喷射混凝土受压损伤本构模型研究

Study of Damage Constitutive Model of Shotcrete under Uniaxial Compression

依据损伤理论和热力学理论,建立喷射混凝土单轴受压损伤本构模型,分别对31个普通混凝土试件、32个喷射混凝土试件的单轴受压试验结果进行统计分析,采用卡方检验方法,确定损伤变量的概型分布函数及相应参数,并分析相同水胶比的普通混凝土与喷射混凝土单轴受压应力应变试验曲线特性,讨论各参数对混凝土峰值应力、峰值应变的影响规律。在传统两参数Weibull分布函数基础上引入损伤阈值这一变量,讨论损伤阈值的取值范围,同时探讨塑性应变对本构模型的影响机制,建立考虑损伤阈值及塑性应变的喷射混凝土单轴受压本构模型。通过与试验及其他本构模型的对比分析,验证所建模型的合理性与适用性。

Based on the damage mechanics and thermo-dynamic theory,the damage constitutive model of shotcrete under uniaxial compression was established.Then,the testing results of uniaxial compression of 31 ordinary concrete specimens and 32 shotcrete specimens were analyzed,while the probability distribution function of the damage variable and the related parameters was determined by chi-square test method.Based on the analysis of the characteristics of stress-strain curves of shotcrete under uniaxial compression and ordinary concrete with the same water-cement ratio,the effects of different parameters on concrete peak stress and peak strain were discussed.With the introduction of damage threshold value based on the traditional two-parameter Weibull random distribution function,the range of damage threshold was discussed.Meanwhile,on the basis of the discussion on the influence of plastic strain on the constitutive model,the damage constitutive model of shotcrete under uniaxial compression considering the effect of damage threshold and plastic strain was proposed.The rationality and applicability of the proposed model were verified by comparison with experiments and other constitutive models.