Research on Prediction Model of Mining Subsidence in Thick Unconsolidated Layer Mining Area

Shenshen Chi,Xuexiang Yu,Lei Wang,Xinjian Fang,Chuang Jiang

doi:10.1109/access.2021.3056873

Abstract

Accurately forecasting the scope of coal mining subsidence area is of great significance to the protection of surface structures. Due to the peculiarities of the unconsolidated layers rock formation, the surface movement of the thick unconsolidated layers mining area converges slowly at the boundary of the basin, and the boundary of the subsidence basin is larger than under conventional conditions. It is found that the existing models have a poor prediction effect at the boundary, and the predicted subsidence basin range is smaller than the actual basin range. To solve this problem, a new surface deformation prediction model based on Boltzmann function (IB) is proposed in this paper. Aiming at the problem that the model function is highly nonlinear and difficult to obtain parameters, the multi-population genetic algorithm (MPGA) is introduced into the parameter solution of the prediction model, and the parameter calculation model based on multi-population genetic algorithm (MPGAIB) is constructed. The simulation experiment and engineering example analysis show that both the overall fitting effect and the fitting effect at the boundary of IB model are closer to the actual situation, The MPGAIB model has good ability to anti-random error and gross error, and the result is stable.

Highlights

Surface deformation caused by underground mining is a global problem, which will cause damage to surface buildings, railways, rivers, etc., which seriously threatens the normal production and life of the residents in the mining area [1]–[5]
Compared with the conventional mining conditions, the mining subsidence mechanism and time-space law of thick unconsolidated layers are quite different, for example, the maximum surface subsidence value is greater than the coal seam thickness, the surface movement range is large, and the surface subsidence is intense during the mining period [8], [9]
2) MPGAIB This paper introduces the multi-population genetic algorithm into the process of IB model parameter calculation

Summary

INTRODUCTION

Surface deformation caused by underground mining is a global problem, which will cause damage to surface buildings, railways, rivers, etc., which seriously threatens the normal production and life of the residents in the mining area [1]–[5]. In response to the above problem, the author proposed a new prediction model of surface deformation based on the Boltzmann function, and derives the prediction formulas for the main section of the strike, the main section of inclination and any point on the surface. According to the principle of superposition, it can be understood as the difference between two SIE, and the calculation formula of the deformation of the main section along the strike can be obtained as follows: w0. It is assumed that the coal seam has reached full mining along the strike direction, and is not fully exploited along the inclination This situation is called finite extraction along dip (FEAD) (as shown in Fig.). In the IB model, the subsidence factor, the propagation angle of extraction, the offset of inflection point, and the horizontal movement coefficient have the same meaning as defined by the PIM. There are 10 parameters in the new model: q, P, b, θ0, s1, s2, s3, s4, tanβ, tanβ

IB PARAMETER CALCULATION

ANTI-GROSS ERROR ABILITY OF MPGAIB

ENGINEERING EXAMPLE

RELATIONSHIP BETWEEN IB PREDICTION PARAMETERS AND PIM PREDICTION PARAMETERS

Findings

CONCLUSION