Deep learning for the static and seismic bearing capacity of shallow strip footings on multi-layered slopes considering spatial soil variability

Progressive failure mechanisms and stability assessment of geotextile bag tailings dams using upper-bound analysis

ABSTRACT With the increase of coal gasification ash production and the environmental problems caused by its accumulation, it is of great significance to study its application in concrete. In this paper, the flexural performance of coal gasification ash concrete beams under low cyclic loading is studied. The effects of coal gasification ash content, concrete strength and reinforcement ratio on the seismic performance of the specimens are discussed. The mechanical properties such as load-deflection, crack width and steel bar strain were measured by experiments. It was found that when the content of coal gasification ash was 20 %, the flexural capacity and seismic performance of the specimen beam were the best. The calculation formulas of cracking load and ultimate bearing capacity based on coal gasification ash were further proposed, and their rationality was verified by ABAQUS finite element simulation. The results show that the proper amount of coal gasification ash can not only improve the mechanical properties of the beam, but also reduce carbon emissions and production costs, which provides a theoretical basis for the promotion of coal gasification ash in engineering applications.

Static performance and failure mechanisms of a rubber-stiffened steel plates with rapid-hardening concrete for sustainable bridge expansion joints retrofitting

Combined bearing capacity of spudcan considering installation effect in clay

Rapid evaluation method for ultimate bearing capacity of circular hollow section gap K-joints with localized corrosion under anti-symmetric axial loading

Local bearing capacity of steel fiber and spirals reinforced UHPC-CA: Mechanism analysis and calculation method

Bias-induced sp³ bonding gradient design for enhancing the frictional bearing capacity of superhard Ta-C coating

Hybrid XGBoost - 3D FEA approach for predicitng bearing capacity of rectangular foundations on rock slopes

Ultimate bearing capacity and multi-scale optimization design of a novel palm-shaped joint in steel structures

Shear properties of UHPC hollow beams with glazed hollow beads

Analytical framework for lateral bearing capacity of two-pile near clay slope: Group and slope effects

Rapid population growth in the town of Mila, in northeastern Algeria, has made urban expansion essential. However, unfavorable soil conditions pose major challenges to urban development. This study aims to characterize subsurface conditions, assess soil mechanical behavior, and establish a geotechnical zoning framework together with an Engineering Ground Model to support safe urban development. An integrated site investigation program was conducted, including 15 Core Drillings, 49 dynamic penetration tests, laboratory analyses, and hydrogeological monitoring. The subsurface stratigraphy consists of clays and marls containing limestone blocks at depths exceeding 20m, together with two slip surfaces identified at depths of - 4m and - 15m. The results of the dynamic penetration tests divide the study area into two zones: one characterized by low peak resistance (Pr = 4.38 MPa) and shallow bedrock (BR = - 1.6m), and the other by moderate conditions (BR = - 6 m and Pr = 18.48MPa). The soils show low chemical aggressiveness (SO42⁻ < 5.5mg/kg), very high clay content (> 75%), high plasticity (21 < Pi < 41.94%), and significant compressibility (Cr = 27.80%, 15.18% < w < 24.54%). X-ray diffraction analysis revealed clay and interstratified minerals dominated by illite (10-30%) and montmorillonite/smectite (≈12.5%). Most of the site is characterized by moderate to low admissible bearing capacity (0.164 < qad(max) < 0.842MPa) for shallow foundations and is susceptible to significant volumetric changes, with settlements exceeding 5cm across large areas. Based on the combined analysis of bearing capacity, settlement potential, groundwater depth, and soil heterogeneity, three geotechnical zones were identified, ranging from highly unfavorable to relatively competent foundation conditions. The spatial distribution of areas with low bearing capacity and high settlement potential closely correlates with the observed patterns of structural damage. The results demonstrate that shallow foundations are largely unsuitable throughout the study area unless ground improvement measures or deep foundation systems are adopted. This study provides a robust Engineering Ground Model and geotechnical zoning framework to guide sustainable urban planning and foundation design in similar clay-dominated, hydro-mechanically sensitive environments.

