Abstract Sustainability and seismic resilience are increasingly essential for infrastructure systems, prompted by the demand to endure more frequent extreme events while minimizing environmental impacts. This paper presents a sustainability-driven, multiobjective framework for assessing and optimizing the seismic resilience of RC bridges on liquefiable ground retrofitted with deep soil mixing (DSM). As such, a nonlinear three-dimensional finite element bridge–ground model is developed to capture the dominant soil–pile interaction mechanisms associated with liquefaction-induced lateral spreading, incorporating various DSM configurations defined by cement content, area replacement ratio, and ground treatment volume. The influence of these DSM parameters on probabilistic seismic demands, fragilities, recovery trajectories, and resilience of the bridge is systematically explored. In addition, the total cost and carbon footprint associated with DSM are estimated based on the established life-cycle assessment data, and three optimization strategies are implemented, including (1) single-objective cost and resilience optimization, (2) multiobjective optimization, and (3) sustainability-driven optimization with simultaneous cost and carbon footprint constraints. The results demonstrate that DSM optimization is essential for balancing seismic performance with economic and environmental considerations. Both budget-driven and sustainability-driven approaches provide cost-effective and environmentally responsible solutions, achieving substantial resilience improvements while remaining within acceptable economic and environmental limits.
Abstract Glauconite sand presence at several offshore wind lease areas in the United States and Belgium has raised geotechnical concerns due to their high crushability and potential for clay-like behavior, introducing uncertainty in pile installation resistance and axial response. Field experience suggests that even relatively low glauconite content can affect glauconite sand behavior, yet no systematic study has isolated this factor as a governing variable. The compression, direct shear, and interface shear response of idealized silica–glauconite sand mixtures containing 0%, 10%, 25%, 50%, 75%, and 100% glauconite particles by weight was investigated under controlled density, moisture, confining stress, and interface roughness conditions. Direct and interface shear tests were conducted primarily under wet (near-saturated, deionized water) conditions at 150 kPa normal stress, with additional direct shear and one-dimensional compression testing at 1,500 kPa normal stress under both wet and dry conditions. Steel interface roughness spanned smooth ground steel to very rough three-dimensional–printed steel surfaces. Particle image velocimetry (PIV) was used to quantify shear-zone development and local strain fields. Results show markedly increased compressibility with glauconite content, especially under wet conditions. Under wet shearing, mixtures progressively transition from dilative, strain-softening behavior (silica-dominated) to contractive, strain-hardening behavior (glauconite-dominated), with multiple indicators supporting a transitional glauconite content between ∼ 25 % and 50% by weight. At higher normal stress under wet conditions, peak and residual direct shear strengths converge across mixtures while contraction increases significantly with glauconite content. Interface friction decreases with increasing glauconite content on smooth steel but increases with roughness for pure glauconite as the mechanism shifts from sliding to soil–soil shearing; PIV measurements confirm associated changes in shear-zone thickness, strain localization, and volumetric response. The findings provide a mechanistic framework for interpreting pile–soil interaction in glauconite deposits while highlighting dependence on the glauconite content, stress level, moisture, and interface condition.
Abstract Pilot-scale injection-based soybean crude urease–based enzyme-induced carbonate precipitation (EICP) (SCU-CP) was evaluated in poorly graded sand using commercially available reagents in a 1 m 3 test box. Solution A (soybean crude urease amended with nonfat milk powder) and Solution B (urea– CaCl 2 ) were pumped separately and combined immediately before injection. The treatment achieved measurable cementation, with unconfined compressive strength reaching up to 497 kPa near injection-influenced zones and up to 355 kPa at the surface layer, while the maximum measured CaCO 3 content reached 2.9%. Postcuring sampling at 64 locations ( 4 × 4 × 4 grid) and three-dimensional mapping showed heterogeneous carbonate precipitation governed by flow pathways and proximity to injection ports. SEM–EDS further confirmed CaCO 3 precipitates on sand grain surfaces and at interparticle contacts, supporting carbonate bonding within the treated matrix. Overall, these results support the feasibility of pilot-scale SCU-CP using industry-relevant materials and highlight that treatment uniformity depends primarily on injection layout, sequencing, and preferential flow control.
