Bearing Capacity Of Foundation Research Articles

Analysis of time-dependent bearing capacity of pile foundation in marine soft soil region considering non-Darcy flow

Due to the deviation of pore water seepage in marine soft soils from Darcy flow under low hydraulic gradients, existing methods face challenges in accurately calculating the time-dependent bearing capacity of piles in such areas. This paper adopts the secondary development of Python to ABAQUS and employs a continuous coupling analysis method to establish a numerical model capable of simultaneously solving the large deformation of pile driving and non-Darcy flow. The model addresses issues such as mesh distortion during pile driving and the numerical implementation of three-dimensional non-Darcy flow. The accuracy of the model was verified through comparison with two experimental cases. Subsequently, the study analyzed how non-Darcy flow affects soil consolidation around the pile and the time-dependent bearing capacity of pile. Results indicate that when the permeability coefficient of the soil around the pile is less than 1 × 10−7 m/s, non-Darcy flow significantly delays the consolidation of soil within three times the pile diameter around the pile, thereby reducing the time-dependent bearing capacity of pile, with a greater impact observed for lower permeability coefficients of the soil. Once the soil around the pile reaches 90% consolidation, subsequent construction can proceed to shorten the project duration while maintaining safety.

Analisis Perbandingan Efesiensi Biaya dan Waktu pada Pondasi Sumuran dan Pondasi Tapak Pembangunan Gedung Tipikor Polda Aceh

The foundation is a building structure located under the building. The foundation cannot be separated from the building structure because it is a structural part whose function is to transmit the load from the upper structure to the supporting soil layer beneath it to prevent collapse of the soil or settlement of the structural system. This research compares the costs and time required for pit foundation work with site foundations, with the aim of finding out whether the planned costs and implementation time have the same efficiency or not. The purpose of this research is to find out how much bearing capacity there is in the well and site foundations, how much costs are needed to plan the well and site foundations, and how long the implementation time is required. The method used in this research is a comparative study (Comparison). The comparative or comparison method is research that uses the technique of comparing an object with another object. The objects being compared, the comparative method is carried out to compare the similarities and differences of two or more facts and properties of the object being studied. From the calculation analysis, the bearing capacity of the well foundation was obtained at 1950 KN with a cost of IDR 469,046,724 and an implementation time of 78 days. Meanwhile, for the site foundation, the foundation bearing capacity was obtained at 451.11 KN at a cost of IDR 174,598,298 and a construction time of 56 days.

Numerical Modeling and Performance Evaluation of Carbon Fiber-Reinforced Polymer-Strengthened Concrete Culverts against Water-Induced Corrosion

Culverts fulfill the vital function of safely channeling water beneath railway tracks, highways, and overpasses. They serve various purposes, including facilitating drainage in areas such as watercourses, drainage zones, and regions with restricted ground-bearing capacity. Precast reinforced concrete (RC) box culverts are a popular choice because they are strong, durable, rigid, and economical. However, culverts are prone to corrosion due to exposure to a range of environmental factors and aggressive chemicals. Therefore, enhancing the design and construction of this crucial infrastructure is imperative to effectively combat corrosion and to adhere to modern standards of reliability and affordability. In this study, carbon fiber-reinforced polymer (CFRP) was used to strengthen corroded culverts, with promising potential to improve safety and longevity in these structures. This study compared the behavior of corroded RC box culverts to CFRP-strengthened ones using the finite element method (FEM). It explored the impact of varying the damage thicknesses owing to corrosion, ranging from 0 mm to 20 mm, on the structural performance of the box culverts. The results showed that the CFRP model exhibited a substantial 25% increase in the capacity and reduced the damage compared to the reference model. Moreover, a parametric study was conducted for establishing a cost-effective design, in which numerous CFRP strip configurations were examined for a damaged-culvert model. The results indicated that a complete CFRP sheet was most effective for the maximum design capacity and repair effectiveness. The study’s outcomes provide valuable insights for professionals engaged in enhancing the strength of box culverts, aiming to increase the capacity, enhance the stability, and strengthen corroded culverts.

