Numerical Simulation Analysis Of Composite Soil Nailing With Anchor Beam In Earth Slope

Soil nailing,anchor and frame beams is commonly used for slope supporting technology.Combining with these three kinds of supporting methods,the new technology of anchor frame beams composite soil nailing is formed.Currently there is very little theoretical research on this new composite structure.Therefore,it is necessary to study it theoretically.With the homogeneous slope of fine grained fill soil under good geological conditions as the research object,the development of soil nailing and composite soil nailing is summarized in this paper firstly and then introduces the working principle of soil nailing and anchor and frame beam.Finally,using the finite element method and economic method to analyze the stability and economy of soil nailing and anchor + soil nailing and frame beam+ soil nailing and anchor + frame beam + soil nailing.The main contents and achievements of the study are:(1)Using the displacement and the safety factor which was obtained by ABAQUS finite element analysis software and Lizheng geotechnical software to analyze the stability condition of unsupporting and soil nailing and anchor + soil nailing and frame beam+ soil nailing and anchor + frame beam + soil nailing.The results are as follows: the excavation causes the slope position to increase and slide move downward.The effect of the four ways to constrain the slope position shift is: anchor + frame beams + soil nailing > anchor + soil nailing > frame beams + soil nailing > soil nailing > unsupported;The maximum axial force of the soil nail is: anchor + frame beams + soil nailing > frame beams + soil nailing > anchor + soil nailing > soil nailing.This indicates that soil nailing and anchor are beneficial to reduce the displacement of the slope and the frame beam can increase the maximum axial force of soil nail.(2)Taking Chongqing area as an example,by querying material price in the Chongqing project cost information online,calculating the economic cost of four supporting forms,They cost as follows: frame beams + soil nailing > soil nailing > anchor + frame beams + soil nailing > anchor + soil nailing.This indicates that the support cost of soil nailing is higher,and the support cost of anchor and frame beams is lower.(3)With anchor frame beam composite soil nailing as the research object,using the ABAQUS finite element analysis software to analyze the stability of the homogeneous soil slopes of fine grained soils in different conditions(including the length,angle and horizontal spacing of soil nailing and anchor).Analyzing the safety factor,displacement and axial force of each case and geting the optimal value of the parameter.The results are: The safety coefficient is the same as that of soil nailing or anchor,it has consistent trend and the safety coefficient is the opposite of the horizontal spacing between soil nailing and anchor.The optimum parameter value are: soil nailing angle is10?~15? and soil nailing horizontal spacing is1m~ 1.5m;anchor bolt angle is10?~ 15? and anchor horizontal spacing g is1.5m~ 2m.