The stress–strain characteristics of soil under monotonic loading conditions and the dynamic properties of soils under cyclic loading are necessary for foundation engineering, ground response analysis and soil structure interaction studies. In the absence of site/region-specific properties, it is a common practice to use representative parameters based on the index properties of soil and available standard correlations. Such correlations might be inadequate for regional soils of varying index properties. Based on monotonic and cyclic triaxial tests, this study reports the monotonic and dynamic soil properties of the prevalent soils from the northeastern region of India, namely the cohesionless, cohesive and silty-sandy soils. It is observed that monotonic response of cohesionless soil is mostly influenced by the initial relative density, while the response of cohesive and silty-sands are primarily influenced by the effective confining pressure and degree of saturation. The cyclic triaxial tests revealed that, irrespective of the soil type, the strain-dependent modulus reduction and especially the damping ratio curves are noticeably different from available standards. The study highlights the importance of identifying the site/region specific soil properties for their usage in GRA and SSI applications.

中文翻译：

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印度东北部地震活跃的印度东北部河床砂土和山坡土的单调和动力特性

单调加载条件下土壤的应力-应变特性和循环加载条件下的土壤动力特性对于基础工程，地面响应分析和土壤结构相互作用研究都是必需的。在没有特定地点/区域特性的情况下，通常的做法是根据土壤的指数特性和可用的标准相关性使用代表性参数。对于具有不同指数特性的区域土壤，这种相关性可能不足。基于单调和循环三轴试验，本研究报告了来自印度东北地区的普遍土壤的单调和动态土壤特性，即无粘性，粘性和粉质沙质土壤。观察到，无粘性土的单调响应主要受初始相对密度的影响，而粘性砂和粉砂的响应主要受有效围压和饱和度的影响。循环三轴试验表明，不论土壤类型如何，取决于应变的模量降低，尤其是阻尼比曲线均明显不同于现有标准。这项研究强调了识别特定地点/地区的土壤特性以用于GRA和SSI应用的重要性。