Mechanical Behavior Of Modular Reinforced Soil Retaining Walls For High-speed Railway During Operation

In order to understand and grasp the long-term performance of the modular reinforced earth retaining wall,based on the Qingrong Intercity Railway reinforced earth retaining wall test section,field tests were carried out to study the structural behavior of the high-speed railway modular reinforced earth retaining wall during the operation period.Based on the actual working conditions,a corresponding numerical model was established,and the key factors affecting the long-term performance of the reinforced earth retaining wall were studied based on the wall type.The main work and results are as follows:(1)Briefly introduce the connection methods of the modular reinforced earth retaining wall wall and the reinforcement,including embedded type,pin type,connector type and return type,and analyze the typical retaining wall under different connection methods.Destruction mode.(2)Based on the Qingrong Intercity Railway Modular Reinforced Earth Retaining Wall Project,conduct field test research on the reinforced soil retaining wall during operation,monitor and analyze the post-construction earth pressure,strain of reinforcement,and retaining wall level The changing law of displacement and settlement reveals the structural behavior of modular reinforced earth retaining walls during operation.Six years after the completion of the construction,the strain of each layer of the reinforcement material showed a downward trend over time,and the decline was less than 0.88%;the maximum horizontal displacement of the wall was11.43 mm,which was 0.15%H(H is the wall height);the maximum settlement value of the wall top It is 46.77 mm and 0.60% H,which meets the requirements of the specification;the reinforced earth retaining wall reaches a stable state one year after the completion of the construction.(3)Using the nonlinear finite element software PLAXIS,a numerical model that can simulate the structural behavior of the modular reinforced earth retaining wall during operation was established,and the mechanical properties and behavior of the structure were studied and compared with the field test results.The results show that during the operation period,the simulated strain value of the geogrid is relatively close to the measured value.It is recommended to use the broken line obtained by the intersection of a straight line with an angle of 19° from the horizontal plane and a straight line with a distance of 0.96 H from the wall as the potential fracture surface of the retaining wall.;The simulated value and the measured value of the horizontal displacement of the wall gradually stabilized with the continuation of time;the part with the larger settlement of the retaining wall is located in the range of the load,and the settlement of the wall,the bottom of the wall and the foundation soil is smaller;and PLAXIS is used.The software predicts that the top settlement of the retaining wall 60 years after construction is 54.04 mm.(4)Based on the finite element numerical simulation,the factors affecting the deformation of the modular reinforced earth retaining wall during the operation period are studied.It is concluded that during the operation period of the retaining wall,the post-construction deformation under different factors gradually decreases with the passage of time.The law of wall deformation at each moment is basically the same;it is recommended to take the L/H of the long reinforcement(L is the length of the reinforcement)= 1.28,and the L/H of the short reinforcement = 1.03 is more appropriate;the position and size of the load and the reinforcement are proposed.Under the premise of a certain spacing,the main controlling factors affecting the deformation of the modular reinforced soil retaining wall after 20 years of construction are the elastic modulus of the filler and the length of the geogrid.