川东红层缓倾岩质滑坡的演化过程及其识别标志探讨

DISCUSSION ON EVOLUTION PROCESS OF FLAT ROCK LANDSLIDE AND ITS IDENTIFICATION IN RED STRATA AT EASTERN SICHUAN

通过对典型案例的调查研究,总结提出了川东缓倾顺层岩质滑坡的变形演化阶段划分理论,并提出不同演化阶段下的识别标志特征。结论表明:(1)初期短距离启动阶段,斜坡后缘主要表现为深大裂隙;(2)中期槽谷扩张阶段,斜坡后缘主要表现为沟槽、拉陷槽或者斜坡具有汇水聚集发生剧滑的地形特征,如圈椅状地形、三沟环绕或双沟同源地形、后缘洼地地形等。(3)大型、特大型顺层岩质滑坡大多为斜坡二次、甚至三次启动滑动的结果,识别古(老)滑坡是圈定大型、特大型顺层岩质滑坡的重要途径之一。(4)在地调详查中,应特别注重对斜坡微地貌和后缘拉张破坏区的调查,重点排查初期短距离拉槽启动阶段及中期槽谷扩张阶段的隐伏性斜坡。本研究为区内滑坡的预测预防和大型、顺层岩质滑坡隐患点的判定提供指导。

Through the typical case investigation, this paper proposes evolutionary theory for gently inclined bedding rock landslide at east Sichuan. It further proposed the identification for different stages of evolution characteristics. The main findings are as follows. The first is the initial short-distance s ta r t-u p phase. Deep fissures are mainly showed after the ramp edge. The second is the medium-term troughs expansion phase. Trench and groove （or depression pull ramp of catchment aggregation and occurrence of drama slippery topographical featu res） are mainly showed after ramp edge. They include chair-like te r ra in , three-channel surround or homologous Shuang^ou terrain , as well as terrain trailing edge of depression. Thirdly, large to extra-large rock bedded slope landslide is mostly the result of twice or even three times of starting to sliding in slope. Identification of the ancient （ o ld ） delineation of a large landslide is one of the important ways large rock bedded landslide. Fourthly, in the detailed investigation of the geological survey, the survey on slope micro-topography and tensile failure area is focused specially. The investigation is focused on the early short-range and medium-term pull-start groove troughs expansion phase of the insidious slope.