Moderate-size earthquakes, and the presence of water saturated soil in the near surface can trigger the liquefaction geohazard causing buildings to settle / tilt or collapse, damaging bridges, dams, and roads. A number of paleo-seismic research have focused on the Himalayan area as a potential site for liquefaction. The present study site is in the south of the tectonically active Himalayan foothills and lies in earthquake Seismic Zone III. Therefore, the region can experience earthquakes from nearby regions and can potentially damage civil infrastructures due to liquefaction. The objective of this paper is to determine the susceptibility of alluvial soil deposits to liquefaction for seismic hazard and risk mitigation. Liquefaction geohazard study of alluvial deposits was carried out using shear wave velocity (Vs) profiling. Preliminary assessment of the soil is made by building the average shear wave velocity map up to 30 m depth (Vs30) and by constructing the corrected shear wave velocity (V-s1) maps. It was observed from the Vs30 map that a major portion of the studied area lies in Site Class CD and only a small portion lies in Site Class D. Moreover, it is also noticed from the V(s1 )map that a smaller of the area has V(s1 )lower than the upper limit of V-s1(& lowast; )(215 m/s) below which liquefaction may occur. The region showing lower values of V(s1 )is further examined for liquefaction hazard as per the guidelines given by Andrus et al. (2004). Resistance of the soil to liquefaction, stated as cyclic resistance ratio (CRR), and the magnitude of cyclic loading on the soil induced by the earthquake shaking, stated as cyclic stress ratio (CSR) are computed for the area. Several maps of factor of safety (FS) for different depths are prepared by taking the ratio of CSR and CRR. When FS < 1, the soil is considered prone to liquefaction. Furthermore, susceptibility of soil to liquefaction against different peak horizontal ground surface acceleration (PHGSA) and varying depth of water table is also evaluated in terms of factor of safety. It is observed from this study that for lower levels of PHGSA (up to 0.175 g) the soil can be considered safe. However, the soil becomes more vulnerable to liquefaction when PHGSA is above 0.175 g and with rising water table. The comparison of the factor of safety (FS) obtained using the SPT-N method and the Vs-derived approach shows consistent results, with both methods confirming the absence of liquefaction in the studied soil layers.

Rock phosphate is a non-renewable primary source for mineral phosphorus (P) fertilizers that intensive agriculture is highly dependent on. To avoid P fertilizer shortages and limit negative environmental impacts, circular economy approaches are needed with recycling-derived fertilizer (RDF) applications. Here, a grassland field trial was established with two struvites (potato wastewater, municipal wastewater) and two ashes (poultry-litter ash, sewage-sludge ash) at a P application rate of 40 kg P ha(-1) (replicates n = 5). The impact of these RDFs on the soil microbial P cycling community was compared to conventional mineral P-fertilizer and a P-free control. Topsoil samples were taken directly after Lolium perenne grass cuts at months 3, 5 and 15. Cultivable phosphonate and phytate utilizing bacteria, potential acid and alkaline phosphomonoesterase activity, and phoC and phoD copy numbers responded stronger to seasonal effects than treatment effects. No significant overall effect of the fertilizer application was detected in the beta-diversity of the bacterial and fungal communities after 15 months, but individual phylogenetic taxa were affected by the treatments. The ash treatments resulted in significantly higher relative abundance of Bacillota and Rokubacteria and lower relative abundance of Actinomycetota. Sewage-sludge ash had significantly lowest abundances of genera Bacillus and Bradyrhizobium that are well known for their P cycling abilities. The struvite RDFs either positively influenced the P cycling microbial community as demonstrated through higher tri-calcium phosphate solubilizing capabilities (month 3), or were similar to the superphosphate and P-free treatment. From a soil-microbial health perspective, the presented findings indicate that struvites are a suitable substitute for superphosphate fertilizers.

In recent years, microplastic (MPs) and pesticide pollution have become prominent issues in the field of soil pollution. This research endeavored to assess the impact of ultraviolet radiation (UV) on the characteristics of microplastics, as well as investigating the toxicological effect on earthworms (Eisenia fetida) when subjected to the dual stressors of microplastics and acetochlor (ACT). This research found that microplastics aged under UV were more prone to wear and tear in the environment, and produced more oxygen-containing functional groups. Chronic exposure experiments were conducted on ACT and aged-MPs. The results revealed that aged-MPs and ACT inhibited earthworm growth, induced oxidative stress, and caused damage to both the body cavity muscles and the intestinal lumen. Compared with individual exposure, combined exposure increased the oxidative products (superoxide dismutase (SOD) and catalase (CAT)) and altered the expression levels of related genes (TCTP and Hsp70) significantly. PE inflicted more significant harm to the earthworm intestinal tissue compared to PBAT. By 1H-NMR metabolomics, the investigation delved into the repercussions of PE and ACT on the metabolic pathways of earthworms. Exposure to ACT and PE can disrupt the stability of intestinal membranes stability, amino acid metabolism, neuronal function, oxidative stress and energy metabolism. Overall, the research revealed that combined exposure of MPs and ACT exacerbated the negative effects on earthworms significantly, and contributed valuable insights to environmental risk assessment of the combined toxicity of microplastics and pesticides.

