Effect of stress level of surrounding soil on bored pile capacity in sand

مقدم أطروحة جامعية

Akubi, Sayf Imad

مشرف أطروحة جامعية

Mahmud, Muhammad Abd al-Latif
Shallash, Qays Taha

الجامعة

الجامعة التكنولوجية

الكلية

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القسم الأكاديمي

قسم هندسة البناء و الإنشاءات

دولة الجامعة

العراق

الدرجة العلمية

ماجستير

تاريخ الدرجة العلمية

2012

الملخص الإنجليزي

The bearing capacity of piles still a subject for discussion and not fully understood yet; for this purpose piles behavior was studied using field tests, centrifuge tests, small scale model tests and numerical techniques.

For economy purposes small scale models and numerical techniques are usually used to investigate piles behavior.

The finite element method was used in this study to simulate the cases of axially loaded bored piles embedded in dense and medium sand.

It is well known and stated in literature that increasing stress level will lead to decrease angle of internal friction and the shear strength of sandy soil.

For this purpose, and to study the effect of stress level deeply, an empirical equation account for reduction of angle of internal friction with increase of stress level were implied in an existed finite element program adopting hyperbolic soil model.

As a result from this development, the angle of internal friction becomes variable and varies for each element according to its stress level.

A problem selected from literature and reanalyzed using the developed program to verify its ability to predict the pile capacity.

Investigation the effect of stress level on behavior of piles, bearing capacity factor ?? and distribution of shear stresses at soil-pile interface along pile shaft was made during this study by pass through a wide range of stresses by using piles with dimensions starting from laboratory dimensions and goes towards field dimensions with embedment ratio ?/? range (15, 20, 25, 30, and 40).

It was found from finite element analysis that, the stress level has a significant effect on end bearing of piles and unpronounced effect on shaft resistance.

As pile length (i.e.

stress level) increases, the bearing capacity factor ?? decreases up to a certain length beyond which the pile length increase has no influence on bearing capacity factor.

As embedment ratio increases, the bearing capacity factor increases up to a certain length beyond which the influence of embedment ratio vanishes.

It was also found that the distribution of shear stresses in soil-pile interface along pile shaft is random, non-linear and it has a tendency to increase with increasing overburden pressure.

The critical depth concept is examined in this study.

It is found that the critical depth has no significance effect on pile capacity for the piles geometry under consideration with embedment ratio ?/?= (15, 20, 25, 30, and 40).

Two mathematical models using STATISTICA computer package in form of simple equations are proposed depending upon the obtained results to simplify the analysis and to predict the capacity of piles readily with excellent regression.

التخصصات الرئيسية

العلوم الهندسية والتكنولوجية (متداخلة التخصصات)

الموضوعات

• ميكانيكا التربة

• APA
• MLA
• AMA

لغة النص

الإنجليزية

نوع البيانات

رسائل جامعية

رقم السجل

BIM-419364