Geotechnical Model Research Articles

Modelling and Dimensioning of a Natural Riprap Protection Dike Against Coastal Erosion on the Djiffère and Joal Spit

This work aims to study the design and modelling of a longitudinal riprap protection at the bottom of the beach in the areas most threatened by coastal erosion on the Djiffère and Joal spits. The choice of design and modelling techniques is based on the geotechnical and geological characteristics of the subgrade. The sizing allowed us to determine all the parameters necessary to quantify the riprap structure to be installed and the results show that it makes it possible to attenuate the energy of the waves but also to reduce their incident heights by 72%. The dike will help reduce the crossing and will act as a protection for the infrastructure located towards the mainland. The conditions of stability are assured, as well as an analysis of the impacts of the project on the sustainable development of the Joal and Djiffère coastline. Modelling with the Plaxis 3D software allowed us to model the dike with ease and to calculate the safety factor (determination of the balance, stability and displacements of the protective dike). It also allowed us to evaluate the sensitivity of the safety factor with respect to these parameters based on the finite element method using the Mohr Coulomb model. It appears that for a total stress of 1067 KPa, we observed a horizontal displacement of 10.19 cm for the rapid drawdown phase, which falls within the range of tolerable deformations for our dike, i.e. less than 20 cm. In this study, the rapid drawdown of the sea level in 5 days had no influence on the safety factor from ΣMsf = 1.861 to the value of the last phase ΣMsf = 1.972 satisfactory for the dike in terms of stability, i.e. less than 1.4. Thus, the rise in sea level has the effect of producing additional deformations. Keywords: Protective dike, dimensioning, drawdown, geotechnical modelling, 3D Plaxis.

Strong Shaking From Past Cascadia Subduction Zone Earthquakes Encoded in Coastal Landforms

AbstractStrong earthquakes along subduction zones are often devastating events, but sparse records along some tectonic margins limit our understanding of seismic hazards. Constraining shaking intensities is critical, especially in subduction zones with infrequent but large‐magnitude earthquakes like the Cascadia Subduction Zone (CSZ), where the lack of recorded ground motions has led to uncertainty in the severity and potential impacts of future earthquakes. Here we fill this observational gap with a novel inventory of quantitative estimates of past shaking intensities from geotechnical modeling of coastal landforms. One hundred fifty‐four deep‐seated landslides and 65 fragile geologic features constrain minimum and maximum peak ground accelerations, respectively. These estimates are broadly consistent with model predictions of M9 ruptures, suggesting strong shaking of 0.4–0.8 g during past CSZ earthquakes. Local discrepancies between our geologic shaking constraints and earthquake simulations may inform past rupture behavior, leading to better predictions of shaking intensity for future earthquakes.

Geotechnical Assessment of Foundation Stability for Preserving the Agrippa Monument at the Acropolis of Athens.

This study focuses on the geotechnical evaluation of the foundation conditions of the Agrippa Monument at the Acropolis of Athens, aiming to propose interventions to improve stability and reduce associated risks. The assessment reveals highly uneven foundation conditions beneath the monument. A thorough collection of bibliographic references and geotechnical surveys was conducted, classifying geomaterials into engineering-geological units and evaluating critical parameters for geotechnical design. Geotechnical models were developed and 3D finite element analyses were performed. The qualitative evaluation of the foundation under static conditions indicates no immediate risk of failure, as no accelerated movement has been observed and the monument's tilt remains well below critical values. Time-dependent settlements are not expected from any clay layers in the artificial fills. However, further soil compaction could occur due to seismic events, water action (causing erosion or voids), or changes in the monument's weight or tilt under static conditions. The study also proposes instrumental monitoring, foundation soil improvement, and water management strategies to enhance the monument's stability and mitigate potential risks.

