复合地层盾构隧道泡沫改良碴土试验研究  

Experimental Study of Soil Conditioning with Foam for the Shield Tunnel in Composite Stratum

作　　者：周吉学 ZHOU Jixue(School of Civil Engineering and Architecture,Wuhan University of Technology,Wuhan 430070;China Railway 20th Bureau Group Corporation,Xi'an 710016)

机构地区：[1]武汉理工大学土木工程与建筑学院 [2]中铁二十局集团有限公司

出　　处：《现代隧道技术》2019年第4期194-199,共6页Modern Tunnelling Technology

基　　金：中铁二十局集团有限公司技术开发课题(CR2005-佛莞-KJYF-SJ2016-001)

摘　　要：盾构长距离穿越复合地层时,会出现喷涌、刀盘结泥饼、刀盘扭矩过大、刀具磨损严重等施工问题。文章通过自制泡沫发生装置,进行了泡沫改良碴土试验,分析了不同泡沫注入率下全风化、复合、强风化地层碴土的各项物理参数变化情况。试验结果表明:注入泡沫可有效降低碴土的渗透性系数、粘聚力和内摩擦角;使用注入率为20%的泡沫处理改良碴土,其渗透性系数可降低至10^-6m/s,满足盾构隧道施工的抗渗要求;盾构掘进强风化土、复合土、全风化土时,满足理想状态下土体"塑性流动"要求的最优泡沫注入率分别为30%,10%和10%。Blow-out,mud cake,high torque of cutterhead and serious wear of cutting tools could be encountered during long distance shield driving in the composite stratum.A foam based soil conditioning experiment was carried out by a self-made foam generator,and the variations of various physical parameters of soils of completely weathered stratum,composite stratum or strongly weathered stratum under different injection rates of foam were analyzed.The results show that the permeability coefficient,cohesion and internal friction angle of soils could decrease effectively by foam injection;the permeability coefficient may decrease to 10^-6 m/s by the foam with injection rate of 20%,meeting the requirement of permeability resistance of shield tunnel construction;the optimal foam injection rates meeting the requirement of"plastic flow"of soil mass under ideal condition are 30%,10%and 10%respectively during shield construction in strongly weathered stratum,composite stratum and completely weathered stratum.

关 键 词：复合地层 盾构隧道 碴土改良 泡沫 注入率 渗透性 抗剪强度 

分 类 号：U455[建筑科学—桥梁与隧道工程]