高水压粉细砂地层泥水钢顶管泥浆套二次注浆压力影响分析

Pressure Effects of Secondary Annular Grouting on Slurry Shield Steel Pipe Jacking in High-Water-Pressure Silty Fine Sand Strata

摘要: 为研究高水压粉细砂地层泥浆套二次注浆对钢顶管的影响，依托云南省某超前引排水顶管工程，基于半球形扩散理论建立了泥浆套二次注浆浆液扩散模型与考虑二次注浆压力的管道受力模型，通过数值模拟系统分析了钢管道在不同围压、不同注浆压力与注浆方式下管道变形与应力分布规律，共得到以下结论：1) 增大注浆压力与延长注浆时间均能提高浆液扩散效果，起到更好的注浆作用，但前者会显著提高管道压力，建议工程中注浆时间控制在浆液初凝时间的50%~70%，以兼顾注浆质量与施工冗余；2) 考虑二次注浆压力时，注浆孔附近变形与应力较大可能有局部失稳的风险，当注浆压力较大时应进行附加结构验算，并建议采取局部增厚或加劲肋等加强措施。3) 当顶管穿越不同富水地层时，弱富水区管节在高注浆压力下的局部稳定性可能成为工程控制条件，同时应尽量避免双侧长时间注浆。本研究成果可为后续类似工程提供参考。

Abstract: To study the influence of secondary grouting of the slurry sleeve on steel pipe jacking in high water pressure silty sand strata, a slurry diffusion model and a pipe mechanical model considering secondary grouting pressure were established based on the hemispherical diffusion theory, relying on an advance drainage pipe jacking project in Yunnan Province. The deformation and stress distribution laws of steel pipes under different confining pressures, grouting pressures, and grouting methods were systematically analyzed through numerical simulation. The main conclusions are as follows: 1) Increasing both grouting pressure and duration can improve the slurry diffusion effect and enhance grouting performance. However, the former significantly increases pipe pressure. It is suggested that the grouting duration in engineering practice be controlled within 50% to 70% of the initial setting time of the slurry to balance grouting quality and construction redundancy; 2) When considering secondary grouting pressure, the deformation and stress near the grouting hole are relatively large, posing a risk of local instability. When the grouting pressure is high, supplementary structural verification should be performed, and reinforcement measures such as localized thickening or stiffening ribs are recommended. 3) When pipe jacking traverses different water-bearing strata, the local stability of pipe segments in weakly water-rich areas under high grouting pressure may become the engineering control condition. Meanwhile, prolonged simultaneous grouting on both sides should be avoided. The research results can provide a reference for similar future projects.