Study Of Characteristics Of Grouting Material And Its Application In Deformation Calculation Of Tunnel Construction

This article summarizes present status and open questions on ground deformation due to shield excavation. When the shield constructing, grouting material injected in the tail voids is solidifying gradually and its mechanical characteristics is changing continuously. This variation effects the regularities of distribution on ground movement. So the thesis concentrates on the study of the regularities of ground deformation as grouting material solidifies in tunneling construction. The main studies of the paper are as follows:1. The load form of the grouting in shield excavation, which is load or unload is very important to its deformation. The article obtains the regularities of distribution though analyzing the whole process of shield excavation, and the Mindlin solution and empirical fit method are used to simulate the variable trend of ground stress.2. Considering time effect of solidification, rheology law is applied to simulate the coagulation of the grouting material. According to actual stress regularity of grouting, rheological tests under constant load and variable load are designed and performed. Unload nonlinear rheological model is gained by effective theory analysis.3. The analytical solution of non-axisymmetrical cavity contraction in semi-finite is applied to simulate the surface subsidence owing to the coagulation of the grouting material. The law of ground movement is analyzed for the nanjing subway of zhangfuyuan-xinjiekou shield tunneling part. Through the comparing calculation, the regularities of the surface subsidence are obtained due to change of the grouting thickness, soil property and depth of tunnel embedment.