分层多次高压注浆预应力锚固试验与数值模拟

Experimental Study and Numerical Simulation of Pre-stressed Anchorage Technology with Hierarchical Multi-time High Pressure Grouting

为了治理露天矿山破碎岩质高陡边坡,增强边坡稳定性,从分析锚杆预应力锚固技术和高压注浆技术机理入手,采用水力劈裂应力场计算得出高压劈裂的浆液走向,提出了结合2种技术优点的分层多次高压注浆预应力锚固技术。然后,通过在实验室中对普通锚固体与分层多次高压注浆劈裂形成的锚固异形体模型分别进行拉拔对比试验,采集锚杆应力分布数据,分析其应力传递规律,得出分层多次高压注浆预应力锚固技术能使锚固段的承载力提高约39.25%,同时可以避免应力集中。最后,利用FLAC3D软件建立模型进行模拟,取4组不同起劈宽度和4组不同的起劈长度,施加相同的拉拔力,分别进行对比研究,分析其内部应力分布及传递规律。研究结果表明:相对于普通锚固异形体,分层多次高压注浆劈裂形成的锚固异形体可以承担更多的剪应力,并且随着劈裂程度的增大,浆脉的长度更长,起劈宽度更大,浆脉应力场的影响力更大,锚固效果更好。

In order to treat the broken-rock high and steep slope of open-pit mine and improve the slope stability, the slurry flow of high pressure splitting grouting are obtained by calculating the stress field of hydraulic fracture ,based on mecha- nism analysis of pre-stressed anchorage and high-pressure grouting. The pre-stressed anchoring technique of the hierarchical multi-time high pressure grouting combining with advantages of two techniques above is put forward. Then, the contrastive pull- off tests of anchoring shaped models formed by the ordinary anchor solid and multi-time layered high pressure grouting solid are made. The stress distribution data of anchoring bolt are collected and its stress transmission rule is analyzed. It is concluded that the hierarchical multi-time high pressure grouting technique improved the bearing capacity of the anchoring by 39.25%. Meanwhile,it can avoid from the stress concentration. Finally, FLAC3D is used to build a simulation model. Experiments that the same put-off force bears on four groups of different splitting width and four different heights are respectively made to contrast and analyze the distribution and transmission rule of the internal stress. The results showed that comparing with the ordinary an- chorage, the hierarchical multi-time high pressure grouting can bear much more shearing strength. With the increase of split- ting, the slurry vein length will be longer, the splitting width will be wider and the stress field of slurry vein will have a more significant effect. These result in better anchoring performance.