Influence of concealed karst cave on surrounding rock stability and its treatment technology
- CHEN Yucheng, WANG Zhaoyang, GUO Ming, LIN Peng
Journal of Shandong University(Engineering Science). 2020, 50(5):
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On the basis of the investigation and statistical analysis of karst caves of tunnel project in E-Xi mountains area, they were classified according to the karst cave volume, shape, cavity filling material and water gushing channel type. The result presented that the karst cavities in the mountains area of E-Xi were of different sizes, various shapes, various cavity filling materials and complicated water gushing channel. The changes of stress field and displacement field of tunnel surrounding rock under the influence of different location of hidden karst cave were studied through numerical simulation analysis, which showed that the high stress area and low stress area of surrounding rock were different with different location of hidden karst cave. With the changes of location of karst cave, the maximum settlement value from large to small were spandrel extension line, sidewall, spandrel extension line, top of arch, bottom of slab. With the descend of the location of the karst cave, the distribution rule of the maximum horizontal convergence from large to small were spandrel extension line, above the arch crown, sidewall, below the bottom plate, spandrel extension line. With the descend of the location of the karst cave, the deformation law of surrounding rock the settlement of tunnel from large to small were vault, haunch, arch foot, base plate. Based on the characteristics of karst type, the results of numerical simulation of stress field and displacement change of surrounding rock, the prevention and control principles of karst cave were sorted out. Huaguoshan tunnel was taken as an example to explain in detail and the treatment scheme was put forward.