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.