Bearing Capacity Of Foundation Research Articles

The Horizontal Bearing Characteristics and Microscopic Soil Deformation Mechanism of Pile-Bucket Composite Foundation in Sand

The pile-bucket composite foundation represents an innovative foundation form that surpasses the horizontal bearing performance of both single bucket-shaped foundations and pile foundations. The intricate interplay between piles and buckets introduces the complexity of the factors influencing the bearing performance of composite foundations under horizontal loads. In this paper, the indoor model tests were conducted to investigate the effects of relative density and pile-to-barrel diameter ratio on the horizontal bearing capacity and surrounding soil pressure of the pile-bucket composite foundation. A sensitivity analysis on the bearing characteristics of the pile-bucket foundation was performed using ABAQUS/CAE 2020 software. The results reveal a consistent variation in load–displacement curves across diverse diameter ratios of piles to buckets. The pile-bucket diameter ratio significantly impacts the horizontal bearing characteristics of the composite foundation. Reducing the pile-bucket diameter ratio improves the horizontal bearing capacity of the composite foundation. When the diameter ratio of piles to buckets diminishes to ≤0.317, the influence of this ratio on bearing performance becomes markedly pronounced. The displacement range of the surface soil decreases with an increase in relative density, while the influence depth of the surrounding soil of the composite foundation significantly decreases as the pile-to-barrel diameter ratio decreases.

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.

Combined bearing capacity of footings on geogrid-reinforced granular fill over soft clay

The current study investigates the ultimate bearing capacity of obliquely/eccentrically loaded shallow strip foundations resting on a geogrid-reinforced granular fill with limited thickness over a very soft to soft clay layer. To this end, the lower bound theorems of the finite element limit analysis (FELA) and second-order cone programming (SOCP) are effectively exploited to simulate the underlying clay deposit, geogrid layer, and granular fill along with the inclined/eccentric loading exerted on the overlying footing. The accuracy of the adopted formulations is rigorously examined through several comparisons with the results of a well-established analytical approach in the literature. A comprehensive parametric study is then conducted to properly examine the influences of the geosynthetic layer characteristics and soft clay properties on the overall bearing capacity and failure envelope of the strip footing subjected to wide ranges of inclined and eccentric loadings. The results show that placement of a geogrid-reinforced granular fill layer over the soft clayey soil significantly increases the bearing capacity of the shallow foundation. The ultimate tensile strength of the reinforcement layer and the cohesion of the underlying very soft to soft clay deposit are also observed to have considerable effects on the size of failure envelopes.

Experimental and numerical studies on lateral bearing characteristics of innovative gravel-filled canister-monopile (GCM) hybrid foundation

In recent years, the monopile foundation is increasingly utilized to support offshore wind turbines (OWT). However, as the OWT becomes larger, a larger monopile diameter is always required to resist lateral loads, resulting in an increase in the construction cost and installation effort of the monopile. Therefore, an innovative gravel-filled canister-monopile (GCM) hybrid foundation is proposed to provide greater lateral bearing capacity of monopile without raising construction cost and minimizing installation effort. The hybrid foundation that integrates an additional canister filled with gravel alongside the monopile, can increase the horizontal bending stiffness and improve soil resistance as the soil beneath the canister. To evaluate the lateral bearing capacity of the GCM hybrid foundation and compare it with the conventional monopile, the model tests as well as the finite element analysis are conducted in this regard. The results show that the hybrid foundation outperforms the monopile in terms of increasing lateral bearing capacity, moment resistance and reducing lateral deformation. Furthermore, a thorough parametric study evaluating the effects of canister dimensions, backfill properties and loading eccentricity on the lateral bearing characteristics of a hybrid foundation are evaluated. Some design suggestions are provided for the further application of the hybrid foundation in OWT projects.

