Effect of scaling factor on pile model test results

مقدم أطروحة جامعية

Ali, Ahmad Majid

مشرف أطروحة جامعية

Mahmud, Muhammad A.
Shallash, Qays Taha

الجامعة

الجامعة التكنولوجية

الكلية

-

القسم الأكاديمي

قسم هندسة البناء و الإنشاءات

دولة الجامعة

العراق

الدرجة العلمية

ماجستير

تاريخ الدرجة العلمية

2012

الملخص الإنجليزي

The present study investigates the behavior of model piles in sand constructed as bored and as driven piles, and how this can be utilized to get a link which may be used to expect the actual prototype behavior with assistance of statistical derived equations.

A total number of 40 model piles are divided into two groups according to the method of erection.

Firstly, 12 model piles are executed as bored piles.

Secondly, 28 model piles are constructed as driven model piles.

The model tests were carried out using sand of relative density equal to 31% corresponding to a dry unit weight of 16.5kN/m3.

All model piles are loaded to 200% of their working loads.

In this study, different parameters are considered such as the effect of length, diameter, and pile shape for model bored piles.

For driven piles, the effect of the driving energy (E), penetration value (set), pile to hammer weight (P/W) ratio, factor of safety (F.S) in addition to pile dimensions are considered.

The model bored piles results show that the pile diameter has more effect than the pile length where, it can be noted that there is a noticeable increase in pile capacity when the diameter changes from 1.1 to 2.1cm.

On the other hand, it can be seen that there is slightly increase in pile capacity when the model pile length transfers from 30 to 40cm because the side friction has a small value at these lengths and therefore, is utilized during the early stages of loading.

Moreover, the observed capacities obtained from the laboratory tests results are less than the predicted capacities which are estimated using theoretical equations for a safety factor equal to 1.5.

It was also noted that the increasing rate of model pile capacity decreases with the increase of pile diameter due to particle size effects (this state coincides with principle of reduction of the angle of internal friction when pile diameter/width increase).

In model driven piles, the tests performed using a factor of safety of 2 exhibit higher bearing capacity than those tests carried out using a factor of safety equal to 1.5.

The working load used in the tests is calculated by dividing the ultimate pile capacity computed using theoretical equation and Hiley formula for model bored and driven piles respectively, by a factor of safety of 1.5 and 2.

The penetration value (set) influences with the diameter/width more than the pile length for a constant driving energy.

The ratio of pile capacity calculated by dynamic formula (Hiley) to pile capacity estimated by theoretical static equation is increased with the increase of pile diameter.

As well as, piles which are driven by heavy hammer reveal that precedence in the bearing capacity than the light hammer at same driving energy.

Finally, the two statistical derived equations using the computer program (STATISTICA) for model driven and bored piles manifested a reasonable convergence between the models and prototype results.

The results obtained from the statistical derived equations display the coefficient of determination (R2) is (95.7% and 93.3%) for model bored and driven piles respectively.

التخصصات الرئيسية

العلوم الهندسية والتكنولوجية (متداخلة التخصصات)

• APA
• MLA
• AMA

لغة النص

الإنجليزية

نوع البيانات

رسائل جامعية

رقم السجل

BIM-418604