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.

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.

scholarly journals Control of Gob-Side Roadway with Large Mining Height in Inclined Thick Coal Seam: A Case Study

2021 ◽  
Vol 2021 ◽  
pp. 1-14
Author(s):  
Xie Fuxing
Keyword(s):  
Numerical Simulation ◽  
Coal Pillar ◽  
Simulation Software ◽  
Surrounding Rock ◽  
Mine Pressure ◽  
Thick Coal Seam ◽  
Working Face ◽  
Rock Structure ◽  
Large Mining Height ◽  
Mining Height

The gob-side roadway of 130205, a large-mining-height working face in the Yangchangwan coal mine, was investigated in terms of the mine pressure law and support technology for large mining heights and narrow coal pillars for mining roadways. The research included field investigations, theoretical analysis, numerical simulation, field tests, and other methods. This paper analyzes the form of movement for overlying rock structure in a gob-side entry with a large mining height and summarizes the stress state and deformation failure characteristics of the surrounding rock. The failure mechanism of the surrounding rock of the gob-side roadway and controllable engineering factors causing deformation were analyzed. FLAC3D numerical simulation software was used to explore the influence law of coal pillar width, working face mining height, and mining intensity on the stability of the surrounding rock of the gob-side roadway. Ensuring the integrity of the coal pillar, improving the coordination of the system, and using asymmetric support structures as the core support concept are proposed. A reasonably designed support scheme for the gob-side roadway of the working face for 130205 was conducted, and a desirable engineering effect was obtained through field practice verification.

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.

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.

Laws of Formation and Evolution of Pressure Arch in Coal Mining Adjoining Rock

2011 ◽  
Vol 243-249 ◽  
pp. 2596-2600
Author(s):  
Xiao Li Du ◽  
Hong Wei Song ◽  
Jie Chen
Keyword(s):  
Numerical Simulation ◽  
Coal Mining ◽  
Vertical Direction ◽  
Stress Transfer ◽  
Surrounding Rock ◽  
Coefficient Variation ◽  
Working Face ◽  
Formation And Evolution ◽  
Mining Face ◽  
Adjoining Rock

Based on numerical simulation of computing Software ANSYS, the curve of arching coefficient variation of pressure arch due to actual mining was analyzed aiming to a special mining face, the law of stress transfer and change in surrounding rock was discussed, and the evolving features and characteristics of pressure arch was obtained. The analysis and discussion show the following facts: Arch body will become thicker and stress in the arch body increases with working face’s driving distance increasing; the morphology of pressure arch transits from ellipsoid with long axis in the vertical direction to ellipsoid with long axis in the horizontal direction along the trend of working face; along the tendency of working face, the morphology of pressure arch is a ellipsoid with long axis in the vertical direction.

scholarly journals Effects of Coal Mining Height and Width on Overburden Subsidence in Longwall Pier-Column Backfilling

2021 ◽  
Vol 11 (7) ◽  
pp. 3105
Author(s):  
Xiaozhen Wang ◽  
Jianlin Xie ◽  
Jialin Xu ◽  
Weibing Zhu ◽  
Limin Wang
Keyword(s):  
Numerical Simulation ◽  
Coal Seam ◽  
Coal Mining ◽  
Control Effect ◽  
Physical Similarity ◽  
Thin Coal Seam ◽  
Theoretical Support ◽  
Working Face ◽  
Mining Model ◽  
Mining Height

Longwall pier-column backfilling is a partial backfilling technique initially designed in thin coal seam mines. With the increase of mining intensity, the mining height and width of the backfilling working face will also increase. It is necessary to analyze how changes in working face dimensions influence the control effect of overburden subsidence in pier-column backfilling. In this study, a mining model with a combination of 25 conditions (five different mining heights (1~3 m) × five different mining widths (80~240 m)) was designed using a FLAC3D(Vision 5.0) numerical simulation. The simulation was used to analyze the control effect of overburden subsidence with varying mining heights and widths. In addition, according to the field working face conditions, two physical similarity models were performed to explore the overburden subsidence law in pier-column backfilling with different mining heights and widths. It was observed from the above study that mining heights and widths will have a different influence on the overburden subsidence in longwall pier-column backfilling. The result of this study provides strong theoretical support for evaluating the control effect of overburden subsidence in longwall pier-column backfilling.

scholarly journals Theoretical Analysis on Stress and Deformation of Overburden Key Stratum in Solid Filling Coal Mining Based on the Multilayer Winkler Foundation Beam Model

Geofluids ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-15
Author(s):  
Chao Ma ◽  
Xiaoqian Guo ◽  
Lianying Zhang ◽  
Aihong Lu ◽  
Xianbiao Mao ◽  
...  
Keyword(s):  
Shear Stress ◽  
Elastic Modulus ◽  
Layer Thickness ◽  
Coal Mining ◽  
Winkler Foundation ◽  
Beam Model ◽  
Soft Layer ◽  
Key Strata ◽  
Key Stratum ◽  
Mining Height

