砂岩拉伸过程中的能量耗散与损伤演化分析

ANALYSIS OF ENERGY DISSIPATION AND DAMAGE EVOLUTION OF SANDSTONE DURING TENSILE PROCESS

岩石作为一种非均质的复杂地质材料,其力学响应表现出明显的非线性和各向异性特点。借助先进的试验测试系统,可以对岩石进行直接拉伸试验,从而在现有大量压缩试验的基础上进一步完善对岩石基本力学行为的研究。通过砂岩的循环拉伸试验研究发现,拉伸过程中外载所做的总功除了引起岩石弹性变形能的增大外,还有一部分被耗散掉从而导致岩石发生不可逆的损伤。在对能量耗散进行分析的基础上,可以建立岩石的损伤演化方程,并通过试验测定相应的参数指标。试验研究和理论分析表明,基于能量耗散分析建立的岩石损伤演化方程可以较好地描述岩石的损伤演化过程。

As a kind of complex inhomogeneous geological material, the mechanical response of rock behaviors distinct nonlinear and anisotropical characteristics. Direct tensile test of rock can be conducted by means of the advanced test system, accordingly the basic mechanical behavior of rock can be further studied in addition to the current numerous compression tests. It is observed during the cyclic tensile test of sandstone that the whole work of external applied load results in not only the increase of elastic deformation energy but also the irreversible damage because it is partly dissipated. Based on the analysis of such energy dissipation, a damage evolution equation of rock can be constructed： and the corresponding parameters can be determined through tests. Experimental study and theoretical research demonstrate that the damage evolution equation of rock based on the analysis of energy dissipation can well characterize the damage evolution process of rock.