This study presents the first comprehensive GIS-MCDM site suitability model for a Waste-to-Energy (WTE) facility in Upper Egypt. A sixteen-criterion analytical framework encompassing environmental protection, geological safety, infrastructure accessibility, and social proximity constraints was developed through a structured expert consultation process involving 42 specialists from academic, governmental, and environmental sectors. Criterion weights were derived using the Analytical Hierarchy Process (AHP) and validated with a Consistency Ratio of 2.6% (well below the 10% threshold). Spatial data layers were derived from Landsat-9 imagery (SVM classification), ASTER GDEM (30m), ERA5-Land wind reanalysis, World population grids, OpenStreetMap infrastructure networks, and the Conoco-EGPC geological map of Egypt. Across the 10,698.5km² study area, the integrated suitability map reveals that zones classified as high or very high suitability together constitute only 2.02% of the total area (59.5km²; very high: 0.19%, 6.3km²; high: 1.83%, 53.2km²). The dominant land constraint, 69.3% classified as very low suitability, reflects strict environmental exclusion buffers around protected areas (PA; weight 11.4%), sensitive land uses (SU; 11.2%), surface water bodies (SW; 9.4%), and steep terrain (SP; 9.4%). Three candidate sites with high suitability scores were delineated, with the most favorable located east of Beni Suef city (coordinates: 29°01' N, 31°07' E; area: 22.75km²), proximate to the governorate's largest existing landfill (~ 2.6km) and with favorable north-westerly wind alignment relative to populated zones. This study advances the GIS-MCDM literature by integrating geological (faults, lithology, soil bearing capacity) and environmental safety criteria within an arid-region planning context, an approach insufficiently addressed in prior Egypt-focused or MENA (WTE) siting studies. The resulting suitability model constitutes a reproducible, evidence-based decision-support tool for Egyptian environmental planners and aligns with Egypt's Sustainable Development Strategy 2030 goals for renewable energy diversification and circular economy promotion. The selected site shows potential logistical and economic advantages due to its proximity to existing landfill infrastructure and regional road networks; however, these advantages represent spatial screening indicators and require further techno-economic and network-based transport assessment before implementation. Model validation using ROC-AUC analysis confirmed good discriminatory performance, with an AUC of 0.829, overall accuracy of 90.0%, and Kappa coefficient of 0.801.

Ceramic-matrix composites face a persistent challenge: the trade-off between strength and toughness. Inspired by the mineral bridge architecture of nacre, we propose a reverse interphase design that contrasts with conventional dense-laminar pyrolytic carbon given the active incorporation of nanopores. Multiscale characterization and simulations reveal a dual reinforcement mechanism: nanopores reduce the interfacial debonding strength and induce crack deflection that protects fibers from brittle fracture. Meanwhile, the resulting rough fracture paths enhance interfacial frictional stress and load transfer, thereby improving the matrix bearing capacity and energy dissipation. This asymmetric modulation of interfacial properties simultaneously preserves fiber integrity and maximizes energy dissipation. The resulting single-tow Cf/SiC composites exhibit 903 MPa tensile strength, which is 38% higher than that of conventional designs, and a 1.8-fold increase in fracture energy. The interphase-enabled mechanisms identified here are intrinsically scalable, with their effectiveness further demonstrated in architectured ceramic-matrix composites. This work demonstrates a shift from empirical optimization toward theory-driven interface design and establishes a viable route to overcome the classical strength-toughness dilemma in structural composites.

