Research on Formation Process of Zonal Disintegration in Deep Rock Mass Based on Field Monitoring and Geomechanical Model Test

2018 ◽  
Vol 36 (4) ◽  
pp. 2725-2733 ◽  
Author(s):  
Zhang Xutao ◽  
Xue Junhua ◽  
Duan Changrui
Keyword(s):  
Rock Mass ◽  
Model Test ◽  
Formation Process ◽  
Field Monitoring ◽  
Zonal Disintegration ◽  
Geomechanical Model ◽  
Geomechanical Model Test ◽  
Deep Rock Mass ◽  
Deep Rock

Numerical Study on Zonal Disintegration of Deep Rock Mass Using Three-Dimensional Bonded Block Model

2019 ◽  
Vol 2019 ◽  
pp. 1-12 ◽  
Author(s):  
Qingteng Tang ◽  
Wenbing Xie ◽  
Xingkai Wang ◽  
Zhili Su ◽  
Jinhai Xu
Keyword(s):  
Rock Mass ◽  
Fracture Zone ◽  
Numerical Study ◽  
Confining Pressure ◽  
Surrounding Rock ◽  
Zonal Disintegration ◽  
Block Model ◽  
Deep Rock Mass ◽  
Damaged Zone ◽  
Deep Rock

Zonal disintegration, a phenomenon of fractured zones and intact zones distributed alternately in deep rock mass, is different from the excavation-damaged zone of shallow rock mass. In this study, bonded block model of 3DEC was employed to study the fracture mode and origination condition of zonal disintegration. Initiation, propagation, and coalescence progress of fracture around the roadway boundary under different triaxial stress conditions are elaborated. Numerical simulation demonstrated that zonal disintegration may occur when the direction of maximum principal stress is parallel to the roadway axis. It is interesting to find that the fracture around the roadway boundary traced the line of a spiral line, while slip-line fractures distributed apart from the roadway boundary. The extent of the alternate fracture zone decreased as the confining pressure increased, and alternate fracture zone was no longer in existence when the confining pressure reaches a certain value. Effects of roadway shape on zonal disintegration were also studied, and the results indicated that the curvature of the fracture track line tends to be equal to the roadway boundary in shallow surrounding rock of the roadway, while the fractures in deep surrounding rock seems unaffected by the roadway shape. Those findings are of great significance to support design of deep underground openings.

scholarly journals Research on Failure Mechanism and Parameter Sensitivity of Zonal Disintegration in Deep Tunnel

2019 ◽  
Vol 2019 ◽  
pp. 1-10 ◽  
Author(s):  
Xutao Zhang ◽  
Qiang Gao ◽  
Shicai Cui ◽  
Changrui Duan
Keyword(s):  
Rock Mass ◽  
Failure Mechanism ◽  
Deformation Modulus ◽  
Morphological Characteristics ◽  
Zonal Disintegration ◽  
Deep Tunnel ◽  
Equilibrium Equations ◽  
Distribution Law ◽  
Deep Rock Mass ◽  
Deep Rock

With the increase of excavation depth, the zonal disintegration phenomenon appears in the deep rock mass, which is quite different from the failure mode of shallow tunnel. In order to analyse the failure mechanism of this phenomenon, an elastoplastic softening damage model was put forward based on the softening damage characteristics of deep rock mass. The constitutive equations, the equilibrium equations, and the failure criterion were deduced. The theoretical solutions of radial displacement and radial stresses and tangential stresses of deep surrounding rock mass were calculated. The distribution law of zonal disintegration in deep tunnel was obtained. The theoretical solutions presented an oscillating mode. The theoretical calculated widths of fracture zones were in good agreement with the in situ test data. Besides, the sensitivity of different parameters to fracture morphology was calculated and analysed. The results show that the relative loading strength has a controlling role in the zonal disintegration morphology, followed by the cohesion force and deformation modulus, and the internal friction angle is the least. This study reveals the morphological characteristics and influencing factors of zonal disintegration, which provides a basis for the prediction and support control of fracture modes.

scholarly journals Experimental Study on the Ratio of Similar Materials in Weak Surrounding Rock Based on Orthogonal Design

2018 ◽  
Vol 2018 ◽  
pp. 1-6 ◽  
Author(s):  
Pengfei Jiao ◽  
Xiao Zhang ◽  
Xinzhi Li ◽  
Bohong Liu ◽  
Haojie Zhang
Keyword(s):  
Model Test ◽  
Orthogonal Design ◽  
Surrounding Rock ◽  
Similar Material ◽  
Geomechanical Model ◽  
Geomechanical Model Test ◽  
Geological Conditions ◽  
Key Factor ◽  
Similar Materials ◽  
Weak Surrounding Rock

In the aspect of stability analysis of tunneling engineering, geomechanical model test is an important research method. A similar material is the prerequisite for the success of geomechanical model test. In the field of major engineering applications, a variety of similar materials are prepared for different geological conditions of surrounding rock and applied in some major engineering. With the use of standard sand, fine sand, and silt clay as materials, similar materials for weak surrounding rock were developed. Based on the orthogonal design method, through the direct shear test, the range analysis and variance analysis of various factors affecting the physical and mechanical parameters of weak surrounding rock are carried out. The results show similar material can meet the requirements in weak surrounding rock. Standard sand is the key factor that influences the internal friction angle of similar materials, and silt clay is the key factor affecting the cohesion of similar materials. Similar materials can meet the elastic modulus and severe requirements of the weak surrounding rock and can be used for the weak surrounding rock engineering. The new type of similar material configuration is widely used in shallow buried tunnel entrance section and urban shallow buried excavation engineering, in addition to tunnel engineering in loess stratum, and the problems of engineering design and construction are solved through geomechanical model test.

Sign in / Sign up

Export Citation Format

Share Document