# Embankment

2 de Sep de 2015
1 de 22

### Embankment

• 2. INTRODUCTION  When the sub grade line of highway is raised the existing ground level, the embankment is constructed.
• 3. NECESSITY OF Constructing THE PAVEMENT  Make the subgrade level above the ground water table  Satisfy the vertical alignment of a highway.
• 4. Design and construction stages  Evaluate the embankment height  Embankment materials  Compaction and its materials  Construct the embankment with equal slopes  Check settlement
• 5. Design of embankment  The embankment design elements are as follows….. Selection of dimensions Slopes Settlement analysis Materials Drainage
• 6. Selection of dimensions  The dimensions are select due to the roadway width , height and its side slopes. Width - its fixed as per IS recommendations . It may be single, two and multiple lane roads. Height - its based on desired grade line of the highway and the topography Side slope - in this basis generally flat slope is considered , because of the erosion control
• 7. Stability of slopes  Sloping surfaces are subjected to get shearing stresses at all intervals  If the shear stress more, then a surface is formed at a failure.  For the failure of slope the main reason is shear stresses are non uniform at all intervals  If the failure problem arrives means correct the slope shape to the normal sloping points
• 8. Types of slopes  Infinite slope: it’s the type of slope which is give equal extent and uniform slope to the normal surface conditions.  Finite slope: in this type the slope having limited height
• 9. Settlement and stability foundation It occur due to compression of fill material in the subgrade. Compaction is the main program of settlement If the compaction is not even then the settlement is collapse F.o.s should be more than three means there is no other problems due to settlement, if problem arise convert equal stresses depends upon F.O.S
• 10. Selection of embankment materials  The embankment materials should have the strength and stability.  Silts and clays are not a constructing soil,  On the site locating soil is best to the embankment foundation
• 11. The soil properties may contain the following characteristics  Soil have more strength and stability.  High plastic soils should be avoided during construction  Soil should have good drainage properties.  Clay soils are not satisfy the drainage conditions  The high density compacted soils should be prepared in the construction.
• 12. Drainage system  Embankment height is highly notified on 8m.  Such a locations some of damages may occur the cause of rain water  When rain water falls highly means erosion will occur on the slopes and shoulders.  This erosion may be turn into road pavement
• 13. Cont…  Here this possible cause embankment drainage is important one.  Soil type, height of embankment, high rainfall, are the reasons may appear the erosion  Let us we the following image how to the embankment drainage working on a highway
• 15. EMBANKMENT WEAK SOILS  In the location weak soil attained special designs are considered  If the un suitable soil presents in the subgrade means the soil remove that place by the use of deep foundation  The structure design conditions are not satisfy, immediately the structure redesigned by the use of light weight materials.
• 16. Cont…  Removing poor materials in subgrade  Replace good resisting materials  Treating the soil such improve the properties
• 17. construction  The construction techniques may depends upon the following cases..  Borrow pit – excavate soil  borrow pit may represent the IRC classification.  It should locate the road boundary  It should be in rectangular shape  Every borrow pits having a distance of 5m  The maximum depth is 1.5m… this depth is limited depth of borrow pit
• 18. Cleaning of natural ground • This process may undertaken the earthwork for a embankment construction • Its consist of removing trees, roots, obstacles etc.. • The top soil is retained and highly compacted soil is placed on the surface
• 19. Compaction due to original ground  Dry density of soil may be have the density of 90%.  In the original ground (that means loosening soil) watering and rolling is provided in the layers of 25cm.  This watering, rolling treatment has extended to a depth of 0.5m.
• 20. Compaction of embankment  Earlier embankment is constructed by rolling  Soil is dumped on the ground surface  The water content should be in 2%  Required water added on the site  Soil spread along over the surface with a depth of 25cm  The mechanical equipment is needed to compaction
• 21. Cont…  Standard three wheel steel tyred rollers are used to the compaction  Compaction of each layer is called as lift.  This main method is called as compaction