V形裂隙类岩石材料单轴压缩光弹性试验

Uniaxial Compression Experiment of Rock-like Materials with V-Shaped Cracks by Photoelasticity

天然岩体内交叉裂隙按几何形状可分为X形、T形与V形等,其中V形裂隙可以近似看作前两者在“短交叉”情况下的特殊形式,其裂纹扩展破坏规律与其他两种形式存在显著不同。为了探究V形裂隙在荷载作用下对于岩体损伤破坏规律的影响,开展了不同裂隙倾角的类岩石材料单轴压缩光弹性试验,根据应力-光学定律计算试件表面的应变场,分析V形裂隙岩体的损伤破坏规律。结果表明,岩体强度随裂隙倾角增加而增加,但增长速度不断减小,并建立了裂隙倾角与单轴强度的拟合曲线;V形裂隙岩体裂纹扩展首先发生在非交叉端,随后在交叉端产生沿加载轴向的裂纹,当裂隙倾角不大于45°时,随着荷载增加在两个非交叉端之间也会产生宏观裂纹。

The cross-cracks in the rock can be divided into X-shaped,T-shaped and V-shaped,etc.Among which,the V-shaped cracks can be approximated as a special form of the former two types.Because of sharp point in the intersection of cracks,the failure propagation is significantly different from the others.To study the crack regulation of the rock mass with V-shaped cracks under load,uniaxial compression photoelastic experiments of rock-like materials with different fracture angles were carried out.The full-field stress of the specimen surface was calculated based on the optical-stress law.The results show that the strength of the rock masses increases with the raise of the fracture angle,but the growth rate decreases continuously.Besides,the fitting curve of the dip fractures angle and the uniaxial strength is established.During uniaxial loading process,the damage firstly occurs in the non-intersection end.Then the damage occurs in the intersection end and expands on the loading direction.If the fracture angle is not more than 45°,macroscopic cracks are also generated between the two non-intersected ends.