Drilled pile behaviour in granular deposits

1988 ◽  
Vol 25 (2) ◽  
pp. 222-232 ◽  
Author(s):  
Hari D. Sharma ◽  
R. C. Joshi
Keyword(s):  
Skin Friction ◽  
Load Test ◽  
Soil Parameters ◽  
Oil Sand ◽  
In Situ Tests ◽  
Undisturbed Soil ◽  
Pile Shaft ◽  
Recompression Index ◽  
Load Tests ◽  
Pile Load Tests

The results of full-scale pile load tests, field monitoring, and laboratory tests on undisturbed soil samples have been used to compare soil parameters determined from in situ tests and in the laboratory for pile design in granular deposits. These results indicate a close agreement between the field- and laboratory-determined rebound or recompression index of oil sand. Also, a good agreement is indicated between field-measured and calculated pile head settlements. However, the measured average skin friction along the pile shaft in sandy till is about 20% more than the calculated values obtained from empirical and finite element analytical work using laboratory- and field-determined soil parameters. Theoretical t–z curves provided a good approximation of the field behaviour for the pile shaft resistance. Key words: drilled piles, belled piles, oil sand, skin friction, rebound, settlement, load test.

Performance of helical piles in oil sand

2009 ◽  
Vol 46 (9) ◽  
pp. 1046-1061 ◽  
Author(s):  
Mohammed Sakr
Keyword(s):  
Full Scale ◽  
Load Test ◽  
Test Results ◽  
Lateral Loads ◽  
Oil Sand ◽  
Deep Foundation ◽  
Helical Piles ◽  
Load Tests ◽  
Pile Load Test ◽  
Pile Load Tests

The results of a comprehensive pile load-test program and observations from field monitoring of helical piles with either a single helix or double helixes installed in oil sand are presented in this paper. Eleven full-scale pile load tests were carried out including axial compression, uplift, and lateral load tests. The results of the full-scale load tests are used to develop a theoretical design model for helical piles installed in oil sand. Test results confirm that the helical pile is a viable deep foundation option for support of heavily loaded structures. The test results also demonstrated that circular-shaft helical piles can resist considerable lateral loads.

scholarly journals Laboratory Research of Toe Resistance Based on Static Pile Load Tests in Different Schemes

2018 ◽  
Vol 28 (1) ◽  
pp. 172-181 ◽  
Author(s):  
Krzysztof Żarkiewicz
Keyword(s):  
Skin Friction ◽  
Applied Load ◽  
Load Transfer ◽  
Load Test ◽  
Laboratory Research ◽  
Load Tests ◽  
Pile Load Test ◽  
Friction Curve ◽  
Pile Load Tests ◽  
Surrounding Soil

Abstract Transfer of axial force from the head of a pile to the surrounding soil by skin friction and toe resistance is still uncertain. The results of the static pile load test are usually presented as settlement curve. This curve can be divided into two components: skin friction curve and toe resistance curve according to the settlement. Laboratory research of pile load test was carried out in two schemes: with skin friction and without skin friction. The study proved that the toe resistance with and without skin friction is not the same. Skin friction influence on toe resistance due to settlement. This phenomenon is not usually taken into account, but very often has a significant impact on axially applied load transfer. In the paper results of laboratory pile load tests id, different schemes were presented.

Predicting the Ultimate Bearing Capacity of Single Piles Based on CPTU

2011 ◽  
Vol 243-249 ◽  
pp. 4402-4407
Author(s):  
Yong Hong Miao ◽  
Guo Jun Cai ◽  
Song Yu Liu
Keyword(s):  
Load Test ◽  
Load Testing ◽  
Pile Capacity ◽  
Piezocone Penetration Test ◽  
Load Carrying ◽  
Load Tests ◽  
Pile Load Test ◽  
Single Piles ◽  
Pile Load Tests ◽  
Best Fit

Six methods to determine axial pile capacity directly based on piezocone penetration test (CPTU) data are presented and evaluated. Analyses and evaluation were conducted on three types piles that were failed during pile load testing. The CPT methods, as well as the CPTU methods, were used to estimate the load carrying capacities of the investigated piles (Qp ). Pile load test were used to determine the measured load carrying capacities (Qm). The pile capacities determined using the different methods were compared with the measured pile capacities obtained from the pile load tests. Two criteria were selected as bases of evaluation: the best fit line for Qp versus Qm and the arithmetic mean and standard deviation for the ratio Qp /Qm. Results of the analyses showed that the best methods for determining pile capacity are the CPTU methods.

