Why Is The Construction Of Embankment Necessary?

Why Is The Construction Of Embankment Necessary
User Guidelines for Waste and Byproduct Materials in Pavement Construction

EMBANKMENT OR FILL Application Description

INTRODUCTION An embankment refers to a volume of earthen material that is placed and compacted for the purpose of raising the grade of a roadway (or railway) above the level of the existing surrounding ground surface. A fill refers to a volume of earthen material that is placed and compacted for the purpose of filling in a hole or depression.

Embankments or fills are constructed of materials that usually consist of soil, but may also include aggregate, rock, or crushed paving material. Normally, the coarser fill materials are placed at or near the bottom or base of the embankment in order to provide a firm foundation for the embankment and also to facilitate drainage and prevent saturation.

The top portion of an embankment usually is constructed of relatively high-quality, well-compacted subgrade material that is capable of supporting the overlying pavement layers and imposed wheel loadings without deflection or undesirable movement. The fill material used throughout the remainder of the embankment must be capable of meeting applicable specification quality requirements and be capable of being placed and compacted at or close to its maximum achievable density.

  • The material is spread in relatively thin layers of 150 mm (6 in) to 200 mm (8 in) and each layer is compacted by rolling over it with heavy compaction equipment.
  • MATERIALS Soils Many different types of soils may be suitable for use in the construction of an embankment or fill, ranging from granular soils (sand and gravel), which are highly desirable, to the more finely sized soils (silt and clay), which are usually somewhat less desirable.

Certain types of soils (such as saturated clays and highly organic soils) are considered unsuitable for use as materials in embankment or fill construction. Regardless of the type(s) of soil(s) used to construct embankments or fills, the material should be well graded, capable of being well compacted, be within a proper range of moisture to optimize compaction, and be free of unsuitable or deleterious materials, such as tree roots, branches, stumps, sludge, metal, or trash.

Oversize Materials Some oversize materials (over 100 mm (4 in) in size), such as rocks, large stones, reclaimed paving materials, or air-cooled slags, can be used for the construction of embankment bases. Although the use of oversize materials can result in a stable embankment base, the oversize materials should have strong particles that do not readily break down under the action of construction machinery, but which have a range of sizes so that void spaces are at least partially filled.

MATERIAL PROPERTIES AND TESTING METHODS Some of the more important properties of materials that are used for the construction of embankments or fills include:

Gradation – well-graded fill materials that consist of two or more soil types, usually a mixture of granular and fine-grained soils, are most suitable for embankment construction. Because of the wide variety of soils that may be encountered, there is no universally recommended range of gradation for fill materials, although the maximum particle size should be less than 100 mm (4 in) so that it can be readily placed within a 200 mm (8 in) layer. Rock, or other oversize materials to be used as an embankment base, should consist of different size particles, with a specified maximum particle size. Unit Weight and Specific Gravity – fill materials can vary in unit weight over a fairly wide range, depending on the type of material and its moisture content. Fill materials that are relatively low in unit weight offer the advantage of transmitting less dead load to the underlying soil that supports an embankment. There are usually no specified requirements for a minimum or maximum unit weight, either before or after compaction. Moisture-Density Characteristics – the compaction characteristics (optimum moisture content and maximum dry density) of a soil fill material are the most important single property that affects embankment performance. Most specifications for embankment construction require the compacted fill material to have an in-place density that is within a certain percentage (usually 95 percent or greater) of the maximum dry density at a moisture content that is within a certain percentage (usually 3 percent or less) of optimum. The optimum moisture and maximum dry density of fill material(s) are determined in advance in the laboratory by means of either standard or modified moisture-density compaction tests. These tests methods are applicable for soils or earthen fill materials. Moisture-density characteristics cannot usually be determined for oversize (over 100 mm (4 in) materials) materials. Shear Strength – the shear strength characteristics (cohesion and/or internal friction) are indicative of the ability of a fill material to support loads that are imposed upon it under given drainage conditions. Shear strength characteristics are not always specified for earthen fill materials, but are determined by triaxial compression or direct shear testing and are used to compute the slope stability of an embankment. Compressibility – compressibility refers to the consolidation or settlement characteristics of a material under long-term loading conditions. The compressibility of a fill material is related to its shear strength, degree of compaction, void ratio, permeability, and degree of saturation. The settlement characteristics of an earthen fill material are determined by one-dimensional consolidation testing. Some settlement of an embankment or fill will occur during its construction, while the remainder of the settlement (if any) will occur in the postconstruction period. Bearing Capacity – bearing capacity refers to the ability of a fill material to support the loadings imposed upon it over the life of the facility without undue settlement, volume change, or structural damage. Bearing capacity can be determined by laboratory testing and by field load tests. Permeability – permeability or hydraulic conductivity refers to the ability of a soil (or an oversize material) to transmit water through the pore structure of the fill material at a given rate. This property is indicative of the ability of a compacted fill material to provide drainage for excessive moisture. Corrosion Resistance – corrosion is a basic chemical or electro-chemical property of a material that can induce damage to concrete structures, steel piles, or metal appurtenances with which the embankment or fill material may come in contact.

