Subsidence rules of underground coal mines for different soil layer thickness: Lu’an Coal Base as an example, China

Haifeng Hu,Xugang Lian

doi:10.1007/s40789-015-0088-8

Haifeng Hu, Xugang Lian

Open Access

https://doi.org/10.1007/s40789-015-0088-8

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Abstract

Damage caused by underground coal mining is a serious problem in mining areas in China; therefore, studying and obtaining the rules of ground movement and deformation under different geological conditions is of great importance. The numerical software ANSYS was used in this study to simulate mining processes under two special geological conditions: (1) thick unconsolidated soil layer and thin bedrock; (2) thin soil layer and thick bedrock. The rules for ground movement and deformation for different soil layer to bedrock ratios were obtained. On the basis of these rules, a prediction parameter modified model of the influence function was proposed, which is suitable for different values of unconsolidated soil layer thickness. The prediction results were verified using two sets of typical field data.

Highlights

Underground coal mining causes deformation and movement of strata and ground surface
Damage caused by underground coal mining is a serious problem in mining areas in China; studying and obtaining the rules of ground movement and deformation under different geological conditions is of great importance
The numerical software ANSYS was used in this study to simulate mining processes under two special geological conditions: (1) thick unconsolidated soil layer and thin bedrock; (2) thin soil layer and thick bedrock

Summary

Introduction

Underground coal mining causes deformation and movement of strata and ground surface. Based on the conditions of the Huainan coal mining area in China, by combining physical simulation, theoretical analysis and experimental data, the subsidence mechanism induced by underground mining of thick unconsolidated soil layer was studied, and a prediction model for this condition was established (Zhou et al 2014). Previous studies have dealt with the general rules of ground movement for different strata conditions based on simulation software and analysis of field data, which obviously addresses the influence of bedrock and the unconsolidated layer. Previous research did not directly transfer the rules of mining under unconsolidated layer and bedrock to the classic influence function of mining subsidence prediction, and the research results cannot be used to predict the value of surface movement and deformation.

Thick soil layer and thin bedrock

Thin soil and thick bedrock

Simulation of different thicknesses of unconsolidated soil layer

Simulation of different bedrock thicknesses

Findings

Case study