软土地层地下连续墙成槽护壁泥浆研究

含砂性土等软土地层地下连续墙成槽施工，基槽侧壁易扰动坍塌，影响地下连续墙施工质量。降低泥浆失水量、适当提高泥浆粘度和防塌是护壁成槽的关键。结合宁波轨道交通车站基坑地下连续墙成槽施工，采用部分水解聚丙烯酰胺(PHP)、聚丙烯腈钙(CPAN)和硝基腐植酸钾(NKHm)作为添加剂，根据正交试验测定泥浆性能优化配比。研究表明：PHP失水量小，泥皮薄；CPAN和NKHm对降失水量效果明显，粘度适中。将试验结果应用于工程实践，护壁效果好。

Application Research on Properties of Protection Slurry for Diaphragm Retaining Wall Trenching in Soft Soil

For the construction of diaphragm retaining wall trenching in sand-bearing soft soil layer, the construction quality will be affected by the collapse of side wall of trench. Water loss reducing, appropriate slurry viscosity increasing and collapse prevention are the key for wall protection in trenching. According to the geological conditions of a diaphragm retaining wall trenching engineering in Ningbo, partially hydrolyzed polyacrylamide (PHP), calcium polyacrylonitrile (CPAN) and potassium nitryl humate (NKHm) were taken as additives; the optional ratio of slurry performance was ascertained by the orthogonal test. The test results show that when using PHP, the amount of water loss is small with thin mud cake; CPAN and NKHm have evident effects on fluid loss control with moderate viscosity. The test result is applied in the engineering practice and the good effect of wall protection is received.