Deep Foundation Research Articles

Shallow Foundations and Deep Foundations; Drilled Piers, Aggregate Piers and Stone Columns; Design Recommendations, Construction Considerations, and Performance

Shallow Foundations and Deep Foundations; Drilled Piers, Aggregate Piers and Stone Columns; Design Recommendations, Construction Considerations, and Performance

Evaluation and Optimization of the Corner Effect of a Deep Foundation Pit Adjacent to a Subway Tunnel

Evaluation and Optimization of the Corner Effect of a Deep Foundation Pit Adjacent to a Subway Tunnel

Theoretical Basis for Forecasting the Expansion of the Diameter of the Leading Well in Water-Saturated Soil with a Crushed Stone Bored Pile

In the process of construction and operation of buildings and structures located on weak water-saturated clay foundations, there is often a need to change their physical and mechanical properties. Currently, various methods of surface and deep compaction are used to improve the characteristics of weak soils. It is known that in the process of deep compaction, the soil is compressed under the action of radial stress on the wall of the leading well using an auger (in reverse motion), pile foundation technology, a rotor, etc. In this paper, the main attention will be paid to solving the axisymmetric problem of consolidation of a soil cylinder under the influence of radial pressure. The diameter of the well in this case increases by 2–3 times and is filled with working material – sand and gravel mixture. The purpose of this study is to carry out a theoretical analysis based on a different approach to solving the problem of the stress-strain state of weak soil during compaction of weak foundations and determining the required characteristics of the compacted composite massif transformed by a bored crushed stone pile. The results of the study convincingly prove that the technology under consideration, based on the expansion of the diameter of the leading borehole in water-saturated soil using crushed stone pile drains, is one of the most cost-effective and efficient solutions. It can compete with traditional compaction methods and the more expensive use of deep foundations.

Awareness and knowledge of glaucoma among the patients attending a tertiary eye hospital with and without glaucoma diagnosis

Background: Glaucoma, a leading cause of irreversible blindness, remains under-recognized in many regions, including Bangladesh. This study aimed to assess the awareness and knowledge of glaucoma among the patients attending a tertiary eye hospital with and without glaucoma diagnosis. Methods: This cross-sectional study was conducted on 300 individuals attending deep eye care foundation, Rangpur, from April 2023 to September 2023. Informed consent was obtained from eligible participants over 18 years. The questionnaire, available in both English and Bengali, collected demographic data and included questions on glaucoma awareness and knowledge. Data were analysed using SPSS 25, and the chi-square test was applied to determine statistical significance. Results: Among the participants, 34.7% had heard of glaucoma, with doctors/hospitals being the primary source of information. Awareness varied significantly based on age, residency, education, occupation, and income levels. Among those aware of glaucoma, 59.6% had poor knowledge, 33.7% had average knowledge, and only 6.7% had good knowledge. No significant association was found between glaucoma patients and non-glaucoma patients regarding knowledge level. Conclusions: This study revealed a substantial gap in glaucoma awareness and knowledge in Bangladesh. While a notable portion of the population had heard of glaucoma, their understanding of the condition was limited, emphasizing the need for targeted awareness campaigns and improved access to eye care services. Addressing these gaps is crucial for early diagnosis, treatment, and preventing irreversible blindness while reducing the economic burden associated with glaucoma-related healthcare costs.

Analisis Daya Dukung Lateral Bored Pile Ø 80 Cm dengan Menggunakan Uji Beban Lateral dan Menggunakan Metode Elemen Hingga pada Proyek Menara BRI - Medan

