Analysis of Settlement and Deformation Law of Subgrade Section for Multi-arch Tunnel with the Pipe Roof Method Underpassing Expressway
Relying on the tunnel project of a certain underpass highway ramp foundation section,this paper briefly introduces the design and construction scheme of multi arch tunnel of the pipe roof method.A numerical model is established to simulate the settlement and deformation law of subgrade section of expressway through multi arch tunnel of the pipe roof method and the settlement deformation curve of subgrade section is obtained.The settlement and deformation rule of the subgrade section of the underpass expressway is analyzed by comparing with the field monitoring and measurement data.The results show that:1)The deformation law curve of roadbed settlement formed by connecting various monitoring points is a"U"shaped curve and the large settlement values are distributed within the intersection area of tunnels and ramps.2)The settlement deformation value of the roadbed gradually increases with tunnel excavation and the settlement deformation rate of the ramp located in the intersection area of the tunnel and ramp is the highest,and the further away from the tunnel,the smaller the settlement deformation rate of the ramp.3)The smaller the angle between the tunnel and the ramp,the larger the corresponding impact range of roadbed settlement.4)According to simulation calculations and numerical analysis of measured ramp settlement,it is obtained that settlement value caused by multi-arch tunnel through the ramp roadbed by pipe roof method does not exceed 10 mm.The impact on highways is relatively small,and settlement is effectively controlled.
the pipe roof methodmulti-arch tunnelsettlement deformationunderpass expressway
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