Dynamic classification of the karst tunnel surrounding rock

The accurate evaluation of karst development situation is hard to given in the investigation and design phases for karst tunnel that cause much difference between the classification results in these phases and those revealed situation during construction,so it's necessary to establish dynamic classification method for karst tunnel during construction.The article got the quantitative assessment method of surrounding rock dynamic classification for karst tunnel through the comprehensive revision of basic quality indicator of rock.And the method is successfully applied to the karst surrounding rock dynamic classification of the Xian Rendong tunnel,which made the surrounding rock classification closed to the actual conditions and ensured the safety and rationality of the construction.