Blasting Construction Damage To New Concrete Lining Structure Analysis

In the past few years, with the rapid development of the national economy, there are more and more underground engineering being constructed, such as the railway and road tunnel, the hydroelectric project, the municipal project, military and defense project and so on. During the construction of underground engineering, the influences of blasting load on the concrete structure have always been concerned by scientists and engineers. Those researches centered on the explosion seismic effect caused by the excavating blast and the criterions of safety vibration velocity for different concrete structures. According to the concrete damage theory, the influence of air shock wave caused by the underground excavating blast on fresh shotcrete lining structure have been analyzed by finite element simulation technique in this paper. The results of analysis show the maximum damage degree of shotcrete lining structure quantitatively. The author also analyzes the piling damage of the lining structure under repetitious blasting wave load, made a comparison between the damage influences of lining from the shotcrete layer thickness, drifting footage and time of working circulation, amount of dynamite and some other factors as well, summarize the regulation of the damage development in lining structure. A commendation of maximum permissible damage degree of concrete lining structure has been presented. Based on the limited damage degree, the safety amounts of dynamite under different excavating condition are given in conclusion. Those are very important references in underground excavating blast and initial shotcrete lining design.Furthermore, the method to analyze the damage of lining structure by current finite element software ANSYS is also valuable to other concrete structure and components.