盾构隧道同步注浆浆液压力时空分布规律

盾构隧道施工过程中同步注浆浆液压力变化对邻近管片结构内力分布有较大影响，为实现对注浆压力的精细化控制，保证盾构安全掘进，研究浆液压力的时空分布规律.在考虑浆液粘度和地层渗透系数时变性的基础上，统一了同步注浆过程中浆液填充、扩散与消散过程，得到了浆液压力沿管片环向与纵向分布的理论计算式.依托工程实例及浆液流变试验结果，建立数值模型，得到了浆液压力沿管片三维时空分布规律.研究表明：同步注浆过程中浆液固结及注浆压力的衰减对浆液压力分布影响较大.浆液粘度增大，浆液流动性与地层渗透系数逐渐减小，使浆液压力沿管片扩散及消散幅度减小，进而影响管片内力分布.考虑了浆液压力时空变化特性的计算模型使管片受力特征与现场实测结果更加接近.研究成果为精细化分析施工阶段管片受力提供了计算依据.
The variation of synchronous grouting pressure has a significant effect on the internal force distribution of adjacent segments. To control grouting pressure accurately and keep safety during shield driving, the grout pressure distributions in space-time domain were investigated. By considering of time-variation behavior of grout viscosity and permeability, the process of grout filling, diffusion and dissipation during shield backfilled grouting were united. Then, the theoretical formulas of grouting pressure distribution along the circular and longitudinal direction of segments were built. Finally, a grout rheological test and numerical models were conducted based on the engineering case, and the time-space distribution law of grout pressure acting on tunnel segments were obtained and analyzed. The results show that the grout consolidation and pressure dissipation during synchronous grouting have notable influence on distribution of grouting pressure along segments. The increase of grout viscosity and decrease of grout liquidity and permeability of soil layers affect the extent of grouting pressure dissipation, and then affect the distribution of internal force of tunnel segments. The mechanical features of segments calculated from numerical models are closer to field measured data when considering the time-varying effect of grout viscosity. The research results provide a guideline for fine analysis of segment mechanics during construction.