多次分段控制注浆斜向预应力钢锚管锚固机制研究

为了研究多次分段控制注浆斜向预应力钢锚管锚固机制,必须搞清楚多次分段控制注浆斜向预应力钢锚管的结构形式、加固作用机制、适用范围及设计计算方法,依托广州北三环高速公路K42边坡对不同自由段长度预应力钢锚管承载力试验,分析预应力钢锚管的有效锚固段长度,并与普通锚杆、普通钢锚管承载力对比,试验结果表明,在强风化花岗岩地层,多次分段控制注浆预应力钢锚管极限承载力与普通锚杆提高约50%,预应力钢锚管的有效锚固长度为6 m;通过Plaxis2D软件对预应力钢锚管锚固机制分析,分析结果表明,劈裂注浆技术对滑坡稳定性的改善并不显著,锚固与劈裂注浆技术共同作用对滑坡稳定性改善显著。现场试验及数值模拟结果对正确分析多次分段控制注浆斜向预应力钢锚管加固作用机制和工程设计应用具有一定的参考价值。

Study on anchoring mechanisms of inclined prestressed steel anchor pipes controlled by multi-stage grouting

In order to study the anchorage mechanisms of multi-stage control grouting inclined prestressed steel anchor pipes,it is necessary to make clear the structural form,reinforcement mechanism,scope of application and design calculation method of multi-stage control grouting inclined prestressed steel anchor pipes. Taking K42 slope of Guangzhou north third ring expressway as an objective,bearing capacity tests of prestressed steel anchor pipes with different free lengths were carried out. The effective anchorage length of prestressed steel anchor pipes was analyzed,and comparisons of the bearing capacity among prestrsssed steel anchor pipes,common anchor rods and common steel anchor pipes. The test results show that the ultimate bearing capacity of the prestressed steel anchor pipes increases by 50% than that of common anchor rods and the effective anchorage length of the prestressed steel anchor pipe is 6 m. Anchoring mechanisms of prestressed steel anchor pipes by Plaxis2 D software were performed. It is shown that the improvement of the stability of landslides is not obvious by the crack grouting technology while that combination of the crack grouting technology and the prestressed steel anchor pipes plays a obvious role in enhancing the stability of landslides. The research work is of certain reference value for correct analysis of reinforcement mechanisms and engineering design application of multi-stage control grouting inclined prestressed steel anchor pipes.