Deep Dynamic Compaction Deep Dynamic Compaction 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.
What is dynamic compaction and how does it work?
Dynamic compaction is a ground improvement technique that densifies soils and fill materials by using a drop weight. The drop weight, typically steel, is lifted by a crane and repeatedly dropped onto the ground surface.
What type of soil can be improved with dynamic compaction?
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 emission of the excess pore water pressure that is created when the weight is dropped onto the surface.
How do you find the maximum effective depth of compaction?
The maximum effective depth of compaction using dynamic compaction can be determined by using the formula as follows: (2.1) D max = n WH 1 / 2 where W is the dropped weight in tonnes, H is the height of drop in metres and the value n is a factor that depends upon the type of soil.
What are the advantages and disadvantages of different compaction methods?
Each of the three compaction methods has its own advantages and disadvantages depending on the site and soil condition in the various areas. The dynamic compaction method produces a relatively more uniform degree of densification in each layer. However, the depth of densification is limited to 6 or 7 m.
What is deep compaction?
Deep soil compaction as a method of ground improvement and to stabilization of wastes and slopes with danger of liquefaction, determining the modulus of deformation and shear strength parameters of loose rock. Waste Manag.
What is the purpose of dynamic compaction?
Dynamic compaction is a method that is used to increase the density of the soil when certain subsurface constraints make other methods inappropriate. It is a method that is used to increase the density of soil deposits. The process involves dropping a heavy weight repeatedly on the ground at regularly spaced intervals.
What are different types of dynamic compaction methods?
Common dynamic compaction techniques include: the Dynamic Compaction (or Heavy Tamping) method, the Rapid Impact Compaction (RIC), and. the High Energy Impact Compaction (HEIC) techniques.
Which soil is suitable for dynamic compaction?
coarse grained sandThe dynamic compaction is used to improve weak soil such as loose medium to coarse grained sand with salt or clay content.
What are the deep compaction techniques?
Articles > Deep Compaction Techniques Heavy tamping. Vibration. Compaction grouting. Vibro-compaction and vibro-replacement.
What is the difference between static and dynamic compaction?
Static compaction gives higher value in density of soil and CBR values. The static compaction onto Soil A specimen has given the value of MDD= 1.86 Mg/m3, and the CBR value was 22.62%. 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 shallow compaction?
Surface or shallow compaction is one of the earliest, cheapest and commonly used techniques to improve the physical and mechanical properties of loose soil specially for imported structural fill. It is simply rearranging of soil particles to reduce air ratios using surface static or vibrating mechanical effort.
What is explosive compaction?
Explosive Compaction (EC) is the ground modification technique whereby the energy released from setting off explosives in subsoil inducing artificial earthquake effects, which compact the soil layers.
What are the advantages of the compaction of soils?
Compaction of the soil and removing air voids generally increases the soil's sheer strength, decreases its compressibility, and decreases its permeability. It will reduce the voids ratio making it more difficult for water to flow through soil.
What are the various dynamic compaction equipment used?
The various types of compaction equipment used in building projects include: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:
Why is compaction done in layers?
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 mean by 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 are the advantages of the compaction of soils?
Compaction of the soil and removing air voids generally increases the soil's sheer strength, decreases its compressibility, and decreases its permeability. It will reduce the voids ratio making it more difficult for water to flow through soil.
Why is compaction done in layers?
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 are the various dynamic compaction equipment used?
The various types of compaction equipment used in building projects include: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 is dynamic consolidation?
Dynamic consolidation involves soil compaction by means of multiple drops of a heavy weight from a large height. This technique is particularly applicable to loose granular soils located near the ground surface.
What is dynamic compaction?
Dynamic compaction uses the energy from a falling weight in a pre-determined grid pattern to improve granular soils and fills.
What are the advantages of granular soil?
Advantages. Capable of compacting a wide variety of weak soils. Treated granular soils and fills have increased density, friction angle, and stiffness. Can improve soil conditions on marginal sites to extent that shallow foundations can be used without deep excavation or piling.
What is dynamic compaction?
Dynamic compaction is an efficient and cost-effective soil improvement technique that uses the dynamic effect of high energy impacts to densify weak soil. The dynamic effect is generated by dropping a static weight (15-40 tones) from a defined height (10-30 m).
When is dynamic compaction not effective?
Dynamic compaction is not effective when soils have fines content in excess of 20%.
How far away from buildings can you use Dynamic Compaction?
