Resumen en Inglés:

Abstract Human activity brings several risks of contamination with pollutants of varying types and effects, with hydrocarbon compounds being of great concern as they are released by vehicles, industrial and construction activities and in areas with fuel reservoirs, among others. Hence, when these contaminants reach the soil, a legitimate question arises regarding their impact on the soil's resistance characteristics. This work presents a case study of granite residual soils contaminated with gasoline under 8-, 16-, and 32-days, within index properties and geomechanical tests were analyzed to support remediation decision. CBR tests showed inconsistent results at shallow depths but a 16% capacity reduction beyond 12 mm with green gasoline. Direct shear tests showed similar friction angles but increased cohesion from particle aggregation, raising rupture stress by up to 68%. Oedometer tests showed greater deformability and lower yield stress, with compressibility coefficient around 0.133-0.161, in contaminated soils, aligning with large-deformation CBR trends. It seems that gasoline is a complex addition to the soil-water-air interaction, possibly transforming the soil into a hydro-phobic material and thus separating the water as the connecting agent, affecting the overall structure and support capacity of the soil. Future studies should focus on hydrocarbon percolation and leaching behavior in field conditions.

Resumen en Inglés:

Abstract Compacted soils are a common component of engineering structures worldwide. In tropical regions, lateritic soils exhibit distinct characteristics due to soil aggregation from iron and aluminum hydroxides and their bimodal structure. However, the compaction process can alter soil structure and mechanical behavior. This paper aims to assess the effects of soil structure on the saturated and unsaturated mechanical behavior of a lateritic soil under different compacted energies. The methodology involves porosimetry, retention curve and saturated and unsaturated triaxial tests, using appropriate standards and references. Under saturated conditions, these structural variations affected the volumetric behavior at the critical state, particularly in samples compacted on the dry side of the compaction curve. Additionally, a unique Critical State Line (CSL) could be traced for all samples in the p’ x q space. Under unsaturated conditions, the effects of soil structure were evident, with both the volumetric response and shear strength increase being influenced by suction. Samples molded with no compaction energy, or non-proctor energy, resulted in higher macropore void ratio leading to more pronounced volumetric contraction during shear and less gain in shear strength. Therefore, this work contributes to the understanding of the behavior of compacted laterite soils, providing valuable information for projects involving compacted laterite soils in the field, such as dams, embankments and pavement subgrade.

Resumen en Inglés:

Abstract The urban subsurface represents a critical underutilized resource for addressing the rising energy and infrastructure demands of modern cities. Among the emerging technologies that use this potential, energy geostructures offer an innovative, sustainable, and cost-effective solution. By integrating geotechnical engineering principles with energy functionality, these systems provide both structural stability and renewable heating and cooling energy for buildings and infrastructure. Over the past three decades, extensive research has advanced the understanding of the behavior of different types of energy geostructures, including energy piles, barrettes, walls, and slabs, and analytical and numerical tools have been developed to support their design and optimization. This study synthesizes a number of these advancements, focusing specifically on building foundations, and emphasizes the transition from theoretical research to practical implementation. Through discussion of key design methodologies and real-world case studies, it highlights the critical role of energy geostructures in reducing fossil fuel dependence, enhancing energy efficiency, and contributing to the decarbonization of the built environment.

Resumen en Inglés:

