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13 pages, 3564 KiB

Open AccessArticle

An Extended Evaluation of the CERCHAR Abrasivity Test for a Practical Excavatability Assessment

by Markus Kaspar and Christine Latal

Geotechnics 2024, 4(4), 1246-1258; https://doi.org/10.3390/geotechnics4040063 - 9 Dec 2024

Viewed by 183

Abstract

The CERCHAR abrasivity test is a widely used index test in earth and subsurface works, delivering numerical values for abrasion that are critical to the selection of excavation tools, TBM performance or cost and project schedule estimates. The test evaluates the wear of [...] Read more.

The CERCHAR abrasivity test is a widely used index test in earth and subsurface works, delivering numerical values for abrasion that are critical to the selection of excavation tools, TBM performance or cost and project schedule estimates. The test evaluates the wear of the tip of a standardized metal pin after a scratch test on a rock surface. However, excavatability is not considered in this test. The present study presents an approach to assessing the material removal of a rock specimen due to the scratching action of a steel pin. The concept is tested for a broad range of sedimentary, metamorphic and igneous rocks. The volume of removed rock material is determined by measuring the width of the scratch groove and assuming an idealized trapezoid geometry. The CAI and volumetric removal are used to calculate the CERCHAR abrasivity ratio (CAR), and the results are in good agreement with those from the literature where specialized equipment was used. A classification scheme to estimate the excavatability of rock based on the CAI in combination with the material removal of a rock specimen is introduced. Based on the amount of material removed and the wear on the pin, an estimate can be made as to whether the excavation is likely to be economical in terms of time and material costs. The approach does not require additional testing, but rather makes use of the inherent geometry of the steel pin and the scratch groove on the rock specimen. The approach can be implemented as a complementary analysis to the existing CERCHAR test with little additional effort. Full article

(This article belongs to the Special Issue Recent Advances in Geotechnical Engineering (2nd Edition))

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14 pages, 4012 KiB

Open AccessArticle

Machine Learning Analysis of Borehole Data for Geotechnical Insights

by Amichai Mitelman

Geotechnics 2024, 4(4), 1175-1188; https://doi.org/10.3390/geotechnics4040060 - 21 Nov 2024

Viewed by 599

Abstract

This paper explores the use of machine learning (ML) to analyze borehole data aiming to enhance geotechnical insights, using the Gaza Strip as a case study. The data set consists of 632 boreholes, with features including spatial coordinates, ground level, and soil type [...] Read more.

This paper explores the use of machine learning (ML) to analyze borehole data aiming to enhance geotechnical insights, using the Gaza Strip as a case study. The data set consists of 632 boreholes, with features including spatial coordinates, ground level, and soil type per depth. A random forest (RF) classification model was applied to predict soil types, achieving an accuracy of approximately 75%. Notably, the model retained this accuracy even when the data set size was reduced to 30%, suggesting predictable subsurface conditions over large areas. A comparative analysis of common misclassifications revealed that errors mostly occurred between similar soil types, indicating the model’s ability to capture meaningful geological patterns. Unsupervised learning using k-means clustering revealed no clear-cut boundaries between clusters, indicating localized geological anomalies despite large-scale predictability. These findings align with the demonstrated stability of the Gaza Tunnel Network (GTN), a vast network of tunnels which was constructed without comprehensive site investigations. This study demonstrates the potential of ML to improve geotechnical assessments and suggests that fewer boreholes may be needed for large-scale projects, offering cost-saving opportunities. For future research, it is recommended to integrate advanced ML tools, including large language models (LLMs) for analyzing qualitative data from borehole logs, and interpretability methods to enhance model explainability, thus enhancing geological understanding and increasing predictive power. Full article

(This article belongs to the Special Issue Recent Advances in Geotechnical Engineering (2nd Edition))

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17 pages, 5858 KiB

Open AccessArticle

Strong-Motion-Duration-Dependent Power Spectral Density Functions Compatible with Design Response Spectra

by Luis A. Montejo

Geotechnics 2024, 4(4), 1048-1064; https://doi.org/10.3390/geotechnics4040053 - 10 Oct 2024

Viewed by 892

Abstract

The development of a suitable set of input ground motions is crucial for dynamic time history analyses. The US Nuclear Regulatory Commission (NRC) requires that these motions generate response spectra closely matching the plant’s design spectrum. Additionally, the NRC recommends verifying the motions’ [...] Read more.

The development of a suitable set of input ground motions is crucial for dynamic time history analyses. The US Nuclear Regulatory Commission (NRC) requires that these motions generate response spectra closely matching the plant’s design spectrum. Additionally, the NRC recommends verifying the motions’ power spectral densities (PSDs) against a target function to ensure sufficient energy across all frequencies. Current NRC guidelines in Standard Review Plan (SRP) provide a general method for creating target PSDs for any design spectrum. However, this method does not explicitly consider the influence of strong motion duration on the relationship between PSD and response spectrum. This article proposes an improved approach that incorporates the expected strong motion duration into the target PSD generation process. The method first constructs a Fourier amplitude spectrum (FAS) compatible with both the design spectrum and the expected strong motion duration. Subsequently, a large set of synthetic motions based on this FAS is used to construct the target PSD function. It is shown that current target PSD functions tabulated in SRP 3.7.1 implicitly infer an expected strong motion duration of approximately 9 s. The proposed method can be used to construct target PSDs tailored to different strong motion durations. Full article

(This article belongs to the Special Issue Recent Advances in Geotechnical Engineering (2nd Edition))

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29 pages, 8605 KiB

Open AccessArticle

Monotonic Drained and Undrained Shear Behaviors of Compacted Slightly Weathered Tephras from New Zealand

by Shaurya Sood, Gabriele Chiaro, Thomas Wilson and Mark Stringer

Geotechnics 2024, 4(3), 843-871; https://doi.org/10.3390/geotechnics4030044 - 30 Aug 2024

Viewed by 1321

Abstract

This paper reports and discusses the results of a series of monotonic compression drained and undrained triaxial tests performed on three compacted, slightly weathered silty sand tephras. In total, 18 drained and 18 undrained tests were performed on compacted specimens (at D_c [...] Read more.

This paper reports and discusses the results of a series of monotonic compression drained and undrained triaxial tests performed on three compacted, slightly weathered silty sand tephras. In total, 18 drained and 18 undrained tests were performed on compacted specimens (at D_c ≈ 90 and 100%) isotropically consolidated at confining pressures of 50–200 kPa. It was observed that particle size distribution, weathering state, and mineralogy of the tephra deposits had significant effects on the stress–strain responses, friction angles, stress–dilatancy relations, and critical state characteristics. For instance, the coarser tephra (namely white–grey Kaharoa, that was less affected by weathering processes) showed a primarily dilative response. The effects of chemical composition, namely weathering degree and mineralogy, on geotechnical properties such as friction angle were investigated with an attempt to interlink the two characteristics for heterogeneous tephras. The measured friction angles (ϕ = 32.7°–42.8°), combined with the results of weathering degrees and mineralogical investigations, indicated that silty sand tephras, if properly compacted, are suitable fills for use in typical geotechnical applications. Full article

(This article belongs to the Special Issue Recent Advances in Geotechnical Engineering (2nd Edition))

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17 pages, 3021 KiB

Open AccessArticle

Predicting the Compression Capacity of Screw Piles in Sand Using Machine Learning Trained on Finite Element Analysis

by David Igoe, Pouya Zahedi and Hossein Soltani-Jigheh

Geotechnics 2024, 4(3), 807-823; https://doi.org/10.3390/geotechnics4030042 - 21 Aug 2024

Viewed by 918

Abstract

Screw piles (often referred to as helical piles) are widely used to resist axial and lateral loads as deep foundations. Multi-helix piles experience complex interactions between the plates which depend on the soil properties, pile stiffness, helix diameter, and the number of helix [...] Read more.

