In underground engineering of city, the constructions of the tunnel will inevitably produce the land subsidence,the building asymmetry decline and other negative influence to the enviroment,this kind of phenomenon is especially outstanding while constructing mutative and large transect multi-tunnel system of urban metro.

In underground engineering of city,the constructions of the tunnel will inevitably produce the land subsidence,the building asymmetry decline and other negative influence to the enviroment,the phenomenon is especially outstanding while constructing mutative and large transect multi-tunnel system of urban metro.

With a growing number of cities of china getting into the construction of the subway, the problems in the construction of the ultra-shallow tunnels increased gradually.

On advance geological forecast of tunnels on karst or varied geological conditions;

Stress on Class tunnel restorations of the first mandibular molar;

The practical method of tunnel entrance landscape design and its design procedure are presented in this paper.

For ensuring the stabilization of slope around tunnel entrance, the tunnel design criterion gives out the definite demands to solpe gradient and excavating high, but these demands are confined only the sort of surrounding rock, can not judge the influence of layer property of surrounding rock and ground water.

Research purposes:The construction of tunnel entrance is the key part of the whole engineering.

By analyzing stress field of cavern tunnel diseases,the causes are studied and five reinforcement and protection grades for cavern tunnel diseases are given according to different defect form,defect behavior and development states,and corresponding examples are given.