scholarly journals Nonlinear Stress Analysis of Flexible Pile Composite Foundation by Energy Method

2018 ◽  
Vol 2018 ◽  
pp. 1-9
Author(s):  
Youping Wu ◽  
Liangming Fu ◽  
Wenping Wu ◽  
Yuanyuan Cao ◽  
Xuanyang Zhou
Keyword(s):  
Potential Energy ◽  
Energy Method ◽  
Load Transfer ◽  
Relative Displacement ◽  
Composite Foundation ◽  
Laboratory Model ◽  
Energy Principle ◽  
Nonlinear Stress ◽  
Modified Cam Clay ◽  
Flexible Pile

To calculate the stress of cement-soil pile (flexible pile) in composite foundation accurately and overcome the defective preposition that the pile and the soil are elastic, the nonlinear analysis and calculation of pile-soil stress by adopting the energy method are performed. First, on the basis of the universally adopted load transfer method, it is assumed that the friction and the relative displacement of the pile shaft conform with the elastic-plastic relationship. Then, the modified Cam-clay model is introduced to calculate the compressive amount of soil around the pile. Further, the stress and strain characteristics curve of the flexible pile is used to calculate the compression of the pile, deducing the energy equation of the pile and soil around the pile, establishing the total potential energy expression of the flexible pile composite foundation, and the load sharing value and the corresponding stress value of the pile-soil are obtained based on the minimum potential energy principle. Finally, this method is verified by indoor laboratory model test and the reported case. The results show that the calculated solutions are in agreement with the measurements; therefore, the calculation method is reasonable.

Field Study of Improvement Mechanism of Geogrid-Reinforced and Pile-Supported Embankment

2014 ◽  
Vol 587-589 ◽  
pp. 928-933 ◽  
Author(s):  
Feng Lian ◽  
Zhi Liu ◽  
Jie Xu ◽  
Qiang Wang ◽  
Xian Hu Hu ◽  
...  
Keyword(s):  
Load Transfer ◽  
Soft Soil ◽  
Composite Foundation ◽  
Replacement Ratio ◽  
Floating Pile ◽  
Pile Cap ◽  
Soil Arch ◽  
Better Than ◽  
End Bearing Pile ◽  
Pile Supported Embankment

Two experimental areas in a highway soft soil ground treatment project in Guangdong Province were designed to investigate the improvement mechanism of geogrid-reinforced and pile-supported embankment(GRPS).The experimental results showed: In End-bearing Pile Area,the differential settlement between pile and soil was bigger than that of Floating Pile Area,so the bearing capacity of soil was exerted to a certain extent in Floating Pile Area. The bearing efficacy of soil below the pile cap was little, so the replacement ratio of composite foundation could be calculated according to the pile cap dimension. The load transfer efficacy of the geogrid was better than that of the soil arch. Five kinds of methods were used to evaluate the soil arch in the fill and it was indicated that the results calculated by the BS8006 method and Carlsson method was close to the experimental data which was smaller than results calculated by Hewlett method and Terzaghi method, bigger than Guido method. Through the analysis of the pile-soil stress ratio, the improvement mechanism of the two types of GRPS were revealed.

Model and theoretical seismicity

1967 ◽  
Vol 57 (3) ◽  
pp. 341-371 ◽  
Author(s):  
R. Burridge ◽  
L. Knopoff
Keyword(s):  
Numerical Model ◽  
Potential Energy ◽  
Main Sequence ◽  
Magnitude Scale ◽  
Laboratory Model ◽  
Earthquake Mechanism

abstract A laboratory and a numerical model have been constructed to explore the role of friction along a fault as a factor in the earthquake mechanism. The laboratory model demonstrates that small shocks are necessary to the loading of potential energy into the focal structure; a large part, but not all, of the stored potential energy is later released in a major shock, at the end of a period of loading energy into the system. By the introduction of viscosity into the numerical model, aftershocks take place following a major shock. Both models have features which describe the statistics of shocks in the main sequence, the statistics of aftershocks and the energy-magnitude scale, among others.

