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为探讨混凝土三轴蠕变特性,采用SAM-2000微机控制电液伺服材料三轴试验机并配备压力自平衡式三轴压力室对混凝土进行了三轴压缩试验和三轴蠕变试验,结果表明:围压的存在可以显著提高混凝土的承载能力,围压越大,混凝土的轴向承载能力越高,蠕变变形量和变形速率越小。假设混凝土破坏为其内部微元破坏累积所致,微元破坏概率与混凝土应变存在一定关系P[ε],且服从Weibull分布,结合三轴压缩试验结果,计算得到了描述混凝土损伤特性的统计损伤变量;基于Burgers流变模型,通过引入损伤变量建立了混凝土三轴蠕变统计损伤模型,利用MATLAB软件进行了模型参数拟合,经对比分析,模型曲线与试验曲线拟合结果较理想,主偏应力越大,拟合结果越精确。此模型可供今后研究参考。
In order to investigate the triaxial creep characteristics of concrete, the triaxial compression test and triaxial creep test of concrete were carried out by using SAM-2000 computer-controlled electro-hydraulic servo triaxial testing machine and self-balancing pressure triaxial compression chamber. : The presence of confining pressure can significantly improve the carrying capacity of concrete. The larger the confining pressure is, the higher the axial bearing capacity of concrete is, and the smaller the creep deformation and deformation rate are. It is assumed that the failure of concrete is due to the accumulation of its internal micro-elements. The probability of micro-elements destruction is related to the concrete strain, P [ε], and follows the Weibull distribution. Combined with the triaxial compression test results, the statistical damage describing the damage characteristics of concrete Based on the Burgers rheological model, a statistical damage model of concrete with triaxial creep was established by introducing damage variables. The parameters of the model were fitted by MATLAB software. After comparison, the fitting results of the model curve and the experimental curve were satisfactory, The greater the stress, the more accurate the fitting result. This model is for future reference.