Research And Numerical Analysis On The Composite Support Structure Of High Cut Slope

With the construction of railways,highways and other projects advancing to mountainous areas in recent years,many slopes have been formed,and the safe stability of slopes engineering is particularly important.In the stability analysis of the actual slope engineering,the effect of the support structure on the calculation of the safe stability of the slope is not considered or simplified,in fact,the support structure has a great influence on the local stability of the slope,and the influence of the support structure on the local stability of the slope is ignored,the result will have a large deviation,which will easily lead to improper design.In response to the above problems,this paper relies on the Xingquan railway graben high slope work site,based on indoor tests,theoretical analysis,field monitoring,numerical simulation analysis and other methods to study the force and deformation distribution law of the graben high slope under composite support,assess the effect of composite support structure on slope stability and structure reinforcement,and propose the optimal design method of the graben high slope support,the main research work and the main conclusions and The main research work and the main conclusions and understanding reached are as follows.1.Based on the experimental study of physical and mechanical properties,the <9-2> soil layer has 65.48% of powder particles and 17.46% of clay particles,while <W4> and <W3>are dominated by sand and powder particles and also have less clay particle content.The particle distribution of the three soils is relatively heterogeneous,with a relatively large range of particle size variation and good particle gradation.In the consolidation and drained triaxial shear test,they showed strain hardening characteristics,and there was no obvious peak strength and softening deformation curve.2.Combined with the Winkler model of the elastic foundation beam to calculate the internal force of the frame beam,and according to the field force characteristics of the anchor cable-anchor frame beam,the calculation method of the distribution coefficient of the nodal force of the frame beam considering all the loads was proposed,and co MPared with the numerical simulation to verify;and based on the limit analysis upper limit method,using the logarithmic helix damage model,the power of gravitational work and the internal energy dissipation rate of the high side slope system of the road graben were derived.The safety factor calculation formula was proposed and verified by co MParing with the numerical calculation results.The theoretical calculated value is 1.483 and the numerical solution is 1.57.3.Based on the Xingquan railway site,a long-term monitoring test of the high slope of the road graben was carried out to obtain the characteristics of the deep displacement of the slope and the force of the anchor support structure,and it was found that the displacement of the slope and the force of the anchor structure were closely related to the construction of the slope,and the displacement of the slope and the force of the anchor were larger when the adjacent slope was under construction,which was compared and tested with the numerical simulation,and the reinforcement effect of the composite support structure was evaluated.The effect of the composite support structure is evaluated.During construction,the stresses at 1m at the end of the anchor rod and 4m at the middle of the anchor rod are higher,and the stress at the burial depth of 7m at the end of the anchor rod is more stable and maintained at a smaller value.4.Numerical simulation software is applied to analyse the displacement and deformation characteristics of the slope under graded excavation,during excavation,the displacement of the slope is composed of unloading rebound of soil and soil slip,the main body of the slope is mainly inclined rebound,the maximum horizontal displacement is 2.46 cm,and the top of the slope has a small amount of slip in the inward direction,the displacement is 9.4mm,which is small compared with the displacement of the main body of the slope.5.The average seepage depth of the slope can reach 6m when the slope is subjected to rainfall under storm condition(150mm/24h),and the maximum surface horizontal displacement of the slope is 1.5cm under the non-rainfall condition,3.081 cm under the rainfall condition,and 2.59 cm under the rainfall condition of the support,indicating that the timely implementation of composite support structure measures can effectively limit the displacement deformation of the slope caused by excavation and rainfall,and It effectively improves the anti-slip stability of the slope.6.The variable characteristics of the horizontal displacement,vertical displacement and shear strain of the slope before and after supporting under natural conditions and heavy rain conditions(150mm/24h)are co MPared and analysed,and the distribution law of the axial force of the anchor cable and the internal force of the frame beam are analysed to provide reference for the engineering design.For the frame beam,the calculated bending moments and shear forces are relatively large at the nodes,and negative bending moments appear in the middle of the beam span.The results show that there is little difference between the results of the theoretical method and the numerical simulation,and the curve trends are generally consistent,indicating the applicability and accuracy of the theoretical method.