• Steel and Composite Structures
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• v.51 no.4
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• pp.417-440
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• 2024

Artificial neural networks (ANN) have been the focus of several studies when it comes to evaluating the pile's bearing capacity. Nonetheless, the principal drawbacks of employing this method are the sluggish rate of convergence and the constraints of ANN in locating global minima. The current work aimed to build four ANN-based prediction models enhanced with methods from the black hole algorithm (BHA), league championship algorithm (LCA), shuffled complex evolution (SCE), and symbiotic organisms search (SOS) to estimate the carrying capacity of piles in cold climates. To provide the crucial dataset required to build the model, fifty-eight concrete pile experiments were conducted. The pile geometrical properties, internal friction angle 𝛗 shaft, internal friction angle 𝛗 tip, pile length, pile area, and vertical effective stress were established as the network inputs, and the BHA, LCA, SCE, and SOS-based ANN models were set up to provide the pile bearing capacity as the output. Following a sensitivity analysis to determine the optimal BHA, LCA, SCE, and SOS parameters and a train and test procedure to determine the optimal network architecture or the number of hidden nodes, the best prediction approach was selected. The outcomes show a good agreement between the measured bearing capabilities and the pile bearing capacities forecasted by SCE-MLP. The testing dataset's respective mean square error and coefficient of determination, which are 0.91846 and 391.1539, indicate that using the SCE-MLP approach as a practical, efficient, and highly reliable technique to forecast the pile's bearing capacity is advantageous.

• Computers and Concrete
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• v.31 no.5
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• pp.443-455
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• 2023

This is a research analyses on the bearing capacity at a pile tip embedded in rock. The aim is to propose a shape coefficient for an analytical solution and to investigate the influence of the plastic flow law on the problem. For this purpose, the finite difference method is used to analyze the bearing capacity of various types and states of rock masses, assuming the Hoek & Brown failure criterion, by considering both plane strain and an axisymmetric model. Different geometrical configurations were adopted for this analysis. First, the axisymmetric numerical results were compared with those obtained from the plane strain analytical solution. Then the pile shape influence on the bearing capacity was studied. A shape factor is now proposed. Furthermore, an evaluation was done on the influence of the plastic flow law on the pile tip bearing capacity. Associative flow and non-associative flow with null dilatancy were considered, resulting in a proposed correlation. A total of 324 cases were simulated, performing a sensitivity analysis on the results and using the graphic output of vertical displacement and maximum principal stress to understand how the failure mechanism occurs in the numerical model.

• Proceedings of the Korean Geotechical Society Conference
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• 2001.03a
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• pp.355-362
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• 2001

Since micropiles were conceived in Italy in the early 1950s, which have been widely used for In-situ reinforcement, bearing pile or the concept of combination in the world-wide. The meaning of micropiles usually differs from that of a general deep foundation. Because the load capacity of it was mainly affected by skin friction. Also, it could be obtained the improvement effects of load capacity or ground's rigidity by the unitary behavior of ground and micropiles. In this study, The model tests were peformed on the dense sand where micropiles are set to the vertical direction. Strip footing was used in it. Steel bars of dia. 2 and 4㎜ were used in model tests of which the sand was attached on the surface, and the length of it was changed as 2B to 6B(where, B is width of strip footing) Through this process, the load capacity were analyzed from the test results in the relationship between load and displacement.

• Journal of Industrial Technology
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• v.17
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• pp.111-118
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• 1997

This thesis is an experimental research of investigating behavior of single pile, subjected to the vertical compression loads, using the centrifuge facility located in the geotechnical engineering laboratory in Kangwon National University. Centrifugal model experiments of model pile were carried out changing diameter of model pile, relative density of sandy ground and the gravitational level applied in the centrifuge. Thus, their effects on the load-settlement behavior and the ultimate bearing capacity of pile were investigated. Experimental results obtained from centrifuge model tests were compared with the theoretical or semi-empirical equations to analyze values of ultimate bearing capacity of model pile. When we compare the ultimate bearing capacity of experimental results with the ultimate bearing capacity of theorical results, the experimental results appear more higher in the De Beer method and Meyerhof. Expecially, Terzaghi method is very same as the experimental results normally.

• Land and Housing Review
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• v.2 no.1
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• pp.79-85
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• 2011

The bearing capacity of a soil can be improved by conventional ground improvement techniques such as stabilization and compaction methods. Recently, the use of geotextiles in improving the bearing capacity of soils has become popular because of the availability of durable and strong geosynthetic materials. In this paper, through the laboratory model tests on sandy ground reinforced by geotextiles with the strip footing under plane strain condition, the effects of bearing capacity improvement on the sandy ground and its behaviour were investigated.

• Journal of the Korean GEO-environmental Society
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• v.14 no.6
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• pp.5-11
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• 2013

Because the regulation for a noise and a vibration in our country has been being reinforced more and more, a more environment-friendly pile construction method than a current low-noise and low-vibration method was needed for the close construction in the downtown area. In this study, the characteristics of a screw concrete pile method for noise and vibration-free method was explained, and it's vertical bearing capacity was studied in the base of the static pile load test data of the screw concrete piles. Constructed by two methody; a pre-digging shoe type construction method and a toe-jetting shoe type construction method. The vertical load bearing capacity of a screw pile constructed by the former was more about 70% than that of a screw pile constructed by the latter.