Abstract Naturally deposited clays generally exhibit interparticle bonding and fabric anisotropy, which provide additional strength beyond the remolded state and lead to direction-dependent mechanical responses. During loading, microstructural rearrangement, manifested as progressive bond breakage and fabric evolution, enhances energy dissipation and induces irreversible deformation, even when the stress state remains within the yield surface defined by the preconsolidation pressure. This study presents a thermodynamically consistent two-surface model for anisotropic natural clays, in which an enlarged and shifted outer surface represents the bonds-enhanced bounding surface, and an inner surface undergoes a kinematic hardening to capture the plastic deformation occurring within the outer surface. The model incorporates a fabric tensor from the anisotropic critical state theory (ACST) and two isotropic variables related to bonding, with modified evolution laws linked to plastic strain. This framework enables the model to capture the combined effect of bond degradation and fabric evolution on the macroscopic mechanical responses when the stress state lies within the overconsolidated regime. With only nine model parameters, the proposed formulation reproduces experimental results for three natural clays with high fidelity, successfully simulating smooth stress–strain curves, hysteresis loops, orientation-dependent behavior, and strength degradation under monotonic, cyclic, and postcyclic loading.
Abstract This study explores acoustic emission (AE) generation during shearing at coarse particulate–continuum material contacts using a custom-designed micromechanical direct shear apparatus. Through a detailed quantitative micromechanical investigation, it provides new insights into the relationship between AE activity and particle-level contact mechanisms, offering a foundation for advancing AE-based applications. The influence of particle tip geometry, material hardness, surface roughness, normal load, and kinematic freedom on AE and shear responses was systematically evaluated. The results suggest that, under the measurement configuration used in this study, AE was not detected during pure sliding or plowing unless material degradation occurred. Distinct AE bursts are linked to tip breakage, wear, rearrangement, and microtapping, with softer and rougher materials promoting greater AE due to enhanced asperity engagement and contact degradation. Particles with moderate tip angles and constrained motion formed more effective acoustic contacts, resulting in significant shear force drops and AE activity. Additionally, the axis ratio and freedom of particle movement influenced whether sliding, rotation, or rearrangement dominated, thereby altering AE patterns. Rough surfaces amplified AE response by increasing tip wear and interlocking, while smoother interfaces with blunt particles often resulted in acoustic blindness. These findings provide direct evidence of the micromechanical mechanisms responsible for AE in particulate interfaces and highlight the role of tribological interactions in governing shear and AE responses.
Abstract Coextruded geomembranes (GMs) with an ethylene vinyl alcohol (EVOH) layer (coextruded EVOH GMs) are gaining attention as promising barriers in waste containment facilities due to their excellent resistance to organic contaminants. Laboratory-accelerated aging tests were conducted to evaluate the aging of two 1.5-mm-thick coextruded EVOH GMs: Co-BB, with two black surface layers, and Co-BW, with one black and one white surface layer. Both GMs used the same polyethylene resin in their surface layers but had different additive packages. GM samples were immersed in synthetic municipal solid waste (MSW) leachate at temperatures of 22, 40, 65, 75, and 85°C. Comparative tests were conducted on a 1.5-mm-thick high-density polyethylene (HDPE) GM, which used the same polyethylene resin as the coextruded EVOH GMs but contained a different additive package. The results showed that sealed and unsealed Co-BW GM samples exhibited similar aging behavior, indicating that EVOH’s reaction with water has an insignificant effect on aging of coextruded EVOH GMs. Co-BB GM showed the longest standard oxidative induction time (Std-OIT) depletion times, followed by Co-BW GM and then the HDPE GM. For HP-OIT, the coextruded EVOH GMs had longer depletion times at higher temperatures, while the HDPE GM showed the longest depletion times at lower temperatures. Tensile property degradation in the coextruded EVOH GMs is governed by the surface layers, and the faster OIT depletion and earlier degradation of the HDPE GM at 85°C suggests that, with appropriate surface-layer formulations, coextruded EVOH GMs can serve as promising alternatives to traditional HDPE GMs.
