Foundation Construction Research Articles

Bearing Behavior of Large-Diameter Monopile Foundations of Offshore Wind Turbines in Weathered Residual Soil Seabeds

The southeastern rock base sea area is the most abundant wind resource area, and it is also the mainstream construction site of offshore wind farms (OWFs) in China. The weathered residual soil is the main seabed component in the rock base area, which is the important bearing stratum of the offshore wind turbine foundation. Previous studies on the mechanical properties of seabed materials and bearing characteristics of the pile foundations in OWFs have mainly focused on the submarine soil-based seabed, resulting in a lack of direct reference for the construction of offshore wind power in the rocky seabed. Therefore, the mechanical properties of weathered residual soil and the bearing behaviors of monopile foundations are mainly investigated in this study. Firstly, dynamic triaxial tests are conducted on the weathered residual soil, and experiments analyze insight into the evolution law of the hysteresis curve, cumulative strain, and stiffness attenuation. Then, the horizontal loading behaviors of monopile foundations in residual soil are analyzed by numerical simulations; more critically, the service performances under wind and wave coupling loads are evaluated, which provide a direct theoretical basis for the construction and design of offshore wind turbine foundations in rock base seabeds.

Application of a support vector regression model employing meta-heuristic algorithms for estimating pile bearing capacity

ABSTRACT The design of pile foundations hinges significantly on the pile-bearing capacity (PBC), a crucial factor affected by numerous soil features and parameters. Piles serve as a key component in relocating structural loads to the ground, underscoring the need for accurately determining PBC in geotechnical design. While prior research has delved into utilizing artificial neural networks (ANN) for predicting PBC, they encounter shortcomings such as grappling with finding global minima and slow convergence rates. This study introduces Support Vector Regression (SVR) as a machine-learning approach, augmented by two meta-heuristic optimization techniques: the Giant Trevally Optimizer (GTO) and Smell Agent Optimization (SAO), to achieve optimal results. These techniques empower engineers and data scientists to develop more precise and reliable predictive models in geotechnical engineering, ultimately enhancing the safety and efficiency of foundation design and construction. Drawing upon an extensive dataset compiled from previous studies, a predictive model was constructed to estimate PBC using soft computing techniques. The outcomes overwhelmingly favored the SVGT model, a fusion of the SVR model with GTO, demonstrating excellent anticipative capacities with an outstanding R2 value of 0.998 and an impressively low RMSE value of 91.21.

A Multi-Objective Prediction XGBoost Model for Predicting Ground Settlement, Station Settlement, and Pit Deformation Induced by Ultra-Deep Foundation Construction

Building a deep foundation pit in urban centers frequently confronts issues such as closeness to structures, high excavation depths, and extended exposure durations, making monitoring and prediction of the settlement and deformation of neighboring buildings critical. Machine learning and deep learning models are more popular than physical models because they can handle dynamic process data. However, these models frequently fail to establish an appropriate balance between accuracy and generalization capacity when dealing with multi-objective prediction. This work proposes a multi-objective prediction model based on the XGBoost algorithm and introduces the Random Forest Bayesian Optimization method for hyperparameter self-optimization and self-adaptation in the prediction process. This model was trained with monitoring data from a deep foundation pit at Luomashi Station of Chengdu Metro Line 18, which are characterized by a sand and pebble stratum, cut-and-cover construction, and a depth of 45.5 m. Input data of the model included excavation rate, excavation depth, construction time, shutdown time, and dewatering; output data included settlement, ground settlement, and pit deformation at an operating metro station only 5.7 m adjacent to the ongoing pits. The training effectiveness of the model was validated through its high R2 scores in both training and test sets, and its generalization ability and transferability were evaluated through the R2 calculated by deploying it on adjacent monitoring data (new data). The multi-objective prediction model proposed in this paper will be promising for monitoring the data processing and prediction of settlement of surrounding buildings for ultra-deep foundation pit engineering.

