Numerical Simulation Of Surrounding Rock Stability During Excavation Of A Tunnel

In this paper, based on the fried Zhashanzui tunnel in Gnyuan City, Ningxia Hui Autonomous Region, YK25+330?YK25+360 encountered a large deformation of the surrourding rock, and there was water seepage in the excavation process. In order to prevent similar problems in the follow-YK25+250?YK25+280 and YK25+350?YK25 + 360 sections were selected. The model established by ABAQUS model. The stability seepage of surrounding rock were calculated and analyzed ,and the surrounding rock The stress and strain changes and the distriibution of pore water pressure and discuss the impact of these laws on the subility of the tunnel.(1) The surrounding displacement of the tunnel is related not only to the initial stress field,the strength porameter c. the value of the surrounding rock itself and the size of the tunnel structure but also to the support structure (support resistance). When the support resistance increases, Displacement will be reduced, on the contrary, support resistance decrrases, the plastic displacement of the surrounding rock will increase, or even instability.(2) The YK25+250 section and the YK25+330 section are selected. The ABAQUS is used to calculate the two-dimensional model under rcasonable parameter condition. Under this gcological condition. the arching scttlement increases with the initial thickness, the concrete strength and the length of the bolt. Roeduce, but affect a certain value, and then increase the impact on the vault can be ignored .(3) A three-dimensional model was established on ABAQUS by using YK25+250-YK25+280 and YK25+280 and YK25+360. The stress and strain of surrounding rock and the change of pore water pressure during tunnel excavation were calculated. The maximum stress of YK25+250 - YK25+280 is affected by the stress at the two side walls, and the horizontal displacement of the two side walls ibcrcases and the pore water pressure decreases to the minimum. The maximum stress of YK25+330-YK25 +360 is at the vault. and the horizontal displacement of the vault increases with the increase of the stress. The change of the pore water pressure also directly affects the change of the stress(4) The asurface displacement of the tunnel. the settlement of the arch, the convergence of the surrounding rock and the statistical analysis of the monitoring data to find out the variation law of the tunnel surrounding rock during the tunnel excavation, and compare it with the data compiled by the numerical simulation , To determine the correctness and rationality of the simulation calculation, based on the results to guide the follow-up engineering design and construction.