承压饱和破碎岩石颗粒破碎及渗透率演化特征研究  

Particle crushing and permeability evolution of saturated broken rock under compaction

作　　者：郁邦永[1] 潘书才[1] 魏建军[1] 岳翎 郭静那 YU Bangyong;PAN Shucai;WEI Jianjun;YUE Ling;GUO Jingna(Institute of Construction Engineering Technology,Changzhou Vocational Institute of Engineering,Changzhou,Jiangsu 213164,China;State Key Laboratory for Geomechanics&Deep Underground Engineering,China University of Mining&Technology.Xuzhou,Jiangsu 221116,China)

机构地区：[1]常州工程职业技术学院建筑工程学院,江苏常州213164 [2]中国矿业大学深部岩土力学与地下工程国家重点实验室,江苏徐州221116

出　　处：《采矿与安全工程学报》2020年第3期632-638,共7页Journal of Mining & Safety Engineering

基　　金：常州市科技项目(CJ20190020);江苏省高等学校自然科学研究项目(18KJB440002);江苏省住建系统科技项目(2017ZD169,2018ZD199);江苏省青蓝工程项目

摘　　要：为探求破碎岩体颗粒破碎及渗透率演化规律,对饱和破碎岩石进行侧向受限下的压缩和渗透试验,利用显微CT观察试样内部的孔隙结构形态,引入相对破碎率定量研究岩石颗粒的破碎规律,并分析其与孔隙度和渗透率之间的关系。试验结果表明,颗粒破碎在压实过程中普遍存在并持续改变试样的粒度分布,在轴向应力达到2 MPa时,细小颗粒(0~2.5 mm)大量出现,占最终增加量的44.6%,同时大颗粒(12~15 mm)明显减少,占最终减小量的45.1%;而应力升至12 MPa后,小颗粒(0~2.5 mm和2.5~5 mm)小幅变化,其余各粒径区间内岩石颗粒的质量变化微弱。相对破碎率和渗透率的变化范围分别为0~0.3693和3.48×10-14~67.16×10-14m2,且两者的变化过程均可分为2个阶段,即当轴向应力小于4 MPa时,相对破碎率快速增大,占总增幅的65.6%~74.1%,渗透率快速减小,占总降幅的84.4%~91.1%;而当轴向应力大于4 MPa时,相对破碎率缓慢增大并趋于稳定,渗透率缓慢减小并趋于稳定。渗透率与相对破碎率之间关系可用二次多项式函数拟合,相对破碎率可作为评估渗透率的有效参量。初始粒径配比对渗透率有明显影响,在相同轴向应力下,Talbot指数越大,渗透率越小;而初始粒径配比对相对破碎率几乎无影响。In order to study particle crushing and permeability evolution of saturated broken rock,lateral confined compression tests and seepage tests for saturated crushed rock have been conducted.Micro-CT system has been used to observe the microstructure of the samples and relative breakage has been introduced to quantitatively study the destructive rules of particle crushing,and then the influence of relative breakage on porosity and permeability has been analyzed.The experimental results have indicated that during compaction,particle crushing is pervasive and continuously changes the particle size distribution o f the samples.When the axial stress reaches 2 MPa,small particles(0-2.5 mm)appear in large numbers by 44.6%of total increase;meanwhile,the mass o f large particles(12-15 mm)decreases significantly by 45.1%o f the total decrease.However,after the axial stress exceeds 12 MPa,the mass o f small particles(0-2.5 mm and 2.5-5 mm)changes slightly,and the mass o f rock particles in other sizes changes weakly.The variation ranges o f relative breakage and permeability are 0-0.3693 and 3.48x 10'14-67.16x 10"14 m'respectively,and the change process o f both can be divided into two stages.When the axial stress is less than 4 MPa,the relative breakage increases rapidly by 65.6%-74.1%o f the total increase,and the permeability decreases rapidly by 84.4%-91.1%o f the total decrease.When the axial stress is greater than 4 MPa,the relative breakage increases slowly and tends to be stable,while the permeability decreases slowly and tends to be stable.The relationship between permeability and relative breakage can be fitted by a quadratic polynomial function,which means that the relative breakage can be used as an effective parameter to evaluate the permeability of saturated crushed rock.The initial gradation has a significant impact on the permeability.Under the same axial stress,the larger Talbot exponent corresponds to a smaller permeability,while the initial gradation has little effect on the relative breakage.

关 键 词：饱和破碎岩石 粒度分布 相对破碎率 渗透率 初始粒径配比 

分 类 号：TD315[矿业工程—矿井建设]