摘要
对于需要充分利用地层抗力实现联合受力的高压输水盾构隧洞,壁后注浆材料除了满足常规的要求外,还需满足浆液硬化后强度高、体积收缩率小的要求。采用流动性较大的自密实砂浆可满足工程的强度或工作性要求,但往往难以同时满足。特别是强度较高的砂浆,其凝结时间通常不能满足施工要求。选取柠檬酸钠、葡萄糖酸钠、白糖等缓凝型外加剂,研究不同掺量与不同缓凝剂的复配使用对自密实砂浆流动度、稠度、凝结时间的影响。结果表明,柠檬酸钠单独使用能延缓凝结时间,但会降低其流动度;与葡钠复合使用时,能较长延缓凝结时间,对其流动度影响会变小;与白糖掺用,缓凝效果佳,对其流动度影响小,但易离析泌水。在实际工程中,推荐使用柠檬酸钠和葡萄糖酸钠复配作为缓凝型外加剂,从而保证自密实砂浆具有较好的工作性能,当采用柠檬酸钠与白糖复配使用时,应注意掺量不宜过大,从而保证自密实砂浆的稳定性和工作适用性。
For high-pressure water transmission shield tunnel which needs to make full use of stratum resistance to realize joint stress,grouting material behind the wall should not only meet the conventional requirements,but also meet the requirements of high strength and small volume shrinkage after grout hardening.Self-compacting mortar with high fluidity can meet the strength or workability requirements of the project,but it is often difficult to meet them at the same time.Especially for mortar with high strength,its setting time usually cannot meet the construction requirements.Selecting retarding admixtures such as sodium citrate,sodium gluconate and white sugar,this paper studies the effects of different dosages and retarders on fluidity,consistency and setting time of self-compacting mortar.The results show that sodium citrate alone can delay the setting time,but reduce its fluidity.When combined with sodium gluconate,it can delay the coagulation time for a long time,and the influence on its fluidity will become smaller;When mixed with white sugar,the retarding effect is good,and it has little influence on its fluidity,but it is easy to separate and bleed.In practical engineering,it is recommended to use sodium citrate and sodium gluconate as retarding admixture,so as to ensure the good working performance of self-compacting mortar.When sodium citrate and white sugar are used together,attention should be paid to that the dosage should not be too large,so as to ensure the stability and working applicability of self-compacting mortar.
作者
张武
刘微
吕淼
ZHANG Wu;LIU Wei;LYU Miao(Guangdong Hydropower Planning&Design Institute,Guangzhou 510635,China;Chongqing Jiaotong University,Chongqing 400074,China;Tsinghua University State Key Laboratory of Water and Sediment Science and Water Conservancyand Hydropower Engineering,Beijing 100084,China)
出处
《广东水利水电》
2020年第9期9-13,共5页
Guangdong Water Resources and Hydropower
基金
珠江三角洲水资源配置工程科研项目(编号:WW2018225、WW2018231)。
关键词
壁后注浆
自密实砂浆
柠檬酸钠
缓凝剂
凝结时间
grouting behind lining
self-compacting mortar
sodium citrate
retarder
coagulation time
