scholarly journals A Full-Scale Field Study on Bearing Characteristics of Cast-in-Place Piles with Different Hole-Forming Methods in Loess Area

2019 ◽  
Vol 2019 ◽  
pp. 1-12 ◽  
Author(s):  
Zhijun Zhou ◽  
Tao Yang ◽  
Haobo Fan
Keyword(s):  
Bearing Capacity ◽  
Field Study ◽  
Load Transfer ◽  
Full Scale ◽  
Rotary Drilling ◽  
Loess Area ◽  
Side Resistance ◽  
Attenuation Rate ◽  
Scale Field ◽  
Forming Methods

This paper presents the results from a full-scale field study on the 3 different types of cast-in-place piles: rotary drilling piles (RDPs), manual digging piles (MDPs), and impact drilling piles (IDPs), for a bridge construction project of Wuqi–Dingbian Expressway, in Shaanxi. The results indicate that under the similar conditions, MDP exhibits the largest bearing capacity (11000 kN) in the loess area, followed by RDP (9000 kN) and IDP (8000 kN). And all tested values exceed the estimated value (7797.9 KN), indicating that the calculation formula of bearing capacity recommended by the Chinese standard is safe and conservative. During the load transfer process, the axial force attenuation rate of the pile body increases with pile side resistance. The average attenuation rate of MDP is the largest (24.2%), followed by RDP (19.72%) and IDP (16.69%). The bearing characteristics of these test piles are mainly pile side resistance, but the manual digging method created the least amount of disturbance to the soil around the pile, and due to its hole wall being rough, this enhances the pile-soil interactions. Hole-forming methods mainly affect the exertion of pile side resistance compared with pile end resistance. In view of pile side resistance and pile end resistance not taking effect at the same time, degree of exertion of these 2 resistances should be considered when designing cast-in-place piles in loess areas, and different partial coefficients should be used.

Performance of Driven Grouted Micropiles: Full-Scale Field Study

2021 ◽  
Vol 21 (2) ◽  
pp. 04020250
Author(s):  
Hamed Bayesteh ◽  
Mohammad Ali Fakharnia ◽  
Mahdi Khodaparast
Keyword(s):  
Field Study ◽  
Full Scale ◽  
Scale Field

FULL SCALE STATIC LOAD TEST ON THE SPIDER NET SYSTEM

2015 ◽  
Vol 77 (11) ◽  
Author(s):  
Helmy Darjanto ◽  
Masyhur Irsyam ◽  
Sri Prabandiyani Retno
Keyword(s):  
Bearing Capacity ◽  
Load Transfer ◽  
Static Load ◽  
Full Scale ◽  
Load Test ◽  
Static Load Test ◽  
Specific Element ◽  
Soil Stratum ◽  
Applied Loading ◽  
Shallow Footing

The Spider Net System Footing (SNSF) is a raft foundation system that commonly used in Indonesia. It contains a plate, downward ribs system for reinforcement, and the compacted filled soil. The ribs are in longitudinal and transversal, called as settlement rib and in diagonal direction, named as construction rib. This paper explores the load transfer mechanism along the plate, the ribs, filled soil and the base soil under the footing system. The mechanism is investigated by conducting full scale static load test on SNSF. Strain gauges were installed to monitor the strain increment of each footing elements during loading. 3D numerical analysis was also conducted to verify the experimental results. To analyze the results, Load-Ultimate Ratio Factor (L-URF) was proposed. L-URF was a ratio between ultimate soil bearing capacity of the SNSF and the applied loading at specific element. Higher the L-URF value means higher loading applied at its associate element. Both experimental and numerical results show that at the first stage the loading was fully carried out by the tip of the ribs and transferred to the soil stratum under the footing system. Increasing the loading, the ribs, plate, and filled soil altogether sustain the loading and then transferred to the soil stratum below the footing system. The results also affirm that SNSF generate higher bearing capacity compare with simple shallow footing.  

