作　　者： (杨殷豪）; (李忠友）;

机构地区： 西南大学工程技术学院

出　　处： 《青岛科技大学学报（自然科学版）》 2017年第S1期154-157,164,共5页

摘　　要： 损伤变量及其演化方程是损伤本构理论研究的核心问题,当前岩土材料的损伤演化方程多是通过经验假定或试验拟合的方法得到的,缺少必要的理论依据。本研究定义损伤变量为材料受荷变形过程中的能量耗散量与破坏时的临界能量耗散量之比,结合Lemaitre应变等价性假设,从材料损伤过程中的能量平衡原理出发,推导了具有理论依据的损伤演化方程表达式,从而建立了适用于脆性岩土材料的广义拉伸损伤本构模型。通过试验和数值计算结果对比表明模型能够较好的反映单轴拉伸过程中的应力应变关系和应力跌落现象。对不同加载条件下的应力应变关系计算表明:广义拉伸状态下,脆性岩土材料的抗拉强度随侧向压应力的增大而减小,随侧向拉应力的增大而先增加后减小。 Damage evaluation equation is the key problem in the research on the damage constitutive theory,but most of current damage evaluation equations are obtained by the methods of experience supposition or examination fitting,there is a lack of theoretically basis.Damage is an irreversible process of energy dissipation,so the damage variable is defined as the ratio of accumulated dissipating energy to fracture energy.Through the principle of conversation of energy and Lemaitre equivalent strain assumption,a damage evaluation equation is established,and then a generalized tension damage constitutive model for brittle geotechnical materials is established in the paper.Comparison of the proposed model and experimental results shows that the model can reflect the stress-strain relation and stress drop under uniaxial tension sate.The numerical calculations of stress-strain relation under different loading condition show that tensile strength decreases with increasing lateral compression stress,increases with increasing lateral tension stress at low lateral stress state and decreases with increasing lateral tension stress at high lateral stress state.

关 键 词： 岩土材料 能量耗散 广义拉伸 损伤 本构模型