煤体裂隙非均质分布对注浆渗透扩散规律的影响分析

Numerical simulation of influence of coal pillar crack heterogeneity distribution on grouting permeability and diffusion law

注浆改性加固技术是改进裂隙煤岩稳定性的一种有效方式,探究并查明裂隙煤体浆液渗透扩散规律对于优化设计注浆参数具有重要意义。传统注浆渗透扩散模型未考虑煤体中裂隙非均质分布的影响,导致前期模拟计算结果与现场实际取得数据有较大误差。基于山西经坊煤业3-边角091运输大巷巷道迎采送掘工程,提出了基于数字照相与数字图像处理技术的煤体裂隙率识别方法,建立了基于Weibull分布的裂隙非均质性表征模型,利用多物理场耦合软件COMSOL建立了裂隙非均质分布的浆液渗透扩散数值计算模型,研究了平均裂隙率、裂隙分布均质性指数等参数对浆液扩散距离、浆液压力分布的影响规律,结果表明:平均裂隙率越高、裂隙分布均质性指数越大时,浆液压力越大,浆液渗透扩散速率越快,但当裂隙分布均质性指数达到一定程度后,模型中裂隙率分布趋近均匀,对浆液渗透扩散距离影响较小。与传统均质性模型相比,非均质模型的预测浆液渗透扩散距离减小了16.9%,与实际工程中不均匀渗透扩散规律相符,对于指导裂隙煤体注浆设计具有一定的参考意义。

Grouting modification and reinforcement technology is an effective way to control the stability of fractured coal surrounding rock. Accurate prediction of infiltration and diffusion law of grouting slurry in fractured coal is of great significance for scientific evaluation of grouting effect. The influence of heterogeneous distribution of fractures in coal is not taken into account in the traditional grouting seepage diffusion model, which results in a large error between the prediction results and the monitoring data. Based on the coal mining and excavation project of No.3-Biangle 091 tunnel in Jingfang Coal Industry of Shanxie, the identification method of coal seam rate based on digital photography and digital image processing technology was proposed, and the heterogeneity characterization model of coal seam based on Weibull distribution was established. A numerical calculation model of grouting grout permeability and diffusion was established using multi-physical field coupling software COMSOL, which considered the heterogeneity distribution of coal fissures. The influence of coal average fracture rate, fracture distribution homogeneity index and other parameters on grout diffusion distance and grouting pressure distribution in coal was studied. The results show that: when the average fracture rate is higher and the fracture distribution homogeneity index is higher, the grout pressure is higher and the permeability and diffusion rate of grout is faster. However, when the fracture distribution homogeneity index reaches a certain degree, the fracture rate distribution in the model tends to be uniform and has little influence on the permeability and diffusion results of grout. Compared with the traditional homogeneous model, the permeability and diffusion distance predicted by the heterogeneous model in is reduced by 16.9%, which is consistent with the law of uneven permeability and diffusion of grout in practical engineering, and has a certain theoretical significance for guiding the grouting design of fractured coal.