Strata Behaviors of Fully-Mechanized Sublevel Caving Face Based on Similar Simulation Test

2013 ◽  
Vol 734-737 ◽  
pp. 638-643
Author(s):  
Hua Wen Lv
Keyword(s):  
Abutment Pressure ◽  
Main Roof ◽  
Test Model ◽  
Simulation Test ◽  
Slow Increase ◽  
Working Face ◽  
Sublevel Caving ◽  
Pressure Peak ◽  
Similar Simulation Test ◽  
Similar Simulation

in view of research situations of the fully mechanized sublevel caving, the similar simulation test model for fully mechanized sublevel caving was presented. During the top-coal caving process, variation of top-coal subsidence and abutment pressure were measured. Consequently, the ground pressure behavior of fully mechanized sublevel caving was analyzed. The following conclusions can be reached: (1) top coal subsidence experiences the process of slow increase, trend to aggressive and sharp increase; (2) undulate change as well as decay after reaching the peak of abutment pressure is appeared with the advance of working face, strata behaviors of main roof displays smoothly; (3) on account of cushion above hydraulic support, influence of dynamic load during periodic weighting such as rock burst can be eased and abutment pressure peak moves forward, consequently, strata behaviors in the working face presents smoothly.

Study on Abutment Pressure Distribution Law of Fully-Mechanized Sublevel Caving Face in Extra-Thickness

2015 ◽  
Vol 1094 ◽  
pp. 405-409
Author(s):  
Lei Yu
Keyword(s):  
Pressure Distribution ◽  
Abutment Pressure ◽  
Distribution Law ◽  
Working Face ◽  
Sublevel Caving ◽  
Coal Wall ◽  
Pressure Peak ◽  
Cutting Height ◽  
Coal Seam Thickness ◽  
Peak Value

Based on field observation, analogy simulation and theoretical analysis, the abutment pressure distribution law of fully-mechanized sublevel caving face with extra-thickness was studied. The results showed that: Different instability type of the structure ‘Combined cantilever beam-articulated rock beam’ in fully-mechanized sublevel caving roof led to cyclical changes of abutment pressure; with an invariable coal seam thickness and increasing cutting height, abutment pressure peak value tended to stabilize after reaching the maximum, but as the working face advancing its location transferred to the front of coal wall working face and the influence region of abutment pressure increased; with an invariable cutting height and increasing once mining thickness, abutment pressure peak value decreased, and the distance between peak point and coal wall and the influence region increased. The results of the study would have some guiding role in extra-thickness fully mechanized mining’s safety and efficiency.

scholarly journals Deformation Rules for Surrounding Rock in Directional Weakening of End Roofs of Thin Bedrocks and Ultrathick Seams

2020 ◽  
Vol 2020 ◽  
pp. 1-12
Author(s):  
Fei Liu ◽  
Zhanguo Ma ◽  
Yongsheng Han ◽  
Zhimin Huang
Keyword(s):  
Abutment Pressure ◽  
Main Roof ◽  
Stability Control ◽  
Surrounding Rock ◽  
Western China ◽  
Resource Exploitation ◽  
Failure Characteristics ◽  
Key Strata ◽  
Working Face ◽  
Geological Conditions

With the deployment of China’s energy strategy in the western regions, complex geological mining conditions such as thin bedrock and ultrathick seams in western China have caused a series of problems such as serious deformation of the surrounding rock at the ends of the working face and the increase in the lead abutment pressure of the roadways; the research on end roof deformation in the resource exploitation in western China has become one of the great demands of the industry. Based on the failure characteristics of rock mass, relying on the actual mining geological conditions of a coal mine in Inner Mongolia, the failure characteristics of the overlying rock strata under the influence of mining were simulated and analyzed using similar material simulation experiment, which intuitively reproduced the failure and deformation processes of the immediate roof, main roof, and key strata and revealed the mechanical mechanism of the directional weakening of the end roof. It is of great significance for the stability control of the surrounding rock at the end of the fully mechanized caving face in the thin bedrocks and ultrathick seams, reducing the abutment pressure of gate roadway and controlling the spontaneous combustion of residual coal in the goaf.