Abstract Stone columns are widely used in mitigating liquefaction hazards by accelerating the dissipation of excess pore pressure. However, studies on shaking-induced fine-particle migration and clogging in stone columns remain scarce. In this study, a dynamic centrifuge model test on liquefiable ground with stone columns was conducted to investigate the impact and extent of fine-particle migration and clogging. Employing the transparent soil technique and a back-analysis methodology based on seepage-consolidation theory enabled the observation of clogging and direct estimation of drainage performance in stone columns. The conclusions are presented as follows. (a) Cyclic loading exacerbates fine-particle migration, causing severe clogging and degradation of drainage performance even in stone columns designed by traditional filter design methodologies. (b) The resulting degradation of drainage performance is caused by fine-particle migration and soil densification, with particle migration being the primary factor. (c) This migration and clogging exhibit a clear depth dependency. This study indicates that traditional filter design becomes less effective under cyclic loading, potentially resulting in severe clogging, which should be carefully considered in long-term engineering projects.
Abstract Coral sand, characterized by high compressibility and particle breakage under high-pressure conditions, often contains fines that significantly influence its mechanical behavior. This study investigates the role of fines in the coefficient of earth pressure at rest K 0 and particle breakage in binary coral sand under high-pressure one-dimensional compression. A specially designed high-pressure oedometer equipped with curved earth pressure sensors and friction-reduction techniques was employed. Tests were conducted on binary mixtures with a wide range of fines contents and different coarse-to-fine particle size ratios. Results reveal that both K 0 and particle breakage exhibit nonmonotonic variations with increasing fines content. They first decrease as fines fill voids and improve force chain uniformity and then increase as the soil fabric becomes fine-dominated. Accordingly, an overall increasing trend of K 0 with particle breakage was determined. The final compression states were shown to converge toward a unique curved surface in the void ratio–stress-breakage index space. Relationships between particle breakage and input work under different fines contents were established. Furthermore, particle breakage was found to correlate strongly with the volumetric strain regardless of the influence of fines content, particle size ratio, and vertical stress, following a logistic relationship. The findings of this study provide critical insights into the mechanical behavior of coral sand and have practical implications for the construction of marine infrastructure.
Abstract The effective operation and monitoring of levees constitute pivotal factors in managing and safeguarding lowland territories during flood events and in regular flow conditions. Given their longitudinal structure and spatial soils heterogeneity, the monitoring of levee functionality poses complex challenges. This study investigates the application of a hybrid monitoring system combining traditional sensors and distributed temperature sensing (DTS) to assess seepage in a river levee in the northeast of Italy. The system, installed along three verticals at the levee toe, included pressure transducers and a DTS cable deployed using cone penetration test (CPT) equipment. The DTS system was deployed at the downstream toe of the levee on the landward side to detect temperature variations indicative of anomalous seepage within the levee body, assuming that water filtering through the levee exhibits a distinct temperature signature. To enable this installation method, a special disposable drill tip was developed and here discussed. Monitoring data collected over three years suggest seepage occurred primarily through shallow, permeable layers. This outcome guided the definition of the interventions aimed at mitigating local water seepage, providing insights both pre- and post-construction. Additionally, several finite element method (FEM) analyses of the instrumented levee section were carried out through a parametric study to assess the hydraulic and thermal conditions influencing thermal signal propagation within the levee, rather than to directly reproduce site-specific measurements, for a reliable use of DTS data to detect seepage. The study identified soil permeability as the dominant factor, with thermal properties and hydraulic gradient becoming significant only for low-permeability soils. The monitoring data guided an optimized intervention strategy, limiting sheet pile installation depth and reducing costs. Post-intervention monitoring validated the effectiveness of the intervention. This case study demonstrates the value of integrating advanced sensing technologies with traditional geotechnical practices and numerical modeling to enhance embankment safety assessment and guide targeted, cost-effective interventions.
