预紧力锚杆作用下锚固体内应力及锥形体特征分析

    Analysis of Stress and Conical Body Characteristics of Anchorage Body Under the Action of Pretensioned Bolt

    • 摘要: 在煤矿巷道预应力锚杆支护中,锚固体内锥形体的形成是预应力锚杆能发挥作用的重要原因。为了研究预应力锚杆作用下锚固体内的应力分布和锥形体的形成规律,采用ANSYS有限元分析软件,建立了含有单根锚杆的锚固体模型,并施加锚杆预紧力和围岩压力,研究了含预应力锚杆的锚固体内应力状态和锥形体的形成规律。结果显示:锚固体内的水平应力呈现出两头大中间小的“凹”形;锚固体内锥形体呈中空的“拳头”状;在靠近锚杆端部位置,锚固体内会产生一定的拉应力;锥形体轮廓与锚杆的夹角随着围压的增大而减小,随锚杆预紧力的增大而增大;锥形体端部高度随围压的增大而增大,随锚杆预紧力的增大而减小。

       

      Abstract: In the support of prestressed anchor in coal mine roadway, the formation of cone body in anchorage body is an important reason for prestressed anchor to play a role. In order to investigate the formation laws of the conical body in the anchorage body, ANSYS was used to build anchorage body model containing a single anchor bolt. Then, pre-tightening force and surrounding rock pressure were applied on the anchor bolt and conical body respectively. The stress state inside the anchorage body and the formation of the conical body were studied. The results show that the horizontal stress inside the anchorage body shows a concave shape, i.e., the horizontal stress is higher in both end surfaces of the anchorage while that is smaller in the middle of the anchorage body. The conical body shows a “fist” shape. In some areas near the end of the anchor bolt, the anchorage body is subjected to tensile stress. The angle between the contour line of the conical body and the anchor decreases with the increase of the surrounding stress while that increases with the increase of the pre-stress. However, the height of the surface of the conical body increases and decreases with the increase of the surrounding press and pre-stress separately.

       

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