Particle characteristics (particle shape and size), along with relative density, significantly influence the frictional characteristics and liquefaction behavior of granular materials, particularly sand. While many studies have examined the individual effects of particle shape, gradation, and relative density on the frictional characteristics and liquefaction behavior of sand, they have often overlooked the combined effects of these soil parameters. In this study, the individual effect of these three soil parameters on the strength characteristics (angle of internal friction) and liquefaction resistance has been quantified by analyzing the data available in the literature. A novel dimensionless parameter, the 'packing index (\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\alpha $$\end{document}),' was developed to account for the bulk characteristics (relative density - RD) and grain properties (gradation, represented by the coefficient of uniformity (\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$C_u$$\end{document}), and particle shape represented by the shape descriptor regularity (\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\rho $$\end{document})) of the granular soils. Through statistical analysis, a power law-based equation was proposed and validated to relate the cyclic resistance ratio (CRR) and angle of internal friction (\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\phi $$\end{document}) with the packing index. Finally, an approach to assess the liquefaction resistance was detailed considering the intrinsic soil parameters, aiming to bridge the gap between field observations and laboratory analysis to facilitate a comprehensive understanding of soil behavior under cyclic loading.

Despite significant advances in laboratory testing in recent decades, geotechnical designs that incorporate data from in-situ testing remain predominant worldwide. One of the most commonly employed techniques for correlating soil mechanical properties is the standard penetration test. However, while this test provides valuable information for identifying soil strata and offering general descriptions of soil characteristics, its correlation with shear strength parameters has several limitations that are often overlooked. In this article, we aim to i) present a critical literature review concerning the applicability of correlations between the undrained shear strength of fine-grained soils and standard penetration test data; ii) estimate the uncertainties associated with the adoption of these empirical correlations, which are frequently disregarded in engineering practice; iii) present simulation results from typical slope stability analyses, taking into account the uncertainties associated with the estimation of the undrained shear strength. The findings of our study suggest that geotechnical engineers should exercise caution when using such simplified equations, as they often lead to underestimations or overestimations of the stability of geotechnical structures.

Seismic Site Characterization involves the qualitative assessment of top-soil properties that have the capability of amplifying the generated earthquake ground motions. The geotechnical properties of topsoil refer to the top 30m subsurface profile which plays a vital role in seismic microzonation and Ground Response Analysis (GRA) studies. Among various geotechnical parameters, shear-wave velocity (Vs) of the top 30 m subsurface is mainly linked to seismic site characterization and amplification studies. The average shear-wave velocity of the top 30 m subsurface, Vs(30), has been used for seismic site classification in accordance with the National Earthquake Hazard Reduction Program (NEHRP) and various building codes. In this study, an attempt has been made to retrieve the geospatial variation of average shear-wave velocity for Coimbatore city using the active Multichannel Analysis of Surface Waves (MASW) test which is one of the non-destructive geophysical tests. To retrieve the spatial distribution of shear-wave velocity (Vs), the test was carried out at 35 locations in the vicinity of important structures, schools, colleges, and hospitals within the city. The seismic records have been acquired in the field and analyzed using the winMASW software. From the one-dimensional MASW test, the study area has an average Vs(30) in the range of 640 m/s to 909 m/s and has been classified as site-class BC (soft rock) according to NEHRP standards. These test results have been validated using the collected SPT bore log data from various locations, including 40 sites in the vicinity of the conducted MASW tests. The site-specific correlation between the shear-wave velocity (Vs) and the corrected SPT N- Value, N1(60), and between Vs and shear modulus (G) have been developed for Coimbatore city with a regression coefficient of 0.79 and 0.83 respectively. From the fundamental site period map, the study area has a site period in the range of 0.1 to 0.2 s, which indicates that 1to 2- storey buildings that are densely distributed throughout the city may lead to damage in case of probable future earthquakes. This study bridges the connectivity from the evaluated bedrock acceleration using the Seismic Hazard Analysis (SHA) and provides insights for evaluating surface acceleration using GRA studies.

