Optimization study on blasting scheme of metro stations subsurface excavating oblique through pile foundations of existing elevated light rail lines

Abstract

Based on the project of digging through the pile foundation of adjacent Qingdao Metro Line 11 at Zhangcun Station of line 4, orthogonal simulation research was carried out, and the influence of different underground running length of adjacent bridge pile was analyzed. Research findings were as follows: (1) The maximum vibration speed generated by the original solution bridge pile is 0.69 cm/s, which is too safe. After the optimization of the scheme, although the maximum vibration velocity generated by the bridge piles is 1.02 cm/s, an increase of 10 m in the blasting section can effectively speed up the construction schedule. (2) Combined with the field monitoring data, it was found that the monitoring data of the optimized scheme was consistent with the simulated data, which verified the accuracy of the simulation, and the new scheme reduced the construction budget by about 15%. (3) The vibration velocity attenuation degree of the rock layer is mainly composed of silty clay > coarse sand > micro weathered granite. (4) Through this optimization simulation, using Ansys/LS-DYNA to modify the K file to apply blasting parameters and initiation points, to obtain an efficient plan and improve the tunnel construction efficiency.