动力损伤后的脆性岩石静力蠕变断裂模型研究  

A STATIC CREEP FRACTURE MODEL AFTER DYNAMIC DAMAGE IN BRITTLE ROCKS

作　　者：李晓照 张骐烁 柴博聪 戚承志 Li Xiaozhao;Zhang Qishuo;Chai Bocong;Qi Chengzhi(School of Civil and Transportation Engineering,Beijing University of Civil Engineering and Architecture,Beijing 100044,China)

机构地区：[1]北京建筑大学土木与交通工程学院,北京100044

出　　处：《力学学报》2023年第4期903-914,共12页Chinese Journal of Theoretical and Applied Mechanics

基　　金：国家自然科学基金(51708016,12172036);北京市教委科研项目(KM202110016014);北京建筑大学金字塔人才培养工程项目(JDYC20200307);北京建筑大学研究生创新项目(PG2022043)资助。

摘　　要：应力波动力扰动下脆性岩石的静力蠕变特性,对深部地下工程围岩变形的评价有重要的实践意义.动力载荷作用导致的局部细观裂纹损伤严重影响脆性岩石蠕变力学行为.基于细观裂纹扩展与应力关系模型、动力扰动损伤演化函数、静动力载荷演化路径函数与黏弹性本构模型,提出一种应力波动力扰动下脆性岩石蠕变断裂特性的宏细观力学模型.其中动力损伤通过控制岩石内部细观裂纹数量变化实现.模型描述了应力波动力扰动下岩石的应变时间演化曲线,解释了岩石动力扰动下蠕变失效特性.研究了不同应力波幅值及周期影响下的脆性岩石应变-时间关系曲线,并通过试验结果验证了模型的合理性.讨论了动力损伤变化形式,突变发生时刻,突变量的大小对岩石蠕变失效特性的影响.分析了应力波幅值、周期对岩石动态动力损伤效应以及蠕变失效特性的影响.主要研究结果:动力损伤的变化值越大,岩石蠕变失效发生时间越短.冲击载荷扰动期间,动力损伤发生的时刻及增加的形式,对动力扰动后的岩石应变及蠕变破坏时间影响很小.动力损伤变化量随应力波幅值增加、周期减小而加速增大.应力波幅值越大、周期越小,岩石发生蠕变失效时间越短.The static creep characteristics of brittle rock under dynamic stress wave disturbance are of great practical significance to the evaluation of surrounding rock deformation in deep underground engineering.The localized damage of microcracks under dynamic loads can seriously affect the creep mechanical behavior of brittle rocks.Based on the relationship model between microcrack growth and stress,dynamic damage evolution function,dynamic-static load path function and viscoelastic constitutive model,a micro-macro mechanical model considering the creep fracture characteristics of brittle rock under the dynamic disturbance of stress wave is proposed.The dynamic damage is realized by controlling the initial microcrack number.This model describes the strain curve with time under stress wave disturbance,and then explains the creep failure characteristics of rock under stress wave loading.The strain-time relation curves of brittle rock under the influence of different stress wave amplitudes and periods are studied,and the rationality of the model is verified by the test results.The influence of the change form,the time of a sudden change and the magnitude of a sudden change for the dynamic damage on the creep failure characteristics of rock are discussed.The effects of the amplitude and period of stress wave on dynamic damage effect and creep failure characteristics of rock are analyzed.The main results:the larger the change value of dynamic damage,the shorter the creep failure time.The happened time and the increasing form of dynamic damage during impact loading damage have little effect on the strain and creep failure time of the rock after dynamic disturbance.The dynamic damage experiences an accelerated increase with the increment of stress wave amplitude and the decrement of the stress wave period.The larger the stress wave amplitude,the smaller the period,and the shorter the creep failure time of the rock.

关 键 词：脆性岩石 宏细观力学关系 静力断裂 动力损伤 应力波特征 

分 类 号：TU452[建筑科学—岩土工程]