Application of the technique of pentagon hollow cutting-in in tunneling;

In this paper the construction plan of mid depth parallel cut blast is introduced, meanwhile some important technical questions are pointed out.

Combining the specific engineering practice,this paper discussed the theoretic and practical bases of reasonable lying of the cuttings hole toward characteristics of the big cross-section sap tunneling demolition,and calculated the reference quantity of explosive in single hole under condition of the mild-rigidity rocks.

By using the LS-DYNA 3D nonlinear dynamic finite element software,the elasticity calculation model was established to analyze the generation and transmission of stress under explosive charge in 4 typical cutting patterns,those used in shaft excavation by one-step blasting were optimized and compared by numerical simulation to select the optimizing cutting patterns.

In this paper, the author combined the experience of tunnelling construction bystraight-in hole cutting blasting within 30 years in the country with the theory and practice in the blasting wor of Sweden, U.

The movement law of the smashed rock mass in the cut blasting was studied using two phase flow method drawn on the experience of industry.

Physical models of fragment discharge process are established and the fragment discharge law is discussed by the rational simplification of parallel-cut blasting process in this paper.