Abstract Expansive soils cause considerable challenges in road construction due to their volumetric changes, which can lead to pavement deterioration. Although conventional soil stabilizers are effective, they are too expensive and not environmentally friendly. This study examines the use of locally available teff and enset natural fibers, which are derived from the enset and teff plants, as sustainable alternatives for reinforcing expansive soil obtained from Wolaita, Ethiopia. The variations of the teff and enset fibers used in this study are 0.25; 0.5; 0.75 & 1%. The untreated soil displayed a Maximum Dry Density (MDD) of 1.429 gm/cm3, Optimum Moisture Content (OMC) of 25.71%, California Bearing Ratio (CBR) of 2.85%, and an Unconfined Compressive Strength (UCS) of 36.5 kilopascals. The incorporation of these fibers led to significant enhancements in these properties, with an increase of 4.4% in dry density, 163.2% in CBR, and 352% in compressive strength. Moreover, notable reductions in moisture content, plasticity index (PI), free swelling, and linear shrinkage were recorded, resulting in maximum decrease of 22.6%, 8.6%, 78.3%, and 81.2%, respectively. Optimal performance was achieved by adding 0.75% of each fiber type to the soil, cut to a length of 20 mm, which was compacted at its MDD and OMC. These findings suggest that such locally available natural fiber reinforcement can be a cost-effective and environment friendly solution for improving the engineering properties of expansive soils that can be judiciously utilized in road construction. Statistical models were developed to predict the CBR value based on other index properties of the soil showing close agreement with experimental findings.

Resumen en Inglés:

Abstract The growing number of researchers dedicated to finding efficient solutions for the disposal or reuse of tailings material is explained due to mining intrinsic environmental issues such as large areas needed for tailings disposal and the severe destructive impact of recent mining dam failures. This paper summarizes comprehensive research on geotechnical parameters of compacted iron tailings ore in the southeast of Brazil, with focus on how to define the ideal tailings mixture for building static barriers against the impact of an eventual tailings dam failure. The study was based on field and laboratory results from experimental earth fills, built with compacted tailings mixtures under various combinations of conditions and equipment. It was also based on the need to understand the behavior of tailings under compaction in order to ensure the proper use of its parameters. The main purpose of this paper is to suggest the best tailing mixture to improve future design based on field tests results.

Resumen en Inglés:

Abstract Managing groundwater seepage around tunnels is critical to tunnel design, particularly when the tunnel is constructed below the water table. Accurate seepage flow patterns and water inflow prediction under ordinary and critical conditions are imperative to mitigate potential tunnel construction and service disasters. In the past, an in-depth study on the anisotropic hydraulic conductivity of the soil mass that may affect the seepage condition has not been carried out. In this work, this aspect has been investigated numerically for a rectangular tunnel submerged within a homogeneous sand mass, considering the anisotropic hydraulic conductivity ratio (kz/kx, kz = vertical hydraulic conductivity and kx = horizontal hydraulic conductivity) varying from 0.25 to 1. This study has presented the changes in the flow patterns of groundwater around a rectangular tunnel for different values of kz/kx, and the variation of water inflow rates along the crown, invert and walls of the tunnel. The results indicate that as kz/kx decreases from 1 to 0.25, the water inflow rate into the tunnel reduces linearly and the invert of the tunnel experiences the highest inflow rate. The total water inflow into the tunnel when kz/kx= 1 is three times the inflow rate for kz/kx= 0.25. An illustrative example has been included to help tunnel designers and construction engineers utilize the findings of this study for practical lining and permanent tunnel drainage systems.

Resumen en Inglés:

Abstract Lateritic soils are widely distributed in tropical regions and are characterized by a cemented structure due to iron and aluminum oxides. Although the Standard Penetration Test (SPT) is commonly used in Brazil, it does not adequately capture the stiffness of these cemented layers, leading to overly conservative pile design and increased costs. To address this limitation, this study presents a reevaluation based on 43 pile load tests in lateritic soils across various Brazilian sites. Results confirm that the traditional method by Décourt & Quaresma (1978), as later adapted by Décourt (1996), underestimates shaft resistance, with measured values averaging 2.1 times higher. This study proposes an adjustment methodology introducing a correction factor for lateritic soils (β = 2), which produced satisfactory predictions in 76.75% of cases, with 39.5% within a ± 20% margin. However, 23.25% of cases exceeded this range, mainly for manually excavated small-diameter piles, indicating sensitivity to construction methods and the need for site-specific calibration.

