重复荷载作用下岩锚体系力学特性和黏结性能试验研究

为研究岩锚体系在重复荷载作用下的性能，设计2组室内试验，试验采用钢筋锚固混凝土基体模拟岩锚体系。通过对体系施加重复荷载，得到在重复荷载作用下锚的拉拔力与位移的全过程；利用预埋在体系内部的应变片，实测锚束体–灌浆体界面的黏结应力分布及其变化规律，提出在重复荷载作用下的钢筋–混凝土界面的黏结应力分布特点。试验结果表明：2组试件在重复荷载作用下的破坏形式均为锚束体从灌浆体中拔出。为描述体系的破坏过程，基于试验结果及已有的研究成果，提出破坏过程中荷载位移变化的4个阶段。在此基础上，探讨破坏过程中界面上黏结力的变化特性，并根据不同阶段的临界位移，提出重复荷载作用下岩锚体系的设计建议。

EXPERIMENTAL RESEARCH ON MECHANICAL BEHAVIOR AND BOND PERFORMANCE OF ROCK-ANCHOR SYSTEM SUBJECTED TO REPEATED LOAD

In order to study the performance of rock-anchor system under repeated load，two tests were carried out. In the tests，the rock-anchor system was modelled by anchoring steel bar into concrete block；and then repeated load was acted on the system. From the tests，a full relation between load and displacement for the system has been obtained. By using embedded foil strain gauges，bond shear stresses were measured and the distribution of bond shear stress along the bar was achieved. The test results show that both specimens fail in anchor body pulling out from grout body. For the purpose to describe this phenomenon，a load-displacement constitutive relationship with four phases is developed on the strength of previous research. Based on the results，the reasons for bond stress change are discussed；and design recommendations based on critical displacements in different phases are suggested.