上软下硬地层碴土改良试验及应用研究  

Soil Conditioning Test for Soft Upper and Hard Lower Mixed Stratum and Its Application

作　　者：叶新宇[1] 王树英[1] 肖超[1] 阳军生[1] 周纯择 

机构地区：[1]中南大学土木工程学院,长沙410075

出　　处：《现代隧道技术》2015年第6期147-153,共7页Modern Tunnelling Technology

基　　金：国家科技支撑计划课题(No.2012BAK24B02);国家自然科学基金青年项目(No.51208516)

摘　　要：针对南昌地区上覆富水砂砾石下卧泥质粉砂岩地层盾构掘进过程中存在碴土改良困难的问题,文章首先通过矿物成分分析及筛分试验得到了泥质粉砂岩的粘土矿物成分高（40.5%）、富水砂砾石微细颗粒含量低（29%）的特点,确定了盾构掘进时将极有可能出现结泥饼以及喷涌的问题,以此提出了采用泡沫剂进行碴土改良方案,并在考虑泡沫剂类型、碴土级配及含水率等影响情况下通过室内试验,得到了最优的室内试验改良参数,即刀盘在砂砾与泥质粉砂岩的面积比分别为2∶1,1∶1和1∶2时的泡沫添加比分别为25%-30%,37.5%-45%和40%-50%。最后,以所得试验参数为基础,考虑了室内试验与现场施工的差异因素,推导出了室内试验参数应用于施工的计算公式。通过现场应用及施工效果反馈,确定了从室内试验到参数推导的碴土改良方案具有良好的适应性。In light of the problems that exist regarding soil conditioning during shield tunnelling in a stratum with water-rich sandy gravel at the upper part and argillaceous siltstone at the lower part in the Nanchang area, this paper presents the characteristics of the encounterted stratum-such as a high clay content （40.5%） in argillaceous siltstone and low fine particle eontent （29%） in sandy gravel-through mineral composition analysis and screen test and proposes a soil conditioning scheme with a foaming agent to address the problems that may occur during shield tunnelling, such as mud caking and gushing. The optimal conditioning parameters determined by laboratory tests that considered foaming agent type, soil gradation and moisture content are presented, namely, the proportions of the added foaming agent are 25%-30%, 37.5%-45% and 40%-50% when the ratios between the sandy gravel and argillaceous sihstone are 2 ： 1, 1 ： 1 and 1 ： 2, respectively. A relevant calculation formula based on the test parameters and the differences between the laboratory tests and site construction is given.

关 键 词：盾构 上软下硬 碴土改良 室内试验 参数计算 

分 类 号：U455.4[建筑科学—桥梁与隧道工程]