顶管侧摩阻力理论公式的探讨

Discussion on theoretical formulae of lateral friction resistance for pipe-jacking

顶管顶力是由迎面阻力和侧摩阻力组成的,影响顶力的因素很多。分析已有摩阻力计算公式后,给出了圆形断面和方形断面管节的摩阻力计算结果不同的原因。现有的摩阻力计算公式存在一些问题,对于土质较好和埋深够大,能够形成压力拱时的摩阻力计算不合理,在实际工程中,摩阻力并不是随埋深无限增加的。从压力拱理论出发,求出管节外壁土压力的分布,对侧摩阻力计算公式稍作改进。通过算例比较,能形成压力拱时,按照本文公式计算的结果比较合理。

The jacking force consists of the face pressure and friction resistance. It is influenced by many factors. After analyzing the existing formulas, the reasons of the different results, which are calculated from circle pipe and the rectangular pipe, are found. The existing calculation formulas of frictional resistance have some problems. When the soil is well and the depth of embedment is enough, a pressure arch will be formed; therefore the existing formulas are unreasonable to calculate the frictional resistance. In the real engineering, the friction resistance does not increase by the depth of embedment illimitably. From the theory of pressure arch, getting the distribution of soil pressure, to improve the calculation formulas of frictional resistance a little. Through the comparison of example, when the pressure arch will be formed, the result which is calculated by the formulas of this article is more reasonable.