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Superposition Principle Based Numerical Estimation Method of Jacking Force of Vertical Curved Jacking Pipes with Large Rectangular Section
(1 Xingfa School of Mining Engineering, Wuhan Institute of Technology, Wuhan 430074; 2 School of Civil Engineering and Architecture, Wuhan Institute of Technology, Wuhan 430074; 3 School of Civil Engineering, Central South University, Changsha 410075)
Abstract The jacking pipes are divided into several sections according to the slopes of vertical curved jacking pipes with large rectangular section. Based on the displacement control method, the finite element analysis model is established for each section, and the mechanical relationship among the models is set up by setting the initial boundary conditions. The stress field of jacking pipes and surrounding rocks is obtained by applying a displacement value as a pipe length to the initial section of pipe jacking at different jacking positions, and then the jacking force and lateral resistance at each jacking position in each model are calculated. The jacking force and lateral resistance calculated as per the corresponding numerical models are properly superimposed to obtain the fitting relationship between the jacking force and the jacking distance in the whole vertical curved pipe jacking. The calculation results show that the lateral friction coefficient and pipe-soil contact range during shallow pipe jacking are closely related to the properties of the soil layer. In the sandy soil layer, the resistance-reducing slurry is easy to leak and it is diffi? cult to form a stable mud screen around jacking pipes. In this context, the pipes are usually in full contact with soils,of which the lateral friction coefficient can reach 0.4. The fitting formula regarding the relationship between the jack?ing force and the jacking distance obtained under this calculation condition can be used as the general formula for calculating the jacking force of shallow-buried vertical-curved rectangular pipe jacking under the same construction conditions.
Abstract：
The jacking pipes are divided into several sections according to the slopes of vertical curved jacking pipes with large rectangular section. Based on the displacement control method, the finite element analysis model is established for each section, and the mechanical relationship among the models is set up by setting the initial boundary conditions. The stress field of jacking pipes and surrounding rocks is obtained by applying a displacement value as a pipe length to the initial section of pipe jacking at different jacking positions, and then the jacking force and lateral resistance at each jacking position in each model are calculated. The jacking force and lateral resistance calculated as per the corresponding numerical models are properly superimposed to obtain the fitting relationship between the jacking force and the jacking distance in the whole vertical curved pipe jacking. The calculation results show that the lateral friction coefficient and pipe-soil contact range during shallow pipe jacking are closely related to the properties of the soil layer. In the sandy soil layer, the resistance-reducing slurry is easy to leak and it is diffi? cult to form a stable mud screen around jacking pipes. In this context, the pipes are usually in full contact with soils,of which the lateral friction coefficient can reach 0.4. The fitting formula regarding the relationship between the jack?ing force and the jacking distance obtained under this calculation condition can be used as the general formula for calculating the jacking force of shallow-buried vertical-curved rectangular pipe jacking under the same construction conditions.
XIAO Zunqun1,
2,
3 CAO Tongtong1 XU Caiyun1 YANG Kai2 DONG Qiongying1 JIANG Yinan1
.Superposition Principle Based Numerical Estimation Method of Jacking Force of Vertical Curved Jacking Pipes with Large Rectangular Section[J] MODERN TUNNELLING TECHNOLOGY, 2021,V58(6): 68-76
2021, Vol. 58 