Study on the Coefficient of Surface Subsidence by Mining on the Condition of Thick Unconsolidated Layers and Thin Stratum

2013 ◽  
Vol 448-453 ◽  
pp. 3873-3878
Author(s):  
Hong Tao Wang ◽  
Bing Chao Zhao ◽  
Jin Dong Wang
Keyword(s):  
Surface Subsidence ◽  
Theory Analysis ◽  
Simulation Test ◽  
Key Strata

Aim at the phenomenon of sidestep subsidence on surface by mining on the condition of thick unconsolidated layers and thin stratum,article bases on the theory analysis and calculation, and uses determining key strata and key strata flexibility calculation, and expatiates the characters of η, and makes it divide into subsection function. Contrast with project example and simulation test, it shows:if subsection function η is applied, then using it to forecast the quantity of surface subsidence that will be more approach to fact, which can syllabify explain phenomenon of sidestep subsidence on surface, and has definite meaning to coach locale.

scholarly journals Movement Laws of Overlying Strata above a Fully Mechanized Coal Mining Face Backfilled with Gangue: A Case Study in Jiulishan Coal Mine in Henan Province, China

2021 ◽  
Vol 2021 ◽  
pp. 1-20
Author(s):  
Zhengkai Yang ◽  
Zhiheng Cheng ◽  
Zhenhua Li ◽  
Chunyuan Li ◽  
Lei Wang ◽  
...  
Keyword(s):  
Coal Mining ◽  
Main Roof ◽  
Surrounding Rock ◽  
Surface Subsidence ◽  
Key Strata ◽  
Key Stratum ◽  
Mining Face ◽  
Failure Depth ◽  
Gangue Backfilling ◽  
Overlying Strata

The aim of this study is to obtain movement laws of overlying strata above a fully mechanized coal mining face backfilled with gangue and solve the problem of surface subsidence during coal mining. This study was carried out based on gangue backfilling mining of Jiulishan Coal Mine (Jiaozuo City, Henan Province, China) from the perspectives of deformation of backfilled gangue under compaction, surrounding rock of a stope, and activities of key strata. The method combining with rock mechanics, viscoelastic mechanics, control theory of rock mass under mining, and numerical simulation was used based on physical and mechanical characteristics of backfilled gangue. On this basis, the research analyzed the temporal-spatial relationships of activities of surrounding rock of the stope, compressive deformation of backfilling body, failure depth of the floor, deformation characteristics of the main roof with laws of surface subsidence. The movement characteristics of overlying strata above the fully mechanized coal mining face backfilled with gangue and the traditional fully mechanized mining face were compared. It is found that, under the same conditions of overlying strata, movement laws of overlying strata are mainly determined by the mining height of coal seams and the heights of a caving zone and a fracture zone are nearly linearly correlated with the mining height. Through analysis based on thin-plate theory and key stratum theory, the location of the main roof of the fully mechanized coal mining face backfilled with gangue in coal seams first bending and sinking due to load of overlying strata was ascertained. Then, it was determined that there are two key strata and the main roof belongs to the inferior key stratum. By using the established mechanical model for the main roof of the fully mechanized coal mining face backfilled with gangue and the calculation formula for the maximum deflection of the main roof, this research presented the conditions for breaking of the main roof. In addition, based on the theoretical analysis, it is concluded that the main roof of the fully mechanized coal mining face backfilled with gangue does not break, but bends. The numerical simulation results demonstrate that, with the continuous increase of strength of backfilled gangue, the stress concentration degree of surrounding rock reduces constantly, so does its decrease amplitude. Moreover, the compressive deformation of backfilling, failure depth of the floor, and bending and subsidence of the main roof continuously decrease and tend to be stable. The mechanical properties of backfilling materials determine effects of gangue backfilling in controlling surface subsidence. Gangue backfilling can effectively control movement of overlying strata and surface subsidence tends to be stable with the increase of elastic modulus of gangue.

scholarly journals Constitutive Model of Solid Backfill Materials and Numerical Simulation of Overburden Movement and Deformation in Backfill Mining