A note on pile load test interpretation

1970 ◽  
Vol 7 (4) ◽  
pp. 479-481
Author(s):  
K. Peaker
Keyword(s):  
Soil Type ◽  
Test Procedure ◽  
Load Test ◽  
Building Code ◽  
Test Interpretation ◽  
Load Tests ◽  
Pile Load Test ◽  
Pile Load Tests ◽  
Pile Type

Pile load tests are normally carried out in accordance with A.S.T.M. or other building code specifications without regard to the actual pile type or soil type. The example quoted indicates that the test procedure may lead to incorrect interpretation of failure and conservative design.

Design of axially and laterally loaded piles using in situ tests: A case history

1985 ◽  
Vol 22 (4) ◽  
pp. 518-527 ◽  
Author(s):  
P. K. Robertson ◽  
R. G. Campanella ◽  
P. T. Brown ◽  
I. Grof ◽  
J. M. O. Hughes
Keyword(s):  
Ground Surface ◽  
Cone Penetration Test ◽  
Load Test ◽  
Penetration Test ◽  
Cone Penetration ◽  
In Situ Tests ◽  
Below Ground ◽  
Load Tests ◽  
Pile Load Test ◽  
Laterally Loaded

A 915 mm diameter steel pipe pile was driven and tested by the B.C. Ministry of Transportation and Highways as part of their foundation studies for the proposed Annacis channel crossing of the Fraser River. The pile was driven open ended to a maximum depth of 94 m. The pile was tested axially to failure when the pile tip was at depths of 67, 78, and 94 m below ground surface. Following the final axial load test, the pile was loaded laterally to a total deflection at the ground surface of 150 mm. A slope indicator casing was installed in the pile to monitor the deflected shape during lateral loading.Adjacent to the pile, a piezometer-friction cone penetration test (CPT) and a full-displacement pressuremeter profile were made. Results of the axial and lateral load tests are presented along with the data from the CPT and the full-displacement pressuremeter tests. Results of several analyses using the data from the CPT and pressuremeter tests to predict the axial and lateral performance of the pile are presented. A comparison and discussion is presented between the predicted and measured axial and lateral behaviour of the pile, for which excellent agreement was found. Key words: pile load test, cone penetration test, pressuremeter test.

scholarly journals Large-diameter helical pile capacity – torque correlations

2017 ◽  
Vol 54 (7) ◽  
pp. 968-986 ◽  
Author(s):  
Jared Harnish ◽  
M. Hesham El Naggar
Keyword(s):  
Large Diameter ◽  
Failure Criteria ◽  
Load Test ◽  
Ultimate Capacity ◽  
Pile Capacity ◽  
Shearing Resistance ◽  
Helical Piles ◽  
Torque Capacity ◽  
Load Tests ◽  
Pile Load Tests

Large-diameter helical piles are utilized increasingly to support heavy structures. Both the magnitude of the required installation torque and the pile capacity can be directly attributed to the soil shearing resistance developed over the embedded area of the pile including the shaft and helical plates. Hence, the pile capacity can be correlated to installation torque. Such correlations are widely used in the helical pile industry as a means for quality control and quality assurance. In the current study, a total of 10 test piles were installed while monitoring the installation torque continuously with depth. The recorded installation torque profiles were demonstrated to be accurate and repeatable. Field pile load tests were conducted and their results were analyzed to determine the interpreted ultimate capacity of the test piles. The results demonstrate that the ultimate capacity of large-diameter helical piles can be interpreted from pile load test data employing the failure criteria proposed by Elkasabgy and El Naggar in 2015 and Fuller and Hoy in 1970. The measured installation torque and corresponding ultimate capacity values were employed to define torque–capacity correlation (Kt) based on embedded pile area. It was demonstrated that the proposed Kt is suitable for large-diameter helical piles.

scholarly journals Behaviour of Single and Group Helical Piles in Sands from Model Experiments

2019 ◽  
Vol 278 ◽  
pp. 03007
Author(s):  
Jongho Bak ◽  
Byung-hyun Choi ◽  
Junwon Lee ◽  
Jonghwan Bae ◽  
Kicheol Lee ◽  
...  
Keyword(s):  
Rotation Speed ◽  
Axial Loading ◽  
Complete Removal ◽  
Drilled Shafts ◽  
Load Test ◽  
Oil Sand ◽  
Driven Piles ◽  
Pile Installation ◽  
Helical Piles ◽  
Pile Load Tests

