堆石料平面应变条件下统一强度理论参数研究

 堆石料的常规三轴、方形三轴和平面应变试验对比分析表明，方形三轴试验的应力–应变曲线与常规三轴的存在显著差异，方形三轴试验对应的峰值强度高于常规三轴试验，堆石料密度较大时，应力–应变曲线呈现软化特征，存在明显的偏应力峰值。任何一组方形三轴试验对应的莫尔圆大致具有同一条公切线，平面应变试验也具有类似的强度特性，可采用直线型Mohr-Coulomb破坏准则描述堆石料的强度特性，同一种堆石料在平面应变条件下破坏时的Lode参数基本保持不变，且在数值上近似等于方形三轴试验对应内摩擦角的正弦值。在试验结果的基础上，通过双剪强度理论建立平面应变条件下堆石料的强度与方形三轴强度的关系式。对平面应变状态下堆石料强度影响因素分析表明，在本文的模型框架内，平面应变状态下的内摩擦角仅与三轴应力状态下的内摩擦角相关，而对应的黏聚力主要取决于方形三轴试验对应的黏聚力，三轴应力状态下的内摩擦角对其影响较小。通过与试验数据的对比表明，本文建立的强度关系式基本可以描述堆石料在平面应变条件下的强度特性。

UNIFIED STRENGTH THEORY PARAMETERS OF ROCKFILL MATERIAL IN PLANE STRAIN STATE

Three groups of conventional triaxial tests,square triaxial tests and plane strain tests of rockfill material are conducted to study its strength in plan strain stress state.Significant differences between conventional triaxial tests and square triaxial tests show that peak strength of latter is higher than the that of former.Especially when its density is large,the stress-strain curve shows softening characteristics and obvious peak deviatoric stress.Each Mohr circle of square triaxial tests has a common t...