Study On The Influence Of Slope Type Factors On Slope Stability And Sensitivity In Yan'an Area

With the increasing development of economic construction in the western region of China,the number of engineering construction projects carried out in Yanan area in northern Shaanxi is increasing.The unique loess landform has brought a large number of slope projects to the project construction activities.In addition to the factors,slope type factors composed of slope height,slope angle,and horizontal and vertical curvature are also important factors affecting the slope stability in the region.Based on the research background of landslides in Yan'an area and the engineering geological survey projects along National Highway 341,this paper takes slope type factors and slope body stability as research objects.Based on data collection,field investigation,in-situ test and indoor test,the design Orthogonal test combined with the use of GTS NX software to simulate the calculation of the slope failure of each scheme,to obtain the law of the slope failure caused by various slope factors.Using statistical correlation theory,using sensitivity coefficient method,orthogonal test analysis method and gray correlation analysis method to get the significance of each factor on the stability coefficient.Finally,combined with the example of Liujiagou No.1 landslide along National Highway 341,a plan for slope reduction and load reduction was proposed.The research results are as follows:(1)The types of landslide development in Yan'an area mainly include four types of landslides in the loess layer,landslides in the ancient soil surface,landslides in the loess-bedrock surface and landslides along the top of the Neogene red clay.Most of these landslides are mainly small and medium-sized,shallow,traction failure;(2)There are three types of regional slope failure,which are controlled by the lateral curvature of the slope direction: when the lateral curvature is concave,the failure develops from the shoulder to the middle of the slope;when the slope is convex,it occurs from the middle of the slope to both sides Destruction;flat slopes appear to be destroyed simultaneously.The longitudinal curvature and slope height in the inclined direction,and the change of slope angle will not affect the form of damage development,but will affect the height position and degree of damage development.The displacement of the destruction model is mainly x-direction displacement and is basically the same as the total displacement distribution.The y and z-direction displacements are small.The z-direction displacement can be divided into two parts: the upper displacement direction is downward and the lower direction is upward;(3)The longitudinal curvature-stability coefficient curve shows a parabolic shape with an opening downward,and has a unique extreme point.The longitudinal curvature-stability coefficient curve reaches a maximum value point when the longitudinal curvature is 0.The maximum value point is the minimum value point at 0,the stability coefficient outside the maximum value decreases slowly,and the stability coefficient within the maximum value fluctuates rapidly;(4)Through the comparative analysis of the sensitivity coefficient method,orthogonal test analysis method and gray correlation analysis method,the slope height and slope angle are highly significant for stability,and the horizontal and vertical curvatures are influential but not significant.The sensitivities are slope angle,slope height,longitudinal curvature and lateral curvature in descending order;(5)According to the actual situation of Liujiagou No.1 landslide,it is proposed to set a large platform of 8m at a position 2/3 away from the foot of the slope in the inclined direction,and a small platform with a width of 2 ? 3m in the remaining positions,a single grade of 0.8,flat slope;It is set along a circular arc with a radius of curvature of 270 m,and the stability of the slope body after excavation is significantly improved by numerical simulation.