Development of a novel cylindrical cam shaking table for geotechnical centrifuge modelling

The use of dynamic centrifuge modelling has substantially risen over the years for investigating failure mechanisms, studying the physics-based mechanics of soil–structure systems, and validating numerical tools. Nevertheless, the primary issues associated with the use of servo-hydraulic actuators (presently the prevailing shaking table for a geotechnical centrifuge) are their exorbitant expense, intricate operation, and shaking control. This paper describes the development of a novel cylindrical cam shaker for the newly installed Mark III geotechnical centrifuge facility at Tokyo City University. The cylindrical cam mechanism is activated once the desired voltage is applied by way of the electrical slip rings. The rotation of the cylindrical cam is translated into the linear motion of the follower plate, which then moves the shaker linearly back and forth. A stepwise procedure is developed to determine the voltage required to drive the shaker and achieve the desired earthquake characteristics for a given payload mass and centrifugal acceleration. The performance of the shaker was systematically assessed through a series of dynamic centrifuge experiments at different centrifugal accelerations and payload masses. Finally, the excellent capabilities of the developed mechanical shaker in terms of the repeatability of the base motions were demonstrated using a model example.

What do we mean by a ground model–the Fookes geomodel legacy

The first Glossop lecture by Professor Fookes in 1996 established the importance of the geological model in predicting ground conditions in engineering geology. The concept of the geological model was expanded in his 2000 paper on ‘total geology’, and this becomes the ‘geomodel’ in a 2015 book. Fookes was clear that the a priori geological model/geomodel developed from existing knowledge and site observations and was fundamental to planning and interpreting the ground conditions data that emerged from investigations. A geological model was referred to in the first iteration (2007) of Eurocode 7 and fed into a geotechnical design model. This usage was reaffirmed in 2022 within an overall Engineering Geological Model Framework by IAEG Commission 25. In Hong Kong the 2007 engineering geology manual identified a geological model as feeding into a ground model and then into a geotechnical model. The expression ‘ground model’ has subsequently emerged as providing a synopsis of the ground conditions that feeds into geotechnical design. This is recognised in the second iteration of Eurocode 7 and is in the 2023 CIRIA guidance on Geotechnical Baseline reports. The Society for Underwater Technology 2022 Report refers to the ground model and defines it as a database of available information that encompasses written reports, the database of collated information and the geotechnical risk register. Given these different views it is necessary to agree what constitutes a ground model, as this has important implications for contract documentation and establishing the legal responsibilities of all ground engineering professionals.

Coastal Reclamation Embankment Deformation: Dynamic Monitoring and Future Trend Prediction Using Multi-Temporal InSAR Technology in Funing Bay, China

Reclamation is an effective strategy for alleviating land scarcity in coastal areas, thereby providing additional arable land and opportunities for marine ranching. Monitoring the safety of artificial reclamation embankments is crucial for protecting these reclaimed areas. This study employed synthetic aperture radar interferometry (InSAR) using 224 Sentinel-1A data, spanning from 9 January 2016 to 8 April 2024, to investigate the deformation characteristics of the coastal reclamation embankment in Funing Bay, China. We optimized the phase-unwrapping network by employing ambiguity-detection and redundant-observation methods to facilitate the multitemporal InSAR phase-unwrapping process. The deformation results indicated that the maximum observed land subsidence rate exceeded 50 mm per year. The Funing Bay embankment exhibited a higher level of internal deformation than areas closer to the sea. Time-series analysis revealed a gradual deceleration in the deformation rate. Furthermore, a geotechnical model was utilized to predict future deformation trends. Understanding the spatial dynamics of deformation characteristics in the Funing Bay reclamation embankment will be beneficial for ensuring the safe operation of future coastal reclamation projects.

Case study of adjacent integral bridges supported on continuous secant piled walls

Integral bridges are often the preferred way of construction for short and medium span bridges in the UK. However, the behaviour of integral bridges is influenced by complex soil-structure interaction behaviour that may be cumbersome to predict and analyse when dealing with unusual structural arrangements. This paper presents a case study for the design of two single span bridges carrying a roundabout over a dual carriageway, supported on continuous secant piled walls. One of the bridges is fully integral while the adjacent structure is articulated at one end due to its skew. An alternative detail for the articulated end is proposed, to eliminate soil pressures and settlements at the back of the abutments as well as reduce the risk of water ingress to the bearings. The complex nature of the structural arrangement presented analytical challenges, that were solved by developing an advanced modelling approach, exploring two proposals. The first is to evaluate the geotechnical model for a range of imposed top of abutment displacements from the onset. The second, using unique non-linear springs and derived P-Y curves describes the more realistic variable nature of soil-structure interaction over the length of the walls leading to reduced soil pressures enhancing design feasibility.

