Vibration load in foundation excavation blasting process is easy to affect the retaining pile structure.Pre-set damping holes close to the surrounding pile structure is an important control measure.In order to evaluate the vibration damping effect of the retaining pile structure under the action of blasting damping holes,the vibration velocity of the top part of the retaining pile structure was obtained by on-site vibration monitoring analysis based on the Wuhan Metro Line 7 Julong Avenue Station pit blasting project.LS-DYNA software was used to establish the numerical calculation model of foundation pit blasting.On the basis of verifying the reliability of the calculation model and parameters by combining the field monitoring data,the calculation scheme of the combination of vibration damping hole parameters was designed by using the control variable method,and the influence law of each parameter on the vibration damping effect was calculated and analyzed.The safety criterion for the stability of the retaining pile structure was proposed.The dynamic response characteristics of the retaining pile structure was analyzed in the optimal damping hole damping scheme,and its on-site engineering application inspection was realized.The optimal damping hole damping scheme for the retaining pile structure was proposed,the dynamic response characteristics of the retaining pile structure under its action were analyzed,and its field engineering application test was realized.The results show that the vibration damping effect of vibration damping hole is related to the hole diameter,hole depth,hole spacing and number of rows of vibration damping hole,among which the hole depth,hole spacing and number of rows of vibration damping hole have greater effects on the vibration damping effect,while the vibration damping hole diameter has a smaller effect on the vibration damping effect.The safety criterion for blasting vibration velocity of the retaining pile structure is 26.10 cm/s.A double-row plum-shaped damping hole with a hole diameter of 100 mm,a spacing of 0.2 m and a hole depth of 0.7 m is used as the optimized design scheme.In this scheme,the maximum vibration velocity of the retaining pile is 25.57 cm/s,which is less than the safety criterion of blasting vibration velocity.
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