Screw piles (often referred to as helical piles) are widely used to resist axial and lateral loads as deep foundations. Multi-helix piles experience complex interactions between the plates which depend on the soil properties, pile stiffness, helix diameter, and the number of helix plates among other factors. Design methods for these piles are typically highly empirical and there remains significant uncertainty around calculating the compression capacity. In this study, a database of 1667 3D finite element analyses was developed to better understand the effect of different inputs on the compression capacity of screw piles in clean sands. Following development of the numerical database, various machine learning methods such as linear regression, neural networks, support vector machines, and Gaussian process regression (GPR) models were trained and tested on the database in order to develop a prediction tool for the pile compression capacity. GPR models, trained on the numerical data, provided excellent predictions of the screw pile compression capacity. The test dataset root mean square error (RMSE) of 29 kN from the GPR model was almost an order of magnitude better than the RMSE of 225 kN from a traditional theoretical approach, highlighting the potential of machine learning methods for predicting the compression capacity of screw piles in homogenous sands. Full article

(This article belongs to the Special Issue Recent Advances in Geotechnical Engineering (2nd Edition))

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25 pages, 1422 KiB

Open AccessArticle

A Parametric Study of the Dynamic Soil–Structure Interaction for Shear Vulnerable Structures with Nonlinear Finite Element Modelling

by Ambrosios-Antonios Savvides

Geotechnics 2024, 4(3), 693-717; https://doi.org/10.3390/geotechnics4030037 - 4 Jul 2024

Viewed by 1119

Abstract

In precedent years mostly, though rarely nowadays, shear deformable structures were constructed across the globe. Also, the soil is deformed as a shear cantilever, which means that the shear forces and stresses are more prominent than the respective normal forces and stresses; thus, [...] Read more.

In precedent years mostly, though rarely nowadays, shear deformable structures were constructed across the globe. Also, the soil is deformed as a shear cantilever, which means that the shear forces and stresses are more prominent than the respective normal forces and stresses; thus, the dynamic soil–structure interaction of shear deformable bodies is an important aspect to be researched. In this article, the dynamic soil–structure interaction of shear deformable structures is investigated through nonlinear finite element modelling. The goal of this work is to enlighten the qualitative response of both soil and structures, as well as the differences between the sole structure and the soil–structure system. The Athens 1999 earthquake accelerogram is used, which is considered as a palm load (which means a load that is not periodic like the Ricker wavelets), in order to enlighten the importance of the investigation of palm loading. It is demonstrated that the total displacements of the soil–structure system are larger than the case of the sole structure, as expected when taking into account the dynamic soil–structure interaction. However, the residual displacements of the top are larger when a moderate soil thickness is assumed. Moreover, the output acceleration functions over time, comparing the same buildings as the sole building and as the soil-building system, have the same time function, but they are amplified with a constant value. As a consequence, the critical time of the maximum energy flux that is transmitted to the building is not dependent on the dynamic soil–structure interaction. Full article

(This article belongs to the Special Issue Recent Advances in Geotechnical Engineering (2nd Edition))

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17 pages, 4311 KiB

Open AccessFeature PaperArticle

Risk Assessment in Landslide-Prone Terrain within a Complex Geological Setting at Kadugannawa, Sri Lanka: Implications for Highway Maintenance

by Sunera Mahinsa Pitawala, Harindu Wimalakeerthi and Thomas Heinze

Geotechnics 2024, 4(2), 564-580; https://doi.org/10.3390/geotechnics4020031 - 8 Jun 2024

Viewed by 1186

Abstract

The major highway in Sri Lanka that links the capital, Colombo, with the second capital, Kandy, passes through Kadugannawa, characterized by steep hills. The geological and geomorphological setting of the terrain often leads to slope failures. The objective of this study is to [...] Read more.

The major highway in Sri Lanka that links the capital, Colombo, with the second capital, Kandy, passes through Kadugannawa, characterized by steep hills. The geological and geomorphological setting of the terrain often leads to slope failures. The objective of this study is to interpret the key factors influencing the slope failures that occurred in close proximity at two separate locations with two different slope conditions. Typical local and regional brittle and ductile structures include fault scarps, deep-seated detachments, and variable folding. According to our results, one of the studied locations experienced translational landslides because of weakened basement rock surfaces, hydrophilic clay minerals, and anthropogenic influences, whereas the other location experienced multiple stages of mass movement influenced by inhomogeneous colluvial soil and regional, geological, and hydrogeological conditions. Based on the present study, it can be concluded that geological studies must be carried out within the local area rather than at the regional scale. Otherwise, the constructions for the prevention of landslides in complicated geological settings will fail or may not be used for a long period. Moreover, consideration of future climate change is essential when undertaking construction in challenging terrains. Full article

(This article belongs to the Special Issue Recent Advances in Geotechnical Engineering (2nd Edition))

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18 pages, 2969 KiB

Open AccessArticle

The Swelling–Shrinkage Properties of Intact and Disturbed Clayey and Marly Soils: The Density Effect

by Lamis Makki, Myriam Duc, Thibault Coppée and Fabien Szymkiewicz

Geotechnics 2024, 4(2), 512-529; https://doi.org/10.3390/geotechnics4020028 - 28 May 2024

Viewed by 1259

Abstract

Expansive soils commonly encountered beneath foundations often lead to structural issues inducing expensive repairs. With the increase of the frequency of dry summers and irregular rainfall patterns, the clayey and marly soils become more and more sensitive to shrinking and swelling phenomena. So [...] Read more.

