Numerical Analysis for Bolt Length Based on the Stress Response of Anchorage Surrounding Rock

2012 ◽  
Vol 204-208 ◽  
pp. 4481-4485
Author(s):  
Bin Wang ◽  
Fu Jun Zhao ◽  
Wen Bin Peng
Keyword(s):  
Numerical Simulation ◽  
Stress Response ◽  
Numerical Analysis ◽  
Bearing Capacity ◽  
Distribution Curve ◽  
Surrounding Rock ◽  
Effective Length ◽  
Plastic Failure ◽  
Deep Rock ◽  
Peak Value

The current researches on bolt length are rarely concerned with self-bearing characteristics of anchorage surrounding rock，its stress response is seldom used to analyze the bolt effective length. Tangential stress σθ of surrounding rock is sensitive to mechanical variation of surrounding rock plastic failure fields. When surrounding rock bolted, the distribution curve of σθ presents internal and external peak values from the surface rock to the deep rock, which is verified by numerical simulation. Internal peak value of σθ curve increases with the bolt length, which means the bearing capacity of surrounding rock in plastic failure division is improved, correspondingly, external peak value decreases which shows the supporting behavior of the deep rock is weakened. The results of numerical simulations prove that there exists an effective value of bolt length. If bolt length beyond it, the bearing capacity of anchorage surrounding rock cannot be improved obviously.

The Numerical Analysis on Stability of Deep Roadway Support System

2012 ◽  
Vol 193-194 ◽  
pp. 687-692
Author(s):  
Zhen Yan Xiao ◽  
Yu Liu
Keyword(s):  
Numerical Simulation ◽  
Numerical Analysis ◽  
Support System ◽  
Simulation Software ◽  
Surrounding Rock ◽  
Reinforcement Effect ◽  
Rock Bolts ◽  
Roadway Support

The effect of the roadway with no supporting and roadway that was reinforcement by rock bolts and anchor robs, anchor rod combined bolting shoring, anchor rod combined anchor rope and lining timbering was simulated by using numerical simulation software FLAC3D. The results showed that the deformation of no supporting roadway is maximal, and the maximal position is vault. The displacement of top floor and two side decreases after supported, which can reinforce surrounding rock. The reinforcement effect of the anchor rod combined anchor rope and lining timbering is best.

scholarly journals Comparative Study on Two Types of Nonpillar Mining Techniques by Roof Cutting and by Filling Artificial Materials

2019 ◽  
Vol 2019 ◽  
pp. 1-15 ◽  
Author(s):  
Enze Zhen ◽  
Yubing Gao ◽  
Yajun Wang ◽  
Siming Wang
Keyword(s):  
Numerical Simulation ◽  
High Efficiency ◽  
Simulation Analysis ◽  
Surrounding Rock ◽  
Support Pressure ◽  
Hydraulic Support ◽  
Pressure Relief ◽  
Rock Structure ◽  
Coal Pillars ◽  
Peak Value

Gob-side entry retaining is an environmentally friendly nonpillar mining technology with high efficiency and safety. With the continuous exploration of the gob-side entry retained by filling (GERF) with roadside supports, the GERF has enabled nonpillar mining. However, dense roadside supports or filled artificial pillars become subject to the pressure of roof pressure instead of coal pillars, which causes problems. Recently, an original innovative gob-side entry retaining technology by roof cutting and pressure relief (RCPR) was developed and extensively implemented in China’s coal production. The gob-side entry formed by different retaining methods has exhibited some differences in the strata behaviors and the results of retained roadways. Via industrial case and numerical simulation, this study explored the influence of entry retaining methods on the results of the entry retained. The results indicate that the total deformation of the surrounding rock of the GERF is larger and more severe; the convergence between the roof and floor and the entry sides displacement is 885 mm and 216 mm, respectively; the hydraulic support pressure near the retained entry is larger; and the peak value is 38.7 MPa. The deformation of the surrounding rock by RCPR is relatively small; the convergence between the roof and the floor and the entry sides displacement is 351 mm and 166 mm, respectively; the hydraulic support pressure near the retained entry is weakened to a certain extent; the peak value is 32.2 MPa; and the peak pressure is reduced by 16.8% compared with the GERF. A numerical simulation analysis reveals the following findings: RCPR changes the surrounding rock structure of a gob-side entry, optimizes the surrounding rock stress environment, and belongs to active pressure-relief entry retaining; the GERF does not adjust the surrounding rock structure of a gob-side entry and belongs to passive pressure-resistance entry retaining; and the surrounding rock of a gob-side entry is significantly affected by pressure. These two methods of gob-side entry retaining have different effects on the surrounding rock of the entry retained. This study can contribute to an exploration of the strata behaviors and the results of a retained roadway by the GERF or RCPR method.

