Research On Creep Characteristics And Reinforcement Effect Of Soft Rock Of High-Speed Railway Foundation Under Water Soaking

In order to study the post-construction settlement law of the high-fill roadbed,this paper takes the typical soft rock of the Beijing-Shenzhen high-speed railway as the research background,using the self-made triaxial compression creep test device,the TAW-2000 rock triaxial testing machine and the GDS dynamic triaxial testing machine Carry out argillaceous sandstone creep characteristic test,uniaxial compressive strength test and triaxial compression test,using MIDAS/GTS NX finite element software to simulate and analyze the settlement evolution law of the reinforced roadbed.The main research results are as follows:(1)According to site design data and retrieve rock samples,carry out basic physical and mechanical properties test of argillaceous sandstone to determine the density,water content,free expansion rate and disintegration resistance index of the rock.The X-ray diffractometer was used to detect the rock samples taken to determine the phase composition and content of argillaceous sandstone,and the influence of mineral composition on the characteristics of free swelling and disintegration resistance of argillaceous sandstone was analyzed.(2)Use the self-made triaxial compression creep test device to carry out the triaxial creep test of argillaceous sandstone under water immersion,and study the creep deformation law of soft rock of high-speed railway foundation under the influence of water.Based on the free constraint conditions,the curve characteristics of the three-axis creep of the subgrade soft rock under different immersion times and load levels are analyzed,and the initial creep of the subgrade soft rock and the strength parameters and evolution rules after creep instability are determined.The creep model is promoted,and the test curve is fitted and the parameters are inverted.(3)Carry out rock uniaxial compressive strength and triaxial compression tests,study the deformation and strength characteristics of argillaceous sandstone under different C slurry content and water content,and reveal the strength and mechanical characteristics of argillaceous sandstone.The water blocking mechanism of argillaceous sandstone was analyzed,and the evolution equation of the basic physical and mechanical parameters of argillaceous sandstone with the change of grout filling rate was established.Using Mor Coulomb’s strength theory,the cohesion and internal friction angle of the argillaceous sandstone after reinforcement are determined.(4)Using MIDAS/GTS NX to perform numerical simulation analysis on the roadbed model,the settlement and deformation laws of natural,saturated and reinforced argillaceous sandstone under the weight of embankment and track slab are studied.The two-way relative train load is applied and the linear time-history operation mode is adopted to study the evolution characteristics of the displacement and stress field of the muddy sandstone embankment under the action of the train load.The distribution of the vertical displacement and dynamic stress is analyzed.