摘要
To investigate the effects of water and cyclic loading on dolomite’s mechanical properties during deep mining,mechanical experiments on non-pressure water absorption and cyclic loading were conducted.The findings reveal that the elastic modulus and Poisson ratio of dolomite fluctuate with increasing water content.The mass of water absorption is positively correlated with time and the water absorption stage can be divided into three stages:accelerated,decelerated,and stabilized stages.During this process,the number of pores in dolomite increases,while the pore diameter initially decreases and then fluctuates.Microscopic analysis shows that the proportion of mesopores first increases and then decreases,while micropores exhibit the opposite trend,and the proportion of macropores fluctuates around 0%.A model diagram of structural evolution during water absorption has been developed.Additionally,the softening process of dolomite’s water absorption strength is categorized into three stages:a relatively stable stage,an accelerated softening stage dominated by mesopore water absorption,and a decelerated softening stage characterized by micropore water absorption.A uniaxial damage constitutive model for dolomite under water influence was established based on the Weibull distribution and Mohr-Coulomb strength criterion,and experimental validation indicates its strong applicability.
为探究深部开采过程中水和循环载荷对白云岩力学性能的影响,通过无压吸水和循环加卸载力学实验,分析了含水饱和度对白云岩力学特性的影响,得到了吸水过程中孔隙结构随时间变化的规律。结果表明:白云岩的弹性模量和泊松比随着含水饱和度的增加呈波动变化趋势。吸水质量与时间呈正相关关系,吸水阶段可分为加速吸水、减速吸水和稳定吸水阶段。吸水过程中白云岩孔隙数量不断增加,孔径先减小,后续波动变化。微观分析表明,在吸水过程中孔隙的中孔比例先增大后减小,微孔比例先减小后增大,大孔比例在0%附近波动,并建立了吸水过程中不同尺度的结构演化模型图。白云岩吸水强度软化过程可分为3个阶段,前期为相对稳定阶段和加速软化阶段,主要发生中孔吸水,后期进入减速软化阶段,发生微孔吸水。同时,基于Weibull分布和Mohr-Coulomb强度准则,建立了水作用下的白云岩单轴损伤本构模型,并结合实验数据进行了验证,结果显示所建立的本构模型适用性较好。
基金
Project(IMRI23005)supported by Ordos Science and Technology Bureau,China
Projects(52174096,52304110)supported by the National Natural Science Foundation of China。
作者简介
Corresponding author:SHI Fu-kun,PhD,E-mail:shifukun2020@163.com,ORCID:https://orcid.org/0009-0004-9959-0561。
