Monotonic and dynamic properties of riverbed sand and hill-slope soils of seismically active North-east India for ground engineering applications

Shiv Shankar Kumar,A Murali Krishna,Arindam Dey

doi:10.1186/s40703-020-00116-1

Abstract

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.

Highlights

Monotonic and dynamic soil properties are extremely important parameters for any ground engineering applications such as soil-structure interaction, foundation engineering, slope stability and seismic ground response analyses
Such phenomenon in loose sandy soils might lead to the possibility of static liquefaction if there is a significant rise in the excess pore water pressure (PWP)
It is concluded that under monotonic loading, the shear stiffness of the cohesionless BS soil is predominantly influenced by initial relative density of the prepared sample than the applied confining pressure or displacement loading rate

Summary

Introduction

Monotonic and dynamic soil properties are extremely important parameters for any ground engineering applications such as soil-structure interaction, foundation engineering, slope stability and seismic ground response analyses. Monotonic shear tests were performed on SBS specimens (reconstituted at Dr = 30%, 60% and 90%, and σ′c = 100 kPa) at different loading rates ranging between 0.005 and 5.0 mm/min.

Results

Conclusion