Expansive soils commonly encountered beneath foundations often lead to structural issues inducing expensive repairs. With the increase of the frequency of dry summers and irregular rainfall patterns, the clayey and marly soils become more and more sensitive to shrinking and swelling phenomena. So to find solutions and improve the knowledge on such phenomena especially in temperate countries where the saturation state is considered as the usual soil state, the impact of the soil density on shrinkage was studied by varying the compaction mode and introducing a swelling step before shrinkage. As expected, dynamically or statically compacted clayey or marly soils exhibited high shrinkage deformation when the soil had a low density. The swelling before shrinkage impacted the soil structure but ultimately had a low effect on shrinkage deformation. Swelling deformation was also influenced by density; the denser the soil, the more sensitive the compacted soil became to swelling. Furthermore, compaction modes induced differences in swelling or shrinkage amplitude that couldn’t be explained by microstructural observations. Finally, results demonstrated that intact soil behavior after shrinkage could be extrapolated from swelling–shrinkage tests conducted on remolded soil samples, thus decreasing the cost of field investigations. Full article

(This article belongs to the Special Issue Recent Advances in Geotechnical Engineering (2nd Edition))

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29 pages, 6138 KiB

Open AccessArticle

An Investigation into the Utility of Large Language Models in Geotechnical Education and Problem Solving

by Liuxin Chen, Amir Tophel, Umidu Hettiyadura and Jayantha Kodikara

Geotechnics 2024, 4(2), 470-498; https://doi.org/10.3390/geotechnics4020026 - 9 May 2024

Cited by 2 | Viewed by 1796

Abstract

The study explores the capabilities of large language models (LLMs), particularly GPT-4, in understanding and solving geotechnical problems, a specialised area that has not been extensively examined in previous research. Employing a question bank obtained from a commonly used textbook in geotechnical engineering, [...] Read more.

The study explores the capabilities of large language models (LLMs), particularly GPT-4, in understanding and solving geotechnical problems, a specialised area that has not been extensively examined in previous research. Employing a question bank obtained from a commonly used textbook in geotechnical engineering, the research assesses GPT-4’s performance across various topics and cognitive complexity levels, utilising different prompting strategies like zero-shot learning, chain-of-thought (CoT) prompting, and custom instructional prompting. The study reveals that while GPT-4 demonstrates significant potential in addressing fundamental geotechnical concepts and problems, its effectiveness varies with specific topics, the complexity of the task, and the prompting strategies employed. The paper categorises errors encountered by GPT-4 into conceptual, grounding, calculation, and model inherent deficiencies related to the interpretation of visual information. Custom instructional prompts, specifically tailored to address GPT-4’s shortcomings, significantly enhance its performance. The study reveals that GPT-4 achieved an overall problem-solving accuracy of 67% with custom instructional prompting, significantly higher than the 28.9% with zero-shot learning and 34% with CoT. However, the study underscores the importance of human oversight in interpreting and verifying GPT-4’s outputs, especially in complex, higher-order cognitive tasks. The findings contribute to understanding the potential and limitations of current LLMs in specialised educational fields, providing insights for educators and researchers in integrating AI tools like GPT-4 into their teaching and problem-solving approaches. The study advocates for a balanced integration of AI in education to enrich educational delivery and experience while emphasising the indispensable role of human expertise alongside technological advancements. Full article

(This article belongs to the Special Issue Recent Advances in Geotechnical Engineering (2nd Edition))

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17 pages, 2058 KiB

Open AccessArticle

Assessment of Bayesian Changepoint Detection Methods for Soil Layering Identification Using Cone Penetration Test Data

by Stephen K. Suryasentana, Brian B. Sheil and Myles Lawler

Geotechnics 2024, 4(2), 382-398; https://doi.org/10.3390/geotechnics4020021 - 4 Apr 2024

Viewed by 1097

Abstract

This paper assesses the effectiveness of different unsupervised Bayesian changepoint detection (BCPD) methods for identifying soil layers, using data from cone penetration tests (CPT). It compares four types of BCPD methods: a previously utilised offline univariate method for detecting clay layers through undrained [...] Read more.

This paper assesses the effectiveness of different unsupervised Bayesian changepoint detection (BCPD) methods for identifying soil layers, using data from cone penetration tests (CPT). It compares four types of BCPD methods: a previously utilised offline univariate method for detecting clay layers through undrained shear strength data, a newly developed online univariate method, and an offline and an online multivariate method designed to simultaneously analyse multiple data series from CPT. The performance of these BCPD methods was tested using real CPT data from a study area with layers of sandy and clayey soil, and the results were verified against ground-truth data from adjacent borehole investigations. The findings suggest that some BCPD methods are more suitable than others in providing a robust, quick, and automated approach for the unsupervised detection of soil layering, which is critical for geotechnical engineering design. Full article

(This article belongs to the Special Issue Recent Advances in Geotechnical Engineering (2nd Edition))

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20 pages, 3161 KiB

Open AccessArticle

Improved Wave Equation Analysis for Piles in Soil-Based Intermediate Geomaterials with LRFD Recommendations and Economic Impact Assessment

by Harish K. Kalauni, Nafis Bin Masud, Kam Ng and Shaun S. Wulff

Geotechnics 2024, 4(2), 362-381; https://doi.org/10.3390/geotechnics4020020 - 1 Apr 2024

Cited by 2 | Viewed by 1410

Abstract

The Wave Equation Analysis of Pile Driving (WEAP) has been widely used to determine drivability, predict static resistance, and assure the integrity of piles in soils. Assigning static and dynamic properties of Soil-based Intermediate Geomaterials (S-IGMs) remains a challenge in WEAP, partly attributed [...] Read more.

The Wave Equation Analysis of Pile Driving (WEAP) has been widely used to determine drivability, predict static resistance, and assure the integrity of piles in soils. Assigning static and dynamic properties of Soil-based Intermediate Geomaterials (S-IGMs) remains a challenge in WEAP, partly attributed to IGMs that act as transition geomaterials between soil and hard rock. Furthermore, reliable static analysis methods for unit resistance predictions are rarely available for driven piles in S-IGMs in the default WEAP method. To alleviate these challenges, this study presents improved WEAP methods for steel piles driven in S-IGMs, including proposed damping parameters and Load and Resistance Factor Design (LRFD) recommendations based on newly developed static analysis methods and the classification of S-IGMs. A back calculation approach is used to generate the appropriate damping parameters for S-IGMs for three distinct subsurface conditions utilizing a database of 34 steel H- and pipe piles. Newly developed WEAP and LRFD procedures are also recommended. Additional independent 22 test pile data are used to compare and evaluate the accuracy and efficiency of the proposed WEAP methods with the default WEAP method. Compared with the default WEAP, bearing graph analysis results revealed that the selected proposed WEAP method, on average, reduces the underprediction of pile resistances by 6% and improves the reliability with a 43% reduction in the coefficient of variation (COV). Calibrated resistance factors for the proposed WEAP method increase to as high as 0.75 compared to the current AASHTO recommendation of 0.50. An economic impact assessment reveals that the proposed WEAP method is more efficient than the default WEAP method as the average difference in steel weight for 32 test piles is 0.06 kg/kN, almost close to zero, reducing the construction challenges in the current engineering practice. Full article

(This article belongs to the Special Issue Recent Advances in Geotechnical Engineering (2nd Edition))

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12 pages, 5425 KiB

Open AccessArticle

An Anchoring Capacity Study Focused on a Wheel’s Curvature Geometry for an Autonomous Underwater Vehicle with a Traveling Function during Contact with Loose Ground Containing Water

by Akira Ofuchi, Daisuke Fujiwara and Kojiro Iizuka

Geotechnics 2024, 4(2), 350-361; https://doi.org/10.3390/geotechnics4020019 - 25 Mar 2024

Viewed by 829

Abstract

The current scallop fishery sector allows many scallops to remain in specified fishing zones, and this process leads to heavy losses in the sector. Scallop fishermen aim to harvest the remaining scallops to reduce their losses. To achieve this, a fisherman must understand [...] Read more.