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Table 24-9 provides a list of the standard test methods usually used to assess the suitability of conventional earthen fill materials for use in embankment or fill construction. Table 24-9. Embankment or fill material test procedures.

Property Test Method Reference
Gradation Particle Size Analysis of Soils ASTM D422
Sieve Analysis of Fine and Coarse Aggregate ASTM D136
Unit Weight and Specific Gravity Unit Weight and Voids in Aggregate ASTM D29
Specific Gravity of Soils ASTM D854
Relative Density of Cohesionless Soils ASTM D2049
Maximum Index Density of Soils Using a Vibratory Table ASTM D4253
Minimum Index Density of Soils and Calculation of Relative Density ASTM D4254
Moisture Densiity Characteristics Moisture-Density Relations of Soils and Soil-Aggregate Mixtures Using 5.5 lb (2.49 kg) Rammer and 12 in. (305 mm) Drop ASTM D698 (Standard)
Moisture-Density Relations of Soils and Soil-Aggregate Mixtures Using 10 lb (4.54 kg) Rammer and 18 in. (457 mm) Drop ASTM D1557 (Modified)
Compacted Density (In-Place Density) Density of Soil in Place by the Sand-Cone Method ASTM D1556
Density and Unit Weight of Soil in Place by the Rubber Balloon Method ASTM D2167
Density of Soil and Soil-Aggregate in Place by Nuclear Methods (Shallow-Depth) ASTM D2922
Density of Soil in Place by the Sleeve Method ASTM D4564
Shear Strength Unconsolidated Undrained Compressive Strength of Cohesive Soils in Triaxial Compression ASTM D2850
Direct Shear Test of Soils Under Consolidated Drained Conditions ASTM D3080
Consolidated-Undrained Triaxial Compression Test on Cohesive Soils ASTM D4767
Compressibility One-Dimensional Consolidation Properties of Soils ASTM D2435
One-Dimensional Consolidation Properties of Soils Using Controlled-Strain Loading ASTM D4186
One-Dimensional Swell or Settlement Potential of Cohesive Soils ASTM D4546
Bearing Capacity > California Bearing Ratio (CBR) of Laboratory-Compacted Soils ASTM D1883
Bearing Ratio of Soils in Place ASTM D4429
Permeability Permeability of Granular Soils by Constant Head ASTM D2434
Corrosion Resistance pH of Soil For Use in Corrosion Testing ASTM G51
Field Measurement of Soil Resistivity Using the Wenner Four-Electrode Method ASTM G57
Pore Water Extraction and Determination of the Soluble Salt Content of Soils by Refractometer ASTM D4542

REFERENCES FOR ADDITIONAL INFORMATION Nichols, Herbert L. Moving the Earth, McGraw-Hill Publishing Company, New York, New York, 1976.U.S. Bureau of Reclamation. Earth Manual. Washington, DC, 1991. | | : User Guidelines for Waste and Byproduct Materials in Pavement Construction

What is the most common natural problem found in embankments?

Highway Engineering Questions and Answers – Embankment and Subgrade This set of Highway Engineering Multiple Choice Questions & Answers (MCQs) focuses on “Embankment and Subgrade” 1. What is the last step in design of embankment? a) Height b) stability of slope c) Stability of foundation d) Settlement View Answer Answer: b Explanation: After the highway embankment construction, the stability of slope should be checked, settlement takes place after a few days and height is checked in design itself.

2. If the height of embankment increases _ a) Slope stability increases b) Slope stability remains constant c) Slope has to reduced d) Slopes need to be flattered View Answer

Answer: d Explanation: The slopes need to be flattered if the embankment height is increased, if the embankment height is small then slope may be kept constant.3. The fill material used in embankment is _ a) Peat b) Silt c) Clay d) Granular soils View Answer Answer: d Explanation: The granular soil with less plasticity are more preferable in filling material.4.

  • The settlement is due to _ a) More compaction b) Inadequate compaction c) Temperature d) Air pressure View Answer Answer: b Explanation: The settlement is due to the inadequate compaction effort which leads to excess settlement.5.
  • The stability of foundation is checked to ensure _ a) Lateral strength b) Compressive strength c) Shear strength d) Tensile strength View Answer Answer: c Explanation: The stability of the foundation is checked to ensure the soil satisfies the shear strength requirement.

Check this: | 6. Stability of slopes change with _ a) Climate b) Increase in load c) Increase in soil d) Increase in width of pavement View Answer Answer: b Explanation: The stability of slope mostly depends on the type of load if it changes the stability requirement will also change.7.