A Global Extremum Principle in Mixed Form for Equilibrium Analysis With Elastic/Stiffening Materials (a Generalized Minimum Potential Energy Principle)

1994 ◽  
Vol 61 (4) ◽  
pp. 914-918 ◽  
Author(s):  
J. E. Taylor
Keyword(s):  
Potential Energy ◽  
Problem Formulation ◽  
Extremum Problem ◽  
Equilibrium Analysis ◽  
Minimum Potential Energy ◽  
Problem Statement ◽  
Energy Principle ◽  
Potential Energy Principle ◽  
Minimum Potential ◽  
Minimum Potential Energy Principle

An extremum problem formulation is presented for the equilibrium mechanics of continuum systems made of a generalized form of elastic/stiffening material. Properties of the material are represented via a series composition of elastic/locking constituents. This construction provides a means to incorporate a general model for nonlinear composites of stiffening type into a convex problem statement for the global equilibrium analysis. The problem statement is expressed in mixed “stress and deformation” form. Narrower statements such as the classical minimum potential energy principle, and the earlier (Prager) model for elastic/locking material are imbedded within the general formulation. An extremum problem formulation in mixed form for linearly elastic structures is available as a special case as well.

Laboratory-scale pull-out tests on a geothermal energy pile in dry sand subjected to heating cycles

2020 ◽  
Vol 57 (11) ◽  
pp. 1754-1766
Author(s):  
Rehab Elzeiny ◽  
Muhannad T. Suleiman ◽  
Suguang Xiao ◽  
Mu’ath Abu Qamar ◽  
Mohammed Al-Khawaja
Keyword(s):  
Load Transfer ◽  
Pressure Sensors ◽  
Temperature Sensors ◽  
Heat Pumps ◽  
Laboratory Model ◽  
Ground Source Heat Pumps ◽  
Energy Pile ◽  
Pull Out ◽  
Energy Piles ◽  
Dry Sand

Ground source heat pumps coupled with energy piles operate intermittently, subjecting the piles to temperature cycles throughout their lifetime. The research presented in this paper focuses on studying the thermomechanical behavior of energy piles subjected to heating cycles. Laboratory model tests were performed at the soil-structure interaction (SSI) facility at Lehigh University. A fully instrumented model energy pile, embedded in dry sand, was subjected to different number of heating cycles followed by axial pull-out loading. Baseline (room temperature), five heating cycles (5HC), and 100 heating cycles (100HC) tests are reported in this paper. The soil was instrumented with temperature sensors and pressure sensors, while the pile was instrumented with temperature sensors, strain gauges, and pressure sensors. The test results showed that the peak pull-out loads for the baseline, 5HC, and 100HC were 2794 N, 3633 N (30% higher than baseline), and 3559 N (27% higher than baseline), respectively. It was also found that subjecting the pile to large number of daily heating cycles induced small degradation in the load transfer or the peak pull-out load in dry sand.

The Variational Principles of Coupled Systems in Fatigue Problem Undergoing Large Range Damage

2016 ◽  
Vol 835 ◽  
pp. 514-520
Author(s):  
Wen Feng Tan
Keyword(s):  
Fatigue Crack ◽  
Crack Initiation ◽  
Potential Energy ◽  
Large Range ◽  
Fatigue Crack Initiation ◽  
Form Solution ◽  
Coupled Systems ◽  
Energy Principle ◽  
Potential Energy Principle ◽  
Crack Initiation Life

The coupled systems of fatigue crack initiation problem undergoing large range damage is defined. The zero different work principle, coupled potential energy principle, coupled complementary energy principle in the coupled system is established. By using of coupled potential energy principle, Closed form solution about predicting fatigue crack initiation life of three-dimensional component which leads to large range damage is derived. Compared with reference [1], the close form solution derived from this some. It is proved that the method is correct. The method adopted in this paper is definite in mechanical concept,it can be widely used in analysis of predicting fatigue crack initiation life of various component which leads to large range damage.

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