Abstract Taking an underpass project in Hangzhou as an example, this paper introduces some key techniques for
an urban underpass in saturated soft soil constructed by the shallow mining method. For the pre- reinforcement ahead of the tunnel face, the TSS method is characterized by controllable grouting pressure, uniform grout distribution and the reinforcement effect of grouting pipes. For the excavation method, the CRD method with six excavation portions should be adopted for the first excavation of the middle part and then for excavation of the two side parts,but the length of the reserved core soil must be determined considering the effects of the pre-grouting reinforcement and the controlling effects of the foot-locking anchor against side wall deformation. For reducing the risk of removing the temporary support, the longitudinal connection reinforcements should be enhanced and small pipes should be installed in full-face to improve structure rigidity and soil strength, as well as to control ground settlement.
Abstract：
Taking an underpass project in Hangzhou as an example, this paper introduces some key techniques for
an urban underpass in saturated soft soil constructed by the shallow mining method. For the pre- reinforcement ahead of the tunnel face, the TSS method is characterized by controllable grouting pressure, uniform grout distribution and the reinforcement effect of grouting pipes. For the excavation method, the CRD method with six excavation portions should be adopted for the first excavation of the middle part and then for excavation of the two side parts,but the length of the reserved core soil must be determined considering the effects of the pre-grouting reinforcement and the controlling effects of the foot-locking anchor against side wall deformation. For reducing the risk of removing the temporary support, the longitudinal connection reinforcements should be enhanced and small pipes should be installed in full-face to improve structure rigidity and soil strength, as well as to control ground settlement.
.Key Techniques for an Urban Underpass in Saturated Soft Soils Constructed by the Shallow Mining Method[J] MODERN TUNNELLING TECHNOLOGY, 2017,V54(3): 195-199
2017, Vol. 54 