Optimization Analysis Of Tunnel Supporting Parameters In The Water-Rich Mudstone Section

The mudstone will engender softening expansion and rheological deformation, in case of water, which has been plagued by the problem of tunnel construction. This paper relies on water-rich mudstone section of ShuangFeng tunnel in Mu Sui railway, carrying on analysis about optimization of supporting parameters in rich mudstone section of ShuangFeng tunnel by the way of combining theoretical analysis, monitoring measurement and numerical simulation together. The main contents of this paper are as follows:(1)Taking a comprehensive analysis about the design theory of tunnel lining structure and the theory of supporting parameters optimization on the basis of consulting a large number of relevant literatures home and abroad. Selecting the reasonable support theory and the research methods of surrounding rock stability after taking a comprehensive comparison to guide the design of support parameters of the tunnel.(2)Analyzing the engineering properties of mudstone in the way of theoretical analysis, summarizing the form of tunnel failure and the factors affecting the stability of tunnel, and analyzing the features of advanced support, feet lock bolt, steel arch, Shotcrete support and the two concrete lining of the tunnel support system.(3)Taking the research of surrounding rock deformation, surrounding rock pressure,contact pressure and the change law of support force, after the excavation of the wat er- rich mudstone section by the analysis of monitoring measurement of ShuangFeng t unnel(DK465+362), and it will provide a reference for the design and construction of tunnel under the similar formation conditions.(4)Taking a analysis of plastic zone of surrounding rock of tunnel, displacement field and force of lining structure by using MIDAS-GTS finite element analysis software, combined with construction method and support design parameters of the water- rich mudstone section of ShuangFeng tunnel, in order to take the optimization of supporting parameters which includes length of anchor bolt, angle of anchor bolt, anchor bolt diameter, steel arch model, sprayed concrete thickness and two concrete lining thickness. The analysis results show that the support parameters used in the tunnel of the water-rich mudstone section are the feet lock bolt with length of 7m, oblique angle is 22.5 degrees, the diameter of 89 mm, the steel arch model I22 a, the sprayed concrete with thickness 35 cm, and the two concrete lining with thickness of 50 cm.