forces and different earthquake intensities using GeoStudio software and a variety of stability evaluation methods.The results showed that the landslide originated in a giant loess of mudstone tractive type.Landslide material and landslide mass have significant regionalization in the plane and stratification in profile.Stratum lithology and tectonic movement are the main internal causes，whereas rainfall and earthquake are important external causes.The landslide area is currently in a steady state，but the stability can be reduced and even reactivated by environmental change in the future.The landslide is in a limited equilibrium state under a Ⅶ degree seismic action.Failures occurred in the region when horizontal peak ground accelerations （PGA）reached greater than 0.15 g.