Investigating stone column effectiveness for sabkha soil improvement: field tests and numerical model

This study explores the application of stone columns to improve the bearing capacity of sabkha soil for the construction of a Lattice Communication Tower foundation in the Eastern Province of Saudi Arabia. Geotechnical investigation report, an on-site footing loading test to evaluate the foundation's bearing capacity and settlement behavior following stone column installation, and post-cone penetration tests (CPT) to assess soil densification are all part of the study data. The uppermost 4 m of the soil profile comprise a medium to dense layer of sand with silt, followed by a 12-m layer of weak sabkha soil (SPT, N less than 4). Below the sabkha layer, the strata exhibit varying densities, ranging from medium to dense and very dense layers, extending to the maximum depth of investigation. The comparison of Pre- and Post-CPT data revealed significant improvements in the sand and silt layer above the sabkha layer, as well as moderate improvements in the upper portion of the sabkha layer. However, the majority of the sabkha soils and underlying soil layers did not show significant improvement. Plaxis 3D numerical models were employed to provide insights into the performance of the composite area encompassing stone columns and the surrounding soil. Comparing field tests and numerical models showed that neglecting stone column installation effects in numerical models led to overestimating settlements. However, when examining the field data and numerical results with a raised coefficient of lateral earth pressure when of K∘=2\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${K}_{^\\circ }=2$$\\end{document}, a distinct alignment between settlement values consistent with those derived from field testing. The findings highlight the importance of including site-specific conditions and installation effects in numerical modeling to accurately predict the behavior of stone columns in sabkha soils.

Analysis of Bearing Capacity and Foundation Settlement of Luan Linggi Bridge, Aceh Province, Indonesia

A bridge is a structure made to cross a ravine or obstacle such as a river, railroad, or highway. The bridge consists of an upper structure and a lower structure. The upper structure of a building must be able to be supported by its own lower structure, namely the foundation. There are two types of foundations, namely shallow foundations and deep foundations. The planning of a foundation is said to be correct if the load that is forwarded by the foundation to the ground does not exceed the strength of the soil. Luan Linggi Bridge is one of the bridges that uses deep foundations in the form of pile foundations. This bridge is located in Luan Linggi Village, East Simeulu District, Simeulue Regency, Aceh Province, Indonesia. Due to the 2004 Tsunami disaster, the bridge pillars were broken and the abutments shifted, so the bridge could no longer be used. So, the bridge was redesigned in 2015 and rebuilt in 2021. This study aims to determine the value of the bearing capacity of a single foundation, the value of the bearing capacity of the group foundation, and the foundation settlement. This research uses N-SPT data, soil physical and mechanical properties, and detailed engineering design (DED). The method used to calculate the bearing capacity of the foundation is the Luciano Decourt method, while the single foundation settlement uses the Vesic method. The results obtained from this research are the bearing capacity and settlement value of the pile foundation with a diameter of 40 cm and a depth of 22 m. The ultimate bearing capacity value of the single foundation obtained is 375,228 tons, the permit bearing capacity value of the single foundation is 125,076 tons, the bearing capacity value of the group foundation obtained is 5887,727 tons. The elastic settlement value of the foundation using the Vesic method is 2,88 cm, and the settlement value of the group foundation is 8,8 cm.

Analysis on the synergistic variation of soil freezing and pile foundation bearing capacity in permafrost regions

The construction of bored piles in permafrost regions disturbs the thermal stability of frozen soil, leading to decreased early bearing capacity of the pile foundation. As the permafrost ground temperature influences the area, the pile-soil gradually undergoes refreezing, resulting in a continuous enhancement of the pile foundation's bearing capacity. To study the synergistic variation law of soil refreezing and bearing capacity of bridge pile foundation in permafrost regions, two test piles with a length of 15 m and a diameter of 1.2 m were poured based on the actual bridge engineering construction project in the permafrost region of Daxing’an mountains, China. The intelligent temperature monitoring system was set up inside and in the area where the test pile was located. Combined with the collected temperature data, the refreezing state of pile-soil was comprehensively judged. The self-balancing method was employed to assess the bearing capacity of pile foundation before and after refreezing, unveiling the variation patterns in friction resistance at different soil layers and pile-end resistance. On this basis, a finite element model was established to analyze the interaction between pile side friction and pile tip resistance at varying depths of frozen soil. The test and analysis results revealed that the permafrost temperature in the pile foundation area was −1.9℃.Following pile-soil refreezing, the ultimate bearing capacity of the pile foundation increased by 2232 kN, and the growth rate was 42.9%. The friction resistance of each soil (rock) layer on the pile side increased, with the growth rate ranging from 15% −75%.

