Seepage analysis through under Neath : hydraulic structures applying finite volume method

مقدم أطروحة جامعية

al-Bakri, Hisham Majid Jabir

الجامعة

الجامعة التكنولوجية

الكلية

-

القسم الأكاديمي

قسم هندسة البناء و الإنشاءات

دولة الجامعة

العراق

الدرجة العلمية

ماجستير

تاريخ الدرجة العلمية

2007

الملخص الإنجليزي

The origin of the study of seepage phenomena in porous media goes back to Darcy (1856).

Later, experiments were made by many investigators on a wide scale data.

The mathematical Theories of the flow of ground water are the fundamentals which are used in the works carried out by all who study and presented solutions for percolation problems.

New mathematical methods based upon the presently known results of the theory of functions and the equations of mathematical physics, have been developed.

However, such mathematical approaches (analytical or closed — form solutions) are practical or applicable only when the boundary of the region of seepage is clearly defined and the soil medium is homogeneous and isotropic with respect to permeability, that is, the ratio of the principal permeabilities is constant and the directions of the principal axes of permeability reserve constant direction.

However, if, as is often the case, the region is non-homogeneous and non uniformly anisotropic, a solution by analytical methods is no longer practical, for example the closed — form solutions for the seepage characteristics of even simple structures founded in layered media offer considerable mathematical difficulty.

Therefore, recourse to the recently developed numerical methods, based on automatic computations, becomes necessary.

This has opened a new era in analysis and design for a wide range of seepage problems, and it has permitted the incorporation into analysis and design of complex factors such as nonlinear behavior, non-homogeneities, and discontinuities that cannot be readily handled by the closed — form and empirical procedures used previously.

For such problems, the finite difference method and the finite element methods have been presented for use with an electronic digital computer.

Concerning the finite difference method, it was perhaps the main numerical technique employed in geotechnical engineering before the era of the finite element method.

However, the general finite difference approach for analyzing seepage problems through soils comprising irregular zones of different permeabilities and anisotropic properties is still not developed or difficult to discretise.

On the other hand, the development of the finite element method provided a suitable alternative Which could be applied to such structures and was flexible enough to accommodate a wide range of seepage problems.

It is obvious that both methods are based on the principle of discretisation, that is, a procedure in which a complex problem of large extent is divided, or discretised, into smaller equivalent units, or components. The finite volume method had been used because it is easy as finite difference, powerful as finite element and also easy to program and implement.

The finite volume method is not limited to Cartesian grids but can be used with a grid in any orthogonal coordinate system.

This means one can use rectangular elements in Cartesian coordinate, sector elements in polar coordinates, and cuboids elements in three-dimensional Cartesian coordinates.

It is applied to different types of material, structures, boundary conditions and it shows good results in comparison to ones done by finite element method. The finite volume method adopted in this study to obtain solutions for seepage tlow through porous media comprising irregular zones and compares the results obtained with finite element method.

In addition, an investigation has been done to show the effect of anisotropy of foundation soil on the uplift pressure and exit gradient and compare it with the isotropic soil foundation.

In addition, an evaluation of the effect of location and inclination of the cut-offs on the uplift pressure and exit gradient.

In addition, an evaluation of the effect of impermeable solid rock located in the foundation.

All of the previous evaluations have been done in the comparison with finite element results and showed accurate results as finite element method. The finite volume method shows a good response easy to implement in anisotropy, non-homogeneous material, and discontinuous boundary.

التخصصات الرئيسية

الهندسة المدنية

الموضوعات

• النماذج الرياضية

• APA
• MLA
• AMA

لغة النص

الإنجليزية

نوع البيانات

رسائل جامعية

رقم السجل

BIM-305448