Study on influence of construction sequence of Pile-Beam-Arch station pilot tunnels on surface settlement

Abstract

Objective During construction of PBA(pile-beam-arch) method stations, land subsidence is greatly affected by the guiding hole excavation sequence. In order to effectively control land subsidence, it is necessary to study the influence law of the guiding hole construction sequence. Method Based on the engineering background of Tiancun Station, a three-dimensional guiding hole construction model for the tunnel of 3-pillar 4-span PBA method station is established, and a reasonable guiding hole excavation sequence is obtained. Based on the above result, in order to shorten the construction period, a staggered synchronous excavation method for the guiding hole construction is proposed, and its effect on land subsidence control is studied based on the on-site measured data. Result & Conclusion The land subsidence is smaller when the lower layer guiding hole is excavated first. When the guiding holes are close to each other, simultaneous excavation will produce group hole effect. In order to effectively control land subsidence in actual construction,separate excavation or staggered excavation should be used.The staggered synchronous excavation method for guiding hole construction has a good effect on land subsidence control,and significantly shortens the construction period. The above method can provide a reference for the similar large-span tunnel station construction.

Keywords

• metro station
• pba method
• guiding hole construction sequence
• land subsidence
• numerical simulation