锚杆杆体–砂浆界面力学特性的剪切速率效应研究

Study of effect of shear velocity on mechanical characteristics of bolt-grout interface

中等应变率下锚固系统的力学响应是地震作用下支护结构安全性分析与评价的关键问题,特别是锚固界面通常为锚固系统中的薄弱环节,其在动态荷载下的力学特性至关重要。开展不同剪切速率条件下锚杆杆体–砂浆界面的直剪试验,详细分析不同法向应力下剪切速率对峰值剪应力、抗剪强度参数以及法向变形性能的影响。试验结果表明,在中等应变率条件下,随剪切速率增大,锚杆杆体–砂浆界面峰值剪应力总体表现为先迅速增加后基本保持不变的趋势;黏聚力和剪胀量均呈现出先增加后减小的变化趋势。试验成果可为中等应变率下锚固系统动力响应分析提供基础数据。

The mechanical response of the anchorage system under intermediate strain rate conditions is the key issue in the analysis and evaluation of the safety of the support structure when subjected to earthquake, considering that the bolt-grout interface is the weakest element in the anchoring system generally; its mechanical behavior under dynamic load are extremely important. Therefore, direct shear tests of bolt-grout interface are conducted under different levels of shear rate(0.06-30 mm/min). The effects of shear rate on peak shear stress, shear strength parameters and normal deformation behavior under different normal stresses are analyzed detailedly. The test results show that under intermediate strain rate conditions, with the increase of shear rate, the peak shear stress first increase rapidly then almost keep constant, whereas cohesion and normal displacement show a change trend of first increase and then decrease. The test results can provide basic data for the dynamic response analysis of the anchorage system under intermediate strain rate condition.