scholarly journals A model for ultimate bearing capacity of piles in unsaturated soils under elevated temperatures

2020 ◽  
Vol 205 ◽  
pp. 05003
Author(s):  
Sannith Kumar Thota ◽  
Farshid Vahedifard
Keyword(s):  
Bearing Capacity ◽  
Unsaturated Soils ◽  
Elevated Temperatures ◽  
Skin Resistance ◽  
Ultimate Bearing Capacity ◽  
Temperature Dependent ◽  
Deep Foundation ◽  
Energy Applications ◽  
Temperature Dependent Model ◽  
Pile Resistance

Geo-energy applications such as energy piles can expose unsaturated, deep foundation soils to elevated temperatures. This paper presents a closed-form equation for the ultimate bearing capacity of piles in unsaturated soils subject to elevated temperatures under drained conditions. For this purpose, a temperature-dependent effective stress model was incorporated into calculations of skin resistance and end bearing resistance of piles. The proposed temperature-dependent model is an extension of the modified β method for determining the ultimate pile bearing capacity of unsaturated soils under drained conditions. Employing the proposed model, a parametric study was carried out to evaluate the ultimate pile bearing capacity for hypothetical clay and silt soils at temperatures ranging from 25 °C to 55 °C. For both clay and silt, the results indicated that the ultimate pile bearing capacity varies with an increase in temperature. Different trends with temperature were observed for clay and silt. A monotonic increase in pile resistance was observed in clays. For silt, the pile resistance increased at relatively low matric suction whereas it decreased at higher matric suctions.

scholarly journals Temperature-Dependent Model for Small-Strain Shear Modulus of Unsaturated Soils

2020 ◽  
Vol 146 (12) ◽  
pp. 04020136
Author(s):  
Farshid Vahedifard ◽  
Sannith Kumar Thota ◽  
Toan Duc Cao ◽  
Radhavi Abeysiridara Samarakoon ◽  
John S. McCartney
Keyword(s):  
Shear Modulus ◽  
Unsaturated Soils ◽  
Small Strain ◽  
Temperature Dependent ◽  
Small Strain Shear Modulus ◽  
Dependent Model ◽  
Temperature Dependent Model

scholarly journals Ultimate Bearing Capacity of Strip Foundations in Unsaturated Soils considering the Intermediate Principal Stress Effect

2020 ◽  
Vol 2020 ◽  
pp. 1-14
Author(s):  
Qing Yan ◽  
Junhai Zhao ◽  
Changguang Zhang ◽  
Jintai Wang
Keyword(s):  
Bearing Capacity ◽  
Principal Stress ◽  
Unsaturated Soils ◽  
Matric Suction ◽  
Ultimate Bearing Capacity ◽  
Intermediate Principal Stress ◽  
Shallow Foundations ◽  
Hyperbolic Function ◽  
Stress Effect ◽  
Intermediate Principal Stress Effect

The reasonable determination of ultimate bearing capacity is crucial to an optimal design of shallow foundations. Soils surrounding shallow foundations are commonly located above the water table and are thus in an unsaturated state. The intermediate principal stress has an improving effect on the unsaturated soil strength. In this study, the ultimate bearing capacity formulation of strip foundations in unsaturated soils is presented by using Terzaghi’s theory. The unified shear strength equation of unsaturated soils under a plane strain condition is utilized to capture the intermediate principal stress effect. Furthermore, two profiles of matric suction are considered and a hyperbolic function of the friction angle related to matric suction (φb) is adopted to describe strength nonlinearity. The validity of this study is demonstrated by comparing it with model tests and a theoretical solution reported in the literature. Finally, parameter studies are conducted to investigate the effects of intermediate principal stress, matric suction, and base roughness on the ultimate bearing capacity of strip foundations. Besides, the effect of strength nonlinearity is discussed with two methods representing the angle φb.

scholarly journals Model Test Ultimate Bearing Capacity of Bakau Piles Foundation on Soft Soil Deposit

