天水锻压机床厂滑坡变形破坏机制及形成演化

天水锻压机床厂滑坡(1.4×106m3)发生于1990年8月11日,滑坡体主要由次生黄土组成,滑床为第四系黄土和新近系泥岩,滑坡沿黄土-泥岩接触面发生,属黄土接触面滑坡。通过野外调查和工程钻探对锻压机床厂滑坡变形破坏机制及形成演化进行研究,结果表明,该滑坡变形破坏方式表现为滑移-拉裂式,受区内二元斜坡结构控制,是在工程切坡和降雨、灌溉等诱发因素作用下形成;其形成演化经历了高陡边坡形成期→滑坡孕育期→滑动面贯通临界期→滑坡启动下滑堆积期→滑坡复活变形期等过程。该滑坡目前处于欠稳定状态,遇地震或强降雨等作用,极有可能再次复活下滑。研究成果可为该类滑坡的防治预警提供理论依据。

DEFORMATION MECHANISM AND EVOLUTIONARY PROCESS OF THE TIANSHUI FORGING MACHINE PLANT LANDSLIDE IN GANSU

The Tianshui Forging Machine Plant Landslide in Gansu Province happened on August 11, 1990 with a volume of 1.4×10⁶ m³. It is a loess interface landslide occurring along the loess/mudstone interface. The landslide body is mainly composed of secondary loess, and the slip bed is mainly composed of Quaternary loess and Neogene mudstone. The landslide is controlled by the double-layered structure of the slope in area, being induced by some factors such as engineering excavation, rainfall and irrigation. The research on the deformation mechanism and evolutionary process of the landslide based on geological survey and engineering drilling shows that the formation process can be divided as follow: the formation period of high and steep side slopes; the landslide incubation period; sliding surface through critical period; landslide falling and accumulating period; landslide revival and deformation period. Field investigation and engineering drilling indicate that the landslide is unstable at present. It can most likely revive and slide again if there is earthquake or heavy rainfall. The results can provide theoretical basis for the disaster warning of this kind of landslide.