摘要
采用自制的压–拉转换装置,配合RMT 150C岩石力学试验系统及数字散斑相关方法,对双边非对称裂纹类岩石平板试样进行直接拉伸试验,得到类岩石试样的拉应力–应变曲线、试样表面应变场演化过程和裂纹扩展模式。研究发现,类岩石试样直接拉伸的拉应力–应变曲线大致可以分为4个阶段:(1)近似线性阶段,预制裂纹基本不起作用,应力随应变增加较快,试样表面应变场的分布主要受试样内部的孔隙及颗粒的影响;(2)整体缓慢增加阶段,两预制裂纹和试样内部的孔隙及颗粒共同影响试样表面应变场的分布,整体上应力随应变呈增加趋势;(3)短暂峰值过渡阶段,试样中某个预制裂纹对试样表面应变场的分布起决定性作用;(4)破坏阶段,裂纹起裂位置在应变场相对集中区域,并扩展导致试样破坏。对于直接拉伸条件下的双边非对称裂纹平板试样,其中某条预制裂纹会率先扩展,先向远离前方裂纹的方向扩展,再向靠近前方裂纹的方向扩展,对采用数值模拟方法研究张拉应力状态下裂纹相互作用扩展规律具有重要意义。
Based on self-designed pressure-tension conversion device and the RMT150 C rock mechanics test system, the direct tension tests of the bilateral asymmetric cracked rock-like plate specimen have been carried out with the digital speckle correlation method(DSCM); and then the tensile stress-strain curves, the evolution of the surface strain fields and the crack propagation modes are obtained correspondingly. The results show that the tensile stress-strain curve of rock-like specimen can be roughly divided into four stages:(1) The approximate linear stage, the prefabricated crack basically do not work, the stress increases rapidly with strain, and the specimen surface strain field distribution is mainly affected by the internal pores and particles.(2) The whole slowly increasing stage, the two prefabricated cracks and the pores and particles in the specimen affect the distribution of the surface strain field; and the stress increases with strain on the whole.(3) The short peak transitional stage, one prefabricated crack plays a decisive role in the distribution of the surface strain field.(4) The final failure stage, the crack initiation is located in the relatively concentrated area of the strain field, and which cause the specimen damaged. For the bilateral asymmetric cracked plate specimen under direct tension, one of the cracks will propagate first, and is away from and then close to the front crack, which have great significance for the study of the propagation law of multi-crack interaction under tension stress state by using numerical simulation method.
出处
《岩土力学》
EI
CAS
CSCD
北大核心
2018年第S1期267-274,共8页
Rock and Soil Mechanics
基金
中国科学院战略先导专项(B)课题(No.XDB10030400)
中国科学院百人计划项目(No.Y323081C01)~~
关键词
拉–压转换仪
预制裂纹
直接拉伸
应变场
应力–应变曲线
裂纹路径
pressure/tension conversion device
prefabricated cracks
direct tension
strain field
stress-strain curve
crack path
