What is the purpose of compaction test?
What is the purpose of the compaction test? The test aims to establish the maximum dry density that may be attained for a given soil with a standard amount of compaction effort. When a series of soil samples are compacted at different water content, the plot usually shows a peak.
What is compaction in geotechnical engineering?
Compaction refers to the densification of shallow soil layers by rollers. Dynamic compaction refers to dropping large weights from a given height onto the ground surface. It consists of lifting a heavy weight of mass and dropping it from a preset height so as to pound the soil and compact it in the process.
Why is compaction important?
Compaction is the application of mechanical energy to a soil to rearrange the particles and reduce the void ratio. The principal reason for compacting soil is to reduce subsequent settlement under working loads. Compaction can prevent the build up of large water pressures that cause soil to liquefy during earthquakes.
What is meant by compaction test?
A laboratory compacting procedure to determine the optimum water content at which a soil can be compacted so as to yield the maximum density (dry unit weight). The maximum dry density for a given compactive effort will usually produce a sample whose saturated strength is near maximum. …
How many types of compaction tests are there?
The most commonly used laboratory test is called the Proctor compaction test and there are two different methods in obtaining the maximum density. They are the standard Proctor and modified Proctor tests; the modified Proctor is more commonly used.
How is a compaction test done?
The soil is usually compacted into the mold to a certain amount of equal layers, each receiving a number of blows from a standard weighted hammer at a specified height. This process is then repeated for various moisture contents and the dry densities are determined for each.
How do you get compaction?
3.7 Calculate percent relative compaction by dividing the dry density of the material from the test site by that material’s moisture density relation curve’s maximum dry density, and multiply by 100%.
What are the method of compaction?
The method of compaction is primarily of four types such as kneading, static, dynamic or impact and vibratory compaction. Different type of action is effective in different type of soils such as for cohesive soils; sheepsfoot rollers or pneumatic rollers provide the kneading action.
What does it mean by 95% compaction?
95% compaction means that the soil on the construction site has been compacted to 95% of the maximum density achieved in the lab. It means that when you conduct compaction test(in the laboratory) on a small soil sample of a particular site. You get some value of maximum dry unit weight at certain moisture content.
How do I get 95 compaction?
The difference between the Standard and Modified Proctor tests is the amount of energy used to compact the sample. 95% compaction requires the soil placed as engineered fill to have a density of at least 95% of the maximum laboratory density as determined by the method specified in the project specifications.
How is compaction of soil used in geotechnical engineering?
Home/ Geotechnical Engineering / Compaction of Soil – Test Methods of Soil Compaction and their Uses. Compaction of soil is the pressing of soil particles close to each other by mechanical methods. Air during compaction of soil is expelled from the void space in the soil mass and therefore the mass density is increased.
What are the results of a soil compaction test?
Within the framework of engineering applications, compaction is particularly useful as it results in: 1 An increase in strength of soils 2 A decrease in compressibility of soils 3 A decrease in permeability of soils
What’s the procedure for the Proctor compaction test?
Test Procedure. The procedure of the Proctor Compaction Test consists of the following steps: Obtain about 3 kg of soil. Pass the soil through the No. 4 sieve. Weight the soil mass and the mold without the collar (W m ). Place the soil in the mixer and gradually add water to reach the desired moisture content (w).
How does compaction of soil help prevent earthquakes?
Compaction can prevent the build up of large water pressures that cause soil to liquefy during earthquakes. Reduction in soil swelling (expansion) and collapse (soil contraction).