DSpace Collection:

GIS-based mapping of bearing capacity and liquefaction hazard for the Srinagar metropolitan region of Kashmir

2026-01-01T00:00:00Z

Title: GIS-based mapping of bearing capacity and liquefaction hazard for the Srinagar metropolitan region of Kashmir Authors: Satyam, Neelima Abstract: This study evaluates the bearing capacity and liquefaction hazards in the sedimentary deposits of the Srinagar Metropolitan Region (SMR) through two novel indices: the Bearing Capacity Hazard Index (BCHI) and the Liquefaction Hazard Index (LHI). The study area is located in the Kashmir Valley, having sedimentary deposits of alluvial floodplains and Karewa highlands, which exhibit significant geotechnical variability due to their distinct depositional environments. BCHI integrates static bearing capacity (SBC), static settlement (SS), seismic-to-static bearing capacity ratio (SBCR), and seismic settlement potential (SSP), while LHI incorporates liquefaction potential index (LPI), liquefaction settlement (S), and liquefaction severity number (LSN). These parameters have then been combined through the Analytical Hierarchy Approach integrated with a GIS platform to develop hazard maps for the region. BCHI has been used to divide the region into zones of bearing capacity hazard: low (< 0.2), medium-high (0.2–0.5), and very high (> 0.5). LHI values have been used to delineate the region based on liquefaction vulnerability: low (< 0.2), medium-high (0.2–0.5), and very high (> 0.5). Results indicate significant spatial variations in geotechnical and liquefaction hazard over the region. The alluvial plains fall in the medium-high hazard zones of liquefaction as well as bearing capacity, whereas the Karewa highlands fall in the low hazard zone of liquefaction and medium hazard zone of bearing capacity. Thereby, the study underscores the severe geotechnical risks in alluvial floodplains, while highlighting Karewa highlands as more suitable for urban expansion. The proposed hazard maps can be used for developing essential guidance for foundation design, land-use planning, and disaster risk mitigation, contributing to safer infrastructure development in the Srinagar Metropolitan Region. © The Author(s), under exclusive license to Springer-Verlag GmbH Germany, part of Springer Nature 2026.

Temporal rheological evolution and early hydration of cement paste under practical temperature and shear conditions

2026-01-01T00:00:00Z

Title: Temporal rheological evolution and early hydration of cement paste under practical temperature and shear conditions Authors: Sharma, Astha; Singh, Krishna; Sharma, Gaurav; Chaudhary, Sandeep Abstract: Early-age rheology of cement paste evolves continuously with time due to hydration, directly affecting handling and placement; however, the combined roles of crucial influential parameters are not yet fully understood under practical conditions. This study investigates the effect of temperature, shear rate, and w/c on the temporal rheological behavior of cement paste. Rheological tests were conducted at 15 °C, 25 °C, 35 °C, and 45 °C for pastes using different w/c under controlled shear. To relate stress evolution to hydration, paste samples were hydration-arrested at 15, 30, and 60 min and analyzed using XRD and SEM. Results show that higher temperatures accelerate hydrate formation and stress development, but the resulting hydrate networks are unstable under sustained shear. At lower temperatures, structural development remains limited despite lower w/c. The findings show that early-age rheology is influenced by hydration progress and stability of hydrate networks, supporting practical rheological windows for conventional and advanced construction processes. © 2026 Informa UK Limited, trading as Taylor & Francis Group.

Nonlinear bending of laminated composite rhombic stiffened elliptical paraboloids

2026-01-01T00:00:00Z

Title: Nonlinear bending of laminated composite rhombic stiffened elliptical paraboloids Authors: Singh, Natvar; Bakshi, K. Abstract: This study investigates bending performance of laminated composite rhombic stiffened elliptical paraboloids which is missing in the literature. The deflections, force, and moment resultants of uniformly loaded panels are solved using a C0 continuous finite element code that combines geometrically nonlinear strains, first-order shear deformation theory, and eight-noded elements. The governing equation is derived by minimizing the total potential energy and solved through the Newton-Raphson iterative approach. Experimental and closed-form results are used as the benchmarks to confirm correctness of the proposed model. The bending performance of panels with central and multiple stiffeners is studied for different boundary conditions, laminations of graphite and glass-epoxy composites, and side tilts of rhombic panels. The number, thickness, and locations of stiffeners are varied. Effects of varying shear correction factors are studied also. The bending actions are minimized when 0°/90°/0°/90° laminate and 7 × 7 stiffeners are adopted for CFCF panels. The 0°/90°/0° laminate and 7 × 0 stiffeners should be preferred for FCFC panels. The panels tilted to 30° perform the best, especially for eccentrically concave stiffeners having a depth 10 times that of the panel thickness. © 2026 Taylor & Francis Group, LLC.

Shear strength and durability enhancement of fly ash and bottom ash mixed soil using microbial-induced calcite precipitation: A comparative study

2026-01-01T00:00:00Z

Title: Shear strength and durability enhancement of fly ash and bottom ash mixed soil using microbial-induced calcite precipitation: A comparative study Authors: Rawat, Vikas; Satyam, Neelima D. Abstract: Coal ash, a byproduct of coal combustion, is produced in large volumes globally, posing environmental risks due to landfill disposal. Reusing or stabilizing coal ash is essential for mitigating these risks. Fly ash (FA) and bottom ash (BA) exhibit pozzolanic properties that improve soil properties, making them suitable for geotechnical applications, especially as backfill materials. However, slow curing and insufficient strength limit their use. To overcome these limitations, this study explores microbial-induced calcite precipitation (MICP), a sustainable and eco-friendly ground improvement technique, to enhance the strength and durability of FA and BA-mixed soils. Biotreatment was performed using Sporosarcina pasteurii and a cementation solution, applied at one pore volume per cycle over a 9-d period. The effects of FA and BA on biocementation were evaluated at varying concentrations relative to soil weight. Unconsolidated undrained (UU) triaxial tests were conducted to assess shear strength parameters. Calcite content and microstructural analyses, including scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS), were used to evaluate biocementation. The results showed that FA and BA improved soil strength, with optimal performance at 3 % ash content. Excessive FA and BA reduced bacterial mobility, limiting calcite precipitation. Durability tests under wetting-drying (WD) and freeze-thaw (FT) cycles revealed that FA-mixed samples exhibited better resistance to degradation than BA-mixed samples, with lower mass loss and minimal strength reductions. Overall, both FA and BA-mixed samples exhibited significant strength and durability, making them suitable for high-performance backfill materials. However, FA-mixed samples outperformed BA-mixed samples, offering superior strength and durability. © 2026 Institute of Rock and Soil Mechanics, Chinese Academy of Sciences