中文摘要：

通过开展不同侧压下的混凝土循环加卸载试验,分析了侧压、应变速率对应力应变全曲线中滞回环面积的影响,提出了一种基于应力应变全曲线的简便滞回环面积统计法,建立了滞回环面积与循环次数之间的关系。结果发现,混凝土单位体积耗散能随着循环次数的增加先增后减,单位体积耗散能最大值与峰值应变有密切联系;在循环加卸载过程中混凝土的单位体积耗散能具有明显的侧压敏感性。利用Weibull统计分布模型对混凝土在循环加卸载过程中单位体积耗散能随循环次数的变化关系进行了拟合分析。计算结果表明：不同侧压下循环加卸载曲线滞回环面积与循环次数服从双参数Weibull模型分布。

英文摘要：

By the cyclic loading and unloading tests on concrete under the conditions of different lateral pressures, making analysis of the enfluences of the lateral pressures and the strain rates on the hysteresis loop area in the stress？strain curve and presenting a simplified statistic method in analyzing the hysteresis loop area based on the stress？strain curves, the relationships between the hysteresis loop area and the cycle number were established in this study. It is found from the analysis results that the dissipation energy of an unit volume of the concrete increases firstly with the increase of the number of cycles and then decreases, and the maximum value of the dissipation energy of an unit volume is closely related with the peak strain. The dissipation energy of an unit volume has an obvious lateral stress sensitivity during the cyclic loading and unloading process. A fitting analysis of the relationships between the dissipation energy and the number of cycles in the process of the cyclic loading and unloading on the concrete specmens was carried out by use of the Weibull statistical model. The calculated results show that the hysteresis loop area and the number of cycles in the cyclic loading and unloading under the different lateral pressures obey the double？parameter Weibull model distribution.