scholarly journals Fracture Behavior of Rock with Initial Damage: Theoretical, Experimental, and Numerical Investigations

Geofluids ◽  
2020 ◽  
Vol 2020 ◽  
pp. 1-9
Author(s):  
Hui Zhang ◽  
Panpan Guo ◽  
Yixian Wang ◽  
Yanlin Zhao ◽  
Hang Lin ◽  
...  
Keyword(s):  
Rock Mass ◽  
Fracture Behavior ◽  
Research Work ◽  
Jointed Rock ◽  
Jointed Rock Mass ◽  
Future Research ◽  
Fracture Characteristics ◽  
Failure Characteristics ◽  
Initial Damage

Geomaterials such as rock mass often have initial damage under the influence of long-term geological action and hydration corrosion environment. The initial damage affects the integrity and stability of the rock mass, resulting in a difference in the mechanical properties of jointed rock mass and intact one. Therefore, the study of the fracture and failure characteristics of the jointed rock mass is of great significance. Most of the previous researches into the fracture behavior of rock with initial damage are based on model testing, theoretical analysis, and numerical simulation of rock mass with preexisting flaws. This review concentrates on the theoretical, experimental, and numerical efforts that have been devoted to the fracture characteristics of rock or rock-like specimens with preexisting flaws under compression. Some suggestions on the future research work in this field are also given.

Blast Induced Damage Due to Repeated Vibrations in Jointed Gneiss Rock Formation

2010 ◽  
Vol 1 (1) ◽  
pp. 110-134 ◽  
Author(s):  
M. Ramulu ◽  
T. G. Sitharam
Keyword(s):  
Rock Mass ◽  
Dynamic Loading ◽  
Seismic Waves ◽  
Damage Zone ◽  
Research Work ◽  
Jointed Rock ◽  
Jointed Rock Mass ◽  
Rock Blasting ◽  
Hydroelectric Power ◽  
Blast Vibrations

Blasting is the most common method of rock excavation technique in mining and civil construction and infrastructure projects. Rock blasting produces seismic waves similar to those produced by earthquakes, but with relatively high frequency and low amplitude. General blast induced damage was extensively studied by researchers globally, but the studies on damage due to repeated blast vibrations is not yet reported, quantitatively, on underground openings. This paper deals with the research work carried on the effect of repeated dynamic loading imparted on the jointed rock mass from subsequent blasts in the vicinity, on the jointed rock mass at Lohari Nag Pala Hydroelectric Power Construction Project. The blast induced damage was monitored by borehole extensometers, borehole camera inspection surveys and triaxial geophones installed at three test sites of different joint orientations at the Main Access Tunnel of power house. The study reveals that there was extra damage of 60%, exclusively due to repeated blast vibrations. The results of the study indicate that repeated dynamic loading, resulted in damage even at 33% of the conventional damage threshold vibrations (Vc) in case of favorable joint orientations and 23% of Vc in case of unfavorable joints. The paper concludes in quantification of effect of repeated blast loading and the orientation of joints on the extension of damage zone in jointed rock mass of underground excavations.

scholarly journals Crack Initiation, Propagation, and Failure Characteristics of Jointed Rock or Rock-Like Specimens: A Review

2019 ◽  
Vol 2019 ◽  
pp. 1-31 ◽  
Author(s):  
Ri-hong Cao ◽  
Ping Cao ◽  
Hang Lin ◽  
Xiang Fan ◽  
Chunyang Zhang ◽  
...  
Keyword(s):  
Rock Mass ◽  
Crack Initiation ◽  
Failure Modes ◽  
Failure Process ◽  
Jointed Rock ◽  
Jointed Rock Mass ◽  
Failure Behavior ◽  
Failure Characteristics ◽  
Deformation And Failure ◽  
Natural Rock

Rock masses are heterogeneous materials containing a large number of discontinuities, and the failure of the natural rock mass is induced by the crack propagation and coalescence of discontinuities, especially for the rock mass around tunnel or underground space. Because the deformation or failure process of jointed rock mass exhibits strongly nonlinear characteristics, it is also very difficult to predict the strength and failure modes of the rock mass. Therefore, it is very necessary to study the failure mechanisms of jointed rock mass under different stress conditions. Apart from the stress condition, the discontinuities geometry also has a significant influence on the mechanical behavior of jointed rock mass. Then, substantial, experimental, and numerical efforts have been devoted to the study of crack initiation, propagation, and coalescence of rock or rock-like specimens containing different kinds of joints or fissures. The purpose of this review is to discuss the development and the contribution of the experiment test and numerical simulation in failure behavior of jointed rock or rock-like specimens. Overall, this review can be classified into three parts. It begins by briefly explaining the significance of studying these topics. Afterwards, the experimental and numerical studies on the strength, deformation, and failure characteristics of jointed rock or rock-like materials are carried out and discussed.

