深基坑开挖爆破对桩锚支护结构的影响及其机理研究  

Influence of blasting in deep excavations on anchored pile supporting structures and its mechanism

作　　者：孙鹏昌 覃卫民[2] 陈明[1] 卢文波[1] SUN Pengchang;QIN Weimin;CHEN Ming;LU Wenbo(State Key Laboratory of Water Resources and Hydropower Engineering Science,Wuhan University,Wuhan 430072,China;State Key Laboratory of Geomechanics and Geotechnical Engineering,Institute of Rock and Soil Mechanics,Chinese Academy of Sciences,Wuhan 430071,China)

机构地区：[1]武汉大学水资源与水电工程科学国家重点实验室,武汉430072 [2]中国科学院武汉岩土力学研究所岩土力学与工程国家重点实验室,武汉430071

出　　处：《振动与冲击》2021年第22期144-150,共7页Journal of Vibration and Shock

基　　金：国家自然科学基金(41672314,51779193);湖北省技术创新专项重大项目(2017ACA102)。

摘　　要：研究深基坑开挖爆破对桩锚支护结构的影响是确保深基坑安全稳定的关键性问题。依托厦门机场路一期工程分离式车行隧道深基坑爆破开挖工程,基于现场爆破振动监测数据建立了桩锚支护深基坑有限元数值计算模型,分析研究了深基坑开挖爆破作用下,桩锚支护结构的爆破振动响应规律,支护桩的塑性损伤分布以及预应力锚索的拉力变化规律。研究结果表明:紧邻爆区的桩身最大爆破振动速度超过30 cm/s,远大于可参照的爆破振动安全控制标准,桩顶爆破振动存在放大效应;预应力锚索不同位置处的爆破振动速度远小于桩身,且与爆心距无明显相关性;爆破加载作用在波阻抗较小的岩土体边界上,易使支护桩与岩土体的交界面产生受拉损伤;爆破加载使不同排预应力锚索的拉力产生重新分配调整。结合结构动力学和波动力学理论简要分析了深基坑开挖爆破对桩锚支护结构影响的作用机理。研究结果可为桩锚支护深基坑开挖爆破设计提供参考。Studying the influence and mechanism of blasting on anchored pile supporting structures is a key issue to ensure the safety and stability of deep excavations.Relying on the deep excavation in Xiamen airport road phase I,a finite element model for deep excavations was established.The blast vibration of the anchored pile supporting structures,the plastic damage distribution of the supporting piles,and the variation of pulling force in prestressed cables were studied.The results show that the maximum blast vibration of the pile body in the adjacent blasting area is much greater than that stipulated in referred blast vibration safety control standards,and there is an amplification effect of the blast vibration at the top of the pile.The blast vibration at different positions of the prestressed anchor cables is much smaller than that of the pile body,and there is no obvious correlation with the distance from explosive source.It is easy to cause tensile damage to the interface between the rock and the supporting pile if the wave impedance of the rock is rather small.The blast loading causes the readjustment and redistribution of the tensile force in the prestressed anchor cables.Based on the structural dynamics and wave dynamics theory,the influence mechanism of blasting on anchored pile supporting structures was explored.

关 键 词：深基坑 桩锚支护 爆破加载 数值模拟 动力响应 

分 类 号：TD235[矿业工程—矿井建设]