What is dam sloughing?

IF the downstream toe of dam gets saturated by piping or any seepage action, it will get eroded and forms small slide or small slump. The slump will create steeper face which again gets eroded due to seepage and form slump again. This progressive removal of saturated soil is called sloughing.

What is piping in seepage?

Piping is a form of seepage erosion and the general name for the adverse effects of groundwater flow on soil stability. High seepage pressures may remove soil material to such an extent that geotechnical structures may, and do, collapse. Several terms have been used in the literature to classify this seepage erosion.

What is piping in hydraulic structures?

The actual word “piping” refers to the development of channels, which form at the downstream side of the structure where the flow lines converge and high seepage pressures occur. If this process continues, the eroded channels may reach upstream and cause the total collapse of the structure.

What is piping in soil?

Soil piping is a naturally occurring, hydraulic process that leads to the development of macropores (large, air-filled voids) in the subsurface that are associated with landslides and collapse subsidence. It is most commonly associated with ‘soil’, a term that has contextual meanings.

What is drainage filter in dam?

In a zoned dam, the filter is placed between the core and the downstream shell zone. A longitudinal ‘chimney’ drain of gravel material collects the intercepted seepage flow and carries it to the base of the chimney. The transverse drains then conveys the water to the toe drains outside the embankment.

How do I stop piping?

To prevent the possibility of erosion and piping, following approaches are used:

1. By providing cut off wall at downstream side.
2. Increasing the flow path by providing impervious blanket.
3. Use of protective filter.

What is piping effect in earthen dam?

A dam may breach within a few hours after evidence of internal erosion becomes obvious. Piping is a related phenomenon and is defined as the progressive development of internal erosion by seepage, appearing downstream as a hole discharging water.

What is seepage force?

The frictional drag of water flowing through voids or interstices in rock causing an increase in the intergranular pressure (i.e. the hydraulic force per unit volume of rock or soil which results from the flow of water and which acts in the direction of flow).

How do I control seepage in embankment dams?

Control at points of seepage exit can be accomplished after construction by installation of toe drains, relief wells, or inverted filters. Weep holes and relief drains can be installed to relieve water pressure or drain seepage from behind or beneath concrete structures.

Which of the following filters are also known as chimney drains?

4. ____________________ is provided when large scale stratification occurs. Explanation: A vertical filter (or inclined u/s or d/s) is placed along with the horizontal as to intercept the seeping water effectively in case of large stratification. This arrangement is called a chimney drain.

What causes piping failure?

The common causes of pipe failure are corrosion, water velocity, clogging, movement, and extreme temperatures. To prolong its use, ensure that the appropriate class, grade, and material are used before installation.