摘要
岩石含水饱和度与水分分布影响劈裂面粗糙度,进而决定断裂面渗流性能和摩擦作用,对分析巷道围岩稳定性和水压致裂增透效果至关重要。通过对不同饱和度(0,25%,50%,75%和100%)砂岩进行核磁共振分析和巴西劈裂试验,并对岩样劈裂面进行三维形貌扫描,研究饱和度对砂岩劈裂特征的影响。研究结果表明:(1)岩样从干燥到饱和,抗拉强度从3.05 MPa降至0.98 MPa,符合指数函数特征。岩样的硬度从干燥到饱和下降56.6%,高饱和度砂岩塑性增强。(2)劈裂面分形维数随饱和度增加呈对数型增大。裂隙面粗糙度系数(JRC)随饱和度增高,均值从5.598增至13.306,且非饱和状态JRC表现出明显的离散性。(3)利用统计学原理量化不同饱和度砂岩劈裂面,发现粗糙度高度、坡度均值和标准差均随饱和度升高增大,坡向则由干燥的均匀分布逐渐趋于集中在270°。饱和程度加大,垂直裂隙增多,劈裂面更加粗糙。(4)核磁共振分析结果表明,随着吸水饱和度的增加,水由岩样周边向内部运移,岩样内部孔隙润湿量逐渐增加。随着饱和度从25%升高至100%,岩样内部大中孔和微裂隙润湿比例由3%升高至17%,促使岩样生成软弱结构,破坏时由穿晶裂隙逐渐演化为晶间裂隙,导致宏观表现为劈裂面更加粗糙。
The water saturation and distribution of rocks affect the roughness of the fracture surface,which in turn determines the seepage performance and friction effect of the fracture surface.It is crucial for analyzing the stability of the surrounding rock of the roadway and the effect of hydraulic fracturing induced permeability enhancement.In this paper,nuclear magnetic resonance analysis and Brazilian splitting experiments are performed on sandstones with different saturations(0,25%,50%,75%and 100%).Three-dimensional morphology scanning of the rock sample splitting surface are also conducted.The effect of saturation on the splitting characteristics of sandstones was studied.The results show that:(1)From dry to saturated,the tensile strength of rock sample decreased from 3.05 MPa to 0.98 MPa,which conforms to the characteristics of Exponential function.Rock hardness decreased by 56.6%from dry to saturated.Plasticity enhances in highly saturated sandstone.(2)Splitting surface fractal dimension increases logarithmically with saturation.With saturation increasing,the mean value of joint roughness coefficient(JRC)increases from 5.598 to 13.306.The unsaturated JRC exhibits significant discrete.(3)The splitting surface of sandstone with different saturations was quantified using statistical principles.It is found that the roughness height,slope mean and standard deviation increase with saturation,while the slope direction gradually tends to be concentrated at 270°from a uniform distribution in drying.The increase in saturation promotes an increase in vertical fractures,ultimately leading to a rougher splitting surface.(4)NMR analysis shows that with water saturation increasing,water is transported from the periphery to the interior of the rock sample,and the pore wetting within the rock samples gradually increases.As the saturation increases from 25%to 100%,the wetting ratio of large and medium pores and microcracks inside the rock sample increases from 3%to 17%,which promotes the formation of weak structures in rock samples.It causes the transgranular cracks gradually evolve into intergranular cracks in splitting test,resulting in a coarser macroscopic appearance of the splitting surface.
作者
张村
王潇杰
师旭涛
赵毅鑫
韩鹏华
张通
ZHANG Cun;WANG Xiaojie;SHI Xutao;ZHAO Yixin;HAN Penghua;ZHANG Tong(Beijing Key Laboratory for Precise Mining of Intergrown Energy and Resources,China University of Mining and Technology(Beijing),Beijing 100083,China;Joint National-Local Engineering Research Centre for Safe and Precise Coal Mining,Anhui University of Science and Technology,Huainan,Anhui 232001,China;Engineering Research Center of Green and Intelligent Mining for Thick Coal Seam,Ministry of Education,China University of Mining and Technology(Beijing),Beijing 100083,China)
出处
《岩石力学与工程学报》
EI
CAS
CSCD
北大核心
2024年第S02期3722-3737,共16页
Chinese Journal of Rock Mechanics and Engineering
基金
国家自然科学基金资助项目(52474161)
安徽理工大学煤炭安全精准开采国家地方联合工程研究中心开放基金资助项目(EC2022012)
中央高校基本科研业务费专项资金资助(2024ZKPYNY01)
关键词
岩石力学
巴西劈裂
3D形貌扫描
饱和度
劈裂面
粗糙度
rock mechanics
Brazilian splitting tests
3D morphology scanning
saturation
splitting surfaces
roughness
作者简介
张村(1990-),男,2017年于中国矿业大学采矿工程专业获博士学位,现任副教授、博士生导师,主要从事矿井水防治与利用等方面的研究工作。E-mail:cumt-zc@cumtb.edu.cn;通讯作者:张通(1990-),男,现为副教授、博士生导师。E-mail:1099731996@qq.com