Field study on pile side grouting reinforcement for in-service pile foundation using segmental localized grouting

Grouting is an effective method to enhance the bearing capacity of in-service pile foundations. The effect of optimizing grouting parameters for in-service pile foundation grouting reinforcement was verified through static load tests. The field tests of the pileless stratum show that the cement-sodium silicate slurry is more favourable for increasing the grouting pressure and more convenient to control the slurry diffusion than cement slurry. The grouting parameters of cement-sodium silicate slurry were determined according to the maximum grouting pressure and quantity. The slurry grouting parameters were cement slurry 1.6g/cm3 and cement slurry to sodium silicate ratio 2.29:1. Moreover, the effective range of segmental localized grouting reinforcement was detected by the resistivity method and in-situ standard penetration test, and the grouting position should be less than 2m from the side of the in-service pile foundation. Finally, it is found that pile side grouting can improve the bearing capacity of in-service pile foundation by 98% through static load test. The research results have reference value and guiding significance for the design and effect detection of pile foundation grouting reinforcement.

The Effect of Lateral Confinement on The Ultimate Bearing Capacity of Shallow Foundations on Sand

The Effect of Lateral Confinement on The Ultimate Bearing Capacity of Shallow Foundations on Sand

Using shear modulus to predict the bearing capacity of strip foundations on sand

This paper reports results of a study to predict load-settlement behaviour of strip foundations on a dry uncemented sand using only soil stiffness data, under both working loads and extreme loads. This involved predicting the strength of a foundation system without using any strength parameters. A non-linear stepwise load-settlement prediction algorithm was utilised, which used the small-strain shear modulus of layers below the footing, a suitable stiffness modulus reduction curve and elasticity theory. The algorithm was adapted to predict the ultimate bearing capacity, as well as to construct astress-settlement curve and determine the bearing pressure experienced beneath a foundation at any particular settlement. The method was evaluated using two different sets of modulus reduction curves, for small-scale model foundations on loose, medium dense and dense sand. Model tests were conducted at 1g. Particle Image Velocimetry (PIV) was used to observe strains within the soil during loading. These strains were used to calculate the shear modulus of discrete layers throughout loading and back-estimate the layer small-strain shear moduli. Additionally, the mode of shear failure for each test at ultimate bearing capacity was observed using PIV. Modulus reduction curves that initially degrade shear modulus rapidly beyond the elastic threshold strain (0.001%) gave superior predictions under the given conditions. Using such curves, ultimate bearing capacity predictions produced errors of 0.4% to 10.8%. Using the same input parameters, stresssettlement predictions were of satisfactory accuracy over the entire settlement range.

Simulation of the ultimate bearing capacity of a spread foundation on sandy soils: rigid plastic FEM approach with inclined load and size effect incorporating stress-dependent non-linear yield function

Simulation of the ultimate bearing capacity of a spread foundation on sandy soils: rigid plastic FEM approach with inclined load and size effect incorporating stress-dependent non-linear yield function

Studying the Behavior of Expansive Soil Reinforced by Micropiles

Expansive soil is a form of soil that can expand and contract, changing its volume. Montmorillonite, a mineral with the ability to dissolve in water, makes up the majority of these kinds of soils, and by increasing the volume of the soil, it causes the soil to heave. Expansive soils could be a substantial concern for engineered buildings due to their capacity to adjust to seasonal variations by contracting or expanding moisture content. Many researchers focused on soils that were swollen and looked at how they behaved as well as how they could be improved. In this study, the work depends on inserting micro-piles with different depths and configuration widths to investigate which depth and configuration can be obtained to improve the bearing capacity of foundations on expansive soil. The main purpose of this study is to reinforce the expansive soil with micro-piles with different depths (1B, 2B, and 3B) and different configuration widths (under footing only, 1B and 2B). It was concluded that the soil reinforced with micro-piles improved the load-bearing capacity of the expensive soil and decreased the swell pressure. The increasing depth of the micropiles 2B to 3B (B is the width/diameter of the foundation) can increase the bearing capacity by just 6%; therefore, increasing the depth beyond 2B is not beneficial. Also, the increase in width of the configuration of the micro piles from 1B to 2B increases the bearing capacity by just 4%; therefore, the increase in width greater than 1B is not valid. Doi: 10.28991/CEJ-2024-010-01-017 Full Text: PDF

Evaluation of Empirical Formulas to Estimate Axial Capacity of Bored Pile in West Java, Indonesia

