With increased urban highway tunnel construction in P.R. China

there are more shallow cover tunnels passing under buildings.Finding a means to appraise buildings' degree of damage is one of the most important preconditions so that tunnels can safely pass under buildings.First

the instance of damage should be confirmed according to the buildings' actual settlement.Then

referring to the buildings damage evaluation criteria

the buildings' control damage rank and critical distortion value can be determined.The permissible distortion value can be drawn from the difference of buildings' critical distortion value and distortion value corresponding to its damage ranking.Finally

a three-stage appraisement is carried out to assess the degree of buildings' damage induced by tunnel construction.If every stage's calculated result of this appraisement exceeds buildings' permissible distortion value

the buildings should be reinforced to assure that the tunnels could pass through safely.At the same time

the calculation method has important reference value for the similar projects.