A New Yielding Bolt for Rock Support in High Stress Rock Masses

2012 ◽  
Vol 204-208 ◽  
pp. 366-369 ◽  
Author(s):  
Gang Wang ◽  
Xue Zhen Wu ◽  
Yu Jing Jiang
Keyword(s):  
Rock Mass ◽  
Theoretical Analysis ◽  
Large Deformations ◽  
High Stress ◽  
Surrounding Rock ◽  
Rock Support ◽  
Stability Of Surrounding Rock ◽  
History Of ◽  
The Stability ◽  
Energy Absorbing

High stress in the surrounding rock mass causes serious stability problems. The applied support system used in this conduction should be able to carry high loads and also accommodate large deformations without experiencing serious damage. In this paper, a brief overview of the history of yielding/energy-absorbing rock bolts is provided. And then, a new yielding bolt invented by the author is introduced in detail, including its layout and principle. Theoretical analysis shows that the bolt has large load-bearing and deformation capacities, thereby absorbing a large amount of energy to maintain the stability of surrounding rock.

Hydro-Mechanical Coupled Analysis of the Stability of Surrounding Rock Mass of Underground Water-Sealed Oil Storage

2013 ◽  
Vol 405-408 ◽  
pp. 402-405 ◽  
Author(s):  
Yun Jie Zhang ◽  
Tao Xu ◽  
Qiang Xu ◽  
Lin Bu
Keyword(s):  
Rock Mass ◽  
Underground Water ◽  
Surrounding Rock ◽  
Comsol Multiphysics ◽  
Coupled Analysis ◽  
Coupling Theory ◽  
Oil Storage ◽  
Stability Of Surrounding Rock ◽  
Straight Wall ◽  
The Stability

Based on the fluid-solid coupling theory, we study the stability of surrounding rock mass around underground oil storage in Huangdao, Shandong province, analyze the stress of the surrounding rock mass around three chambers and the displacement change of several key monitoring points after excavation and evaluate the stability of surrounding rock mass using COMSOL Multiphysics software. Research results show that the stress at both sides of the straight wall of cavern increases, especially obvious stress concentration forms at the corners of the cavern, and the surrounding rock mass moves towards the cavern after excavation. The stress and displacement of the surrounding rock mass will increase accordingly after setting the water curtains, but the change does not have a substantive impact on the stability of surrounding rock mass.

The Research on Application of Strength Reduction Finite Element Method in Stability Analysis of Weak Intercalated Rock Tunnel

2011 ◽  
Vol 255-260 ◽  
pp. 1926-1929
Author(s):  
Da Kun Shi ◽  
Yang Song Zhang
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Rock Mass ◽  
Safety Factor ◽  
Slip Surface ◽  
Strength Reduction ◽  
Surrounding Rock ◽  
Stability Of Surrounding Rock ◽  
The Stability ◽  
Element Method

Based on geologic condition of one tunnel surrounding rock mass, systematic numerical tests had been carried out to study the stability of surrounding rock mass with different distributions of weak intercalated rock by the FEM software ABAQUS and strength reduction finite element method. Some quantificational results about the stability of surrounding rock mass were summarized. And the safety factor and latent slip surface were worked out. The stability of surrounding rock mass was judged by strength reduction finite element method. According to the analysis above, it’s known that the discrepancy of two rules is small; the safety factor is the lowest when weak intercalated rock in vault, and when at bottom, it’s higher than that of in vault. The conclusion can be used to guide the procedure of construction and ensure the safety.

A Study on Stability of Expressway Tunnel Surrounding Rock Containing Weak Intercalated Rock

2010 ◽  
Vol 168-170 ◽  
pp. 2543-2547
Author(s):  
Da Kun Shi ◽  
Yang Song Zhang
Keyword(s):  
Rock Mass ◽  
Plastic Zone ◽  
Surrounding Rock ◽  
Constitutive Law ◽  
Numerical Tests ◽  
Stability Of Surrounding Rock ◽  
Strain Type ◽  
Deformation Stress ◽  
Plain Strain ◽  
The Stability

Weak intercalated rock plays an important role in the stability of engineering rock mass. It controls the mechanism of deformation and breakage of rocks. Systematic numerical tests have been carried out to study the stability of surrounding rock mass with different distributions of weak intercalated rock has been analyzed by the FEM software ABAQUS. All of the numerical modelings are plain-strain type with elasto-plastic constitutive law and Drucker-Prager failure criterion. Some quantificational results about the influence of weak intercalated rock are summarized, especially the influence on the deformation, stress of surrounding rocks and plastic zone. Because of weak intercalated rock, the stress of surrounding rock appears the character of discontinuity. In addition, the distribution of plastic zone is also affected. When weak intercalated rocks exist in vault, spandrel and bottom, the situation of surrounding rock is comparatively unfavorable. These results have a certain role in guiding significance to the site selection and layout, the majorization of supporting system and the construction of tunnel of the same kind.