Solid backfill coal mining (SBCM) is a green mining technology which can effectively alleviate the environmental problems induced by traditional coal mining techniques, such as surface subsidence, water resources loss, coal gangue occupation, and pollution. In this study, a multilayer Winkler foundation beam model for the overburden key strata is proposed, and the model with two key strata is solved. The subsidence, rotating angle, inner force, and stress of the overburden key strata are systematically analyzed under various backfill elastic modulus, mining height, and soft layer thickness. The results show that the subsidence of the key strata exhibit “basin”-shape curves, and the backfill elastic modulus, mining height, and the thickness of the soft strata have significant influences on the subsidence of the key strata. The shear stress, horizontal stress, and vertical stress of key stratum can be effectively reduced by increasing the backfill elastic modulus. The increase of mining height has little influence on the stress of key stratum that close to the coal seam (key stratum #1), but has a significant effect on the stress of key stratum that above the soft layers (key stratum #2). On the contrary, the effect of increasing soft layer thickness on the stress of key stratum is opposite to that of increasing mining height. In addition, the shear failure of key stratum #1 at mining boundary and the tensile failures on both sides of mining boundary should be preferentially considered in SBCM engineering design. Due to the low shear stress level of key stratum #2, the tensile failure on both sides of the mining boundary should be mainly considered.

Visualization of separation and reattachment in an incident shock-induced interaction

2021 ◽  
pp. 095441002098349
Author(s):  
Yun Jiao ◽  
Chengpeng Wang
Keyword(s):  
Numerical Simulation ◽  
Shock Wave ◽  
Shear Stress ◽  
Separation Bubble ◽  
Incident Shock ◽  
Incident Shock Wave ◽  
Bottom Wall ◽  
Surface Shear Stress ◽  
Surface Shear ◽  
Oil Flow

An experimental study is conducted on the qualitative visualization of the flow field in separation and reattachment flows induced by an incident shock interaction by several techniques including shear-sensitive liquid crystal coating (SSLCC), oil flow, schlieren, and numerical simulation. The incident shock wave is generated by a wedge in a Mach 2.7 duct flow, where the strength of the interaction is varied from weak to moderate by changing the angle of attack α of the wedge from 8° and 10° to 12°. The stagnation pressure upstream was set to approximately 607.9 kPa. The SSLCC technique was used to visualize the surface flow characteristics and analyze the surface shear stress fields induced by the initial incident shock wave over the bottom wall and sidewall experimentally which resolution is 3500 × 200 pixels, and the numerical simulation was also performed as the supplement for a clearer understanding to the flow field. As a result, surface shear stress over the bottom wall was visualized qualitatively by SSLCC images, and flow features such as separation/reattachment and the variations of position/size of separation bubble with wedge angle were successfully distinguished. Furthermore, analysis of shear stress trend over the bottom wall by a hue value curve indicated that the relative magnitude of shear stress increased significantly downstream of the separation bubble compared with that upstream. The variation trend of shear stress was consistent with the numerical simulation results, and the error of separation position was less than 2 mm. Finally, the three-dimensional schematic of incident shock-induced interaction has been achieved by qualitative summary by multiple techniques, including SSLCC, oil flow, schlieren, and numerical simulation.

Reasonable Entry Layout of Lower Seam in Multi-Seam Mining Based on Numerical Simulation

2013 ◽  
Vol 295-298 ◽  
pp. 2980-2984
Author(s):  
Xiang Qian Wang ◽  
Da Fa Yin ◽  
Zhao Ning Gao ◽  
Qi Feng Zhao
Keyword(s):  
Numerical Simulation ◽  
Stress Distribution ◽  
Coal Seam ◽  
Coal Mine ◽  
Abutment Pressure ◽  
Surrounding Rock ◽  
Geological Conditions ◽  
Seam Mining

Based on the geological conditions of 6# coal seam and 8# coal seam in Xieqiao Coal Mine, to determine reasonable entry layout of lower seam in multi-seam mining, alternate internal entry layout, alternate exterior entry layout and overlapping entry layout were put forward and simulated by FLAC3D. Then stress distribution and displacement characteristics of surrounding rock were analyzed in the three ways of entry layout, leading to the conclusion that alternate internal entry layout is a better choice for multi-seam mining, for which makes the entry located in stress reduce zone and reduces the influence of abutment pressure of upper coal seam mining to a certain extent,. And the mining practice of Xieqiao Coal Mine tested the results, which will offer a beneficial reference for entry layout with similar geological conditions in multi-seam mining.

Sign in / Sign up

Export Citation Format

Share Document