Compaction properties of different soils and suitable solutions - Civil Rack (2023)

FAQs

What are the different types of compaction of soil? ›

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

"The soils easiest to compact are soils with spheric and smooth particles," he continues. "Soils with irregular particles are more difficult to compact but, on the other hand, they have a larger bearing capacity."

Experimental studies have shown that the soil compaction results in increase in the soil strength, bulk density, volumetric water contents, and field capacity while decrease in total porosity, soil aeration, water infiltration rate, and saturated hydraulic conductivity.

Compaction reduces the voids present in the soil hence permeability also reduces. At a particular density, for the same soil sample, permeability is more for soils which are compacted to dry of optimum than those compacted to wet of optimum.

Soil compaction is the process whereby soil is mechanically compressed through a reduction in the air voids. It is measured in terms of the dry density or amount of solid matter in unit volume. Soils range in dry density from about 140 lb. per cubic foot for coarse-grained gravels and sands to about 90 lb.

95 percent compaction means that the soil has been compacted to 95 percent of the possible density of the soil through compactive efforts. Maximum dry density, along with optimum moisture content, is determined in the laboratory and provides the target for field compaction.

Clayey and silty soils are most susceptible to compaction because their particles hold more water for longer than sands or loams. As a result, clay soils remain in a plastic state, sometimes for the whole year, which means they will compress and shear when a load is applied to them.

What is the acceptable percentage of compaction? ›

In general, a compaction between 80 and 85 percent of the standard Proctor maximum dry density optimizes slope stability with vegetation development and growth.

The following practical techniques have emerged on how to avoid, delay or prevent soil compaction: (a) reducing pressure on soil either by decreasing axle load and/or increasing the contact area of wheels with the soil; (b) working soil and allowing grazing at optimal soil moisture; (c) reducing the number of passes by ...

The primary goal of compacting a soil is to enhance certain desirable properties such as compressibility, water absorption, and permeability, as well as increase soil strength, bearing capacity, and change in swelling and shrinkage characteristics.

Soil physical properties include texture, structure, density, porosity, consistence, temperature, and color.

The most direct effect of soil compaction is an increase in the bulk density of soil.

The most important point on the compaction curve is the optimum compaction point in which two important parameters, maximum dry unit weight ( dmax) and optimum water content (wopt), are obtained, and they represent compaction behaviour (Figure 1).

Scientists attribute soil formation to the following factors: Parent material, climate, biota (organisms), topography and time.

95% compaction is just 95% of the Proctor density, whereas 98% compaction is 98% of the Proctor density. If the Proctor density is 100 (let's ignore units here), and the percent compaction is 95, that means that the soil that was just packed has a density of 95.

Compaction Using Drop Hammer Methods Drop hammer methods are the test methods most commonly used for establishing the compaction characteristics of soils and aggregates in the laboratory.

What are the factors that you would consider in selecting compaction equipment? ›

“Factors include the width of the area to be compacted, the final density required, the grade of the area to be compacted, the type of asphalt mix, as well the type of materials that lay below the lift being compacted.

Explanation: The properties of soil under compaction depend upon the water content, amount of compaction, and the type of compaction. Explanation: Compaction has a great effect on soil properties, such as strength and stress-strain characteristics, permeability, compression, swelling, and water absorption.

Typical compaction requirements for a project may range from 90% to 95% of standard Proctor for non-structural areas to 98% or more of modified Proctor for heavily loaded pavements.

If no well-defined peak in the moisture density curve is observed, the soil should be compacted with significant water, e. g., corresponding to 50 to 75 percent saturation or the maximum amount of moisture that can be retained.

For large fill areas, rolling is the fastest, most efficient compaction method. Hand-held compactors can be used in smaller areas and for places that larger mobile equipment can't reach. For granular soils, vibrating plate compactors work best. Rammers or impact type machines are used for cohesive soils.

Compaction of soil is a process of densification of soil by displacing air from the pores by applying external stress on soil at different moisture content. Factors Affecting Compaction of Soil – Effect on Different Soil Types. Effect of Water Content on Compaction of Soil.

Because conditions in the field do not match the ideal conditions in a laboratory, the target compaction is scaled to a percentage of the dry density determined in the lab. This can range from 90 percent to over 100 percent.

In fact, relative soil compaction test results over 100% do not necessarily mean over-compaction because the relative compaction is based on the maximum dry density of the soil obtained by the Proctor test and this does not necessarily refer to absolute maximum dry density.

In case the compaction test results indicate values exceeding 100%, it only means that the in-situ compaction is more than that being carried out in laboratories which is treated as the basic criterion for satisfactory degree of soil compaction.

Soil texture impacts compaction as well. Coarse textured soils (sands) are considered less susceptible to compaction than fine textured soils (clays), although a dry clay soil can actually resist compaction better than a dry sand soil.

Which soil texture ranges are most vulnerable to structural damage and compaction? ›

In general, soils with fine textures (silt and clay), low organic matter contents, high porosity and weakly aggregated structure are more susceptible to serious compaction.

Type A Soils i. Type A Soils are cohesive soils with an unconfined compressive strength of 1.5 tons per square foot (tsf) (144 kPa) or greater. Examples of Type A cohesive soils are often: clay, silty clay, sandy clay, clay loam and, in some cases, silty clay loam and sandy clay loam.

Improper consolidation or compaction of concrete

Bugholes are formed when small pockets of air or water are trapped against the forms. A change in the mixture to make it less “sticky” or the use of small vibrators worked in the form has been used to help eliminate bugholes.

Rolling is the fastest and most efficient compaction method for large fill areas. In small areas where large equipment can't reach, hand-held compactors can be used. Vibrating plate compactors are best for granular soils. For cohesive soils, rammers or impact type machines are recommended.

Tamping rammers or jumping jacks, vibratory plate compactors, rollers, and more can all be found at job sites around the world to compact various soils. With these pieces of equipment, two different types of force, static force and vibratoryforce , can be utilized to achieve proper compaction.

Rainforests, dry forests, sand dunes, mountain streams, lakes, rivers, oceans, beaches, and deltas are just a few examples of where compaction, and eventually cementation, can occur.

What is Compaction? Soil compaction – Decrease in soil volume and porosity, or increase in soil bulk density, due to mechanical stress on soil, for example, from traffic of agricultural machinery. Compaction can also occur naturally.

Almost all types of building sites and construction projects utilize mechanical compaction techniques. These different types of effort are found in the two principle types of compaction force: static and vibratory.

Proctor noted that compaction is a function of four variables: (a) dry density, pd; (b) water content, w; (c) compactive effort; and (d) soil type. Compactive effort is a measure of the mechanical energy applied to a soil mass.

But dynamic compaction, as opposed to conventional shallow compaction of controlled fill, is a process of densifying soils at significant depths by applying a large impact energy at the ground surface.

What are compaction characteristics? ›

Soil compaction involves a densification and a relative variation of physical and mechanical characteristics of soils. Evaluating laboratory compaction parameters such as maximum dry density (MDD) and optimum water content (OWC) is a very important task to control field compaction for all earth-works structures.

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%.

For smaller areas, you can work in organic materials like compost, peat moss and other organic materials. Gypsum is another amendment that can be used for loosening compacted soil. Earthworms are another way to improve soil compaction.