Abstract Rational evaluation of the long-term performance of large-scale foundations, tunnels and natural slopes located in seismically active areas necessitates accurate assessment of the strength and deformation characteristics of bounded geomaterials, such as natural rocks and cemented soils, under creep and cyclic loading conditions. In the present study, a unique approach for examining the induced instantaneous loading/strain rates during unconfined creep and cyclic loading was adopted to unveil the effects of creep and cyclic loading on the mechanical behaviour of laboratory-produced bounded geomaterial, namely Gypsum Mixed Sand (GMS). At first, a series of unconfined monotonic tests at six different strain rates ranging from 5.3E+0 to 2.1E-5%/min were conducted on GMS. Subsequently, the mechanical behaviour of the GMS was examined under unconfined creep/sustained loading at four different stress levels. Further, these results were compared with a number of unconfined cyclic loading tests performed at different stress amplitudes. Identical patterns of the variations of axial strain accumulation and instantaneous strain rates were observed during the creep and cyclic loading. Based on the relationships between the failure stress/strain and the corresponding instantaneous strain rate, the mechanical behaviour of the GMS specimens subjected to creep and cyclic loading was found to be similar to each other, and was distinctively different than those under monotonic loading condition.

中文翻译：

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考虑瞬时应变率影响的有界岩土材料在蠕变和循环载荷作用下的力学行为试验研究

摘要 对位于地震活动区的大型地基、隧道和天然边坡的长期性能进行合理评价，需要准确评估天然岩石和胶结土等有界岩土材料在蠕变和循环荷载作用下的强度和变形特性。使适应。在本研究中，采用了一种独特的方法来检查无侧限蠕变和循环加载过程中的诱导瞬时加载/应变率，以揭示蠕变和循环加载对实验室生产的有界地质材料（即石膏混合砂）力学行为的影响。 GMS）。首先，在 GMS 上以 5.3E+0 至 2.1E-5%/min 的六种不同应变率进行了一系列无侧限单调试验。随后，在四种不同应力水平下，在无侧限蠕变/持续载荷下检查了 GMS 的机械性能。此外，将这些结果与在不同应力幅度下进行的许多无侧限循环载荷试验进行了比较。在蠕变和循环加载期间观察到轴向应变累积和瞬时应变率变化的相同模式。基于破坏应力/应变与相应瞬时应变率之间的关系，发现 GMS 试样在蠕变和循环加载下的力学行为彼此相似，并且与单调加载条件下的力学行为明显不同。将这些结果与在不同应力幅度下进行的许多无侧限循环载荷试验进行了比较。在蠕变和循环加载期间观察到轴向应变累积和瞬时应变率变化的相同模式。基于破坏应力/应变与相应瞬时应变率之间的关系，发现 GMS 试样在蠕变和循环加载下的力学行为彼此相似，并且与单调加载条件下的力学行为明显不同。将这些结果与在不同应力幅度下进行的许多无侧限循环载荷试验进行了比较。在蠕变和循环加载期间观察到轴向应变累积和瞬时应变率变化的相同模式。基于破坏应力/应变与相应瞬时应变率之间的关系，发现 GMS 试样在蠕变和循环加载下的力学行为彼此相似，并且与单调加载条件下的力学行为明显不同。