A Hierarchical Analysis Method for Evaluating the Risk Factors of Pile Foundation Construction for Offshore Wind Power

To improve the safety level of pile foundation construction for offshore wind power, in this study, the risk indicators of pile foundation construction were evaluated using the analytic hierarchy process (AHP) and comprehensive evaluation methods. The pile foundation construction operation process for offshore wind power mainly includes four phases: preparation for construction, pile sinking, end of construction, and foundation scour protection construction. Pile foundation construction risk indicators are systematically identified as human factors, material factors, management factors, and environmental factors. The most important indicators for pile foundation construction for offshore wind power were evaluated using AHP and comprehensive evaluation methods, which included five indicators: piling equipment, protective equipment, special skills, safety awareness, and emergency management. The four more important indicators are workplace environment, lifting equipment, fire protection systems, and operations. According to the results of our evaluation of the pile foundation construction safety indicators presented herein, corresponding recommendations are made that consider four aspects—human factors, material factors, management factors, and environmental factors. The construction industry should focus on improving the safety measures related to aspects with greater risk indicators. Pile foundation construction for offshore wind power can be evaluated using the method discussed in this paper, allowing industry stakeholders to prioritize and focus on improving safety measures related to aspects with greater risk indicators.

Reviewing extensions and solution methods of the planar Weber single facility location problem

One of the classic foundational constructs of Location Science was proposed by Alfred Weber in 1909. His construct involved finding the location for a single production facility which minimized the sum of weighted distances of transporting the needed raw materials from localized sources along with the sum of weighted distances in delivering the final product to one or more markets.The first objective of this paper is to review the major advancements in this simple classic single facility location problem and its variations. One can find in the literature a very large number of algorithms to solve the standard Weber problem. Some are iterative and others are finite even for geometric Euclidean and rectilinear spaces. Moreover, some schemes are efficient (theoretically) and others are practically quite fast.The second goal of this paper is to show that many extensions of the standard Weber problem can be solved by solving a polynomial number of standard Weber problems. This unifying result implies, in particular, that all these extensions are polynomially solvable since the standard Weber problem can be solved in polynomial time. In addition, with this unifying approach we solve some important planar non-convex Euclidean location problems in polynomial time.

Numerical prediction of ground-borne vibrations due to continuous vibratory driving of circular closed-ended piles

Various types of pile driving work may induce high-intensity ground-borne vibrations. Predicting vibration intensity before adopting mitigation measures is vital for minimizing the impact of vibration on nearby structures and occupants. Vibratory pile driving is a commonly applied foundation construction method. However, numerical simulation models for ground vibrations during a complete process of vibratory driving have rarely been studied. This study introduces an axisymmetric finite element model that utilizes the arbitrary Lagrangian-Eulerian technique to simulate the continuous vibratory driving of a circular closed-ended pile penetrating from the ground surface to a target depth. The model validity was confirmed by assessing the calculated ground vibrations against the findings documented in earlier research. The results showed that the critical penetration depth of piles, at which the maximum peak particle velocity (PPV) occurs, varied with the radial distance and depth of points of interest, contradicting a common preconception. Moreover, the maximum PPV did not always occur on the ground surface across all radial distances. Parametric analysis revealed that an increase in the soil cohesion strength, pile diameter, or soil-pile friction, or a decrease in the driving frequency or soil damping ratio would increase ground vibrations due to vibratory pile driving.