Bored pile foundations are deep foundations that are often used in the construction of large construction sites located in dense areas with the consideration of reducing noise and the influence of vibrations that would occur if pile foundations were used. This analysis aims to calculate the lateral bearing capacity of the bored pile foundation based on the results of analytical calculations using the Broms method, the Davisson method, the Chin method, the Mazurkiewich method, and analyzing the displacement of the bored pile foundation based on loading tests in the field. and the results of soil modeling with Allpile and finite element methods with the Mohr-Coulomb soil model, and the Hardening Soil model. Based on the analysis that has been carried out, the ultimate bearing capacity of the bored pile based on SPT data using the Broms method is 18.92 tons, while the results of the interpretation of the loading test using the Davisson method are 18 tons, the Chin method is 18.98 tons, and the Mazurkiewich method is 19 tons. For the large deflection of a single bored pile with a load of 200% with the Allpile program the large deflection that occurs is 4.25 mm and analysis based on FEM PLAXIS 3D using soil modeling with Mohr - Coulomb large deflection of 3.0 mm and soil modeling with Hardening Soil 2.99 mm.

Study on the seismic wave input method for earth-rock dam on overburden foundation with dynamic nonlinearity based on nonlinear artificial boundary

Accurately obtaining the seismic response of earth-rock dams on overburden foundations is crucial for seismic safety assessment and design, and a reasonable seismic input method is necessary. The seismic wave input method based on artificial boundaries is widely used in elastic foundations. However, the overburden with obvious dynamic nonlinearity is an insurmountable obstacle for the traditional method. In this research, relying on a specific earth-rock dam project, the essence of the seismic wave input method for nonlinear foundations is analyzed in detail from equivalent loads and viscous boundaries, respectively. The mechanism of inapplicability of the traditional seismic wave input method is illustrated, and an effective modified method is validated and presented. The research indicated that equivalent loads for the nonlinear dynamic response of the overburden foundation can be accurately acquired with the shear box model. The dynamic parameters of soil can be captured dynamically by the nonlinear viscous coupling boundary. The states of the lateral boundary of the overburden foundation are consistent with the free field precisely with the modified seismic wave input method by combining the shear box model and the nonlinear viscous coupling boundary. A large error will be caused by neglecting the dynamic nonlinear behavior of the overburden foundation, where the maximum deviation of peak acceleration may be over 55 % or more. A numerical model with a relatively small lateral range of overburden foundation will be obtained when the modified seismic wave input method is engaged. Moreover, the computational accuracy is enhanced remarkably, with a maximum deviation of no more than 5 %. This study provides effective theoretical support for seismic analysis and safety assessment of earth-rock dams on deep overburden foundations.

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

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.

Study on the Impact of Deep Foundation Pit Construction on Nearby Elevated Structures—Case Study

Study on the Impact of Deep Foundation Pit Construction on Nearby Elevated Structures—Case Study

Load–displacement behavior of helical pile using Frustum Confining vessel (FCV) and full-scale testing in Babolsar sand

Nowadays, the use of deep foundations in various civil engineering projects, especially in marine and coastal structures, has been increasing. One type of deep foundations are helical pile foundations, which have gained significant attention in recent decades. This research investigates the load–displacement behavior of different helical pile configurations regarding geometry, i.e., helix diameter and spacing ratio (S/D) in two different soil densities under pullout and compressive loading conditions via the FCV-AUT device. Babolsar sand from the southern coast of the Caspian Sea was utilized for advancing this study. Additionally, four full-scale pile tests were conducted on the Caspian Sea coast under both grouted and non-grouted conditions for pullout and compressive loading. The results indicate that increasing the helix diameter, soil density, and S/D ratio enhances the compressive load-bearing capacity. However, in tensile loading, the ultimate load decreases with an increase in the spacing ratio. Furthermore, the grouting process in the three-helix pile exhibits better performance compared to the two-helix pile, potentially increasing the pile capacity up to 30%. In conclusion, the results obtained from the FCV device, utilizing scale theory, have been generalized to the large-scale pile test results in the field, are representative of in agreement and compatible.

