强震作用下低角度黄土斜坡滑移的复合机理研究

针对 192 0年宁夏海原大地震 (Ms =8 5 )时固原清水河Ⅳ级黄土台塬所发生大面积低角度黄土斜坡滑移现象及其种种特征 ,经过现场勘察、室内试验及理论推导 ,提出了一种强震作用下低角度黄土斜坡滑移的复合机理---位于第一层古土壤层下部饱和黄土和砂土震动液化 ;位于其上部黄土层受地震力和液化的双重作用而呈现波浪状地貌 ,进而部分黄土体解体、斜抛、粉尘化和远程运移而形成黄土流或黄土瀑布。用笔者提出的滑距公式对滑移体的滑距进行了计算 ,效果良好

A study on compound mechanism of earthquake-related sliding displacements on gently inclined loess slope

Due consideration has been paid to the characteristic features and phenomena of the tremendous sliding displacements triggered by 1920 Haiyuan earthquake (M s =8.5) on gently inclined loess slope which is located in the loess terrace 4 along Qingshui River,Guyuan County,Ningxia Autonomous Region of Hui Minority, China.Based on the features and phenomena such as high sliding speeds,long traveling distance,loess falls,wave form topographic surfaces and liquefaction,a compound mechanism is presented with the help of field exploration,mechanial and dynamic tests of soil and computed results.That is,saturated loess under the first fossil soil liquefied,and the upper loess produced mass disintegration oblique projection collision between loess blocks,pulverization and loess fall.The traveling distance of gently inclined loess slope is calculated with the author’s formulae.The computed results quite agree with the evidences in field.