| Under the promotion of national strategic thoughts such as "One Belt And One Road" and "High-speed railway going global",the construction of high-speed railway has been further developed.High-speed railway projects in karst areas are also in full swing or have been put into operation.However,according to statistics,the completed highspeed railway lines have passed through the middle to strong developed section of karst for 4800 kilometers.Among them,the length of the section located in the highly prone area of karst collapse reaches more than 2,000 kilometers.With the increasing railway length in the karst area of China,the study of the influence of concealed soil holes in the prone area of karst collapse on the stability of railway subgrade and the disaster mechanism has become a scientific problem to be urgently solved.Taking the subgrade in the latent karst area of Shanghai-Kunming high-speed railway(Guizhou section)as the research object,the influence of karst collapse on the stability of subgrade under static and dynamic loads is studied by theoretical analysis,field test and numerical simulation,in order to provide theoretical basis for the prevention and control of karst collapse disasters.The main research contents include:(1)Combined with field investigation and relying on the engineering geological information,analyzes the shanghai-kunming high-speed guizhou karst section of geological structure,stratum lithology,landform,hydrology condition,karst landform and conjunctively tuning results morphology and distribution of karst development characteristics,analyzed the research area of subgrade worksite karst collapse disaster mechanism and the influencing factors and control.(2)In this paper,an in-situ test on train vibration propagation in subgrade section of Guizhou section of Shanghai-Kunming high-speed railway is carried out.The acceleration of environmental vibration caused by train operation is monitored.The propagation and attenuation laws of environmental vibration waves around the subgrade during high-speed railway operation are analyzed from time domain and frequency domain.(3)Based on ABAQUS software,the fluid-structure coupled three-dimensional finite element model for the stability analysis of soil tunnel subgrade under high-speed railway in karst area was established.The influence of significant factors such as different soil tunnel sizes,embankment filling heights,soil tunnel positions and groundwater level changes on the stability of soil tunnel subgrade and soil tunnel was calculated and analyzed by strength reduction method.(4)The three-dimensional finite element numerical model of high-speed trainballastless track-subgrade structure coupling in karst area is established,and the vibration influence of high-speed railway train vibration on karst environment is analyzed.The dynamic response of train vibration along the direction of subgrade depth and its influence on the stability of subgrade and soil tunnel are analyzed under different train axle load,train running speed,buried depth of soil tunnel,relative position of soil tunnel and subgrade,and dual track railway running in opposite direction. |
PDF Full Text Request