高温损伤后岩石动态损伤本构模型

为了研究高温损伤后岩石动态本构模型,通过组合建模的方法,引入裂隙体,并与损伤体串联,经理论推导,最终建立了高温后岩石全过程动态本构模型。随后开展了25~600 ℃温度处理后的花岗岩动力冲击试验。研究结果表明:随着温度升高,花岗岩动态峰值应力减小,弹性模量则先增大后减小;核磁共振测试结果能够定量描述高温引起岩石内部孔隙以及孔径分布,T2谱面积随温度升高呈现指数增长规律;试验结果验证了高温损伤后岩石动态损伤本构模型的适应性,理论计算结果与试验数据相关性达0.98以上;裂隙体参数a和b控制了应力应变曲线压密段的曲线形状,且曲线对参数a更为敏感。

A Novel Dynamic Constitutive Model after Temperature Damage for Rock

To study the dynamic constitutive model of rock in consideration of high-temperature damage,a novel modeling method is proposed.This model contains a fractured body and a damaged body connected in series with each other.Dynamic compression tests on granite were carried out with Split-Hopkinson pressure bar under temperature of 25-600 ℃.Results demonstrate that the dynamic peak stress of granite decreases with the climbing of temperature,while the elastic modulus firstly increases and then decreases.The pore characteristics of rock induced by high temperature can be reflected quantitatively by nuclear magnetic resonance test,and the T2 spectrum area displays an exponential growth with the rising of temperature.The adaptability of the proposed model is verified by the dynamic compression tests,and the correlation between theoretical and experimental data is over 0.98.The shape of compaction stage of stress-strain curve is controlled by parameters a and b of fracture body,of which parameter a has a larger influence.