大口径三维曲线顶管顶力估算及实测分析

顶管顶进阻力由顶管机的迎面阻力和管节与土体间的摩阻力两部分组成，现有的顶力估算公式都具有一定的适用条件，虽然物理意义明确，但参数取值范围较大，往往估算顶力与实际工程顶力的匹配程度较低，尤其是在三维曲线顶管工程中受曲线段的影响，准确估算顶力的难度更大。以长413.0 m，外径为3.8 m，最小曲率半径为313.7 m的三维曲线顶管工程为研究对象，基于现有的顶力公式估算所需顶力大小并布设中继间，在该工程实测数据的基础上分析顶力组成及其与顶程、顶进曲率半径等影响因素之间的关系和顶管在平面曲线和垂直剖面曲线以不同曲率半径顶进的摩阻力变化规律。分析结果显示，曲线顶管摩阻力附加系数是真实存在的，且工程实测值与经验值有所偏差，但顶管在淤泥或黏土层中顶进时的摩阻力按规程推荐取值能够满足工程实践需求。最后提出了顶力估算及中继间的布置建议，为类似工程提供依据。

Jacking force estimation and measured data analysis of 3D curved long distance and large diameter pipe jacking

This paper presents the estimation and measured data analysis of the jacking force of a 3D curved pipe with 3.8 meter external diameter and 413 meter long distance. The jacking force consists of the face load and friction resistance; and it is influenced by many factors. The most widely used estimation methods of the jacking force include Chinese cord method; Japanese method and German method; but they all have specific application conditions, which make them have limitations for engineering application; especially when the friction resistance factors are offered by a wide interval. The jacking force are calculated by the above estimation methods in a 3D curved, 413 meter long distance and 3.8 meter external diameter jacking project, 3 intermediate jacking stations are set according to the calculation results. According to the site measuring data during the construction procedure, the composition of the jacking load and its relationship with the jacking distances and the curve radius are analyzed; and the site measured values of frictional coefficient are offer in table. Base on the analysis results, additional frictional coefficient of axis curve pipe jacking is truly exist, and there are deviations between the cord recommended values and the site measured values. but according to this project, the cord recommended values could meet the demands of scheme design in clay or in silt clay. At the end of this paper, suggestions of the jacking force estimation and intermediate jacking station arrangement are proposed, which provide references for similar construction.