Resumen en Inglés:

Abstract The natural variability of soil, influenced by weathering, human activity, and geological formation processes, is a critical factor in geotechnical engineering. This variability introduces significant uncertainty, particularly in the design of deep foundations, where the complex interaction between soil and structures, combined with varying geological conditions, complicates the prediction of structural behavior. However, focusing on deep foundations, this study examines soil property variability in southern Brazil. Standard penetration tests and slow static load tests were conducted to estimate pile load-bearing capacities. A reliability assessment method was employed to evaluate the accuracy of different prediction techniques, with results compared against load-settlement test data. Findings reveal significant discrepancies between prediction methods, with longer piles satisfying safety requirements, while shorter piles showed higher variability and did not meet the same safety standards. This research highlights the importance of incorporating soil variability and probabilistic analysis into foundation design to enhance reliability and safety.

Resumen en Inglés:

Abstract This study aims to estimate the settlement of two distinct angular footings (i.e. distinct square-square, rectangular-rectangular and square-rectangular footings) found alongside on homogeneous, isotropic and elastic granular medium. The settlement of these footings has been assessed by considering the interference effect as the footings are in closed proximity. To evaluate the interference settlement for two distinct angular footings found alongside on the surface of the granular medium, a simplified method has been proposed based on the principle of superposition. The assessment is carried out by varying length-to-width ratio, clear spacing between the footings, loads on the footings, centre lines, and footing width. The outcomes are provided as interference factors. The study shows that, the settlement interference factors were more pronounced for the smaller footing, even with symmetrical loads. These factors increased as the load intensity on the adjacent footing grew and were higher with smaller spacing and reduced with greater spacing between the footings. The impact of interfering settlements owing to embedment depth is also investigated and reported as a settlement ratio. The findings were compared to the available literature.

Resumen en Inglés:

Abstract The determination of soil shear strength parameters is essential in geotechnical projects and traditionally relies on laboratory tests, which can be expensive, time-consuming, and, in some cases, unfeasible. As a preliminary alternative, correlations based on in-situ tests can be used, however, such correlations are generally limited to sands or clays, restricting their applicability in many practical situations. A potentially more comprehensive solution is the development of models capable of relating the Standard Penetration Test (SPT), the most widely used field test in geotechnical practice, to the Mohr-Coulomb strength parameters, cohesion (c’) and friction angle (ϕ’), while accounting for different grain-size fractions. This task is challenging due to the high variability of the variables involved, however, by using machine learning techniques, such as artificial neural networks, which are capable of handling complex and nonlinear relationships, it has been possible to overcome part of these limitations. The proposed model also incorporates a relevant contribution: the numerical treatment of the “soil type” variable, allowing the network to account for differences among sandy, silty, and clayey soils. With a representative dataset, the model achieved correlation coefficients of 0.85 (training) and 0.90 (testing), with mean errors of 5.3 kPa for c’ when c’ < 20 kPa, and 2.36° for ϕ’ in the range 25° ≤ ϕ' < 35°. In addition to demonstrating superior performance compared to models available in the literature, the model is capable of handling different grain-size fractions. It is concluded that the model shows satisfactory performance for preliminary applications in geotechnical engineering practice, allowing estimates of the strength parameters within well-defined validity ranges, however, it does not replace the need for laboratory testing.

Resumen en Inglés:

Abstract This study presents the results of measurements performed during SPTs conducted with a mechanized system as part of the soil investigation for Paranaguá harbor, in Paraná state, Brazil. The energy delivered to the rod stem was measured in ninety-two blows. Additionally, the hammer and rod displacements were independently measured in thirty-one of these blows, which allowed the quantification of all energy losses, from the hammer release to the rod stem just below the anvil. The results showed that, for the particular equipment used, secondary impacts within the same blow have less influence on the energy transferred to the rod stem. This resulted in the energy ratio varying with depth, unlike in significant previous experience, where it was found to be constant.

