Numerical analysis on rock blasting damage in Xiluodu underground powerhouse using an improved constitutive model

Damage effect on surrounding rock is unavoidable during blasting excavation of deep underground caverns. In order to accurately analyse the damage degree of surrounding rock caused by explosive load under high ground stress conditions, an improved damage constitutive model of rock mass is proposed based on dynamic finite element numerical simulation software, and the continuous change processes of the deterioration of rock mass material parameters and damage threshold under blasting dynamic disturbance are studied. Based on the monitoring data of blasting excavation vibration of underground powerhouse in Xiluodu Hydropower Station, the field measured data and numerical simulation results of several different constitutive models are compared, and the effects of different constitutive models and explosive loads on vibration propagation attenuation law of surrounding rock of this tunnel and adjacent tunnel are analysed. The results show that the calculated results of the improved damage constitutive model are closer to the field measured values. The damage depth of surrounding rock is mainly affected by the diameter of cartridge under the same charge quantity, and the change of the hole spacing will only affect the damage range of surrounding rock.