Estimating the spatial distribution of hydromechanical properties in the investigated subsoil by defining an Engineering Geological Model (EGM) is crucial in urban planning, geotechnical designing and mining activities. The EGM is always affected by (i) the spatial variability of the measured properties of soils and rocks, (ii) the uncertainties related to measurement and spatial estimation, as well as (iii) the propagated uncertainty related to the analytical formulation of the transformation equation. The latter is highly impactful on the overall uncertainty when design/target variables cannot be measured directly (e.g., in the case of piezocone Cone Penetration Test-CPTu measurements). This paper focuses on assessing the Propagated Uncertainty (PU) when defining 3D EGMs of three CPTu-derived design/target variables: the undrained shear resistance (su), the friction angle ((p'), and the hydraulic conductivity (k). We applied the Sequential Gaussian Co-Simulation method (SGCS) to the measured profiles of tip (qc) and shaft resistance (fs), and the pore pressure (u2), measured through CPTus in a portion of Bologna district (Italy). First, we calculated 1000 realizations of the measured variables using SGCS; then, we used the available transformation equations to obtain the same number of realizations of su, (p', and k. The results showed that PU is larger when the transformation equation used to obtain the design/target variable is very complex and dependent on more than one input variable, such as in the case of k. Instead, linear (i.e., for su) or logarithmic (i.e., for (p') transformation functions do not contribute to the overall uncertainty of results considerably.

Erosion and seepage control is a prime concern for embankments, dams, and other hydraulic structures constructed with alluvial sandy soil due to its highly porous characteristics. Permeation grouting has been a popular solution for controlling seepage situations in such structures. In this study, unconfined compression tests and triaxial tests were performed to determine the strength properties of grouted alluvial sandy soil located in the Ganges-Brahmaputra-Meghna delta. A simple method was devised to prepare cylindrical grouted samples with water-cement ratios (W/C) of 2:1, 3:1, 4:1, and 5:1. Here, unconfined compressive strength test results revealed that the highest compressive strength of the grouted sandy soil samples was achieved at the 2:1 W/C ratio at all curing ages. Different failure patterns are observed for different W/C samples during unconfined compressive tests. Furthermore, triaxial tests were conducted on the grouted samples prepared at the 2:1 W/C ratio under consolidated undrained conditions. Dilation occurred during the volume change, and the pore pressure decreased with increasing confining stress. Scanning electron microscopy (SEM) and energy-dispersive spectroscopy were conducted to discern the microstructural behavioral changes and the chemical characteristics of the grouted sandy samples, respectively. Here, SEM images revealed a reduction in porosity with decreasing W/C ratio and increasing curing age. Permeation grouting leads to a reduction in permeability without disturbing the soil microstructure. Therefore, permeation grouting is a very effective technique for improving the mechanical behavior of grouted alluvial sand.

3D printed concrete has emerged as one of the most hotly researched 3D printing technologies due to its advantages of shaping without molds and intelligent construction. Given its low heat of hydration and low carbon emissions slag-based cement is becoming more widely used for 3D printing concrete. However, in the formwork-free shaping process, freshly printed slag-based concrete is immediately exposed to air and loses moisture much earlier than traditional cast-in-formwork concrete. As a result, there is a greater risk of drying shrinkage and cracking and poor volumetric stability of the printed part. This study investigated applicability of photo-polymerization technology in improving the volumetric stability of 3D printed concrete by using UV-curable polyurethane-acrylate (PUA) resin as in-situ sprayed coating on the surface of freshly printed slag-based cement samples. The results show that, in comparison with the uncoated 3D printed cement samples, the volumetric shrinkage of the coated 3D printed cement samples significantly reduced by 44 % after 28 days of environmental curing. For samples of the same age, the compressive strength of the coated test block was increased by 27 % from 20.03 MPa to 25.49 MPa, and the interlayer bond strength was increased by 41 % from 1.46 MPa to 2.06 MPa. The sprayed UV-curable polyurethane-acrylate resin can cure rapidly on the specimen surface within seconds under the irradiation of UV light to form an in-situ protective coating, which is tightly bonded to the surface of the cement, effectively reducing water dissipation and promoting hydration, allowing more even and condense microstructures to form during hydration from the outer surface to the inner part of the printed sample, resulted in a higher strength.

