通过模型试验，对泥浆盾构施工中泥浆维持开挖面稳定的力学机理，开挖面前缘土体的应力变化规律，泥浆压力作用机理及泥皮形态进行了研究，提出了中粗砂地基中临界泥浆压力 公式。

 Through model test, a research is carried out on the mechanism of the stability of excavated surface of tunnel sustained by slurry during construction by the slurry shield method,on the regularity of stress variation in the soil mass in the front of excavating surface and on the mechanism of action of slurry pressure and the formation of slurry membrane.The formula of the critical slurry pressure suitable for the medium and coarse sand foundation is presented.