| With the deepening of infrastructure, there will be more tunnels through highgeo-stress soft rock area in highway tunnel construction in China. Due to thecomplexity of the high geo-stress soft rock as well as a variety of geological conditions,and the soft rock tunnel mechanical effects are significant differences in different highgeo-stress zones, so study on the large deformation problems and the forcecharacteristics of supporting structure become very prominent in high geo-stress softrock tunnel. The paper is based on the project of a high-speed tunnel in Chongqing.Study the mechanical effects of the initial support in western high geo-stress softsurrounding rock tunnel through theoretical studies, field tests and numerical simulation,risk assessment for high geo-stress soft rock tunnel during the construction process, andput forward safety control measures and providing a reference for the design andconstruction of similar projects. The thesis work carried out and the results achieved areas follows:①The thesis expounds systematically the characteristics of high geo-stress zone,the formation conditions, mechanical properties and deformation mechanism of the highgeo-stress soft surrounding rock, and study the deformation and failure mechanism inhigh geo-stress soft rock tunnel on this basis;②Based on the project to develop the field test program, testing the stress of steelsupports, the contact pressure of surrounding rock and shotcrete strain, processing andanalysis of test data, and obtained the force characteristics of initial support in highgeo-stress soft surrounding tunnel③According to the site conditions of the tunnel, using FLAC3Dsoftware to create athree-dimensional numerical model, numerical simulating the excavation process basedon the project, and obtained the force and deformation characteristics of surroundingrock, initial support in high geostress soft rock tunnel during the construction process.Compared to the field test results, and providing reference for the rational design andconstruction of initial support.④According to numerical simulation, investigating the mechanical effect of theinitial supporting with different lateral pressure coefficients, different levels ofsurrounding rock and the different depths in geo-stress soft rock tunnel, and obtainedthe force and deformation characteristics of initial support with the different influencingfactors. ⑤Using “The highway bridge and tunnel engineering construction safety riskassessment guidelines” to risk assessment for high geostress soft rock tunnel during theconstruction process, and put forward safety control measures. |
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