加锚预制裂隙类岩体锚固机制试验研究及其数值模拟

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。

Experimental study and numerical simulation of anchoring mechanism of anchored rocklike material with prefabricated fracture

To investigate the anchoring mechanism and its influential factors of the bolt, a series of uniaxial breaking tests is conducted on the specimen with prefabricated fracture anchored with a single row bolt. A concept of the main-control crack (i.e., one or several large cracks controlling the strength weakening and the ultimate failure) is proposed. Under different conditions of anchorage, the main-control crack of specimen have different occurrences. In the effective anchoring zone, there are two types of main-control cracks observed in the fractured specimens, called the horizontal main-control crack and vertical main-control crack. It is found that specimens without rock bolt or with the cracks beyond the effective anchoring zone only have the vertical main-control crack. Acoustic emission and stress monitoring data show that the bolt can delay the initiation of the main-control cracks and improve the strength of the fractured specimens. Additionally, the stress intensity factors on the tip of cracks under different anchoring conditions are calculated using ANSYS software. Then the relationship among the anchoring spacing, anchoring angle and the stress intensity factor is obtained. The coalescence modes of main-control cracks are also simulated under different anchoring spacings by using FLAC3D software, and numerical results agree well with the experimental results.