地震作用下岩石材料的动态特性及本构关系研究

As an important infrastructure for national strategy and lifeline engineering, once the underground engineering is in the complex seismic geological environment and it have significant seismic safety problems, and dynamic properties and constitutive model for rock of underground engineering under seismic load is urgent research topic. Taking Xianglushan tunnel of the water diversion project in central Yunnan as an engineering background, and based on the results related to rock dynamics, the project takes the form of seismic load as the entry point. Dynamic loading test of rock under medium and low strain rates, and low cycle constant and variable amplitude cyclic loading test of different loading frequencies are done. The further study for dynamic mechanical characteristics and coupling effect between rate effect and damage effect of rock under seismic load are made. Based on these, the adaptability formula for kinetic parameters of the rock related to strain rates and the damage factor evaluation model and the comprehensive characterization of both are built. Then, according to the subloading surface theory, the dynamic constitutive model for the rock is established which can reflect the strain rate effect, hysteresis characteristic and cumulative deformation and damage effect under seismic load by take the comprehensive characterization as an internal variable. Finally, on this basis, the realization of the dynamic constitutive model for the expansion of different types of rocks is done based on previous achievements. The results can effectively promote the development of dynamic constitutive model of rock material and its application in rock underground engineering and provide technical support for the evaluating and forecasting of the rock stability in underground engineering.

岩石地下工程作为国家战略和生命线工程的重要基础设施，一旦面临复杂地震地质环境，其地震安全问题突出，地震作用下岩石材料的动态特性及本构关系研究是亟待突破的理论与技术难题。本项目以滇中引水工程香炉山隧洞为依托工程，以岩石动力学相关成果为基础，以地震作用荷载形式为切入点，开展岩石的中低应变率动态加载试验、相同和不同加载频率低周变幅循环荷载试验，深入研究地震作用下岩石的动态力学特性及率效应与损伤效应的耦合作用，建立动力学参数率相关适应性公式、损伤演化因子评价模型和两者耦合的综合表征量；基于次加载面理论，以综合表征量为内变量，建立综合反映地震作用下岩石率效应、滞回圈与累积变形、损伤效应等特征的动态本构模型；以前人成果为基础，实现该动态本构模型对不同类型岩石的扩展应用，从而有效推动岩石材料动态本构模型的发展以及在岩石地下工程中的应用，为地震作用下岩石地下工程的稳定性评价与预测提供技术支持。

地震作用下岩石材料的动态特性及本构关系研究是面临复杂地震地质环境岩石地下工程亟待突破的理论与技术难题。本项目以滇中引水工程香炉山隧洞为依托工程，开展了岩石的中低应变率动态加载试验、不同加载频率低周变幅循环荷载试验，基于统计分析，确定了适用于不同岩石材料的强度和模量在中低应变率下的统一动态增强因子模型；基于CWFS模型，提出了能反映循环荷载下岩石粘聚力和内摩擦角等强度参数损伤演化的一种修正CWFS模型；分析和明确了岩石材料率效应和损伤效应的相互关系，基于修正CWFS模型和中低应变率下的统一动态增强因子模型，构建了描述岩石强度和模量等动力学参数与应变率和损伤因子共同关系的表达式；基于次加载面理论，结合描述岩石动力学参数与应变率和损伤因子共同关系的表达式，建立了能有效反映岩石在地震作用下所表现出的率效应、滞回圈与累积变形以及损伤效应等动态力学特性的动态本构模型；通过数值实验，揭示了真三轴不同加载频率循环荷载下岩石的动态力学性质，实现了岩石动态本构模型的扩展应用，从而有效推动岩石材料动态本构模型的发展以及在岩石地下工程中的应用，为地震作用下岩石地下工程的稳定性评价与预测提供了技术支持。