Abstract The mechanical characteristics of ultra-high asphalt concrete core rockfill dams (UACCRDs) at different periods is investigated via Rankine’s earth pressure theory, and a shear safety control standard for UACCRDs is proposed. The reasonable material parameters of the asphalt concrete core (ACC) and transition material that independently and comprehensively satisfy the shear safety control standard are back-calculated. The engineering measures that reduce the stress level (shear stress) of the ACC are given. Moreover, the engineering measures (straight asphalt concrete core rockfill dams (SACCRDs) are designed as curved asphalt concrete core rockfill dams (CACCRDs)) that reduce the tensile stress of the ACC are proposed. Based on the theory of the straight beam and curved beam on Winkler elastic foundation, the simplified mechanical models of straight asphalt concrete core (SACC) and curved asphalt concrete core (CACC) are established. The improvement effect of CACC that reduces tensile stress is also investigated. The results show that the following value ranges of the internal friction angle, cohesion of ACC and the internal friction angle of transition material for the suitable construction of UACCRDs are recommended: φa ≥ 30.5°, Ca ≥ 0.25 MPa and φt ≤ 43.5° (h = 200 m), with the growth gradient adjusted by 0.5%, 1.5% and −0.5%/25 m. The stress level of ACC can be obviously reduced by increasing the internal friction angle and cohesion of ACC, and reducing the internal friction angle of transition material. The simplified mechanical models of SACC and CACC can estimate the force and deformation characteristic of the ACC (SACC and CACC) well. The CACC can significantly reduce tensile stress to a level approximately 42.8% lower than that of SACC.

中文翻译：

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超高沥青混凝土核心堆石坝关键技术探讨

摘要 运用兰金土压力理论研究了超高沥青混凝土芯堆石坝(UACCRDs)不同时期的受力特性，提出了UACCRDs的剪切安全控制标准。对独立综合满足剪切安全控制标准的沥青混凝土芯（ACC）和过渡材料的合理材料参数进行反算。给出了降低ACC应力水平（剪切应力）的工程措施。此外，提出了降低ACC拉应力的工程措施（将直式沥青混凝土芯堆石坝（SACCRDs）设计为弯曲沥青混凝土芯堆石坝（CACCRDs））。基于温克勒弹性地基上的直梁和弯梁理论，建立了直沥青混凝土芯（SACC）和弯曲沥青混凝土芯（CACC）的简化力学模型。还研究了降低拉伸应力的 CACC 的改进效果。结果表明，适合构造UACCRDs的内摩擦角、ACC的内聚力和过渡材料的内摩擦角推荐如下取值范围：φa≥30.5°，Ca≥0.25MPa和φt≤43.5°（h = 200 m)，生长梯度调整为 0.5%、1.5% 和 -0.5%/25 m。增加ACC的内摩擦角和内聚力，减小过渡材料的内摩擦角，可以明显降低ACC的应力水平。SACC和CACC的简化力学模型可以很好地估计ACC（SACC和CACC）的受力和变形特性。