Study On Formation Mechanism Of Landslide Controlled By Soft Rock In Coal Measure Strata Of Shanxi Province

The coal measures in Shanxi Province are developed and widely distributed,and the terrain in Shanxi Province is fluctuating.With the increasing activity of human production and life,people are mining,building houses and factories in mountainous areas,which has caused many geological disasters of landslides in Shanxi Province,which seriously restricts the economic development of Shanxi Province and affects the safety of people's lives and property in Shanxi Province.Based on the experience of engineering practice of this type of landslide,this paper selects typical case landslide,one landslide in East Mountain of Taiyuan in Central Shanxi,one landslide in Luliang Linxian County in Western Shanxi Province,Linfen in southwest Shanxi Province,based on the past engineering practice experience of this type of landslide The engineering geological conditions of a landslide in Xiangning and a landslide in Zizhou,Jincheng,southern Shanxi Province are analyzed.The mineral composition of the slip zone soil is analyzed by X-ray diffraction test,the free expansion rate test is used to analyze the swelling characteristics of the sliding zone soil,the mechanical properties of the sliding zone soil are analyzed by slow shear test,and the genesis mechanism of the soft rock landslide in Shanxi coal series is comprehensively analyzed.It is the same type of landslide in the province The main research contents and achievements of this paper are as follows:(1)The paper discusses the general situation,shape,scale and development of landslide in four typical cases in the province.According to the characteristics of the water absorption softening and expansion sliding surface smoothness of the landslide slip zone,the X-ray diffraction analysis is carried out on the landslide slip zone soil,and the main mineral composition of the soft rock sliding zone of coal series is clay mineral,which is mainly Mongolian Desalts,illite,kaolinite,chlorite and clinopyrochlore.(2)Combined with the qualitative and quantitative study of the soft rock landslide slip zone soil in coal series and the micro characteristics of clay minerals,it is concluded that the clay minerals have unique layered structure,among which montmorillonite has the highest water sensitivity,and the water absorption is prone to longitudinal expansion,and it is easier to slide along the mineral structure layer.(3)The free expansion rate and slow shear test were used to analyze the physical and mechanical properties of the soil in the sliding zone.It was concluded that the free expansion rate of the sliding zone soil and the montmorillonite content in the sliding zone soil were positively correlated.With the increase of water content,the cohesion and internal friction angle of the soil decreased,and the reduction rate was positively correlated with the content of montmorillonite and the free expansion rate of the sliding zone soil.At the same time,the failure mechanism of the sliding zone soil is analyzed from the micro point of view.It is concluded that the layered structure molecules are arranged in the direction of shear force and the failure mode of the sliding zone soil is occurred along the direction of the structural layer.(4)The factors influencing landslide occurrence are analyzed,and the results show that the stability of landslide is affected by topography,stratum,water and human activities.The paper classifies the soft rock landslide of Shanxi coal series,analyzes the different types of soft rock landslides of coal measures,and analyzes the stress modes of the sliding zone soil,and obtains the cause mechanism and the starting mechanism of different landslides,which provides the theoretical basis for the soft rock landslide of Shanxi coal series.