基于不同测定方法的热害环境喷射混凝土黏结性能分析

Analysis on Bond Performance of Shotcrete Based on Different Testing Methods in Thermal Damage Tunnel

本文以隧道热害环境问题为背景，利用模拟热害环境设计和湿喷混凝土技术对热害环境2种强度等级（C25和C30）喷射混凝土与岩石的黏结性能进行试验研究。为保证结果可靠，对岩石大板同时采用劈裂法和改进的钻芯拉拔法（直拉法）测定黏结强度。试验结果表明：相对于标准养护工况，干热环境和湿热环境均引起黏结强度倒缩；2种测定方法测得喷射混凝土（C25、C30）黏结强度随温度的变化趋势一致；劈裂法测定的黏结强度普遍大于钻芯拉拔法测定结果，差值范围5%～15%；2种测定方法各有优点，使用时应尽可能控制对黏结强度测定不利的影响因素。

Against the background of thermal damage environment problem of tunnel, the experimental study on the bond performance between shotcrete and rock for two kinds of strength grade （C25 and C30） shotcrete was carried out by using simulating thermal damage environment design and wet shotcrete technology. In order to ensure the reliability of experimental result, the bond strength of the same slab was measured by splitting method and improved core-drilling and pull-stripping method at the same time. The experimental results showed that： comparing with standard curing condition, retraction phenomenon of the bond strength caused by thermal damage was reflected in hot-dry environment and hot-humid environment. Based on the results obtained by the two measuring methods, the changing tendency of the bond strength of C25 or C30 shotcrete was consistent with the change of temperature. The bond strength measured by the splitting method was generally higher than that measured by the core-drilling and pull-stripping method, with difference range of 5 %-15%. As there are respective advantages and disadvantages in the two measuring methods, adverse affecting factors on the measurement of bond strength should be controlled and reduced as far as possible during the application of the measuring methods.