Tunnel Mechanical Behavior Of Soft Slate And Control Technology

The soft-rock large deformation is a technological difficulty that needed to be solved during the construction of tunnels. Based on the project of the Transport Department of Hunan province, and supported by the HuaiTong Expressway tunne, this dissertation launched the research on the mechanical behaviour of the soft-rock large deformation and the monitoring technique. The main work in this paper is concluded as follows:1. The components and microstructure of the selected slate samples were analyzed by an electron microscope to understand its composition, structure and feature of the cement way. Through the characteristic of water absorption, swelling, disintegration of the slate to understand the impact of the water on the slate and variation and find the formula of the changing law with the water absorption and the water swelling, furthermore obtained the corresponding parameters; through the compression tests which is under the conditions of different angle and different moisture content to understand the slate anisotropy and the effect of the water in the slate Mechanical Properties; Based on the Existence condition of water in the slate,contact angle and micro-structure, this paper analyses and illustrates the water-weakening properties mechanism of slates.2. Based on collating and analyzing existing creep theory and constitutive model, this paper proposed a constitutive law for this study according to he nature of the slate; described and analyzed the typical creep process detailedly according to the creep theory; based on the indoor compression test, we analyze the law of the different pressure difference and the different moisture content affect creep characteristics of slate, and then fitted experimental results based on proposed constitutive model; finally, we conducted a simple analysis of how water can analyze creep rules and mechanisms from the micro.3.By using the FLAC3D, this paper conducted a numerical simulation of the Excavation Support of weak slate tunnel and deformation control, established 3 kinds of excavation and support models:shotcrete-bolt support,increased grouting and advance timbering, and proceeded numerical calculation. From the aspect of the stress of situation, the vault settlement and the Horizontal displacement of tunnels a comparation of the three model was taken. A discussion about the result of deformation control of the weak slate of tunnel support systems was taken, So as to conclude the most safe and economic solution of the soft rock tunnel support and the large deformation control.4.The actual monitoring data of the soft slate Zhengtuanchong tunnel was Collated and analyzed, and a comparation of the actual monitoring results, fitting results and the numerical results was made. By analyzing the reasonableness of the monitoring regression and the monitoring results, the security status of the tunnel construction was evaluated.