Study On The Formation Mechanism Of Mudstone And Crushed Earth Landslide In Xining City

Xining City is located in the Huangshui River valley and the hills edge of the region,for the hills and valleys plains,unique topography,geological structure and other geological environment,making Xining City,a variety of geological disasters.The results show that there are 49% of the total landslides in the Xining area,73.1% of the total landslides in the recent mudstone landslides,and 10% of the new crushed earth landslides account for 14.9% of the landslides and become a threat to human life and property.One of the major geological disasters.Therefore,the study on the genesis of mudstone and crushed earth landslide in Xining City can provide reference for the evaluation,analysis,early warning and prevention of landslide geological hazards in Xining City,which is of practical significance.In this paper,the mudstone landslide represented by Zhangjiawan brick factory landslide is selected as the object of study,and the landslide model and model mechanics are determined by field landslide survey and existing investigation report.Parameters,combined with FLAC3 D strength reduction method and SLIDE limit equilibrium method,the typical mudstone and gravel landslide in the natural and saturated conditions to make a comprehensive system of stability and genetic mechanism analysis.The following are:(1)Xining City,geological disasters,a total of 67 landslides,according to the nature of the slide can be divided into soil landslides,rock landslides,landslides three types of landslides,of which rocky landslides mainly to Tertiary(R),chalk(K)mudstone,sandstone and gypsum rock,accounting for 73.1% of the recent landslide;gravel soil landslide formation rock are Paleogene(E)mudstone,sandstone,gypsum rock formation,lithology is mainly debris Rock and salt minerals accounted for 14.9% of the total number of landslides.(2)Xining mudstone and crushed stone landslides,under the influence of tectonic movement,controlled by the Beichuan River West Bank fault,Huangshui River fault,Nanchuan River fault,sand Tangchuan fault zon(3)Mudstone and crushed stone landslide causes mechanism: Zhangjiawan brick mudstone landslide,due to the trailing edge of the steep slope under the influence of self-stress in the formation of cracks,the development of the rock within the joint fissure surface to become the advantages of cracking and shear,Precipitation has provided the infiltration channel,so that the upper part of the lower edge of the loess pore water,water content greatly increased,destroying the stability of the landslide,the final landslide collapse occurred collapse;Fujiazhai gravel landslide,due to Huangshui River Of the rapid cutting down the slope of the loss of salt increased,and the mudstone itself softening characteristics of the water is strong,deformation can not easily accumulate,the slope will be a small form of collapse in the form of continuous release of energy and piled on the foot of the slope,the formation of the slope of the existing The characteristics of this particular material,in the concentrated precipitation and other conditions under the slope of the salt constantly released,and in the relative formation of the sliding layer of the shear layer,and ultimately produce landslides.(4)The results show that under the condition of natural and saturated conditions,the stability coefficient of landslide in Zhangjiawan brick factory is 1.290,1.160,respectively,which indicates that the whole landslide is in steady state,and the strength reduction method and limit In the comparative analysis of the equilibrium method,it is concluded that the monitoring point A is in a state of instability at any time in the three monitoring points,and the stability of the monitoring points B and C is good,but the factors such as artificial excavation slope and heavy rainfall are excluded The overall stability coefficient of Fujiazhai landslide is 1.110 and 1.080 respectively,which indicates that the whole landslide is in steady state,and the strength reduction method and the limit equilibrium method are compared and analyzed.The results show that the landslide is in the stable state,,The stability of the central part of the landslide is poor,and it is a steady state at any time.This has a direct relationship with the special lithology and precipitation.