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On Discrimination Method and Treatment Measures for Overall Soil-carrying Effect of Shallow-buried Rectangular Pipe Jacking Projects
(1. Shanghai Road and Bridge (Group) Co., Ltd., Shanghai 200433; 2. College of Civil Engineering, Tongji University, Shanghai 200092; 3. Key Laboratory of Geotechnical and Subsurface Engineering of the Ministry of Education, Tongji University,Shanghai 200092
Abstract Friction exists between shallow-buried rectangular pipe jacking machine, pipes and soils, and when the machine has no drag reduction or anti-soil-carrying device, the substantial friction between the machine and soils will induce an overall soil-carrying effect. This paper introduces a discrimination method of overall soil-carrying effect considering the friction difference between machine (pipe) and soils. Taking the test section of the rectangular pipe jacking project between Luxiang Road and Qilianshan Road in Shanghai as the background, it carries out an analysis of the overall soil-carrying effect based on measured data, and introduces the relevant treatment measures.The results show that the method has successfully predicted the overall soil-carrying failure occurring in the test section, where the calculated critical machine (pipe)-soil friction coefficient is 0.35, the predicted maximum jacking path at the time of failure is 31.05 m (actually 34 m), and the lateral influence range of the overall soil-carrying effect occurring in the pipe jacking is approximately equal to the sum of the overburden depth and the equivalent radius of the section. Also, the influence range of heaving is about 3.0L (L is the head length), and the ground deformation shifts from heaving to settlement when the working face passes through 3.0L
Abstract：
Friction exists between shallow-buried rectangular pipe jacking machine, pipes and soils, and when the machine has no drag reduction or anti-soil-carrying device, the substantial friction between the machine and soils will induce an overall soil-carrying effect. This paper introduces a discrimination method of overall soil-carrying effect considering the friction difference between machine (pipe) and soils. Taking the test section of the rectangular pipe jacking project between Luxiang Road and Qilianshan Road in Shanghai as the background, it carries out an analysis of the overall soil-carrying effect based on measured data, and introduces the relevant treatment measures.The results show that the method has successfully predicted the overall soil-carrying failure occurring in the test section, where the calculated critical machine (pipe)-soil friction coefficient is 0.35, the predicted maximum jacking path at the time of failure is 31.05 m (actually 34 m), and the lateral influence range of the overall soil-carrying effect occurring in the pipe jacking is approximately equal to the sum of the overburden depth and the equivalent radius of the section. Also, the influence range of heaving is about 3.0L (L is the head length), and the ground deformation shifts from heaving to settlement when the working face passes through 3.0L
2022, Vol. 59 