Ground improvement of liquefiable soils through microbially induced calcite precipitation (MICP) has been shown in previous experiments to be a viable option to increase liquefaction triggering resistance. However, it is unknown how the spatial extent of improvement affects the system performance of an MICP improved soil. In this study, centrifuge experiments were performed on models with treatment depths ranging from 37% to 100% of the liquefiable layer thickness. Additional tests were conducted on untreated (uncemented) and fully cemented baseline models were included for comparison. All models were pluviated with loose Ottawa F-65 sand (DR similar to 40%) and were subjected to eight sinusoidal shaking events. Dense in situ instrumentation arrays tracked accelerations, pore pressure generation, and liquefaction triggering. Bender elements within the cemented zones measured cementation degradation. Through this study, it is shown that partial MICP improvement with depth can generate a base isolation-type mechanism when underlying soil liquefies and thus reduce the intensity of the ground motion in the overlying improved zone. Reductions in ground seismic demand decreases the extent of cementation degradation and prevents liquefaction triggering within the cemented zone. In contrast, MICP cementation improvement of the entire (100%) depth transmits significant shear stress through the soil column, which results in rapid cementation degradation.
The state of practice for assessing soil liquefaction triggering relies on semiempirical models that use the peak ground acceleration (PGA) at the ground surface and the earthquake moment magnitude (M) to represent the seismic demand leading to liquefaction or lack thereof. Analysts have used various methods to compute PGAs at liquefaction case history sites from previous earthquakes. PGA was often taken as equal to the value recorded at the nearest seismic station, sometimes adjusted based on the results of one-dimensional (1D) ground response analyses to account for differences in site effects. Ground motion models or judgment were often used when a site was not located near a seismic station. These approaches do not account for the differences in path effects between the liquefaction site and the nearest ground motion recording, may neglect differences in site conditions between a seismic station and a liquefaction site, and do not generally consider PGA spatial correlation. This paper's objective is to compute PGAs at 569 case history sites in the Next Generation Liquefaction (NGL) database using a consistent approach that builds on previous studies. Three alternative intensity measures (IMs) are also computed at the liquefaction sites, namely peak ground velocity (PGV), Arias intensity (IA), and cumulative absolute velocity (CAV). A comparison of legacy and newly estimated PGAs indicates a mean difference of -0.034 in natural logarithmic units (legacy values larger) and 95% of our values lie between 55 and 180% (i.e., a factor of 1.8) of legacy PGAs. This shows that the previous and new PGA values are comparable as a whole, but individual cases have appreciable differences, the causes of which are explained in this paper.
This paper establishes a soil resistance yield surface for chain links embedded in clay using three-dimensional finite element analysis that considers realistic chain geometries and the effect of embedment depth. The derived yield surface and its associated flow rule are used to develop a new analytical solution for evaluating embedded chain behavior. Unlike existing approaches that decouple axial and normal resistances to embedded chains by assuming a constant friction coefficient, the proposed solution captures the interaction between three-dimensional soil resistance components through the yield surface formulation. The new solution is validated against published experimental data and further compared with existing approaches. A calculation example is presented to demonstrate the evolution of chain configuration, and the results show that the mobilized (or equivalent) friction coefficient-the ratio of the axial to the normal resistance-varies significantly due to the depth-dependent interaction of these two components. By accounting for the coupling of soil resistance components, the proposed solution offers a practical yet readily implementable approach for chain geotechnical design and analysis.
