scholarly journals Sensitivity Analysis and Numerical Simulation Study on Main Controlling Factors of Surface Movement and Deformation in Strip Filling Mining under Thick Unconsolidated Layers

Geofluids ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-10
Author(s):  
Dequan Sun ◽  
Quanlin Wu ◽  
Xiaoyan Li ◽  
Zhaomin Zhang ◽  
Xiaotian Xu ◽  
...  
Keyword(s):  
Layer Thickness ◽  
Influence Factors ◽  
Surface Subsidence ◽  
Control Technology ◽  
Filling Rate ◽  
Surface Movement ◽  
Deformation Parameters ◽  
Body Strength ◽  
Movement And Deformation ◽  
Coal Pillars

In many mining areas, there is a lot of pressed coal under buildings, railways, and water bodies, and there are geological conditions of thick unconsolidated layers, so the surface subsidence has certain particularity. The key to solve the problem of pressed coal is the control technology of surface subsidence. The development of strip filling technology provides a kind of economical and effective surface subsidence control technology. With the passage of time, the natural weathering, flow, and fracture of some coal pillars may lead to the instability and failure of some coal pillars. Therefore, the selection of filling parameters plays an important role in the stability of coal pillars. In order to study the influence factors of surface movement and deformation, considering the influence factors of filling rate, key layer thickness, filling body strength, and unconsolidated layer thickness, FLAC 3D was used to simulate the surface movement deformation, and the orthogonal test method was used to analyze the simulation results, and the sensitivity of the main control factors affecting the surface deformation affected by strip filling mining was studied. The results show that the order of importance of the four factors on the four surface movement and deformation parameters is filling rate > key layer thickness > filling body strength > unconsolidated layer thickness. The influence of these four factors on the surface movement and deformation parameters is gradually decreasing, but the influence degree of different factors has drawn a certain gradient.

Study on Surface Movement and Deformation by Mining in Loess Gully Region

2013 ◽  
Vol 295-298 ◽  
pp. 3005-3009
Author(s):  
Bing Chao Zhao ◽  
Xue Yi Yu ◽  
Jin Dong Wang
Keyword(s):  
Risk Assessment ◽  
Prediction Model ◽  
Theory Model ◽  
Surface Subsidence ◽  
Level Surface ◽  
Surface Movement ◽  
Movement And Deformation ◽  
Analysis Prediction

Aims at the problem on surface subsidence calamity in loess gully region , applies on the best result of surface subsidence disaster by mining, basis on analysis prediction model of level surface and character of surface movement and deformation in gully region, and combines the character of landslide and slip accompanies hilly surface movement and deformation by mining, and establishes theory model of surface movement and deformation and determine model of the landslide may occur, it is further verified correctness and rationality by project, and It has some significance on hilly surface movement and deformation and protect the object of risk assessment.

Mechanism of Abnormal Surface Subsidence Induced by Fault Instability

2020 ◽  
Author(s):  
Gangyan Zhang
Keyword(s):  
Rock Mass ◽  
Fault Zone ◽  
Hanging Wall ◽  
Friction Angle ◽  
Soil Mass ◽  
Surface Subsidence ◽  
Surface Movement ◽  
Fault Stability ◽  
Movement And Deformation ◽  
Dip Angle

Abstract Surface movement and deformation with faults differ significantly from that without faults, which the surface movement and deformation at the fault outcrop generally abnormally increase when a fault occurs in the overlying strata and loses stability as a result of mining. To explore the mechanism of abnormal surface subsidence induced by fault instability due to mining in the hanging wall and footwall, mechanical models for the fault slip and soil cantilevers were separately established. Moreover, based on numerical and similarity simulation experiment, the difficulty degrees of fault instability were compared and analysed during mining in hanging wall and footwall. The research results show that: (1) the abnormal surface subsidence at fault outcrop is caused by fracture of soil mass at the fault outcrop due to the cantilever effect. (2) The fault zone that can be stabilised during mining in the hanging wall is broader than that during mining in the footwall, and a fault remains stable when mining in hanging wall and the surface at fault outcrop is more likely to experience stepped subsidence when mining in the footwall. (3) Fault stability worsens with the growth of the fault dip angle when mining in hanging wall, the fault is certainly subjected to slip and instability when fault dip angle is lower than the internal friction angle of the rock mass within the fault zone and fault stability strengthens with increasing fault dip angle during mining in the footwall. (4) When mining in the footwall, the ratio of shear stress to normal stress at the fault outcrop is about five times that when mining in the hanging wall and the fault is more likely to undergo slip and instability during mining in the footwall. (5) As a natural weak plane in the rock mass, a fault exerts a blocking effect on the transfer of mining-induced stress and overburden movements.

