暗挖车站施工中拱部预应力锚杆不同支护方向的地层变形研究

Research on Formation Deformation of Arch Prestressed Anchor in Different Supporting Directions in Underground Excavation Station Construction

传统的暗挖车站施工,洞内多设置临时支撑协助抵抗围岩变形,存在施工工期长、拆除困难、费用高等问题。本文以新建暗挖地铁车站为工程背景,通过数值计算的方法对分部台阶法-预应力锚杆支护的大断面隧道施工的地层变形进行了研究。研究结构表明:车站拱顶沉降是暗挖施工中车站沉降的主要方面,拱部支护完成后车站沉降基本趋于稳定。分部台阶法-拱部预应力锚杆竖向布置的施工方法对地层变形控制更有利,拱部预应力锚杆竖向布置,车站开挖完成后拱顶沉降在7.7 mm;拱部预应力锚杆垂直布置,车站开挖完成后拱顶沉降在10.4 mm,拱部预应力锚杆竖向布置对周边建构筑物的变形控制更有利。研究成果可为类似工程提供借鉴。

In traditional underground station construction,temporary support is set up in the hole to help resist the deformation of surrounding rock,which has many problems such as long construction period,difficult demolition and high cost.Based on the background of new underground subway station,this paper studies the formation deformation of large section tunnel construction with partial step method and prestressed bolt support by numerical calculation.The research structure shows that the arch roof settlement is the main aspect of station settlement in excavation construction,and the station settlement tends to be stable after the arch support is completed.The construction method of partial step method and vertical layout of prestressed anchor at arch is more favorable to the formation deformation control.The vertical layout of prestressed anchor at arch is more favorable,and the arch roof settlement is 7.7 mm after the station excavation.The vertical arrangement of prestressed anchor in the arch is more beneficial to the deformation control of surrounding structures,and the arch roof settlement is 10.4 mm after the station excavation is completed.The research results can provide reference for similar projects.