The Study About Tunnel Smooth Blasting Of The Quaternary Basalt In Changbai Mountain

Changbai Mountain area will become important tunnel construction site alongwith the development of Changbai Mountain scenic area for “World Natural Heritage”and the improvement of national highway network planning. Changbai mountain areais the largest distribution area of the Quaternary basalt, there are some characteristicin the basalt area, such as in short form, multistage eruption, prominent of volcaniceruptive rhythm, development of primary columnar. Based on this background, thisarticle is in detail and depth study about the tunnel smooth bleating in ChangbaiMountain quaternary basalt.Combination with the location of Changbai Mountain area and the formation ofthe volcano eruption sequence in the new generation eight volcano activity, there aredetail and depth study in distribution range, mineral composition and structure,physical and mechanical parameters, the special structure of rock mass and theengineering geological properties of basalt. The study about columnar section is fromformation conditions, the classification of columnar section and the structure ofcolumnar section.Simulate the smooth blasting influence of the included angle between jointfissure and hole connection by Ansys. When the included angle is between70°and90°, the influence of joint fissure is very little. When the included angle is less than70°, there will be alternate serrated between super and owes digs. Conduct theoreticalanalysis by theory of blasting.Based on the influence of joint fissure to smooth blasting, study the influence ofcolumnar joint to smooth blasting by the theory of blasting, wave theory and thetheory of fracture mechanics. According to the type and the exposed location ofcolumnar joint, study the smooth blasting influence of columnar joint and how toadjust the blasting parameters.(1) When the columnar joint is minimum, very small and small, there will besawtooth between super and owes digs. Encryption blast hole of the intersection position of columnar joints and hole connection.(2) When the columnar joint is on the top of the tunnel, we conduct blasting design inaccordance with the conventional design method.(3) When the columnar joints are in the bottom of the tunnel, we should reduce “E”and “W”(4) When there are a plurality of columnar sections between the holes, there will besawtooth between super and owes digs in the intersection position of columnarjoints and hole connection, there will be super digs in columnar joints. We shouldreduce “E” and “W” and use interval charge.When there are columnar joints, blasting parameter adjustment conducts fromreducing “E” and “W”, but there are some influence of hole depth, decouplecoefficient and charge density coefficient. Put forward a new method of calculatinghole distance, but the applicability of the new method need inspection of a lot ofengineerings. When the columnar joints are medium, large, very large and theextremely,“W” is equal to the width of the columnar joints. In other cases, we cancalculate “W” according to “E” and “m”.