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.