Comparison Optimization Analysis of the Location of Power House under Complex Geological Structure

2006 ◽  
Vol 306-308 ◽  
pp. 1455-1460
Author(s):  
Jing Zeng ◽  
Qian Sheng ◽  
Qing Chun Zhou
Keyword(s):  
Rock Mass ◽  
Geological Structure ◽  
Surrounding Rock ◽  
Obvious Effect ◽  
Power House ◽  
Mass Comparison ◽  
Geological Conditions ◽  
Stability Of Surrounding Rock ◽  
Complex Geological Structure ◽  
The Stability

The power house of Yantan extended hydropower project, with complex geological conditions such as fault f211 below the power house and quartzite on top of it, is a huge underground cavern with large span and high wall. In order to evaluate the stability of the power house surrounded by such complex geological structure, the numerical simulation excavation of power house with different location schemes were studied by the elasto-plastic 2D FEM method. The deformation and evolutive process of the stress with the progress of excavation were analyzed. On the condition ensuring the whole stability of surrounding rock mass, comparison optimization analyses were conducted on the power house location scheme. The rational location scheme was demonstrated. The final analyses results show that: (1) The mechanical properties of quartzite and its relative location to the power house has no obvious influence to the stability of surrounding rock mass.(2) The f211 is the main bad geological structure which affect the stability of power house. (3) The case of moving 10m upward of power house is the most rational scheme for the whole stability of power house. (4) The Supporting measures, which would has an obvious effect in controlling the influence on the stability of surrounding rock mass by weak geological structure, are suggested at the out-crop of f211.

Stability Analysis of Diversion Tunnels in Jinping II Hydropower Station Project

2008 ◽  
Vol 575-578 ◽  
pp. 1287-1292
Author(s):  
Chuan Qing Zhang ◽  
Xia Ting Feng ◽  
Hui Zhou ◽  
Shu Ling Huang ◽  
Quan Jiang
Keyword(s):  
Rock Mass ◽  
High Stress ◽  
Great Depth ◽  
In Situ Stress ◽  
Surrounding Rock ◽  
Hydropower Plant ◽  
Linear Regression Method ◽  
Technical Problems ◽  
The Stability ◽  
In Situ Stress Field

Surrounding rock mass stability is one of the key technical problems in the design of the diversion tunnels in Jinping II Hydropower Plant Project. The major difficulties lie in three facts: (1) high stress induced by the great depth; (2) the brittle failure characters of marble; (3) the interaction of these four tunnels. A systemic procedure is introduced in this paper. Firstly, the integration of the code FLAC3D and the multivariate linear regression method is adopted to back analyze the in situ stress field. Then the mechanical parameters of the surrounding rock mass are back analyzed based on the PSO (Particle Swarm Optimization) algorithm and the code FLAC3D. The stress release method is adopted in the numerical analysis of the excavating and supporting process of tunnels by the code FLAC3D. Finally, the multi indexes integration method is presented to analyze and evaluate the stability of the tunnels and to validate the rationality of the design scheme.

scholarly journals Investigation of Deep Shaft-Surrounding Rock Support Technology Based on a Post-Peak Strain-Softening Model of Rock Mass

2021 ◽  
Vol 12 (1) ◽  
pp. 253
Author(s):  
Jianjun Zhang ◽  
Yang Wang ◽  
Baicong Yao ◽  
Dongxu Chen ◽  
Chuang Sun ◽  
...  
Keyword(s):  
Rock Mass ◽  
Strain Softening ◽  
Jointed Rock ◽  
Jointed Rock Mass ◽  
Surrounding Rock ◽  
Peak Strain ◽  
Rock Support ◽  
Support Structure ◽  
The Stability ◽  
Surrounding Rock Deformation

To control the large deformation that occurs in deep shaft-surrounding rock, the post-peak strain-softening characteristics of deep jointed rock mass are discussed in detail. An equivalent post-peak strain-softening model of jointed rock mass is established based on continuum theory and the geological strength index surrounding rock grading system, and numerical simulations are performed using FLAC3D software. The convergence-constraint method is used to analyze the rock support structure interaction mechanism. A composiste support technique is proposed in combination with actual field breakage conditions. During the initial support stage, high-strength anchors are used to release the rock stress, and high-stiffness secondary support is provided by well rings and poured concrete. This support technology is applied in the accessory well of a coal mine in Niaoshan, Heilongjiang, China. The stability of the surrounding rock support structure is calculated and analyzed by comparing the ideal elastic-plastic model and equivalent jointed rock mass strain-softening model. The results show that a support structure designed based on the ideal elastic-plastic model cannot meet the stability requirements of the surrounding rock and that radial deformation of the surrounding rock reaches 300 mm. The support structure designed based on the equivalent joint strain-softening model has a convergence rate of surrounding rock deformation of less than 1 mm/d after 35 days of application. The surrounding rock deformation is finally controlled at 140 mm, indicating successful application of the support technology.

