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Research on the Impact of Subway Shield Tunnelling on the Stability of Overcrossing Underpass Foundation Pit
(1 Transportation Institute of Inner Mongolia University, Hohhot 010070; 2 Research Institute of Integrated Transportation Science of Inner Mongolia, Hohhot 010050; 3 Key Laboratory of Road and Traffic Engineering of the Ministry of Education, Tongji University,Shanghai 201804)
Abstract The subway shield tunnelling has a significant impact on the deformation stability and construction safe? ty of the foundation pit of the overpassing underpass. Based on the intersection project between the under-construction underpass and the under-construction Metro Line 2 in Hohhot, this paper studies the impact of subway tunnel shield tunnelling on the stability of overpassing underpass foundation pit through the comparative analysis of numerical simulation and actual measurement and monitoring data. The results show that the retaining wall of the foundation pit is affected by the under-passing construction of the subway tunnel, resulting in settlement and deformation to the inner side of the foundation pit, and the change in the axial force of the steel strut is limited, mainly in the form of settlement, with the accumulative final settlement at about 16 mm under no reinforcement condition; the soil reinforcement under the pit can significantly reduce the deformation of the foundation pit support structure, and in particular, the settlement value can be reduced to 30% of that under no reinforcement condition. The numerical analy? sis by finite element modeling can reflect the general law of the effect of the under-passing subway tunnel construction on the deformation of the foundation pit support structure, which can provide a certain theoretical basis for the design of retaining walls of foundation pits.
Abstract：
The subway shield tunnelling has a significant impact on the deformation stability and construction safe? ty of the foundation pit of the overpassing underpass. Based on the intersection project between the under-construction underpass and the under-construction Metro Line 2 in Hohhot, this paper studies the impact of subway tunnel shield tunnelling on the stability of overpassing underpass foundation pit through the comparative analysis of numerical simulation and actual measurement and monitoring data. The results show that the retaining wall of the foundation pit is affected by the under-passing construction of the subway tunnel, resulting in settlement and deformation to the inner side of the foundation pit, and the change in the axial force of the steel strut is limited, mainly in the form of settlement, with the accumulative final settlement at about 16 mm under no reinforcement condition; the soil reinforcement under the pit can significantly reduce the deformation of the foundation pit support structure, and in particular, the settlement value can be reduced to 30% of that under no reinforcement condition. The numerical analy? sis by finite element modeling can reflect the general law of the effect of the under-passing subway tunnel construction on the deformation of the foundation pit support structure, which can provide a certain theoretical basis for the design of retaining walls of foundation pits.
ZHANG Hong1,
2 LIU Haiyang1,
3
.Research on the Impact of Subway Shield Tunnelling on the Stability of Overcrossing Underpass Foundation Pit[J] MODERN TUNNELLING TECHNOLOGY, 2021,V58(4): 125-132
2021, Vol. 58 