Identifying Legal, BIM Data and Visualization Requirements to Form Legal Spaces and Developing a Web-Based 3D Cadastre Prototype: A Case Study of Condominium Building

Over the past decade, numerous countries and researchers have been investigating the potential of 3D cadastre based on the Building Information Model (BIM). In Türkiye, the General Directorate of Land Registry and Cadastre (GDLRC) has been engaged in the “Production of 3D City Models and Creation of 3D Cadastral Bases Project” since 2018. One of the objectives is to develop 3D (physical) digital building models (and databases) through the digitization of floor plans of architectural drawings. In order to ensure the long-term viability of this project, a new regulation was issued in 2021. This regulation mandates the submission of 3D digital building models to the land registry in order to register condominiums. The future goals of the GDLRC include utilizing the 3D digital building models produced to create legal spaces in condominium buildings for the 3D cadastre. However, no research has yet been carried out for this goal. The objective of this research is to identify the legal and BIM data requirements for deriving legal spaces in condominium buildings, in light of the legislative analysis, and to develop a web-based 3D cadastre visualization prototype (showing both legal spaces and physical objects) based on the requirements obtained from the scientific literature. The result of this research demonstrates that well-structured and annotated BIM data can be used to develop a 3D cadastre prototype that meets the legal requirements in the case of Türkiye. Moreover, it is evident that, although the GDLRC has initiated the construction of a robust foundation for a 3D cadastre based on BIM, further enhancements and resolutions must be implemented from a legal and technical standpoint. It is postulated that the identified requirements and the proposed methodology in this research may assist decision-makers in Türkiye and globally in formulating their strategic plans for a 3D cadastre.

Optimization of spudcan penetration and influence on caisson foundation

The penetration of spudcans have adverse effects on pre-existing bucket foundations during the blade lifting process of offshore wind power systems, which brings uncertainties for the design and construction of bucket foundations. This study employs the Euler-Lagrange method to explore the influence of spudcan penetration on the adjacent caissons in homogeneous clay within a large deformation finite element (LDFE) model. The LDFE model is validated against centrifuge tests data, with good agreement obtained. Parametric study is then conducted to explore, (i) the influence of the angle between vessel and caissons on the movements of the caisson, and (ii) potential influence factors on the movements of the caisson with an optimal angle between the vessel and caissons, including soil properties, dimensions of caisson and spudcan, and the distance between spudcan and caissons. The results show that 60° is the optimal angle between the vessel and caissons that results in the smallest movement of the caisson, and the caisson foundation inclination angle ranges between 0° and 0.025°, when the pile shoe penetration progress ranges between 0.1 and 1.0. An empirical formula is proposed to predict the rotational angle of caisson with the optimal angle. The study establishes a quantitative approach to assess the influence of the spudcan penetration on existing three-caisson jacket foundations, which provides guidance for the design and construction of offshore wind turbine bucket foundations.

Building Safety Evaluation and Improvement for Northern Vietnam Mountainous Environments Empirical Study Combining Japanese Experience with Local Conditions

This study addressed the insufficient structural strength and inadequate disaster resistance in building designs in the mountainous regions of Northern Vietnam. By integrating Japanese construction experience with local conditions, we proposed optimized building structures and simplified safety evaluation methods. Through an analysis of climate, terrain, geological hazards, soil conditions, and construction material costs, building design and foundation construction were optimized, and these optimizations were validated through wind tunnel experiments and finite element analysis. The results indicated that the optimized structures exhibited superior wind load stability, with external wind pressure coefficients ranging from −1.5 to −0.7, compared with the traditional structure’s range of −1 to −3.5. The redesigned foundation improved landslide resistance, reducing excavation and foundation construction costs relative to Japanese methods. The foundation’s safety factor reached 4.42–5.13, surpassing the standard of 2.5, and the retaining wall’s sliding resistance safety factor reached 1.87, exceeding the requirement of 1.5. These enhancements dramatically boosted building safety under extreme weather conditions. This study provides practical solutions for building design in Vietnam’s mountainous regions and serves as a valuable reference for similar research in other developing countries, underscoring significant practical and social implications.

