煤矿千米深井巷道围岩支护-改性-卸压协同控制技术

Roadway strata control technology by means of bolting-modificationdestressing in synergy in 1 000 m deep coal mines

  • 摘要: 针对煤矿千米深井、软岩、强采动巷道围岩大变形难题,以淮南新集口孜东矿350 m超长工作面运输巷为工程背景,分析了巷道围岩大变形、支护构件失效原因;采用理论分析、实验室试验和井下试验方法,从围岩物性劣化、偏应力诱导围岩扩容、软岩结构性流变及超长工作面采动影响等方面,揭示了高地应力与超长工作面强采动应力叠加作用下巷道围岩大变形机理。以此为基础提出千米深井、软岩、强采动巷道支护-改性-卸压协同控制理念,采用数值模拟对比研究了无支护、锚杆支护、锚杆支护-注浆改性、锚杆支护-注浆改性-水力压裂卸压4种方案巷道围岩应力、变形及破坏规律,阐述了巷道支护-改性-卸压协同控制原理。研发出CRMG700超高强度、高冲击韧性锚杆支护材料,研究揭示了锚杆受拉、剪、扭、弯及冲击复合载荷作用的力学响应特征;开发出微纳米无机有机复合改性材料及配套高压劈裂注浆技术;研发出分段压裂水力压裂卸压技术与设备,形成了巷道支护-改性-卸压协同控制技术。基于上述研究成果,提出口孜东矿示范巷道支护-改性-卸压布置方案与参数,并进行了井下试验与矿压监测。监测结果表明,巷道围岩协同控制技术应用后,巷道变形量降低50%以上,锚杆、锚索破断率降低90%,工作面采动应力明显减小,有效控制了千米深井、软岩、强采动巷道大变形。最后,对下一步的研究工作进行了展望。

     

    Abstract: In order to overcome the difficult problems associated with the roadway large deformation in the coal mines with 1 000 m buried depth,soft rock and intense mining induced affect,the causes of large rock deformation and bol- ting component damage were analyzed on the basis of a maingate in a working face with extra-long width located in the Kouzidong coal mine,the Xinji mining area,China. The rock large deformation mechanism under the superposition ac- tion of high in-situ stresses and intense mining induced stresses around the face with extra-long width was revealed from following aspects:rock property degradation,rock dilatancy caused by deviatoric stresses,structural rheology of soft rock,and mining induced affect,by means of theoretical analyses,laboratory tests and underground experiments. The synergy strata control idea with bolting-modification-destressing was put forward for the roadways with 1 000 m buried depth,soft rock and intense mining induced affect. The rock stresses,deformation and damage features around roadways unsupported,and controlled by rock bolting,bolting-grouting modification,and bolting-grouting modification- hydraulic fracture destressing,were studied through numerical simulation,and the synergy strata control principle is ex- pounded. The CRMG700 rock bolt rebar with extra-high strength and high impact toughness was developed,and the mechanical response features of the bolt under tension,shear,torsion,bending,impact load and various combination were revealed. The micro-nano inorganic and organic grouting composite materials and high pressure split grouting technique were developed. The hydraulic fracture destressing technique and facilities were developed,which form the roadway synergy control technology with bolting-modification-destressing. Based on the above-mentioned achievements, the rock control pattern and parameters were put forward with bolting-modification-destressing for the experimental en- try in the Kouzidong coal mine,and the field experiment and monitoring were conducted. The monitoring data demon- strated that the entry deformation was decreased by more than 50% ,the broken percentage of bolts and cables was re- duced by 90% ,and the mining induced stress was obviously mitigated after the rock synergy control technology was applied,which effectively contained the large deformation of roadway with 1 000 m buried depth,soft rock and intense mining induced affect.

     

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