Analysis Of Bearing Capacity Of Pile Foundations Using Analytical Method And Finite Element Method

The foundation is the lower part of a structure used as a load distributor for loads generated. The selection of foundation types in building construction must consider the type and characteristics of the soil at the construction site to avoid construction failures. This analysis is conducted to determine the bearing capacity of pile foundations using analytical and finite element methods. The type of foundation used in this analysis is a pile foundation with a pile length of 8 meters and a pile diameter of 0.4 meters. For the analytical calculation, Standard Penetration Test (SPT) data obtained from PT. Adhi Karya (Persero) for the Infrastructure Green House Biodiversity LIPI Cibinong-Bogor project are used, employing the analytical method (Alpha Method) and the finite element method with the assistance of Plaxis 2D V.8 software. The results of the analysis show that the bearing capacity of the group pile foundation (Qg) for a pile diameter of 0.4 meters and a pile length of 8 meters on clayey soil, based on SPT data using the analytical method (Alpha Method), is 60.432 tons. Meanwhile, the bearing capacity of the horizontal pile foundation using the Broms method is 6.03 tons. The bearing capacity obtained using the Finite Element Method yields an ultimate load on the group pile (Qq) of 57.89 tons. The bearing capacity of the group pile foundation (Qg) from both sets of data, with a difference of 2.5%, meets the requirement, being greater than the axial load (P) of 42.6 tons that must be supported.

Method for Determining Foundation Bearing Capacity Based on Pressuremeter Test Curve

The pressuremeter test is a horizontal in-situ load test that can objectively reflect the lateral strength and deformation characteristics of the tested soil. The existing methods for determining the characteristic values of foundation bearing capacity through pressuremeter tests are mainly based on the pressure values corresponding to the starting and ending points of the straight line part of the lateral pressure load deformation curve, which has significant uncertainty. Based on the characteristics of the p-s curve, this article uses a cubic polynomial to fit the p-s curve, and the goodness of fit is greater than 0.99; gives a method for determining the characteristic values of foundation bearing capacity based on the pressure value at the inflection point of the p-s curve; and obtains the bearing capacity of the silty clay layer and the fine sand layer  in the depth range of 46.0 meters. The calculation results show that compared with the near line method, the relative error of the bearing capacity characteristics of the foundation is within 20%, which can meet the engineering needs. This provides a new approach for determining the bearing capacity of foundations through lateral pressure tests.

Integrated machine learning for modeling bearing capacity of shallow foundations

Analyzing the stability of footings is a significant step in civil/geotechnical engineering projects. In this work, two novel predictive tools are suggested based on an artificial neural network (ANN) to analyze the bearing capacity of a footing installed on a two-layered soil mass. To this end, backtracking search algorithm (BSA) and equilibrium optimizer (EO) are employed to train the ANN for approximating the stability value (SV) of the system. After executing a set of finite element analyses, the settlement values lower/higher than 5 cm are considered to indicate the stability/failure of the system. The results demonstrated the efficiency of these algorithms in fulfilling the assigned task. In detail, the training error of the ANN (in terms of root mean square error—RMSE)) dropped from 0.3585 to 0.3165 (11.72%) and 0.2959 (17.46%) by applying the BSA and EO, respectively. Moreover, the prediction accuracy of the ANN climbed from 93.7 to 94.3% and 94.1% (in terms of area under the receiving operating characteristics curve—AUROC). A comparison between the elite complexities of these algorithms showed that the EO enjoys a larger accuracy, while BSA is a more time-effective optimizer. Lastly, an explicit mathematical formula is derived from the EO-ANN model to be conveniently used in predicting the SV.