Impact of building topologies on hill slope stability in Aizawl city

In hilly regions like Aizawl city, wherein houses are mostly built on slopes, the layout of building plays a crucial role in slope stability. Building failures in Aizawl often results from a) non-engineered alterations of slopes b) faulty foundation construction without soil investigation or design. Many residents build and reside on slopes without considering the soil characteristics. To address this, a study was conducted to examine the impact of two common building types - step-back buildings and step-back setback buildings on slope stability in Aizawl. Fifty different sites with varying slope geometries were analysed using Limit Equilibrium Method (LEM), considering soil parameters like cohesion, internal friction angle, unit weight, and slope geometry. The study evaluated slope stability under conditions such as free slope, slope with building loads under static and seismic conditions. The study found that sites with lower slope angles generally demonstrated greater stability, but there were cases where steeper slopes showed better stability due to superior shear strength values. Sites with higher cohesion values exhibited better stability in free slope analysis, while those with higher internal friction angles showed better stability under building loads of both static and seismic condition. To validate the above findings, a sensitivity analysis along with a comparative analysis between step-back and step-back setback building types were conducted. The results indicated that step-back setback buildings offered better stability compared to step-back buildings alone. This suggests that implementing step-back setback buildings could significantly improve slope stability in cities like Aizawl.

Influence of Pile Foundation Construction on Existing Tunnels in a Metro Protection Area: Field Test and Numerical Simulation

On the basis of the Fengqi Chaoming project in Hangzhou City, Zhejiang Province, China, this paper investigates the influence of pile foundation construction on the existing tunnels in a metro protection area to ensure the stability and safety of the pile foundation construction in the area of Hangzhou Metro Line 2 through in situ pile tests and numerical simulations. The test results show that the pile foundation construction has a certain influence on the existing metro tunnels, and the degree of influence gradually decreases as the distance between the pile foundation and the metro tunnel increases. The corresponding impact level for the pile foundation at 12 m from the tunnel is 1.06 mm, and that for the pile foundation at 4.9 m from the tunnel is 1.18 mm. Different types of pile foundations also lead to different degrees of influence. The maximum settlement corresponding to triaxial cement mixing piles is 1.89 mm, while the hard-method occlusal piles is 1.18 mm. The monitoring point of the metro tunnel with the smallest distance from the pile foundation experiences the largest deformation, but several sets of deformation data meet the requirements of the deformation control index, indicating that the pile foundation construction is safe and controllable.

Synergistic stabilization of red-bedded mudstone with microbial-geopolymer: An experimental study

To enhance the stabilization effect of microorganisms and metakaolin on red-bedded mudstone filler, an innovative approach was introduced by implementing a synergistic stabilization technology combining microorganisms and geopolymers. The performance of the proposed approach was evaluated using physical, mechanical, and microstructural properties. Under the synergistic stabilization effect of microbial-geopolymer, the presence of cementitious materials increased by 60.80 percent, and longitudinal velocity increased by 6.63 %. furthermore, the surface porosity decreased by 20.52–23.49 %, the unconfined compressive strength increased by 250.00 % (i.e., 1.26 MPa), and the level of disintegration improved from Garde I (strong) to Grade Ⅳ (no disintegration). The synergistic effect of microorganisms and geopolymer ultimately formed a composite cementing structure of calcium carbonate, hydration products, and polymers, effectively enhancing the density and bonding strength between soil particles. The findings of this paper can guide the stabilization of red-bedded mudstone filler in high-speed railway foundation construction.

An Approach of BIM-Based Dynamic Adaptive Zoning for Group Piles Construction Multi-Work Areas

In large-scale pile foundation drilling projects, the absence of digital work area management hampers dynamic construction management, affecting efficiency. This article explores multi-work area management during pile foundation drilling using a BIM parameterized model, focusing on informatization. The results indicate the following: (i) A dynamic zoning method for pile foundation construction using BIM models was developed to support information management systems and address resource allocation challenges amid dynamic construction team changes. (ii) Adaptive zoning methods were proposed, incorporating the dynamic adjustment of construction work areas, including the division of virtual work areas and adaptive adjustment of pile foundation partition parameters. (iii) Work area modeling and zoning were applied on site, with pile foundation modeling aligning with engineering design distribution, and work area zoning accurately reflecting the on-site construction status. (iv) This method enables adaptive synchronization between pile foundation model attributes and work area information, integrating zoning management into the information system to enhance the construction unit’s information management system and digital management level.

