What Is Dynamic Compaction?
Dynamic compaction is a soil improvement technique. Dynamic compaction is a method used to increase the density of the soil when certain subsurface makes other methods inappropriate.
It is a method used to increase the density of soil deposits. The process involves dropping a heavyweight repeatedly on the ground at regularly spaced intervals.
Dynamic compaction is often used on new reclamations to compact the soil subsoil up to requirements to avoid liquefaction under an earthquake. It is a method that is used to increase soil deposits.
The process involves dropping a heavyweight repeatedly on the ground at regularly spaced intervals. The weight and height determine the amount of compaction that would occur.
Most soil types can be improved with dynamic compaction. Old fills and granular soils are most often treated. The soils below the water table have to be treated carefully to permit the emission of the excess pore water pressure created when the weight drops into the surface.
Dynamic Compaction
Deep Dynamic compaction is an efficient and cost soil improvement technique that uses dynamic effects to densify weak soil. The dynamic soil is generated by dropping statistics weight of 15 to 40 tons from a defined height of 10 to 30 meters.
This type of compaction is used to improve weak soil such as loose medium to coarse-grained sand with salt or clay content. It effectively enhances the soil of a depth of 10 meters, but it influences reach to 12 m depth.
It is utilized for settlement improvement of long-term liquefaction migration and improvement and performance, backfilling, landfilling, and sites are collapsing cavities.
Dynamic Compaction Process
Dynamic compaction is a method that is used to increase the density of the soil when certain subsurface contains make other methods inappropriate. It is a method that is used to increase the density of soil deposits. The process involves dropping a heavyweight repeatedly on the ground at regular space intervals.
- Heavy tamping is mainly used for deep compaction and involves dropping weight or pounder suspended from a crane onto the ground. The depth of treatment depends on soil types, the weight of the pounder in tonnes, and the drop height in meters.
- The weight used in the process of this type of compaction depends on the degree of compaction desired and is between 8 tonnes to 36 tonnes. The height varies from 1m to 30m.
- The impact of free fall creates stress waves that help densify the soil. These stress waves can penetrate up to 10m.
- In soil, these waves create liquefaction that follows by the compaction of the soil and in cohesive soil, they create an increased amount of pour water pressure that is followed by compaction of soil, they create an increased amount of pore water pressure that is followed by the compaction of the soil.
- Pore water pressure is the pressure of water trapped with particles of rock and soil.
- This method uses a cycle duty crane to drop the weight. Although specially built rings have been constructed. The crane is typically rigged with a sufficient boom to the drop weight from the height of 15.4 to 30.8 m ( 50 to100ft)
- With a single line to alone the weight to nearly “free fall,” maximizing the energy of height strikes the ground.
- The compaction of the underground is initiated by vibration, which leads to the rearrangements of the particles. These vibrations are generated from the impact of weight on the surface.
Dynamic Compaction Equipment
The various types of Dynamic compactors used in building projects include:
- Vibratory Plate Compactor
- Smooth Wheeled Rollers
- Sheepsfoot Rollers
- Rammers
- Pneumatic Roller
Types of Dynamic Compaction Process
- Dynamic Compaction Method
- Rapid Impact Compaction (RIC)
- High Energy compaction
The industrial application of dynamic simulation was limited decades ago; however, with the development in computing science and the improvement of computer processor speeds, those limitations have been overcome now by incorporating a high level of detail in modeling, and we can also fairly large models.
Some applications areas of these technologies are
- Process design
- Process evaluation and DE-bottlenecking
- Safety analysis
- Distribution and gathering systems
1. Process Design
It is a task that can be performed using the dynamics simulations since dynamic models are considered to hold up, equipment size is required for running simulations in the case of a new design, and initial sizing can be obtained utilizing a study state stimulation.
2. Process Evaluation and De-Bottle Necking
Process evaluation is a bottleneck that involves performance evaluation of an existing piece of equipment of all facilities running under process conditions different from the design cases.
3. Safety Analysis
Safety analysis if can be easily run with dynamic models such as distillation column overpressure heat exchanger pipe ruptures, valve leakage pipe ruptures, evolve leakage pump failure indicator drift, and many others.
4. Distribution and Gathering System
Distribution and gathering system piping network controlled design facilities can also be carried out due to the nature of the pressure-driven solution typically implemented in dynamics stimulators which allows an accurate representation.
5. Relife and Blowdown System
A relief and blowdown system is a specific application where dynamic simulation can improve the design. The Blowdown pressure safety valve may be oversized if API521 is applied.
Purpose of Dynamic Compaction
The purpose of using Dynamic compaction is as follows
- The purpose of this type of compaction technique is to transmit high energy waves throw a compressible soil layer to improve the geotechnical properties of soil at greater depths.
- It is repeated on a grid pattern across a site. The spacing of the grid pattern is determined based on underground conditions using a foundation.
