摘要
为解决在建西延高铁洛川隧道长大距离穿软塑黄土层施工中存在的问题,进行围岩变形数值模拟分析,建立三台阶预留核心土法施工模型,软塑黄土层分布在拱顶、边墙、拱底时,不同层厚(1、3、5 m)对拱顶下沉及拱腰收敛变形产生影响,结合监控量测数据提出合理的变形控制措施。研究结果表明:(1)对软塑黄土层不同分布以及不同厚度工况下围岩位移进行对比,发现软塑黄土层的存在增大了围岩位移,软塑黄土层分布较其厚度影响更明显,当软塑黄土层位于隧道拱顶上方且厚度为5 m时,影响最大。(2)浅埋软塑黄土隧道在超前管棚作用下,围岩竖向位移与水平位移相较于无管棚超前支护时位移减小,在穿软塑黄土层施工时要及时做好防护。(3)拱顶下沉及拱腰收敛随开挖均呈断崖式急剧变形、持续缓慢变形和变形趋于平稳3个阶段。因此,实际施工时应及时开展开挖初期急剧变形阶段的变形控制,并加强围岩监控量测。
To solve the problems existing in the construction of Luochuan Tunnel on Xi'an-Yan'an HSR under construction with long distance passing through soft plastic loess layer,this paper numerically simulates and analyzes the surrounding rock deformation,and establishes a construction model by three-bench method with core soil reserved.When the soft plastic loess layer is distributed on arch crown,side wall and arch bottom,different layer thicknesses(1,3 and 5 m)have an impact on arch crown settlement and horizontal convergence deformation.This paper puts forward reasonable deformation control measures based on monitoring and measurement data.The study results show that:a)By comparing the displacement of surrounding rock under different distribution and thickness conditions of soft plastic loess layer,it is found that the soft plastic loess layer increases the displacement of surrounding rock,and the distribution of soft plastic loess layer has a more significant impact than its thickness.When the soft plastic loess layer is located above the tunnel arch crown with a thickness of 5 m,the impact is the greatest.b)Under the action of advanced pipe shed,the vertical displacement and horizontal displacement of surrounding rock in the shallow-buried soft plastic loess tunnel are reduced compared with those without advanced pipe shed support.Therefore,protection measures shall be taken in time during construction through soft plastic loess layer.c)Arch crown settlement and horizontal convergence around the tunnel display three stages:cliff-like sharp deformation,continuous slow deformation and deformation tending to be stable along with excavation.Therefore,during actual construction,the deformation control of sharp deformation stage in the early stage of excavation shall be carried out in time,and the monitoring and measurement of surrounding rock shall be strengthened.
作者
姜函
郭光旭
贾伟
邓斌
高松
JIANG Han;GUO Guangxu;JIA Wei;DENG Bin;GAO Song(China Railway 20th Bureau Group Co.,Ltd.,Xi’an Shaanxi 710000,China;Xi’an-Chengdu Railway Passenger Dedicated Line Shaanxi Co.,Ltd.,Xi’an Shaanxi 710000,China;Shijiazhuang Tiedao University,Shijiazhuang Hebei 050043,China)
出处
《铁路技术创新》
2024年第1期49-58,共10页
Railway Technical Innovation
关键词
西延高铁
软塑黄土
黄土层分布
黄土层厚度
管棚
黄土隧道
围岩变形
洛川隧道
Xi’an-Yan’an HSR
soft plastic loess
loess layer distribution
loess layer thickness
pipe shed
loess tunnel
surrounding rock deformation
Luochuan Tunnel