The growth and evolution of sinkholes are a considerable proportion of the damage related to subsidence disaster in alluvial areas after ground water extraction for irrigation. In this research it was tried to study the evolution of the sinkholes from the birth point to the stabilization or final step. In the Eqlid-Abarkooh alluvial fan was selected an area about 300 km2 with giant sinkholes where consist; the city of Abarkooh, arable irrigated lands and desert rangelands. The major aspect on the study area was southwest to northeast where it ended to Abarkooh playa. For investigating the formation and evolution of these sinkholes in the study area, field observation for 2 years were done. Soil samples were taken from surface soils (0-25 cm) near and far of the sinkholes. Moreover, 4 soil samples were obtained from the deepest sinkhole as control sample in the study area. Chemical, physical and mechanical soil analyses were performed. Finally, the Ground Penetrating Radar (GPR) method were done for detection subsurface holes to depth of 4 m around the sinkholes. The chemical soil properties results include Electro Conductivity (EC) and the ratio of Ca2+/Mg2+ in lime which was important factors to formation of sinkholes changed from 2.05 to 19.3 dS/m, 0.15 to 6 respectively. The mechanical soil parameters such as Coefficient of Linear Extensibility (COLE) and Plasticity Index (PI) changed from 0.05 to 1.67, 0.99% to 15% respectively. According to sinkhole development, the results obtained that there was a relationship between diameter of sinkhole obtained from 0.6 to 15 m and groundwater extraction quantity changed from 0.18 to 18.14 m3/ha over 25 years. The groundwater level dropped 15 m and sinkhole volume variation obtained 0.014 to 2650 m3 over 25 years. Field discovery and google earth images showed that sinkholes were developed in 3 phases as (1) growth phase (2) mature and (3) steady phases up to about 25 years. The GPR results found some land breaks and a hole underground in the activation and growth phase of sinkhole evolution. Finally, according to some soil parameters and GPR results, the sinkhole hazard map was created in the study area.

Building structures on clayey soil presents unique challenges to geotechnical engineers due to the inherent variability in clayey soil consistency. Understanding engineering properties of clayey soils is essential for accurate geotechnical design and the prevention of potential issues such as settlement and instability. The current study provides crucial insights for geotechnical assessments and engineering solutions in the area, highlighting key soil properties that affect the classification of clayey consistency. Advanced machine learning (ML) models were employed to predict the in situ clay consistency, a vital parameter for evaluating the deformation resistance of clayey soils under structures. The ML predictions are based on nine features representing the physical and mechanical properties of the clay, which are easily determined through laboratory and field evaluations. A dataset comprising 173 samples is compiled, which extracted from Nile Delta in Egypt, incorporating data on the basic properties of the soils to train and test several ML classification algorithms. The classification models, including logistic regression, k-nearest neighbors, support vector machine, random forest, and gradient boosting classifiers, are evaluated using metrics such as accuracy, sensitivity, specificity, and F1-score. The results demonstrate that the gradient boosting classifier model exhibits the highest accuracy in predicting clay class, achieving 97% and 86% accuracy for the training and testing datasets, respectively. These findings offer a valuable framework for efficiently and cost-effectively classifying clays, assisting geotechnical engineers in making informed decisions about foundation design and construction on clayey soils. Additionally, the study establishes equations to predict the undrained shear strength of clayey soil based on its basic properties, providing a practical and accurate method for estimating soil strength characteristics. These contributions enhance the understanding and management of clayey soil behavior in geotechnical engineering, offering essential guidance for foundation design and construction projects in clayey soil regions.

The raw-material mix ratio and preparation of similar materials are crucial for the success of physical model tests and for accurately reflecting prototype properties. In this study, an optimum similar material for plateau alluvial and lacustrine (PAL) round gravel was developed based on similarity theory. The similar materials were subjected to sensitivity factor analysis and microscopic analysis. Subsequently, the optimum similar material was applied to a three-dimensional (3D) physical model test of an ultradeep foundation pit (FP). The findings show that the similar material prepared with gypsum, LD, bentonite, water, barite powder, and DS at a ratio of 1:1:1.4:3.5:8.8:13.2 was the best for a 3D physical model test of the ultradeep FP in PAL round gravel strata. The sensitivity-factor analysis revealed that barite powder had the greatest impact on gamma, that c and phi were primarily affected by bentonite, and that the LD-gypsum ratio controlled E. A nonuniform particle-size distribution as well as the presence of edge-to-face contacts and small pores between particles constituted the microphysical factors affecting the mechanical properties of the optimum similar material. Using dolomite with a Mohs hardness of 3.5-4 instead of traditional quartz sand with a Mohs hardness of 7 as the raw material can produce a similar material for the target soil with mechanical parameters closer to those of the ideal similar material. The application of the optimum similar material in physical model tests has revealed the stress field response law of ultra deep foundation pit excavation. This study could provide reference and inspiration for the development of similar materials in gravel formations with weaker mechanical properties.

Reconstructing fluvial dynamics is a fundamental requirement for understating the interaction between past environmental changes and human adaptation. This study focuses on the central part of the floodplain of the Nan River in northern Thailand that likely played a role in the catastrophic flood of 1818 CE, which damaged the ancient of Nan city and forced its relocation. We investigated nine sediment cores from the floodplain and from the eastern tributaries of the Nan River, to identify the potential source of floods in the past. By combining the analyses of sedimentary characteristics and provenance, the study reveals that the eastern tributaries were the dominant sediment source for most areas, with the Nan River only influencing areas close to its channel. According to optically stimulated luminescence dating, the highest sediment accumulation occurred during the eleventh to thirteenth centuries CE, coinciding with agricultural expansion and deforestation, suggesting increased erosion in the catchment of the tributaries. These findings challenge the assumption that the main Nan River has been the primary contributor to flooding catastrophes in the region and highlights the potential crucial role of smaller tributaries in similar settings in other parts of the globe.