A series of cyclic direct simple shear tests are performed to investigate the liquefaction resistance of sandy soils from Christchurch, New Zealand. The study focuses on the combined effects of soil density and fines content on liquefaction resistance of sandy soils. Two sands, a non-plastic silt, and their mixtures prepared at different fines contents are tested at two sets of relative densities. Test specimens are reconstituted using a procedure for water sedimentation, yielding soil fabric and soil structure resembling those of fluvial soil deposits. Differences are observed between the two host sands in the sensitivity of the cyclic liquefaction resistance to changes in relative density. Differences are also seen in the effects of the addition of fines to the liquefaction resistances of the two sands. Monotonic undrained direct simple shear tests are employed to explore an interpretation of the liquefaction resistance of the tested soils within the critical state framework. The state-concept interpretation provides more consistent quantification of the effects of initial state on the liquefaction resistance; however, the relationship between the state parameter and liquefaction resistance is soil dependent. The results of cyclic direct simple shear tests for soils containing up to 30% fines show reasonably consistent liquefaction resistances relative to estimates from empirical CPT-based liquefaction triggering relationships.

进行了一系列循环直接简单剪切试验，以研究来自新西兰基督城的沙质土壤的抗液化性。该研究集中于土壤密度和细度对砂土抗液化性的综合影响。在两组相对密度下测试了两种沙子，一种非塑料淤泥及其以不同细粉含量制备的混合物。使用用于水沉降的程序重建试样，产生类似于河流土壤沉积物的土壤织物和土壤结构。观察到两种基质砂在循环液化阻力对相对密度变化的敏感性方面存在差异。在两砂的抗液化性上添加细粉的效果也有所不同。单调不排水直接简单剪切试验用于探索对临界状态框架内被测土壤的抗液化性的解释。状态概念的解释可以更一致地量化初始状态对抗液化性的影响。但是，状态参数与抗液化性之间的关系取决于土壤。相对于根据基于CPT的经验性液化触发关系所作的估算，对含30％细粉的土壤进行的循环直接简单剪切试验的结果表明，其抗液化性具有合理的一致性。状态概念的解释可以更一致地量化初始状态对抗液化性的影响。但是，状态参数与抗液化性之间的关系取决于土壤。相对于根据基于CPT的经验性液化触发关系所作的估算，对含30％细粉的土壤进行的循环直接简单剪切试验的结果表明，其抗液化性具有合理的一致性。状态概念的解释可以更一致地量化初始状态对抗液化性的影响。但是，状态参数与抗液化性之间的关系取决于土壤。相对于根据基于CPT的经验性液化触发关系所作的估算，对含30％细粉的土壤进行的循环直接简单剪切试验的结果表明，其抗液化性具有合理的一致性。