Acoustic detection for dam foundation surface excavation influenced by blasting effect of at Dagangshan arch dam

The blasting influence of excavation of Dagangshan arch dam base is detected by using acoustic borehole.First of all,whether the blasting caused the damage of the rock mass of dam base is judged by the attenuation ratio of the wave velocity of rock mass before and after blasting in the course of excavation blasting,so as to reduce the damage of rock mass.Secondly,after the completion of excavation of dam base,the loosing depth of blasting borehole is analyzed through studying onthe characteristic analysis of wave velocity variation of along the boreholes with different depth to provide a reference for further treatment of dam base and consolidation grouting of dam foundation.The results show that the blasting influence of excavation on dam base beis in alongs to the normal range,producing a relative small damage to the rock mass;the blasting can be well controlled in the process of excavation with a small damage of rock mass of dam base.