• Structural Engineering and Mechanics
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• v.90 no.5
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• pp.447-458
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• 2024

This study investigated the influence of scale ratio and vertical load on the seismic performance of Puzuo joints in traditional Chinese timber structures. Three low-cyclic reversed loading tests were conducted on three scaled specimens of Bujian Puzuo in Yingxian Wooden Pagoda. This study focused on the deformation patterns and analyzed seismic performance under varying scale ratios and vertical loads. The results indicated that the slip and rotational deformations of Bujian Puzuo were the primary deformations. The scale of the specimen did not affect the layer where the maximum interlayer slip occurred, but it did decrease the proportion of slip deformation. Conversely, the reducing vertical load caused the layer with the maximum slippage and the position of the damaged Dou components to shift upward, and the proportion of slip deformation increased. When the vertical load was decreased by 3.7 times, the maximum horizontal bearing capacity under positive and negative loadings, initial stiffness, and energy dissipation of the specimen decreased by approximately 60%, 58.79%, 69.62%, and 57.93%, respectively. The horizontal bearing capacity under positive loading and energy dissipation of the specimen increased by 35.63% and 131.54%, when the specimen scale was doubled and the vertical load was increased by 15 times.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.14 no.4
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• pp.915-922
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• 1994

This paper presents a new method of soil improvement by using semi-flexible vertical reinforcing elements which shows promise for future work. Load tests were conducted on two model footings in a sand box using unreinforced sand and also by reinforcing the sand with vertical reinforcing elements. The ultimate bearing capacity for the unreinforced and reinforced sand has been compared. The effect of length, spacing, lateral extent of the reinforcement, and the initial relative density of sand in increasing the ultimate bearing capacity have been evaluated. The effect of roughness of the reinforcing elements has also been investigated. Based on the results of these model footing tests, it appears that significant improvement in the ultimate bearing capacity of loose and medium sands can be achieved by reinforcing with vertical elements.

• Geotechnical Engineering
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• v.11 no.4
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• pp.5-12
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• 1995

Although the pile Load test provides various informations to predict the bearing capacity of a pile, it has a considerable difficulty of requiring a large amount of weight to enable the test pile to be loaded sufficiently until the yielding or ultimate load is obtained. Many graphical and mathematical methods have been attempted to estimate the bearing capacity from the result of a vertical load test without loading to failure. In the previous work an analytical method to estimate the failure load using the maxi mum curvature which was based on the Southwell's theory was presented by the author. The failure load, as proposed by Crowther, should be defined as the load at which the predefined that criteria are exceeded. The allowable loads by Davisson's method and DIN 4014 were compared with the loads of piles using the maximum curvature, and this paper proposed the allowable load in which the safety factor of the maximum curvature was 2.5. As a result of study, it was reasonable to conclude that the allowable load determined by the maximum curvature method could estimate the vertical bearing capacity from the pile load test without loading to failure.

• Geomechanics and Engineering
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• v.31 no.6
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• pp.599-614
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• 2022

One of the methods of stabilizing retaining walls, embankments, and deep excavations is the implementation of plate anchors (like the Geolock wall anchor systems). Back-to-back Mechanically Stabilized Earth (BBMSE) walls are common stabilized earth structures that can be used for bridge ramps. But so far, the analysis of the interactive behavior of two back-to-back anchored walls (BBAW) by double-plates anchors (constructed closely from each other and subjected to the limited-breadth vertical loading) including interference of their failure and sliding surfaces has not been the subject of comprehensive studies. Indeed, in this compound system, the interaction of sliding wedges of these two back-to-back walls considering the shear failure wedge of the foundation, significantly impresses on the foundation bearing capacity, adjacent walls displacements and deformations, and their stability. In this study, the effect of horizontal distance between two walls (W), breadth of loading plate (B), and position of vertical loading was investigated experimentally. In addition, the comparison of using single and equivalent double-plate anchors was evaluated. The loading plate bearing capacity and displacements, and deformations of BBAW were measured and the results are presented. To evaluate the shape, form, and how the critical failure surfaces of the soil behind the walls and beneath the foundation intersect with one another, the Particle Image Velocimetry (PIV) technique was applied. The experimental tests results showed that in this composite system (two adjacent-loaded BBAW) the effective distance of walls is about W = 2.5*H (H: height of walls) and the foundation effective breadth is about B = H, concerning foundation bearing capacity, walls horizontal displacements and their deformations. For more amounts of W and B, the foundation and walls can be designed and analyzed individually. Besides, in this compound system, the foundation bearing capacity is an exponential function of the System Geometry Variable (SGV) whereas walls displacements are a quadratic function of it. Finally, as an important achievement, doubling the plates of anchors can facilitate using concrete walls, which have limitations in tolerating curvature.