scholarly journals Numerical Investigation of Gob-Side Entry Retaining through Precut Overhanging Hard Roof to Control Rockburst

2018 ◽  
Vol 2018 ◽  
pp. 1-10 ◽  
Author(s):  
Xiaoming Sun ◽  
Li Gan ◽  
Zhao Chengwei ◽  
Tang Jianquan ◽  
He Manchao ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Abutment Pressure ◽  
Feasibility Studies ◽  
Main Roof ◽  
Surrounding Rock ◽  
Distribution Characteristics ◽  
Hard Roof ◽  
Working Face ◽  
Stress Fluctuation ◽  
Peak Value

Gob-side entry retaining through precut overhanging hard roof (GERPOHR) method is one of the commonly used methods for nonpillar mining. However, feasibility studies of controlling rockburst by this method are few. Rockburst occurs in hard thick strata with a higher probability, larger scale, and higher risk. To better understand the GERPOHR method is beneficial for rockburst mitigation. In this paper, the design of GERPOHR was first introduced. And the layout of the working face was optimized. Then, based on the numerical simulation, the stress and displacement distribution characteristics were compared under the condition of conventional mining and GERPOHR method. The research shows that the intervals of main roof weighting could be decreased through the precut overhanging hard roof method. And the peak value of abutment pressure decreased. Meanwhile, the energy accumulation and the stress fluctuation could be alleviated in roadway surrounding rock.

Numerical Analysis of Damage for Y-Shape Tunnel

2011 ◽  
Vol 368-373 ◽  
pp. 2517-2520
Author(s):  
Da Ming Lin ◽  
Yan Jun Shang ◽  
Guo He Li ◽  
Yuan Chun Sun
Keyword(s):  
Numerical Simulation ◽  
Rock Mass ◽  
Numerical Analysis ◽  
Plastic Zone ◽  
Comprehensive Analysis ◽  
Surrounding Rock ◽  
Tunnel Construction ◽  
Deformation And Failure ◽  
Single Beam ◽  
Flac 3D

There are many effective researches about tunnel at home and abroad, because the complexity of design and construction for Y-shape tunnel, in public there is no research about it yet, with the background of nanliang-tunnel which merge two single-beam into a two-lane tunnel as Y-shape. This paper obtains the rock mass mechanics parameters on the basis of nonlinear Hoek-Brown criterion first, and has a numerical simulation according the tunnel construction with FLAC-3D. we arrange many monitor sections in this model and discuss the law of deformation and failure in different section, at last have a comprehensive analysis of displacement, stress, plastic zone of different sites which caused by tunnel construction and discover that: with the distance of two single tunnels decreased, the interaction caused by the merging increase together with the compressive stress, tensile stress. The displacements of surrounding rock increase corresponding, the amplitude of variation is up to 44.8%, After the two-lane tunnel is 15m long, the stress and displacements redistribution of surrounding rock become stable.