Effect of Steel Support Cross-Section and Preloaded Axial Force on the Stability of Deep Foundation Pits

Effect of Steel Support Cross-Section and Preloaded Axial Force on the Stability of Deep Foundation Pits

Deformation Effects of Deep Foundation Pit Excavation on Retaining Structures and Adjacent Subway Stations

Deformation Effects of Deep Foundation Pit Excavation on Retaining Structures and Adjacent Subway Stations

Experimental investigation on the tension lap splices used in the joints of precast RC foundation piles

AbstractThe joints between precast reinforced concrete pile segments in deep foundations are typically mechanically lockable. They include anchor bars embedded inside the ends of each segment, forming lap splices with the main bars. Because of their particular technology, these lap splices are somewhat different from traditional lap splices, as shown in the first part of this paper, where the impact of their specific characteristics on the tensile behavior of the joints is discussed. The experimental section presents the results of 19 tensile tests on these lap splices and compares them with established theoretical models. The roles of various parameters (lap length, type and amount of confining reinforcement, type of anchor bars, and concrete cover thickness) are investigated. One of the major findings indicates a significantly lower lap capacity when using plain‐bar spirals compared to closed‐ribbed stirrups. Additionally, at low stress levels, the models tend to be unconservative. Building on this insight, a modified model is proposed for lap splices provided with plain‐bar spirals.

Study on the coupling effect and construction deformation control of large deep foundation pit groups involving iron considering the coupling effect of seepage stress

Due to factors such as groundwater seepage and soil stress coupling effect, significant deformation and instability problems often occur during the construction process of super large deep excavation groups involving iron, seriously affecting the safety and stability of the project. This article aims to explore the coupling effect of super large deep excavation groups involving railways during the construction process, and how to effectively control construction deformation. This article combines theoretical analysis and numerical simulation to study the coupled effects of seepage and stress during the construction process of super deep excavation groups involving iron. With the help of finite element software, a numerical model of a large and deep excavation group involving iron was established, and the deformation and stress distribution at different construction stages were simulated. The research results indicate that the coupling effect of groundwater seepage and soil stress has a significant impact on the deformation and stability of the super deep excavation group involving iron. Therefore, reasonable construction measures and deformation control methods should be taken during the construction process.

Numerical Simulation of the Influence of a Deep Foundation Pit Adjacent to a Utility Tunnel: Case Study

Numerical Simulation of the Influence of a Deep Foundation Pit Adjacent to a Utility Tunnel: Case Study

Investigation of the Contribution of First Row Rock Anchors to the Retaining System by Variation of Anchor Bond Length

In deep foundation excavations, inclined, prestressed soil/rock anchors are commonly used as lateral support elements. During the construction of multi-row anchored excavation systems, sometimes it may not be possible to manufacture anchors in the first row. This situation is often encountered in the production of rock anchors. The presence of discontinuities, karstic voids, and/or historical water channels in the rock environment where these anchors will be manufactured, hinders the injection of the anchor bond length. Additionally, the presence of hard rock units or igneous intrusions in the rock environment prevents the anchor hole from being drilled to the desired length. The application of anchors that could not be drilled to the desired length or those that could not achieve the desired quality of bond zone injection is canceled and usually left as an empty hole. In this study, the usability of canceled rock anchors in the first row, as at least anchors with a short bond length has been investigated. A rock anchor designed to support a 5.0-meter excavation pit to be created in a weathered rock environment, with a prestressing load of 500 kN and a bond length of 6.0 meters, was analyzed using Plaxis 3D software for situations with shorter bond lengths. Accordingly, the function of the related rock anchor can also be fulfilled by an anchor with a bond length of 4.0 meters. When the bond length is 4.0 meters, the entire anchor bond length operates at full efficiency. In anchors with bond lengths smaller than 4.0 meters, the prestressing load of 500 kN causes pull-out failure. However, for example, an anchor with a bond length of 2.0 meters continued to contribute to the overall stability of the retaining system under the effect of a prestressing load of 250 kN.

