Resumo em Inglês:

Abstract This research article presents the results of lateral displacement behaviour of granular columns filled with stiff and flexible recycled materials reinforced in soft soil. In this investigation, finite element analysis was carried out to analyse the lateral displacement response with depth of granular column reinforced into soil stratum. Design parameters of granular columns have been varied including centre to centre spacing varied from 2 m to 4 m and the ratio of depth of columns to depth of soil stratum varied from 0.5 to 1.0. Homogenous soil stratum of 11 m square section has been analysed by varying lateral displacement with depth of columns and variation of principle effective stress with lateral displacement of granular columns. The outcomes reveal that with the increase in depth of granular column, lateral deformation decreases and principle effective stress increases. Similarly, lateral deformation increases for spacing to diameter ratio from 3 to 4 and for spacing to diameter ratio of 2, the zone of high concentrations has been observed due to disproportionate lateral interface among closely spaced columns, resulting in increased lateral deformation and compromised stability. These findings emphasize the critical importance of improving geometrical parameters in the design of granular columns incorporating recycled materials to enhance structural integrity and performance in geotechnical applications.

Resumo em Inglês:

Abstract Chemical soil stabilization by lime addition is used to improve soil properties and to ensure a suitable performance of natural soil. Sometimes chemical and granulometric stabilization combined is required to meet the requirements imposed by the geotechnical design. In this context, reusing waste materials in large-scale projects, besides improving the characteristics of the soil, can reduce the environmental impact of irregular disposal. Considering the importance of this issue, this paper presents the results of an experimental study of quarry dust (QD) addition on a lime-stabilized lateritic soil. The mixtures were prepared using soil, quarry dust proportions of 25%, 50%, and 75%, and lime contents of 7%, 9%, and 11%. The unconfined compressive strength was evaluated at 7, 14, 21, and 28 days of cure, and wetting-drying cycles were performed after 14 days of cure. The microstructure of samples with 9% lime and 28 days of cure was also considered. Regarding the results, it was observed that incorporating 25% of QD and 9% or 11% of lime into a lateritic soil is a viable material in terms of unconfined compressive strength and durability with better performance than natural soil. However, proportions of 50% and 75% of quarry dust decreased the soil strength. The microstructure of the natural soil and soil with 25% QD presented a more closed and interconnected structure. In contrast, the 50% and 75% QD soil mixtures presented a porous structure. Therefore, the proportion of the quarry dust addition demonstrated a critical parameter to be considered.

Resumo em Inglês:

Abstract The coastal region of Boa Viagem and Icaraí, located in the city of Niterói/RJ, has been the subject of several studies focusing on its geotechnical and geological characteristics, particularly due to the presence of a major fault extending into Guanabara Bay. Reliquiae weak layers are widespread in the local soil, with strength parameters significantly different from those of the surrounding residual soil, therefore commanding the stability conditions of excavations in the area. To support the construction of a new residential building complex near Boa Viagem Hill, several 30 to 40 m deep excavations are planned, with the stability ensured through anchored tieback walls and soil nailing systems. This paper aims to analyze the behavior of two key excavation sections considering the impact of the reliquiae soil layers. A 2D numerical analysis was conducted using Plaxis 2D, applying the Hardening Soil Small Strain constitutive model for all soil layers. Displacement profiles and the evolution of average anchorage loads were assessed. The results showed that the highest lateral displacements were concentrated along the reliquiae weak layers, particularly in the final three-quarters of the excavation, indicating a tendency of bottom heaving. At the same depth, the anchors experienced a 7% increase of the average axial loads by the final construction stage. The loads at the facing connections ranged from 60% to 80% of the maximum mobilized nail loads.