Resumen en Inglés:

Abstract This study presents the application of a piezoball penetrometer equipped with pore pressure transducers at the tip, mid-face, and equator positions to characterize the undrained shear strength and consolidation behavior of a soft clay deposit in southern Brazil. Two piezoball tests were performed with cyclic and dissipation measurements, alongside piezocone, field vane, and laboratory tests. Undrained strength estimates based on penetration resistance aligned well with piezocone and vane test results, using an average bearing factor aligned with international practice. Remolded strength revealed sensitivity to the time interval between penetration and extraction readings, with longer delays leading to overestimation. Dissipation tests showed contractive pore pressure behavior, and consolidation coefficients derived from normalized curves at the equator sensor position were closest to piezocone-based values. The study provides practical recommendations for piezoball testing and highlights the importance of time control during cyclic measurements, reinforcing the importance of expanding robust geotechnical databases to support future applications.

Resumen en Inglés:

Abstract The performance of soils and granular materials must be considered in relation to the main deterioration mechanisms in pavement structure design. This study aims to evaluate the use of fine-grained soils as unbound materials in pavement applications. For this purpose, physical, chemical, and mechanical characterization tests were conducted. Repeated load triaxial tests were performed following current Brazilian standards and considering different soil saturation conditions. Five widely used mathematical models were employed to assess the resilient modulus under different moisture conditions, with the Compound and Universal models showing the best correlations. As moisture content increased, a reduction in resilient modulus was observed at higher stress levels. Regarding permanent deformation, the master curve approach was applied to obtain the parameters adopted as inputs for simulations within the mechanistic-empirical pavement design software, FlexPaveBR version 2.1.5. The model results adequately represented the plastic behavior of the analyzed conditions. The simulation results indicated differences between considering bonded and unbonded granular layers. The results also indicated that the use of fine-grained soils without stabilization can be considered for subbase layers, provided that triaxial testing is conducted and the materials demonstrate satisfactory performance under mechanistic-empirical evaluation.

Resumen en Inglés:

Abstract Deep-water regions, such as the Brazilian Pre-salt, are characterized by decreasing temperatures with increasing depth, which causes changes in the rheological parameters of marine soils, which is essential in the context of submarine debris flows. To investigate these effects, rheological characterization was performed through tests conducted at 6°C, 13°C, and 20°C, using a concentric cylinder rheometer programmed to apply a shear rate ranging from 0 to 100 s-1. The flow curves obtained were analyzed using the Bilinear rheological model, which describes the behavior of the soil before and after the yield stress, defined as Regimes I and II, respectively. As the temperature decreased, the results revealed a significant increase in yield stress, indicating that marine soils exhibit greater shear strength at lower temperatures. Additionally, correlation curves were plotted for the yield stress as a function of the liquidity index using the model proposed by Hotta et al. (2024) for different temperatures and three different correlation equations were obtained, one for each temperature. The analysis showed that the yield stress decreased exponentially with increasing liquidity index and that higher water content reduced the influence of temperature on the rheological behavior of the soil. Based on these findings, a rheological model was developed that incorporates variations in the liquidity index and temperature, enabling a more accurate prediction of yield stress as a function of these two variables These findings are highly valuable for understanding the behavior of soils during submarine debris flows, as the material behaves like a fluid and its movement is governed by rheological properties.

Resumen en Inglés:

Abstract Expansive soils are prone to strength degradation after rainfall, yet conventional slope stability analyses often rely on laboratory-derived shear strength parameters that may overestimate in-situ conditions. This study evaluates and compares the shear strength of expansive soils using the borehole shear test (BST), laboratory direct shear test (DST), and consolidated undrained test (CUT) under natural and flooding conditions. Results show that shear stress- shear displacement (or axial strain) curves generally exhibit weak hardening characteristics. Significant reductions in cohesive strength occur after flooding. The cohesive force obtained by DST and BST decreases by 18.2 kPa and 13.1 kPa after flooding respectively, while the internal friction angle decreases slightly within 3°. Laboratory tests consistently yield higher strength parameters than BST, while flooding BST values closely align with those measured on actual slip surfaces. Numerical modeling of an unstable cut slope confirms that using flooding BST parameters produces more realistic safety factors. The findings highlight the importance of incorporating in-situ testing under representative moisture conditions for reliable slope stability design in expansive soils.