- The resulting high energy impact transmitted shock waves through the ground to the depth to be treated.
- This reduces air and water voids between soil particles resulting in enforced settlement.
- This type of compaction is used for liquefaction mitigation in areas where loose saturated granular soil occurs up to 12 meters.
- This type of compaction is often used on new reclamations to compact subsoil up to requirements to avoid liquefaction under an earthquake. Applying dynamic compaction will result in soil densification due to vibration and reorganization friction angle increase.
- This type of compaction is a technique that identifies loose granular materials at a depth of 10 to 12 meters below the surface by repeatedly dropping a pounder to10 to20 tons from a height of 10 to 25 m to the surface.
- Applying dynamic compaction will result in the following effects:-
- Soil densification is due to vibration and particle reorganization.
- Friction angle increase.
- Stiffness increase.
- Liquefaction mitigation.
- Limitation of settlement when applying load.
Applications of Dynamic Compaction
There are various applications of Dynamic Compaction that are as follows
- FOR EXAMPLE, the DC technique is used for the compaction of embankments for roads, railways, runways, and aprons for airports and port areas.
- In this case, the compaction can be related to liquefaction mitigation and improving the load settlements.
- DC is often used to compact reclamations up to specification.
- DC can be used to compact ways for the heavy mining trucks to allow for higher production in the filling of spoils. Dynamic compaction is used in the construction industry to compact terrains.
- It also treats industrial warehouses, port and airport platforms, roads and railways embankments, and heavy storage tanks.
Advantages of Dynamic Compaction
There are various advantages of dynamic compaction that are as follows
- Densify and compact soil to a depth of 12 meters.
- Effective in various soil conditions.
- Cost-effective.
- Dramatic cost saving above deep foundation and most undercut and replace options.
- Accelerate schedules.
- Mitigate soil liquefaction.
- Improves the bearing capacity of the soil.
- Decrease the volume of landfill waste.
- Refuses post constructions settlements
- Environmentally friendly.
Disadvantages of Dynamic Compaction
There are also some disadvantages of Dynamic compaction that are as follows.
- It cannot be used within 30m from buildings and 15m from underground services.
- Dynamic comparison is not appropriate if the water depth is less than 1.5m.
- It cannot be applied to soft cohesive soils located in the upper part of the compaction.
- This type of compaction is not effective when soils have file content over 20%.
- Requires intensive in situ testing program testing to examine the results.
Frequently Asked Questions (FAQ)
What Are the Types of Dynamic Compaction?
Common dynamic compaction techniques include:
- Dynamic Compaction Method
- Rapid Impact Compaction (RIC)
- High Energy compaction
Dynamic Compaction Cost
Depending on the size of the project, the dynamic compaction cost can vary from $ 1 to more than $ 2 per square foot. Dynamic compaction designs can vary from $ 20,000 to $ 40,000 depending on the complexity of the project.
What Is Number of Passes in Dynamic Compaction?
Deep soil level treatment usually requires two and five passes with a pass for the first high treatment.
What Factors Influence Dynamic Compaction?
The effectiveness of dynamic compaction is dependent on the combination of weight,number of drops, height of drop, geometry of pounder, spacing, , and total compactive energy applied.
What Is the Purpose of Dynamic Compaction?
Dynamic compaction is used for ground improvement. This method solidifies the soil and fills the material using drop weight. It involves frequent surface tamping with the ground using heavy steel and concrete weights.
What Are the Merits and Demerits of Dynamic Compaction?
There are various Merits of dynamic compaction that are as follows
- Densify and compact soil to a depth of 12 meters.
- Effective in various soil conditions.
- Cost-effective.
- Dramatic cost saving above deep foundation and most undercut and replace options.
- Accelerate schedules.
- Mitigate soil liquefaction.
- Improves the bearing capacity of the soil.
- Decrease the volume of landfill waste.
- Refuses post constructions settlements
- Environmentally friendly.
There are also some Demerits of Dynamic compaction that are as follows
- It cannot be used within 30m from buildings and 15m from underground services.
- Dynamic comparison is not appropriate if the water depth is less than 1.5m.
- It cannot be applied to soft cohesive soils located in the upper part of the compaction.
- Dynamic compaction is not effective when soils have file content over 20%.
- Requires intensive in situ testing program testing to examine the results.
Deep Dynamic compaction
Deep Dynamic compaction is a technique that identifies loose granular materials into the depth of 10 to 12 meters below the surface by repeatedly dropping a pounder to10 to20 tons from a height of 10 to 25 m to the surface.
Who Invented Dynamic Compaction?
Louis Menard invented the Dynamic Compaction technique in 1960.
What Are the Various Dynamic Compactors Used?
The various types of Dynamic compactors used in building projects include:
- Vibratory Plate Dynamic Compactor
- Smooth Wheeled Rollers
- Sheepsfoot Rollers
- Rammers
- Pneumatic Roller
- Vibratory Roller
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