Bearing capacity of perforated surface foundations on sand

ABSTRACT Perforated foundations find widespread use in supporting offshore structures. However, there is a limited exploration of the bearing capacity of both single and multiple perforated foundations under combined loading. The finite element method is used to calculate the effect of perforations on the bearing capacity of strip surface foundations on sand subjected to combined loading in this study. The normalized bearing capacity ratio and yield surface are used to present the variation of bearing capacity, and the variation is explained by the relevant failure mechanism. The outcome indicates that the critical perforation ratio is around 0.07, and the value depends on the perforation number and loading conditions. When the perforation ratio is less than the critical perforation ratio, the combined bearing capacity of the perforated foundation will not be reduced. The bearing capacity decreases with the perforation ratio, where the number and ratio of perforation determine the decline rate and the shapes of the yield surface.

The Experimental Analysis Of The Effect Of Geotextile Reinforcement Of Cohesive Soil On The Settlement And Bearing Capacity

The properties of the soils in terms of engineering must be identified for the design of buildings and foundations to be constructed in areas where soft clay or loose sand ground conditions predominate. The engineering properties of different soils diversify in a broad range based on the sort of the ground in addition to the terrain conditions like the degree of compaction, water content, consolidation pressure, loading, and drainage conditions. Grounds may not perpetually hold the desired properties. Thanks to the structures to be built on the grounds, excessive settlements or collapses can happen because of inadequate ground bearing capacity. In order to reinforce the weaknesses of the soils, either the application of a deep foundation should be employed, or a proper improvement method should be applied to the foundation ground.In the study, the effect of the reinforcement of the geotextile, which has become widespread, on the clay ground was examined. Experiments have been conducted to identify the index properties, settlement, and sliding resistance parameters of soils on Süleyman Demirel University Soil Mechanics Laboratory on clay samples from the provinces of İzmir and İstanbul. Following the identification of the settlement and sliding values, the geotextile was added, and its effect on the settlement and bearing strength values was analyzed. Experiments were conducted by placing single-layered and double-layered geotextile in the samples with the values of optimum water content, the water content 10% more than the optimum value, and the water content 10% less than the optimum value.The results achieved after laboratory experiments are displayed with graphics and compared with each other.

METHODS OF INJECTION STRENGTHENING OF FOUNDATIONS IN CONSTRUCTION

The article discusses the problems of strengthening strip foundations of buildings and structures. In accordance with the main reasons for strengthening foundations and artificially improving the construction properties of the soil foundation, the reserves and reserves of the bearing capacity of the soil foundation were assessed by analyzing the results of the technical condition of the building and analyzing its physical condition and mechanical characteristics. The exact dimensions of the foundation structures, their condition and the loads acting on them were determined, and the geological and hydrogeological conditions of the surrounding area were studied. A classification of methods for strengthening foundations and artificially improving the construction properties of the soil foundation is given; it is proven that strengthening methods depend on the design features of the building, types of foundations, operating loads, engineering-geological and hydrogeological conditions. In addition to the need to strengthen, as well as the capabilities and technical equipment of organizations performing this type of work, there are many other methods. Pile reinforcement methods are one of the most effective types of foundations. Research has proven that piles are not used to strengthen foundations, since the resulting dynamic impacts can lead to additional settlement of the building being restored. The study noted the basic requirements for reliable strengthening of the foundation and artificial improvement of the construction properties of the soil foundation, especially when water-saturated salty clay soils are formed at the base of the building.

Serviceability of railway slab track foundations with retaining walls under train loading

ABSTRACT Railway retaining wall designs tend to disregard vehicle-induced trackbed deformation control, despite its potential impact on infrastructure serviceability. To fill this gap, this study seeks to develop an improved method to assess the performance of railway gravity retaining walls, specifically focusing on managing slab trackbed deformation. Utilizing a validated 3D numerical model, the research examines the impact of five parameters – wall width, location, inclination, embankment height, and ground-bearing capacity – on trackbed surface displacement (ω) arising from train loading. The multivariate adaptive regression splines (MARS) approach is applied to establish the mathematical relationship between these factors and an assessment indicator for evaluating track foundation serviceability. This indicator is the trackbed surface displacement index (R ω ), signifying the ratio of the maximum allowable to the practical ω value. Results highlight the necessity for comprehensive retaining wall design to ensure R ω ≥1.0, particularly when the wall is near the track, steeply inclined, or supporting a tall embankment.

