What Is Dynamic Compaction?
Dynamic compaction is a method that is used to increase the density of the soil when certain subsurface makes 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 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 that are below the water table have to be treated carefully to permit the emission of the excess pore water pressure that is created when the weight dropped into the surface.
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.
The dynamic 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. not only does it utilized for settlement improvement of long-term liquefaction migration but also improvement and performance, backfilling, landfilling, sites are collapsing cavities.
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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.
- The heavy tamping is mainly used for deep compaction and involves dropping weight or pounder that is 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 that is used in the process of Dynamic 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 in the densification of 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 that is trapped with particles of rock and soil.
- This method is done by using 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
- 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 in incorporate 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 by using the dynamics simulations in the since dynamic models are considered to hold up, equipment size is required for running simulations in the case of new design an 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 what 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 steady design facilities can be also carried out due to the nature of the pressure-driven solve typically implemented in dynamics stimulator which allows an accurate representation.
5. Relife and Blowdown System
Relief and blowdown system a specific application where dynamic simulation can improve the design. 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 the dynamic 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 uses 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.
- Dynamic compaction is used for liquefaction mitigation in areas where loose saturated granular soil occurs up to the depth of 12 meters.
- Dynamic 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 the following effects Soil densification due to vibration and reorganization friction angle increase.
- 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.
- Applying dynamic compaction will result in the following effects:-
- Soil densification 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
- The DC technique is for example used for the compaction of embankments for roads, railways, runways, and aprons for airports and port areas.
- The compaction can this case be related to liquefaction mitigation but also to improve to 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 are to allow for higher production in the filling of spoils. Dynamic compaction is used in the construction industry to compact terrains.
- It is also used for the Treatment of industrial warehouses, port and airport platforms, roads and railways embankments, 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.
- 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.
Also Read: What Is Standard Proctor Test? | Uses of Standard Proctor Test | Standard Proctor Compaction Test Apparatus | Procedure of Standard Proctor Test | Advantages & Disadvantages of Standard Proctor Test
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 soft cohesive soils are located in the upper part of the compaction.
- Dynamic compaction is not effective when soils have files content over 20%.
- Requires intensive in situ testing program testing to examine the results.