The current scallop fishery sector allows many scallops to remain in specified fishing zones, and this process leads to heavy losses in the sector. Scallop fishermen aim to harvest the remaining scallops to reduce their losses. To achieve this, a fisherman must understand the scallop ecology on the seafloor. In our previous study, we proposed a method for measuring scallops using wheeled robots. However, a wheeled robot must be able to resist disturbance from the sea to achieve high measurement accuracy. Strong anchoring of wheels against the seafloor is necessary to resist disturbance. To better understand anchoring performance, we confirmed the wheel anchoring capacity in water-containing sand in an experiment. In this experiment, we towed fixed wheels on water-containing sand and measured the resistance force acting between the wheel and the sand. Afterward, we considered the resistance force as the wheel anchoring capacity on the water-containing sand. The experimental results capture the tendency for the anchoring capacity of sand with/without water to increase with sinkage. The results also demonstrate that the anchoring capacity of water-containing sand is lower than that of non-water-containing sand. However, the results indicate that when the wheels possess lugs, their presence tends to increase the wheels’ anchoring capacity in water. Full article

(This article belongs to the Special Issue Recent Advances in Geotechnical Engineering (2nd Edition))

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13 pages, 4955 KiB

Open AccessArticle

Impact of Gap-Graded Soil Geometrical Characteristics on Soil Response to Suffusion

by Chen Dong and Mahdi M. Disfani

Geotechnics 2024, 4(1), 337-349; https://doi.org/10.3390/geotechnics4010018 - 21 Mar 2024

Viewed by 1022

Abstract

The phenomenon of fine particle migration through the voids of the granule skeleton under the seepage force is called suffusion. Relative density, original fine particle content, and gap ratio are thought to play vital roles in the suffusion process. This paper investigates the [...] Read more.

The phenomenon of fine particle migration through the voids of the granule skeleton under the seepage force is called suffusion. Relative density, original fine particle content, and gap ratio are thought to play vital roles in the suffusion process. This paper investigates the effect of geometrical characteristics (i.e., original fine particle content, gap ratio, and relative density) on soil structure and mechanical performance (i.e., small strain shear modulus) using the bender element method technique. The small strain shear modulus (G₀) is used as a mechanical parameter to evaluate the shear stress transmission of the soil structure along with the erosion process. The comparison between erosion percentage and vertical strain change suggests the alteration in soil fabric after soil erosion. The G₀ monitoring results show that packings with a higher original fine particle content have a lower G₀ value, whereas the gap ratio and relative density present a positive relationship with G₀. Full article

(This article belongs to the Special Issue Recent Advances in Geotechnical Engineering (2nd Edition))

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21 pages, 9518 KiB

Open AccessArticle

Dissipated Energy and Pore Pressure Generation Patterns in Sands and Non-Plastic Silts Subjected to Cyclic Loadings

by Carmine P. Polito and James R. Martin

Geotechnics 2024, 4(1), 264-284; https://doi.org/10.3390/geotechnics4010014 - 29 Feb 2024

Cited by 2 | Viewed by 782

Abstract

The factors that influence dissipated energy and pore pressure generation patterns with respect to the cycle ratio and dissipated energy ratio were analyzed using the results of cyclic triaxial and cyclic direct simple shear tests. These analyses revealed several interesting differences in pore [...] Read more.

The factors that influence dissipated energy and pore pressure generation patterns with respect to the cycle ratio and dissipated energy ratio were analyzed using the results of cyclic triaxial and cyclic direct simple shear tests. These analyses revealed several interesting differences in pore pressure generation patterns when related to cycle ratio than to dissipated energy ratio. Soils with different pore pressure generation patterns when plotted against the cycle ratio were found to have nearly identical pore pressure generation patterns when plotted against the dissipated energy ratio. The differences exist as the result of the fundamental differences between cycle ratio and dissipated energy ratio. The fundamental difference is that pore pressure generation is directly linked to the process of energy dissipation; it is not inherently linked to cycles of loading. Therefore, to achieve an understanding of the pore pressure response of a soil that is independent of the specifics of the applied loading, one needs to evaluate it in terms of energy dissipation, not in terms of cycles of loading, especially irregular loadings. Full article

(This article belongs to the Special Issue Recent Advances in Geotechnical Engineering (2nd Edition))

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22 pages, 33982 KiB

Open AccessArticle

Stabilization of Shallow Landslides Induced by Rainwater Infiltration—A Case Study from Northern Croatia

by Jasmin Jug, Kristijan Grabar, Anja Bek and Stjepan Strelec

Geotechnics 2024, 4(1), 242-263; https://doi.org/10.3390/geotechnics4010013 - 28 Feb 2024

Cited by 1 | Viewed by 915

Abstract

Climate change brings with it phenomena such as large amounts of rainfall in short periods. Infiltration of rainwater into clayey soils is a common trigger for shallow landslides on slopes. In this way, numerous shallow landslides occur in the area of northern Croatia, [...] Read more.

Climate change brings with it phenomena such as large amounts of rainfall in short periods. Infiltration of rainwater into clayey soils is a common trigger for shallow landslides on slopes. In this way, numerous shallow landslides occur in the area of northern Croatia, and a characteristic example is the landslide “Orehovčak”. To stop the sliding of the destabilized slope, it was necessary to solve the drainage of water that infiltrates the landslide body. For this purpose, detailed geotechnical investigations and monitoring were conducted. Many data were collected at the investigation site, especially soil characteristics and groundwater fluctuations. The surface soil on the slope consists of highly plastic clay, and the sliding surface was created in contact with the solid subsoil of marl, the depth of which varies positionally. The analyses confirmed that water is a slip trigger. To solve the problem, excavations and installation of deep drains were performed. The slope safety factor confirms landslide stabilization, whose calculated value after rehabilitation was Fs = 1.645. Inclinometer readings carried out after remediation show that slope slippage stopped. This confirms that the presented remediation method is very applicable to shallow landslides in northern Croatia and similar landslides around the world. Full article

(This article belongs to the Special Issue Recent Advances in Geotechnical Engineering (2nd Edition))

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13 pages, 2455 KiB

Open AccessArticle

Modelling of Truck Tire–Rim Slip on Sandy Loam Using Advanced Computational Techniques

by William Collings, Zeinab El-Sayegh, Jing Ren and Moustafa El-Gindy

Geotechnics 2024, 4(1), 229-241; https://doi.org/10.3390/geotechnics4010012 - 25 Feb 2024

Viewed by 884

Abstract

Vehicles often experience low tire pressures and high torques in off-road operations, making tire–rim slip likely. Tire–rim slip is undesirable relative rotation between the tire and rim, which, in this study, is measured by the relative tire–rim slip rate. There is little research [...] Read more.

