الفهرس 
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Abstract
At the end of the nineteenth century, problems of rising the ground water level in the agricultural lands were identified. This phenomena caused low crop yield of these lands. The Egyptian government at that time put plans to excavate open drains, in El-Delta, El-Fayoum and Middle Egypt. The government is responsible for the maintenance of the net of these drains and expands it to include all the Egyptian agricultural lands. Since 1975, the reuse of drainage water takes an important role in the Egyptian water policy and it is considered as one of the most important non-conventional water resources. It is estimated by 7.76 milliards cubic meter per year.
OBJECTIVES OF THE STUDY
The main objectives of this thesis could be classified into two parts:
a- investigating the effect of cohesion, unit weight, angle of internal friction and loads used for cutting and dredging operations on the factor of safety of side slope of drain, different side slopes are selected.
b- studying the actual reason of the drain bank failure under the effect of several factors namely:
• Seepage phenomenon.
• Velocity of the water in the drain.
• Critical shear stress on the drain wetted perimeter.
• Operation of the drains (weeds cutting- dredging operation) by heavy equipment.
CONCLUSIONS
Based on the present study the following conclusions can be drawn:
• Effects of cohesion, specific weight and angle of internal friction on the stability of slope and the corresponding factor of safety have been investigated.
• The F.S increases with the increasing values of cohesion(c), friction angle (Ø), distance from the edge of the drain (x*), drain side slope (s.s) and with the decreasing value of unit weight (γ).
• The F.S decreases with the increasing value of line load.
• c-Ø soil is more stable under heavy line load than c soil.
• The formulas used in calculating the mean velocity overestimate its value, therefore it is recommended to measure the actual mean velocity in future studies.
• Calculated velocity using Cowan’s equation is the nearest to the measured one than the other formulas in this research work.
• The main reason of increasing the cross section area of the drain under study (Kafr-Elzahera drain) than the corresponding design area is the slope failure, this leads to difficultly in workability.