Study of soil disturbance effect on bearing capacity of helical pile by experimental modelling in FCV

Fateh, Amir; Eslami, Abolfazl; Fahimifar, Ahmad

doi:10.1080/19386362.2016.1222692

Cited by 16 publications

(4 citation statements)

References 10 publications

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“…As illustrated in Fig. 2, these sensors were used in two directions, vertical and horizontal to measure soil vertical and horizontal pressure, respectively [24,30,34]. It can be interpreted from the figure that the horizontal and vertical stresses change approximately with depth in a linear manner [31,35].…”

Section: Cpt In Physical Modelingmentioning

confidence: 99%

Effect of Cone Diameter on Determination of Penetration Resistance Using a FCV

et al. 2021

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The cone penetration test (CPT) and dynamic cone penetration test (DCPT) are the most two efficient in-situ tests in geotechnical practice. Due to experimental test limitations, it is sometimes impossible to use cone penetrometer (CP) with standard dimensions via physical modeling, and the use of smaller size of CP is needed. The objective of this study has been to investigate the size effect of CPT on penetration resistance. The sand material collected from a coastal area of the Caspian Sea in Babolsar city. Frustum confining vessel (FCV) was used due to its ability in high stress physical modeling and forming approximately linear distributed stress in depth, which makes it one of the most suitable physical modeling apparatus for investigating DCP and CPT. In this research, two different CPs, a standard dimension (35.7 mm) and a smaller size (24 mm in diameter), and one standard DCP were employed to be tested in Babolsar sand. Results demonstrate that the cone resistance (q c ) and sleeve friction (f s ) values are greater in the miniCP compared to the standard cone. This trend goes more notable when either of relative density or vertical effective stress increases. However, the ratio of cone resistance or sleeve friction, for MiniCPT to standard CPT is constant with various values of vertical effective stress or relative density. Accordingly, the cone resistance and sleeve friction ratio for MiniCPT in comparison to CPT are greater almost 1.23 and 1.18, respectively. Also, the correlation values between q c with sand parameters, obtained from laboratory tests, relative density (Dr), porosity (e), and with dynamic cone penetration index (DPI) have been investigated and presented.

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Section: Cpt In Physical Modelingmentioning

confidence: 99%

Effect of Cone Diameter on Determination of Penetration Resistance Using a FCV

et al. 2021

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“…Zarrabi and Eslami [22] scrutinized the construction effects on the performance of piles, using physical modeling in FCV-AUT. Askari Fateh, Eslami, and Fahimifar [23] studied the failure mechanism of three helical piles made up of hollow galvanized iron pipes with one, two, and three helices. The experimental results were verified using two static analysis methods, CFEM (2006) and Vessic (1997).…”

Section: Introductionmentioning

confidence: 99%

Axial bearing capacity of helical piles in moist and saturated conditions using frustum confining vessel (FCV)

Jassim,

Ganjian,

Eslami

2023

Numerical Methods in Civil Engineering

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Due to the increasing demand in construction and use of different types of piles on the one hand and the high cost of conducting large-scale tests on different types of piles, on the other hand, new methods have been proposed to study the behavior of different types of piles. Physical modeling provides the researcher the capability of studying model piles in the scaled environment at low costs. Among the different methods of physical modeling, the use of frustum confining vessels (FCV) has gained attraction in recent years. FCV is a cone-shaped vessel that can produce a stress distribution similar to the idealized linear stress distribution in depth. Helical piles are common types of deep foundations which were first used about 200 years ago. Helical Apiles are driven to the soil by applying a torque to the end of piles in the presence of vertical loads. Their quick and noise-free installation method, the minimal disturbance during the installation, and environmental compatibility make them popular for working in urban areas. In this research, using the finite element method, the optimal dimensions of FCV apparatus were selected, and the FCV apparatus with optimal dimensions were constructed. A total of 18 compression tests were performed on Anzali sand in different relative densities and moisture contents, using single-helix and three-helices piles. Results indicate that increasing the number of helices and relative density of soil increases the pile and sand contact and causes higher bearing capacity for helical piles. Soil saturation, on the other hand, significantly reduces the ultimate strength.

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“…The structure of soil has great influence on engineering practice. Engineering problems such as the stability of slope and foundation pit (Park and Kutter, 2015;Hu et al, 2019;Lu et al, 2021), the bearing capacity of foundation (Fateh et al, 2017), the settlement and deformation of foundation (Meng et al, 2018) are closely related to the structure of soil. In engineering practice, ignoring the influence of the structure of soil may cause serious consequences (Cheng et al, 2020).…”

Section: Introductionmentioning

confidence: 99%

A Constitutive Model of Clay Considering Structural Failure

2021

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Due to the different material composition and deposition conditions, the undisturbed clay presents different degree of structure. Because of the existence of structure, the undisturbed clay has structural yield stress. When the stress level exceeds the structural yield stress, the stress-strain relation of undisturbed clay has typical softening characteristics. To explore the constitutive relation of undisturbed soil, triaxial consolidation, and drainage tests were carried out on undisturbed and remolded soils of structural clay in Zhanjiang Formation in China, and the stress-strain relations under different confining pressures were obtained. By analyzing the structural failure process of undisturbed clay, Weibull distribution was introduced to describe the strength distribution of each point in undisturbed clay, and the structural failure coefficient of undisturbed clay was established during the loading process. Based on the elastic theory and structural failure coefficient, a constitutive model considering the structural failure of clay was proposed, and the method to determine the model parameters was given. The model was used to simulate the experimental data in this paper and the reference, and the validity of the model was verified. The results show that the model can well simulate the softening effect of structural clay during loading.

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Study of soil disturbance effect on bearing capacity of helical pile by experimental modelling in FCV

Cited by 16 publications

References 10 publications

Effect of Cone Diameter on Determination of Penetration Resistance Using a FCV

Effect of Cone Diameter on Determination of Penetration Resistance Using a FCV

Axial bearing capacity of helical piles in moist and saturated conditions using frustum confining vessel (FCV)

A Constitutive Model of Clay Considering Structural Failure

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