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.

scholarly journals Characteristics of the Roof Behaviors and Mine Pressure Manifestations During the Mining of Steep Coal Seam

2017 ◽  
Vol 62 (4) ◽  
pp. 871-891 ◽  
Author(s):  
Tu Hong-Sheng ◽  
Tu Shi-Hao ◽  
Zhang Cun ◽  
Zhang Lei ◽  
Zhang Xiao-Gang
Keyword(s):  
Coal Seam ◽  
Field Measurement ◽  
Main Roof ◽  
Mine Pressure ◽  
Steep Seam ◽  
Working Face ◽  
Geological Conditions ◽  
Depth Study ◽  
Dip Angle ◽  
Similar Simulation

Abstract A steep seam similar simulation system was developed based on the geological conditions of a steep coal seam in the Xintie Coal Mine. Basing on similar simulation, together with theoretical analysis and field measurement, an in-depth study was conducted to characterize the fracture and stability of the roof of steep working face and calculate the width of the region backfilled with gangue in the goaf. The results showed that, as mining progressed, the immediate roof of the steep face fell upon the goaf and backfilled its lower part due to gravity. As a result, the roof in the lower part had higher stability than the roof in the upper part of the working face. The deformation and fracture of main roof mainly occurred in the upper part of the working face; the fractured main roof then formed a “voussoir beam” structure in the strata’s dip direction, which was subjected to the slip- and deformation-induced instability. The stability analysis indicated that, when the dip angle increased, the rock masses had greater capacity to withstand slip-induced instability but smaller capacity to withstand deformation-induced instability. Finally, the field measurement of the forces exerted on the hydraulic supports proved the characteristics of the roof’s behaviors during the mining of a steep seam.

scholarly journals The Spatiotemporal Characteristics of Coupling Effect between Roof and Backfill Body in Dense Backfill Mining

Geofluids ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-15
Author(s):  
Xinyuan Zhao ◽  
Xinwang Li ◽  
Ke Yang ◽  
Zhen Wei
Keyword(s):  
Coupling Effect ◽  
Coal Pillar ◽  
Simulation Test ◽  
Spatiotemporal Characteristics ◽  
Coupling Behavior ◽  
Backfill Mining ◽  
Similar Simulation Test ◽  
Body Support ◽  
Observation Results ◽  
Similar Simulation

Backfill mining has become an important part of coal mine green mining technology. In this paper, the spatiotemporal characteristics of coupling effect between the roof and dense backfill body were analyzed by theoretical analysis and similar simulation test, and Xingtai Mine in China was taken as an engineering case for verification. The results show that the larger subsidence of the roof is, the stronger the supporting capacity of the backfill body is, and the interaction between the two is more obvious, thus showing a coupling effect. This coupling effect presents a regular variation with the increase of backfill distance and time, that is, the coupling degree of roof and backfill body is high in the middle of goaf and low in the vicinity of the coal pillar in spatial distribution, and the coupling behavior of roof and backfill body continues to occur slowly with time. Through the monitoring of stress and displacement in the engineering site and the analysis of borehole observation results, the spatiotemporal coupling effect between roof subsidence and backfill support is fully verified. The research results are of great significance to the control of surrounding rock in backfill mining, the study of the mechanical aging characteristics of backfilling materials, and the optimization of backfill body support performance.

scholarly journals Analysis on Subsidence Law of Bedrock and Ultrathick Loose Layer Caused by Coal Mining

Geofluids ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
Weiping Shi ◽  
Kaixin Li ◽  
Shengwen Yu ◽  
Cunzhi Zhang ◽  
Jingkai Li
Keyword(s):  
Coal Mining ◽  
Ground Subsidence ◽  
Simulation Test ◽  
Working Face ◽  
Similar Materials ◽  
Bedrock Surface ◽  
The Law ◽  
Similar Simulation Test ◽  
Theory Calculation ◽  
Loose Layer

In the process of coal mining, when the buried depth is large and the loose layer is thick, the ground subsidence tends to be abnormal, thus causing great damage to the surface ecological environment. In order to reveal the mechanism of mining ground subsidence under ultrathick loose layer, taking 1305 working face of a mine as the background, the law of mining ground subsidence under ultrathick loose layer was analyzed through field measurement. The law of bedrock subsidence is analyzed by similar simulation test, and the role of ultrathick loose layer in bedrock subsidence is quantitatively analyzed. The hydrophobic settlement model of ultrathick loose layer is established by settlement theory calculation, and the law of ground subsidence caused by hydrophobic of ultrathick loose layer is analyzed. The results show that the ground subsidence is mainly composed of bedrock subsidence and hydrophobic settlement of ultrathick loose layer. The maximum ground subsidence measured in the field is 4.201 m, the bedrock surface subsidence obtained by the simulation test of similar materials is 3.552 m, and the subsidence of ultrathick loose layer obtained by hydrophobic settlement analysis is 0.58 m. Adding the subsidence of bedrock surface and the subsidence of ultrathick loose layer, the ground subsidence is 4.132 m. It is in good agreement with the total ground subsidence measured in the field, which verifies the rationality that the ground subsidence mainly includes bedrock subsidence and hydrophobic settlement of ultrathick loose layer.

