摘要
研究目的:盾构掘进过程中,渣土的流动性、止水性、流塑性是盾构掘进效率及盾构机使用寿命影响的主要影响指标,因此对不同地层渣土性质的改良以满足施工要求极其重要。本文针对成都地区粉质黏土地层盾构施工,研发适用于粉质黏土地层专用渣土改良剂分散型泡沫剂。通过室内对渣土容重、流动度、黏附性等的测定,筛选出最好的改良剂配方。对成都地铁7号线盾构区间强风化泥岩地层渣土进行改良试验,分析不同泡沫剂对现场盾构掘进参数、泡沫消泡量、渣土性状的影响。研究结论:(1)通过配比试验及发泡效果检测,得到了多组泡沫稳定性和同类产品性能相当甚至更优的基准泡沫剂,泡沫半衰期在20 min左右,5 min消泡率在3%以内,完全满足盾构施工要求5 min内消泡不大于5%的指标;(2)针对粉质黏土地层特点,研制了分散型泡沫剂S53-JSSA-6(DCA),通过室内渣土改良试验,验证了其对粉质黏土的改良效果,加入分散型泡沫剂后较大程度地降低了粉质黏土的黏附性,可降低盾构在粉质黏土地层的结泥饼风险;(3)分散型泡沫剂DCA在强风化泥岩地层的应用试验表明,分散型泡沫剂的产品性能能达到巴斯夫同类泡沫剂,完全满足现场强风化泥岩地层的盾构施工要求;(4)本试验结果可为粉质黏土地层盾构隧道施工渣土改良研究问题提供参考。
Research purposes: In the process of shield tunneling,the fluidity,water resistance and flow plasticity of the soil are the main indexes affecting the tunneling efficiency and the service life of the shield tunneling machine. Based on the shield construction of silty clay formation in Chengdu area,this paper researched and developed the dispersing foam agent for the special soil improver for silty clay formation. Through the determination of bulk density,fluidity and adhesion of ballast in the room,the best formulation of improver was selected. In this paper,the improvement test of highly weathered mudstone stratum soil in the shield tunnel of Chengdu metro line 7 is carried out,and the influence of different foam agents on the tunneling parameters,foam defoaming amount and soil properties of shield tunnel is analyzed.Research conclusions:(1) Through the ratio test and foaming effect test,several groups of benchmark foaming agents with the same or better foam stability and similar product performance were obtained. The foam half-life was around20 min,and the defoaming rate was within 3% in 5 min,which fully met the requirement of defoaming rate not more than 5% in 5 min of shield construction.(2) According to the characteristics of silty clay stratum,the dispersing foam agent S53-JSSA-6(DCA) was developed,and its improving effect on silty clay was verified through the laboratory experiment on improving soil. After adding dispersing foam agent,the adhesion of silty clay was greatly reduced,which could reduce the risk of mud cake formed by shield in silty clay stratum.(3) The application test of DCA in strongly weathered mudstone stratum shows that the product performance of DCA is up to that of BASF foam agent and fully meets the shield construction requirements of strongly weathered mudstone stratum.(4) The research results can provide a reference for the research on the soil conditioning of silty clay stratum shield tunnel construction.
作者
王明胜
路军富
罗奥雷
WANG Mingsheng;LU Junfu;LUO Aolei(China Railway City Development and Investment Group Co.Ltd,Chengdu,Sichuan 610000,China;State Key Laboratory of Geohazard Prevention and Geoenvironment Protection,Chengdu University of Technology,Chengdu,Sichuan 610059,China)
出处
《铁道工程学报》
EI
北大核心
2020年第5期74-79,共6页
Journal of Railway Engineering Society
基金
国家自然科学基金(51978088)
SKLGP国家重点实验室自主课题(SKLGP2018Z021)。
关键词
粉质黏土地层
盾构施工
渣土改良
分散型泡沫剂
silty clay stratum
shield construction
soil conditioning
dispersing foam agent
