浅埋暗挖交叉相贯隧道施工力学行为试验研究

Experimental study on construction mechanical behavior of shallow-buried concealed intersecting tunnel

为完善浅埋暗挖交叉相贯隧道在施工过程中的受力形式及变形特征,依托青岛某地铁工程,根据所选地铁车站的地质条件及衬砌结构特点浇筑衬砌模型并配制围岩相似材料,利用模型试验对采用全断面法在Ⅴ级围岩环境下进行的风道和车站主体开挖过程的力学行为展开研究,并从隧道衬砌结构变形及地层内部位移变化规律两方面分析了浅埋暗挖交叉相贯隧道全断面开挖施工的力学行为。结果表明:对于交叉相贯位置处的隧道结构,已有隧道结构将改变后续施工隧道衬砌结构应变最大值及其出现位置;位于交叉相贯隧道结构附近不同象限内的围岩分别处于水平变形累加区和往复区;地表竖向变形最大点位于后续施工的车站上方且与交叉相贯位置存在一定距离,而在交叉相贯位置处的地表竖向变形值稍小;模型试验明确了交叉相贯隧道在施工过程中围岩及衬砌结构的变形特征,给出了隧道结构地表最大变形与施工步序间的时空关系;研究结果可为相关交叉相贯隧道结构的施工及设计提供依据。

In order to improve the stress form and deformation characteristics of the shallow-buried concealed intersecting tunnel during the construction process,based on a subway project in Qingdao,the lining model was poured according to the geological conditions of the selected subway station and the characteristics of the lining structure,and the similar materials of the surrounding rock were prepared.The model test was used to study the mechanical behavior of the air duct and the main body of the station during the excavation process using the full-section method in the grade-Ⅴsurrounding rock environment.The mechanical behavior of the full-section excavation of the shallow-buried concealed intersecting tunnel was analyzed from two aspects:the deformation of the tunnel lining structure and the internal displacement of the stratum.The results show that for the tunnel structure at the intersecting position,the existing tunnel structure will change the maximum strain and its position of the lining structure of the subsequent construction tunnel.The surrounding rock in different quadrants near the cross-intersecting tunnel structure is in the horizontal deformation accumulation zone and the reciprocating zone respectively.The maximum vertical deformation point of the surface is located above the station of the subsequent construction and has a certain distance from the intersection position,while the vertical deformation value of the surface at the intersection position is slightly smaller.The model test clarifies the deformation characteristics of the surrounding rock and lining structure during the construction of the intersecting tunnel,and gives the temporal and spatial relationship between the maximum surface deformation of the tunnel structure and the construction sequence.The research results can provide a basis for the construction and design of related intersecting tunnel structures.