Blast Induced Damage Due to Repeated Vibrations in Jointed Gneiss Rock Formation

2012 ◽  
pp. 135-159
Author(s):  
M. Ramulu ◽  
T. G. Sitharam
Keyword(s):  
Rock Mass ◽  
Dynamic Loading ◽  
Seismic Waves ◽  
Damage Zone ◽  
Research Work ◽  
Jointed Rock ◽  
Jointed Rock Mass ◽  
Rock Blasting ◽  
Hydroelectric Power ◽  
Blast Vibrations

Blasting is the most common method of rock excavation technique in mining and civil construction and infrastructure projects. Rock blasting produces seismic waves similar to those produced by earthquakes, but with relatively high frequency and low amplitude. General blast induced damage was extensively studied by researchers globally, but the studies on damage due to repeated blast vibrations is not yet reported, quantitatively, on underground openings. This paper deals with the research work carried on the effect of repeated dynamic loading imparted on the jointed rock mass from subsequent blasts in the vicinity, on the jointed rock mass at Lohari Nag Pala Hydroelectric Power Construction Project. The blast induced damage was monitored by borehole extensometers, borehole camera inspection surveys and triaxial geophones installed at three test sites of different joint orientations at the Main Access Tunnel of power house. The study reveals that there was extra damage of 60%, exclusively due to repeated blast vibrations. The results of the study indicate that repeated dynamic loading, resulted in damage even at 33% of the conventional damage threshold vibrations (Vc) in case of favorable joint orientations and 23% of Vc in case of unfavorable joints. The paper concludes in quantification of effect of repeated blast loading and the orientation of joints on the extension of damage zone in jointed rock mass of underground excavations.

Effect of Repeated Blast Vibrations on Rock Mass Damage in Tunnels

2018 ◽  
pp. 215-244
Author(s):  
Ramulu More ◽  
T. G. Sitharam
Keyword(s):  
Rock Mass ◽  
Dynamic Loading ◽  
Research Work ◽  
Jointed Rock ◽  
Jointed Rock Mass ◽  
Common Method ◽  
Hydroelectric Power ◽  
Power Construction ◽  
Borehole Camera ◽  
Blast Vibrations

Blasting is the most common method of rock excavation technique in mining and civil construction and infrastructure projects. General blast-induced damage was extensively studied globally, but the studies on repeated blast induced damage is not yet reported, quantitatively. This chapter deals with the research work carried on the effect of repeated dynamic loading imparted on the jointed rock mass from subsequent blasts in the vicinity, on the jointed rock mass at Lohari Nag Pala Hydroelectric Power Construction Project. The blast-induced damage was monitored by borehole extensometers, borehole camera inspection surveys and triaxial geophones installed at three test sites of different joint orientations at the Main Access Tunnel of power house. The study reveals that the repeated blast vibrations resulted in extra damage of 60%. The results of the study indicate that repeated vibrations, resulted in inducing damage even at 23-33% of the critical vibrations (Vc) levels.

Failure Characteristics and Support Optimal Design of Columnar Jointed Rock Mass at a Diversion Tunnel

2013 ◽  
Vol 353-356 ◽  
pp. 1680-1684
Author(s):  
Xiang Dong Zhu ◽  
Lian Xing Hu ◽  
Jiang Quan ◽  
Shao Jun Li ◽  
Jun Li
Keyword(s):  
Rock Mass ◽  
Optimal Design ◽  
Jointed Rock ◽  
Jointed Rock Mass ◽  
Basaltic Lava ◽  
Diversion Tunnel ◽  
Failure Characteristics ◽  
Support Measures ◽  
Columnar Jointed Rock Mass ◽  
Columnar Joints

Columnar joints are native rupture structures which are ordered columnar forms in basaltic lava. The cracks and joints inside them are well-developed which lead to the weak self-supporting ability after excavation. At present, loose and collapse of columnar rock mass are the main problem in the hydraulic diversion tunnel. Based on field observation and test, this paper studied the failure characteristics of columnar joints in the diversion tunnel and simulated the failure mechanism. Based on this discussion, optimized support measures have been taken to ensure the safe construction of the diversion tunnel.

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