It cannot be used within 30m from buildings and 15m from underground services. Dynamic compaction is not appropriate if water depth is less than 1.5m. It cannot be applied if soft cohesive soils are located in the upper part of the compaction.
How does high energy impact affect soil?
The resulting high energy impact transmits shock waves through the ground to the depth to be treated. This reduces air and water voids between soil particles resulting in enforced settlement.
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.
How much does 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 heavy tamping?
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.
How much weight is used in dynamic compaction?
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.
What is DC technique?
The DC technique is for example used for the compaction of embankments for roads, railways, runways, and aprons for airports and port areas.
When is dynamic compaction not effective?
Dynamic compaction is not effective when soils have files content over 20%.
How deep does a soil compact?
Densify and compact soil to a depth of 12 meters.
What is dynamic compaction?
Jump to navigation Jump to search. Dynamic compaction is a method that is used to increase the density of the soil when certain subsurface constraints make other methods inappropriate. It is a method that is used to increase the density of soil deposits. The process involves dropping a heavy weight repeatedly ...
What is the process of dropping a heavy weight repeatedly on the ground at regularly spaced intervals?
It is a method that is used to increase the density of soil deposits. The process involves dropping a heavy weight repeatedly on the ground at regularly spaced intervals. The weight and the height determine the amount of compaction that would occur.
What is the pressure of water that is trapped within the particles of rocks and soils?
Pore water pressure is the pressure of water that is trapped within the particles of rocks and soils. The degree of compaction depends on the weight of the hammer, the height from which the hammer is dropped, and the spacing of the locations at which the hammer is dropped.
Can soil be improved with dynamic compaction?
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 emission of the excess pore water pressure that is created when the weight is dropped onto the surface.
What is dynamic compaction?
Dynamic Compaction method is used to improve problematic soils by increasing bearing capacity, reducing settlement of the foundation and reducing liquefaction potential for residential and office buildings, reservoirs, highways, railways, airports and ports.
When was the Dynamic Compaction Method first used?
The first application of Dynamic Compaction method in Iran was reported in late 1973 for the purpose of ground improvement in the Shahriar region in the southwest of Tehran. The use of Dynamic Compaction ground improvement method has been considered especially in the seventies and simultaneously with the expansion of large development projects in the south of the country.
What is DC in soil?
Dynamic Compaction (DC) is one of the ground improvement methods that increases the soil compaction by throwing a steel or concrete weight. The weights usually weigh 5 to 40 tons and are released from a height of 10 to 40 m. These weights are thrown on the ground with a special pattern according to the executive plans.
When was DC invented?
Throwing weights on the ground is a very old method, to the extent that some attribute the concept of DC to the time of the Roman Empire. However, studies of Dynamic Compaction (DC) in the literal sense were first conducted in 1957 by the British Road Research Laboratory, and in 1970 the French engineer L. Menard introduced this method with a patent. An article published by Menard and Brevis (1975) provided the theoretical basis for the consolidation of fine-grained soils by heavy compaction. Dynamic Compaction method was developed in 1973 in England and in 1975 in the United States.
How many stages are repeated in compacting?
Stages 4 to 7 are repeated until the compacting points are completed for the first time.
What is the most important factor in depth of improvement?
The applied energy of each impact (W.H) is the most important factor in the depth of improvement. Various studies have been performed on the relationship between energy and depth of improvement and relations have been presented. Among the proposed relations, the Menard empirical relation is more common among engineers:
What type of soil has large air cavities?
Soils that have large air cavities (such as buried garbage and ground filled with poor soil)
What is dynamic compaction and why do we use it?
Since the late 60s, the Menard group has applied this technique to thousands of sites for very different types of structures and conditions (port and airport platforms, heavy storage, buildings, landfills…) to reduce settlement, mitigate liquefaction, stabilize or treat hydraulic fill, limit lateral earth pressure behind quay walls, etc. The dynamic compaction technique achieves deep ground densification using the dynamic effects of high energy impacts resulting from the drop of large pounders.
Can we use dynamic compaction close to structures?
There are structures 20 meters from your worksite; can we use dynamic compaction?
What are the disadvantages of deep dynamic compaction?
Some disadvantages include the relatively shallow effective depths of improvement (typically 30 to 35ft) and the potential to damage nearby buildings and infrastructure with the large ground vibrations. The following video contains some great information regarding deep dynamic compaction:
What are the advantages of deep soil mixing?
Some advantages of deep soil mixing include low noise problems, high production rates, avoidance of dewatering.
How deep is DDC?
