降雨对浅埋黄土隧道围岩沉降变形影响研究

为了研究浅埋黄土隧道围岩在降雨工况下的沉降变形机理,依托在建银西铁路沿线董志塬区浅埋长段落大断面驿马隧道,基于现场监测数据,对浅埋长段落黄土隧道雨季施工过程中围岩变形量与降雨量的相关性进行了分析,对浅埋黄土隧道围岩和地表沉降变形特征等进行了分析。结果表明:降雨量对地表变形和围岩变形的发展具有一定的“前瞻性”和“预兆性”。降雨是外在原因,黄土的湿陷性、水敏性、结构性等自身特征是雨季地表变形和围岩变形量明显加剧的内在原因。对浅埋黄土隧道雨季施工时,应针对性地加强地表防排水措施,并采取适当加强隧道初期支护强度与刚度的措施。

Research on the Characteristics of Steel Arch Stresses and Variation of Water Content of Surrounding Rock of Loess Tunnel

In order to research the settlement deformation mechanism of surrounding rock of shallow buried loess tunnel under rainfall condition, relying on the large section Yima tunnel in the shallow buried long section of Dongzhiyuan area along the Yinxi railway under construction, the correlation between the surrounding rock deformation and rainfall during the rainy season construction of the shallow buried long section loess tunnel is analyzed based on the field monitoring data, and the surrounding rock and surface subsidence deformation characteristics of the shallow buried loess tunnel are analyzed. The results show that rainfall has a certain “forward-looking” and “precursory” for the development of surface deformation and surrounding rock deformation. Rainfall is the external reason, and the collapsibility, water sensitivity and structural characteristics of loess are the internal reasons for the obvious increase of surface deformation and surrounding rock deformation inrainy season. For the construction of shallow buried loess tunnel in rainy season, we should strengthen the surface waterproof and drainage measures and take appropriate measures to strengthen the initial support strength and stiffness of the tunnel.