Seismic Microzonation and Geotechnical Modeling Studies Considering Local Site Effects for İnegöl Plain (Bursa‐Turkey)

AbstractLocal site effects play a vital role in determining the level of structural damage to the structures built on soil. Therefore, correctly determining the underground layer structure and its physical characteristics in the lateral and vertical directions is essential for the geotechnical model. More information and more accurate results will be obtained if the geotechnical model is evaluated multidisciplinary together with geophysical studies, not only based on drilling results. For this purpose, vertical electric sounding, seismic refraction, microtremor, and mechanical drilling techniques were applied within the scope of geotechnical studies in the İnegöl district of Bursa. The methods were evaluated together, and the geotechnical cross‐sections of the underground were interpreted. In addition, microzonation maps determined from Geophysical parameters were created in the study area. These maps, geotechnical cross‐sections, and microtremor data evaluation results predicted how the study area's buildings and soils would behave under dynamic forces such as earthquakes. As a result, the soils in the study area were mainly saturated with water and had weak strength. Existing or newly constructed engineering structures on such soils are predicted from microzonation maps that will damage both the soils and the buildings in a seven‐magnitude earthquake.

Automated geotechnical logging of core box images using machine learning

ABSTRACT Geotechnical characterization is contingent on reliable data to reduce uncertainty in the conditions of slope walls or underground workings. However, geotechnical data for greenfield and brownfield sites are often limited. The data that are available are often inconsistent and difficult to reliably use to inform the geotechnical domain model. SRK has developed machine learning workflows using deep learning for geotechnical classification of existing core box photographs to provide a reliable and objective data set that can be used to inform rock mass characterization and structural modeling. Conventional geotechnical parameters are often unsuitable for automation due to the reliance on subjective decisions by the logger for interval lengths or defining naturally open versus closed breaks. Three classification systems have been developed: the Core Damage Index (CDI), the Pseudo-RQD, and the Break Frequency. The CDI classifies discrete intervals within the photographs according to the average clast sizes relative to the core diameter to provide a high-resolution view of the variability of damage down a drill hole. Pseudo-RQD and Break Frequency are calculated by mapping the breaks and rubble zones observed on drill core images.

Enhancing 3D geological and geotechnical engineering model of Bangkok subsoil using optimal deep neural network models

Enhancing 3D geological and geotechnical engineering model of Bangkok subsoil using optimal deep neural network models

Integrated Geotechnical Modelling and Real-time Analysis for Predicting Earthquake-Induced Landslides and Rockfalls in the East African Fracture Zone

Background: The East African Fracture Zone (EAFZ) stands as a testament to the dynamic forces of Earth, marked by heightened seismic activity that frequently triggers geotechnical disasters such as landslides and rockfalls. Traditionally, the study of earthquake-induced geological risks has been reactive, with a focus on post-incident analysis. While significant advances have been made in spatial analysis and risk mapping, the capabilities for real-time prediction and proactive mitigation are still limited. Objectives: Current study presents an approach to predicting earthquake-induced landslides and rockfalls in the EAFZ. The aim is to change the perception of the problem by viewing disasters as manageable risks and informing decision-making in urban planning and disaster mitigation strategies. Methods: A combination of geotechnical engineering, remote sensing, artificial intelligence and machine learning, and socio-economic analysis were used to develop a holistic software framework that solves the complex problem of earthquake prediction without any problems. Results: A software model has been developed that includes a dynamic learning component that refines its predictions with new data, allowing for a deeper understanding of geological subtleties and socio-economic impacts. Considerable attention is paid to the tangible consequences of landslides and rockfalls, including human, property and economic losses. Despite the inevitable challenges of data accuracy and natural unpredictability, the proposed approach opens up new possibilities for proactive disaster management. The results demonstrate a transformational step in data-driven geotechnics and highlight the global applicability of the methods proposed in this work. Conclusion: In this investigation, was taken a pioneering stride in the realm of geotechnical hazard analysis and prediction, focusing on the complex terrains of the East African Fracture Zone (EAFZ). The results provided critical insights into the dynamics of geotechnical hazards in the EAFZ, laying the foundation for future innovations and enhanced safety measures in vulnerable communities.

