Abstract: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, C30shotcrete with rock for 7d and 28d 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 video 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 28d age decreases significantly as compared to that for 7d 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.