摘要
地铁车站基坑施工建设过程中,基坑土方开挖需要干作业面,基坑降水过程必不可少。在降水井施工完成后,须进行预降水试验来检验能否满足基坑开挖条件及止水帷幕截水效果。但个别建设单位未对此产生足够重视,往往因降水试验所需时间、经济成本,而忽略或放弃筹备进行降水试验,给工程施工埋下一定的安全隐患。基于天津地铁某车站的基坑降水试验数据进行研究分析,发现由于基坑降水井成井施工质量未严格达到要求,造成含水层间相互联通,基坑降水难以满足开挖设计要求。随后,通过采用双液浆注浆加固处理措施封堵隔水层确保其隔水效果,满足基坑降水设计要求的同时,防止了因基坑内疏干降水引发基坑外水位大幅变化对周边环境产生的影响。
During foundation excavation of metro stations,the dry working surface was needed,and dewatering in site is essential.After construction of dewatering wells,the pre-dewatering must be performed to check whether it can meet the excavation condition and the water interception effect for curtain of cutting-off water.However,some construction enterprises do not attach importance to the issues,and often ignore or abandon the preparation for the dewatering test due to considering of time and economic costs,laying a certain potential safety hazard for project construction.Based on data analysis on the dewatering test at the deep excavation site of a metro station in Tianjin,it was found that because the construction quality of dewatering wells did not strictly meet the design requirements,the aquifers were interconnected,and led to the foundation dewatering not to meet the design requirements.Subsequently,a grouting reinforcement measure,which alternately injected water glass and calcium chloride solutions into water-resisting layer,was adopted to block water leakage and ensure its water resisting effect and meet the design requirements of dewatering,and simultaneously prevent the impacts of the significant change in groundwater levels caused by dewatering for deep excavation on the surrounding environment.
作者
雷亚伟
张静涛
田华良
石建成
郑刚
栗晴瀚
程雪松
LEI Yawei;ZHANG Jingtao;TIAN Hualiang;SHI Jiancheng;ZHENG Gang;LI Qinghan;CHENG Xuesong(China Construction Second Engineering Bureau Ltd.,Beijing 100160,China;Department of Civil Engineering,Tianjin University,Tianjin 300350,China)
出处
《工业建筑》
2024年第10期191-198,共8页
Industrial Construction
基金
中国建筑第二工程局有限公司科技资助计划(91110000100024296D200003)
中建股份科技研发计划项目(CSCEC-2021-Z-(25))。
关键词
基坑降水
水位降深
止水帷幕
含水层联通
dewatering for excavation
drawdown
diaphragm wall
connected aquifer