Control Effect of Alluvium and Bedrocks on Surface Subsidence

2014 ◽  
Vol 675-677 ◽  
pp. 1376-1380
Author(s):  
Xue Yi Yu ◽  
Qi Wang ◽  
Bing Chao Zhao ◽  
Wen Bin Guo ◽  
Jin Dong Wang
Keyword(s):  
Influence Factors ◽  
Ground Surface ◽  
Surface Subsidence ◽  
Ground Movement ◽  
Control Effect ◽  
Key Stratum ◽  
Working Face ◽  
Movement And Deformation ◽  
Cutting Height ◽  
Discrimination Method

Through analyzing the structure of the alluvium and bedrocks, a discrimination method of main influence factors of surface subsidence was proposed, and the discrimination formula was put forward. Taking the overburden and ground surface of the large cutting height working face in Bin Chang mining region as the research object, the structure and location of key stratum and the structure of the alluvium was analyzed. Besides, through the surface monitoring, the parameters of ground movement and deformation was given, and the discrimination method was verified to be correct. Furthermore, using numerical simulation, the alluvium and bedrocks influences on the surface subsidence under different mining width were studied respectively; the ground movement and deformation characteristics under the influence of alluvium and bedrocks were put forward. The study has provided a basis for the prediction of surface subsidence under certain conditions.

Analysis on Characteristics of Surface Subsidence with Han Jia Wan Coal Mine

2012 ◽  
Vol 524-527 ◽  
pp. 520-524 ◽  
Author(s):  
Xue Yi Yu ◽  
Peng Wang ◽  
Xing Liang Li
Keyword(s):  
Coal Mine ◽  
Scientific Basis ◽  
Surface Subsidence ◽  
Surface Cracks ◽  
Surface Movement ◽  
Working Face ◽  
Shallow Coal Seam ◽  
Movement And Deformation ◽  
Main Factors ◽  
Movement Parameters

Surface subsidence has some peculiarities for the mining of the Han jia wan coal mine. Based on the surface movement observation of 2304 working face in Han jia wan coal mine, mining strata movement parameters are analyzed, the main factors which influence the formation of surface cracks in the gob are proposed and the failure mechanism of surface movement and deformation are studied for the mining of shallow coal seam and thick loose bed. Correlative parameters are presented and scientific basis is established for the coal mining under buildings, rail and water and the leaving of the safety pillar in the future.

scholarly journals Experimental Analysis of the Influence of Factors Acting on the Layer Thickness Formed by Anodic Oxidation of Aluminium

Coatings ◽  
2019 ◽  
Vol 9 (1) ◽  
pp. 57 ◽  
Author(s):  
Miroslav Gombár ◽  
Alena Vagaská ◽  
Marta Harničárová ◽  
Jan Valíček ◽  
Milena Kušnerová ◽  
...  
Keyword(s):  
Surface Layer ◽  
Layer Thickness ◽  
Anodic Oxidation ◽  
Current Practice ◽  
Oxidation Process ◽  
Influence Factors ◽  
Basic Criterion ◽  
Electrolysis Method ◽  
Current Densities ◽  
Anodic Oxidation Process

