喜家湾地震黄土滑坡形成机理

Study on the Formation Mechanism of Xijiawan Loess LandslideInduced by Earthquake

在喜家湾滑坡现场调查基础上,采集黄土斜坡的原状黄土和滑坡滑带土试样进行了室内试验,分析计算了滑坡土体震陷性和液化可能性;并结合滑坡发生前斜坡在地震作用下的稳定性分析及数值模拟,对该滑坡的形成机理进行了研究。研究表明,地震发生时,斜坡上部黄土产生震陷,结构破坏,下部泥岩面附近处于饱和状态的黄土在很短时间内产生了液化现象,坡体下滑形成震陷—液化复合型滑坡。

The Xijiawan landslide, a typical loess landslide triggered by HaiYuan Earthquake in 1920 located in XiJi county was investigated in this paper. In order to clarify the formation mechanism of Xijiawan landslide, a series of tests were conducted on the loess soils collected from the main body of slope and surface of rupture in Xijiawan landslide,the possibility of seismic subsidence and liquefaction potential were analyzed , and the works of stability analysis and numerical simulation were done. The results show that the formation mechanism of landslide is the complex of seismic subsidence – liquefaction. When the earthquake happened, the destroy of seismic subsidence occurred on the upper soil of slope. Meanwhile, the saturated loess at the vicinity of lower mudstone built up loess liquefaction instantaneously.