Empirical correlations are extensively employed in geotechnical engineering for their practical simplicity, yet their deterministic nature and neglect of inherent uncertainties often constrain their predictive reliability. This study proposes a joint hierarchical Bayesian model (HBM) that reconstructs three widely used correlations between undrained shear strength (su) and piezocone cone penetration test (CPTU) parameters: (qt-sigma v)/sigma v ', (qt-u2)/sigma v ', and (u2-u0)/sigma v '. By integrating global and site-specific datasets, the HBM improves generalization while maintaining site-level accuracy, particularly in scenarios with limited data. Compared with conventional local and global Bayesian models (LBM and GBM), the HBM demonstrates better model performance and reduced uncertainty. To combine predictions from different empirical models, an adaptive strategy based on the adaptive moment estimation (ADAM) algorithm is proposed to learn optimal model weights. This data-driven method provides adaptive weighting of model outputs as an alternative to traditional Bayesian model averaging (BMA). Validation results show that the ADAM-based approach reduces root-mean-square error (RMSE) by 7%-10%, mean absolute error (MAE) by 6%-10%, and continuous ranked probability score (CRPS) by 2%-5% compared with BMA. Overall, the integration of HBM with adaptive weighting offers a robust and effective framework for enhancing empirical predictions in geotechnical engineering.
A thermodynamic framework is established for water potential in frozen soil. Unfrozen soil pore water and soil pore ice are conceived as intermolecular-scale open thermodynamic systems subject to external fields of gravity, osmosis, and adsorption. Two types of interfaces are considered: an interface between ice and capillary soil water, where the ice-water interface is curved, and an interface between ice and adsorbed soil water, where the ice-water interface is flat. Generality and consistency of the thermodynamic formulation are demonstrated by reduction to the Clapeyron equation, the Gibbs-Thomson equation, the generalized Clapeyron equation, and by direct comparison with premelting theory. The proposed framework predicts the existence of spatially variable pore water pressure in unfrozen water films and provides a mechanistic explanation for an increase in water viscosity within unfrozen water films. Applications to fundamental frozen soil behavior are demonstrated by developing a potential-based framework to predict the magnitude and evolution of unfrozen water film thickness for various soil types and to model the soil freezing characteristic curve.
Energy piles provide an innovative and efficient approach to simultaneously supporting structural loads and developing geothermal energy. During geothermal operations, the thermohydromechanical responses of the soils surrounding energy piles may influence the pile bearing performance by altering the soil-pile interaction. However, knowledge regarding this potential effect remains scarce, severely hindering the accurate assessment of the bearing capacity of energy piles. To address this issue, this study developed a numerical model to evaluate the bearing performance of energy piles under combined mechanical and cyclic thermal loading by considering the thermohydromechanical responses occurring at the soil-pile interface. Then the paper presents the measured results from field static loading tests performed on full-scale energy piles, and uses the established model to realistically capture the pile displacement behavior. Extensive comparison with full-scale experimental data thoroughly validated the effectiveness of the proposed model in capturing soil behavior and pile performance. Subsequently, by utilizing the validated model, the present study investigated the thermally induced variations in the temperature and pore water pressure of the surrounding soils, as well as evaluated their impacts on the load-displacement response of energy piles. Last, the model was used to investigate the behavior of energy piles when exposed to combined mechanical and cyclic thermal loading. The results show that thermally induced changes in the soil-pile contact pressure and thermohydromechanical interactions occurring in the soils collectively govern the evolution of the bearing capacity of energy piles. Heating can enhance pile bearing capacity by increasing the soil-pile contact pressure. However, under certain conditions, the heating-induced increase in pore water pressure may cause adverse effects on the bearing performance of energy piles. Additionally, cyclic thermal loading may induce irreversible thermomechanical responses in energy piles by coupling the mechanical head load. The thermohydromechanical interactions occurring at the soil-pile interface may exacerbate the thermally induced irreversible response of energy piles. Therefore, the thermohydromechanical response within the soils and its impact on soil-pile interaction should be appropriately considered in the analysis of energy pile foundations.