Study on the Mechanical Behavior of Excavation and Support Construction of Shallow Tunnel

2013 ◽  
Vol 353-356 ◽  
pp. 1693-1698
Author(s):  
Zhen Xing Yang ◽  
Liang Song ◽  
Hao Wang ◽  
Yu Yong Jiao ◽  
Shu Cai Li ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Mechanical Behavior ◽  
Rock Pressure ◽  
Simulation Method ◽  
Internal Force ◽  
Surrounding Rock ◽  
Shallow Tunnel ◽  
Maximum Value ◽  
Surrounding Rock Pressure ◽  
Peak Value

In this paper, the mechanical behavior of excavation and support construction of Weishe tunnel, which is a section of the Yangwu expressway, is studied quantitatively using 3D finite difference numerical simulation method. A sequential excavation method is used and the results show that the vault settlement occurs mainly on the phase of upper bench excavation. The convergences of upper and lower sidewalls occur mainly on the phase of lower bench excavation. During the construction, the surrounding rock pressure in the vault and sidewall of the tunnel decrease. Axial force of anchor reaches the maximum value after the finish of second lining. However, the surrounding rock pressure and internal force of steel arch reach the maximum value after completing the upper bench excavation, and then become as smaller as half of the peak value during the lower bench excavation.

Numerical Analysis of Initial Support and Secondary Lining Contact Pressure of Phyllite Tunnel

2014 ◽  
Vol 884-885 ◽  
pp. 675-678
Author(s):  
Xin Zhe Li ◽  
Geng Feng Wang ◽  
Xin Liang Li ◽  
Zhong Rong Zhu
Keyword(s):  
Numerical Simulation ◽  
Numerical Analysis ◽  
Contact Pressure ◽  
Surrounding Rock ◽  
Before And After ◽  
Initial Support ◽  
Secondary Lining

Taking Jin Chuan phyllite tunnel as the research object, and based on numerical simulation of surrounding rock graded III, IV and V, the paper studied the stress characteristics of initial support and four other representative locations such as two arch vault, arch spandrel, arch haunch, and arch foot during and after the process of construction. The paper focuses on the stress characteristics of secondary lining in different locations after stability and the change of stress in different locations of initial lining before and after the secondary lining construction.

scholarly journals Coupled Hydraulic-Thermal Modelling and Related Numerical Analysis on Rock Fractures

Geofluids ◽  
2020 ◽  
Vol 2020 ◽  
pp. 1-9
Author(s):  
Yongjian Pan ◽  
Huajun Wang ◽  
Qiang Liu
Keyword(s):  
Numerical Simulation ◽  
Rock Mass ◽  
Numerical Analysis ◽  
Coupling Effect ◽  
Flow Speed ◽  
Engineering Practice ◽  
Rock Fractures ◽  
Thermal Coupling ◽  
Water Head ◽  
Deep Rock

Hydraulic-thermal coupling is a key problem in rock mass engineering, especially in the disposal of nuclear wastes in deep rock mass. To accurately describe the coupling action of rock mass when under the interaction of hydraulic stress and thermal, the hydraulic-thermal coupling solving methods were proposed in this paper; in addition, the corresponding hydraulic-thermal coupling program FRHT3D was complied. Consequently, the numerical simulation was performed, it can be concluded that the flow speed is faster when the coupling effect is considered at the unstable seepage stage, and the seepage coupling solution is larger than that of uncoupling. Furthermore, when the coupling effects are considered, the permeable water head solution is much larger than that of the uncoupling solution at the unstable seepage stage. The proposed hydraulic-thermal coupling solving methods and programs can be applied to rock mass engineering practice.

scholarly journals Research on Plastic Zone Evolution Law of Surrounding Rock of Gob-Side Entry Retaining under Typical Roof Conditions in Deep Mine

2020 ◽  
Vol 2020 ◽  
pp. 1-13
Author(s):  
Jingke Wu ◽  
Yun Dong ◽  
Yang Jiang ◽  
Yushun Yang ◽  
Huasheng Sun ◽  
...  
Keyword(s):  
Plastic Zone ◽  
Bearing Capacity ◽  
Surrounding Rock ◽  
Deep Mine ◽  
Damage Area ◽  
Structure Control ◽  
Plastic Failure ◽  
Hard Roof ◽  
Immediate Roof ◽  
Coal Rock

