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Calculation Method for the Passive Limit Support Pressure of an Extra-Large Diameter Slurry Balance Pipe-Jacking Machine in Clay
(1 Key Laboratory for Geotechnical and Underground Engineering of Ministry of Education, Tongji University, Shanghai 200092; 2 Department of Geotechnical Engineering, Tongji University, Shanghai 200092; 3 Shanghai Urban Construction Municipal Engineering Group Co. Ltd., Shanghai 200065)
Abstract Considering that the support pressure of a pipe-jacking machine must be lower than the passive limit support pressure to ensure stability of the working face, this paper proposes a calculation method for the passive limit support pressure of an extra-large diameter slurry balance pipe-jacking machine in clay based on the ultimate equilibrium of the working face. First, the jacking pipe's passive failure model was studied using anumerical simulation, then a relevant calculation concept was established based on the results and finally the method's rationality was preliminarily verified by the numerical simulation of a practical case. Compared with other methods and based on the analysis of its influence factors, it is indicated that:1) the horizontal cylinder failure mode, which is a passive failure mode and independent of buried depth, is appropriate for the slurry jacking pipe; 2) the proposed method is applicable to the practice for its rationality and simple calculations, of which the application condition for the layered and homogeneous clay simply requires that the working face being kept in a single stratum; 3) the method is more conservative than others, with reasonable lower values; and 4) the obtained passive support pressure increases with an increase of the depth-diameter ratio, internal friction angle and cohesion.
Abstract：
Considering that the support pressure of a pipe-jacking machine must be lower than the passive limit support pressure to ensure stability of the working face, this paper proposes a calculation method for the passive limit support pressure of an extra-large diameter slurry balance pipe-jacking machine in clay based on the ultimate equilibrium of the working face. First, the jacking pipe's passive failure model was studied using anumerical simulation, then a relevant calculation concept was established based on the results and finally the method's rationality was preliminarily verified by the numerical simulation of a practical case. Compared with other methods and based on the analysis of its influence factors, it is indicated that:1) the horizontal cylinder failure mode, which is a passive failure mode and independent of buried depth, is appropriate for the slurry jacking pipe; 2) the proposed method is applicable to the practice for its rationality and simple calculations, of which the application condition for the layered and homogeneous clay simply requires that the working face being kept in a single stratum; 3) the method is more conservative than others, with reasonable lower values; and 4) the obtained passive support pressure increases with an increase of the depth-diameter ratio, internal friction angle and cohesion.
ZHOU Shu-Wei-1,
2 ,
XIA Cai-Chu-1 etc
.Calculation Method for the Passive Limit Support Pressure of an Extra-Large Diameter Slurry Balance Pipe-Jacking Machine in Clay[J] MODERN TUNNELLING TECHNOLOGY, 2015,V52(3): 127-136
2015, Vol. 52 