Resumen en Inglés:

Abstract Achieving sustainable infrastructure requires the efficient valorization of regional biomass, such as açaí (Euterpe oleracea) residues. This study provides a multi-scale characterization of untreated and colloidal silica-treated açaí fibers, focusing on their application as sustainable geotechnical reinforcement. The fibers exhibit an average diameter of 0.136 mm and a naturally rough surface densely populated by silica microgranules, favoring mechanical interlocking. Chemical and lignocellulosic analyses (FTIR, XRF, and acid hydrolysis) revealed a high lignin content (45%) and moderate cellulose crystallinity (49%), indicating intrinsic robustness. However, untreated fibers showed high moisture susceptibility, with 80% absorption. The colloidal silica treatment created a stable, silicon-rich protective layer, reducing water absorption by 50% and neutralizing surface acidity, as evidenced by XRF and ash content increase to 17%. Thermogravimetric analysis by TGA/DTG demonstrated enhanced thermal stability and higher char yield for treated fibers, while tensile testing revealed a favorable balance between strength (≈250 MPa) and ductility (7.8% elongation). By bridging the gap between fiber micro-geometry and geotechnical requirements, these results demonstrate that treated açaí residue is a durable, high-value geomaterial for sustainable soil reinforcement in tropical environments.

Resumen en Inglés:

Abstract Calcium phosphate biocement with soybean as a urease alternative can be used for sand soil stabilization. Bone meal (BM) solution serves as a source of calcium and phosphate, whereas soybean acts as a urease catalyst that supports the precipitation of calcium phosphate (Ca3(PO4)2). This study aims to determine the optimal composition of a calcium phosphate biocement solution for sand soil improvement by evaluating direct shear strength parameters. The concentrations of soybean and BM increased the precipitation mineral mass by up to 0.67 g at a BM concentration of 0.4 mol/L and 50 g/L soybean, which became the optimal composition. In the direct shear test, the cohesion value increased from 0 to 16.13 kPa after 28 d of curing. However, there was a slight decrease in the internal friction angle from 27.18° under untreated soil conditions to 18.49° after 28 d of curing. In addition, the shear stress increased to a maximum of 34.16 kPa at a normal stress of 5.21 kPa after 28 d of curing. The mineral compositions formed were hydroxyapatite, calcite, and brushite. Hydroxyapatite is a calcium phosphate crystal group that dominates sand soil samples with hexagonal, needle-like, and amorphous phases.

Resumen en Inglés:

Abstract Microbially induced calcite precipitation (MICP) is a sustainable technology which utilizes biochemical processes, to produce calcium carbonate (CaCO3) in the presence of Urea, calcium chloride (CaCl2), and microorganisms. The application of the MICP process, via biostimulation of natural microorganisms, to a natural sandy soil that was contaminated in the laboratory with hexavalent chromium (Cr6+) and cadmium (Cd2+) was investigated. The improvement of the soil’s geomechanical strength and the increase in its capacity to immobilize both contaminants were evaluated. An experimental program was carried out with bioreactors to evaluate the influence of three main parameters: Cr6+ (X1), Cd2+ (X2) and the volume of biocementation solution (X3). The experiment was carried out in the laboratory, with bioreactors, with 5cm of contaminated soil, 25 cm of uncontaminated soil and 10 cm for insertion of the biocementation solution. Monitoring of urease behavior indicated that initial concentrations of 20 mg.kg−1 and 40 mg.kg−1 for Cr6+ and Cd2+, respectively, were not toxic to urea hydrolysis. Movement of contaminants occurred during the leaching of the biocementation solution, however, contaminant immobilization showed maximum values of 95.67% for Cd2+ and 87% for Cr6+. The uniaxial compressive strength (UCS) test reached values between 114.84 and 917.43 kPa. This indicates that CaCO3 precipitation occurs even in a toxic environment, immobilizing and promoting the biomineralization of contaminants. In conclusion, MICP could be a promising sustainable technique for application in contaminated soil.

