基于数字图像与数值计算的节理岩体锚固效应研究
Anchorage behaviour of specimens containing a single fissure based on digital image correlation and numerical method
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摘要: 为了研究锚杆对裂隙岩体的加固作用,通过自主研发的数字图像相关(DIC)试验技术和离散元(DEM)数值计算方法,对预置裂隙岩体试样锚固前后进行测试。从细观层次量化分析了加载过程中两类岩体(未锚固和锚固岩体)裂隙的起裂、扩展等特征,对比了数字图像测量的位移场,应变场和裂隙张开度(COD)以及数值计算得到的裂隙发育数量,区域分布和扩展方向。结果表明:基于DIC测量软件,可精确进行岩体非接触的无损测量,并且能够监测出岩体锚固这种内部隐蔽的过程;加固岩体的锚杆与裂隙交叉位置出现应变集中成核现象,定量地说明了岩体加固对裂隙的抑制作用;同时还得出岩体加固可以改变裂隙扩展类型和主裂隙发育方向。Abstract: To investigate the reinforcement effects of specimens containing a single fissure, a digital image correlation (DIC) method and a discrete element method (DEM) which can be written in house are employed to compare the results of unreinforced and reinforced specimens. The crack initiation and propagation in two types of specimens (unreinforced and reinforced specimens) are quantitatively analyzed at the mesoscopic level. The displacement fields, strain fields and crack open displacements (COD) obtained by DIC and the crack number, distribution and propagation orientation obtained by DEM are compared. The results show that the DIC method can be used to conduct non-contact nondestructive measurements of rock mass precisely and monitor the internal hidden process like anchorage behavior. The reinforcement effects of specimens are illustrated in quantity since the concentration of strain nucleation is acquired at the cross of rock bolt and pre-fissure. The reinforcement can change the type of cracks and the orientation of the main fracture.