基于弹性应变能岩石强度准则的建立及验证

Establishment of rock strength criteria based on the elastic strain energy and its validation

为提高强度准则计算精度与适用性,基于能量守恒与弹性应变能释放是岩石破坏的内在机制,采用理论研究与试验验证相结合的方法,阐明已有强度准则是能量型强度准则,并考虑变形对材料强度的影响,据此指出已有强度准则的计算精度与适用性较差根本原因;以弹性应变能表示的经典强度准则为基础,借鉴经验强度准则的研究方法,建立广义强度准则。研究结果表明:广义强度准则体现了弹性应变能是岩石破坏的内在机制,且是对已有强度准则的继承和发展;是一簇以引入材料参数为基础的强度准则集合,而非单一的强度准则,且参数等于0.5时广义强度准则蜕化为已有强度准则;真三轴试验验证表明,广义强度准则计算精度更高,且符合岩石的破坏机制,但经典强度准则对相应的广义强度准则计算精度有影响;进一步分析表明,广义强度准则能够定量计算岩体弹性模量、地震释放应变能及支护体系等因素对岩体稳定性影响。

Based on the fact that elastic strain energy is the internal mechanism of rock failure,the internal relationship between elastic strain energy and abrupt structural failure in the process of rock deformation is firstly discussed,and it is pointed out that the strength criteria are essentially the type of strength criteria of elastic strain energy,and the fundamental reason for the poor calculation accuracy and applicability of these strength criteria is that the Poisson's ratio of rock failure under any stress level is always regarded as 0.5.A material parameter is introduced,and the generalized strength criterion is established based on the classical strength criterion.The results show that the generalized strength criterion is a set of strength criteria with the introduced parameter as the parameter,rather than a single strength criterion,and the generalized strength criterion degenerates into the corresponding strength criterion when the introduced parameter is equal to 0.5.True triaxial test results show that the calculation accuracy of generalized strength criterion is higher and more suited to the failure mechanism of rock,but classical strength criterion has influence on the calculation accuracy of corresponding generalized strength criterion.Further discussion shows that the generalized strength criterion can directly reflect the influence of elastic modulus of rock mass,strain energy released by earthquake and supporting system on the stability of rock mass.The generalized strength criterion breaks through the assumption that the Poisson's ratio is equal to 0.5 in the case of material failure in the classical strength criterion,which is of great significance for the accurate quantitative analysis of material failure characteristics.