The current practice in the field of anodic oxidation of aluminium and its alloys is based mainly on a set of partial empirical experiences of technologists obtained during surface treatment. The aim of the presented paper is deeper and more complex identification of the influence of chemical and technological factors acting during the anodic oxidation process especially on the thickness of the formed surface layer by the electrolysis method in a sulfuric acid solution. The current density was selected as the basic criterion for verification evaluation and analysis of experimentally obtained data, in accordance with Faraday’s laws. For current densities of 1 to 5 A·dm−2, the synergy of significant influence factors was identified, and mathematical and statistical models were then developed to predict the thickness of the surface layer with a relative accuracy of up to 10%. The presented paper does not only focus on the observation of the thickness of the surface layer desired by the customer, but also on the monitoring of this thickness in relation to the overall layer thickness of the coating.

scholarly journals Control Technology of Surface Movement Scope with Directional Hydraulic Fracturing Technology in Longwall Mining: A Case Study

Energies ◽  
2019 ◽  
Vol 12 (18) ◽  
pp. 3480 ◽  
Author(s):  
Zhanjie Feng ◽  
Wenbing Guo ◽  
Feiya Xu ◽  
Daming Yang ◽  
Weiqiang Yang
Keyword(s):  
Numerical Simulation ◽  
Hydraulic Fracturing ◽  
Longwall Mining ◽  
Numerical Models ◽  
Surface Subsidence ◽  
The Sustainable Development ◽  
Surface Movement ◽  
Directional Hydraulic Fracturing ◽  
Simulation Results ◽  
Overlying Strata

Mining-induced surface subsidence causes a series of environmental hazards and social problems, including farmland destruction, waterlogging and building damage in the subsidence area. To reduce mining damages, an innovative method of controlling the surface movement scope via artificial weak planes generated by hydraulic fracturing technology was proposed in this paper. Numerical models were built to analyze the influence of weak planes with different heights and dips on the overlying strata movement. The numerical simulation results showed that the weak planes structure cut off the development of the overlying strata displacement to the surface and affected the surface movement scope. When the weak planes’ dips were bigger than the angle of critical deformation, with the increase of the weak planes’ heights (0–120 m) the advance angle of influence changed from 53.61° to 59.15°, and the advance distance of influence changed from 173.31 m to 140.27 m which decreased by 30.04 m. In applications at Sihe coal mine in China, directional hydraulic fracturing technology was used in panel 5304 to form artificial weak planes in overlying strata. The measured surface subsidence and deformation value met the numerical simulation results and the mining-induced surface movement scope reduced. Moreover, no damage occurred to the surface buildings which were predicted to be in the affected area after extraction. This technology provided a new method to protect the surface structures from damages and had great benefits for the sustainable development of coal mines.

Numerical Simulation on the Surface Subsidence Effect during Shield Tunneling Construction

2011 ◽  
Vol 299-300 ◽  
pp. 110-113
Author(s):  
Hai Xia Sun ◽  
Hai Yu Wu ◽  
Si Li Chen
Keyword(s):  
Numerical Simulation ◽  
Finite Element ◽  
Surface Deformation ◽  
Influence Factors ◽  
Surface Subsidence ◽  
Shield Tunnel ◽  
Shield Tunneling ◽  
Finite Element Program ◽  
Element Program ◽  
Numerical Simulation Methods

Against the background of shenyang subway shield tunnel construction, the method of numerical simulation methods are used to analyze the factors of surface subsidence caused by shield construction comprehensively, and the universal finite element program ABAQUS is used to establish mechanical model depended on comprehensive consideration the influence factors of soil warehouses pressure, seepage and groundwater. A dynamic finite element simulation of shield advance process and conclude the surface deformation rule of soil are studied.

INFLUENCE OF DEPOSITION AND FOULING ON WALL TEMPERATURE DISTRIBUTION IN CONVECTIVE PATH

2020 ◽  
pp. 1-21
Author(s):  
Deli Li ◽  
Enlu Wang ◽  
Jinda Mao ◽  
Wei Wu ◽  
Yiyang Wang
Keyword(s):  
Temperature Distribution ◽  
Surface Temperature ◽  
Temperature Control ◽  
Theoretical Calculations ◽  
Influence Factors ◽  
Control Technology ◽  
Tube Surface ◽  
Gas Temperature ◽  
Surface Distribution ◽  
Super Heater