Pile foundation is part of the substructure that plays an important role in carrying and supporting the load acting on it. Therefore, a proper foundation design by estimating the bearing capacity of pile foundation is needed to ensure the safety of the building foundation. To achieve better estimation of pile capacity, analysis of the axial bearing capacity should be verified by pile test results such as Static Loading Test or dynamic test with a Pile Driving Analyzer. Based on the pile test data, the values of the skin friction and end bearing resistance can be back calculated, and hence it can be used in the calculation of pile bearing capacity using empirical methods. In this study, bearing capacity analysis was performed for drilled pile foundations, which had been tested using Static Loading Test and Pile Driving Analyzer. The analysis was carried out by comparing the results of empirical calculations for each test pile with the results of field tests. The calculation results were then compared to the empirical adhesion factor (alpha) method, which is commonly used by practicing engineers in Indonesia, according to the methods proposed by Kulhawy (1984), Reese & Wright (1977), and Reese & O'Neil (1988). Based on the 104 test piles data, the results are more in good agreement with the adhesion factor proposed by Kulhawy (1984) with a correlation of undrained shear strength, cu of 8 NSPT, a correlation of unit skin friction for sandy soils of 2.2 NSPT, and a correlation of unit end bearing for sandy soils of 70 NSPT-ave.

Bearing capacity factor for strip foundations on unsaturated clay

ABSTRACT The matric suction in unsaturated soil depends on the type of soil and various flux conditions i.e., infiltration, evaporation and no flow. The shear strength of unsaturated soil changes with change in matric suction leading to varying resistance of soil under various flow conditions. In this study, the bearing capacity of strip foundations resting over unsaturated clay considering variation of matric suction with depth for different surface flux conditions and position of water table, has been obtained using finite element lower bound limit analysis. Modified Mohr-Coulomb yield criteria based on unified effective stress approach has been employed to incorporate the contribution of matric suction stress to the failure condition. A non-dimensional bearing capacity factor was introduced to estimate the bearing capacity of strip foundations and presented as a function of different influencing parameters such as foundation width, water table depth, soil properties, various flow conditions and their flow rate, and surcharge pressure. The influence of variation of unit weight of soil in the unsaturated zone, air entry and pore size distribution parameters, residual degree of saturation of soil, specific gravity of soil solids, and foundation-soil interface roughness on the bearing capacity has also been examined and found to be insignificant.

Numerical study on undrained multi-directional bearing capacity of hybrid subsea foundation

The traditional foundation design does not consider the bearing capacity under multi-directional coupling load. However, the foundation is usually subjected to vertical (V), horizontal (H) and moment (M) loading simultaneously on the seabed. The present study examines the undrained multi-directional bearing capacity of hybrid subsea foundation in saturated soft clay using finite element analysis. The contribution of the mudmat and the suction bucket to the bearing capacity of the hybrid subsea foundation was evaluated. The results show that the suction bucket can effectively make up for the lack of horizontal anti-slip and anti-overturning ability of the mudmat. It has a significant contribution to the horizontal and moment bearing capacity. In addition, the failure envelope of bearing capacity in horizontal-moment (H-M), vertical-horizontal (V-H), and vertical-moment (V-M) load space is obtained by using prescribed displacement ratio loading method. Based on the simulation results, the expression of approximate envelope of foundation bearing capacity under combined load of horizontal and moment is proposed. The study also found that a certain value of vertical load can increase the horizontal and moment bearing capacity of the hybrid subsea foundation, while excessive vertical load will lead to a decrease in bearing capacity.

Investigating the influence of root layer quantity on the pullout bearing characteristics of root piles in coral sand foundations

Root piles with good load-bearing characteristics can be used as foundations for offshore wind power facilities. By conducting model tests on root piles with varying numbers of root layers in coral sand foundations and studying the theoretical pullout ultimate bearing capacity, the influence of the number of root layers on the pullout bearing characteristics of root piles is analyzed. Subsequently, a formula for calculating the pullout ultimate bearing capacity of root piles is derived, drawing on the Vesic foundation bearing capacity theory and the Rankine soil pressure theory. The results indicate that increasing the number of root layers enhances the ultimate bearing capacity of root piles, enabling them to better withstand pullout forces and control displacement. The axial force curve of the roots exhibits a step-like pattern. Additionally, the maximum lateral mechanical resistance of the root piles in 3 and 5 layers gradually shifts downwards with increased loading. While the total bearing capacity of the root section increases, the rate of increase diminishes over time. Model test data validates the proposed theoretical formula for calculating bearing capacity, affirming its reliability. These research findings furnish a theoretical groundwork for the practical application of root piles in engineering.

