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顶进力是顶管工程设计和施工的重要参数,而顶管侧摩阻力对顶进力起控制作用,其大小主要受管土接触和管浆接触特性影响。为了更加准确地计算顶管摩阻力,假设隧洞孔壁在泥浆压力作用下保持稳定,管道周围同时存在管土接触和管浆接触,采用协调表面Persson接触模型分析管土接触特性,得出考虑接触压力分布影响的管土摩阻力;然后利用半无限弹性体中柱形圆孔扩张理论分析注浆压力对泥浆套厚度的影响,并结合泥浆触变性和流体力学平行平板模型计算管浆摩阻力。在此基础上考虑管道与隧洞的相对位置,同时将管道顶进时的滑动摩擦阻力作为下限值,顶管重启动时的静摩擦阻力作为上限值,总结出直线和曲线顶管摩阻力公式。通过与工程实例数据对比,结果表明该计算公式下限值与实测值最接近,证明其适用性。
Jacking force is an important parameter of pipe jacking engineering design and construction, and the frictional resistance of jacking pipe plays a controlling role on the jacking force. The size of the jacking pipe is mainly affected by the contacting of pipe and soil and the contacting characteristics of the pipe. In order to calculate the friction resistance of the top pipe more accurately, assuming that the wall of the tunnel is stable under the action of the mud pressure, the pipe-soil contact and the pipe-grout contact exist at the same time around the pipe. The Persson contact model is used to analyze the pipe-soil contact characteristics, Then, the influence of grouting pressure on the thickness of mud jacket is analyzed by using the semi-infinite elastic mid-cylindrical cavity expansion theory. The slurry resistance is calculated with the slurry thixotropy and hydrostatic parallel plate model. On this basis, considering the relative position of pipeline and tunnel, the sliding frictional resistance of pipe jacking is taken as the lower limit value, and the static frictional resistance of jacking pipe as restarting upper limit, the formula of frictional resistance of straight pipe and curved pipe jacking is summarized . By comparing with the data of engineering example, the result shows that the lower limit of this formula is the closest to the measured value, which proves the applicability.