To solve the control problem of the surrounding rock of gob-side entry retaining under typical roof conditions in deep mines, we conduct theoretical analysis, numerical simulation, and actual measurements. Starting from the plastic zone of the surrounding rock, the serious damage area, the degree and scope of damage, and the dynamic evolution process of the surrounding rock of the gob-side entry retaining are systematically analyzed under four typical roof conditions in deep mines; the expansion and evolution laws of the plastic zone of the surrounding rock are expounded; and a key control technology is proposed. The results indicate that (1) the plastic failure of surrounding rock was concentrated mainly on the coal side and on the floor, especially in the filling body. The plastic zone of the surrounding rock of the gob-side entry retaining with the thick immediate roof was widely distributed and deep, but the plastic failure of the filling body was not obvious. The plastic failure of the surrounding rock of the gob-side entry retaining with the compound roof was mainly concentrated on the roof, filling body, and floor of the filling area. (2) According to the typical roof conditions of the deep gob-side entry retaining, the order of the degree of damage to the surrounding rock was as follows: thick immediate roof, compound roof, thin immediate roof, and thick-hard roof. (3) A “multisupport structure” control system is proposed for the gob-side entry retaining in a deep mine, including measures for enhancing the bearing performance of the anchorage system, increasing the strength of the cataclastic coal-rock mass, enhancing the bearing capacity of the filling body, and increasing the bearing capacity on the tunnel side. The proposed technology was applied to the deep gob-side entry retaining project in the east area of Panyi Mine, and it effectively fulfilled the reuse requirements of gob-side entry retaining in deep mines.

Numerical Analysis of Construction Method in Shallow-Buried Large-Section Loess Tunnel

2014 ◽  
Vol 580-583 ◽  
pp. 997-1000 ◽  
Author(s):  
Zhi Jie Sun
Keyword(s):  
Numerical Simulation ◽  
Numerical Analysis ◽  
Ground Surface ◽  
Construction Method ◽  
Surrounding Rock ◽  
3D Numerical Simulation ◽  
Large Section ◽  
Research Results ◽  
Construction Methods ◽  
Ground Surface Settlement

To research the deformation regularity of large section loess tunnel in construction procession with different construction methods, 3D Numerical Simulation is applied and the large-section loess tunnel of highway is taken as an example. Comparing deformation regularity of surrounding rock in three types of construction method conditions, the research results show that:The CRD method takes precedence in the condition of the convergence of surrounding rock is large. The both sides heading method takes precedence in the condition of ground surface settlement is large.

Numerical Simulation of Failure of Overburden in Coal Mining under Reservoir

2011 ◽  
Vol 383-390 ◽  
pp. 6378-6382
Author(s):  
Zhong Chang Wang ◽  
De Shen Zhao
Keyword(s):  
Numerical Simulation ◽  
Shear Stress ◽  
Tensile Stress ◽  
Coal Mining ◽  
Surrounding Rock ◽  
Horizontal Movement ◽  
Subsidence Basin ◽  
Limit Value ◽  
Peak Value ◽  
Mining Height

The Water-flowing fractured zone’s height and its distribution has an important effect on stability of the surrounding rock and the safety in the subsequent production under reservoir. In the paper the Drucker-Prager yielding law is used. The limit value of tensile stress and shear stress is used to judge the water-flowing fractured zone’s height and its distribution. The fitting formula is obtained by origin software under different advance of the work face. The peak value of horizontal movement is 1.13m. The symmetrical subsidence basin is formed in the center of work face. The peak value of subsidence is 3.86m. The sum of surface subsidence accounts for about 43 percent of the mining height. The advance of around 300m is the distance that the water flowing fractured zone’s height reaches the highest value. The biggest height of water- flowing fractured zone is 146m.

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