摘要
上海某挖深达4545m的隧道工作井超深基坑工程涉及复杂的多层承压含水层减压降水,且周边邻近磁悬浮等重点保护对象。为避免基坑侧向渗漏和基底突涌风险,并控制抽降深部承压水对周边环境的影响,于超深地下连续墙围护墙的外侧设置厚09m、深69m的TRD工法等厚度水泥土搅拌墙形成双帷幕体系。如此深度的TRD工法实施尚无先例可循,故于正式施工前采用新型TRD-80E工法机,开展了86m深的TRD工法成墙试验,确定其施工能力、施工工效及施工参数。试成墙为后续69m深TRD工法正式成墙的顺利实施提供了依据,正式成墙墙体质量检测和周边环境监测结果表明,墙体的强度、渗透性均满足设计要求,且环境影响较小。在基坑开挖前开展了双帷幕间的试抽水试验,结果表明TRD工法隔水帷幕内外水位降深比约300∶1,停抽后水位恢复极缓慢,进一步验证了TRD工法超深隔水帷幕良好的隔水效果。
A 455m deep excavation project in Shanghai involved dewatering of complex multi-layer confined aquifers and protection of the adjacent maglev facilities.In order to avoid the risk of lateral leakage and upheaval and to control the impact of pumping and lowering of the confined water on the surrounding environment,double waterproof curtains were adopted.Thus,a constant thickness cement-soil wall with thickness of 09m and depth of 69m was set up on the outside of the retaining diaphragm wall.Since there was no precedent for the implementation of such an ultra-deep TRD,the new TRD-80E construction machine was used before the formal construction to carry out an 86m-deep TRD trial wall test to determine its construction capacity,construction efficiency and construction parameters.The results of the trial wall test provided a guidance for the smooth implementation of the subsequent 69m-deep TRD formal wall practice.The results of wall quality inspection and surrounding environment monitoring showed that the strength and permeability of the formal wall could meet the design requirements,and the environmental impact was small.Before soil excavation,a pumping test between the double waterproof curtains was carried out.The ratio of confined groundwater drawdown inside and outside the TRD was about 300:1,and the water level recovered very slowly after the pumping was stopped.These results verified the good water barrier effect of the TRD wall.
作者
宗露丹
张佶
徐中华
潘伟强
ZONG Ludan;ZHANG Ji;XU Zhonghua;PAN Weiqiang(Shanghai Underground Space Engineering Design&Research Institute,East China Architecture Design&Research Institute Co.,Ltd.,Shanghai 200011,China;Shanghai Engineering Research Center of Safety Control for Facilities Adjacent to Deep Excavations,Shanghai 200011,China;Shanghai Tunnel Engineering Construction Co.,Ltd.,Shanghai 200002,China)
出处
《施工技术（中英文）》
CAS
2023年第19期10-16,共7页
Construction Technology
基金
上海市科委重点攻关项目(21DZ1204203)
上海市青年科技英才扬帆计划(22YF1409600)。
关键词
深基坑
水泥土搅拌墙
隔水帷幕
承压水
试验
deep foundation excavation
cement-soil wall
waterproof curtain
aquifer
tests