Abstract To develop a method of controlling the deposit tube surface temperature, the rules of deposition and fouling on the fireside, and the influence factors of the surface distribution were determined through experiments and theoretical calculations. The surface temperature distribution of a clean tube was compared with that of a deposit tube. Through theoretical calculations, the influence factors of the deposit tube surface temperature were evaluated. Based on the investigation, surface temperature control technology applicable to a super-heater was proposed and the feasibility of this heater was determined. A bimodal distribution was obtained when the temperature distribution of the deposit tube was plotted as a function of the angle, whereas a unimodal distribution was obtained for the clean tube. The results revealed that the heat exchange tube surface temperature is most effectively controlled by controlling the flue gas temperature. Prior to the development of higher performance materials (compared with conventional materials), surface temperature control technology can be used to ensure that the super-heater surface temperature lies below the allowable temperature of existing super-heater materials.

Analysis and Control of Layer Deformation Induced by the Densely Arranged Large Diameter Underground Steel Tubes Jacking with NTR Method

2015 ◽  
Vol 744-746 ◽  
pp. 1010-1014
Author(s):  
Chun Fu Jin ◽  
Peng Niu ◽  
Yong Sheng Zhao ◽  
Xuan Wang
Keyword(s):  
Surface Deformation ◽  
Large Diameter ◽  
Influence Factors ◽  
Surface Subsidence ◽  
The Finite Element Method ◽  
Steel Tubes ◽  
Steel Pipes ◽  
Pipe Jacking ◽  
And Control ◽  
Layer Deformation

Combined with the finite element method (FEM) and the field data of Shenyang Metro NTR engineering for pipe jacking process, the variation of surface deformation and influence factors of NTR construction are systematically analyzed. The result is shown that the curves of the lateral surface subsidence produced by pipe jacking process are accord with the normal distribution curves put forward by Peck .When the top steel pipes are jacked , the surface subsidence develops rapidly and the rate of deformation is larger. In addition , grouting behind the wall and the sequence of the pipe jacking all have a greater impact on the deformation of the layer.

scholarly journals Failure Mechanism and Control Technology of Thick and Soft Coal Fully Mechanized Caving Roadway under Double Gobs in Close Coal Seams

2020 ◽  
Vol 2020 ◽  
pp. 1-23
Author(s):  
Shengrong Xie ◽  
Xiaoyu Wu ◽  
Dongdong Chen ◽  
Yaohui Sun ◽  
En Wang ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Coal Seam ◽  
Field Distribution ◽  
Control Technology ◽  
Coal Seams ◽  
Anchor Bolt ◽  
Anchor Cable ◽  
Coal Pillars ◽  
Seam Mining ◽  
And Control

The surrounding rock of the roadway under double gobs in the lower coal seams is partially damaged by the mining of the upper coal seam and the stress superimposition of the stepped coal pillars. What is worse, the upper layer of the roof is collapse gangue in double gobs, which makes the anchor cable unable to anchor the reliable bearing layer, so the anchoring performance is weakened. The actual drawing forces of the anchor bolt and anchor cable are only approximately 50 kN and 80 kN, respectively. The roadway develops cracks and large deformations with increasing difficulty in achieving safe ventilation. In view of the above problems, taking the close coal seam mining in the Zhengwen Coal Mine as the engineering background, a theoretical calculation is used to obtain the loading of the step coal pillars and the slip line field distribution of the floor depth. The numerical simulation monitors the stress superimposition of stepped coal pillars and the distribution of elastoplastic areas to effectively evaluate the layout of mining roadways. The numerical simulation also analyzes the effective prestress field distribution of the broken roof and grouting roof anchor cable. A laboratory test was used to monitor the strength of the grouting test block of the broken coal body. Then, we proposed that grouting anchor cable be used to strengthen the weak surface of the roof and block the roof cracks. From on-site measurement, the roadway was seen to be arranged in the lateral stress stabilization area of the stepped coal pillars, the combined support technology of the grouting anchor cable (bolt) + U type steel + a single prop was adopted, the roadway deformation was small, the gas influx was reduced, and the drawing force of the anchor bolt and the anchor cable was increased to approximately 160 kN and 350 kN, respectively. The overall design and control technology of the roadway can meet the site safety and efficient production requirements.

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