无粘结预应力锚索孔摩阻力及锚索结构改进的试验研究

Experimental study on frictional resistance and structure improvement of unbonded prestressed anchor cable

利用一种新型让压构件的力学特性,采用现场试验的方法对锚索孔摩阻力进行测试。结果显示,普通无粘结预应力锚索孔摩阻力达到孔口拉力的25%~40%,且随着锚索自由段长度的增加呈现加速增长的趋势。为了进一步研究锚索孔摩阻力形成的主要因素,对单根钢绞线的孔摩阻力进行测试,通过对比试验成果的分析,认为锚索居中和绑扎方式是影响孔摩阻力的重要因素。在对锚索孔摩阻力主要影响因素分析的基础上,对锚索内部结构进行改进,经室内试验验证,改进后的锚索孔摩阻力得到有效减小。

With the mechanical properties of a new kind of yielding component,an in situ experiment is made on the frictional resistance of anchor cable. The result shows that the frictional resistance can reach 25% ~ 40% of the tensile force of the orifice for the conventional unbonded prestressed anchor cable and show a trend of accelerated increase along with the increase of the length of the free section of it. In order to further study the main factors of the formation of the anchor cable frictional resistance,the frictional resistance of a single strand is tested. Through the analysis on the comparative experiment result,it is considered that the centering and binding modes of the anchor cable are the important factors to impact the the frictional resistance. Based on the analysis made on the main factors to impact the frictional resistance of the anchor cable,the internal structure of the anchor cable is improved. It is certified through the relevant indoor experiment that the friction-resistance of the anchor cable is effectively decreased after the improvement concerned.