炭质板岩轴向与侧向蠕变规律研究

Study on the law of axial and lateral creep of carbonaceous slate

炭质板岩在岩土工程中普遍存在,且具有各向异性的特点。为研究其蠕变规律,首先采用岩石三轴流变试验机对自然状态和泡水30 d的炭质板岩进行单轴压缩试验,获得其瞬时强度分别为62.4和54.2 MPa,再基于瞬时强度,设置应力水平依次为瞬时强度的60%、70%、80%、85%及90%进行单轴分级加卸载蠕变试验。研究结果表明:蠕变量及蠕变速率随应力水平增大而增大;水在炭质板岩孔隙裂隙中流动,其对炭质板岩的长期损伤劣化作用使得孔隙裂隙增大,导致蠕变量及蠕变速率显著增大,尤其对轴向蠕变影响更明显,因此轴向蠕变量及蠕变速率比侧的向大;水的作用显著地增大了炭质板岩瞬时塑性应变及黏弹性应变,该现象在轴向比侧向表现更明显。

Carbonaceous rocks are common in geotechnical engineering and have the characteristics of anisotropy. For the study of carbonaceous slate creep law, three rheological test machine for rock in nature and soaked for 30 days carbonaceous slate uniaxial compression tests are performed to obtain the instantaneous strength, 62.36 MPa and 54.23 MPa respectively. Based on the instantaneous strength, the uniaxial loading and unloading creep tests are carried out. The stress level is designed in turn to be 60%, 70%, 80%, 85% and 90% of the instantaneous strength. The results show that creep and creep rate increase with the increase of stress level. In addition, water flows in the pores and pores of carbonaceous slates. For a long time, the damage and deterioration of carbonaceous slate resulted in the increase of pore fissure. The creep and creep rate increased significantly, especially in axial creep. At the same time, the water significantly increased the instantaneous plastic strain and viscoelastic strain of the carbonaceous slate, and the axial strain of the carbonaceous slate should be changed obviously.