高地温隧道干热环境中喷射混凝土与岩石黏结强度  

Bond Strength of Shotcrete with Rock in Dry and Hot Environment of High Ground Temperature Tunnel

作　　者：崔圣爱[1] 李江渭[1] 叶跃忠[1] 杨红艳[1] 

机构地区：[1]西南交通大学土木工程学院,四川成都610031

出　　处：《建筑材料学报》2013年第4期663-666,682,共5页Journal of Building Materials

基　　金：国家自然科学基金资助项目(51008253);中央高校基本科研业务费专项资金资助项目(SWJTU12CX072)

摘　　要：采用改进的钻芯拉拔法测试模拟高地温隧道干热环境中喷射混凝土(C25,C30)与岩石的7,28d黏结强度,并通过三维视频显微镜观察喷射混凝土与岩石黏结界面的微观形貌,探讨高地温热害对喷射混凝土与岩石黏结强度的影响规律及影响机理.结果表明:由于改进的钻芯拉拔法是在传统钻芯拉拔法基础上增加了可转动的铰接设置,减少了因加载偏心引起的黏结界面的撕裂破坏,从而保证了黏结强度测定结果更加准确和稳定;与20℃标准养护工况相比,干热养护工况下喷射混凝土与岩石黏结强度严重倒缩,甚至有的喷射混凝土与岩石脱黏开裂;热害使喷射混凝土与岩石28d黏结强度倒缩比7d黏结强度更加严重.干热下水分散发快,水泥水化中止早,水化产物不致密,混凝土强度发展不够,再加上干热下混凝土干缩大,因此干热下喷射混凝土与岩石黏结强度降低.In order to explore the influence of heat harm in high ground temperature tunnel on the bond strength of shotcrete with rock, the bond strengths of C25, C30 shotcrete with rock for 7 d and 28 d ages in dry and hot environment were determined by improved core-drilling and drawing method, and the micro scopic structures of bonding interfaces between shotcrete and rock were observed by three-dimensional vid eo microscope. The results show that the improved core-drilling and drawing method, based on traditional one with rotary hinge join additionally installed, can diminish the dilaceration of bond interface caused by loading eccentricity and can ensure the determined results more accurate and stable. Compared with the 20 ℃ standard curing condition, the bond strength of shotcrete with rock decreases seriously under dry and hot environment, and even results in debond and crack. Due to heat harm, the bond strength for 28 d age decreases significantly as compared to that for 7 d age. Due to fast distribution of water and suspension of cement hydration and larger dry shrinkage of concrete, the bond strength of shotcrete with rock decreases.

关 键 词：高地温 干热环境 喷射混凝土 黏结强度 

分 类 号：TU528.53[建筑科学—建筑技术科学]