Mainly used foundations of oil sand plants are drilled shafts or driven piles. As environmental regulations become increasingly strict, complete removal of the foundation is becoming more important during the step of plant dismantling. However, it is difficult to remove completely drilled shafts or driven piles which are deeply installed to obtain more bearing capacity. Helical piles can be easily removed and recycled after use. This study analyses the behaviour of single and group helical piles in sands. For single helical piles, pile load tests of helical piles were conducted varying helix spacing, rotation speed and weight of axial loading during pile installation. The single pile tests determined the optimal helix spacing, rotation speed, weight of axial loading during pile installation. And then, pile load test of group helical piles was performed varying pile spacing from the centre place of upper connector based on the optimal installation conditions.

scholarly journals Influence of time on the bearing capacity of precast piles

2013 ◽  
Vol 35 (4) ◽  
pp. 65-74 ◽  
Author(s):  
Kazimierz Gwizdała ◽  
Paweł Więcławski
Keyword(s):  
Bearing Capacity ◽  
Cohesive Soils ◽  
Geotechnical Parameters ◽  
Well Control ◽  
Time Points ◽  
Pile Shaft ◽  
Field Investigations ◽  
Load Tests ◽  
Pile Load Tests ◽  
Change Of Microstructure

Abstract One of the most popular types of foundations in layered subsoil with very differentiated soil shear strengths are precast piles. One of the reasons is the fact that we can well control the driving process during the installation of these piles. The principles of the assessment of bearing capacity and settlements of the piles given by Eurocode 7, concentrate on two main methods, i.e., Static Pile Load Tests (SPLT) and Dynamic Driving Analysis (PDA). However, the evaluation of real load-settlement curve for piles being driven in layered subsoil, where noncohesive and cohesive soils occur alternately, is neither easy nor straightforward. In the paper, the results of both SPLT and PDA tests for objects on the highways in Poland are presented. Field investigations carried out at various time points since the installation of piles (from 7 to 90 days) revealed an increase of bearing capacity with time. The reason for this may be a change of the soil state near the piles due to their driving (displacement of piles) as well as a change of microstructure at the contact between soil and pile shaft. The results of load tests were referred to the geotechnical parameters of the subsoil, which was recognized by means of traditional borings and CPTU tests. The results of tests allow phenomena occurring with time to be assessed and bearing capacity of precast piles to be predicted.

A new socket roughness factor for prediction of rock socket shaft resistance

2001 ◽  
Vol 38 (1) ◽  
pp. 138-153 ◽  
Author(s):  
J P Seidel ◽  
B Collingwood
Keyword(s):  
Compressive Strength ◽  
Unconfined Compressive Strength ◽  
Resistance Coefficient ◽  
Complex Problem ◽  
Load Test ◽  
Technical Literature ◽  
Analysis And Design ◽  
Shaft Resistance ◽  
Load Tests ◽  
Pile Load Tests

Prediction of rock socket shaft resistance is a complex problem. Conventional methods for predicting the peak shaft resistance are typically empirically related to unconfined compressive strength through the results of pile load tests. It is shown by reference to international pile socket databases that the degree of confidence which can be applied to these empirical methods is relatively low. Research at Monash University has been directed at understanding and then modelling the complex mechanisms of shear transfer at the interface between the socketed piles and the surrounding rock. Important factors that affect the strength of pile sockets have been identified in laboratory and numerical studies. With a knowledge of the effect of these factors, the reasons for the large scatter around traditional empirical correlations can be deduced. A computer program called ROCKET has been developed which encompasses all aspects of the Monash University rock socket research. This program has been used to develop design charts for rock-socketed piles based on unconfined compressive strength and a nondimensional factor which has been designated the shaft resistance coefficient (SRC). Implementation of the SRC method in design requires an estimate of the likely socket roughness to be made. Very few researchers or practitioners have measured socket roughness, so there is little available guidance in selection of appropriate values. Although many socket load tests are described in the technical literature, the physical parameter which is regularly missing is the socket roughness. With a knowledge of the shaft resistance, and an estimate of all other relevant parameters, the authors have been able to back-calculate the apparent socket roughness using the SRC method. Based on the back-calculated roughness data, socket roughness guidelines for use in analysis and design of rock sockets have been proposed. Using these roughness guidelines, it is shown that the SRC method is able to predict the scatter observed in previously published international load test databases.Key words: rock socket, drilled shaft, shaft resistance, roughness, shaft resistance coefficient.

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