Modification of some hydroulical problems of diyala weir

Dissertant

al-Doury, Sad Shawkat Sameen

University

University of Technology

Faculty

-

Department

Department of Building and Construction Engineering

University Country

Iraq

Degree

Master

Degree Date

2008

English Abstract

Weirs are one of the important hydraulic structures which are low-level dams constructed across a river to raise the stage of river sufficiently and to divert the flow in full, or in part, into a supplying canal or conduit for the purposes of irrigation, power generation, flood control, domestic and industrial uses, etc. This research aims to study of Diyala weir problems and compares it With the safe limit and proposes the treatment for these problems.

Diyala weir consists of the main weir, right bank scour sluice and left bank scour sluice, also two canals branch from the weir, Khalis breach and combined.

2-D steady-state finite element model (Geo-slope) SEEP / W has been used to analyze the seepage of water underneath the Diyala weir foundation. The floor thickness and stability against uplift pressure were calculated in different locations, however, the required thickness of the floor was found larger than that which exists (for point (A) which the end point of the stilling basin the required thickness is larger than that existing with ratio of about 18 %).

Also the safety against piping was calculated for the weir, this safety factor was found equal to 2.7, and this value is considered not enough for such structure. The hydraulic jump was also analyzed, it was found that the scour occurs due to the position of the hydraulic jump and the sequence depth of the hydraulic jump is higher than the tail water depth. Moreover, the effect of the seepage control devices such as cutoff, blanket, and filter trench in Diyala weir was analyzed to prevent or reduce seepage.

The results show that if the sheet pile upstream is used at depth (1 and 7) m it will reduce the uplift pressure at point (A) about (15.5-17.6) % and the exit gradient to ratios (15-17.3) %, while the downstream sheet pile at depth (1 and 7)m increases the uplift pressure to ratios (23-27) % and the exit gradient decreases to ratios of (91, 4-92) %. ■ The upstream blanket construct at distances (8m, 16m, and 32m), has reduced the uplift pressure at point (A) to ratios of (32.4, 36.4, and 43) %, and also reduces the exit gradient to ratios of (32.4, 35.1, and 43.2) %, while the downstream blanket at distances (8m, 16m, and 32m) increases the uplift pressure to ratios (10, 19, and 32.7) %, and the exit gradient reduces to ratios of (i 6.2, 21.6, and 32.4) %. Also the results show that the existence of filter trench at distance (16m, 19m and 22m) from the beginning of the weir structure reduces the uplift pressure to ratios of (92.7, 96.2, and 97-5) % respectively, and the filter trench reduces the exit gradient to ratios of (92-4, 95 J and 88.1) %.

However, some treatment procedures are.

suggested, these treatments cover both problems (seepage and hydraulic jump).

Main Subjects

Civil Engineering

Topics

• Dams
• Fluid dynamics
• Iraq

• APA
• MLA
• AMA

Language

English

Data Type

Arab Theses

Record ID

BIM-304979