Resumen en Inglés:

Abstract This study evaluates various methods for estimating soil water retention curves (SWRCs) in tropical residual soils from the Baixada Santista region, Brazil, including both young and mature profiles. Laboratory data were obtained using HYPROP, WP4C, and the filter paper method, and curve fitting was performed using unimodal and bimodal van Genuchten models. The estimates were derived from mercury intrusion porosimetry (MIP), pedotransfer functions (PTF-SV and PTF-Bi), and inverse modeling with Hydrus-1D, using field moisture and rainfall data from CEMADEN. Model performance was assessed using RMSE, MAE, MBE, and correlation coefficients. For mature soils, PTF-SV showed the best statistical performance but failed to represent bimodal structure. In contrast, PTF-Bi and MIP better reflected dual porosity but with higher errors. For young soils, Hydrus-1D produced the best fit, especially in simpler pore systems. Although the models showed a strong correlation with laboratory data, they often yielded divergent van Genuchten parameters, indicating that statistical agreement does not necessarily ensure an accurate physical representation. No method consistently outperformed others across all soil types. These findings highlight the influence of soil structure and calibration data on model reliability and reinforce the need to develop tailored approaches for Brazilian tropical soils with complex hydraulic behavior.

Resumen en Inglés:

Abstract The phenomenon of soil swelling is primarily caused by climatic conditions such as drought and rain, as well as the mineralogical composition of soils. These factors strongly influence the shrinkage–swelling behavior of clays, which can cause significant damage to structures. Several techniques exist for the design and stabilization of expansive soils. This study presents a chemical stabilization approach by adding low percentages (2–8%) of lime and cement to a swelling clay from southern Algeria (Laghouat clay). Initially, materials were characterized using standard geotechnical tests, supplemented by chemical and mineralogical analyses. Based on identification tests, an indirect method to estimate the soil’s swelling potential was developed and validated by direct measurements of swelling parameters. Subsequently, various mixes were tested to evaluate the effect on shear strength. The results indicate a significant reduction in swelling potential, free swelling, and plasticity index (approximately 80%, 90%, and 90%, respectively), along with a marked increase in cohesion from 111 kPa to 313 kPa (about threefold). These findings confirm that low percentages of lime and cement are effective for stabilizing expansive soils while improving their mechanical properties.

Resumen en Inglés:

Abstract This study evaluates the use of Class F fly ash (FA) and ground granulated blast furnace slag (GGBS), traditionally considered a waste material, as a replacement and partially reactive material in geopolymer stabilization of lean clay (CL) soil for sustainable pavement applications. The effects of NaOH concentration (4M, 8M, 12M, and 16M), GGBS content (0%, 5%, 10%, and 15%), and curing duration (7, 28, and 60 days) on mechanical and durability properties were analyzed. Results showed that the 10% GGBS blend achieved the highest UCS of 13.62 MPa at 12M NaOH after 60 days, meeting Indian Roads Congress standards. Sulphate resistance tests revealed minimal UCS loss (2.83% at 4M) for the 10% GGBS mix, compared to 34.62% for blends without GGBS. Strength transitioned from ductile failure at 7 days to brittle failure at 60 days, indicating matrix development. A strong linear correlation (R2 = 0.98) between UCS and stiffness (G) enables practical predictions. This research highlights the viability of FA-GGBS geopolymer blends as a sustainable alternative for soil stabilization in pavement applications, promoting resource utilization and waste reduction.