Resumo em Inglês:

Abstract Seismic evaluation of rockfill dams with asphaltic concrete cores remains limited despite their growing use in high-seismicity regions like Iran. This study investigates the seismic performance of the Meijaran dam, a rockfill dam with an asphaltic core, located in Mazandaran, Iran. Fragility curves were developed using incremental dynamic analysis (IDA) in FLAC 2D software, employing the relative crest settlement ratio as the damage index and peak ground acceleration (PGA) as the intensity measure. Fragility curves for minor, moderate, and severe damage states indicate no failure at the Design Basis Earthquake (DBE, 0.3g) and an 80% probability of minor damage at the Maximum Credible Earthquake (MCE, 0.5g), with no moderate or severe failure expected. These findings highlight the dam’s resilience, attributed to its robust rockfill materials and flexible asphaltic core. The results provide critical insights for enhancing seismic design, retrofitting strategies, and safety assessments of asphaltic core rockfill dams in earthquake-prone regions, contributing to improved infrastructure resilience.

Resumo em Inglês:

Abstract This paper proposes to construct three-dimensional geological-geotechnical models using the geostatistical interpolation from geomechanics parameters of rocks as lithology and fracturing, plus Rock Designation Quality and Rock Mass Rating classification systems. Generally, the geostatistical interpolation is used to analyze the mining, but this project aims to optimize the prediction of the geological conditions during the initial assessment for infrastructure projects. In this way, the correct predictions of the geological conditions allow us to minimize the inherent risks of failures in the predictability of the structural and geometric patterns of the rocky mass in depth. The proposed procedure aims to ensure the safety of the workers during a complex enterprise. The control of the expenses, as well as the enterprise's durability after construction, promotes social, financial, and environmental security. This methodology has been applied using data from the construction of two different sites, located in Minas Gerais state (Brazil). It was used 44 drill data, 28 from site I and 15 from site II. The results of models showed that it is possible to predict the geological conditions using this geostatistical interpolation; it is possible to affirm that geostatistical interpolation has been effective in the evaluation of geomechanical parameters.

Resumo em Inglês:

Abstract The presence of collapsible soils poses a significant risk for foundation pathologies and is prevalent in various parts of the world, including tropical regions. This paper evaluates the behavior of a specific tropical collapsible soil through laboratory tests and field monitoring of foundations over the course of one year. Laboratory results indicate that the soil has a high collapse potential, particularly at stress levels exceeding 200 kPa, where it is considered critically problematic. Field monitoring revealed that external columns experienced settlement increases of up to 2.7 mm following rainfall events. In contrast, internal columns or those protected by concrete surfaces exhibited less seasonal variation in settlement, with changes of around 1 mm. These observations highlight that long-term exposure to moisture can result in undesirable settlement and underscore the need for moisture considerations in foundation design for collapsible soils. Structures that are initially loaded and subsequently exposed to moisture are likely to experience accelerated future settlement, potentially leading to structural pathologies. Therefore, consideration of moisture effects is critical in foundation design to mitigate long-term settlement issues.

Resumo em Inglês:

Abstract The direct simple shear (DSS) test is often employed to assess the undrained strength of fine-grained soils or the liquefaction behavior of coarse soils. Effective strength parameters are not derived from it because the state of stress within the specimen is not considered sufficiently well defined or uniform enough to allow a rigorous interpretation of the results. In the DSS, the failure plane is not imposed, and the principal stresses are not measured, unlike in the direct shear or triaxial tests, respectively. In the past, the DSS was often dismissed because comparisons with other types of tests indicated that it produced lower effective strength parameters. However, this paper presents results of DSS with stacked rings and direct shear tests that are in good agreement with each other. A finite element analysis and Mohr’s circle representations are used to assess the internal stresses and strains in the DSS specimen and to locate the failure plane. Based on these results, a reinterpretation of other works is conducted. It is shown that the stress distribution becomes approximately uniform after the early phases of the shearing, and the inclination of the failure plane can be predicted. It is also discussed how the use of low height-to-diameter ratios may influence the results. Thus, the DSS with stacked rings may be considered suitable to determine effective strength and deformability parameters, provided an appropriate height-to-diameter ratio is employed, and the results can be expected to agree with those from other types of tests.