  1. An embankment is classified as high if height exceeds _ a) 3.0 m b) 4.0 m c) 5.0 m d) 6.0 m View Answer Answer: c Explanation: The embankment is classified as a high embankment if height exceeds 5.0m, if it is less than 5.0 m they may be medium height or small height embankments.8.
  2. What is the most common natural problem found in embankment? a) Settlement b) Stability of foundation c) Stability of slope d) Soil erosion View Answer Answer: d Explanation: All the problems are encountered by a highway engineer but soil erosion is a natural problem which cannot be avoided.9.
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The investigation of embankment should be carried out for _ a) Twice the height of embankment b) Thrice the height of embankment c) Exact height of embankment d) Half height of embankment View Answer Answer: a Explanation: The investigation of the embankment should be carried out at twice height of embankment below the ground level.10.

The consolidation can be achieved faster by _ a) Clay b) Peat c) Sand drains d) Sand filter View Answer Answer: c Explanation: The Sand drains are a type of drainage system which is used to accelerate the consolidation.11. What is the minimum spacing between the two sand beds? a) 1.0 m b) 1.5 m c) 2.0 m d) 2.5 m View Answer Answer: d Explanation: The minimum spacing between the two sand beds may be 2.5 m and the maximum is 6.0 m.12.

The liquid limit of soil for embankment construction is _ a) Less than 70% b) Less than 90% c) Less than 60% d) Less than 45% View Answer Answer: a Explanation: The minimum liquid limit should be less than 70% for embankment construction.13. The free swelling index of soil should be less than _ a) 50 b) 60 c) 70 d) 80 View Answer Answer: a Explanation: The free swelling index of the soil should be less than 50% for the soil for good embankment.14.

  1. The plasticity index for a sub grade should be less than _ a) 45 b) 35 c) 25 d) 15 View Answer Answer: c Explanation: The plasticity index for a sub grade should be less than 25 for embankment construction.15.
  2. The rollers that uses both tamping and kneading is _ a) Plain roller b) Vibratory roller c) Sheep foot roller d) Pneumatic roller View Answer Answer: c Explanation: The sheep foot roller can use both the procedure of tamping and kneading that is done by using a roller that resemble the paw of a sheep.

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What are the advantages and disadvantages of embankments?

Embankments – Raised banks along the river; they effectively make the river deeper so it can hold more water They are expensive and do not look natural but they do protect the land around them. Difference between embankments and levees:

An embankment can hold water and often supports a road or railroad. A levee is usually only used to prevent flooding.

Why Is The Construction Of Embankment Necessary The ” M ” on the bank is meant (embankment) to protect the land by holding more water. Why Is The Construction Of Embankment Necessary Embankments are projects designed to prevent flooding when river levels rise above normal bank height. The advantage is that a stretch of river can hold more water without flooding of adjacent land or property.

The disadvantages of embankments include the high cost of building them and their visual effect on the riverscape.Experience also shows that if an embankment fails, the subsequent flooding can happen very quickly, with less time for preparation than if flooding had occurred more gradually without an embankment in place.Clay is often used on the outside of embankments to make them impermiable to water, while sand is often used in the middle.

: Embankments – Raised banks along the river; they effectively make the river deeper so it can hold more water

How do embankments help prevent flooding?

Flood Embankments (levees): Like levees these increase the channel depth of a river, raising its bankfull discharge and reducing the risk of flood. Advantages: They increase the cross-sectional area of the river and therefore its hydraulic radius. This should reduce the risk of flooding.

How does embankment prevent soil erosion?

Embankments also provide protection to the surrounding area by holding back the water. Embankments constructed across canals make sure that the soil in the surrounding area doesn’t get affected. Building terraces is also another way to help prevent soil erosion.

What is the result of construction of embankments?

The construction of embankments leads to change in the natural course of river and therefore the river characteristics and flow conditions are bound to change. There are opposite views on the issue of construction of embankments as flood control measures.

What are the effects of embankments?

Over time embankments have created associated environmental degradation. Sea level rise is becoming prominent for the sedimentation on the other side. The ecology is changing into salinity intrusion water character for the changed river patterns.

What is the factor of safety of embankment?

Under Exhibit A2, Section A2c2, Stability of Embankments, it states that all embankment slopes designed and constructed within 200′ of a structure (bridge, retaining wall, culverts, etc.) shall have a minimum factor of safety of 1.5. Is this required for all pipe/box culverts? Please clarify the intent.

Asked at 10/22/2014 01:43:10 PM Yes, this includes all pipes and culverts. All embankments supporting structures require a minimum factor of safety of 1.5. To clarify the intent, the embankment within 200′ of any structure shall be searched slip circles and the design of the embankment shall result in a minimum factor of safety of 1.5 or greater for those slip circles that cut under any substructure or foundation.

