Abstract: According to the sketch and the actual geological conditions in excavation,room-to-tail transfer engineering geology,geological conditions in excavation,the main engineering geological problems and the tailwater room spray crown profile of cracks introduced factors from the construction,geological factors,stress factors,temperature,relaxation cycle factors,spray protect joints,Shouli Bu equal factors were analyzed and investigated,that the crown parallel to the axial opening cracks in the structure factor,the major stress factors,blasting disturbance and support not due in time for the incentives.Surrounding rock mass destruction and for the stress-control damage-control block combination.