Damage evolution mechanisms of rock in deep tunnels induced by cut blasting

Abstract The method of cut blasting is widely used in tunnelling excavation, which concerns the success in subsequent stop blasting and smooth blasting. Rock masses in deep tunnels are subjected to high in-situ stress, and the mechanisms of damage evolution of rock mass in deep tunnels induced by cut blasting are not well studied. In this paper, a tension and compression-shear damage model is developed, and then is implemented into the commercial software LS-DYNA as a user-defined material model. To validate the newly developed model, the comparison between numerical results and an existing field test is conducted. The effects of free-surface boundary conditions, in-situ stress and the coefficient of lateral pressure on cut blasting are considered in depth. Numerical results indicate that the superstition of stress wave and the reflected tension waves from free surfaces contribute to the damage interconnection near cut holes. The high in-situ stress has the resistance on the radially oriented pressure and the damage extension around cut holes. The coefficients of lateral pressure influence the extending direction of the tensile damage zone.

[1]  R. N. Gupta,et al.  On the application of rock mass quality for blasting in large underground chambers , 1999 .

[2]  Ming Cai,et al.  Principles of rock support in burst-prone ground , 2013 .

[3]  Yong Lu,et al.  Numerical prediction of blast‐induced stress wave from large‐scale underground explosion , 2004 .

[4]  Peter K. Kaiser,et al.  Rock mass response ahead of an advancing face in faulted shale , 2013 .

[5]  Guowei Ma,et al.  Numerical simulation of blasting-induced rock fractures , 2008 .

[6]  Anastasio P. Santos,et al.  Determination of the JWL Constants for ANFO and Emulsion Explosives from Cylinder Test Data , 2015 .

[7]  Wancheng Zhu,et al.  2D numerical simulation on excavation damaged zone induced by dynamic stress redistribution , 2014 .

[8]  M. A. Kayupov,et al.  Studies of the effect of dynamic processes during explosive break-out upon the roof of mining excavations , 1988 .

[9]  Jian Zhao,et al.  A Review of Dynamic Experimental Techniques and Mechanical Behaviour of Rock Materials , 2014, Rock Mechanics and Rock Engineering.

[10]  Heping Xie,et al.  Numerical investigation of blasting-induced damage in cylindrical rocks , 2008 .

[11]  Yan Peng,et al.  RESEARCH ON TRANSIENT CHARACTERISTICS OF EXCAVATION UNLOADING , 2008 .

[12]  M. Y. Koca,et al.  Impact of the mechanical characteristics of weak rocks and trona ore beds on the main drift deformation at the beypazari mine, Turkey , 2004 .

[13]  G. Bäckblom,et al.  Recent experiments in hard rocks to study the excavation response: Implications for the performance of a nuclear waste geological repository , 1999 .

[14]  Xin Wang,et al.  Influence of wavelength-to-excavation span ratio on ground motion around deep underground excavations , 2015 .

[15]  Peng Yan,et al.  Dynamic response of rock mass induced by the transient release of in-situ stress , 2012 .

[16]  Dusan Krajcinovic,et al.  Statistical aspects of the continuous damage theory , 1982 .

[17]  S. Kwon,et al.  An investigation of the excavation damaged zone at the KAERI underground research tunnel , 2009 .

[18]  Tugrul Unlu,et al.  Three dimensional numerical rock damage analysis under blasting load , 2013 .

[19]  Ming Cai,et al.  Generalized crack initiation and crack damage stress thresholds of brittle rock masses near underground excavations , 2004 .

[20]  Yvonne D Murray,et al.  Manual for LS-DYNA Wood Material Model 143 , 2007 .

[21]  L. M. Taylor,et al.  Microcrack-induced damage accumulation in brittle rock under dynamic loading , 1986 .

[22]  M. R. Saharan,et al.  Numerical Procedure for Dynamic Simulation of Discrete Fractures Due to Blasting , 2008 .

[23]  Jianhua Yang,et al.  Numerical Simulation of Rock Mass Damage Evolution During Deep-Buried Tunnel Excavation by Drill and Blast , 2015, Rock Mechanics and Rock Engineering.

[24]  N Jones,et al.  STRUCTURAL ASPECTS OF SHIP COLLISIONS , 1983 .

[25]  Peng Yan,et al.  Transient characters of energy changes induced by blasting excavation of deep-buried tunnels , 2015 .

[26]  Ming Cai,et al.  Influence of stress path on tunnel excavation response – Numerical tool selection and modeling strategy , 2008 .

[27]  Zhou Chuangbing.  COMPARISON OF DAMAGE EVOLUTION PROCESS OF HIGH ROCK SLOPE EXCAVATED BY DIFFERENT METHODS , 2013 .

[28]  W. F. Bawden,et al.  A new constitutive model for blast damage , 1996 .

[29]  B. Mohanty,et al.  Numerical simulation of stress wave induced fractures in rock , 2012 .

[30]  M. E. Kipp,et al.  Continuum modelling of explosive fracture in oil shale , 1980 .

[31]  Li Haibo,et al.  Rock damage control in bedrock blasting excavation for a nuclear power plant , 2011 .

[32]  John P. Carter,et al.  SUDDEN EXCAVATION OF A LONG CIRCULAR TUNNEL IN ELASTIC GROUND , 1990 .