Application of remote sensing/GIS in the appraisal of geotechnical stability of civil engineering structures in cretaceous sedimentary units in Gombe, Northeastern, Nigeria

The increasing urbanization in Gombe township has necessitated the need for a city-wide assessment of the area to ascertain its spatial geotechnical stability. In this study, the geotechnical stability of Gombe township and environs, Northeastern, Nigeria, was appraised using the geospatial approach. Four different thematic maps (lithology, lineament, elevation, and slope) were generated in a GIS environment. Weights were allocated to the subclasses of the thematic maps based on their contribution to the stability of engineering structures. The thematic maps were integrated using ArcGIS 10.3 software to generate a geotechnical stability model of the study area, which was validated through an on-site inspection of the structures in the area. The study area was delineated into three zones: unstable (17.24%), moderate (77.2%), and stable (4.74%). The moderate zones characterised by medium elevation and slope, average lineament density, and underlain by sandstones were the predominant zones in the area. However, the stable and the unstable zones predominate in the western and eastern parts of the study area respectively. The stable zones that occur in the northwestern and southwestern zones of the study area are underlain by the Kerri-Kerri Formation while the poor and unstable areasare underlain by argillaceous materials of the Pindiga Formation. The validation of the model revealed numerous cracked buildings and bridges and a failed bridge in the unstable zones. The moderate stability zones suffer a mixed fortune, having some stable structures in some parts and failing structures in other parts. The buildings in the stable zones, however, are generally devoid of structural cracks.

PRINCIPLES FOR PREPARATION OF GROUND AND DESIGN MODELS RELATED TO ROCK MASSES IN THE LIGHT OF THE SECOND GENERATION OF EUROCODE 7

The article gives elements of methodology for preparation of ground models related to rock masses in the light of the second generation of Eurocode 7 (EC7 2025). The goal is to present state of the art in this field and to discuss procedures in ground modelling for typical rock engineering problems. Proposed methodology is based on earlier knowledge in preparation of engineering geological and geotechnical models developed in Yugoslavia, modified and adopted to newer recomendations in the EC7 2025. Preparation of Ground and Geotechnical Design Model shall be based on results from geotechnical investigations necessary in succesful definiton of Geotechnical Categories (GC) based on a combination of Consequence Class (CC) and Geotechnical Complexity Class (GCC). Practical illustration is done through presentation of several case histories for different types of structures constructed in rock mass media along Macedonian road network or hydrotechnical projects. Some open questions that can be a starting point for further developments are also mentioned.

Constitutive modelling in computational geomechanics – 61st Rankine lecture, British Geotechnical Association, 2023

Constitutive models are an essential part of computational modelling in geotechnics; they are at the heart of almost all theoretical predictions of geotechnical structures. How the stress–strain (and perhaps time) response of soil (and rock) is represented in these mathematical models is usually the key to successful prediction of the behaviour of geotechnical structures. However, the important details of these models, particularly the idealisations that are made, may be poorly or incompletely understood, or ignored, sometimes at significant cost to the unwary analyst. Indeed, the capabilities and the shortcomings of these models, especially the more advanced models, are not always easy to ascertain. In some cases, determination of the values of the input parameters is not straightforward. Consequently, it may be difficult to determine which model to select for a particular task. This paper explores some of the more important developments in the constitutive modelling of soils and addresses some of these issues of potential concern. The need for such models and the various attributes and capabilities that the commonly used models possess are reviewed. Also discussed is the issue of matching a particular model to the geotechnical problem at hand, which model attributes are required and why. The intention is to place emphasis on the physical basis of these models, rather than explore their mathematical complexity in detail. Some of the constitutive models encoded in the software packages used routinely in geotechnical practice are reviewed, and discussion is also provided on their specific limitations. Examples of practical applications, involving the solution of boundary and initial value problems, are described to illustrate both the advantages and some of the limitations of both commonly used and highly advanced constitutive models.

