岩石室内单轴压缩试验位移加载速率的研究

Displacement Loading Rate of Rock-like Specimen Under Uniaxial Compress Test

岩石物理力学参数的确定对于实际工程的施工具有十分重要的意义。随着刚性伺服试验机的普及,人们逐渐意识到,相对于负荷加载,采用位移加载方式获得的岩石室内单轴抗压强度更具有可靠性。但是,有关规范中仅给出了负荷加载速率而并未给出明确的位移加载速率。为了寻找到岩石室内单轴压缩试验的最佳位移加载速率,利用石膏砂浆制成类岩石试件,分别模拟泥岩和泥质砂岩,分析类岩石试件在位移加载方式和负荷加载方式下的力学效应及破坏形态。研究发现:位移加载速率在0.02mm/s^0.05 mm/s之间时,通过位移加载方式得到的类岩石试件的单轴抗压强度与通过负荷加载得到的单轴抗压强度最为接近。试件较软时,位移加载速率应适当降低,约为0.02 mm/s,试件较硬时,加载速率适当增高,约为0.05 mm/s。

The physics-mechanical parameters of rock is important to engineering practices. With the development of rigid servo tester,people realized that compared to stress loading,the strength obtained by displacement loading is more reliable. However,no explicit displacement loading rate is given in the specification. In order to find the suitable displacement loading rate of rock mass,in this paper we choose gypsum and sand to make specimen and simulate the mudstone and argillaceous sandstone respectively. The strength and failure mode under two different loading method were analyzed.The results show that the displacement loading rate is between 0.02 mm/s and 0.05 mm/s,and the mechanical properties of specimen obtained by displacement loading are the closest to those obtained by stress loading. If the material is weak the loading rate should be reduced to nearly 0.02 mm/s,when the material is hard,the loading rate should be raised to nearly 0.05 mm/s.