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Deformation Prediction and Parameter Sensitivity Analysis of Pipe Roof in Shallow Soft Rock Tunnels Considering
(1 Department of Civil Engineering, Hebei Jiaotong Vocational and Technical College，Shijiazhuang 050091; 2 Key Laboratory of Transportation Tunnel Engineering of Ministry of Education, Southwest Jiaotong University, Chengdu 610031; 3 School of Civil Engineering,Shijiazhuang Tiedao University, Shijiazhuang 050043; 4 CSCEC Road and Bridge Group Co., Ltd, Shijiazhuang 050001)
Abstract In view of the complexities of existing calculation methods and theories for tunnel pipe roof, effects of calculation parameters on analysis results and difficulties to obtain accurate theoretical solution or simplified calculation formula, a theoretical calculation model for predicting deformation of pipe roof as pre-support was established based on Winkler elastic foundation beam theory and considering the disturbance characteristics of surrounding rock, incomplete load bearing behavior due to unclosed support, differences of strata reaction coefficients and uneven load distribution, and a theoretical solution was obtained by solving 24 order equations. The results show that:(1) The analytical solution agrees well with numerical simulation value and field data, and it can be used to predict deformation of pipe roof; (2) it is available to have the optimal parameters of diameter, advance rate and strata reaction coefficient of pipe roof, the circumferential spacing is directly proportional to pipe roof deformation, it meets the requirement only if the length of pipe roof at the far end is not less than two times of the bench height in front of working face; (3)The sequences of controlling effect of vault settlement by adjusting pipe parameters are advance rate, strata mechanical behavior improvement by grouting, circumferential spacing, diameter and length in the order from good to bad.
Abstract：
In view of the complexities of existing calculation methods and theories for tunnel pipe roof, effects of calculation parameters on analysis results and difficulties to obtain accurate theoretical solution or simplified calculation formula, a theoretical calculation model for predicting deformation of pipe roof as pre-support was established based on Winkler elastic foundation beam theory and considering the disturbance characteristics of surrounding rock, incomplete load bearing behavior due to unclosed support, differences of strata reaction coefficients and uneven load distribution, and a theoretical solution was obtained by solving 24 order equations. The results show that:(1) The analytical solution agrees well with numerical simulation value and field data, and it can be used to predict deformation of pipe roof; (2) it is available to have the optimal parameters of diameter, advance rate and strata reaction coefficient of pipe roof, the circumferential spacing is directly proportional to pipe roof deformation, it meets the requirement only if the length of pipe roof at the far end is not less than two times of the bench height in front of working face; (3)The sequences of controlling effect of vault settlement by adjusting pipe parameters are advance rate, strata mechanical behavior improvement by grouting, circumferential spacing, diameter and length in the order from good to bad.
.Deformation Prediction and Parameter Sensitivity Analysis of Pipe Roof in Shallow Soft Rock Tunnels Considering[J] MODERN TUNNELLING TECHNOLOGY, 2019,V56(1): 79-86
2019, Vol. 56 