An operational IoT-based slope stability forecast using a digital twin

The paper investigates the combined use of real-time hydrological monitoring, publicly available meteorological data and hydrological and geotechnical numerical modelling, to develop data-driven models to forecast the stability of a slope. This study showcases a first attempt to integrate these critical aspects into a fully automatic Internet of Thing (IoT)-based local landslide early warning system (Lo-LEWS).The paper uses a validated hydrological numerical model, back-calculated over real monitored conditions, to evaluate the slope stability. The factor of safety (FoS) was computed coupling the commercial package GeoStudio, using transient SEEP/W and Slope. The analyses were conducted for 5 different 1-year datasets encompassing both historical (2019–2020, 2021–2022, 2022–2023) and future projections (2064–2065, 2095–2096) of meteorological variables. Daily variation of hydrological and meteorological variables, along with vegetation indicators were used as inputs to train data-driven models, using polynomial regression (PR) and Random Forest (RF), to forecast daily FoS values. The trained models proved to be effective and were employed to forecast slope stability for the rolling three days. To accurately forecast the FoS, it was essential to incorporate forecasted hydrological, meteorological and vegetation variables into the analysis. The hydrological variables used as inputs for the data-driven models are forecasted using an open-source Python package for the analysis of hydrogeological time series, called Pastas (Collenteur et al., 2019). This model uses historical and forecasted meteorological and vegetation conditions to, specifically, replicate and forecast the time series of volumetric water content (VWC) and pore water pressure (PWP). The forecasted hydrological variables from Pastas, the forecasted meteorological variables as well as Leaf Area Index (LAI) are used as inputs for the trained data-driven models to forecast the FoS values.Finally, a web-based platform (WBP) has been created that automatically runs once a day and perform the following actions: 1) fetches measured and forecasted data using APIs, 2) runs rolling three days forecast based on collected hydrological, meteorological and vegetation variables, and 3) sends the forecasted values back to the Norwegian Geotechnical Institute (NGI) data platform, NGI Live, making them available for real-time visualization in online dashboards. If FoS, VWC or PWP threshold values are exceeded, text messages and emails are sent to the system managers, enabling them to take appropriate actions. The successful implementation of this framework is the result of a collaborative effort across diverse expertise areas, including geotechnics, hydrology, meteorology, instrumentation, and informatics.

Numerical Study on Failure Mechanism of Rock Slope Formed by Mudstone at Girdu, Pakistan

Failure analysis of rock slope is a core topic in rock mechanics and geotechnical engineering. This paper simulates the failure mechanism of a rock slope formed by mudstone at Girdu, Pakistan. Initially, site surveys and laboratory experiments were carried out to measure slope geometry and input shear strength properties of the material. The geotechnical structure and model analyzing computer program (GeoSMA3D) was used to determine the stability of the main slippery blocks. A shear strength reduction method was selected in a three-dimensional distinct element code (3DEC) to examine the failure mechanism, the factor of safety (FS), shear strain concentration, and displacement of slope at various monitoring points. Furthermore, the effect of the rock slippery block, slope angle, and slope height on failure modes of slope were assessed. The present results showed that the studied section is prone to big planer failure at both maximum and minimum strength properties. Slope angle and height significantly influenced the failure characteristics of rock slope . It is inferred that these parameters must be precisely considered during slope reinforcement design.

EVALUASI ANALISIS GEOTEKNIK PADA TAMBANG TERBUKA BATUBARA PIT NORTH WEST PT ANAK TAMBANG INDONESIA JOB SITE PT ADIMITRA BARATAMA NUSANTARA, KALIMANTAN TIMUR

On a mine slope there will be a driving force and a resisting force. The mine slope will collapse if the driving force is greater than the resisting force. Thus, the principle of mitigating mine slope failure is to reduce the driving force or increase the resisting force. PT Adimitra Baratama Nusantara intends to develop a new mining area in the North-West area within the IUP area. Therefore, it is necessary to carry out a geotechnical study that focuses on slope stability analysis to support open-pit coal mining plans based on data from geotechnical investigations in the field, secondary data and geotechnical laboratory test data. Geotechnical modeling for slope stability analysis was carried out using the Finite Element Method because the overburden and interburden sedimentary rocks of coal seams are considered to have behavior approaching elasto-plastic, so that it will provide results that are close to the actual situation in the field. Modeling and slope stability analysis of the mine opening design represented by section-01 and section-03 with the height of each opening being 126 m and 119 m shows that the high-wall and low-wall slope designs are not yet stable, so a re-design is necessary. with the mine opening floor simulated at level -110 and level -90.

