scholarly journals Deformation and Failure Characteristics of the Rock Masses around Deep Underground Caverns

2015 ◽  
Vol 2015 ◽  
pp. 1-13 ◽  
Author(s):  
Chong Zhang ◽  
Zhechao Wang ◽  
Qi Wang
Keyword(s):  
Model Test ◽  
Similarity Theory ◽  
Stress Conditions ◽  
Rock Masses ◽  
Failure Characteristics ◽  
Deformation And Failure ◽  
Underground Caverns ◽  
Deep Rock ◽  
Deep Underground ◽  
Ground Stress

The deformation and failure characteristics of deep rock masses are the focus of this study on deep rock mass engineering. The study identifies the deformation and failure characteristics of a deep cavern under different ground stress conditions using model test and theoretical analysis methods. First, the similarity theory for model tests is introduced, and then the scale factors used in the present study are calculated according to the Froude criterion. Based on the study objectives, the details of the study methods (the similarity coefficient, the loading conditions, the test steps, etc.) are introduced. Finally, the failure characteristics of the deep cavern and the strain distribution characteristics surrounding the caverns under different ground stress conditions are identified using the model test. It was found that compared with shallow rock masses the rock masses of the deep cavern have a much greater tensile range, which reaches 1.5 times the diameter of the cavern under the conditions established in the present study. Under different ground stress conditions, there are differences in failure characteristics and the reasons of the differences were analyzed. The implication of the test results on the design of support system for deep caverns was presented.

scholarly journals Model Test of Anchoring Effect on Zonal Disintegration in Deep Surrounding Rock Masses

2013 ◽  
Vol 2013 ◽  
pp. 1-16 ◽  
Author(s):  
Xu-Guang Chen ◽  
Qiang-Yong Zhang ◽  
Yuan Wang ◽  
De-Jun Liu ◽  
Ning Zhang
Keyword(s):  
Model Test ◽  
Surrounding Rock ◽  
Zonal Disintegration ◽  
Formation Condition ◽  
Anchor Effect ◽  
Rock Masses ◽  
Tunnel Excavation ◽  
Anchoring Effect ◽  
Tension And Compression ◽  
Deep Rock

The deep rock masses show a different mechanical behavior compared with the shallow rock masses. They are classified into alternating fractured and intact zones during the excavation, which is known as zonal disintegration. Such phenomenon is a great disaster and will induce the different excavation and anchoring methodology. In this study, a 3D geomechanics model test was conducted to research the anchoring effect of zonal disintegration. The model was constructed with anchoring in a half and nonanchoring in the other half, to compare with each other. The optical extensometer and optical sensor were adopted to measure the displacement and strain changing law in the model test. The displacement laws of the deep surrounding rocks were obtained and found to be nonmonotonic versus the distance to the periphery. Zonal disintegration occurs in the area without anchoring and did not occur in the model under anchoring condition. By contrasting the phenomenon, the anchor effect of restraining zonal disintegration was revealed. And the formation condition of zonal disintegration was decided. In the procedure of tunnel excavation, the anchor strain was found to be alternation in tension and compression. It indicates that anchor will show the nonmonotonic law during suppressing the zonal disintegration.

scholarly journals Development and Application of an Intelligent Test System for the Model Test on Deep Underground Rock Caverns

Energies ◽  
2020 ◽  
Vol 13 (2) ◽  
pp. 358
Author(s):  
Chuancheng Liu ◽  
Qiangyong Zhang ◽  
Kang Duan ◽  
Wen Xiang ◽  
Yuyong Jiao
Keyword(s):  
Model Test ◽  
Nonlinear Deformation ◽  
Test System ◽  
Physical Model Test ◽  
Test Accuracy ◽  
Deformation Characteristics ◽  
Human Beings ◽  
Geological Disposal ◽  
Underground Caverns ◽  
Deep Underground

The safe disposal of high-level radioactive waste (HLW) is a major issue to ensure environmental protection and the sustainable development of the nuclear energy industry; it is also an equally important issue regarding nuclear safety. Deep-buried geological disposal is recognized worldwide as the safest and most feasible way to protect human beings and the environment. To satisfy the research functions, most underground research laboratories (URLs) for geological repositories are buried deeply, and their layout is quite complex. To research nonlinear deformation characteristics and failure mechanism of deep underground caverns in the process of construction, we developed an intelligent true triaxial non-uniform loading/unloading model test system. The system has the advantages of a large rated output, starting from zero pressure, cyclic loading and unloading, high loading accuracy and displacement test accuracy, and arbitrary adjustment of device size. We carried out a true three-dimensional physical model test, taking the URL for the deep-buried geological disposal of HLW in Beishan area, Gansu Province as the prototype. The nonlinear deformation characteristics and the law of displacement change of the underground laboratory caverns are reproduced. We observed the whole process, from the appearance of micro cracks to the expansion of the cracks and the collapse of the cavern group. This provides an important experimental basis for optimizing the design and construction of URL for the deep-buried geological disposal of HLW. The value and slope of displacement calculated by the numerical simulation are mainly the same as the experimental results of the geological model test, which validates the accuracy and reliability of the model test system in this study.

Model Test Study on Influences of Layered Rock Mass Dip Angle on Stability of Deep-Buried Tunnel

2011 ◽  
Vol 90-93 ◽  
pp. 2363-2371
Author(s):  
Bin Wei Xia ◽  
Ke Hu ◽  
Yi Yu Lu ◽  
Dan Li ◽  
Zu Yong Zhou
Keyword(s):  
Rock Mass ◽  
Physical Model ◽  
Model Test ◽  
Physical Models ◽  
Physical Model Test ◽  
Stress Distributions ◽  
Failure Characteristics ◽  
Layered Rock ◽  
Layered Rock Mass ◽  
Dip Angle

Physical models of layered rock mass with different dip angles are built by physical model test in accordance with the bias failure characteristics of surrounding rocks of layered rock mass in Gonghe Tunnel. Bias failure characteristics of surrounding rocks in thin-layered rock mass and influences of layered rock mass dip angle on stability of tunnel are studied. The research results show that failure characteristics of physical models generally coincide with those of surrounding rocks monitored from the tunnel site. The failure regions of surrounding rock perpendicular to the stratification planes are obviously larger than those parallel to. The stress distributions and failure characteristics in the surrounding rocks are similar to each physical model of different dip angles. The stress distributions and failure regions are all elliptic in shape, in which the major axis is in the direction perpendicular to the stratification planes while the minor axis is parallel to them. As a result, obvious bias failure of surrounding rocks has gradually formed. The physical model tests provide reliable basis for theoretical analysis on the failure mechanism of deep-buried layered rock mass.

Numerical Study of P-Waves Propagating across Deep Rock Masses Based on the Hoek–Brown Model

2020 ◽  
Vol 20 (2) ◽  
pp. 04019152
Author(s):  
Yun Zheng ◽  
Congxin Chen ◽  
Tingting Liu ◽  
Wei Zhang
Keyword(s):  
Numerical Study ◽  
Rock Masses ◽  
P Waves ◽  
Deep Rock
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