Breast wall is a low stone wall which is constructed at the hill-side to support (retain) the natural bank of earth.
This wall standoff to protect a freshly cut or old surface of a natural hill face. It is mostly considered in the area where there is the action of weather and rainwater flowing over hill’s slope, to prevent the hill slides. It also prevents slides of unreliable soils.
1.1. Uses of Breast Wall
a. It is used at the sides of the road to retain the face of a natural bank of earth.
b. It is used to retain natural earth at the bank of the river.
1.2. Design of Breast Wall
Breast wall requires more base width because of surcharge loading exerted by the earth. The height of the breast wall is not supposed to exceed 3 meters because there is a higher possibility of overturning and sliding.
The design of breast wall is done based on the height of the wall, the nature of the backing and the slope of cutting. Weep holes should also be provided at regular interval to reduce the saturated earth pressure at the wall.
Breast wall is designed such that the line of pressure should be normal to the earth pressure or thrust.
1.3. Advantages of Breast Wall
i. It prevents the soil on a natural slope of embankment from sliding down due to the effects of weather like erosion, heavy rainfall etc.
ii. It can also be used in hydraulic structures.
iii. It plays a great role to control natural disasters like a landslide, slope failure, etc to some extent.
iv. It is economical.
v. Local materials and manpower can be utilized to construct.
vi. It enhances the safety of road users.
1.4. Disadvantages of Breast Wall
i. It is difficult as well as risky to construct breast wall in hilly areas.
ii. As it is constructed in a steep slope, high chance of overturning and sliding.
iii. Maintenace and repair work is quite tedious.
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