Vertical behavior of a suction caisson using state-dependent sand friction angles

The vertical bearing capacity of the suction caissons is vital to the safety of marine jacket foundations. The sand friction angle is a key parameter for calculating the vertical bearing capacity. The sand friction angle is state-dependent, which is affected by the compact state and stress state. However, this effect is neglected in the current study, resulting in deviations in the calculation results of the vertical bearing capacity. Therefore, a novel method is preliminarily proposed to account for this impact while evaluating the vertical bearing capacity of suction foundations. First, a new friction angle is expressed as a function of relative density and soil depth, which differs significantly from the commonly used constant friction angle. The state-dependent sand friction angle is available. Then, the general and simplified vertical bearing capacity formulas are clarified. Four key parameters in the former and a new first-order coefficient in the latter are identified. The calculation procedure based on the new friction angle is also specified. Finally, combined with model tests, a comparison study is carried out. The results show that the calculation results using the new friction angle are more accurate and practical. This study can provide a reference for the foundation design.

Analytical analysis of cylindrical cavity expansion considering particle breakage effect of sand and its application for cone penetration tests

AbstractThe particle breakage effect in sand exerts a significant influence on the design of underground space structure. However, the existing theories seldom consider the breakage effect and often lack accurate descriptions of void ratio changes, leading to substantial errors in the numerical calculations compared to the actual scenario. This study employs the simple critical state sand model (SIMSAND) to account for the particle breakage effect and transforms the drained cylindrical cavity expansion problem into a set of first‐order ordinary differential equations described by the Lagrangian method. The analytical solution of the cylindrical cavity expansion problem is calculated using Matlab programming codes. Firstly, Fontainebleau sand is investigated to analyse the influence of initial stress, void ratio and specific volume around the cavity. The combined effects of initial stress and particle breakage on the soil around the cavities result in dilatancy characteristics and a reduction in void ratio. The stress path analysis reveals that the soil around the cavities only reaches a critical state under high initial stresses. Secondly, a plane strain numerical model is established for twice expansion to verify the calculation outcomes from the cylindrical cavity expansion theory. Finally, an axisymmetric cone penetration test (CPT) model is developed to analyse the theoretical and numerical solutions for expansion stress and sleeve friction. The research results indicate that the CPT in sand need to consider the particle breakage effect, especially under high stress conditions. Without considering particle breakage, the sleeve friction is overestimated. These research findings can offer guidance for geotechnical engineering applications, such as CPT, pressuremeter tests and predictions of bearing capacity for pile foundations in sand.

The Application of Soft Foundation Treatment of Cement-soil Mixing Pile in Zhangzhuang Pumping Station

The text introduces the process of comparison and selection of foundation treatment scheme, combining with example of foundation treatment in Zhangzhuang pumping station, and elaborates the detailed design steps and calculation way of cement-soil mixing pile,the economy benefits is very significant through settlement check, composite static load test, static load test of single pile, the bearing capacity of composite foundation meets the design demand.

Investigating the bearing performance of the foundation under the combined effects of flood scouring and soaking

Bearing capacity degradation of foundations under the impact of the flood is one of the major reasons responsible for the collapse and damage to the rural buildings, posing a serious threat to the local village societies. Based on a case study of a rural building foundation had been destroyed by flooding. This paper investigated the deterioration process of rural building foundations under the combined effect of dynamic scouring and static soaking caused by flooding. Using the two-dimensional shallow water equation, erosion depth was calculated for different flood velocities. Then, the bearing capacity degradation under the combined scouring-soaking effect was analyzed using the finite element method. Finally, investigating the influence of inflow direction and building group masking on the foundation's bearing capacity. The results indicate that under the combined effect, the bearing capacity of village building foundations decreases by 47.88%, with scouring slightly more impactful than soaking. Inflow angle has minimal effect on bearing performance, while the masking effect of the building group provides better protection for the foundation of rear buildings.