Vehicles often experience low tire pressures and high torques in off-road operations, making tire–rim slip likely. Tire–rim slip is undesirable relative rotation between the tire and rim, which, in this study, is measured by the relative tire–rim slip rate. There is little research on the effect of different terrains on tire–rim slip despite its significance for off-road driving; therefore, this topic was explored through Finite Element Analysis (FEA) simulations. An upland sandy loam soil was modelled and calibrated using Smoothed-Particle Hydrodynamics (SPH), and then a Regional Haul Drive (RHD) truck tire was simulated driving over this terrain, with a drawbar load added to increase drive torque. To examine their effects, five parameters were changed: tire–rim friction coefficient, longitudinal wheel speed, drawbar load, vertical load, and inflation pressure. The simulations showed that increasing the tire–rim friction coefficient and the inflation pressure decreased the tire–rim slip while increasing the vertical and drawbar loads increased the tire–rim slip. Varying the longitudinal wheel speed had no significant effect. Tire–rim slip was more likely to occur on the soil because it happened at lower drawbar loads on the soil than on the hard surface. These research results increased knowledge of tire–rim slip mechanics and provided a foundation for exploring tire–rim slip on other terrains, such as clays or sands. Full article

(This article belongs to the Special Issue Recent Advances in Geotechnical Engineering (2nd Edition))

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15 pages, 584 KiB

Open AccessArticle

Advancing TBM Performance: Integrating Shield Friction Analysis and Machine Learning in Geotechnical Engineering

by Marcel Schlicke, Helmut Wannenmacher and Konrad Nübel

Geotechnics 2024, 4(1), 194-208; https://doi.org/10.3390/geotechnics4010010 - 14 Feb 2024

Viewed by 1283

Abstract

The Ylvie model is a novel method towards transparent Tunnel Boring Machine (TBM) data analysis for tunnel construction. The model innovatively applies machine learning to automate friction loss computation per stroke, enhancing TBM performance prediction in varying geomechanical environments. This research considers the [...] Read more.

The Ylvie model is a novel method towards transparent Tunnel Boring Machine (TBM) data analysis for tunnel construction. The model innovatively applies machine learning to automate friction loss computation per stroke, enhancing TBM performance prediction in varying geomechanical environments. This research considers the complexities of TBM mechanics, focusing on the Thrust Penetration Gradient (TPG) and shield friction influenced by geological conditions. By integrating operational data analysis with geological exploration, the Ylvie model transcends traditional methodologies, allowing for a comprehensible and specific determination of the friction loss towards more precise penetration rate prediction. The model’s capability is validated through comparative analysis with established methods, demonstrating its effectiveness even in challenging hard rock tunneling scenarios. This study marks a significant advancement in TBM performance analysis, suggesting potential for the expanded application and future integration of additional data sources for comprehensive rock mass characterization. Full article

(This article belongs to the Special Issue Recent Advances in Geotechnical Engineering (2nd Edition))

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14 pages, 1832 KiB

Open AccessArticle

Fracture Network Influence on Rock Damage and Gas Transport following an Underground Explosion

by Aidan Stansberry, Matthew R. Sweeney, Jeffrey D. Hyman, Justin Strait, Zhou Lei, Hari S. Viswanathan and Philip H. Stauffer

Geotechnics 2024, 4(1), 180-193; https://doi.org/10.3390/geotechnics4010009 - 31 Jan 2024

Viewed by 1296

Abstract

Simulations of rock damage and gas transport following underground explosions that omit preexisting fracture networks in the subsurface cannot fully characterize the influence of geo-structural variability on gas transport. Previous studies do not consider the impact that fracture network structure and variability have [...] Read more.

Simulations of rock damage and gas transport following underground explosions that omit preexisting fracture networks in the subsurface cannot fully characterize the influence of geo-structural variability on gas transport. Previous studies do not consider the impact that fracture network structure and variability have on gas seepage. In this study, we develop a sequentially coupled, axi-symmetric model to look at the damage pattern and resulting gas breakthrough curves following an underground explosion given different fracture network realizations. We simulate 0.327 and 0.164 kT chemical explosives with burial depths of 100 m for 90 stochastically generated fracture networks. Gases quickly reach the surface in 30% of the higher yield simulations and 5% of the lower yield simulations. The fast breakthrough can be attributed to the formation of connected pathways between fractures to the surface. The formation of a connected damage pathway to the surface is not clearly correlated with the fracture intensity (

P_{32}

) in our simulations. Breakthrough curves with slower transport are highly variable depending on the fracture network sample. The variability in the breakthrough behavior indicates that ignoring the influence of fracture networks on rock damage, which strongly influences the hydraulic properties following an underground explosion, will likely lead to a large underestimation of the uncertainty in the gas transport to the surface. This work highlights the need for incorporation of fracture networks into models for accurately predicting gas seepage following underground explosions. Full article

(This article belongs to the Special Issue Recent Advances in Geotechnical Engineering (2nd Edition))

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23 pages, 4736 KiB

Open AccessArticle

Determination of Constrained Modulus of Granular Soil from In Situ Tests—Part 1 Analyses

by K. Rainer Massarsch

Geotechnics 2024, 4(1), 18-40; https://doi.org/10.3390/geotechnics4010002 - 21 Dec 2023

Cited by 1 | Viewed by 2761

Abstract

Assessing the constrained modulus is a critical step in calculating settlements in granular soils. This paper describes a novel concept of how the constrained modulus can be derived from seismic tests. The advantages and limitations of seismic laboratory and field tests are addressed. [...] Read more.

Assessing the constrained modulus is a critical step in calculating settlements in granular soils. This paper describes a novel concept of how the constrained modulus can be derived from seismic tests. The advantages and limitations of seismic laboratory and field tests are addressed. Based on a comprehensive review of laboratory resonant column and torsional shear tests, the most important parameters affecting the shear modulus, such as shear strain and confining stress, are defined quantitatively. Also, Poisson’s ratio, which is needed to convert shear modulus to constrained modulus, is strain-dependent. An empirical relationship is presented from which the variation in the secant shear modulus with shear strain can be defined numerically within a broad strain range (10⁻⁴–10^−0.5%). The tangent shear modulus was obtained by differentiating the secant shear modulus. According to the tangent modulus concept, the tangent constrained modulus is governed by the modulus number, m, and the stress exponent, j. Laboratory test results on granular soils are reviewed, based on which it is possible to estimate the modulus number during virgin loading and unloading/reloading. A correlation is proposed between the small-strain shear modulus, G₀, and the modulus number, m. The modulus number can also be derived from static cone penetration tests, provided that the cone resistance is adjusted with respect to the mean effective stress. In a companion paper, the concepts presented in this paper are applied to data from an experimental site, where different types of seismic tests and cone penetration tests were performed. Full article

(This article belongs to the Special Issue Recent Advances in Geotechnical Engineering (2nd Edition))

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17 pages, 9673 KiB

Open AccessArticle

Study on the Prediction of Slope Failure and Early Warning Thresholds Based on Model Tests

by Makoto Fukuhara, Taro Uchimura, Lin Wang, Shangning Tao and Junfeng Tang

Geotechnics 2024, 4(1), 1-17; https://doi.org/10.3390/geotechnics4010001 - 20 Dec 2023

Cited by 3 | Viewed by 1425

Abstract

In recent years, slope failure caused by heavy rainfall from linear precipitation bands has occurred frequently, causing extensive damage. Predicting slope failure is an important and necessary issue. A method used to predict the time of failure has been proposed, which focuses on [...] Read more.

