瓦斯爆炸冲击波作用下人工坝体动力响应特征

    Dynamic response characteristics of artificial dam body under gas explosion shock wave

    • 摘要: 为研究瓦斯爆炸冲击波对人工坝体的力学性能的影响,用河沙、碎石、硅酸盐水泥等制作了混凝土试件,进行了动静加载试验,分析了材料在应力作用下的应力−应变关系,阐述了应变率对试件的强度与变形等力学性能的直接影响,并构建了材料的动态本构模型。结果表明:静态压缩试验中,试件的应力−应变曲线分为4个阶段,峰值应力平均值为38.27 MPa,弹性模量为30.4 GPa,泊松比为0.291;霍普金森压杆试验中,当冲击速度为4.8、5.5、7.8 m/s时,试件开始出现“破裂”、“破碎”和“粉碎”状态,试件的应变率和断裂应力成正相关关系,平均应变率在100~250 s−1范围内,试件的峰值应力随平均应变率的增加开始缓慢增加,随后趋于稳定;改进后的ZWT本构方程拟合的曲线拟合度R2达到0.98,充分说明改进后的本构模型对混凝土应力峰值前的动态应力−应变关系有很好的表现力。

       

      Abstract: In order to study the impact of gas explosion shock waves on the mechanical properties of artificial dams, concrete specimens were made using river sand, crushed stones, Portland cement, dynamic and static loading tests were conducted. The stress-strain relationship of the material under stress was analyzed, and the direct impact of strain rate on the mechanical properties such as strength and deformation of the specimens was explained. A dynamic constitutive model of the material was constructed. The results show that in the static compression experiment, the stress-strain curve of the specimen is divided into four stages, with an average peak stress of 38.27 MPa, an elastic modulus of 30.4 GPa, and a Poisson’s ratio of 0.291. In the SHPB test, when the impact velocities are 4.8, 5.5, and 7.8 m/s, the specimens exhibit “fracture”, “fragmentation”, and “crushing” states, respectively. The strain rate of the specimen is positively correlated with the fracture stress, with an average strain rate in the range of 100-250 s−1. The peak stress of the specimen slowly increases and tends to stabilize with the increase of the average strain rate; the curve fitting degree R2 of the improved ZWT constitutive equation is 0.98, which fully shows that the improved constitutive model has a good performance on the dynamic stress-strain relationship before the peak stress of concrete.

       

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