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顶进力是顶管工程中管道结构设计、顶管机选型和工作井结构设计的决定性参数之一。为了更加准确地计算顶进力,假设泥浆压力作用下孔壁保持稳定,管道与孔壁土体发生部分接触,采用协调表面Persson接触模型分析管土接触角度和接触压力分布规律,在此基础上考虑管浆摩阻力影响推导出相应的顶进力计算公式。结果表明:管土接触角度和接触压力分布受管道和地层力学参数影响,软土层中管土接触角度可近似取180°定值,接触压力合力约为管道自重的1.35倍;当管道与岩层力学性质接近时,管土接触趋于点接触状态,接触压力的合力为管道自重,且工程实测顶进力与公式预测值相一致,证明其具有适用性。
Jacking is one of the decisive parameters of pipe jacking design, pipe jacking machine selection and working well structure design. In order to calculate the heading force more accurately, assuming that the pore wall is stable under the action of the mud pressure, the contact between the pipe and the hole-wall soil body is partial, and the Persson contact model is used to analyze the pipe-soil contact angle and the contact pressure distribution law Considering the influence of slurry friction, the corresponding formula of heading force is deduced. The results show that the contact angles of pipe and soil and the distribution of contact pressure are affected by the mechanical parameters of pipelines and stratum. The contact angles of pipe and soil in soft soil can be approximately 180 °, and the resultant of contact pressure is about 1.35 times of that of pipe. When the mechanical properties are close, the contact between pipe and soil tends to be in point contact, and the resultant force of contact pressure is the weight of the pipe. The predicted jacking force of the project is consistent with the predicted value of the formula, which proves that it has applicability.