CRFLOOD: A numerical model to estimate uplift pressure distribution in cracks in concrete gravity dams

Technical Report · Sun Nov 01 00:00:00 EST 1992

OSTI ID:7146976

Illangasekare, T; Amadei, B; Chinnaswamy, C ^[1]

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1. Colorado Univ., Boulder, CO (United States). Dept. of Civil Engineering

Knowledge of the magnitude and distribution of uplift pressures in cracks in concrete gravity dams is needed when assessing their stability and safety and in the design of rehabilitation schemes. In the conventional limit equilibrium approach for dam stability, the head distribution in all cracks is assumed to be uniform irrespective of the existence of drains and their operative conditions. This approach is conservative when the drains are in proper operating condition and are releasing some of the uplift pressure. Analytical studies on the effect of drains in reducing uplift in cracks have been reported in the literature. However, analytical solutions are limited to cracks of simple geometry and cannot be used to determine uplift under more realistic field conditions i.e., in cracks with variable aperture, surface roughness, irregular geometries and turbulent and transient crack flow conditions. These limitations can be overcome using numerical methods. The finite element method is used in this report as a tool to model uplift in cracks and quantify drain effectiveness. A general finite element program called CRFLOOD is proposed. On the outset, this report provides a brief review on how water flows in cracks and what are the governing equations for crack flow under steady and transient conditions. Then, finite element formulations for the different types of crack flow are presented. The finite element model is validated in three ways (1) by using closed-form solutions, (2) by using another but more limited finite element program, and (3) by comparison with experimental results. Finally, program CRFLOOD is used to conduct an extensive parametric study on the effect of several parameters on uplift and drain effectiveness.

• Research Organization: Electric Power Research Inst., Palo Alto, CA (United States); Colorado Univ., Boulder, CO (United States). Dept. of Civil Engineering
• Sponsoring Organization: EPRI; Electric Power Research Inst., Palo Alto, CA (United States)
• OSTI ID: 7146976
• Report Number(s): EPRI-TR-101671-Vol.4
• Country of Publication: United States
• Language: English

Related Subjects

13 HYDRO ENERGY
DAMS
CRACKS
DRAINAGE
STABILITY
FINITE ELEMENT METHOD
HYDROELECTRIC POWER
PRESSURE EFFECTS
SAFETY ENGINEERING
VALIDATION
CALCULATION METHODS
ELECTRIC POWER
ENERGY SOURCES
ENGINEERING
NUMERICAL SOLUTION
POWER
RENEWABLE ENERGY SOURCES
TESTING
130200* - Hydro Energy- Site Geology & Meteorology