Zonal disintegration mechanism ofisotropic rock masses around a deep spherical tunnel
来源期刊：中南大学学报(英文版)2015年第10期
论文作者：GU Xin-bao BI Jing XU Ming
文章页码：4074 - 4082
Key words：zonal disintegration mechanism; isotropic rock mass; spherical tunnel; dynamic unloading
Abstract: In order to investigate zonal disintegration mechanism of isotropic rock masses around a deep spherical tunnel, a new mechanical model subjected to dynamic unloading under hydrostatic pressure condition is proposed. The total elastic stress-field distributions is determined using the elastodynamic equation. The effects of unloading rate and dynamic mechanical parameters of isotropic deep rock masses on the zonal disintegration phenomenon of the surrounding rock masses around a deep spherical tunnel as well as the total elastic stress field distributions are considered. The number and size of fractured and non-fractured zones are determined by using the Hoek-Brown criterion. Numerical computation is carried out. It is found from numerical results that the number of fractured zones increases with increasing the disturbance coefficient, in-situ stress, unloading time and unloading rate, and it decreases with increasing parameter geological strength index, the strength parameter and the uniaxial compressive strength of intact rock.
GU Xin-bao(谷新保)1, 2, BI Jing(毕靖)1, XU Ming(许明)1
(1. School of Civil Engineering, Chongqing University, Chongqing 400045, China;
2. Institute of architecture and engineering, Sichuan University of science and Engineering, Zigong 643000, China)
Abstract:In order to investigate zonal disintegration mechanism of isotropic rock masses around a deep spherical tunnel, a new mechanical model subjected to dynamic unloading under hydrostatic pressure condition is proposed. The total elastic stress-field distributions is determined using the elastodynamic equation. The effects of unloading rate and dynamic mechanical parameters of isotropic deep rock masses on the zonal disintegration phenomenon of the surrounding rock masses around a deep spherical tunnel as well as the total elastic stress field distributions are considered. The number and size of fractured and non-fractured zones are determined by using the Hoek-Brown criterion. Numerical computation is carried out. It is found from numerical results that the number of fractured zones increases with increasing the disturbance coefficient, in-situ stress, unloading time and unloading rate, and it decreases with increasing parameter geological strength index, the strength parameter and the uniaxial compressive strength of intact rock.
Key words:zonal disintegration mechanism; isotropic rock mass; spherical tunnel; dynamic unloading
