| Huaping tunnel is an important section of the Lijiang-Panzhihua highway, the water sensitivity of Xigeda rock formation lead to engineering problems frequently. Therefore, it is significant to give the study of the characteristic of Xigeda rock formations. It will provide data theory and examples for the construction of Xigeda regional in Panxi and Yunnan, and it is also related to the safety and economy of the tunnel engineering. In this paper, LiPan highway will be used as the study example,and the classification and evaluation of the stability of tunnel rock will be acquired by the geological surveys and the analysis of large amounts of test data, And FLAC3D is used to simulate the stress and strain characteristics under different ways of tunnel excavation.The main contents of the study are as follows:(1)Under the field surveys and consulting with the regional geological data,we clarified the distribution and regional geology of Huaping tunnel in Xigeda stratigraphic. On this basis, we developed a large number of routine soil tests and microscopic geotechnical tests to study mechanical engineering characteristics under different soil types, stresses, moisture conditions and coupling conditions;What’s more,the hydrophilic of Xigeda stratigraphic has been analyzed, and the parameters of physical mechanical tests have been obtained.(2)According to the test datas,we extracted the affecting factors of stability of surrounding rock in Huaping Xigeda strata, and analyzed the range and right weight of each factor using mathematical statistics methods and AHP. Thereby established the criteria of the stability of surrounding rock Huaping in Xigeda formations,at the same time,we proposed methods of classification of tunnel rock.(3) Numerical simulation software has been used to analyze the stress-strain characteristics during the tunnel excavation, and the recommendations has been given combined with the actual construction conditions. |
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