Simulation Study Of Surrounding Rock Deformation In Shallow-buried Tunnel Simulation Study Of Surrounding Rock Deformation In Shallow-buried Tunnel

With the rapid development of transportation infrastructure,tunnel construction has become an important link to improve the transportation network,and is the main way to improve the mountain transportation network.Now,the tunnel construction in the mountains,the terrain is very steep,it is subject to the tunnel excavation,often face many terrain geological problems,such as the mouth of the cave bias instability,crushed surrounding rock of shallow buried is easy to collapse,can not predict the karst mud and water inrush and other all kinds of complicated situations,for tunnel safety construction has brought great threat,directly cause large economic loss and a certain degree of delays,is more likely to cause casualties.Therefore,it is of great significance to study the deformation of surrounding rock and the supporting method of surrounding rock in tunnel construction.Based on the new highway Taihu interworking in the north of Huzhou and connecting engineering contract section 2 the Huchang tunnel as the research object,aiming at the mouth of the cave of shallow buried tunnel construction under bias,using MIDAS GTS NX software tunnel excavation model is set up,by setting the different support parameters,the thickness of sprayed concrete,steel arch span and excavation step away from the influence on the deformation of surrounding rock,combined with the tunnel monitoring measurement technology,the measurement of dynamic data of surrounding rock compared with the data from simulation analysis,summarizes the law of the surrounding rock deformation,for the mouth of the cave of shallow bias tunnel excavation provide certain guidance.The deformation value of surrounding rock under different support parameters is obtained by simulation,the influence of support parameters on surrounding rock deformation is qualitatively analyzed,the safety of simulated excavation is determined by monitoring measurement datum value,and a reasonable joint support scheme is obtained.It is concluded that the deformation of surrounding rock is affected by shotcrete thickness,steel arch spacing and excavation step.The supporting methods of 0.28 m thick shotcrete,1m-spacing steel arch and 1m-spacing excavation can guarantee the safety of the tunnel excavation in this case.By comparing the simulation data with the field monitoring data,it is found that the variation value curves of the surrounding rock are basically identical,and the rationality of the numerical simulation is verified.Therefore,in future projects,the combination of the two can be used as a reference for the dynamic information of surrounding rock to guide the safety of the project.According to the analysis data,the surrounding rock deformation after tunnel excavation goes through four stages: slow deformation,rapid deformation,slow deformation and stable deformation,and the deformation value of the first two stages accounts for about 80% of the total deformation value.The dome at the entrance of the tunnel has a larger subsidence accumulative value and a faster deformation speed.With the increase of the tunnel burial depth and the decrease of the influence of bias,the dome's subsidence accumulative value decreases and the deformation velocity decreases,while the surrounding rock of the unbiased section is relatively stable.According to the research results,the deformation law of the surrounding rock,the most unstable position and the time of the violent deformation of the surrounding rock are obtained.Figure [38] table [9] reference [51]...