Mapping superficial and subsurface conditions play an important role in analysis and design of geotechnical structures and facilities. The mechanical parameters of sandy clays soil have significant spatial variability or heterogeneity due to the complex deposition process of soil, leading to the high uncertainty of the quantifications of its parameters. Therefore, understanding the spatial variability of the parameters is an important approach to reduce uncertainty. This paper deals with the characterization of spatial variability of soil interface in Japoma-Cameroon, using standard penetration test, cone penetration tests and pressuremeter test data. The vertical and horizontal variability was taken into account, and the data are analyzed within a heterogeneous layer using Bayesian kriging and random field theory, probability density function, coefficient of variation (COV) and scale of fluctuation (theta v). The study reveals that lognormal and normal distributions, respectively, fit the histograms of NSPT, qc, Em and Pl, with all parameters increasing with depth. The COV values, ranging from 30.10 to 88.75%, reflect significant site heterogeneity. Parameters N, qc and Em are adjusted by the exponential cosine autocorrelation function, while Pl uses the exponential sinusoidal function. Fluctuation scales theta v values vary from zero to 1.98 m vertically, with horizontal scales extending up to hundreds of meters, indicating the influence of geological anisotropy. Semivariograms show limitations in small-scale structure capture, potentially overestimating the nugget effect. The exponential model's predictions are reliable for site microzonation, subsoil bearing capacity analysis and other geotechnical parameters based on NSPT.

India's passenger traffic primarily relies on the road network for commuting. As a result, the demand for transport infrastructure has led to rapid growth in road construction across the country. California Bearing Ratio (CBR) tests measure strength of subgrade soil, which is essential for pavement design. In practice, the CBR value is often estimated through index and strength properties of soil, since it is easier as compared to the conventional time-consuming laboratory CBR testing. Over the years, a lot of efforts has been taken for developing CBR from index and strength properties correlation equations, most of which are based on regression analysis. Moreover, most of the correlation equations developed are based on a wide dataset compiled from different regions, which makes them incapable of accounting for the spatial variability of soil. This study presents a quick approach to estimate onsite CBR values using sensor acceleration data, avoiding time-consuming laboratory tests. An Arduino Uno sensor collected data for 19 locations in Dhule district, Maharashtra was used in present study. The developed CBR equations using sensor data showed a strong correlation with conventional regression equations and experimental results.

The 2017 Pohang earthquake [the second largest local magnitude (M-L) of 5.4 since 1978] caused significant damage: numerous sand boils and a few building settlements were observed in rice paddies and residential areas, respectively, representing unprecedented case histories of earthquake-triggered liquefaction and cyclic softening. This study evaluated liquefaction triggering and cyclic softening potentials using three in situ tests [standard penetration test (SPT), cone penetration test (CPT), and downhole (DH) test for shear wave velocity (V-S)] and laboratory tests (grain size and soil indices) for the observed sand boils and building settlements. We selected six sites, four of which had sand boils (Sites 1, 2, 3, and 4), and two of which had experienced building settlements that may have resulted from cyclic softening (Sites 5 and 6). The SPT, CPT, and V-S adequately assessed liquefaction triggering [i.e., factor of safety (FS)2 at all depths. The site-specific cyclic stress ratio through the maximum shear stress ratio computed from site response analysis appropriately evaluated the liquefaction triggering and cyclic softening at the considered sites. The results of the soil index test are consistent with the liquefaction and cyclic softening susceptibility criteria for fine-grained soils. We publicly provide the field and laboratory measurements in this study to enrich case history data on liquefaction and cyclic softening induced by intermediate-size earthquakes (e.g., a moment magnitude, M<6), which might significantly contribute to geotechnical earthquake engineering and engineering geoscience communities

