The paper studies the effects of different microstructures on the hydrogen resistance properties. Four kinds of microstructures were obtained by using four kinds of heat treatment processes for 45 steel materials. The mechanical properties of different microstructure materials were obtained by Vickers hardness test and internal residual stress test. The relationships between hardness and depth of four kinds of microstructures were obtained by stratified microhardness test. Static hydrogen resistance property of different microstructures was obtained by using the stripping method. Results show that the H2S corrosion layer of different microstructures is basically the same, and the depth and hardness distribution of the hydrogen embrittlement layer are quite different. More pearlite, lead to the weakness of hydrogen resistance property; quenched and tempered sorbite after the hydrogen corrosion is better than ferrite + pearlite structure, martensite has a good resistance to hydrogen permeability. Finally, the relationships between microhardness and depth of the hydrogen embrittlement layer with different microstructures were fitted.

GAP model will be modified and programmed by FISH language, which can be used in FLAC2D programs. The modified GAP model is used to study the variation of surface settlement shape with depth, the variation of the maximum settlement value with depth, and the variation of settlement gradient with depth. The results show that: the settlement shape is narrow and deep with the conditions of shallow buried depth of tunnel; on the contrary, the settlement shape is wide and shallow; When the tunnel depth is less than the critical value, the tunnel depth and the maximum surface settlement is approximately linear; when the tunnel depth is greater than the critical value, the curve of maximum surface settlement value with depth becomes flat and with the increase of the tunnel, the surface settlement gradient gradually decreases and eventually tends to zero. It is more reasonable to assess the influence of tunnel excavation near adjacent buildings, using the maximum surface settlement and the settlement gradient as a control standard.