Deep learning-based prediction of particle breakage and friction angle of water-degradable geomaterials

Crushed soft rocks are becoming inevitable geotechnical materials for construction of foundations, fill material for transportation infrastructures, and earthen dams for economic and environmental reasons. The contemporary issue is to predict the water-induced disintegration of these non-traditional granular materials and its correlation with the friction angle of these soils. Machine learning techniques offer a viable solution in this context as they are widely used to understand and predict complex phenomena across various applications. In this work, a deep learning technique, artificial neural networks (ANN), was employed to an experimental dataset obtained from torsional shear tests on dry and saturated crushed soft rocks to predict the water-induced particle breakage potential (ID), peak friction angle (PFA), and residual friction angles (RFA). The experimental ID – PFA and ID – RFA correlations were also predicted using ANN model for all the three outputs (ID, PFA, RFA) with very low errors.

Assessing the effects of different foundation base shapes on settlement and heaving in expansive clay: numerical analysis

AbstractThis paper investigates the behavior of shallow foundations with different base shapes on expansive soils under various Stresses conditions and different slopes of the base. Expansive soils are soils that undergo significant volume changes due to variations in moisture content, which can cause severe damage to structures built on them. The shape of the foundation base can influence the magnitude and distribution of the soil pressures, as well as the deformation and cracking of the foundation. The paper presents a numerical analysis using a finite element method with Plaxis 3D. The paper also proposes some recommendations for the optimal design of foundation base shapes on expansive soils. The numerical results show that the foundation base shape has a significant effect on the stress and displacement distributions in the soil and the foundation and that some shapes perform better than others in terms of reducing the soil pressures. The paper provides some useful insights for the design and construction of shallow foundations on expansive soils.

Advances in Design and Construction of Deep Excavations and Foundations in Sri Lanka

Advances in Design and Construction of Deep Excavations and Foundations in Sri Lanka

Mechanical behavior of EICP-treated calcareous sands under high confining pressures

Calcareous sands are widely distributed on the coral reefs, continental shelf, and seashores between 30° north and south latitude and are commonly utilized as filling materials for the construction of artificial islands and infrastructure foundations. In this study, calcareous sands were cemented by enzymatically induced carbonate precipitations (EICP) technique. Drained triaxial tests were conducted on the EICP-treated calcareous sands. Results showed that the specimens with different cementation levels exhibited different responses in mechanical behavior. The differences in the sand fabric after consolidation under a relatively high confining pressure resulted in the untreated specimen exhibiting a higher peak strength compared to the lightly cemented specimen. High confining pressures exhibited a strongly inhibiting effect on dilatancy, which could be counteracted by increasing the cementation level. The EICP-treated specimen could have one or two yield points (smaller-strain and larger-strain yields). For lightly cemented specimens, the smaller-strain yield stress decreased under high confining pressures due to the partial carbonate bonding degradation during consolidation. The stress line of untreated particle breakage (UPB) was a critical boundary to distinguish failure mode in the p’ -q space. For the EICP-treated specimens, the yield stress located above or below the UPB stress line indicates the simultaneous or sequential breakage of the carbonate bonding and sand particles, respectively. Accordingly, the EICP-treated specimen exhibited brittle or ductile properties. Failure mode transformation could be triggered by increasing cementation level or confining pressure.

