级配碎石塑性变形特性及其安定行为的数值模拟

Plastic Deformation Characteristics and Numerical Simulation of Shakedown Behavior of Graded Broken Stone

应用颗粒流理论构建了级配碎石动三轴数值试验方法.通过动三轴室内试验验证了数值方法的可靠性,模拟了级配碎石在动荷载作用下的塑性变形规律.通过塑性变形累积方程探讨了级配碎石破坏临界应力与破坏临界应变.结果表明,级配碎石塑性变形数值试验结果与实际安定行为规律吻合;级配碎石的合理破坏临界应变为2.5%,在此临界应变标准下,级配碎石临界应力与围压呈现比例相关关系,比例系数为4.95;提高围压可以显著强化级配碎石的抗塑性变形性能.

A contacting constitutive model was established by using the particle flow theory and a numerical simulation of biaxial test on GBS （graded broken stone） was proposed based on PFC2D. The reliability of the numerical method was verified by dynamic triaxial laboratory test. The plastic deformation characteristics of GBS were studied by simulation. The destruction of critical stress and that of critical strain of GBS were studied by the equation of accumulative plastic deformation. The results show that numerical test results of plastic deformation law of GBS meet the actual shakedown law. The rational damage critical strain of GBS is 2.5%. Under this critical strain, the relationship between critical stress and confining pressure is proportional with a proportional coefficient of 4. 95. The increasing of confining pressure has a great effect on the resistance performance of plastic deformation of graded broken stone.