| Transportation power,railway first.By the end of 2022,China’s railway mileage has reached 155,000 kilometers,most of which pass through mountainous areas.Therefore,the safety of the slopes on both sides of the railway is particularly important;The main reason for slope instability is caused by rainfall,long-term rainfall will increase the pore water pressure and saturation inside the slope soil layer,and the shear strength of the soil inside the slope is greatly reduced,which eventually leads to slope instability,and causes huge material losses of personnel,property and equipment and more serious traffic safety accidents,thus greatly affecting the normal operation of high-speed railway.In China’s slopes,soil-rock slopes are a more common and complex type of slope.Therefore,it is of great significance to study the seepage field,stability and reinforcement of soil-rock slopes by rainfall.In this paper,the slope beside the roadbed at DGK9+738～DGK10+012.5 of the high-speed railway from Jiande to Quzhou in Zhejiang Province is taken as the research object.The finite element analysis software midas GTS NX is used to simulate the changes of the seepage field,displacement and safety factor of the slope under the condition of rainfall.The prestressed anchor rod reinforcement is carried out for the conditions that do not conform to the safety standard of slope and the anchor rod reinforcement scheme is optimized.The main research work and achievements are as follows:(1)Convert the theoretical formulas of transient saturated flow and transient unsaturated flow;Summarize and compare slope stability research methods;The finite element solution method and convergence criterion are derived;The yield process of soil under the MohrCoulomb criterion is expounded,which provides a theoretical basis for the slope simulation calculation in the following paper.(2)Through the analysis of engineering data,the mechanical parameters and permeability coefficient of each soil layer of the slope are determined,and a three-dimensional slope model of the soil-rock slope is established;The initial seepage field,displacement and safety factor analysis of the slope under natural working conditions was carried out,and it was concluded that the slope was in a stable state under natural working conditions.(3)According to the local rainfall data,understand the rainfall situation in 22 years at the location of the slope,design six rainfall conditions,and analyze the changing trend of different rainfall duration,rainfall intensity and rainfall types on the seepage field,displacement and safety factor of the slope.Among them,working conditions 1～4: the rainfall duration is unchanged and the rainfall intensity is changed.The influence of different rainfall intensity on the seepage field and stability of the slope is studied.Working conditions 2,5 and 6: the rainfall remains unchanged,and the daily rainfall intensity is changed.The influence of flat peak type,back front type and front peak type rainfall on the seepage field and stability of slope is studied.The results show that the post-peak rain pattern has the greatest influence on the seepage field,the maximum displacement value and the safety factor of the slope,and the slope is in an unstable state under this condition,so it is necessary to strengthen the prestressed anchor anchor rod under the post-peak rain pattern.(4)In order to optimize the anchor reinforcement parameters of soil-rock slope,based on the actual situation of soil-rock slope engineering,the maximum axial force and safety factor of 12 reinforcement schemes,such as different anchor rod lengths,anchor rod incidence angles and row distances between anchor rods,are compared respectively.The comparative analysis shows that when the anchor rod length is 14.5m,the anchor rod incidence Angle is 15° and the row distance between anchor rods is 4m,the slope reinforcement effect is the best and the most economical.Compared with before reinforcement,the maximum sliding surface area is effectively reduced by this reinforcement scheme,and the maximum displacement value of sliding surface area is reduced by 16.67%.Safety factor value increased by 37.43%. |
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