摘要
为深入认识深部含缺陷型岩石的力学行为与破坏特征,利用砂岩材料加工为不同孔径、不同孔数的立方体试样(50 mm×50 mm×100 mm),并利用GCTS RTX-3000岩石三轴仪对含孔洞型缺陷砂岩试件开展了真三轴试验,侧向应力加载到一定值后保持不变,最大主应力继续加载直至试件破坏,探究Mogi-Coulomb强度准则是否能用来描述含缺陷岩样的强度特征。试验结果表明:孔洞存在造成试件的力学参数劣化明显,试件会提前进入塑性屈服阶段,峰值强度下降明显;在加载初期,侧向应变增长速度随孔径、孔数增加而增加,而后趋于平缓,同时双孔洞、三孔洞条件下,试件扩容现象不明显;试件破坏以剪切破坏为主,单孔洞裂缝呈大"X"状延伸贯通整个试件,双孔洞为"N"状裂缝,但三孔洞条件下,孔洞周围的应力集中区形成应力屏蔽区,出现孔洞效应。
In order to deeply understanding of the mechanical behavior and failure characteristics of deep flawed rocks, the sandstone materials were processed with different diameter and number of holes into cube samples as 50 mm×50 mm×100 mm. The GCTS RTX-3000 rock triaxial instrument was used to carry out true triaxial test on the hole-defective sandstone specimens. The lateral stress remained unchanged after being loaded to a certain value, and the maximum principal stress continued to be loaded until the specimen failed. It explored whether the Mogi-Coulomb strength criterion can be used to describe the strength characteristics of rock samples with defects. The test results show that the existence of holes causes the mechanical parameters of the specimen to deteriorate significantly, and the test piece will enter the plastic yield stage in advance, and the peak strength drops significantly. In the initial stage of loading, the growth rate of lateral strain increases with the increase of the aperture and the number of holes, and then tends to be flat. However, the expansion of the specimen is not obvious under the double holes and three holes. The failure of the specimen is mainly shear failure. The crack of the single hole extends through the entire specimen in a large “X” shape, and in “N” shaped cracks of double holes. But the stress concentration area forms a stress shielding area around the holes under the three holes, and the hole effect occurs.
作者
李正一
吴斐
姜德义
肖繁
刘伟
Li Zhengyi;Wu Fei;Jiang Deyi;Xiao Fan;Liu Wei(School of Resources and Safety Engineering,Chongqing Unirersiay,Chongqing 400044,P.R.China;State Key Laboratory of Coal Mine Disaster Dynamics and Control,Chongqing University,Chongqing 400044,P.R.China)
出处
《地下空间与工程学报》
CSCD
北大核心
2022年第1期120-128,共9页
Chinese Journal of Underground Space and Engineering
基金
国家自然科学基金面上项目(52074043)。
关键词
砂岩
孔洞
真三轴试验
力学特性
sandstone
holes
true triaxial test
mechanical characteristics
