Now in China the tunnels excavated by TBM become deeper and longer than before; and TBM jamming accidents are very common. In order to reduce these accidents

comprehensive evaluation of TBM risk accident induced by tunnel deformation can be carried out in advance. Therefore

the research on comprehensive risk is started. First

the calculated model of comprehensive risk probability is established by probability theory. According to the derived model

the accident probabilities of different consequence ranks can be calculated. Second

the ratio of jamming time and pure penetrating time is used as graded index. The index combined with the data gathered from previous TBM construction is used to divide consequence ranks of construction time delay. Then the comprehensive risk evaluation criterion for deformation is established. Finally

the jamming risk in certain parts of practical project is analyzed by the theory proposed above in two different construction conditions. It is demonstrated from the calculated conclusion that the construction risk is bigger when no measures are taken; however

the risk can be controlled within the acceptable extent when proper measures are taken.