Strain accumulation analysis is important to understand the deformation mechanism of soil structure subjected to cyclic loading. An empirical model is a superior choice for the description of strain accumulation. However, the ambiguity and sensitivity for the physical meaning of the parameters in the empirical model hindered the understanding of the strain accumulation mechanism. Compared with conventional empirical models by directly fitting experimental data, this study proposed a new approach to formulate an empirical model of strain accumulation using the intrinsic relationship between the reloading process in cyclic loading and the monotonic loading process. All axial strain accumulation increments of silica powder during cyclic loading with constant cyclic stress amplitude were projected onto the corresponding monotonic loading stress-strain curve, and the evolution of strain accumulation was described by the projection modulus, which was regarded as an intrinsic parameter of the projection stress-strain curve. An empirical formulation for describing the connection between projection modulus and stress levels was proposed. In addition, the prediction model of total axial strain in cyclic loading was presented by combining the accurate representation of elastic and plastic moduli during primary loading. Finally, discussions on the intrinsic relation mentioned above were enhanced by presenting more experimental evidence. This paper provided novel insight into the mechanism of strain accumulation in cyclic triaxial conditions by linking strain accumulation with a unified stress-strain relation. However, limited by the triaxial stress conditions in this study, it is recommended to extend this projection method to other cyclic load tests.

应变累积分析对于理解循环荷载作用下土体结构的变形机理具有重要意义。经验模型是描述应变累积的最佳选择。然而，经验模型中参数的物理含义的含糊和敏感性阻碍了对应变累积机制的理解。通过直接拟合实验数据，与常规经验模型相比，本研究提出了一种新的方法，利用循环加载中的重载过程与单调加载过程之间的内在联系来建立应变累积的经验模型。将具有恒定循环应力幅度的循环加载过程中硅粉的所有轴向应变累积增量投影到相应的单调加载应力-应变曲线上，并用投影模量描述了应变累积的演变，该累积模量被认为是硅粉的固有参数。投影应力-应变曲线。提出了描述投影模量和应力水平之间关系的经验公式。此外，通过结合一次加载过程中弹性模量和塑性模量的精确表示，给出了循环加载中总轴向应变的预测模型。最后，通过提供更多的实验证据，加强了对上述固有关系的讨论。通过将应变累积与统一的应力-应变关系联系起来，本文为循环三轴条件下的应变累积机理提供了新颖的见解。但是，受本研究中三轴应力条件的限制，建议将该投影方法扩展到其他循环载荷测试。