絮凝剂对盾构泥浆真空预压效果影响研究

Study on effect of flocculant on vacuum preloading of shield mud

为提高盾构泥浆的脱水减容效果,使用絮凝联合真空预压法对杭州市某盾构工程的盾构泥浆进行试验研究。通过沉积试验研究聚合氯化铝(PAC)、石灰、阴离子聚丙烯酰胺(APAM)、非离子聚丙烯酰胺(NPAM)以及阳离子聚丙烯酰胺(CPAM)的絮凝效果与最优掺加量。设计室内抽滤试验装置并开展固结压缩试验,研究掺入絮凝剂后使用真空预压法处理盾构泥浆的效果。结果表明:使用PAC、石灰与APAM处理盾构泥浆后,盾构泥浆的脱水效率有了明显的提高,最优絮凝剂配比分别为0.3%PAC、2%石灰和0.2%APAM。其中,APAM对提高泥浆自重沉积脱水的效果最好,石灰可以提高后期真空预压法处理盾构泥浆的效率。

In order to promote the effect of dehydration and volume reduction of shield mud,an experimental study of shield mud in a shield project in Hangzhou is carried out using flocculation combined with the vacuum preloading method.The flocculation effect and the optimum dosage of polyaluminum chloride(PAC),calcium hydroxide(Ca(OH)_(2)),anionic polyacrylamide(APAM),non-ionic polyacrylamide(NPAM)and cationic polyacrylamide(CPAM)are studied by a deposition test.In order to study the effect of shield mud treatment by vacuum preloading method after adding flocculant,an indoor filtration test device is designed and a consolidation compression test is conducted.The experimental results show that the dewatering efficiency of shield mud is significantly improved by PAC,Ca(OH)_(2) and APAM and the dosages of PAC,Ca(OH)_(2) and APAM in the optimal flocculant ratio are 0.3%,2%and 0.2%,respectively.In addition,APAM has a best effect on mud dehydration and Ca(OH)_(2) can accelerate the efficiency of vacuum preloading method for shield mud treatments.