Abstract

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.

摘要

深部地下洞室爆破开挖对围岩的破坏作用是不可避免的。为准确分析高地应力条件下爆炸载荷对围岩的破坏程度，基于动态有限元数值模拟软件，提出了一种改进的岩体破坏本构模型，以及岩体劣化的连续变化过程。研究了爆破动力扰动下的质量材料参数和损伤阈值。基于溪洛渡水电站地下厂房爆破开挖振动监测数据，对比了几种不同本构模型的现场实测数据和数值模拟结果，分析了不同本构模型和爆炸载荷对本隧道及相邻隧道围岩振动传播衰减规律的影响。结果表明，改进后的损伤本构模型计算结果更接近现场实测值。相同装药量下，围岩破坏深度主要受弹筒直径的影响，孔距的变化只会影响围岩的破坏范围。