A Method of Backfill Mining Crossing the Interchange Bridge and Application of a Ground Subsidence Prediction Model

Shuaigang Liu,Jianbiao Bai,Bowen Wu,Gongyuan Wang,Xiangyu Wang

doi:10.3390/min11090945

Abstract

The traditional backfill mining method is a technology developed by the general trend of green coal mining, but with a high cost and an impact on production efficiency. This paper proposes a structured backfill mining method with high-water materials and pillars. The evolution of roof pressure appearance is assessed through the sensor and monitoring system in the hydraulic support. The main roof fracture step distance is determined based on the roof structure characteristics of backfill mining, and the backfill step distance of underground structural backfill is 22.7 m considering the safety factor. Through the simulation results of Abaqus commercial simulation software, the roof subsidence evolution of different backfill schemes under temporary load and permanent load is compared, and the rationality of the backfill step distance is verified. Based on the probability integral method, the surface subsidence prediction model is proposed, then the final value and the maximum dynamic change value of the surface subsidence at the north and south ends of the interchange bridge by traditional mining and backfill mining are analyzed, which verifies the rationality of the structural backfill mining method.

Highlights

Ground subsidence mitigation regarding backfill mining is inextricably linked to backfill mining technology [1,2,3,4,5]
Through field measurement, theoretical analysis, and numerical simulation, a structural backfill method based on roof structural characteristics is proposed
The main conclusions obtained are as follows: (1) Based on the monitoring result of the hydraulic support resistance, the periodic weighting step is determined to be an average of 17 m, the main roof load is calculated to be to be 0.493 MPa, and the backfill step distance is determined to be 22.7 m

Summary

Introduction

Ground subsidence mitigation regarding backfill mining is inextricably linked to backfill mining technology [1,2,3,4,5]. Towards the extent that solid backfill can be used to control ground subsidence, some scholars have conducted systematic analyses of the equivalent mining diameter theory of strata movement in backfill mining, developed a structural mechanics model of strata movement in high-density backfill mining, and performed continuous medium mechanics analysis [6,7,8]. Some scholars established a model for estimating solid-filled coal mining subsidence based on the equivalent mining height theory, suggested a design procedure for solid-filled mining under buildings, as well as described a strategy for determining the probability integral method’s parameters [11,12,13]. Li et al [16] developed a method for calculating subsidence regions using a surface subsidence database and described the principles, specifications, methodologies, and steps for sketching a subsidence boundary, completed a quantitative assessment of underground coal mining damage caused by surface subsidence and promoted the use of Geographic Information

Objectives

Methods

Findings

Conclusion