摘要
一般地铁基坑地下连续墙成槽周期约为1 d~2 d,但遇到钙质铰结地层时往往成槽时间会延长至5 d~7 d,严重时会导致槽壁坍塌。为此,依托郑州市轨道交通7号线路砦站基坑工程,通过正交试验对24 h后的浆液性能各项指标和泥浆胶体率的变化规律进行了分析,并对聚丙烯酸钠和膨润土改良后的泥浆7 d后的各项性能指标进行了研究。研究表明:对泥浆比重、黏度、失水量的影响敏感度为:膨润土>CMC>纯碱;而对泥浆泥皮厚度的影响敏感度为:膨润土>纯碱>CMC;泥浆的比重、黏度、泥皮厚度均会随着膨润土的增加而有所提高,但泥浆的失水量随着膨润土的增加而减小;根据试验结果并结合泥浆性能指标要求,得到适合本工程的泥浆配比为:膨润土60 g、CMC2.0 g、纯碱6.0 g、聚丙烯酸钠1.0 g。
The excavation period of the underground continuous wall in a general subway foundation pit is about 1~2 days,but when encountering calcareous hinge formations,the excavation time often extends to 5~7 days,and in severe cases,it can lead to the collapse of the excavation wall.Therefore,based on the foundation pit project of Zhengzhou Metro Line 7 Lu Zhai Station,the performance indicators of the slurry after 24 hours were analyzed through orthogonal experiments and the variation pattern of the slurry colloid ratio.The performance indicators of the slurry improved with sodium polyacrylate and bentonite after 7 days were also studied.The research shows that the sensitivity to the influence of mud specific gravity,viscosity,and water loss is as follows:bentonite>CMC>soda ash;The sensitivity of the influence on the thickness of the mud skin is as follows:bentonite>soda ash>CMC;The specific gravity,viscosity,and mud skin thickness of the mud will increase with the increase of bentonite,but the water loss of the mud will decrease with the increase of bentonite;Based on the test results and combined with the requirements of mud performance indicators,the suitable mud ratio for this project is:60 g bentonite,2.0 g CMC,6.0 g soda ash,and 1.0 g sodium polyacrylate.
作者
胡昌建
蔡云鹏
康祖玮
吴涛
李明宇
Hu Changjian;Cai Yunpeng;Kang Zuwei;Wu Tao;Li Mingyu(Urban rail transit engineering branch of China Railway fourth Bureau Group Co.,Ltd.,Hefei 230022,P.R.China;School of Civil Engineering,Zhengzhou University,Zhengzhou 450001,P.R.China)
出处
《地下空间与工程学报》
CSCD
北大核心
2023年第S02期740-750,共11页
Chinese Journal of Underground Space and Engineering
基金
国家重点研发计划资助(2017YFC1502600)
河南省住房城乡建设科技计划项目(K-1818)
关键词
基坑工程
地下连续墙
钙质胶结地层
泥浆护壁
长效特性
foundation pit works
underground diaphragm wall
calcareous cemented formation
mud wall protection
long term characteristics
