What is deep dynamic compaction

Dynamic compaction (DC), also known as dynamic deep compaction, was advanced in the mid-1960s by Louis Menard. The process involves dropping a heavy weight on the surface of the ground to compact soils to depths as great as 12.5 m.

What is meant by dynamic compaction?

Dynamic compaction is a ground improvement technique that densifies soils and fill materials by using a drop weight. The ground is subjected to repeated surface tamping using a heavy steel and concrete weight. Typically the tamper weighs between 10 and 12 tonnes, dropping in free fall from heights of up to 10 metres.

What is the difference between static and dynamic compaction?

Answer: Static compaction gives higher value in density of soil and CBR values. … Whereas, the dynamic compaction applied onto Soil A specimen has given the value of MDD= 1.74 Mg/m3, and the CBR value was 20.14%.

What is deep compaction?

Deep Compaction and Objectives Compaction. ➢Deep compaction techniques are required when. in–situ soil extending to large depths does not meet. the requirements of performance criteria specified for the expected loading and environmental conditions.

How much does dynamic compaction cost?

Depending on the number of passes, grid dimensions and size of the project, cost can vary from $1 per square foot to more than $2 per square foot. The design of a dynamic compaction program may vary from $20,000 to $40,000 depending on the complexity of the project.

Which soil is suitable for dynamic compaction?

Dynamic compaction is suitable for densification of loose sand deposits such as those typically occurring in coastal, glacial, and alluvial deposits, as well as for dredged or hydraulically placed fills.

How does deep dynamic compaction densify granular soils?

Dynamic compaction is a technique used for in-situ densification of granular soil deposits by heavy impact. This technique primarily involves dropping a heavy weight repeatedly on the ground surface at a regular grid of impact points.

Which of the following is a deep compaction technique?

Articles > Deep Compaction Techniques Heavy tamping. Vibration. Compaction grouting. Vibro-compaction and vibro-replacement.

What is deep compaction of soil?

Dynamic compaction is a ground improvement technique that uses a drop weight to densify loose soils. Soil densification is carried out by the repeated, controlled impact of a heavy weight (10-40 tons) on the ground surface. Vibrations are generated for a considerable lateral distance.

What is shallow compaction?

Shallow Compaction: … The semi-static weight and/or vibratory action of the equipment compacts the unconsolidated soils to a specified level of compaction determined by a geotechnical engineer and suitable for supporting the proposed loads.

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What is kneading compaction?

Manipulation,also sometimes referred to as kneading,acts to compress materials at a greater depth. It does so by reducing the surface area at each particular point of compaction. This enables the compactor to exert a more localized – and hence greater – amount of force in each particular area.

How deep does a plate compactor compact?

A rule of thumb is that a compactor will compact 1 inch of material for every 1,000 pounds of compaction force it exerts.

What is static compaction?

A static compaction method is described to determine equivalent static pressure equivalent to the standard, reduced standard and the reduced modified Proctor test. The relationship between water content and dry unit weight corresponding to different static pressure is found to be parabolic in nature.

What is heavy tamping?

Heavy tamping is a deep dynamic compaction technique and has been increasingly used since the beginning of the 1970s. The present paper reports on in situ measurements and theoretical investigations referring to the decay of free soil vibrations caused by the falling weight after each impact.

What are the merits and demerits of dynamic compaction?

• Compacts large areas of loose granular fills.
• Reduces the volume of landfill waste.
• Increases in situ density and the voids are collapsed.
• Increased bearing capacity.
• Reduces post-construction settlements.

What is the maximum depth conventional compaction can densify?

The stone columns are typically spaced 1.5–4.0 m apart and can densify soil to a depth of 4–15 m, but soils as deep as 30 m have been treated using this method.

What are the various dynamic compaction equipment used?

• Smooth Wheeled Rollers: It is an important equipment for compaction. …
• Sheepsfoot Rollers: Sheepsfoot rollers also known as a tamping roller. …
• Pneumatic Roller: …
• Vibratory Roller: …
• Rammers: …
• Vibratory Plate Compactor:

What are the types of compaction?

The method of compaction is primarily of four types such as kneading, static, dynamic or impact and vibratory compaction.

What is dynamic replacement?

Dynamic Replacement (DR) is the variation of Dynamic Compaction, and consists in delivering impact energy to the ground by means of dropping a large mass from a significant height.

What is number of passes in dynamic compaction?

Between two and five passes are generally required, with the first or earlier high energy treatment passes aimed at treating the deeper soil layer.

What are the merits of dynamic compaction technique?

• Densify and compact soil to a depth of 12m.
• Effective in various soil conditions.
• Cost effective.
• Dramatic cost savings in excess of deep foundations and most undercut and replace options.
• Accelerate schedules.
• Mitigate soil liquefaction.
• Improves bearing capacity of soil.
• Decreases the volume of landfill waste.

What is meant by reinforced soil?

Reinforced soil or mechanically stabilized soil consists of soil that is strengthened by tensile elements such as metal strips, geotextiles, or geogrids. The development of polymeric materials in the form of geosynthetics has brought major changes in geotechnical engineering.

What is dynamic consolidation?

Dynamic consolidation is a method of compacting soil deposits using a falling weight. It is used to speed up expected soil-settlement at an thus increase the load-bearing capacity of the soil without the use of extra back filing and settlement time.

What is rapid impact compaction?

Rapid Impact Compaction (RIC) is a technique unique to BBGE in the UK, used for treating granular fills up to 3-4 metres in depth. BASIC TECHNIQUE. RIC utilises a 7 tonne hydraulic piling hammer repeatedly hitting a heavy 1-1.5m diameter steel foot.

What is soil compaction?

What is compaction? Soil compaction occurs when soil particles are pressed together, reducing pore space between them (Figure 1). Heavily compacted soils contain few large pores, less total pore volume and, consequently, a greater density. A compacted soil has a reduced rate of both water infiltration and drainage.

What are the main functions of columns in ground installed by deep replacement methods?

Columns are mostly used to improve soft soils by increasing the bearing capacity, reducing total and differential settlements, accelerating consolidation and enhancing stability.

Why should we use mechanical compacting?

Soil compaction is the practice of applying mechanical compactive effort to densify a soil by reducing the void space between soil particles. Compaction occurs when particles are pressed together to reduce the space between them. Highly compacted soils contain very few spaces resulting in soil with higher unit weight.

What is smooth wheel roller?

Smooth-wheel rollers, as the name implies, use one large, smooth steel drum in the front and either one or two wheels on the rear end for compaction. These are either tandem (two-wheel) or three-wheel rollers. Smooth wheel rollers are ideal for gravel, sand, ballast, and surface dressings.

What is compaction grouting?

Compaction grouting involves the injection of a low slump, mortar grout to densify loose, granular soils and stabilise subsurface voids or sinkholes.

What is compaction pressure?

Compaction pressure highly influences the pore size as well as number of pores. With increase in compaction pressure the surface contact area of the powder particles increase which reduce the porosity. The maximum valve of the density and hardness is obtained for 700 MPa and 3 min dwell time.

What is pneumatic tyred roller?

Pneumatic tyred roller. This type of roller consists of a heavily loaded wagon with several rows of four to six closely spaced tyres. This is also called rubber tyred roller. It provided uniform pressure throughout the width.