白垩系冻结砂岩动态统计损伤本构关系研究  

Study on dynamic statistical damage constitutive relation of cretaceous frozen sandstone

作　　者：秦越 王磊[1] 苏宏明 陈世官 QIN Yue;WANG Lei;SU Hong-ming;CHEN Shi-guan(School of Architecture and Civil Engineering,Xi'an University of Science and Technology,Xi'an 710054,China)

机构地区：[1]西安科技大学建筑与土木工程学院,西安710054

出　　处：《工程爆破》2021年第3期42-50,共9页Engineering Blasting

基　　金：国家自然科学基金资助项目(41702339,51404193)。

摘　　要：为了研究饱和冻结砂岩的本构关系,依托白垩系地层煤矿立井建设中冻结凿井工程,开展室内SHPB冲击试验获取冻结砂岩在不同应变率下的动态应力应变曲线,在分析岩石动力学特性的基础上,建立了基于Weibull统计分布、Drucker-Prager破坏准则及等效应变原理的砂岩强度型动态统计损伤本构关系。结果表明:冻结砂岩动态应力应变曲线分为线弹性、弹塑性及塑形软化3个阶段,动态抗压强度与峰值应变的应变率ε强化效应显著;随ε的升高,岩石用于内部微缺陷衍生和扩展的能量逐渐变大,参与破坏过程的裂隙增多,宏观上表现出比能量吸收值(SEA)的应变率相关性明显;统计本构关系中,表征岩石初始微缺陷的损伤系数δ能够反映饱和冻结砂岩受冲击时的弹塑性特征,经拟合确定最佳初始损伤系数δ=0.95;理论模型曲线与试验曲线吻合良好,模型能较好地反映冲击载荷下岩石线弹性和弹塑性阶段的强度分布。In order to study the constitutive relationship of the saturated frozen sandstone,the indoor SHPB impact test was carried out to obtain the dynamic stress-strain curves of frozen sandstone under different strain rates based on the Frozen Shaft Sinking Engineering in the construction of coal mine shaft in the Cretaceous strata.Based on the analysis of rock dynamic characteristics,the strength type dynamic statistical damage constitutive relation of sandstone is established based on the Weibull statistical distribution,the Drucker Prager failure criterion and the equivalent strain principle.The results show that the dynamic stress-strain curve of frozen sandstone can be divided into 3 stages:the linear elastic stage,the elastic-plastic stage and the plastic softening stage.The strain rate strengthening effect of dynamic compressive strength and peak strain is significant.With the increase of strain rate,the energy used for the derivation and expansion of internal micro defects gradually increases,and the number of cracks involved in the failure process increases.The strain rate dependence of specific energy absorption(SEA)is obvious.In the statistical constitutive relation,the damage coefficient of rock initial micro defects can reflect the elastic-plastic characteristics of the saturated frozen sandstone under impact,and the bestδdetermined by fitting isδ=0.95.The results show that the curves of the theoretical model are in good agreement with the experimental curves,and the model can well reflect the strength distribution of rock in linear elastic and elastic-plastic stages under impact load.

关 键 词：岩石力学 霍普金森压杆 白垩系冻结砂岩 微元强度 动态本构关系 

分 类 号：TD235[矿业工程—矿井建设] TD31