为解决土压盾构在富水粉砂地层掘进过程中存在的刀盘转矩过大、开挖面稳定难以控制及排土困难等问题，提高该地层盾构施工的安全性及稳定性，以无锡地铁3号线富水粉砂地层盾构区间为依托，提出土压盾构浓泥渣土改良技术，并开展土压盾构浓泥渣土改良现场试验，研究掘进过程中开挖面前地层中孔隙水压力、盾构掘进参数及地层沉降的变化规律。结果表明： 1）向开挖面注入4 m3/环泥浆后，能够将渣土的坍落度由原来的7.5 cm提高至14.5 cm，降低盾构闭舱和喷涌风险，且能减小土压、推力及转矩的变化波动； 2）浓泥浆在开挖面形成泥膜效应，可以有效降低掘进过程引起的孔隙水压力，最大可减小20 kPa。掘进完成地层稳定后，与未添加浓泥渣土改良掘进的地层相比，地表沉降值减小26.7%。

In order to solve problems of earth pressure balance(EPB) shield tunneling in waterrich silty sand stratum, i.e. overlarge torque of cutterhead, difficult control of tunnel face stability and difficult mucking, and improve the safety and stability of EPB shield construction, ground conditioning by thick slurry is proposed by taking the shield section of Wuxi Metro Line No.3 in waterrich silty sand stratum for example. The field test is carried out, and the variation rules of pore water pressure, shield tunneling parameters and ground settlement are studied. The study results show that: (1) By injecting thick slurry of 4 m3 per ring into tunnel face, the slump of soil is improved from 7.5 cm to 14.5 cm, the risks of shield soil chamber closing and soil and water gushing can be decreased, and the fluctuation of earth pressure, shield thrust and torque can be reduced effectively. (2) The slurry film on tunnel face can be formed by thick slurry, which can effectively reduce the pore water pressure to a maximum of 20 kPa. The final ground settlement of section injected with thick slurry is reduced by 26.7% comparing to that without thick slurry.