Common causes of downfalls of Dam Structures
A dam is a block across flowing water that opposes, directs or slows down the flow, often creating a store, lake or captivities. Most dams have a section named a spillway or weir over or through which the water passes and have some hydroelectric power generation systems installed.
Dams are like ‘installations containing dangerous forces’ due to the huge impact of a possible destruction on the normal population and the environment.
Generally dam failures are happen rarely but can do huge damage and loss of life, it happens as the dam structures are constrained to horizontal loading from the water head behind. The pressure comes from the water to the dam materials such as the adjoining geology and size of the reservoir which are very new in the case of dam structures.
Common reasons of downfalls of Dam Structures: The most known reason of the downfall of the dam structures is overtopping which is happen either for exceeding that is something concerned with the design of the spillway.
• Overtopping: It is happen when water slopping over the top of a dam and become a reason of dam failure. The two major factors of the overtopping failure are one id created due to surface elevation exceeds the total structural elevation profile and the other one is the over washes of the waves.
• Foundation defects and Slope instability: Foundation defects with settlement and slope instability causes most of the dam failures.
• Cracking: happens by the movements like the natural setting of a dam.
• Water Violating.
• Subsidence and the movement of the foundation.
• Uplift form the ground and sliding of the structure.
• Variation in temperature.
• Dynamic blasting in the nearby areas.
• Seismic load action.
• Wave action on the structure and weak energy absorption.
• Higher amount of silting.
• Loosing shear capacity of the concrete.
Reasons of downfalls of Earth Dam Structures: In case of earth dam, that unique materials that are used for the structure is made from the earth materials is nearby the side and makes the structure to be mixed in nature showing different properties in different conditions of weather and bring variations in the physical properties. There are other reasons of the earth dam failure are: insufficient spillways, piping, failure of the structure etc. and many more.
Reasons of downfalls of Gravity Dam Structures: Gravity dams are made from concrete and masonry and the major causes of failures of these structures are: soil erosion, failed construction joints, poor material etc.
Reasons of downfalls of Arch Dam Structures: This dam is different as it has plane stresses existing and thrust and these factors are caused for the design of the structure and completely dependent on the conditions of soil and rock. The failure happens for lack of structure, penstock vibration and insufficient grouting action.
Reasons of downfalls of Buttress Dam Structures: They have the horizontal forces transferred to the rock foundation and carried out by water pressure which is analyzed for the sliding and overturning failure of dam structure. The main reasons of failure are: alternate freeze and thraw cycles, masonry etc.