Resumen en Inglés:

Abstract Significant fatalities, infrastructure destruction, resource depletion, and land degradation are all consequences of landslides. Growth and adequate mitigating efforts are sometimes blamed for their increasing prevalence. Conventional control methods also contribute to environmental imbalance due to their massive carbon footprint. Soil erosion from slopes and plant loss caused by human activity increase the frequency of landslides. Vetiver grass (Chrysopogon zizanioides) and other sustainable and environmentally acceptable techniques are therefore essential for erosion management. For this study, eight 45° small-scale slope models were constructed, four of which were bare (later planted with vetiver) and four of which were reinforced with jute geotextile and vetiver roots. In order to assess runoff control and erosion, four types of soil - red, black cotton, laterite, and sandy soils were utilized in the models. Following 90 and 365 days of planting, high, moderate, and low intensities of artificial rainfall were applied. The results showed that vegetation reduced cumulative runoff by 21 - 26% and increased infiltration by 25 - 45% for black cotton, red, and laterite soils. Silty sand performed even better, with 60% greater infiltration and 30% less runoff. Additionally, compared to other soils, the amount of soil eroded in sandy soil is reduced to 0.018 kg. The protection of canopy and root reinforcement significantly reduced runoff and erosion. In the early days, erosion was discovered to be successfully reduced by the combination of vetiver and jute geotextile. Vetiver generally performed better in soils with more sand, indicating that soil type had a major influence on erosion processes. All four soils reached stable cumulative erosion after runoff and erodibility increased linearly with rainfall intensity above a particular threshold.

Resumen en Inglés:

Abstract This paper presents the design and development of a comprehensive standalone application for geotechnical engineering, built entirely using Python. Unlike conventional commercial platforms or numerical packages, the application focuses on providing transparent, reproducible, and analytically grounded tools for core geotechnical challenges. This article aims to present the topic in a straightforward and easy-to-understand manner. The application includes different independent modules that cover critical areas of soil and rock mechanics, foundation engineering, tunnel lining design, slope stability, and ground improvement. All modules are based on classical solutions, derived from principles such as Rankine’s and Coulomb’s earth pressure theories, Terzaghi’s bearing capacity equations, consolidation and elastic settlement theory, the Hoek–Brown rock failure criterion, etc. The software leverages Python’s scientific libraries for data operations, interpolation, plotting, regression, and features a graphical user interface (GUI) built by Tkinter for interactive input and visualization. By adopting a modular architecture, each analytical solution can be accessed, maintained, and extended independently, promoting both scalability and usability. The program has been validated against standard geotechnical design examples and empirical relationships, showing excellent agreement. It serves both educational and professional purposes.

Resumen en Inglés:

Abstract Quantifying the main sources of uncertainty associated with analytical models for predicting reinforcement loads is essential for ensuring safety, supporting reliability analyses, and enabling reliability-based optimization in geotechnical design. This paper presents a probabilistic framework to characterise uncertainty in load prediction models for geosynthetic-reinforced soil walls. Model uncertainty is assessed through a Bayesian updating framework that compares analytical predictions with monitoring data from well-instrumented walls, while explicitly accounting for the uncertainties associated with model parameter estimation. The random variables considered include the soil unit weight and the angle of internal friction. The applicability of the framework is illustrated using two simple analytical methods: the American Association of State Highway and Transportation Officials (AASHTO) Simplified Method and the K-Stiffness Method. This framework also allows model uncertainty to be updated as new monitoring data become available. In addition, it can be extended to other analytical or numerical models commonly employed for the design of geosynthetic-reinforced soil walls. This flexibility enhances its potential for practical adoption and for guiding future reliability-based studies.

