穿越陡坎地形的偏压黄土隧道大变形时空特征研究

针对黄土隧道开挖这一施工领域中的难题,依托地坑院隧道,对隧道穿越沿线地质地形的施工风险进行分析,同时基于监控量测数据,对典型横断面和纵向段的初期支护变形规律进行研究,得出初期支护沿时空分布的变形特征。分析结果表明: 1)围岩变形持续时间长、变形速率大,有时具有突变性; 2)初期支护横断面收敛不均,纵向变形与断面距掌子面距离直接相关; 3)隧道变形受地形、地下水和施工的影响较大。根据现场围岩大变形规律针对性地制定相关控制措施,研究成果可为现场施工提供技术性指导。

Temporal and Spatial Characteristics of Large Deformation of Unsymmetrically-pressured Loess Tunnel Passing through Scarp Terrain

The loess tunnel excavation is always a difficulty in the field of construction. The construction risks of Dikengyuan Tunnel crossing the geological terrain along the line are analyzed, the deformation laws of the primary support of typical cross-sections and longitudinal sections are studied based on the monitoring and measurement data, and the temporal and spatial characteristics of primary support are obtained. The analytical results show that: (1) The surrounding rock deformation is characterized by long duration and high speed, and sometimes with abrupt variation. (2) The cross-section of the primary support is unevenly converged, and the longitudinal deformation is directly related to the distance from the chosen section to the tunnel face. (3) The tunnel deformation is greatly affected by terrain, groundwater and construction. Some relevant control measures are purposed according to the large deformation laws of the surrounding rock on the site. The research results can provide technical guidance for the site construction.