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基于端锚锚杆支护的优越性和围岩破坏分区及破坏深度逐步向深部发展的规律,针对煤矿深部巷道采用加长或全长锚固锚杆支护时,锚杆的锚固段整体受力不均,抗剪切承载能力低,而端锚锚杆无法适应其大变形缺点的问题,建立了两段锚预应力锚杆支护模型。运用理论计算和数值模拟的手段研究了两段锚预应力锚杆锚固段的受力特征和承载能力,并进行了算例对比分析。结果表明:两段锚分区锚固的支护方式明显改变了加长或全长锚固锚杆锚固段的剪应力曲线变化趋势,使原本呈负指数变化趋势的剪应力曲线变得平缓,提高了锚杆锚固段的剪切承载能力;在相同预紧力作用下,与端锚锚杆相比,明显降低了锚杆锚固段的荷载和剪切应力;在不同预紧力下,两段锚预应力锚杆的两锚固段可分别起到围岩不同变形时期端锚锚杆的支护作用,继续发挥端锚支护的优越性。
Based on the superiority of end anchor and bolting support and the gradual deepening rule of the destruction of surrounding rock and the depth of destruction, aiming at the long-term or full-length anchor bolt support in the deep mine roadway, Both of them have low anti-shear bearing capacity, but the end anchor bolt can not adapt to the problem of large deformation. Two types of anchor prestressed anchor support model are established. By means of theoretical calculation and numerical simulation, the force characteristics and bearing capacity of two sections of anchor prestressed anchor are studied, and the comparative analysis is carried out. The results show that the anchoring support of two sections of anchors greatly changes the tendency of the shear stress curves of the anchored sections of the extended or full length anchor bolts, and the curve of the shear stress that has been changed negatively exponentially flattens, Under the same pretightening force, compared with the end anchor bolt, the load and shear stress of the anchorage section of the anchor bolt are obviously reduced. Under different preload, the anchor prestress of the two sections The two anchorage sections of the anchor rod can respectively play the supporting function of the end anchor bolt during different deformation periods of the surrounding rock and continue to exert the superiority of the end anchorage support.