饱和浸水过程矸石胶结充填体强度及损伤特征  

Strength and damage characteristics of cemented gangue backfill during saturated immersion

作　　者：于祥 杨科[1,2,3] 何祥 侯永强[1,3] 文志强 张连富 YU Xiang;YANG Ke;HE Xiang;HOU Yongqiang;WEN Zhiqiang;ZHANG Lianfu(School of Mining Engineering,Anhui University of Science and Technology,Huainan 232001,China;Institute of Energy,Hefei Comprehensive National Science Center,Hefei 230031,China;Joint National-Local Enginering Research Centre for Safe and Precise Coal Mining,Huainan 232001,China)

机构地区：[1]安徽理工大学矿业工程学院,安徽淮南232001 [2]合肥综合性国家科学中心能源研究院(安徽省能源实验室),安徽合肥230031 [3]煤炭安全精准开采国家地方联合工程研究中心,安徽淮南232001

出　　处：《煤田地质与勘探》2025年第2期147-159,共13页Coal Geology & Exploration

基　　金：国家自然科学基金重点项目(52130402);安徽省煤炭安全精准开采工程实验室开放课题基金项目(ESCMMP202402);安徽省关闭/废弃矿井资源开发利用工程研究中心开放基金项目(EUCMR202208);甘肃省青年科技基金项目(24JRRA1012);甘肃省青年博士支持项目(2024QB-103)。

摘　　要：【目的】受充填料浆水、工作面涌水和采空区内积水的影响,矸石胶结充填体的含水率会随浸水时间的增加而发生改变,进而改变了充填体的承载性能。研究矸石胶结充填体在饱和浸水过程的强度特性及损伤破坏特征,对于保持充填体的稳定性和保障煤矿安全至关重要。【方法】通过对饱和浸水过程的矸石胶结充填体开展单轴压缩试验和微观电镜扫描测试,分析充填体强度随浸水时间的变化规律,并基于微元强度统计分布量,建立峰前阶段的分段损伤本构模型,通过微观电镜扫描,揭示饱和浸水过程中矸石胶结充填体强度弱化机制。【结果和结论】结果表明:(1)饱和浸水过程中,胶结充填体单轴压缩下的应力-应变曲线呈现出明显的“四阶段”特征,孔裂隙压密闭合阶段最大应变和应力及峰值应力点应变与浸水时间呈正相关,而峰值应力和弹性模量与浸水时间呈负相关。(2)随着浸水时间的增加,矸石胶结充填体的破坏形态由剪切破坏为主过渡到以张拉-剪切共轭破坏为主,最终转化为以纵向张拉破坏为主,破坏位置主要集中在矸石胶结充填体的中部。(3)建立了考虑孔裂隙压密闭合阶段最大应力和最大应变、弹性模量及峰值应力和峰值应力点应变的分段损伤本构模型,基于试验数据对模型进行了验证,理论模型曲线与试验曲线基本吻合。(4)受水分张力作用、润滑作用及矿物溶解作用的影响,将饱和浸水过程中矸石胶结充填体强度弱化机制分为3个阶段,当充填体达到饱和状态后,其强度持续降低,但是降低速率减小。研究结果可为采空区富水环境下矸石胶结充填开采提供一定的数据支撑。[Objective]Under the influence of backfill slurry,water inrushes in mining face,and water accumulation in goaves,the water content in cemented gangue backfill varies with the immersion time,thus altering the bearing performance of the backfill.Investigating the strength and damage characteristics of cemented gangue backfill during saturated immersion is crucial for maintaining the stability of the backfill and ensuring the safety of coal mines.[Methods]Using uniaxial compression tests and scanning electron microscopy(SEM)of cemented gangue backfill during saturated immersion,this study analyzed the law of changes in the backfill strength under varying immersion times.Based on the statistical distribution of microelement strength,this study established a piecewise damage constitutive model for the ce-mented gangue backfill in the pre-peak stage.Using SEM,this study revealed the mechanism underlying the strength weakening of the cemented gangue backfill during saturated immersion.[Results and Conclusions]The results indicate that during saturated immersion,the cemented gangue backfill under uniaxial compression exhibited significant four-stage stress-strain curves.In the compaction and closure stage of pores and fractures,the maximum strain/stress and the strain at the peak stress point were positively correlated with the immersion time,while the peak stress and modulus of elasticit y were negatively correlated with the immersion time.With an increase in the immersion time,the primary fail-ure morphologies of the cemented gangue backfill transitioned from shear failure to tension-shear conjugate failure,fi-nally shifting to longitudinal tensile failure,with the failures concentrated in the central part of the cemented gangue backfill.This study established a piecewise damage constitutive model for the cemented gangue backfill in the compac-tion and closure stage of pores and fractures that considered the maximum stress and strain,modulus of elasticity,peak stress,and strain at the peak stress point.This model was v

关 键 词：饱和浸水 矸石 胶结充填体 单轴压缩 分段损伤 本构模型 强度弱化机理 

分 类 号：TD353[矿业工程—矿井建设]