A Fractal and Numerical Simulation Coupled Study of Fracture Network during Coal Mining Excavation

Yanan Gao,Feng Gao,Man-Chu Ronald Yeung

doi:10.1155/2014/158194

Abstract

This paper features a numerical study that is carried out by using discontinuous deformation method (DDA) and fractal geometry. The configurations of rock strata calculated by DDA were imported into a code that is written by using VC++ called “Fractal” to calculate the fractal dimension of the rock strata. As illustrated, a long wall mining case in China was presented. The relationship of the fractal dimension, excavation length, stress, and movement of strata were discussed. The evolution of fractal dimension can be considered as an index of instability or failure. The method proposed in this paper can be employed to predict the period weighting in long wall mining engineering.

Highlights

Numerical methods which are rapidly developing and have been widely employed in various engineering fields like geotechnical engineering, mining engineering, civil engineering, and so forth from the past decades [1, 2] can be used to study different geometry and time scales of engineering cases or lab tests and the results obtained by these methods can be repeated with ease
The evolution of fracture network can be simulated by using discontinuous method, such as UDEC [3] software and discontinuous deformation method (DDA) [4, 5]
Afterwards, the subsidence of the key stratum increased sharply and reached the maximum value when excavation was about 150 m. This means that the compaction degree of the rock mass under the key stratum increases before 150 m excavation

Summary

Introduction

Numerical methods which are rapidly developing and have been widely employed in various engineering fields like geotechnical engineering, mining engineering, civil engineering, and so forth from the past decades [1, 2] can be used to study different geometry and time scales of engineering cases or lab tests and the results obtained by these methods can be repeated with ease. Wang et al [6] set up a physical model to investigate the fracture network evolution of overburden rock mass. They pointed out in their study that there exists a strong relation between the ground pressure and evolution and configuration of the fracture network. Fractal dimension was employed as an index to study the evolution fracture network. Compared to lab tests, which are used to study material properties, the relative larger scale problem such as overburden rock movement is rarely studied except the work of Wang et al [6]. Inspired by the previous study, we attempt to explore more information based on numerical results and fractal dimension

Methodology and Basic Theory

Case Study

Conclusions