Effect of urbanization on groundwater resources hydrodynamics and bearing capacity: a case study from the Bayraklı region, İzmir, Türkiye

The bearing capacity of soil is a critical factor in the design of foundations for civil engineering structures. The bearing capacity depends on soil properties, as well as the location of the water table. A rise in the groundwater level can be dramatic, especially in highly urbanized regions, and can affect the bearing capacity of foundations. In this study, groundwater-level fluctuations in a highly urbanized region in İzmir, the third largest city in Türkiye, was monitored over a 1 year period, and its effect on reducing the bearing capacity, which is not considered in foundation design and construction, was investigated. For this purpose, four observation wells equipped with groundwater data loggers were used to determine the variations in groundwater level over 1 year. Using the Terzaghi approach to calculate the bearing capacity, normalized bearing capacity plots for various foundation width/depth ( B / D f ) ratios were generated for all four observation wells. Remarkable bearing capacity changes of 10.94, 8.21, 7.62 and 9.29% were observed in four different observation wells (OW-1, OW-3, OW-6 and OW-9, respectively). The study showed that changes in groundwater level in the region caused by urbanization poses a potential risk to the sustainability of previously constructed foundations.

Behavior of soil reinforced with micropiles

Abstract Soil investigation is very important to check the bearing capacity before constructing any structure. There are different types of soils that cause many problems for the structure in short and long term, which are known as problematic soils. A lot of researchers dealt with improvement and reinforcement of the problematic soils by physical and chemical treatments. The objective of this study is reinforcing the problematic soil with micropiles with different depths and different configurations. In this study, two types of soils, soft clay and loose sand, were used to study the effect of adding micropiles of different depths and different configurations to investigate the best improvement of bearing capacity for shallow foundations on these soils. The results showed that reinforcing the natural soil with micropiles could improve the pressure carrying capacity of the problematic soils. When the design width is changed from under foundation alone to under foundation and 2B width, the soil reinforced with 2B depth of micropiles can raise the soil’s load carrying capacity by 45 to 65% when compared to untreated soil. Just 7% more bearing capacity may be achieved by increasing the depth of the micropiles from 2B to 3B (where B is the footing width); as a result, going deeper than 2B is not advantageous. Additionally, the bearing capacity of the micropiles increases by only 3% when the breadth of the configuration is increased from 1B to 2B; so, wider configurations than 1B are invalid.

Stress and deformation characteristics of ultra-long bored pile in deep soft soil area

In view of the diverse geological conditions in China, ultra-long bored pile can effectively enhance the bearing capacity and stability of foundation. Due to the special geological condition in the Beijing-Tianjin-Hebei region, there are a large number of soft soil areas. Taking an elevated bridge in Xiongan-Daxing track construction project as an example, this paper uses finite difference method to study pile-soil interaction and failure mode of pile. With the increase of load, plastic failure occurs first at the top of the pile and then at the bottom of the pile. At the same time, the curve of the plastic failure zone of the soil layer presents a process of “gentle - rapid - gentle - steep rise”. When the load reaches a certain critical value, the plastic zone area changes abruptly. As the load increases, the funnel-like characteristics of the maximum and minimum principal stresses diminish, resulting in minimal stress difference throughout the soil layer.

Influence of Soil Excavation on Bearing Behavior of Pile Group Foundation Composed of Underpinning Piles and Existing Piles

