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为研究锚杆对裂隙岩体的锚固机制及其影响因素,对预制锚固单排裂隙试件进行单轴破断试验。提出了主控裂纹的概念,即控制试件强度弱化和最终破坏的一条或几条大裂纹称为主控裂纹。在不同的锚固条件下主控裂纹会有不同的产状:在有效锚固范围内,裂隙试件具有横向和纵向两类主控裂纹,而在无锚或有效锚固范围之外的试件仅有纵向一条主控裂纹贯通。通过声发射和应力监测表明,在有效锚固范围内锚杆能延迟主控裂纹产生和提高裂隙试件强度。另外,利用ANSYS软件对不同锚固条件下的裂隙尖端应力强度因子进行数值计算,得到了锚固距离和锚固倾角与裂隙尖端应力强度因子之间的关系;通过FLAC3D模拟了不同锚固距离下主控裂纹贯通模式,数值模拟与试验结果比较吻合。
In order to study the anchoring mechanism of rock bolt on fractured rock mass and its influencing factors, the uniaxial rupture test of prefabricated single row fracture specimens was carried out. The concept of master crack is proposed, that is, one or several large cracks that control the strength of the specimen to be weakened and eventually destroyed are called master cracks. In different anchorage conditions, the main cracks will have different occurrences: in the effective anchoring range, the fractured specimens have two kinds of master and control cracks in the horizontal and vertical directions, while the specimens without anchoring or effective anchoring range have only Longitudinal a master crack through. Acoustic emission and stress monitoring indicate that the anchor can delay the crack initiation and improve the strength of the crack specimen in the range of effective anchorage. In addition, ANSYS software is used to calculate the stress intensity factor of crack tip under different anchorage conditions, and the relationship between anchoring distance and anchorage angle and stress intensity factor of crack tip is obtained. Through FLAC3D simulation, The model, numerical simulation and test results are in good agreement.