Resumo em Inglês:

Abstract Geomembranes (GM) have been extensively used for waterproofing applications, and often they are in contact with soil materials or other geosynthetics for mechanical protection. Strength evaluation at the interface between the GM and the contact material is fundamental to ensure a good design that guarantees a low probability of this interface failure. This paper analyses and compares four Artificial Neural Network (ANN) models (varying the number of inputs and hidden layers) and the Random Forest (RF) technique to predict sand/GM interface shear strength based on 495 results from previous investigations. All models were optimized with the Differential Evolution (DE) algorithm. The Coefficient of Determination (R2) and root mean squared error (RMSE) were set as evaluation criteria for the accuracy of the developed models. The results show that RF performs best as a prediction tool for the data analysed. Data correlation and RF feature importance analysis were also conducted, establishing GM asperity height as the most significant variable for the collected data. The results show the great potential of Machine Learning applications for predicting the interface shear strength between sand and geomembranes in geotechnical engineering constructions.

Resumo em Inglês:

Abstract Expansive soils (ES) are prevalent in semi-arid regions, notably in North African countries. Such soils pose significant infrastructure challenges due to their shrink-swell behavior upon moisture variation. Stabilizing ES using tailings offers a dual benefit: enhancing soil properties and addressing tailing disposal concerns. Reusing and recycling mine tailing materials in problematic earthwork applications, such as ES, could mitigate environmental pollution due to mining activities and protect natural resources. This work is the first study to demonstrate the pozzolanic reactivity and mechanical benefits of finely ground Algerian iron ore tailing (IOT) as a standalone stabilizing agent for ES. Soil samples were treated with varying IOT concentrations (8%, 10%, and 12%) and subjected to a series of tests, including sieve analysis, X-ray fluorescence (XRF), scanning electron microscope (SEM), and X-ray diffraction (XRD). Geotechnical properties were assessed through standard Proctor compaction, unconfined compression strength (UCS), free swell, oedometer, and shear strength tests over different curing periods. Results show that the IOT effectively reduces ES expansion and improves the properties by decreasing plasticity index (PI), free swell index (FSI), swelling pressure (Sp), and maximum dry density (MDD), as well as increasing optimum moisture content (OMC), cohesion (C), frictional angle (ϕ) and pH. The mixture with 12% IOT demonstrated the highest improvement in compressive strength, highlighting its efficiency in stabilizing ES. This research proves the ability of IOT as a sustainable stabilizer for ES. It gives a second use to tailing material in geotechnical projects.

Resumo em Inglês:

Abstract Granular encased columns (GECs) with geosynthetic are an effective technique for improving the soft soil foundation of embankments. One of the primary functions of GECs is to increase the bearing capacity of the soil, preventing foundation failure and eliminating the need for berms. GECs increase the soil's bearing capacity, preventing foundation failure, eliminating the need for berms, and increasing the factor of safety. Two methods are recommended to integrate the geosynthetic strength with the original strength of the ordinary granular column: a) using the increased angle of friction (ϕ’sub), or b) using the increased cohesion (c’sub). Laboratory (direct shear tests), numerical (3D modeling) and analytical studies were conducted to investigate the accuracy of using ϕ’sub and c’sub to represent the increased strength parameters attributable to, resulting from to encasement. The results indicate that the strength of the composite column (sand + geosynthetic) can be adequately represented by the ϕ’sub parameter for a wide range of geosynthetic stiffness (J). However, the approach using the c’sub parameter did not yield satisfactory results, even for a broad range of J. Therefore, the use of the ϕ’sub approach is recommended for stability analysis of embankments built on soft soils supported by GECs.

Resumo em Inglês:

Abstract A parametric study using the limit equilibrium method was carried out to evaluate the influence of a berm of cemented tailings on the stability conditions of dry stack tailings storage facilities over different water table configurations. More than 9000 analyses were performed, assuming drained and undrained conditions, examining the effect of variations in the height of the embankment and the width of the reinforcement berm, as well as the strength of the cemented and uncemented tailings materials. Three different configurations of the water table were considered, simulating a normal scenario and the consequences of heavy rainfall or poor drainage. Results provide relevant insights into the factors involved in the stabilization of dry stacked tailings with cemented berms, including a linear relationship between the factor of safety and a normalized berm width. The fitting coefficients of this correlation were also shown to be dependent on uncemented and cemented soil strength parameters. For conditions similar to those considered in this study, these results can be used as a screening tool to obtain initial estimates of berm dimensions and cemented tailings strength.

