越江泥水盾构隧道泥浆改性及泥膜渗透性状试验研究  

Investigation on slurry modification and filter cake permeabilities in slurry shield of river-crossing tunnel

作　　者：张赛 焦宁 丁建文[1] 孙帅 刘晋余 Zhang Sai;Jiao Ning;Ding Jianwen;Sun Shuai;Liu Jinyu(School of Transportation,Southeast University,Nanjing 211189,China)

机构地区：[1]东南大学交通学院,南京211189

出　　处：《东南大学学报（自然科学版）》2023年第2期286-294,共9页Journal of Southeast University：Natural Science Edition

基　　金：国家自然科学基金资助项目(51978159);国家科技支撑计划资助项目(2015BAB07B06)。

摘　　要：为指导越江泥水盾构隧道施工过程中的泥浆性质动态调节,以羧甲基纤维素钠(CMC)和粉细砂为主要调控材料,对不同配比泥浆进行密度、黏度、胶体率测试,并基于API滤失试验研究各配比泥浆的滤失性状及泥膜的渗透特性.结果表明:钠基膨润土-粉细砂-CMC泥浆体系具有良好的分散性,泥浆胶体率普遍在98%以上;对于生成泥皮+渗透带型的砂砾地层,虽然通过掺加粉细砂可有效堵塞地层,减小滤失量,但其形成的泥膜渗透系数和滤失量则相对较大;对于需要快速在开挖面形成泥皮型泥膜的地层,增加CMC的掺量可以有效减小泥膜形成时的滤失量,降低泥膜渗透系数;但CMC掺量过大后所成泥膜孔隙比增大,结构疏松,渗透系数反而呈增长趋势.施工过程中可结合实际需求对泥浆性质进行动态调整,以保障泥水盾构掘进和开舱安全.To guide the dynamic adjustment of slurry properties during the slurry shield of river-crossing tunnel,the slurry density,viscosity and colloidal fraction were tested with different sodium carboxymethyl cellulose(CMC)and silty sand contents,the filtration characteristics of slurry and permeability of filter cake with different proportions were studied based on American Petroleum Institute(API)fluid test.The results show that the sodium bentonite-silty sand-CMC slurry systems have good dispersion whose colloidal fractions are generally above 98%.As for gravel strata where filter cake and infiltration zone are generated,adding silty sand can effectively block strata and reduce filtration rate,but the permeability coefficient and filtration rate of filter cake are relatively large.As for strata where filter cake needs to be generated rapidly,adding CMC can effectively reduce the filtration rate,and reduce the filter cake permeability coefficient.However,the pore ratio of filter cake increases with CMC content continuously increasing,which makes the filter cake structure become loose and the permeability coefficient increase.During the construction process,the slurry properties can be dynamically adjusted according to the actual requirements to ensure the safety of slurry shield during tunneling and chamber opening.

关 键 词：越江隧道 泥水盾构 改性泥浆 滤失量 泥膜渗透系数 

分 类 号：TU449[建筑科学—岩土工程]