Geomechanics and Geology of Marine Terraces of the Crotone Basin, Calabria (Italy)

This study investigates the geomechanical behavior of five terrace orders in the Crotone Basin. The purpose is to understand the physical–mechanical parameters of these terraces to determine whether rock or soil mechanics principles should be applied for stability analysis. Samples were collected from each terrace following an extensive field survey. Laboratory analyses were conducted to measure pulse velocities, uniaxial unconfined compressive strength, and compressive strength with truncated conical platens. The findings revealed key physical–mechanical parameters of the rocks, which are crucial for stability assessments. The Crotone Basin, known for its mineral resources such as hydrocarbons and rock salts, has been studied geologically since before the 1950s, but there is a lack of geomechanical data in existing literature. Therefore, the results presented here are novel and provide a basis for future studies on the instability of rocky slopes composed of similar soft rock types. These results will aid in accurate geological–geotechnical model reconstructions. While the findings can be applied to similar cases, it is important to note that each analysis site, despite showing similar phenomena, is unique and requires individual investigation.

Geotechnical risk modeling using an explainable transfer learning model incorporating physical guidance

While Artificial intelligence (AI) has been successfully applied in assessing geotechnical risk, such methods heavily rely on data quality to achieve satisfactory performance, and their results hardly can be interpreted due to their opaque design. With this in mind, this paper aims to address the following research gap: How can we accurately model geotechnical risks using limited data and domain knowledge, and efficiently explain the results of AI model? We develop a physics-guided transfer learning (PGTL) model to enhance the explainability and accuracy of geotechnical risk modeling. With the help of a physical model that simulates the tunnel excavation, a physics-guided dataset with 1000 samples is established and used to train a deep neural network. On these bases, transfer learning is adopted to fuse the features of physics mechanisms and monitoring data, constructing an explainable prediction model of geotechnical risk. To further support risk decision-making, feature relevance techniques are employed to assess the contribution of input parameters to risk. A shield tunnel construction in Wuhan is selected as a case to validate the effectiveness of the proposed method. The PGTL exhibits a more promising accuracy with R2 of 0.777 in contrast to three popular machine learning approaches, and provides insights into parameters that significantly induce risk, enhancing site managers’ understanding of tunnel construction and being conducive to tunnel safety.

2D and 3D numerical modelling for preliminary assessment of long-term deterioration in Irish glacial till geotechnical slopes

ABSTRACT Long-term geotechnical slope deterioration, influenced by weathering and meteorological factors, presents stability challenges to infrastructure. Wetting and drying cycles lead to pore water pressure variations, causing deformations and slope failure. Studies on glacial tills which investigate deterioration in geotechnical slopes focus on variables like pore water pressure, soil water retention, compaction, freeze–thaw cycles and cracking. This research conducts a preliminary assessment of an Irish glacial till-cut slope, establishing a data-driven foundation for long-term slope behaviour studies. Data analysis, geospatial modelling and numerical simulations were performed on a cut slope in Castleblayney (Ireland), considering short-term/undrained and long-term/drained conditions. FLAC/Slope and Scoops3D were used for 2D and 3D slope stability analyses, applying the First-Order Second Moment (FOSM) probabilistic approach to assess how minor soil property changes affect slope stability, including long-term deterioration scenarios. The study underscores the importance of precise instrument placement within Irish glacial till geotechnical cut slopes, particularly at the uppermost part where shallow and deep failures coincide under long-term and short-term scenarios. This informs strategic instrument positioning for accurate slope deterioration investigations. This research lays the groundwork for understanding mechanisms driving geotechnical slope deterioration and provides insights for future studies on geotechnical asset deterioration models in Irish glacial tills.