Abstract

A series of undrained cyclic axial-torsional shear tests on saturated coral sand and quartz sand under linear, circular, and heart stress paths are performed. The test results show significant differences in liquefaction characteristics for coral sand and quartz sand. A unique relationship between deviatoric strain amplitude and excess pore water pressure ratio (R_u) can be established regardless of cyclic stress paths. The termed cyclic strain path is introduced to describe the generation features of strains, and different failure patterns for various cyclic stress paths can be easily identified. Moreover, the dissipative energy required to liquefaction triggering (E_a1) of coral sand is much larger than that of quartz sand. The generation patterns of dissipative energy with R_u for both sands are almost independent of cyclic stress paths, but the correlation between the cyclic stress ratio (CSR) and the number of cycles required to liquefaction triggering (N_f) is dependent on cyclic stress paths. Using the proxy of the unit cyclic stress ratio (USR) proposed by Chen et al. (2020 Chen, G. X., Q. Wu, Z. L. Zhou, W. J. Ma, W. Y. Chen, K. Sara, and J. Yang. 2020. “Undrained Anisotropy and Cyclic Resistance of Saturated Silt Subjected to Various Patterns of Principal Stress Rotation.” Géotechnique 70 (4): 317–331. doi:https://doi.org/10.1680/jgeot.18.P.180.[Crossref], [Web of Science ®] , [Google Scholar]) instead of the CSR, the correlation between USR and N_f is independent on cyclic stress paths. A remarkable finding is that, a unique correlation between USR₁₅ and E_a1 exists for all sands considered.

摘要

在线性、圆形和心形应力路径下，对饱和珊瑚砂和石英砂进行了一系列不排水循环轴向扭转剪切试验。测试结果表明，珊瑚砂和石英砂的液化特性存在显着差异。无论循环应力路径如何，都可以建立偏应变幅值和超孔隙水压力比 ( R _u )之间的独特关系。引入术语循环应变路径来描述应变的生成特征，并且可以轻松识别各种循环应力路径的不同失效模式。此外，液化触发所需的耗散能（E _a1) 的珊瑚砂比石英砂大得多。两种砂岩的耗散能R _u的生成模式几乎与循环应力路径无关，但循环应力比 (CSR) 与液化触发所需的循环次数 ( N _f ) 之间的相关性取决于循环应力路径. 使用 Chen 等人提出的单位循环应力比 (USR) 的代理。( 2020 Chen, GX , Q. Wu , ZL Zhou , WJ Ma , WY Chen , K. Sara , and J. Yang。2020 年。“经受各种主应力旋转模式的饱和淤泥的不排水各向异性和循环阻力。” 地质技术70 (4): 317 – 331。doi：https://doi.org/10.1680/jgeot.18.P.180。[Crossref], [Web of Science ®]  , [Google Scholar] ) 而不是 CSR，USR 和N_f独立于循环应力路径。一个显着的发现是，对于所有考虑的沙子，USR ₁₅和E _{a1之间存在独特的相关性。}