Under the condition of slicing mining in extra-thick coal seams, the presence of irregular coal pillars is likely to cause stress redistribution in the roadway region and induce rockburst. Taking the "3·22" rockburst event that occurred in the haulage roadway of the 250,101-2 working face in Huating Coal Mine as the engineering background, this paper investigated the occurrence mechanism of roadway rockburst under irregular coal pillar conditions by combining source mechanism inversion, numerical simulation, and theoretical analysis. The results show that the double-couple component is dominant in the moment tensor inversion results, indicating that the source type of this event was shear-type, and that the essence of the rockburst instability was the sudden shear slip of the coal-rock mass under high-stress conditions. The PFC simulation results show that, under the control of an L-shaped irregular coal pillar formed by a 20m residual section pillar and a 34m residual pillar, the overburden load developed a zonal load transfer pattern. Specifically, the 20m pillar constituted the main load transfer channel, while the compacted zone above the 34m pillar regained a certain bearing capacity after compaction of the caved rock mass and exerted an auxiliary reloading effect on the underlying surrounding rock, resulting in the haulage roadway not being in a fully destressed state. On this basis, a two-segment bearing model of the L-shaped irregular coal pillar was established, and the static stress distribution characteristics in the roadway region under the combined action of the two-segment loads were analyzed based on half-plane elasticity theory. Furthermore, by incorporating the attenuation law of vibration waves, a stress increment estimation model under dynamic loading disturbance was established, and the dynamic stress increment generated on the roadway surface by the "3·22" rockburst event was calculated to be about 4.06MPa. Finally, the stress concentration characteristics and stress deflection effect under the control of the L-shaped coal pillar structure were discussed. The results show that an increase in the right-wing thickness of the L-shaped coal pillar structure enlarges the stress deflection zone and enhances stress redistribution toward the roadway, thereby increasing the possibility of rockburst under the combined action of high static stress and dynamic disturbance. The research results reveal the occurrence mechanism of roadway rockburst under L-shaped irregular coal pillar conditions, and can provide a theoretical reference for identifying rockburst hazard zones and optimizing working face layout parameters under similar engineering conditions.

Clay soils in cold regions are highly vulnerable to repeated freeze-thaw cycles (FTCs), yet sustainable and effective stabilization methods that simultaneously enhance mechanical performance, frost durability, and environmental footprint remain underexplored. This study addresses this gap by investigating the synergistic stabilization of frost-susceptible clay using waste marble (WM) powder, nanozeolite (NZ), and polyvinyl alcohol fibers (PVAFs). A comprehensive experimental program evaluated unconfined compressive strength (UCS), indirect tensile strength (ITS), California bearing ratio (CBR), and durability index (DI), of untreated and treated soils (10% WM, up to 2% NZ, and up to 2% PVAF) subjected to up to 10 FTCs, complemented by microstructural analyses using X-ray diffraction (XRD) as well as scanning electron microscopy (SEM) coupled with energy-dispersive X-ray spectroscopy (EDS). In addition, a comparative life cycle assessment (LCA) quantified environmental performance. The optimal mixture (10% WM, 1.5% NZ, 1.5% PVAF) achieved a UCS of 7.8MPa (≈ 37 times that of untreated clay), an ITS of 654kPa, and a soaked CBR of 108%. After 10 FTCs, more than 95% of compressive strength and over 80% of bearing capacity were retained. Multi-scale microstructural analyses confirmed the formation of cementitious hydration products and a cohesive fiber-reinforced matrix. An apparent linear correlation between UCS and CBR supports practical strength estimation. The LCA showed reductions of approximately 59% in global warming potential and over 89% in mineral resource scarcity compared to conventional cement-based stabilization. These findings demonstrate that WM-NZ-PVAF stabilization offers a sustainable, frost-resilient solution for cold-region geotechnical applications, though field validation remains necessary.