2018 ◽  
Vol 1 (2) ◽  
pp. 94-99
Author(s):  
Muhammad O Yunus
Keyword(s):  
Bearing Capacity ◽  
Pile Foundation ◽  
Soft Soil ◽  
Ultimate Bearing Capacity ◽  
Small Scale ◽  
Test Results ◽  
Loading Test ◽  
Deep Foundation ◽  
Foundation Model ◽  
Ultimate Settlement

The pile foundation is one of the deep foundation types commonly used to support building loads when hard soil layers are deeply located. To determine the ultimate bearing capacity of a pile foundation of the load test results, there are several methods commonly used to interpretation test results such as Davisson method, Mazurkiewich method, Chin method, Buttler Hoy method and De Beer method. The aim of this study was to determine the characteristics of soft soil and bakau piles used in the study and to analyze the size of the bearing capacity ultimate of pile foundation that is modeled on a small scale in the laboratory. From the test results of material characteristics of the soil used is organic clay type with medium plasticity with specific gravity 2.75, liquid limit, LL = 50.36% and plasticity index, PI = 13.2%. While the results of testing the characteristics of bakau piles obtained average water content of 21.58%, tensile strength of 18.51 MPa, compressive strength of parallel fiber 23.75 MPa and perpendicular fiber 14.10 MPa, bending strength 106, 22 MPa, and strong split 29.91 MPa. From the result of loading test of the foundation model in the laboratory, it is found that the ultimate bearing capacity of the model without foundation is 41.00 kN with the ultimate settlement of 14.00 mm, the model of the 20 cm long bakau piles foundation is 52.00 kN with the ultimate settlement of 13.00 mm, the foundation model a 30 cm long bakau piles foundation of 54.00 kN with a 10.00 mm ultimate settlement, a 40 cm long bakau piles foundation model of 56.00 kN with an ultimate settlement of 8.50 mm.

Effect of Pile and Load Inclination on the Pile Resistance In both Compression and Tension

2014 ◽  
Vol 2 (1) ◽  
pp. 11-29
Author(s):  
Ahmad Jabber Hussain ◽  
Alaa Dawood Salman ◽  
. Nazar Hassan Mohammad
Keyword(s):  
Bearing Capacity ◽  
Inclination Angle ◽  
Theoretical Study ◽  
Pile Installation ◽  
Soil Failure ◽  
Inclined Pile ◽  
Uplift Resistance ◽  
Lift Forces ◽  
Batter Piles ◽  
Pile Resistance

      According to this theoretical study which was about loading of piles under different condition of loading (compression and up-lift forces ) and for deferent pile installation (vertical and inclined pile ) by which it called (positive batter pile ) when the inclination of the load and pile is in the same direction and called (negative batter pile) when the inclination of load is opposite to the pile inclination, and from studying these cases the results of analysis can be summarize in the flowing points: 1-Variation of load inclination on piles effects on the bearing capacity and uplift resistance. It was found that bearing capacity of the piles increase with increasing of load inclination up to the inclination angle (37.5ͦ) which represents the maximum bearing capacity and then the bearing capacity decrease with increasing of load inclination. 2- Variation of batter pile affects the bearing capacity of the pile and up-lift resistance. by which equivalent angle will be used as result between the load and piles inclination and this angle will be used in calculation of piles resistance . 3- It was noticed the shape of soil failure is highly affected by the inclination of pile. The shape of failure for the soil which is in contact with pile and this include (vertical and batter piles) is highly affected by the angle of inclination.

Development of allowable bearing capacity for strip foundations in unsaturated soils

2019 ◽  
Vol 114 ◽  
pp. 103138 ◽  
Author(s):  
Changguang Zhang ◽  
Benxian Gao ◽  
Qing Yan ◽  
Junhai Zhao ◽  
Lizhou Wu
Keyword(s):  
Bearing Capacity ◽  
Unsaturated Soils ◽  
Allowable Bearing Capacity
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