2021 ◽  
Vol 2021 ◽  
pp. 1-14
Author(s):  
Chao Ma ◽  
Lianying Zhang ◽  
Bing Li ◽  
Xianbiao Mao
Keyword(s):  
Constitutive Model ◽  
Surface Subsidence ◽  
Compaction Process ◽  
Compaction Rate ◽  
Key Strata ◽  
Mining Depth ◽  
Backfill Mining ◽  
Backfill Materials ◽  
Initial Compaction ◽  
Mining Height

Solid backfill mining is an efficient and environmental-friendly coal mining technology, which can effectively solve the problems of coal gangue pollution, water resource loss, and surface subsidence. Based on the mechanical behavior of backfill materials in the compaction process, volume strain was used to express the deformation modulus, and a constitutive model of backfill materials was proposed in this study. The ABAQUS UMAT was used to develop the numerical calculation subroutine of the model. Finally, the rationality of the model was verified that simulated stress-strain curves of the backfill materials during the compaction process agree well with experiments. Based on the proposed constitutive model, the influence of three factors (the initial compaction rate of the filling body, the mining height, and the mining depth) on the key strata and surface subsidence was analyzed systematically. The results show that the initial compaction rate and the height of coal seams have significant influences on surface subsidence. When the thickness of topsoil is only changed and the structural composition and lithology of overburden are not changed, the mining depth has little influence on surface subsidence, but a significant influence on surface subsidence range. The influence of mining height and mining depth on the deformation of key strata of overburden and surface subsidence is approximately linear, while the influence of the initial compaction rate is nonlinear.

scholarly journals Subsidence Prediction of Overburden Strata and Surface Based on the Voussoir Beam Structure Theory

2018 ◽  
Vol 2018 ◽  
pp. 1-13 ◽  
Author(s):  
Changchun He ◽  
Jialin Xu
Keyword(s):  
Inflection Point ◽  
Surface Subsidence ◽  
Structure Theory ◽  
Block Length ◽  
Beam Structure ◽  
Key Strata ◽  
Zone Width ◽  
Offset Distance ◽  
Overburden Strata ◽  
Subsidence Curve

The hard and stiff strata (key strata) bear the overburden load in the form of a voussoir beam structure (VBS) after break. The VBS affects both the surface subsidence and the stope underground pressure. Therefore, the reasonable method to predict the surface subsidence is based on the whole subsidence formulae of the VBS. This study first establishes the subsidence formulae of the VBS analytically. The influence of the block length on the subsidence curve and the VBS level on the zero-subsidence range are then analyzed based on the subsidence formulae of the VBS. The results show the half-subsidence curve of the VBS is an S-shaped curve. The block length hardly affects the S-shaped subsidence curve determined by the width of the undercompacted zone. Furthermore, a greater undercompacted zone width corresponds to a greater offset distance of the inflection point. The higher the VBS level, the farther the zero-subsidence range, and the flatter the subsidence curve. The subsidence of the highest VBS can approximately represent the surface subsidence when the topsoil is thin enough.

Kinematics Analysis of Virtual Prototype System on Multiple Redundant Bionic Arm

2014 ◽  
Vol 945-949 ◽  
pp. 1360-1363 ◽  
Author(s):  
Kai Zhao ◽  
Xiu Juan Liu ◽  
Li Min Song ◽  
Chun Guang Wang ◽  
Lei Yuan
Keyword(s):  
Theoretical Analysis ◽  
Virtual Machine ◽  
Future Development ◽  
Development Process ◽  
Simulation Software ◽  
Prototype System ◽  
Kinematics Analysis ◽  
Theory Analysis ◽  
Simulation Test ◽  
Simulation Results

The simulation technology can be very convenient for the kinematics analysis of the virtual machine system. It not only simplifies the development process of product design, but also verifies the correctness and feasibility of the theory. Based on the theory analysis, simulation test is finished with the simulation software, and the correctness of the theoretical analysis is validated. Through the analysis on the simulation results of the torque, reference for future development of prototype is provided.

The journey of an integrationist: A grounded theory analysis.

Psychotherapy ◽  
2016 ◽  
Vol 53 (1) ◽  
pp. 78-89 ◽  
Author(s):  
Tomas Rihacek ◽  
Ester Danelova
Keyword(s):  
Grounded Theory ◽  
Theory Analysis
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