Hydraulic conductivity tests were conducted on geosynthetic clay liners (GCLs) and compacted clays using synthetic municipal solid waste (MSW) leachate containing per- and polyfluoroalkyl substances (PFAS) to determine if PFAS in MSW leachates affect hydraulic conductivity adversely. Tests were also conducted with deionized water (DIW) containing PFAS and with synthetic leachate and DIW alone to distinguish the effects of the leachate and PFAS on hydraulic conductivity. Two sodium bentonite (NaB) GCLs, one bentonite-polymer composite (BPC) GCL, and three compacted clays ranging in plasticity were evaluated to represent a range of clay barrier materials for MSW landfill liners. The synthetic leachate and DIW were spiked with three different PFAS species independently at a concentration of 1,000 ng/L (single-PFAS tests), and with a combination of seven PFAS species (multi-PFAS tests, total PFAS concentration=240,000 ng/L). Permeation was continued up to 3.3 yr. The single-PFAS and multi-PFAS tests yielded hydraulic conductivities comparable to tests with permeant solutions without PFAS (<2-4x and within reproducibility limits). One of the NaB GCLs was up to 6.8 times more permeable to synthetic leachate than to DIW, regardless of whether the permeant solution had PFAS. These findings indicate that PFAS commonly found in MSW leachates are unlikely to significantly alter hydraulic conductivity of GCLs or compacted clay liners used in MSW landfill liners.
Effective stabilization of expansive soils requires chemical reactions, beginning with surface modification (SM) of clay particles, followed by proper pozzolanic reactions (PR). These reactions are achieved by adding appropriate lime content and further enhanced by the incorporation of amorphous silica-rich pozzolanic materials such as rice husk ash (RHA). Before field application, it is essential to evaluate and confirm the occurrence of these reactions and optimize the stabilizer contents to ensure reliable and durable performance. However, this remains a challenge due to the complex mineralogy of natural expansive soils, variability in pozzolanic material chemistry, and limitations of conventional evaluation methods. To address these challenges, the present study proposes a simple laboratory evaluation method using batch test with electrical conductivity (EC) measurement. This method enables determining the optimum lime content (OLC) by identifying the point at which lime becomes available for PR after initial SM. RHA is then incorporated at OLC to enhance pozzolanic activity. Lime consumption and the extent of chemical reactions were confirmed by EC measurement. The study considered four degrees of soil expansivity to represent mineralogical variability. Strength gains were assessed using unconfined compressive strength tests at 7 and 28 days of curing, while durability was evaluated by comparing soaked and unsoaked strengths. This laboratory-based evaluation method offers a technically reliable and versatile approach for optimizing lime stabilization of expansive soils, serving as an effective alternative to conventional measurement techniques for preliminary assessment before field application and mix design. Soil treated using this optimization approach exhibits enhanced stabilization performance and durability. Further, incorporating RHA at the OLC achieves strength gains comparable to those obtained with higher lime dosages. The applicability of lime stabilization supplemented with RHA has been demonstrated across different degrees of expansive soils, ensuring both effective stabilization and durability.
Throughout the service life of pile-supported infrastructures in soft soil, undrained cyclic loading induces excess pore pressure accumulation, causing soil strength degradation. Conversely, subsequent pore pressure dissipation during reconsolidation leads to soil strength recovery. These competing mechanisms continuously alter pile-soil interaction, yet conventional design approaches often overlook the beneficial effects of reconsolidation. This study proposed a novel analysis framework for evaluating pile-soil interaction under cyclic loading and reconsolidation, integrating critical state soil mechanics with the mobilizable strength design method. The framework explicitly captures strength degradation resulting from the accumulation of excess pore pressure and the strength recovery during reconsolidation, making it applicable to the whole-life design of pile foundations. It facilitates the derivation of both monotonic and cyclic p-y curves, enabling robust assessment of pile response using the established p-y method. Furthermore, by integrating a strain power-law relationship, the framework functions as an explicit computational model, enhancing the efficiency of p-y curve determination for specific cyclic loading histories. The validity of the proposed framework is demonstrated through comparisons with results from two centrifuge model tests. Further simulations highlight the framework's capability to capture long-term pile behavior by assessing the effects of degree of reconsolidation, cyclic load amplitude, and loading patterns, showcasing its potential advantages for whole-life design of pile foundations in soft soils.
