沿空切顶巷道围岩结构稳态分析及恒压让位协调控制

Steady analysis of gob-side entry retaining formed by roof fracturing and control techniques by optimizing mine pressure

基于无煤柱切顶成巷力学机理,分析了沿空切顶巷道围岩结构演化过程和力学作用机制,建立了工作面超前区、成巷段动压区和成巷段稳压区的全过程力学模型。根据不同分区动压显现特征,提出进行空间补偿,构建自成巷围岩稳态体系的巷道控制思路。从技术工艺优化和支护结构改造两方面着手,以空区碎胀矸体为稳态承载体,以恒阻变形主动支护结构、滑移让位挡矸支护结构和恒压可缩临时支护设备为巷内让压支护体,将应力集中部位转移至采空区,实现让压过程中可控让位。以厚煤层工作面无煤柱自成巷开采为工程背景,提出了稳定性成巷控制方案。结果表明,人为构建巷道围岩稳态体系是实现厚煤层切顶成巷围岩协调控制的有效途径之一。留巷前期以顶板压力上升为主,留巷后期以恒压让位为主。配套支护结构的力学特性满足护巷要求,不仅设备损坏率低且巷道变形人为可控,所留巷道各项指标满足下一工作面使用要求。

Based on the mechanism of the gob-side entry retaining formed by roof fracturing,the evolutionary laws of roof structures were theoretically studied during the entire entry retaining process.Accordingly,the retained entry was divided into the advanced pressure region in front of the mining panel,the dynamic and stable pressure regions behind the mining panel.According to the dynamic behaviors of the roof strata,an innovative entry control approach by artificially building a stable surrounding rock structure has been proposed in the study.In this approach,the bulking gangues were designed as bearing bodies at the gob area.The constant resistance and large deformation anchor cables,gangue prevention structures and pier-beam unit supports were designed as entry-in support bodies.Finally,the approach was tested at a thick coal seam longwall mining panel.Field monitoring showed that the stress concentration area was transferred to the gob area and the load-bearing capacity of the gangues was fully utilized after adopting the approach.The support pressure first increased and then maintained constant to build the stable surrounding rock structure.The indexes of the retained entry could meet the requirements of next panel.This study provides an effective approach for entry control in non-pillar longwall mining.