Geogrid reinforcement for improving bearing capacity and stability of square foundations

Abstract Shallow foundations are often the most economical option for building support, as they distribute structural weight to soil layers, require minimal earthwork, and do not necessitate specialized machinery. The most common type of soil in the city of Karbala is sandy soil. It is granular and loose by nature which has a relatively low bearing capacity. According to previous studies, the soil weakness is one of the problems with shallow foundation construction. Thus, the aim of this study is to improve the properties of the soil using geogrid reinforcement. Three critical parameters are examined, including depth, size, and number of geogrid layers in the soil reinforcement process to increase bearing capacity and decrease soil settling. The effect of geogrid depth (u) was studied by considering four depth ratios (u/B = 0.5, 1.0, 1.5, and 2.0) in order to determine the ideal depth of the geogrid layer, where (B) refers to the width of the footings. The results indicated that a decrease in depth ratio significantly increased the bearing capacity of footings built on reinforced soil layers compared to those built on natural soil, and the settlement reduction ratio (SRR) also increased. The size of the geogrid layer (i.e., width of the geogrid layer (b) was evaluated by evaluating four size ratios (b/B = 1.5, 3.0, 4.5, and 6.0). With an increasing size ratio of the geogrid layer, the bearing capacity ratio (BRC) was significantly improved. Additionally, the study examined the optimal number of geogrid layers, focusing on single and multiple layers with N = 1, 2, 3, and 4. The results showed a higher BRC for footings on reinforced soil layers, as well as a significant rise in SRR with an increase in the number of geogrid layers. Finally, it was concluded that the optimal depth ratio was u/B = 0.5, the size ratio was b/B = 4.5, and reinforced with three geogrid layers, which provided the highest bearing capacity and SRR. The experimental test results were verified by comparing them with those calculated using theoretically developed models. The variation between the experimental and theoretical results is reasonable, confirming that the experimental testing results exhibit a high degree of accuracy.

Pile–Soil Interaction during Static Load Test

Abstract This study highlights the possibility of determining the shear stress distribution along the skin of a pile, which represents skin resistance. Geotechnical engineering is plagued by the challenge of designing appropriate piles as a sufficient foundation construction while being economically justified solution. Static load testing facilitates verification if the pile satisfies these requirements. In most cases, the pile skin resistance is undervalued. This study first introduces the general approach based on static load test results using an appropriate mathematical approach in the presence of linear, vertical shear stress distribution boundary conditions as well as phenomena such as pile shortening and Kirchhoff's principle. Moreover, a scientific approach for pile compression and shear stress distribution is presented. Further, the study expands upon previous work by applying mathematical calculus to displacement piles. The promising results indicate that further work on greater number of piles may lead to a better understanding of pile–soil interaction and a more accurate design process.

Numerical modelling of multiple excavations in an ultra-deep foundation using an enhanced distinct lattice spring model with modified cam clay model

The control of foundation deformation has garnered significant attention. This study focuses on understanding the deformation induced by excavation activities in real foundation construction scenarios. To accurately model the complex geomechanical responses, an enhanced Distinct Lattice Spring Model (DLSM) was developed. The Modified Cam Clay (MCC) model is employed to represent the nonlinear behaviour of the soil. Integration with one-dimensional structure elements is implemented to model support structures and their interactions with the soil. The birth–death particle method is utilized to simulate the excavation process of the foundation. To improve computational efficiency, a CPU-GPU heterogeneous parallel technique is employed. The enhanced DLSM produces consistent results with the finite element method when calculating foundation-bearing capacity and demonstrates relatively close results compared to finite difference methods when analyzing the stability of foundation slopes under different parameters. Finally, a three-dimensional numerical model is established using the proposed DLSM to simulate the deformation of the foundation caused by the excavations. The entire simulation task is divided into twelve stages, involving in-situ stress, a diaphragm wall, ten supporting structures, and ten excavations. A comparative analysis between the MCC model and the ZP (Zienkiewicz-Pande) model is conducted. The findings indicate that the calculation results of the two are consistent in the early stages of excavation, while those calculated by the MCC in the later stages are relatively small. Sensitivity analysis of the MCC parameters using orthogonal analysis reveals that the porosity of the soil has the greatest impact on the deformation of the foundation pit, followed by the slope of the swelling line, while the slope of the critical state line has a minimal impact. This work provides an alternative high-performance tool for engineering-scale deformation analysis of geotechnical underground excavation.