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Discussion of a Theoretical Formula for the Friction Resistance of a Pipe Wall in Quasi-Rectangular Pipe Jacking
(1 School of Civil Engineering, Central South University, Changsha 410075;2 Fujian Province Transmission and Transformation Engineering Co. Ltd., Fuzhou 350013)
Abstract The jacking force is composed of the head resistance and friction resistance of the pipe wall, and the former is generally considered a constant value and the latter increases with an increase of jacking distance. The existing formula for calculating friction resistance of the pipe wall of a rectangular jacking pipe is analyzed, and it is found that the quasi-rectangle is simplified and the pressure arch effect is not considered under deep depth conditions in the existing theoretical formulas, which results in great differences between the calculation values and the measured values. The earth pillar theory and the M. M. Promojiyfakonov pressure arch theory are adopted to deduce a theoretical formula for calculating the friction resistance of the pipe wall of shallow-buried and deep-buried quasi-rectangular jacking pipes. Based on the case study, the friction resistance of the pipe wall calculated by the for? mula given in the specification is relatively conservative when the pipe-jacking tunnel is located in favorable stratum and has a large overburden with the forming of a pressure arch, while the results calculated by the formula proposed in this paper are more reasonable.
Abstract：
The jacking force is composed of the head resistance and friction resistance of the pipe wall, and the former is generally considered a constant value and the latter increases with an increase of jacking distance. The existing formula for calculating friction resistance of the pipe wall of a rectangular jacking pipe is analyzed, and it is found that the quasi-rectangle is simplified and the pressure arch effect is not considered under deep depth conditions in the existing theoretical formulas, which results in great differences between the calculation values and the measured values. The earth pillar theory and the M. M. Promojiyfakonov pressure arch theory are adopted to deduce a theoretical formula for calculating the friction resistance of the pipe wall of shallow-buried and deep-buried quasi-rectangular jacking pipes. Based on the case study, the friction resistance of the pipe wall calculated by the for? mula given in the specification is relatively conservative when the pipe-jacking tunnel is located in favorable stratum and has a large overburden with the forming of a pressure arch, while the results calculated by the formula proposed in this paper are more reasonable.
.Discussion of a Theoretical Formula for the Friction Resistance of a Pipe Wall in Quasi-Rectangular Pipe Jacking[J] MODERN TUNNELLING TECHNOLOGY, 2017,V54(4): 180-185
2017, Vol. 54 