黄土地震滑坡的触发类型、特征与成灾机制

Triggering types,characteristics and disaster mechanism of seismic loess landslides

基于现场调查勘探、无人机航测和大型振动台试验,系统研究了黄土地震滑坡的触发类型、特征与成灾机制。结果表明,黄土地震滑坡在空间分布、单体规模、致灾范围、平面形态、地形水文条件、地震动强度、土层厚度、与发震断层关系等方面具有显著特征。黄土地震滑坡从触发机理角度可划分为剪切型滑坡、液化型滑坡、震陷型滑坡三种类型。剪切型滑坡根据滑动面地层岩性可进一步分为黄土层内滑坡、黄土与泥岩接触面滑坡、切入基岩的切层滑坡;液化型滑坡可根据液化层位置划分为底部液化滑移型、表层液化泥流型、底-表层联合液化滑流型等。震陷型滑坡可根据坡体破坏形式细分为陷滑型、崩滑型等两种。本文可为黄土地震滑坡的风险评估与防控提供科学依据。

Based on the field investigation and exploration,unmanned aerial survey and large-scale shaking table tests,the triggering types,characteristics and disaster-generating mechanism of seismic loess landslides are systematically studied.The results show that the earthquake-induced loess landslides have their distinctive characteristics in spatial distribution,single size,influencing area,plane modality,topographical and hydrological conditions,seismic intensity,deposit thickness and relations to seismic faults.They can be classified into three types from the perspective of the triggering mechanism:shear landslides,liquefaction landslides and seismic subsidence landslides.The shear landslides can be further classified according to the lithology of the sliding surface strata into three types:landslides within a loess layer,landslides on the contact surface between loess and mudstone,and landslides cutting into bedrock.The liquefaction landslides can be divided according to the location of the liquefaction layer into three types:deep liquefaction sliding type,surface liquefaction mudflow,and combined deep-surface liquefaction type.The seismic subsidence landslides can be divided into two types of landslides,subsidence slide and avalanche slide,according to the damage modes caused by seismic subsidence.This study may provide a scientific basis for the risk assessment,prevention and control of loess seismic landslides.