Liquefaction of sub-soil is a phenomenon in which partially saturated or saturated loose cohesionless sub-soil, especially loose fine sand, significantly lose their strength and stiffness in response to applied stresses. It occurs generally during earthquake shakings because of the generation of surplus pore water pressure, causing it to lose its effective stress and act like a liquid. Essentially, prediction of the liquefaction severity accurately is very important for liquefaction-prone sites for different seismic conditions. All the structures that are constructed on sub-soil are susceptible to liquefaction and can get damaged as a result of earthquake ground motion. Since earthquakes are one of the most disastrous events, analysis for sub-soil needs to be conducted to understand the soil behavior and its stability against liquefaction at different sites. There are several simplified techniques to assess liquefaction potential on the basis of standard penetration test (SPT), cone penetration test (CPT), and shear wave velocity (Vs) test. In this paper, simplified liquefaction analysis has been carried out based on SPT data for 10 sites in Bahraich District situated in Uttar Pradesh. Liquefaction potential index (LPI) has been calculated and the level of liquefaction severity is classified. It was observed that out of 10 site that have been evaluated 5 had moderate to high severity; while, the remaining 5 sites had high to very high severity. The classification helped in preliminary comprehension of the liquefaction susceptibility of the sites selected for construction.

In the present study, four different SPT-based methods for liquefaction assessment namely Seed and Idriss (S-I), Tokimatsu and Yoshimi (T-Y), Japan Road Association (JRA), and Chinese code for Seismic Design of Buildings (CSDB) method has been discussed in detail. The present study compares the liquefaction potential estimation of S-I, T-Y, and JRA methods, respectively. The S-I method predicts 9.29 and 3.42 times higher liquefaction occurrence compared to JRA and T-Y methods respectively. Different damage indices such as liquefaction potential index (LPI), liquefaction risk index (LRI), and ground settlement have been evaluated for an earthquake magnitude of 7.5 on the Richter scale and peak ground accelerations varying in the range of 0.1-0.36 g respectively. LRI provides a more precise estimation of the liquefaction damages compared to LPI. The gradation of liquefiable soil has been presented and compared with the established limits of liquefiable soils.

Some soil characteristics, such as the shear wave velocity, the shear modulus, the Poisson ratio, and the porosity, affect how clay soils behave. The soil design parameters under loading, such as soil liquefaction induced by dynamic earthquake loading, employ the shear wave velocity and shear module with modest stress. In order to understand the pore saturation, the Poisson ratio and seismic velocity ratio are also utilized. Additionally, one of the most crucial physical characteristics for assessing permeability at the base of any engineering structure, resolving consolidation issues that may arise at the foundation of an engineering structure, and influencing the deformation behavior of soils is soil porosity. Predicting the porosity of clay soils is a crucial first step in tackling engineering and environmental issues that may arise in the soil after an earthquake or not. With the use of dynamic soil metrics such as seismic velocities, shear modules, bulk modules, seismic velocity ratios, and Poisson ratios, the current work aims to estimate soil porosity. Seismic refraction was used by various studies in the past to conduct in-situ geophysical research. The lithological characteristics of the soil (such as the grain size, shape, type, compaction, consolidation, and cementation of the grains) and the physical characteristics of the soil (such as porosity, permeability, density, anisotropy, saturation level, liquid-solid transition, pressure, and temperature), as well as the elasticity characteristics of the soil (such as shear modulus (G), bulk modulus (K), Young modulus (E), Poisson ratio (mu) and Lame constants (lambda) all have an impact on seismic waves passing through a medium.

In the recent past, liquefaction is considered as one of the major geotechnical hazards in worldwide caused due to earthquakes in saturated fine sand deposits. Liquefaction of soil results in catastrophic damages to life and property as well. Keeping this in view, prior anticipation of occurrence of liquefaction is required to safeguard the infrastructure and life against the adverse effects of liquefaction, especially in coastal areas where abundant saturated sand deposits are present. This study has been carried out to determine the evaluation of liquefaction potential and liquefaction potential indices in the selected areas of Visakhapatnam city by estimating the factor of safety based on field SPT N values as per IS 1893 Part 1 2016 and Idriss & Boulanger (2008) methods. Based on the study, it was concluded that all the study areas, other than study area 4, are not prone to liquefaction under the considered magnitudes of earthquakes with respect to present seismic zoning 2. However, the subsoil profiles of all study areas indicated high risks against liquefaction, corresponding to seismic zones 4 and 5.