岩体冻融疲劳损伤模型与评价指标研究

发布时间：2018-04-03 16:22

本文选题：岩石力学　切入点：冻融循环　出处：《岩石力学与工程学报》2015年06期

【摘要】：岩体冻融损伤模型与评价是研究岩体经历冻胀力萌生、发展与消散反复作用后物理力学性质劣化的主要内容,现有对岩体冻融循环后的损伤评价指标主要有孔隙率、纵波波速、静动弹性模量等物理参数。冻胀力对于岩体可等效为三轴拉伸应力,首先基于三向等效拉应力建立岩体冻融疲劳损伤模型,该冻融损伤演化方程与单轴循环拉应力下的疲劳损伤方程虽然具有同样的形式,但物理意义不同。基于动弹性模量的定义,以孔隙率和纵波波速为参变量推导出了统一的损伤变量表达形式,该损伤变量不仅考虑了双物理参数的影响,还能对不同冻融循环次数下岩石的单轴抗压强度进行较好预测,可作为岩体冻融损伤的评价指标。定义动弹性模量损失40%为岩石冻融破坏临界值,利用该临界值可避免通过试验确定最大冻融循环次数,进而结合统一损伤变量对冻融疲劳损伤演化方程进行求解,最后通过2个实例说明该冻融疲劳损伤模型与评价方法的正确性和实用性。
[Abstract]:The damage model and evaluation of freezing and thawing rock mass is the main content of studying the deterioration of physical and mechanical properties of rock mass after repeated action of frost heave initiation, development and dissipation. The existing damage evaluation indexes of rock mass after freeze-thaw cycle mainly include porosity and longitudinal wave velocity.Static and dynamic elastic modulus and other physical parameters.The frost heave force can be equivalent to triaxial tensile stress for rock mass. Firstly, based on the triaxial equivalent tensile stress, the freeze-thaw fatigue damage model of rock mass is established. The damage evolution equation of freeze-thaw damage is the same as the fatigue damage equation under uniaxial cyclic tensile stress.But the physical meaning is different.Based on the definition of dynamic modulus of elasticity, a unified expression of damage variable is derived by taking porosity and longitudinal wave velocity as parameter variables.The uniaxial compressive strength of rock under different freezing and thawing cycles can also be well predicted and can be used as an evaluation index of rock mass freezing and thawing damage.The 40% loss of dynamic modulus of elasticity is defined as the critical value of freeze-thaw failure of rock. The maximum freezing and thawing cycle times can be avoided by using this critical value, and then the damage evolution equation of freeze-thaw fatigue can be solved with unified damage variable.Finally, two examples are given to illustrate the correctness and practicability of the model and evaluation method.
【作者单位】：中国科学院武汉岩土力学研究所岩土力学与工程国家重点实验室;武汉大学水工岩石力学教育部重点实验室;
【基金】：国家重点基础研究发展计划(973)项目(2014CB046904) 国家自然科学基金重点项目(41130742);国家自然科学基金青年基金项目(41302237)
【分类号】：TU45

【参考文献】