关键词: 隧道工程, 界限埋深, 浅埋隧道, 变形量, 数值分析

Abstract: Three-dimensional numerical analysis on tunnel excavation was carried out by the finite element software ABAQUS.From the point of view of stress and strain，the definition scope of deep-shallow-buried soil tunnel was studied.The research results show that in the process of tunnel construction，the displacement value of the C point of the vault is the largest，and it has the trend of gradual increase with the increase of the depth of the burial.When the buried depth of the tunnel is increased to a certain critical state，the C point displacement of the vault does not change significantly with the increase of the depth of the burial，but tends to a fixed value.The stress release law of tunnel is the same as its vertical displacement rule.The vertical stress of the C point of the tunnel vault is increased with the increase of the tunnel burial depth，and the change curve of stress also tends to be gentle.The vertical stress of the C point has a good agreement with the calculation value of Terzaghi theory.Based on the above，the critical burial depth value for deep-shallow-buried tunnels was determined by means of theoretical analysis; and the proposed value was further verified by the current specification and Terzaghi theory.

Key words: tunnel engineering, dividing line for deep-shallow-buried tunnels, shallow-buried tunnels, deformation, numerical simulation