超深保护层开采巷道围岩控制技术研究

华丰煤矿1300 m超深保护层回采巷道稳定性控制是影响矿井安全高效生产的关键问题。基于现场地质力学综合测试、围岩非均匀性破坏机理研究,提出了超高强热处理预应力锚杆-锚注联合支护方案。研发了700 MPa级超高强热处理锚杆,其破断强度达850 MPa,冲击吸收功达100 J,并首次在1300 m埋深煤矿巷道进行了工业性试验。开展了巷道锚杆支护力、顶板四点离层与围岩钻孔应力等多参量变化在线监测,分析得出:超深巷道在爆破开挖扰动下,距离掘进工作面80 m后围岩整体变形基本稳定,但围岩深部应力仍然长期蠕变且呈现大幅值增降循环规律。试验结果表明,相比较于同巷顶板全锚索支护方式,锚杆?锚注联合支护下回采超前段巷道变形量整体降低了50%,掘进支护效率提高了20%。

Study on surrounding rock control technology for mining roadway in ultra-deep protective layer

The stability control of the mining roadway in the 1300 m ultra-deep protective layer of Huafeng Colliery is a bottleneck prob?lem affecting the safe and efficient production of the mine.Based on the comprehensive testing of on-site geomechanics and the study of the specific failure mechanism of surrounding rock,a combined support plan of ultra-high-strength heat-treated pre-stressed bolt with cablegrouting is proposed.The 700 MPa grade ultra-high-strength heat-treated bolt was developed with reaking strength of 850 MPa and an im?pact absorption power of 100 J;underground industrial test was firstly carried out in the 1300 m deep coal mine roadway.The monitoring of multi-parameter changes such as roadway bolt support force,four-point roof separation and surrounding rock borehole stress was carried out on site,and the analysis obtained:under the disturbance of blasting excavation,the overall surrounding rock deformation is basically stable after a distance of 80 m from the front of the ultra-deep roadway;however,the deep stress of the surrounding rock still creeps for a long time and exhibits a large-scale increase and decrease cycle.The test results show that:compared with the roof full-anchor cable sup?port method,the overall deformation of the roadway in the super front section is reduced by 50%,and the excavation support efficiency is increased by 20%.