Resumo em Inglês:

Abstract Deep excavations in soft soils present complex geotechnical challenges, particularly in maintaining stability during the construction process. The low shear strength and high compressibility of these soils often lead to failure mechanisms that require careful analysis. This study introduces a novel Stiffened Deep Soil Mixing retaining wall system with connectors (SDSMC) for deep excavations in soft clay. Using 3D finite element analysis, the performance of the SDSMC wall was evaluated under varying steel column profile orientations, profile sizes (HEA 100, 200, and 300), and connector configurations. Results show 66% reduction in lateral displacement and 64% reduction in ground settlement compared to conventional Deep Soil Mixing walls. Superior performance was achieved when the strong axis of the HEA (H-beam European standard, series A) section was oriented perpendicular to the lateral earth pressure (X-orientation) and with larger profiles (HEA 300). Strategic connector placement, particularly with two connectors positioned at the top and bottom of the steel column, enhanced wall performance by up to 30%. The findings validate the SDSMC system as a cost-effective, robust, and sustainable alternative for urban deep excavations in soft clay conditions, further experimental validation is recommended to confirm its performance under realistic field conditions and to account for factors such as interface behavior, construction tolerances, and long-term soil-structure interaction.

Resumo em Inglês:

Abstract This work explains secondary consolidation and undrained stress relaxation under isotropic (hydrostatic) stress states in saturated plastic soils, using an extended concept of effective stress. Effective stress (σ’) is split into two components: one transmitted by the solid contacts between grains (σ’s), called the solid component, and another transmitted by the highly viscous adsorbed water surrounding the grains (σ’η), called the viscous component. Isotropic secondary consolidation is explained as taking place by the transference of the viscous component to the solid component under constant effective stress, suggesting that volume changes are associated to changes in the solid component and not to changes in effective stress as a whole. Isotropic consolidation tests in which drainage was closed after the “end of primary”, starting an undrained isotropic stress relaxation stage, showed pore pressure increase with time under constant total stress, causing the effective stress to decrease with time, with no water content change. In the light of the extended concept of effective stress, such pore pressure build-up can be shown to be a consequence of the transference of the viscous component to pore pressure. A practical application of this approach is the prediction of the final value of volumetric strain caused by secondary consolidation. A model based on such an extended concept of effective stress is being developed for general stress states, being able to explain time and strain rate phenomena observed in plastic soil behavior, such as creep, shear stress relaxation and strain rate-dependent strength.

Resumo em Inglês:

Abstract This study presents the development of a cost-effective Raspberry Pi-based electric piezocone system for Cone Penetration Testing with pore pressure measurement (CPTu). By utilizing a Raspberry Pi 4B as the data acquisition system (DAS), the proposed system offers a viable alternative to high-cost commercial geotechnical equipment, particularly in developing regions such as Bolivia. The system integrates high-precision sensors to measure tip resistance (qc), sleeve friction (fs), and pore-water pressure (u2), ensuring accurate real-time soil characterization. Field validation demonstrated a strong correlation between the Raspberry Pi-based system and a commercial CPTu, with Pearson’s r coefficients of 0.69 for sleeve friction and 0.59 for tip resistance. The root mean square error (RMSE) for tip resistance was 2.236 MPa. At the same time, for sleeve friction, it was 46.143 kPa, indicating that while the system provides reliable data, further calibration may improve accuracy. The soil classification results identified predominant layers of stiff sand and sand with silt, aligning with conventional CPTu interpretations. The affordability and adaptability of this system make it a practical solution for geotechnical investigations in resource-constrained environments, offering a functional alternative at a significantly lower cost than commercial CPTu systems. The use of open-source technology also enables real-time data monitoring, customization, and potential integration with machine learning for automated soil classification. Future research will focus on refining sensor calibration, enhancing data analytics, and expanding Internet of Things (IoT) capabilities to improve remote monitoring and streamline geotechnical testing applications.