In recent years, slope failure caused by heavy rainfall from linear precipitation bands has occurred frequently, causing extensive damage. Predicting slope failure is an important and necessary issue. A method used to predict the time of failure has been proposed, which focuses on the tertiary stage of the creep theory, shown as V = A/(t_r − t), where V is the velocity of displacement, A is a constant, and (t_r − t) is the time until failure. To verify this method, indoor model experiments and field monitoring were used to observe the behavior of surface displacement. Seven cases of laboratory experiments were conducted by changing the conditions in the model, such as materials, the thickness of the surface layer, and relative density. Then, two cases of field monitoring slope failure were examined using this method. The results show that, in the tertiary stage of creep theory, the relationship between tilt angle velocity and the time until failure can be expressed as an inversely proportional relationship. When the tilt angle velocity has reached the tertiary creep stage, it initially ranges from 0.01°/h to 0.1°/h; when near failure, it was found to be over 0.1°/h, so, combining this with previous research results, this is a reasonable value as a guideline for an early warning threshold. Full article

(This article belongs to the Special Issue Recent Advances in Geotechnical Engineering (2nd Edition))

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22 pages, 6729 KiB

Open AccessArticle

Experimental and Numerical Analysis of Laterally Loaded Single- and Double-Paddled H-Piles in Clay

by Abdelrahman Abouziad and M. Hesham El Naggar

Geotechnics 2023, 3(4), 1324-1345; https://doi.org/10.3390/geotechnics3040072 - 15 Dec 2023

Cited by 1 | Viewed by 1432

Abstract

An efficient foundation system of single- or double-paddled H-piles (PHPs), which comprises steel H-piles fitted with specially configured steel plates (paddles), is proposed to support sound walls subjected to wind loading. The lateral responses of single-paddled (SPHPs) and double-paddled H-piles (DPHPs) installed in [...] Read more.

An efficient foundation system of single- or double-paddled H-piles (PHPs), which comprises steel H-piles fitted with specially configured steel plates (paddles), is proposed to support sound walls subjected to wind loading. The lateral responses of single-paddled (SPHPs) and double-paddled H-piles (DPHPs) installed in clay is evaluated using a comprehensive assessment of the foundation performance via a full-scale lateral load testing program, alongside extensive three-dimensional (3D) nonlinear finite element (FE) analysis. The comparison between the calculated and measured responses of the PHPs demonstrates that the developed numerical model accurately depicts the response of the PHPs under lateral load. The validated numerical model is then used to evaluate the effect of the soil consistency on the lateral response and capacity of the PHPs. The influence of the paddles’ configuration on the lateral response and capacity of the PHPs is also evaluated. Furthermore, the change in the PHP lateral stiffness due to adding a second paddle is also examined. Finally, the influence of the plates on the surrounding soil is investigated by analyzing the formation of the strain field around the pile and evaluating the extent of the soil influence zone at different plate-width-to-pile-flange-width ratios (W_p/W_f). The result of this study indicates that adding plates contributes significantly to the lateral capacity of PHPs in clay and reduces the maximum bending moment. The parametric study reveals that the top 5–6 W_p of the soil have a significant effect on the lateral response of the proposed H-pile. Based on the outcomes of the field tests and numerical analysis, optimal geometrical parameters for paddles are proposed. Full article

(This article belongs to the Special Issue Recent Advances in Geotechnical Engineering (2nd Edition))

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15 pages, 6239 KiB

Open AccessArticle

Assessment of a Non-Destructive Testing Method Using Ultrasonic Pulse Velocity to Determine the Compressive Strength of Rubberized Bricks Produced with Lime Kiln Dust Waste

by Joy Ayankop Oke and Hossam Abuel-Naga

Geotechnics 2023, 3(4), 1294-1308; https://doi.org/10.3390/geotechnics3040070 - 1 Dec 2023

Cited by 2 | Viewed by 1485

Abstract

This paper presents a comprehensive study in which non-destructive testing utilizing ultrasonic pulse velocity (UPV), considering both pressure (P) waves and shear (S) waves, was used to assess the compressive strength (CS) of rubberized bricks. These innovative bricks were manufactured by blending lime [...] Read more.

This paper presents a comprehensive study in which non-destructive testing utilizing ultrasonic pulse velocity (UPV), considering both pressure (P) waves and shear (S) waves, was used to assess the compressive strength (CS) of rubberized bricks. These innovative bricks were manufactured by blending lime kiln dust (LKD) waste with ground granulated blast furnace slag (GGBFS), sand, and fine waste tire crumb rubber (WTCR). This study introduces mathematical models to explain the relationships between the results of destructive tests (DTs), specifically compression strength (CS) tests, and non-destructive tests (NDTs) employing UPV. These models were subsequently used to conduct validation exercises to accurately predict the strength of the rubberized bricks produced. The outcomes of the validation tests underscore the effectiveness of the UPV method in predicting the CS of rubberized eco-friendly bricks produced using an LKD-GGBFS blend. Importantly, the prediction using the power model exhibited minimal errors, confirming the utility of the UPV method as a reliable tool for assessing the compressive strength of such sustainable construction materials. This research contributes to advancing the field of eco-friendly construction materials and highlights the practical applicability of non-destructive ultrasonic testing in assessing their structural properties. Full article

(This article belongs to the Special Issue Recent Advances in Geotechnical Engineering (2nd Edition))

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15 pages, 4338 KiB

Open AccessArticle

Embankments Reinforced by Vertical Inclusions on Soft Soil: Numerical Study of Stress Redistribution

by Minh-Tuan Pham, Duc-Dung Pham, Duy-Liem Vu and Daniel Dias

Geotechnics 2023, 3(4), 1279-1293; https://doi.org/10.3390/geotechnics3040069 - 23 Nov 2023

Cited by 3 | Viewed by 2596

Abstract

Constructing embankments over soft soils is a challenge for geotechnical engineers due to large settlements. Among diverse ground-improvement methods, combining piles and geosynthetics (e.g., geosynthetic-reinforced piles, deep cement mixing columns, geotextile-encased columns) emerges as a reliable solution for time-bound projects and challenging ground [...] Read more.

