预制交叉裂隙花岗岩强度特征试验

Experimental on Strength Characteristics of Granite with Pre-existing Cross Cracks

为探究交叉裂隙对岩石强度的影响,通过制备含不同角度主次交叉裂隙的花岗岩试件,对其进行单轴压缩试验。结果表明:主裂隙平行于加载方向时,试件的峰值强度与起裂强度普遍较大且均随裂隙角度增加而呈降低趋势,主裂隙对试件强度的影响非常小,试件的破坏主要受次裂隙控制;主裂隙不平行于加载方向时,试件的峰值强度与起裂强度相对较低,次裂隙的角度变化一定程度上会使岩石试件的强度产生波动,但从主裂隙相同组试件的平均强度上看,其引起的变化很小;主裂隙相同时,随次裂隙角度的变化,峰值强度与起裂强度的变化波动规律大致相同,成正相关关系;主裂隙相同组试件平均的峰值强度与起裂强度均随裂隙角度增加呈降低趋势,同单裂隙试件相对应的峰值强度与起裂强度相接近。

In order to explore the influence of cross cracks on rock strength,granite specimens with primary and secondary cross cracks at different angles were prepared and subjected to uniaxial compression tests.The results show that when the main fracture is parallel to the loading direction,the peak strength and the initiation strength of the specimen are generally large and decrease with the increase of fracture angle.The main fracture has little influence on the specimen strength,and the failure of the specimen is mainly controlled by the secondary fracture.When the main fracture is not parallel to the loading direction,the peak strength and initiation strength of the specimen are relatively low,and the strength of the rock specimen will fluctuate to some extent due to the angle change of the secondary fracture,but from the average strength of the specimens in the same group of main fractures,the change caused is very small.When the main fissures are the same,with the change of the angle of the secondary fissures,the variation and fluctuation rules of the peak strength and the initiation strength are approximately the same,forming a positive correlation.The average peak strength and crack initiation strength of the same group of specimens with the main crack decrease with the increase of crack angle,and the peak strength corresponding to the single crack specimen is close to the crack initiation strength.