Resumo em Inglês:

Abstract This article reviews geotechnical risk management theories applied to flood scenarios, focusing on the flooding of Rio Grande do Sul in 2024. The research addresses the definition of geotechnical risk, including the concepts of danger, vulnerability, exposure, and consequences. Qualitative and quantitative risk analysis methodologies are explored, such as Failure Mode and Effect Analysis, Fault Tree Analysis, and probabilistic methods, with an emphasis on application in flood situations. Probabilistic modeling, using stochastic models and Monte Carlo simulation, is discussed to predict the behavior of soils and structures, in addition to sensitivity analyses of geotechnical variables. The geotechnical impact of failures during floods, such as landslides and foundation collapses, is assessed, considering the quantification of material and economic damages. Mitigation strategies are presented, including preventive planning, strengthening infrastructure, and increasing the resilience of structures. This research advances geotechnical risk management by establishing an integrated probability-consequence framework that synthesizes qualitative, quantitative, and socioeconomic assessment methodologies. Validated through the 2024 Rio Grande do Sul floods, this approach offers actionable protocols for enhancing infrastructure resilience in flood-prone regions, particularly under climate change intensification.

Resumo em Inglês:

Abstract The search for soil strength and stiffness improvement is essential in geotechnical engineering. Geosynthetic reinforcement has been considered an effective solution, as it increases the stability of geotechnical works and reduces settlement. These materials are used in works that require greater stiffness, as well as shear and tensile strength, such as foundations and retaining walls. Among geosynthetics, microgrids are used to promote the separation and reinforcement of soils. However, because it is a recently developed geosynthetic on the market, little is known about its properties in soil reinforcement structures, especially when compared with other geosynthetics with the same function, highlighting the need for more research. This research aimed to evaluate the improvement in the bearing capacity of soils reinforced with microgrids. As the results of the pressure x settlement curves did not characterise a typical physical failure behaviour, the failure was conventionally defined based on the Décourt stiffness method. Through the analysis of pressure x settlement curves, the behaviour of natural soils was compared with (i) compacted samples and (ii) compacted samples reinforced with three layers of microgrids. This demonstrated the increase in soil bearing capacity and stiffness through these improvement techniques, which was even more significant when microgrids were inserted in the compacted soil sample. The inclusion of microgrids as a reinforcing element is an effective alternative for stabilising foundations. The stiffness curves showed a tendency to stabilise without reaching zero stiffness, which, according to the Décourt method, confirms the absence of physical failure.

Resumo em Inglês:

Abstract The city of Rio de Janeiro, Brazil, regularly experiences landslides triggered by rainfall. To enhance our understanding of critical thresholds, this study analyses two datasets over a period of 24 years (1999 to 2022): rainfall events, from data obtained from 33 city-installed rain gauges and an inventory of landslide occurrence reports from the Geo-Rio Foundation. The dataset comprises 7,019 significant rainfall events, of which 6,481 resulted in landslides. A total of 6,671 landslides occurred during the analyzed period, a total of 14,402 technical inspections were conducted after slope instability assessments were requested by the population. In addition to evaluating rainfall values that lead to landslides, the study analyses the impact of Geo-Rio's slope-stabilization efforts and population growth in landslide-prone areas. Computational techniques were used to manipulate and classify the data, revealing zone-dependent thresholds. A strong correlation is identified between landslide events, rainfall intensity and accumulated rainfall (96-hour period). The results underscore the necessity to improve Rio de Janeiro's early-warning system, considering both rainfall intensity and 96 hours of accumulated rainfall data to predict landslides, with implications for future slope stabilization efforts and urban planning in landslide-prone areas.