Axial compressive capacity of helical piles from field tests and numerical study

2013 ◽  
Vol 50 (12) ◽  
pp. 1191-1203 ◽  
Author(s):  
Zeyad H. Elsherbiny ◽  
M. Hesham El Naggar
Keyword(s):  
Bearing Capacity ◽  
Load Transfer ◽  
Numerical Study ◽  
Numerical Models ◽  
Field Tests ◽  
Reduction Factor ◽  
Full Scale ◽  
Cohesionless Soil ◽  
Soil Parameters ◽  
Helical Piles

The compressive capacity of helical piles in sand and clay is investigated by means of field testing and numerical modeling. The numerical models are conducted using the computer program ABAQUS and are calibrated and verified using full-scale load testing data. The calibration was accomplished by using reasonable assumptions regarding soil–pile interaction and soil parameters reported from the literature. The model was verified by comparing its predictions with observed load–displacement curves obtained from full-scale pile load tests. The verified numerical model was used to perform a parametric study considering different pile configurations and soil parameters to evaluate the compressive capacity and load-transfer mechanism of helical piles. The compressive capacity obtained from the numerical models is compared with that obtained from existing theoretical methods for calculating the capacity. It is found that the predictions of theoretical equations for piles in cohesionless soil vary largely depending on the choice of bearing capacity factors and proper failure criteria. The interaction of closely spaced helices on the capacity of a helical pile is also evaluated. A bearing capacity reduction factor, R, and helix efficiency factor, EH, are proposed to evaluate the compressive capacity of helical piles in cohesionless soil considering an industry-acceptable ultimate load criterion corresponding to settlement equal to 5% of helix diameter, D.

The Behavior of Piles Driven in Clay. II. Investigation of the Bearing Capacity Using Total and Effective Strength Parameters

1973 ◽  
Vol 10 (1) ◽  
pp. 86-102 ◽  
Author(s):  
J. I. Clark ◽  
G. G. Meyerhof
Keyword(s):  
Bearing Capacity ◽  
Load Transfer ◽  
Full Scale ◽  
Approximate Theory ◽  
Strength Parameters ◽  
Pile Shaft ◽  
Model Pile ◽  
Shearing Strength ◽  
Low Sensitivity ◽  
Large Model

This paper outlines research of large model piles and some full scale piles driven into insensitive clay to study the phenomenon of load transfer and the effect of pile driving on the soil. It is divided into two parts. Part I dealt with the stress field set up by driving a large model pile into an instrumented clay bed and the stresses measured for some full scale timber piles. Part II presents an evaluation of the load carrying capacity of the model pile and compares the results with full scale load tests. Soil properties are evaluated in terms of effective stress for an estimate of the bearing capacity of the piles.The short term bearing capacity of the pile shaft and base can be estimated by conventional methods based on the undrained shearing strength of the clay at the time of driving. However, after several load cycles and for long term bearing capacity, closer estimates are obtained by use of the effective skin friction and shearing strength parameters from drained tests. Previous bearing capacity theory can be used for estimating the ultimate base capacity and an approximate theory is presented to estimate the average effective radial stress on the pile shaft in connection with the ultimate shaft capacities. This proposed approach is supported by observations in some clays of low sensitivity, but requires further research in other types of clays.

FIELD-TESTING BIOREMEDIATION TREATING AGENTS: LESSONS FROM AN EXPERIMENTAL SHORELINE OIL SPILL

1997 ◽  
Vol 1997 (1) ◽  
pp. 707-712 ◽  
Author(s):  
Alan J. Mearns ◽  
Albert D. Venosa ◽  
Kenneth Lee ◽  
Michael Salazar
Keyword(s):  
Field Study ◽  
Oil Spill ◽  
Large Scale ◽  
Sandy Beach ◽  
Field Testing ◽  
Full Scale ◽  
Scale Field ◽  
Large Scale Field

ABSTRACT A 14-week, large-scale field study in Delaware demonstrated that, on a moderately exposed sandy beach, nutrients, not oil-degrading microorganisms, were the primary factors limiting biodegradation. The results are reviewed in the context of lessons and guidelines for a full-scale bioremediation response.

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