The maximum depth of improvement is typically around 70ft to 100ft with the maximum densification occurring at around 1/2 of the effective depth. DDC is most suitable for saturated sands and silty sands though improvements can still be made on certain fine grained soils if they are located above the groundwater table.
How deep is the best depth for ground improvement?
The impact of the weight on the ground creates low frequency energy waves which move and shake the soil causing compression and densification. The maximum depth of improvement is typically around 70ft to 100ft with the maximum densification occurring at around 1/2 of the effective depth.
What is DDC in soil?
DDC can also help with collapsible soils or soil strata that have large void spaces (like Karst). Liquefaction potential of soils is also reduced when deep dynamic compaction is employed. This method has several advantages in that it is a low cost way to improve soil properties.
How does cementicious grout work?
With this method of ground improvement a very fluid, cementicious grout is pumped into the ground under high pressure. The high pressure forces the grout to fill the void spaces in granular materials resulting in higher density soils, improved strength and stiffness and a lower hydraulic conductivity.
What is used to mix soil?
When deep soil mixing is used, a drill rig with one or multiple counter rotating augers drills down into the ground to mix the soil with additives. Typically grout, lime, flyash, or even some other additives such as montmorillinite clay are added to the soil during the mixing process to improve strength and stiffness.
Purpose
Dynamic Compaction Process
- The concept of Dynamic compaction is simple but experienced engineers and good planning is essential. Dynamic compaction process includes lifting and dropping a heavy weight several times in one place. It is repeated on a grid pattern across the site. The spacing of grid patterns is determined based on underground condition, foundation loading, and...
Advantages
- 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
Disadvantages
- It cannot be used within 30m from buildings and 15m from underground services.
- Dynamic compaction is not appropriate if water depth is less than 1.5m.
- It cannot be applied if soft cohesive soils are located in the upper part of the compaction.
- Dynamic compaction is not effective when soils have fines content in excess of 20%.
Applications
- Densification of weak soil; fills, mine refuse, collapsible soils, sanitary landfills, and soils loosened by sinkholes.
- Reclamation projects.
- Treatment of industrial warehouses, port and airport platforms, roads and railways embankments, heavy storage tanks.
What Is Dynamic Compaction?
- Dynamic compactionis 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 compactionis often used on new reclamations to compact the soil subsoil u…
Dynamic Compaction
- Deep Dynamic compactionis 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 ofcompactionis used to improve weak soil such as loose medium to coarse-grained sand with salt or ...
Dynamic Compaction Process
- Dynamic compactionis 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. 1. Heavy tamping is mainly used for deep compaction and inv…
Dynamic Compaction Equipment
- The various types of Dynamic compactorsused in building projects include: 1. Vibratory Plate Compactor 2. Smooth Wheeled Rollers 3. Sheepsfoot Rollers 4. Rammers 5. Pneumatic Roller
Types of Dynamic Compaction Process
- Dynamic Compaction Method
- Rapid Impact Compaction (RIC)
- High Energy compaction
Purpose of Dynamic Compaction
- The purpose of using Dynamic compaction is as follows 1. The purpose of this type ofcompactiontechnique is to transmit high energy waves throw a compressible soil layer to improve the geotechnical properties of soil at greater depths. 2. It is repeated on a grid pattern across a site. The spacing of the grid pattern is determined based on underground conditions us…
Applications of Dynamic Compaction
- There are various applications of Dynamic Compaction that are as follows 1. FOR EXAMPLE, the DC technique is used for the compaction of embankments for roads, railways, runways, and aprons for airports and port areas. 2. In this case, the compaction can be related to liquefaction mitigation and improving the load settlements. 3. DC is often used to compact reclamations up t…
Advantages of Dynamic Compaction
- There are various advantages of dynamic compactionthat are as follows 1. Densify and compact soil to a depth of 12 meters. 2. Effective in various soil conditions. 3. Cost-effective. 4. Dramatic cost saving above deep foundation and most undercut and replace options. 5. Accelerate schedules. 6. Mitigate soil liquefaction. 7. Improves the bearing capacity of the soil. 8. Decrease …
Disadvantages of Dynamic Compaction
- There are also some disadvantages of Dynamic compactionthat are as follows. 1. It cannot be used within 30m from buildings and 15m from underground services. 2. Dynamic comparison is not appropriate if the water depth is less than 1.5m. 3. It cannot be applied to soft cohesive soils located in the upper part of the compaction. 4. This type of compaction is not effective when soi…