Abstract It is important to accurately predict rock bursts in unexcavated tunnel sections for the safe and rapid construction of tunnels. Aiming at the characteristics of tunnel rock bursts, a unified solution to the stress of the circular section under the effects of lateral pressure is obtained by a complex variable function solution proposed by Muskhelishvili and based on conformal mapping function represented by the Laurent series of infinite single connected domain. With proper criteria for rock bursts, a comprehensive assessed grade of rock bursts is determined, and a comparison of the calculation results, numerical simulation results and actual results of rock bursts is conducted.The results show that: 1) stress concentrations with different degrees occur at different parts of the surrounding rock,and the maximum compressive stress mainly occurs at the crown after excavation; 2) stress concentration and abrupt change could occur at the structural surface after excavation of a deep-buried tunnel section due to the effects of tectonic stress; and 3) the analytic calculation results and numerical simulation results agree well with the actual results of rock bursts, which demonstrates the effectiveness of this analysis method with complex variable function.
Abstract：
It is important to accurately predict rock bursts in unexcavated tunnel sections for the safe and rapid construction of tunnels. Aiming at the characteristics of tunnel rock bursts, a unified solution to the stress of the circular section under the effects of lateral pressure is obtained by a complex variable function solution proposed by Muskhelishvili and based on conformal mapping function represented by the Laurent series of infinite single connected domain. With proper criteria for rock bursts, a comprehensive assessed grade of rock bursts is determined, and a comparison of the calculation results, numerical simulation results and actual results of rock bursts is conducted.The results show that: 1) stress concentrations with different degrees occur at different parts of the surrounding rock,and the maximum compressive stress mainly occurs at the crown after excavation; 2) stress concentration and abrupt change could occur at the structural surface after excavation of a deep-buried tunnel section due to the effects of tectonic stress; and 3) the analytic calculation results and numerical simulation results agree well with the actual results of rock bursts, which demonstrates the effectiveness of this analysis method with complex variable function.
2018, Vol. 55 