盾构下穿施工对既有桩基承载性能的影响研究  

Study on Effects of Shield Tunneling Underneath Existing Pile Foundation on Bearing Capacity

作　　者：郭院成[1] 郜新军[1] 郭孝坤 李智[1] 

机构地区：[1]郑州大学土木工程学院,郑州市450001

出　　处：《公路》2017年第3期236-242,共7页Highway

基　　金：高等学校博士学科点专项科研基金;项目编号20134101120009;河南省教育厅科学技术研究重点项目;项目编号14A560014

摘　　要：针对地铁盾构隧道近接桩基施工情况,利用有限元软件,在考虑前方土体受到刀盘施工扰动、土仓压力、盾尾注浆作用等施工参数下,对盾构隧道动态施工中正上方桩基的承载性能进行了数值计算。结果表明,盾构施工对桩基沉降和承载力损失较大的区域主要集中在刀盘距桩轴线+6^-12m之间;盾构正下方穿越既有桩基时,存在一个特定安全施工距离,约为3m;盾构隧道施工前桩基承受的荷载不同,盾构施工过程对桩基承载力的影响也就会不同。In order to study the bearing capacity of single pile when the shield tunneling machine drives below the pile foundation,a numerical model which involves the parameters such as the construction disturbance of front soil caused by the shield machine cutter,soil-pressure in the soil chamber,grouting in the shield tail,and the grouting with two phases of clotted and not clotted states is built and calculated based on the finite element software.The results show that there is a certain safe distance of construction which is about 3mwhen the shield tunneling machine drives below the pile foundation.The settlement and the bearing capacity loss of the pile have great changes mainly occur in the area where the cutter is apart from the pile axis from ＋6 mto-12 m.The bearing capacity of the pile foundation influenced by the shield tunneling depends on the load effect on the pile before the construction of shield tunnel.

关 键 词：盾构隧道 桩基 桩身沉降 桩身轴力 桩顶荷载 研究 

分 类 号：U455.43[建筑科学—桥梁与隧道工程]