| The rock and soil mass is in three phase conditions, consists of air, liquid and solid particles in nature state. The fluid and solid particles influence each other and determine the properties of rock and soil mass together. Fluid-solid coupling analysis can reflect the real situation well and make the result more reliable.Qingshui railway tunnel, located in Funing country of guangxi autonomous region, is in Luo-Zhan railroad Yongzhou to Chenxi section. The tunnel has the following characteristics: it’s a shallow tunnel and buried biasly, the surrounding rock crushed, riched in groundwater. When excavating the tunnel, the displacement of the tunnel-liner was large and collapsed many times. What was worse, it Induced mountain cracking. So it endangersd the safety of construction personnel and influenced the progress of the projects seriously.Based on Qingshui railway tunnel project, the seepage of altered rocks area in tunnel is studied deeply by methods of model test and numerical simulation. The tunnel deformation mechanism and curtain grouting technology applications in altered rock area are revealed, which can provide technical support in altered rock area tunnel excavation with full of water.The main work is as follows:(1) The geological condition, the large deformation, water gushing, collapse, mountain cracking and the corresponding measures in spot of the Qingshui railway was introduced systematically.(2) According to the monitoring data, the FLAC3D software was used to inversion to confirm the altered rock macro parameters, at the same time, boring water pressure field test was done to find the permeability coefficient in the area of the tunnel, which can provide parameters for the next steps of analysis.(3) In order to reveal seepage and soften of the altered rock how to effect the stability of the Qingshui railway tunnel, the PHASE software was used to make Fluid-solid coupling analysis and model test was done. The result was that the seepage and softens of the altered rock played a decisive role to the Qingshui railway tunnel stability. The advice was given that tunnel excavation in this area full of water shall give priority to stopping water, which can prevent form the seepage apparently.(4) Using ABAQUS finite element software simulate the application of the curtain grouting technology in seepage condition of Qingshui railway tunnel, and determine the optimal thickness of the Grouting circle and Sealing batholitic. Under the certain conditions of Qingshui railway tunnel, the optimal thickness of the Grouting circle is2.5m and sealing batholitic is4m. Promoted to the general situation, the optimal thickness of the grouting circle is0.25times of tunnel equivalent diameter and the sealing batholitic is0.4times of tunnel equivalent diameter, which can guide the tunnel excavation in altered rock area rich in water. |
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