浅埋大跨小间距黄土隧道支护技术研究

以武-西高速公路桃花峪黄土隧道为研究对象，采用现场试验与数值模拟的方法，研究格栅和型钢支护结构对浅埋大跨小间距黄土隧道的影响规律。现场试验表明，施工引起的沉降比较均匀，格栅支护与型钢支护对控制整体沉降差别不明显。格栅钢架的受力比型钢钢架小且分布更为均匀，说明格栅钢架受力更为有利。格栅与型钢钢架受力状态相似且都合理。模拟计算表明，格栅支护与型钢支护相比，型钢支护的位移更小。较之格栅，型钢支护拱顶沉降减小16%~18%，边墙收敛减小23%，拱脚沉降减小18%。在V级黄土隧道中采用双侧壁法开挖大断面隧道，围岩将发生较大塑性变形。塑性区域发展范围较大，需及时支护，格栅支护与型钢支护对塑性发展范围基本一致。

Supporting technology for shallow large-span neighborhood loess tunnel

With the Taohuayu loess tunnel of Wu-Xi expressway as the research object, it use field experiment and numerical simulation methods to research the influence laws of grating supporting and section steel supporting on shallow large-span neighborhood loess tunnel. The field experiment shows that the settlement caused by construction is uniform, and the control overall settlement ability by grating supporting and section steel supporting are similar. The stress of grating is smaller than section steel; and the stress distribution of grating is more uniform than section steel. The stress state of grating is similar to section steel; and they are reasonable. The numerical simulation shows that the displacement of section steel supporting is smaller than grating supporting. Compared with grating, the displacement on top arch of section steel supporting decreases 16%-18%, the convergence on side wall decrease 23%; the displacement on arch skew decrease 18%. Using twin-side heading method to excavate large-span tunnel in V grade loess tunnel, the surrounding rock has large plastic deformation. Plastic regional development range is very large, and it needs timely supporting. The plastic development scope by grating supporting and section steel supporting is similar.