Constructing embankments over soft soils is a challenge for geotechnical engineers due to large settlements. Among diverse ground-improvement methods, combining piles and geosynthetics (e.g., geosynthetic-reinforced piles, deep cement mixing columns, geotextile-encased columns) emerges as a reliable solution for time-bound projects and challenging ground conditions. While stress distribution within pile-supported embankments has been extensively studied, the load transfer efficiency of piled solutions with geosynthetic reinforcement remains less explored. The novelty in this study lies in the investigation of three different inclusion solutions from a common control case in the numerical model considering the role of geosynthetic reinforcement. This study investigates the load transfer mechanisms in embankments supported by various techniques including geosynthetic-reinforced piles, deep cement mixing columns, and geosynthetic-encased granular columns. Two-dimensional axisymmetric finite element models were developed for three cases of embankments supported by vertical inclusions. Numerical findings allow clarification of the soft ground and embankment characteristics which influence the arching and membrane efficiencies. Rigid piles outperform deep cement mixing (DCM) columns and geotextile-encased columns (GEC) in reducing settlements of soft ground. Geosynthetic reinforcements are particularly helpful for rigid pile solutions in high embankments due to their load transfer capability. Additionally, physical properties of fill soil can impact the inclusion solutions, with high shear resistance enhancing the arching effect and lower modulus subsoils showing better arching performance. Full article

(This article belongs to the Special Issue Recent Advances in Geotechnical Engineering (2nd Edition))

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28 pages, 7482 KiB

Open AccessArticle

Modeling Dynamics of Laterally Impacted Piles in Gravel Using Erosion Method

by Tewodros Y. Yosef, Ronald K. Faller, Chen Fang and Seunghee Kim

Geotechnics 2023, 3(4), 1251-1278; https://doi.org/10.3390/geotechnics3040068 - 15 Nov 2023

Cited by 2 | Viewed by 1364

Abstract

Understanding the dynamic interaction between piles and the surrounding soil under vehicular impacts is essential for effectively designing and optimizing soil-embedded vehicle barrier systems. The complex behavior of pile–soil systems under impact loading, attributed to the soil’s nonlinear behavior and large deformation experienced [...] Read more.

Understanding the dynamic interaction between piles and the surrounding soil under vehicular impacts is essential for effectively designing and optimizing soil-embedded vehicle barrier systems. The complex behavior of pile–soil systems under impact loading, attributed to the soil’s nonlinear behavior and large deformation experienced by both components, presents significant simulation challenges. Popular computation techniques, such as the updated Lagrangian finite element method (UL-FEM), encounter difficulties in scenarios marked by large soil deformation, e.g., impacts involving rigid piles. While mesh-free particle and discrete element methods offer another option, their computational demands for field-scale pile–soil impact simulations are considerable. We introduce the erosion method to bridge this gap by integrating UL-FEM with an erosion algorithm for simulating large soil deformations during vehicular impacts. Validation against established physical impact tests confirmed the method’s effectiveness for flexible and rigid pile failure mechanisms. Additionally, this method was used to examine the effects of soil mesh density, soil domain sizes, and boundary conditions on the dynamic impact response of pile–soil systems. Our findings provide guidelines for optimal soil domain size, mesh density, and boundary conditions. This investigation sets the stage for improved, computationally efficient techniques for the pile–soil impact problem, leading to better pile designs for vehicular impacts. Full article

(This article belongs to the Special Issue Recent Advances in Geotechnical Engineering (2nd Edition))

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16 pages, 4632 KiB

Open AccessArticle

Short-Term Predictions of Evaporation Using SoilCover at the Near-Surface of a Mine Waste Pile following Heavy Rainfall Events

by Louis Katele Kabwe and Ward Gordon Wilson

Geotechnics 2023, 3(4), 1180-1195; https://doi.org/10.3390/geotechnics3040064 - 2 Nov 2023

Cited by 1 | Viewed by 1212

Abstract

Accurate measurements and predictions of near-surface soil drying and evaporation following heavy rainfall events are often needed for research in agriculture and hydrology. However, such measurements and predictions at mine waste pile and tailing settings are limited. The prediction of evaporation at mine [...] Read more.

Accurate measurements and predictions of near-surface soil drying and evaporation following heavy rainfall events are often needed for research in agriculture and hydrology. However, such measurements and predictions at mine waste pile and tailing settings are limited. The prediction of evaporation at mine waste piles is essential for many problems in geotechnical engineering, including the design of soil cover systems for the long-term closure of hazardous waste sites, and thus mitigates, for example, the generation of acid mine drainage (AMD) and metal leaching. AMD is one of mining’s most serious threats to the environment. This study investigated the short-term (8 days) and medium-term (27 days) drying rates and evaporative fluxes at the surface and near-surface of the Deilmann South waste-rock (DSWR) pile at the Key Lake uranium mine, northern Saskatchewan, using the gravimetric (GV) method and SoilCover (SC) model, respectively, during and following heavy rainfall events for the environment. The SC simulation results showed that during the weather-controlled stage (Stage I) of the first 5-day period of rainfall events, while the surface was wet, the potential evaporation (PE) was equal to the actual evaporation (AE) (i.e., AE/PE = 1). As the surface became drier on Day 6, the cumulative PE began to separate from the cumulative AE and the surface’s drying rate rapidly diverged from those at the deeper depths. This occurrence signaled the onset of the soil profile property-controlled stage (Stage II). As the drying continued, the surface became desiccated and the slow-rate drying stage (Stage III) was established from Day 7 onward. The SC-simulated AE results were compared to those measured using the eddy covariance (EC) method for the same test period at the DSWR pile in a different study. The comparison showed that the two methods yielded similar AE results, with 18% relative errors. The results of this study provided the opportunity to validate the SC model using actual data gathered under field conditions and to ascertain its ability to accurately predict the PE and AE at the surfaces of mine waste piles. Full article

(This article belongs to the Special Issue Recent Advances in Geotechnical Engineering (2nd Edition))

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27 pages, 8923 KiB

Open AccessArticle

Numerical Modelling and Investigation of the Impact Behaviour of Single Guardrail Posts

by Mohamed Soliman and Roberto Cudmani

Geotechnics 2023, 3(4), 1135-1161; https://doi.org/10.3390/geotechnics3040062 - 30 Oct 2023

Viewed by 1514

Abstract

Vehicle restraint systems are vital hardware elements in road safety engineering. The certification process of a vehicle restraint system includes full-scale crash tests, component testing and numerical simulation of these tests. To achieve reliable crash test simulation results, the soil–post interaction must be [...] Read more.

Vehicle restraint systems are vital hardware elements in road safety engineering. The certification process of a vehicle restraint system includes full-scale crash tests, component testing and numerical simulation of these tests. To achieve reliable crash test simulation results, the soil–post interaction must be modelled to capture the behaviour realistically. There is no standardised approach for modelling the soil–post interaction in the praxis. In this study, the finite element method is utilised to investigate the soil–post response under quasi-static and dynamic impact loading. Two different modelling techniques are applied for this purpose. The first technique is the finite element continuum method, with the soil modelled using the advanced hypoplastic constitutive relation and calibrated using laboratory test data. The second technique is a lumped-parameter model, for which a systematic parameters calibration routine using basic soil properties is introduced. The numerical models are validated using a series of full-scale field tests performed by the authors on single posts in standard road shoulder materials. The performance comparison of the investigated modelling techniques shows that the hypoplastic constitutive relation can capture the post behaviour realistically under different loading conditions using the same parameter set. The introduced lumped-parameter model adequately simulates the post behaviour with high computational efficiency, which is very important when simulating several posts. The conducted parametric study elucidates that the soil’s relative density, the post’s embedment length, and the post-section modulus govern the single post’s lateral load-bearing behaviour and energy dissipation capacity. Full article

(This article belongs to the Special Issue Recent Advances in Geotechnical Engineering (2nd Edition))

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14 pages, 2268 KiB

Open AccessArticle

Correlations for Estimating Coefficients for the Prediction of Maximum and Minimum Index Void Ratios for Mixtures of Sand and Non-Plastic Silt

by Carmine P. Polito

Geotechnics 2023, 3(4), 1033-1046; https://doi.org/10.3390/geotechnics3040056 - 8 Oct 2023

Cited by 1 | Viewed by 1259

Abstract

One common method of estimating e_max and e_min for mixtures of sand and silt requires that the values of several empirical constants be determined. These empirical constants are the filling coefficients, a, and embedment coefficients, b, which can be determined either [...] Read more.

