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PFC3D-Based Analysis of the Time-Dependent Characteristics of Rock Deformation and Fracturing around a Deeply-Buried Round Tunnel
(1 School of Civil Engineering, Henan Polytechnic University, Jiaozuo 454000; 2 State Key Laboratory for Geomechanics & Deep Underground Engineering, China University of Mining and Technology, Xuzhou 221116)
Abstract The time-dependent characteristics of rock deformation and fracturing are key issues concerning the sta? bility and control of deep tunnels. Based on a deeply-buried tunnel, the discrete particle flow code software PFC3D and a physical model test were used to analyze the spatio-temporal evolution law and mechanism of rock deformation and fracturing around the deep roadway. The research results show that: 1) the deformation of the roadway surrounding rock has a "step" growth relationship with the excavation time and has an exponential decay relationship with the distance from the roadway surface; 2) moving forward, shear slip cracks occur at two sides of the roadway near the haunch and gradually expand toward the roof and floor, with the number of cracks and rupture fractal dimension increasing in an exponential decay; and 3) the shear stress transfer of the tunnel rock mass is a process of lagging and attenuation, the shear stress of the shallow-buried rock mass at two sides of the tunnel increases rapidly and results in a yield fracture, and the shear stress of the rock mass at that place transfers more deeply and leads to ductile shear failure of the nearby rock, and obvious shear slip cracks occur.
Abstract：
The time-dependent characteristics of rock deformation and fracturing are key issues concerning the sta? bility and control of deep tunnels. Based on a deeply-buried tunnel, the discrete particle flow code software PFC3D and a physical model test were used to analyze the spatio-temporal evolution law and mechanism of rock deformation and fracturing around the deep roadway. The research results show that: 1) the deformation of the roadway surrounding rock has a "step" growth relationship with the excavation time and has an exponential decay relationship with the distance from the roadway surface; 2) moving forward, shear slip cracks occur at two sides of the roadway near the haunch and gradually expand toward the roof and floor, with the number of cracks and rupture fractal dimension increasing in an exponential decay; and 3) the shear stress transfer of the tunnel rock mass is a process of lagging and attenuation, the shear stress of the shallow-buried rock mass at two sides of the tunnel increases rapidly and results in a yield fracture, and the shear stress of the rock mass at that place transfers more deeply and leads to ductile shear failure of the nearby rock, and obvious shear slip cracks occur.
.PFC3D-Based Analysis of the Time-Dependent Characteristics of Rock Deformation and Fracturing around a Deeply-Buried Round Tunnel[J] MODERN TUNNELLING TECHNOLOGY, 2017,V54(2): 73-80
2017, Vol. 54 