复杂土层环境中大直径钢顶管施工稳定机理与控制

The pipe-jacking method has been an important means to lay underground steel pipelines in the urban area. The load condition gets more complex in construction stage than it in service stage, which is affected by the effect of pipe-soil interaction under the axial compression or the combined loadings. The stability of steel pipe-jacking with great diameter has been a growing severe problem under complicated stratum as the diameter and the length increase. To address the problem on stability and control of steel pipe-jacking under complicated stratum in construction stage, the model test, the numerical analysis and the field test are used to study the mechanism and the analytical method. Introducing the pipe-soil interaction model combined with the finite strip method, the theoretical model of steel pipe-jacking with great diameter under complicated stratum and load conditions is established. Stability analysis method is proposed. Based on the model test and the numerical simulation, the response characteristics of steel pipe-jacking and soil under different strata is investigated. The effect of different parameters of steel pipes, soil and loads is clarified. The stability mechanism of steel pipe-jacking under complicated stratum in construction stage is revealed. Then the stability control and the evaluation method are put forward with analyses on the reinforcement forms of steel pipe-jacking. The study results are of great significance to illustrate the steel pipe-jacking instability accidents and mechanism in construction stage, and provide the theoretic foundation for reinforcement of steel pipe-jacking after buckling.

顶管法敷设钢管已成为城市地下管道建设的重要手段，钢顶管施工的受力变形比管道运营阶段更为复杂：以轴力为主且受复合荷载作用、管土相互作用动态变化。在钢顶管直径和长度不断发展的情况下，复杂土层环境中大直径钢顶管施工稳定性问题日益突出。本项目针对复杂土层环境中大直径钢顶管施工稳定与控制问题，采用模型试验、数值分析和现场测试等方法研究钢顶管稳定机理及分析方法。结合有限条法引入管土相互作用模型，建立考虑复杂土层和荷载工况的大直径钢顶管受力变形理论模型，提出稳定性分析方法；通过模型试验和数值模拟，研究不同土层中钢顶管与土体的响应特征，阐明钢管、土体、荷载等不同参数对钢顶管稳定性的影响规律，揭示复杂土层环境中大直径钢顶管施工稳定响应机理；探讨不同管道加固形式下钢顶管稳定性变化规律，提出稳定控制措施及评估方法。研究成果对于阐明施工阶段钢顶管稳定机理具有重要意义，为钢顶管施工安全控制提供理论基础。

顶管法施工敷设钢管已经成为城市地下管道施工的重要手段，复杂地土层环境中大直径钢 顶管施工稳定性问题日益突出。周围地质条件会影响施工钢顶管的变形稳定性，钢顶管的变形失稳又会造成地层的变形破坏，管土相互作用效应导致施工阶段钢顶管稳定性分析更为困难。本项目针对复杂土层环境中大直径钢顶管施工稳定机理与控制问题，采用了理论研究、模型试验、数值分析和现场测试等方法研究以轴力为主且受复合荷载作用的钢顶管变形稳定机理及分析方法。提出了基于环向受力条件下轴对称极限平衡理论，确定了钢顶管施工时的受力状态；提出了基于剪切变形板理论和弹性地基的有限条分析方法，揭示了管土相互作用影响下钢顶管的受力变形和屈曲失稳机理；应用有限条分法和有限元法，分析了以及不同加固形式对钢顶管的稳定性影响规律；监测了钢顶管施工阶段管周水土响应和地面沉降，结合监测数据探讨了温度变化和顶管转角对大直径钢顶管力学特性和稳定性的影响，建立了增强施工阶段钢顶管稳定性的加固方式。揭示复杂土层环境中大直径钢顶管施工稳定响应机理，最终应用于实际工程。相关研究成果发表论文51篇，其中SCI检索论文36篇，EI论文6篇，中文核心检索9篇，培养硕博士生6名。研究成果对于阐明施工阶段钢顶管稳定控制机理具有重要意义，为钢顶管失稳后加固措施研究提供理论基础。