Tunnel drilling and blasting excavation is a process of"successive detonation".Its load size,action time and action objects are significantly different from conventional cyclic dynamic loads.The damage to surrounding rock induced by explosion loads is also reflected in the following a cumulative process.Based on explicit dynamics and"restart"technology,this paper establishes a numerical model of cumulative damage to surrounding rock that can simulate the characteristics of single-hole progressive cyclic blasting,and conducts research on the cumulative damage rules of surrounding rock for single-hole progressive cyclic blasting.The results show that:①Based on the comparison of the distribution characteristics of the surrounding rock damage area induced by a single blast,the reliability of the model is verified;②The degree and range of damage to the surrounding rock obtained by considering the single-hole progressive cyclic blasting are significantly more severe than that of a single blast,about increase by 50%.Therefore,it is difficult to reveal the actual situation of rock mass damage using the traditional analysis method simplified to a single blast,which is unsafe;③The amount of damage to surrounding rock induced by blasting increases with the increase in blast center distance.The evolution characteristics of the Boltamann function(S-shaped curve).In the actual application process,when assessing the degree and scope of damage to the surrounding rock at the current location,the additional cumulative damage caused by adjacent footage cycles should be considered.The damage value can be taken from the current single blasting operation.1.5 times the damage value.
关键词
累积损伤/数值模拟/爆心距/钻爆法
Key words
cumulative damage/numerical simulation/burst center distance/drilling and blasting method
维普
万方数据