新型预应力锚索内部监测结构试验研究

Experimental study on internal monitoring structure of a new prestressed anchor cable

针对预应力锚索内部应力监测难题,研发了一种新型预应力锚索内部应力监测结构,并通过破坏性张拉试验和多级荷载反复张拉试验对该监测结构进行测试。测试结果表明锚索达到屈服荷载前,新型监测结构与锚索同步变形,具有较高的一致性;高荷载反复张拉13次可消除加工监测结构引起的残余应变,提高监测精度;通过多级别反复张拉试验建立了监测结构应变与锚索应力之间的转换公式,残余应变消除后,采用转换公式测定锚索应力误差小于2%;为预应力锚索内部应力监测提供了一种新的有效可行的监测技术。

On account of their difficult internal stress monitoring,a new type of internal stress monitoring structure for pre-stressed anchor cables is developed and then tested by the destructive tension tests and the repeated tension tests under multi-levelload.The test results show that before reaching the yield load,the new monitoring structure deforms synchronously with the anchor cable,representing a relatively high consistency.The residual strain caused by processing of monitoring structure is eliminated by 13 times of repeated tensioning under high loads,thus improving the accuracy.After elimination of the residual strain,a conversion formula is established between strain of monitoring structure and stress of anchor cables.The error of stress of anchor cables measured by this conversion formula is smaller than 2%.This study may provide a new effective and feasible monitoring technology for the internal stress monitoring of pre-stressed anchor cables.