Resumo em Inglês:

Abstract The demand for underground construction to support urban development is growing in major metropolitan centers worldwide. As Brazil’s economic hub, São Paulo faces significant infrastructure challenges, prompting the need for expanded underground networks. Understanding the geotechnical characteristics of subsurface materials is therefore essential. In this context, three-dimensional geological modeling tools—widely adopted in the petroleum and mining industries—are increasingly relevant but remain underutilized in civil construction. In contrast, countries such as the United Kingdom and Finland have consistently applied 3D models to support urban tunneling, as seen in the London and Thames Valley projects. This paper presents a portion of a 16.8 km2 3D geological and geotechnical model of the São Paulo Metropolitan Area—specifically for Metro Lines 3 and 4—developed using Leapfrog Geo software. The complete model is based on 703 borehole records provided by the São Paulo Metro Company (CMSP), characterizing the sedimentary basin in which the metro system is located. The software uses an implicit modeling method based on Radial Basis Functions (RBFs), similar to dual kriging. It supports continuous updates without the need for full re-interpretation, enhancing the planning and design of future subway lines. The study also outlines the benefits and challenges associated with the broader adoption of such tools for underground infrastructure projects. This initial model serves as the foundation for a growing geological and geotechnical database designed to support future tunneling initiatives in São Paulo and its surrounding metropolitan region.

Resumo em Inglês:

Abstract This study analyzes the rockfall hazard at Portão do Inferno, located in Chapada dos Guimarães, Mato Grosso (MT), by applying a rockfall risk mapping methodology and its implications for infrastructure work and safety. The objective of the work was to identify areas susceptible to rockfalls and assess the associated risks, considering the local geology and the impacts on highway MT-251. The methodology included Unmanned Aerial Vehicle (UAV)-based aerial surveys, and application of criteria from the Brazilian Geological Service, along with data obtained from the Construction Inspection Report prepared in November 2024. The mapping considered the slope of the terrain to identify critical areas and define hazard zones. The main results indicate that the region has slopes exceeding 50 degrees and fracture systems S1 and S2, which present a high potential for landslides. The study identified unstable blocks that could be removed by highway management and suggested mitigation interventions, including continuous monitoring and the adoption of containment systems. Additionally, it highlighted the importance of vegetation in dissipating the energy of the falling blocks and in stabilizing the slopes. The study concludes that a detailed analysis of geological discontinuities, combined with a continuous monitoring and mitigation system, is essential to reduce risks and avoid high-cost emergency measures. It also reinforces the need to correlate rainfall events with rockfalls to improve prediction and intervention planning.

Resumo em Inglês:

Abstract Incineration is one of the most widely used techniques to manage solid waste worldwide, thereby reducing it by up to 90%. However, this process produces ash, requiring suitable final disposal. Therefore, the aim of this research is to investigate the feasibility of using healthcare solid waste (HCSW) ash as a soil substitute in chemical stabilisation with Portland cement as a sustainable solution to reduce the use of conventional materials. The methodology involves a geotechnical characterisation (Atterberg limits, particle density, granulometric analysis, California Bearing Ratio) and chemical and mineralogical characterization. The mechanical behaviour was analysed using unconfined compressive strength tests in soil-cement mixtures with increasing cement content, in order to obtain an ideal dosage to mix with HCSW ash. According to the results obtained, adding up to 20% HCSW ash to soil-cement mixture (containing 9% cement) using normal energy produced a gain in unconfined compressive strength. In all the mixtures studied, the strength of the mixtures increased and the minimum requirements for pavement layer applications were met. HCSW ash can be used as a soil substitute in the chemical stabilisation with Portland cement, decreasing the use of conventional materials, indicating a feasible final disposal for HCSW ash.

Resumo em Inglês:

Abstract Slope stability calculations are frequently performed based only on deterministic methods, resulting in a value of Factor of Safety (FS). Deterministic procedures disregard the inherent variability of soil and rock properties. The probabilistic approach treats FS as a function of these properties and considers the impact of variability on the safety of geotechnical projects by estimating the values of the Reliability Index (β) and the Probability of Failure (PF). Deterministic and probabilistic analyses were carried out on two important geotechnical case studies: first, the main slope of Cauê open-pit mine, based on two probabilistic methods (FOSM - First Order Second Moment and MCS - Monte Carlo Simulation) applied with two classic Limit Equilibrium procedures (Simplified Bishop and Morgenstern-Price); the second case study is Santa Branca Dam, and was also based on the FOSM and MCS probabilistic methods, with the Simplified Bishop Limit Equilibrium method. The results from both safety analyses suggest that the FOSM method is simpler and more practical than the MCS, while provided lower PF values with more conservative β then the MCS method. The analyses also indicated that the FOSM technique should be applied associated with the Morgenstern-Price method, since this also provided a more conservative result for the Cauê Mine slope. The Santa Branca Dam was only analyzed with the Simplified Bishop method. In conclusion, it is recommended that probabilistic and deterministic analyses be carried out together to provide a relevant decision-making tool for geotechnical safety assessment by associating FOSM and Morgenstern-Price methods.