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The embankment beyond those slip circles requiring a 1.5 factor of safety, shall have a minimum factor of safety of 1.3. Answered at 10/27/2014 10:17:05 AM

What is the advantage of embankment dam?

3. Foundation Condition – Earth dams are suited to the sites where a masonry dam cannot be used for structural reasons. These dams can be constructed even on compressible foundations. The intensity of foundation stress due to earth is less than that due to solid masonry.

What is the use of embankment dams?

Embankment dams are also used to retain lagoons of sedimented waste material from mining and industrial activities. From: Encyclopedia of Geology, 2005

What is embankment famous for?

Offering spectacular views of the London skyline and filled with stunning historic and modern tourist attractions, Embankment is one of those must see places! Embankment is perfectly placed for exploring world famous Buckingham Palace, the London Eye and the Houses of Parliament too, as its situated right on the northern bank of the River Thames inside the congestion charging zone.

  • The City of London, Westminster and Charing Cross surround Embankment, and South Bank is just across the river.
  • You’ll have no difficulty in getting around the rest of London either, as Embankment Tube Station, in tube Zone1, offers you an affordable and fast way to get around the capital.
  • You will also find tube stations like Westminster, Temple and Blackfriars really close by.

So, what are you waiting for? Come to Embankment today!

What are the advantages of earthen embankment?

Advantages of Earthen dam –

  1. It can simply be constructed with locally available material.
  2. The design of the dam is also quite easy so a variety of materials can be used to construct the dam.
  3. It is most economical because it is constructed with locally available materials.
  4. Any type of foundation is suitable for this dam.
  5. Where there is a wide layer of the valley it is suitable to construct.

How do construction of dams and embankments prevent flood?

BENIFITS OF DAMS – Main Content Dams provide a range of economic, environmental, and social benefits, including recreation, flood control, water supply, hydroelectric power, waste management, river navigation, and wildlife habitat.

    Recreation Dams provide prime recreational facilities throughout the United States. Boating, skiing, camping, picnic areas, and boat launch facilities are all supported by dams. Flood Control In addition to helping farmers, dams help prevent the loss of life and property caused by flooding. Flood control dams impound floodwaters and then either release them under control to the river below the dam or store or divert the water for other uses. For centuries, people have built dams to help control devastating floods. Water Storage Dams create reservoirs throughout the United States that supply water for many uses, including industrial, municipal, and agricultural. Irrigation Ten percent of American cropland is irrigated using water stored behind dams. Thousands of jobs are tied to producing crops grown with irrigated water. Mine Tailings There are more than 1,300 mine tailings impoundments in the United States that allow the mining and processing of coal and other vital minerals while protecting the environment. Electrical Generation The United States is one of the largest producers of hydropower in the world, second only to Canada. Dams produce over 103,800 megawatts of renewable electricity and meet 8 to 12 percent of the Nation’s power needs. Hydropower is considered clean because it does not contribute to global warming, air pollution, acid rain, or ozone depletion. Debris Control In some instances, dams provide enhanced environmental protection, such as the retention of hazardous materials and detrimental sedimentation.

    What is embankment in disaster management?

    Embankment is defined as a wall or bank of earth or stone built to prevent a river flooding an area.

    How do river embankments help in preservation of soil?

    Embankments should be constructed along river banks. Floods should be controlled so that the excess water does not cause much loss of soil Building. Building embankments along river banks can reduce the damage caused by and prevent flooding of fields.

    What are embankments used for?

    20.1 Introduction – Embankments are among the most ancient forms of civil engineering structures but are still among the most relevant ones. They are widely used, e.g. as embankment dams for reservoirs, as dikes for flood control along river banks and as road, railway and airport runway embankments in transportation.

    The requirements on performance of embankments depend mainly on their purposes. In hydraulic engineering and flood control, embankments are used to hold water back and for flood control respectively. Therefore, the seepage behavior is of primary importance. In road and railway construction, the settlements, particularly differential settlements of embankments are of major concern.

    In any case, the stability of embankments must be guaranteed since failure of embankments and dams can have serious consequences. Embankments may vary significantly in size (height and length). To date the tallest earth dam in the world, the Nurek Dam of Tajikistan in Central Asia, is about 300 m high, while most embankments along river banks and road/railway embankments are only a few meters above ground.

    • Whereas most embankment dams of reservoirs are only several hundred meters long, the river and road/railway embankments can reach lengths of hundreds of kilometres.
    • Despite the striking difference in size and length, however, some basic principles must be observed in design and construction of embankments.

    Based on the types of construction materials used, embankments are classified into several categories. These include reinforced embankment, earthfill embankment and rockfill embankment. In this chapter particular attention is given to those embankments which are used for the hydroelectric generation schemes, and irrigation and flood control works.