Abstract The behavior of underpinning piles during the soil excavation is critical for constructing new basements under the existing structures in urban areas; however, none of the existing studies has systematically evaluated their performance and interaction with existing piles under loading. This study aims to experimentally evaluate the impact of soil excavation on the bearing capacity of pile group foundation composed of underpinning piles and existing piles under loading. A model pile foundation with four model piles, one pile cap, and retaining structures was first constructed in our laboratory. Different soil excavation depths at 10 cm, 20 cm, and 30 cm (soil type: clayey silt) were used to explore their influence on the pile side friction, the axial force of the pile shaft, and pile settlement. The results were compared with the bearing behavior of the pile group foundation composed of four model piles and five underpinning piles at different pile lengths (500, 600, and 700 mm) and diameters (5, 10, and 15 mm). The results showed that soil excavation activity could immediately activate the different interaction responses between piles and soils and cause foundation settlements. The underpinning piles with sufficient length (more than 67 % of the existing model pile length) and diameter (more than 25 % of the existing model pile diameter) as well as proper pile’s embedded depth significantly reduced the foundation settlement, particularly at high soil exaction depth. The pile-soil interaction mechanism caused by soil excavation is revealed. The work could bring insights to the underpinning pile design for basement excavation beneath existing buildings.

The decrease of the bearing capacity of single pile foundation during earthquake on liquefiable soil (Study Case: Birobuli Area, South Palu)

Birobuli is located South Palu, Indonesia. In Indonesia, earthquakes are frequent events. Consequently, it is crucial to consider the safety of building structures against earthquakes when calculating the factor of safety of the building. It is important to not only analyse the impact of earthquakes on the superstructure but also take into account their effect on the substructure. One potential substructure failure caused by earthquakes is soil liquefaction, which refers to a decrease in soil bearing capacity resulting from seismic activity. To assess this phenomenon, a quantitative approach was employed in this study, involving soil investigations and sampling from the field. The findings from the soil investigation were used to calculate the susceptibility of soil liquefaction in different soil layers and the axial bearing capacity of single pile foundations both before and during earthquake and liquefaction. The study site predominantly consisted of silty sand with ground water table (GWT) level at -4m with low CPT value, making it susceptible to liquefaction from depths ranging between -4 meters and -12 meters. Two single pile models were simulated in the study, with respective reductions in their axial pile bearing capacity of 71,6% and 38,9%

Digital solutions in the determination of bearing capacity for straight and stepped mat foundations on sloping ground

On sloped sites where a mat foundation is to be used, because of the limited bearing capacity of the ground, it is necessary to cut into the sloped surface to provide a level base for the mat foundation. To reduce the amount of excavation and backfill a stepped mat may be used down the slope. Traditionally, determining the bearing capacity values for spread foundations on sloping ground has been a complex and time-consuming process. Several factors must be considered, including various variables (soil type, soil profile, slope angle and geometrical configuration of the infrastructure). The digital solution used in this study involves the use of advanced software that takes into account various input parameters and performs complex calculations to determine the bearing capacity of the foundation on horizontal and sloped ground. For this research, the analyses were done for three different slope angles (β = 5°, 10°, 15°) and a comparison is made between the bearing capacity of the ground for straight and stepped mat foundations using both analytical methods and finite element method.

Bearing behavior of pile foundation in karst region: Physical model test and finite element analysis

Abstract The presence of karst formations significantly impacts the load-bearing capacity of pile foundations in karst geological environments, posing a challenge to their design. This study investigated the bearing characteristics of karst pile foundations using the physical model test and numerical analysis. First, the influence of cave height and span on the bearing capacity of pile foundations is examined using model tests. The results demonstrate that the height of karst caves greatly affects the bearing capacity of karst pile foundations. Subsequently, numerical analysis further explores the bearing characteristics of these foundations. It reveals that as the top load on pile increases, an arch-shaped tensile damage zone forms at the top of karst cave and gradually expands. The rock failure in this area leads to a decrease in adhesion between rock strata and pile foundation, consequently reducing its load-bearing capacity. Finally, experimental results are compared with numerical results to validate consistency and mutual verifiability between physical model tests and numerical analyses. The outcomes of the research provide valuable insights for designing rock-socketed pile foundations in similar karst areas.