To investigate the improvement effect of PVA fibers on the dynamic mechanical properties of concrete in water conservancy dams under dry-wet cycles and impact loads, C40 plain concrete and PVA fiber concrete were selected as the research objects. 0 to 120 dry-wet cycle tests and SHPB dynamic compression tests under different air pressures of 0.2 to 0.5 MPa were carried out. The evolution laws of damage degree, stress-strain curves, peak stress, toughness, energy dissipation and fracture fragmentation morphology of the specimens were systematically analyzed to reveal the strengthening and toughening mechanism of PVA fibers.The results show that the increase in the number of dry-wet cycles and the increase in impact pressure significantly affect the mechanical properties of concrete. The damage degree of both types of concrete increases with the increase in the number of cycles, and the peak stress and toughness continuously decrease.Under the same conditions, the damage degree of PVA fiber concrete is significantly lower than that of plain concrete. Its peak stress, toughness and dissipation energy are all higher than those of plain concrete, and the rate of performance degradation is slower.As the number of dry-wet cycles increases, the internal cracks in the plain concrete rapidly expand and penetrate, showing obvious brittle disintegration characteristics. Meanwhile, the PVA fibers form a three-dimensional network structure in the matrix. Through bridging crack resistance, stress dispersion and energy absorption and toughening effects, they inhibit crack initiation and propagation, delay damage accumulation, and transform the failure mode from brittle fracture to ductile progressive failure.Research has confirmed that PVA fibers can effectively enhance the dry-wet cycle resistance, dynamic bearing capacity and impact toughness of hydraulic concrete, significantly improving its durability and structural safety in complex service environments. This provides experimental basis and theoretical support for the application of high-performance fiber concrete in water conservancy projects.

To address the insufficient bearing capacity of roadside backfill bodies and the tilting or failure induced by uneven pressure relief of the coal seam during gob-side entry retaining in thick coal seams with hard roofs, combined compression-shear loading tests incorporating rapid resistance build-up and varying inclination angles were performed. A novel Compression Shear Coupling Test system (CSCT) was developed, and a fitted relationship between backfill width and roof subsidence was established. The strength degradation behavior of backfill specimens subjected to different shear stress components was systematically investigated. The results reveal that the peak strength of the specimens declines with increasing shear stress component, and the failure mode transitions progressively from compressive to shear-dominated failure. The high-resistance backfill material derived from this study was implemented at the N2302 gob-side entry retaining working face, accompanied by an anti-tilting design for the backfill wall. The measured roof subsidence was reduced by 59.4% relative to the theoretically predicted value, and no evident signs of failure or deterioration were observed in the backfill body. These findings provide both data support and theoretical reference for gob-side entry retaining under similar mining conditions.

Coral sand presents significant challenges to ground improvement design due to its high void ratio, high compressibility, and particle breakage. Traditional bearing capacity theories for vibro-replacement stone columns are typically based on the assumption of soil shear dilation or constant volume. However, these assumptions fail to account for the particle breakage-induced energy dissipation and volume contraction characteristic of coral sand under high stress, leading to significant discrepancies in calculation results. Based on an analysis of the physical and mechanical properties and the breakage mechanism of coral sand, this paper proposes a novel three-step method for in-situ porosity measurement. Furthermore, a dual-mechanism coupling model, incorporating both energy-equivalent additional confining pressure and breakage-friction coupling, is proposed. By introducing the particle breakage energy dissipation coefficient [Formula: see text] and the energy-confining pressure conversion efficiency [Formula: see text], a modified limit equilibrium model for bulging failure is established to dynamically couple the void ratio evolution and the mobilized internal friction angle. Validation through an airport runway project in coral sand geological conditions demonstrates that the proposed method accurately captures the lateral restraint enhancement of coral sand particle breakage. The calculated lateral ultimate stress (166.3kPa) is consistent with the field measured range of 158.0-175.0kPa from nine parallel plate load tests. Considering the full range of measured data, the relative error of the prediction ranges from - 5.3% to + 5.0%. This approach yields significantly higher accuracy compared to traditional standard methods, providing a reliable theoretical basis for engineering design under the conditions of coral sand geology.