Resumen en Inglés:

Abstract This paper took a typical high-slope project of a mountainous highway in Deyang City, China, as the research subject, and conducted a sensitivity analysis of anti-slide pile support parameters based on finite element numerical simulation. This slope is located on the eastern edge of the Longmenshan Fault Zone, with large topographic fluctuations and strongly weathered rock and soil masses. There have been multiple shallow landslides in history, posing a potential threat to road traffic safety. To scientifically evaluate the effectiveness of the support scheme, the research first constructed a finite element model based on the on-site engineering geological survey data. The model used the Mohr-Coulomb elastoplastic constitutive relationship to describe the soil behavior. The anti-slide pile structure was simulated by linear elastic beam elements, and the nonlinear interaction between the pile and the soil was accurately characterized through the contact interface elements. Before the formal parameter analysis, the effectiveness of the constructed finite element model was verified. Then, the slope stability was tested when the cross-sectional diameter of the piles was 1, 2, 3, 4, and 5 m, and the anchorage depth was 3, 4, 5, 6, and 7 m. The final results showed that the finite element model can effectively simulate the high slope. Increasing the cross-section and anchorage depth of the anti-slide piles could improve the slope stability, but after a certain point, the enhancement effect was no longer significant. Therefore, a cross-sectional diameter of 3 m and an anchorage depth of 5 m were finally selected.

Resumen en Inglés:

Abstract Dynamic compaction is a soil improvement method in which the soil is densified by multiple impacts of a heavy rammer in contact with the ground. Through this procedure, the natural soil increases its shear strength, stiffness, and density, and reduces the potential for swelling, hydraulic conductivity, and susceptibility to liquefaction. During the improvement process, soils undergo induced settlements until they stabilize after a certain number of blows. This process is monitored by the relationship between the compaction energy and the vertical displacement, which generally exhibits a hyperbolic trend that varies mainly as a function of density, as well as the magnitude of the energy, the soil type, the degree of saturation, and the rammer's contact area. Therefore, the objective of this article is to propose a predictive model for induced subsidence based on a hyperbolic equation derived from tests conducted on a frictional cohesive soil typical of Rio Grande do Sul. The results indicated that the model, when calibrated with the parameters λDS (dynamic displacement modulus) and ρmax (Maximum variation of induced subsidence), satisfactorily reproduced the induced subsidence curves observed in the field, making the proposed formulation suitable for both design-stage predictions and field control of dynamic compaction operations.

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Abstract This paper presents a comprehensive study of the stability conditions of a rock mass surrounding a tunnel, using numerical modelling analysis of displacements induced by tunnel construction. The case study focuses on the Boukhadra iron ore mine in Algeria. This research employs empirical equations from literature based on geomechanical classifications to provide the most appropriate geotechnical input data for simulation. In addition to those equations, a novel correlation equation relating the rock mass ratio (RMR) and the rock quality index (Q) was developed. This equation gives a high regression coefficient, revealing a strong correlation (R2) of 0.878. It provides a better estimation of the rock mass characteristics: Young’s moduli (E), Poisson’s ratio (ν), cohesion (c), and friction angle (φ), compared to the existing literature-based correlation equations. The estimated parameters were used to pass from a discontinuous medium to a continuous equivalent, making numerical modelling using finite element method easier. Compared with intact rock and direct equations, the numerical simulation results based on the new equation fit well with the in-situ observations, with predicted displacements remaining within the same order of magnitude as observed deformations, providing more reliable understanding of rock mass behaviour. The new equation proposed in this paper provides a substantial evaluation of the rock mass parameters required for the design process of underground structures when used within their respect acceptable ranges.

Resumen en Inglés:

Abstract Cohesion was defined by Coulomb in the eighteenth century as the strength of a prismatic solid body subjected to a direct tensile test. However, in geotechnics, different meanings have been ascribed to the term cohesion causing conceptual confusion. To distinguish the several meanings assigned to the term cohesion, it is common to find it followed by a complementary term to indicate its meaning. Examples include true cohesion, apparent cohesion, cohesion intercept and Hvorslev's true cohesion. Each of these terms is defined, distinguishing them by their physical interpretation. For this, it was necessary to visit some historical articles from the eighteenth and nineteenth centuries, as well as some articles from the 1930s and 1940s. In addition to the historical aspects presented, the interpretation of rock weathering as a loss of Coulomb’s cohesion and the interpretation of “Hvorslev’s true cohesion” as being of a viscous nature are discussed.