摘要
地下空间注浆加固后的围岩常常由于爆破施工而遭到二次破坏,造成再次渗漏或失稳.本文通过模型试验,研究了地下空间注浆加固围岩掌子面爆炸条件下,由于爆破荷载导致次生开裂时的爆炸压力、质点加速度和动应变传播规律,并获得了地下空间一定注浆加固围岩在此时的动应变阈值和质点加速度阈值.结果表明,注浆材料强度、装药量是控制次生裂缝的主要因素,按水灰比为0.35,水泥标号为42.5R,配合比为1∶1选择的砂浆灌注的裂缝,产生次生开裂的动应变阈值为1×10-3,质点加速度阈值为1 500 m/s2.掌子面爆炸(包括端墙爆和贴爆)条件下,空气冲击波超压具有比较显著的衰减规律和低压下可重复性,已加固裂缝产生次生开裂的压力阈值可用一条拟合曲线来表示.
Grouted reinforced surrounding rock in underground space is often damaged by blasting loads, and appears leakage and loses stability again. Based on model tests, change regulations of the blasting pressure, the particle acceleration and the dynamic strain when the reinforced surrounding rock appears secondary cracks by blasting loads were studied after the explosion on the end face of underground space, and the dynamic strain and acceleration thresholds were obtained. The results show that the strength of injected-grout material and the charge quantity are primary factors to control the secondary cracks. For the grouted cracks with the materials of ratio between water and mortar of 0.35, 42. 5R grade cement and the proportion of cement to sand of 1 ： 1, the dynamic strain and the acceleration thresholds inducing secondary cracks are 1 × 10^-3 and 1 500 m/s^2, respectively. Under the condition of explosion on the end face（ including the explosion on end face and the close explosion）, airblast overpressure has obvious attenuation character and the low pressure repeatability. The secondary cracking pressure threshold of grouted reinforced cracks can be expressed with one fitting equation.
出处
《中国矿业大学学报》
EI
CAS
CSCD
北大核心
2007年第3期360-364,共5页
Journal of China University of Mining & Technology
基金
国家自然科学基金项目(40372123)
教育部新世纪优秀人才支持计划项目(NCET-04-0486)
江苏省"青蓝工程"项目
关键词
地下空间
注浆
围岩
抗爆
阈值
underground space
grouting
surrounding rock
anti-explosion
threshold value