Numerical investigation for shear behavior of pretensioned spun precast concrete pile

Pretensioned spun precast concrete (SPC) pile has emerged as a popular solution for deep foundation systems due to its ease of construction, enhanced bearing capacity, and overall cost-effectiveness. However, the hollowness of SPC piles, which reduces their sectional area, may become critical near the pile cap zone, especially in liquefaction scenarios during earthquake events. This study numerically investigates the shear behavior of hollow pre-tensioned SPC piles using the Finite Element (FE) technique. Primarily, the numerical results are validated with the test results of actual SPC piles where they were manufactured by high-strength concrete and high-tensioned steel strands for both with and without spirals. The numerical results show a good agreement with the experimental data in terms of strength, stiffness, and failure pattern for both types of spiral arrangements. The numerically obtained shear capacity is also found to be within close range of the code recommendations. A series of parametric studies have been conducted to understand the influence of essential pile parameters such as spiral’s spacing, effective prestress, number of strands, thickness-to-diameter ratio, concrete strength, and test orientation angle on the shear resistance of SPC pile. The study claimed that the addition of shear reinforcements to SPC piles boosts their shear capability, whereas the addition of strands and angle of test orientation have little effect on the piles' shear resistance. The optimum applied pre-stressing was found in a range of 4–8 MPa. The optimum values of t/d ratios in terms of material savings to shear resistance of the SPC pile fall in a range of 0.20 – 0.30. Morris Sensitivity Analysis (MSA) reveals that effective prestress and pile concrete strength are the most influential parameters of the shear capacity of SPC piles. This study provides important details for the SPC pile's shear design, illustrating its applicability in deep foundations in seismic areas.

Study on Deformation Control of Road-Deep Foundation Pit Passing under Elevated Subway Bridge

This paper focuses on the application of pile foundation underpinning technology in a deep foundation pit of a subway Viaduct Project in Beijing. The study aims to address the engineering characteristics of the project, including a large number of new piles, a wide span of underpinning abutment, a long length of deep foundation pit, and a wide range of influences. This research utilizes field monitoring and numerical simulation methods to investigate the pile foundation underpinnings. The impact and management of road-deep foundation pit construction are considered, as well as their combined effect on subway viaducts and track structures. The primary accomplishments are as follows: (1) By analyzing the data from on-site deformation monitoring, it is evident that the pier exhibits maximum vertical deformation and maximum transverse deformation at the same location. The measuring locations are specifically situated on Pier 7# at the pile foundation underpinning. The maximum vertical and transverse deformations of the track are directly proportional to the maximum deformation of the pier. (2) By comparing the numerical simulation results with the field monitoring data, it is observed that although there is some discrepancy between the two, the deformation trend is largely consistent. This suggests that the numerical simulation analysis method is effective in reflecting the deformation of the bridge and track. (3) Through the numerical model and changing the values of the retaining structure parameters, the sensitivity of the pier deformation near the road foundation pit to the retaining structure parameters is systematically analyzed. The sensitivity of the pier deformation to the foundation pit parameters is as follows: the embedded depth insertion ratio of the retaining pile > the diameter of the retaining pile > the pile spacing.

Human Resource Management in the Transformative Digital Era

Digitalization in human resource management helps companies to modernize HR functions and gives them a competitive edge. At the same time, it requires a change in work style and require changes in demand for HR competencies. Study this aims to introduce the phenomenon of digitalization in literature, explore its current benefits and key risks, and analyze the competencies and role of HR professionals. Innovative strategies that can be applied in human resource management (HRM) to enhance organizational performance in the digital era. With rapid changes in technology and the business environment, organizations need to develop innovative approaches in managing their human resources. This research method is a qualitative research method with a descriptive approach. This research operationally examines various sources of literature relevant to the context of the above research. The data taken, identified in the following order: (1) data collection (2) data sorting (3) data analysis (4) conclusion making. As for data analysis, there is a predetermined sequence in accordance with the empirical steps taken, namely as follows: (1) Examination of data (2) suspected data findings, (3) Data confirmation (4) Diagnosis, (5) Action. The results obtained show that HR professionals tend to be a little reluctant to adopt technology the. The results of this research confirm the importance of digitalization in recent years for human resources and increasing demand for digital skills. Every organization should develop its digital strategy to improve productivity. In the present scenario, DHRM is considered a more significant and growing research topic as well as an important topic for a business organization. With the use of DHR practice and through social media, the internet, AI, and other technology organization can maintain their performance and employees' quality standard for the smooth running of the organization. In exploring "Strategic Human Resource Planning in the Era of Digital Transformation" through the Systematic Literature Review method, this research reveals important findings. Technology integration, especially through artificial intelligence, big data analysis and technology platforms, is proven to be a deep foundation in responsive and adaptive HR planning in the era of digital transformation. The success of this planning also depends heavily on the involvement of key stakeholders, particularly upper management and business units, who contribute to the identification of skills relevant to technological change.

