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为进一步完善基于FLAC~(3D)的可破断锚杆单元,分析了以任意单元极限伸长量为破断判据的原可破断锚杆单元存在的缺陷;提出了基于锚杆自由段总体伸长量的锚杆破断判据,修正了原可破断锚杆单元;开展了锚杆杆体拉伸试验,结果表明修正后的可破断锚杆单元更加符合实际。以深部煤矿实际工程为背景,进行了数值模拟对比分析,结果表明:自带cable单元不具有破断属性,将会使支护设计偏于危险;原可破断锚杆单元方案中锚杆过早地全部发生破断,实际锚固效果被抑制;修正后的可破断锚杆单元能准确反映实际锚固效果,与工程实际更吻合。进一步开展了锚固参数正交试验,结果显示锚杆破断率随间排距增大而显著增大,随锚固长度和预紧力的增加先增加后减小,受预紧力影响相对最不显著;基于此提出了深部煤巷锚固参数优化原则,并得到现场验证。
In order to further improve the breakable anchor rod unit based on FLAC 3D, the defects of the original breakable anchor rod unit with the unit ultimate elongation as the breaking criterion are analyzed. Based on the analysis of the total elongation The bolt breakage criterion was modified and the original breakable anchor rod unit was modified. The tensile test of anchor rod body was carried out. The results show that the modified breakable anchor rod unit is more realistic. Based on the actual engineering of deep coal mine, the numerical simulation is carried out. The results show that the self-contained cable unit does not have the breaking property, which will make the design of support more dangerous. All of them broke, and the actual anchoring effect was restrained. The modified breakable anchor rod unit can accurately reflect the actual anchoring effect, which is more consistent with the actual project. The orthogonal test of anchorage parameters was further carried out. The results showed that the breaking rate of anchor rod increased significantly with the increase of row spacing, and then increased with the increase of anchorage length and pretension force, then decreased with the prestressing force being the least significant Based on this, the optimization principle of anchoring parameters in deep coal roadway is proposed and verified by on-site verification.