Resumo em Inglês:

Abstract This paper presents a novel methodology for probabilistic failure risk analysis of earth dams based on the use of event trees. This approach is designed to eliminate low-relevance failure risks, thereby enabling engineers to concentrate on the detailed characterization of critical risks. The proposed methodology integrates probabilistic load characterization, reliability analyses of dam subsystems, and consequence assessments. The application of the method to a dam under construction on the Camanducaia River (São Paulo, Brazil) demonstrated its effectiveness; the filtering process reduced the number of analyzed risks by 67% (from 9 to 3). The quantitative results indicate that piping is the predominant failure mode, exhibiting a failure probability of 9.81×10−6., under standard operating conditions. The probability of overall failure was determined to be 1.02×10−5 for dry weather and 1.12×10−5 for rainy conditions. The number of incremental fatalities ranged from 29 to 51 depending on the reservoir level and failure mode. A review of international guidelines revealed notable discrepancies. Specifically, risks were deemed acceptable under the guidelines of the USBR (2011) and USACE (2014), yet were not permitted under ANCOLD (2003). These findings underscore the notion that low failure probabilities do not invariably align with acceptable risk levels, thereby reinforcing the need for a comprehensive risk evaluation.

Resumo em Inglês:

Abstract One of the greatest challenges of rock and soil studies is acquiring a sufficient number of samples with adequate characteristics. 3D printing, also known as additive manufacturing or rapid prototyping, is an emerging technique that allows researchers to obtain an unlimited number of samples with the desired geometries and properties. Recent studies also indicate that rapid prototyping is better than the traditional methods to create micromodels. 3D printing is a vast field, with many possible techniques and materials. To better understand the benefits, limitations and applications of the current technology, this article did a systematic review of the literature published in recent years. The search was limited to documents published in English between 2014 and 2024. The only inclusion criterion applied was that the study 3D printed soil or rock analogues. After applying this criterion, and removing duplicates or non-relevant results, a total of 66 documents remained for review. It was possible to observe some printers are already able to reach the nanoscale accuracy and create pores at the natural scale. However, their printing time is significantly longer than other printers, and the material used is not suitable for replicating mechanical properties. Even so, printers able to reproduce mechanical and chemical characteristics are not yet capable of reaching that accuracy. It was possible to conclude that the current technology has its applications and is capable of being a useful tool in geotechnics. Nevertheless, there has to be further improvement in the printing technology for it to reach its full potential.

Resumo em Inglês:

Abstract This study investigates the capabilities and reliability of artificial intelligence (AI) tools in estimating the California Bearing Ratio (CBR) for pavement design purposes. The conventional procedure of determining the soaked and unsoaked CBR is time-consuming and cumbersome. Therefore, investigators and scientists developed various AI methods, categorized according to their learning procedure, i.e., machine learning, advanced machine learning, deep learning, and hybrid learning, to compute the soil CBR. This review article compares the performance of the different computational models used in predicting the CBR of soil. It is noted that the performance of these computational models varied due to the use of different databases. Still, the impact of the quality and quantity of the database on predicting the soaked and unsoaked CBR was not analyzed. Additionally, the impact of database multicollinearity on the model's performance was not analyzed. The study demonstrated that the hybrid learning models are more accurate than the deep and machine learning models in predicting the CBR. Still, configuring the hybrid models (model hyperparameters plus optimization algorithm hyperparameters) is complex and creates structural multicollinearity, which affects the models' performance and accuracy. The literature showed that the combined effect of structural and database multicollinearity was not analyzed and reported. Therefore, considering these gaps in the literature study, the investigators and scientists can extend the published research and report some interesting outcomes.