ASSESSMENT OF MAIN ROOF CA VING INCREMENTS IN WORKING FACE PROCESSING OF TOLMACHEVSKY COAL LAYER WITHIN THE DIP-WORKING PANEL 18-2

2019 ◽  
Vol 4 (1) ◽  
pp. 157-166
Author(s):  
V.O. Torro ◽  
◽  
A.V. Remezov ◽  
E.V. Kuznetsov ◽  
V.V. Klimov ◽  
...  
Keyword(s):  
Coal Mine ◽  
Face Processing ◽  
Main Parameter ◽  
Abutment Pressure ◽  
Main Roof ◽  
Roof Caving ◽  
Coal Layer ◽  
Working Face ◽  
Mine Tunnels

This work reviews the study aimed to assess the actual increments of the main roof caving which appear in the course of working face processing of ‘Tolmachevsky ' coal layer in ‘Polysayevskaya' coal mine as the main parameter defining the degree of abutment pressure influence on mine tunnels adjacent to working face.

scholarly journals Stress and deformation analysis of gob-side pre-backfill driving procedure of longwall mining: a case study

2021 ◽  
Author(s):  
Rui Wu ◽  
Penghui Zhang ◽  
Pinnaduwa H. S. W. Kulatilake ◽  
Hao Luo ◽  
Qingyuan He
Keyword(s):  
Rock Mass ◽  
Stress Distribution ◽  
Coal Seam ◽  
Abutment Pressure ◽  
Longwall Mining ◽  
Vertical Stress ◽  
Floor Level ◽  
Working Face ◽  
Floor Heave ◽  
Stress And Deformation

AbstractAt present, non-pillar entry protection in longwall mining is mainly achieved through either the gob-side entry retaining (GER) procedure or the gob-side entry driving (GED) procedure. The GER procedure leads to difficulties in maintaining the roadway in mining both the previous and current panels. A narrow coal pillar about 5–7 m must be left in the GED procedure; therefore, it causes permanent loss of some coal. The gob-side pre-backfill driving (GPD) procedure effectively removes the wasting of coal resources that exists in the GED procedure and finds an alternative way to handle the roadway maintenance problem that exists in the GER procedure. The FLAC3D software was used to numerically investigate the stress and deformation distributions and failure of the rock mass surrounding the previous and current panel roadways during each stage of the GPD procedure which requires "twice excavation and mining". The results show that the stress distribution is slightly asymmetric around the previous panel roadway after the “primary excavation”. The stronger and stiffer backfill compared to the coal turned out to be the main bearing body of the previous panel roadway during the "primary mining". The highest vertical stresses of 32.6 and 23.1 MPa, compared to the in-situ stress of 10.5 MPa, appeared in the backfill wall and coal seam, respectively. After the "primary mining", the peak vertical stress under the coal seam at the floor level was slightly higher (18.1 MPa) than that under the backfill (17.8 MPa). After the "secondary excavation", the peak vertical stress under the coal seam at the floor level was slightly lower (18.7 MPa) than that under the backfill (19.8 MPa); the maximum floor heave and maximum roof sag of the current panel roadway were 252.9 and 322.1 mm, respectively. During the "secondary mining", the stress distribution in the rock mass surrounding the current panel roadway was mainly affected by the superposition of the front abutment pressure from the current panel and the side abutment pressure from the previous panel. The floor heave of the current panel roadway reached a maximum of 321.8 mm at 5 m ahead of the working face; the roof sag increased to 828.4 mm at the working face. The peak abutment pressure appeared alternately in the backfill and the coal seam during the whole procedure of "twice excavation and mining" of the GPD procedure. The backfill provided strong bearing capacity during all stages of the GPD procedure and exhibited reliable support for the roadway. The results provide scientific insight for engineering practice of the GPD procedure.

Sign in / Sign up

Export Citation Format

Share Document