Experimental study on the treatment of deep miscellaneous fill foundation in Xinjiang by vibrating rod compaction method

Currently, the treatment of miscellaneous fill foundations, composed of a mixture of domestic garbage, construction solid waste, and natural soil, presents a significant challenge in urban peripheral engineering construction. This paper discusses the application of vibrating rod compaction technology for foundation treatment in Xinjiang. It evaluates the effectiveness of cross-section vibrating rod compaction equipment in reinforcing fine-grained miscellaneous fill foundations. The study analyzes the impact of construction disturbances caused by the insertion of the vibrating rod, monitoring horizontal stresses at various depths. Both laboratory and field tests show significant improvements: soil dry density increased by 8% to 18%, porosity decreased by 10% to 23%, compression modulus increased by 22% to 246%, and compression coefficient decreased by 8% to 70%. Additionally, cohesion (C) and angle of friction (ɸ) saw increases ranging from 7 to 38% and 3% to 25%, respectively. Below a depth of 3 m, cone tip resistance exceeded 10 MPa, and sidewall friction resistance increased to over 100 kPa, surpassing pre-treatment values. The standard penetration test results doubled stroke length compared to pre-treatment, indicating a substantial improvement in foundation bearing capacity. Surface wave tests before and after treatment showed a 15% increase in wave velocity, reflecting a more compact soil structure. The vibrating rod compaction method is innovative, energy-efficient, environmentally friendly, and economically beneficial, holding great potential for future miscellaneous fill treatments.

The Influence of Concrete Age on the Accuracy of Pile Integrity Testing on Bored Piles Foundation

Abstract Bored pile foundations are defined as deep foundations in the form of an elongated tube with a specific diameter made of reinforced concrete installed using the drilling method and in-situ casting concrete. The cast in-situ process in bored holes with a deep elevation below the ground surface can potentially cause integrity problems, such as voids, segregation, fracture, necking, bulging, and other concrete defects. Currently, many non-destructive test methods are available to ensure the quality of the bored pile; one is the Low Strain Integrity Testing method, also known as Pile Integrity Testing (PIT). ASTM recommends that PIT should be carried out no sooner than 7 days after casting or the strength of the concrete has reached a minimum of 75,0% of its design strength. In fact, the PIT test is carried out before the concrete’s age and/or its strength is achieved, considering the limited construction time. This could lead to misinterpretation of the PIT test results and inaccurate identification of the bored pile defect locations. The study aims to determine the effect of concrete age on the accuracy of bored pile defect locations on a laboratory scale. The test model consisted of four bored piles with a diameter of 0,3 meters and a depth of 2,0 meters, which were cast using reinforced concrete with a design strength of fc’ 30 MPa. The PIT was performed at <7, 14, and 28 days of concrete age, and then the confusion matrix method was used to create a binary classification model to determine the accuracy of the defect location. The defect locations were visually observed and validated by dismantling the test model after 28 days of casting. The results showed that the accuracy of identifying the location of concrete defects was not affected by the age of the concrete but was determined by the compressive strength of the concrete during testing. Referring to the F-score, bored piles with concrete strength >75,0% of the design accurately identify defect locations above 84,21%. On the other hand, bored piles with concrete strength <75,0% design resulted in accuracy below 66,67%.