One common method of estimating e_max and e_min for mixtures of sand and silt requires that the values of several empirical constants be determined. These empirical constants are the filling coefficients, a, and embedment coefficients, b, which can be determined either via lab testing or correlations. The study reported here developed simple correlations for estimating the filling and embedment coefficients using readily obtained laboratory data. These models were found to be excellent in producing filling and embedment coefficients that accurately predicted values of the index void ratios for sand and silt mixtures, with most R² values being 0.94 or greater. Full article

(This article belongs to the Special Issue Recent Advances in Geotechnical Engineering (2nd Edition))

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Review

Jump to: Research

24 pages, 8095 KiB

Open AccessReview

Foundations in Permafrost of Northern Canada: Review of Geotechnical Considerations in Current Practice and Design Examples

by João Batista de Oliveira Libório Dourado, Lijun Deng, Yuxiang Chen and Ying-Hei Chui

Geotechnics 2024, 4(1), 285-308; https://doi.org/10.3390/geotechnics4010015 - 4 Mar 2024

Cited by 2 | Viewed by 2591

Abstract

In northern Canada where permafrost is prevalent, a persistent shortage of accessible, affordable, and high-quality housing has been ongoing for decades. The design of foundations in permafrost presents unique engineering challenges due to permafrost soil mechanics and the effects of climate change. There [...] Read more.

In northern Canada where permafrost is prevalent, a persistent shortage of accessible, affordable, and high-quality housing has been ongoing for decades. The design of foundations in permafrost presents unique engineering challenges due to permafrost soil mechanics and the effects of climate change. There is no specific design code for pile or shallow foundations in northern Canada. Consequently, the design process heavily relies on the experience of Arctic engineers. To clearly document the current practice and provide guidance to engineers or professionals, a comprehensive review of the practice in foundation design in the Arctic would be necessary. The main objective of this paper is to provide an overview of the common foundations in permafrost and the geotechnical considerations adopted for building on frozen soils. This study conducted a review of current practices in deep and shallow foundations used in northern Canada. The review summarized the current methods for estimating key factors, including the adfreeze strength, creep settlement, and frost heave, used in foundation design in permafrost. To understand the geotechnical considerations in foundation design, this study carried out interviews with several engineers or professionals experienced in designing foundations in permafrost; the findings and the interviewees’ opinions were summarized. Lastly, in order to demonstrate the design methods obtained from the interviews and review, the paper presents two design examples where screw piles and steel pipe piles were designed to support a residential building in northern Canada, according to the current principles for adfreeze strength, long term creep settlement, and frost heave. The permafrost was assumed to be at −1.5 °C, and the design life span was assumed to be 50 years. The design examples suggested that for an axial load of 75 kN, a 12-m-long steel pipe pile or a 7-m-long screw pile would be needed. Full article

(This article belongs to the Special Issue Recent Advances in Geotechnical Engineering (2nd Edition))

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31 pages, 22851 KiB

Open AccessReview

Relationships between Soil Moisture and Visible–NIR Soil Reflectance: A Review Presenting New Analyses and Data to Fill the Gaps

by Savannah L. McGuirk and Iver H. Cairns

Geotechnics 2024, 4(1), 78-108; https://doi.org/10.3390/geotechnics4010005 - 4 Jan 2024

Cited by 3 | Viewed by 2956

Abstract

The ability to precisely monitor soil moisture is highly valuable in industries including agriculture and civil engineering. As soil moisture is a spatially erratic and temporally dynamic variable, rapid, cost-effective, widely applicable, and practical techniques are required for monitoring soil moisture at all [...] Read more.

The ability to precisely monitor soil moisture is highly valuable in industries including agriculture and civil engineering. As soil moisture is a spatially erratic and temporally dynamic variable, rapid, cost-effective, widely applicable, and practical techniques are required for monitoring soil moisture at all scales. If a consistent numerical relationship between soil moisture content and soil reflectance can be identified, then soil spectroscopic models may be used to efficiently predict soil moisture content from proximal soil reflectance and/or remotely sensed data. Previous studies have identified a general decrease in visible–NIR soil reflectance as soil moisture content increases, however, the strength, best wavelengths for modelling, and domain of the relationship remain unclear from the current literature. After reviewing the relevant literature and the molecular interactions between water and light in the visible–NIR (400–2500 nm) range, this review presents new analyses and interprets new 1 nm resolution soil reflectance data, collected at >20 moisture levels for ten soil samples. These data are compared to the results of other published studies, extending these as required for further interpretation. Analyses of this new high-resolution dataset demonstrate that linear models are sufficient to characterise the relationship between soil moisture and reflectance in many cases, but relationships are typically exponential. Equations generalising the relationship between soil MC and reflectance are presented for a number of wavelength ranges and combinations. Guidance for the adjustment of these equations to suit other soil types is also provided, to allow others to apply the solutions presented here and to predict soil moisture content in a much wider range of soils. Full article

(This article belongs to the Special Issue Recent Advances in Geotechnical Engineering (2nd Edition))

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15 pages, 1933 KiB

Open AccessReview

A Compendious Review on the Determination of Fundamental Site Period: Methods and Importance

by Ahmet Güllü

Geotechnics 2023, 3(4), 1309-1323; https://doi.org/10.3390/geotechnics3040071 - 4 Dec 2023

Cited by 2 | Viewed by 1586

Abstract

It is now well-known that ground motion characteristics can be influenced significantly by local site characteristics. In general, soil characteristics were classified by considering the time-average velocity down to 30 m (V_s30). However, recent studies have showed that the fundamental site [...] Read more.

It is now well-known that ground motion characteristics can be influenced significantly by local site characteristics. In general, soil characteristics were classified by considering the time-average velocity down to 30 m (V_s30). However, recent studies have showed that the fundamental site period is a better proxy than V_s30, or the most complementary parameter to V_s30, for this purpose. Recent earthquakes have also revealed that the largest amplifications occur at the fundamental site period and cause heavy damage or the collapse of structures when they have similar vibrational characteristics with the site’s fundamental period, i.e., resonance. Therefore, many studies in the literature have been performed to determine the fundamental periods of layered soil profiles using different analytical, approximate, and data-driven methods. However, there is a requirement to evaluate these methods by following a systematic procedure. Hence, the reader will receive a comprehensive review of the available procedures for determining the site’s fundamental period of layered soil profiles and their applications at different scales, along with an exploration of current research gaps. Full article

(This article belongs to the Special Issue Recent Advances in Geotechnical Engineering (2nd Edition))

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