Based on laboratory and field tests for a cross-river highway shield tunnel in China, the causes of ground collapse by shield tunnelling in a water-rich fine sand stratum were analyzed. To ensure the safety of subsequent shield tunnelling, reinforcement treatment was carried out, and then the reinforcement effect was comprehensively evaluated. The results showed that the fine sand properties, slurry circulation quality, support pressure set and excess pore water pressure fluctuation are the main reasons for the collapse of sandy ground. The comparative analysis of the permeability coefficient of the stratum and tunnelling parameters of the shield indicated that the grouting reinforcement effect on the fine sand stratum was obvious and that the disturbance to the stratum can be effectively controlled.

根据我国跨河公路盾构隧道的实验室和现场试验，分析了富水细砂地层中盾构施工引起地面塌陷的原因。为确保后续盾构施工的安全性，进行了加固处理，然后对加固效果进行了综合评估。结果表明，细砂性，泥浆循环质量，支护压力设定和过大的孔隙水压力波动是造成砂土塌陷的主要原因。通过对地层渗透系数和盾构掘进参数的对比分析，表明对细砂地层的注浆加固效果明显，可以有效地控制对地层的扰动。