| With the coal resource mining depth and mining intensity going up,relevant problems become increasingly sharp,including severe deformation and destruction of roadway surrounding rocks under the impact of mining-induced stress and difficulty in roadway support,making the stable control of roadway surrounding rocks a major challenge in coal mining.In this regard,this paper,taking the uphill in Taoyuan Coal Mine Ⅱ2 mining area as the engineering background,probed into the distribution law of stope floor stress,the deformation and destruction features of uphill in the mining area as well as surrounding rock controlling technologies by combining such research methods as theoretical analysis,numerical simulation and engineering on-site measurement.The research results were all applied in engineering practice.Detailed research results are as follows:(1)A mechanical model of stope floor stress distribution under the impact of mining-induced stress has been established,an expression of the distribution of stope floor stress has been derived based on the theory of elasticity and the influence mining-induced stress exerted on the stress state of roadway surrounding rocks has been analyzed.An elastoplastic mechanical model of the roadway under the influence of mining-induced stress was established based on the stress state of roadway surrounding rocks.Considering the non-linear softening characteristics and capacity expansion characteristics of the surrounding rock,the analytical expression of the stress,displacement and range of plastic zone of roadway surrounding rocks under the influence of mining-induced stress have been derived based on the Mohr-Coulomb criterion,and sensitivity analysis of the factors affecting the deformation and destruction of the roadway has been conducted.(2)A numerical calculation model for the deformation and destruction features of the uphill in the mining area under the influence of mining-induced stress was established;the impact different working faces have on the deformation and destruction of the uphill surrounding rock in the mining area as well as the evolution law of surrounding rock stress field,displacement field and destruction field of surrounding rock under different horizontal and vertical distances between overlying working face and the roadway was analyzed,which provided theoretical basis for proposing means of supporting surrounding rock of the roadway under the influence of mining stress.(3)Numerical calculation models under different support solutions were established according to the deformation and destruction features of roadway surrounding rocks under the influence of mining-induced stress;the evolution law of the stress field of surrounding rock of the roadway,displacement field and plastic zone under different support solutions was analyzed,and roadway surrounding rocks control technology based on "anchor mesh and shotcrete + grouting bolt" was proposed;a numerical calculation model to observe the seepage and diffusion law of anchor grouting liquid was established to obtain reasonable grouting pressure,duration and grouting bolt spacing.(4)The proposed surrounding rock control technology has been applied in the uphill support project of Taoyuan Coal Mine Ⅱ2 mining area to measure the surface displacement of the roadway dynamically.According to the results,application of "anchor mesh and shotcrete + grouting bolt" support solution could effectively control the deformation level and rate and ensure long-term stability of roadway surrounding rocks.This paper has 64 figures,9 tables and 107 references. |
