摘要
利用TAW–2000KN压力机、TYJ–500KN压力机和SH–II声发射系统,对粗砂岩和细砂岩进行单轴压缩、巴西劈裂和变角剪切实验,对裂纹扩展过程中的力学特性和声学特征开展研究。实验结果表明:通过统计细砂岩和粗砂岩的单轴抗压、抗拉和抗剪强度可知,岩石抗压和抗拉强度比近似相等,抗剪强度比相差较大。细砂岩和粗砂岩剪切破坏过程声发射特征差异明显,剪应力作用下细砂岩声发射计数曲线变化规律为:(1)–I–(2)–II–(3)(其中"–"表示区间),剪应力作用下粗砂岩声发射计数曲线变化规律为:(1)–I–II–III–(2);声发射能量特点为:细砂岩:呈现弯曲"厂"型,粗砂岩:呈现标准"S"型曲线,且峰前与应力–应变曲线变化规律完全一致。细砂岩和粗砂岩拉伸破坏过程声发射特征差异明显,拉应力作用下细砂岩声发射计数曲线变化规律为:(1)–I–(2)–II–(3)–III,拉应力作用下粗砂岩声发射计数曲线变化规律为:(1)–I–(2)–II–(3)–III;声发射能量特点为,细砂岩:由于局部失稳破坏存在,呈现复杂路径增长,粗砂岩:呈现直线趋势增长。从破坏角度分析,2种岩石区别在于,细砂岩破坏前发生声发射计数和能量的缓慢增长,破坏后出现一定的稳定期。粗砂岩加载前期,高计数信号和低计数信号交替出现,破坏前期和破坏阶段高计数信号和低计数信号混合稀疏出现。细砂岩和粗砂岩单轴压缩过程声发射特征区别较大,声发射计数特点为:细砂岩:(1)–I–(2)–II–(3),粗砂岩:(1)–I–II–(2)–(3);声发射能量特点为:细砂岩:呈现扁平型"S"曲线,粗砂岩:呈现明显"Z"型曲线。利用声发射RA值与平均频率关系能较好反映裂纹类型,拉伸破坏和剪切破坏均符合客观实际。单轴压缩破坏形态给予裂纹类型正反馈,说明应用声发射技术判断裂纹类型有效、可行。
The use of TAW–2000KN press,TYJ–500KN press and SH–II acoustic emission（AE） system,coarse sandstone and fine sandstone under uniaxial compression,Brazil splitting and variable angle shear experiment on crack propagation mechanics characteristics and AE in the process of research. The experiment results show that the tensile strength and shear strength of sandstone and coarse sandstone can be compared with that of the approximate equivalent shear strength ratio and the ratio of shear strength to shear strength is larger than that of the single axial compressive strength. The AE characteristics of the fine sandstone and the coarse sandstone are obviously different. The variation law of AE count curve of fine sandstone under the action of shear stress：（1）–I–（2）–II–（3）（the mark express region by＂-＂）,shear stress gritrock regularity of AE count curve：（1）–I–II–III–（2）. The characteristics of AE energy characteristics are as follows,fine sandstone：present the bending＂厂＂type,coarse sandstone：present the bending＂S＂type. The curves of stress-strain curves are completely consistent. Fine sand and coarse sand rock tensile failure process of AE characteristic differences,The variation law of the AE count curve of fine sandstone under the action of tensile stress：（1）–I–（2）–II–（3）–III,the action of tensile stress gritrock regularity of AE count curve：（1）–I–（2）–II–（3）–III;AE energy features for fine sandstone：local instability damage exists,the complexity of the path curve growth,coarse sandstone：a linear trend growth. From the point of view of failure analysis,the difference between the two types of rock is that the sound emission count and the slow growth of energy before the destruction of fine sandstone,the occurrence of a certain period of stability after the destruction. Coarse sandstone loading period,high count signal and low count signal alternately,failure and failure early stage of high count signal and low count signal mixed sparse. Fine sandstone and coarse sandstone uniaxial compression process of AE characteristics of different AE count features,fine sand：（1）–I–（2）–II–（3）,coarse sand：（1）–I–II–（2）–（3）;AE energy features for fine sandstone：present the bending＂S＂type,coarse sand：present the bending＂Z＂type. The RA value of AE and the average frequency can reflect the type of crack,tensile failure and shear failure are in line with the objective reality. The uniaxial compression damage form given crack types of positive feedback,it is shown the application of AE technology to determine the crack type effective and feasible.
出处
《岩石力学与工程学报》
EI
CAS
CSCD
北大核心
2016年第A02期3458-3472,共15页
Chinese Journal of Rock Mechanics and Engineering
基金
国家自然科学基金资助项目(51574115
51374097
51604100)~~
关键词
岩石力学
拉–压–剪
力学特性
声发射
裂纹类型
rock mechanics
tension-compression-shear
mechanical properties
AE
crack type
