Experimental Study On Mechanism Of Loess Landslide Induced By Heap In Tianshui Area

In the northwestern part of China,the landform type is the loess Liangmao area,and the loess and mudstone formations are widely distributed,and the geological environment is relatively fragile.With the implementation of the western development strategy,many major projects have been carried out in the area.Due to the limitations of natural conditions,geological disasters have occurred frequently,showing great intensity,wide range,large number,and sudden,mass,and chain.The characteristics of disasters have seriously threatened the safety of local people 's lives and property,hindered social and economic development,and caused huge economic losses to the country.Therefore,in order to ensure the safe operation of the under construction and planned long-distance transmission lines in the northwest loess area,and to ensure the smooth progress of urban water conservancy construction,highway construction,and energy construction projects,it is of great significance to carry out research on engineering loess landslides under complex conditions.In this paper,the loess landslides generally developed in Tianshui area,Gansu,China are used as the research object.Through the methods of field geological survey,data collection,laboratory experiments and numerical analysis,the deformation and failure laws of loess landslides under the action of heap loading are studied to reveal the start of such landslide The main conclusions of the mechanism and movement characteristics are as follows:(1)The effect of the stacking load on the vertical stress of the slope body is greater,and the horizontal stress is less.;(2)The landslide triggered by heap loading and loess-mudstone contact surface will develop a shallow slip zone on the inner side of the sliding body.The cracks at the lower edge of the loading zone will develop downward and gradually penetrate through the cracks at the shear outlet until a shallow slip zone is formed.However,the loading triggers the compound landslide of loess and mudstone,and generally no new slip zone is developed inside;(3)Combined with physical model tests and numerical simulation calculation analysis,the tensile zone of the slope body first appeared in the plastic zone,the shear plastic zone appeared in the interior of the sliding body and the shear outlet of the original sliding surface,and extended toward the middle of the slope body;(4)Heap-induced landslides on the interface of loess and mudstone mainly experience three stages: stress redistribution stage under loading,slip belt formation stage,and overall failure stage.For the pile-induced loess-mudstone composite landslide,it is mainly divided into three stages: local revival of the old landslide,creep deformation of the slope body and overall deformation and failure of the slope.