Investigation on the bearing capacity evolution of building pile foundation during permafrost degradation

The warming and melting of permafrost due to climate warming pose a considerable threat to the integrity of the Pan Arctic building, thus jeopardizing sustainable development. The increase in ambient temperature in permafrost areas will cause deterioration in the bearing capacity of building pile foundations. Considering the continuous deepening of the active layer (za), the present paper used small-scale physical modeling to investigate the potential variation of bearing capacity and load transfer mechanism of pile foundations under the scenario of continuous degradation of permafrost. The ultimate bearing capacity of a single pile and the undrained shear strength of the ground under different za are estimated by cone penetration tests. In the static load test of single piles, the axial load-settlement, axial force of pile shaft, and earth pressure at the pile tip are measured. The results show that the rise in ground temperature and the deepening of the za shorten the elastic and elastic-plastic stages of the load-displacement curve, resulting in a gradual decline in the bearing capacity of a single pile. The pile-soil interface temperature is always higher than the adjacent ground temperature at the same depth. Adfreezing force of the pile-soil interface decreases due to the increase in ground temperature and water content. With the deepening of za, the peak point of the shaft resistance decreases from −30 cm to −60 cm under the ultimate state. Meanwhile, with more axial load transfer along the pile shaft to the pile tip, the share ratio of pile tip resistance to ultimate stress gradually increases. In addition, the temperature rise of frozen soil at the pile tip accelerates the settling rate of the pile, which eventually causes the pile foundation failure.

Design of Conical Foundations with Increased Bearing Capacity in Areas of Undermined Soils

This article discusses the foundations of a conical shape directed with their apex downwards to increase the cross-sectional area and, accordingly, the bearing capacity during settlement and under the influence of horizontal tensile strains in undermined areas. To simulate the deformability of undermined and seismically exposed foundations, a three-dimensional expandable box was manufactured and assembled. Models of a conical foundation with an aperture angle of the cones at 90° and 80° were buried into the soil at 0.75 of its height, in order to provide a safety margin for further loading due to an increase in the bearing area when the cone is immersed deeper into the ground. Laboratory and field tests were performed on the vertical loading of single cones before and after horizontal soil displacement. Numerical modeling of the interaction between soil and foundation was carried out for conical foundation models that were considered for laboratory and field testing using the Plaxis 2D (Version 8.2) program. To compare the bearing capacity, isolated shallow foundations with a diameter equal to the cross section of the conical foundation at the intersection with the ground surface were tested. The isolated shallow foundations lost their bearing capacity after 0.15 kN in laboratory tests and after 75 kN in the field tests, while the ultimate bearing capacity of conical foundations with the similar cross section at the soil surface was not achieved, even after 0.2 kN during laboratory tests with horizontal soil displacement and at a load of 100 kN in field tests.

Study on the Influence of Water Erosion on the Bearing Capacity and Function of the High Pile Foundation of the Wharf

High-pile foundation is a common form of deep foundation commonly used in ocean environments, such as docks and bridge sites. Aiming at the problem of bearing capacity of high pile foundations, this paper proposes the calculation of bearing capacity and the analysis of scour depth of high pile foundations under the action of scour based on the modified p-y curve. In this paper, three kinds of scour mechanisms—natural evolution scour, general scour, and local scour—are described; and the calculation methods of scour widely used at present are compared and analyzed. The solution of the vertical stress of soil around the pile under local scour is solved and applied to the β method to solve the lateral resistance of the pile under local scour. The local erosion is equivalent to the whole erosion, and the expression of the ultimate soil resistance before and after the equivalent is calculated, respectively, according to the principle that the ultimate soil resistance at a certain point above the equivalent pile end remains unchanged. The distance from the equivalent soil surface to the pile end can be obtained simultaneously, and then the equivalent erosion depth, p-y curve of sand at different depths, and high pile bearing capacity can be obtained. Finally, it is found that the bending moment of a single pile body varies along the pile body in the form of a parabola, and the maximum bending moment of the pile body is below the mud surface and increases with the increase in horizontal load. When the scouring depth is 30 m, the horizontal load is 25 KN, and the maximum bending moment of the pile body is about 150 N·m. The data with a relative error greater than 10% accounted for only 16.6% of the total data, and the error between the calculated value and the measured value was small. The formula can predict the erosion depth more accurately.