Application of ABAQUS in Surrounding Rock Stability Analysis of Shallow Large Cross-Section Tunnel

2015 ◽  
Vol 777 ◽  
pp. 8-12 ◽  
Author(s):  
Lin Zhen Cai ◽  
Cheng Liang Zhang
Keyword(s):  
Numerical Simulation ◽  
Rock Mass ◽  
Strong Support ◽  
Surrounding Rock ◽  
Tunnel Engineering ◽  
Tunnel Excavation ◽  
Rock Stability ◽  
Rock Bolting ◽  
Excavation Support ◽  
The Stability

HuJiaDi tunnel construction of Dai Gong highway is troublesome, the surrounding-rock mass give priority to full to strong weathering basalt, surrounding rock integrity is poor, weak self-stability of surrounding rock, and tunnel is prone to collapse. In order to reduce disturbance, taking advantage of the ability of rock mass, excavation adopt the method of "more steps, short footage and strong support". The excavation method using three steps excavation, The excavation footage is about 1.2 ~ 1.5 m; The surrounding rock bolting system still produce a large deformation after completion of the first support construction, it shows that the adopted support intensity cannot guarantee the stability of the tunnel engineering. Using ABAQUS to simulate tunnel excavation support, optimizing the support parameters of the tunnel, conducting comparative analysis with Monitoring and Measuring and numerical simulation results, it shows that the displacement - time curves have a certain consistency in numerical simulation of ABAQUS and Monitoring and Measuring.

Judgement Method for Surrounding Rock Stability of Guanjiao Tunnel Based on Catastrophe Theory

2011 ◽  
Vol 90-93 ◽  
pp. 2307-2312 ◽  
Author(s):  
Wen Jiang Li ◽  
Su Min Zhang ◽  
Xian Min Han
Keyword(s):  
Plastic Strain ◽  
Catastrophe Theory ◽  
Soft Rock ◽  
Surrounding Rock ◽  
In Situ Monitoring ◽  
Engineering Practice ◽  
Stability Of Surrounding Rock ◽  
The Stability ◽  
Rock Tunnel

The stability judgement of surrounding rock is one of the key jobs in tunnel engineering. Taking the Erlongdong fault bundle section of Guanjiao Tunnel as the background, the stability of surrounding rock during construction of soft rock tunnel was discussed preliminarily. Based on plastic strain catastrophe theory, and combining numerical results and in-situ data, the limit displacements for stability of surrounding rock were analyzed and obtained corresponding to the in-situ monitoring technology. It shows that the limit displacements obtained corresponds to engineering practice primarily. The plastic strain catastrophe theory under unloading condition provides new thought for ground stability of deep soft rock tunnel and can be good guidance and valuable reference to construction decision making and deformation managing of similar tunnels.

scholarly journals Numerical Simulation on Large Deformation of Weak Rock Mass Tunnel Under High Geostress

2018 ◽  
Vol 175 ◽  
pp. 03025
Author(s):  
Feng Zhou ◽  
Hongjian Jiang ◽  
Xiaorui Wang
Keyword(s):  
Rock Mass ◽  
Large Deformation ◽  
Lateral Pressure ◽  
Simulation Analysis ◽  
Pressure Coefficient ◽  
Surrounding Rock ◽  
Analog Simulation ◽  
Lateral Pressure Coefficient ◽  
High Geostress ◽  
The Stability

The problem about the stability of tunnel surrounding rock is always an important research object of geotechnical engineering, and the right or wrong of the result from stability analysis on surrounding rock is related to success or failure of an underground project. In order to study the deformation rules of weak surrounding rock along with lateral pressure coefficient and burying depth varying under high geostress and discuss the dynamic variation trend of surrounding rock, the paper based on the application of finite difference software of FLAC3D, which can describe large deformation character of rock mass, analog simulation analysis of surrounding rock typical section of the class II was proceeded. Some conclusions were drawn as follows: (1) when burying depth is invariable, the displacements of tunnel surrounding rock have a trend of increasing first and then decreasing along with increasing of lateral pressure coefficient. The floor heave is the most sensitive to change of lateral pressure coefficient. The horizontal convergence takes second place. The vault subsidence is feeblish to change of lateral pressure coefficient. (2) The displacements of tunnel surrounding rock have some extend increase along with increasing of burying depth. The research conclusions are very effective in analyzing the stability of surrounding rock of Yunling tunnel. These are going to be a reference to tunnel supporting design and construction.

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