Calculation and determination of the soil compaction coefficient

Calculation and determination of the soil compaction coefficient Soil compaction coefficient - what is it and how to calculate it

An indicator such as soil compaction coefficient , demonstrates how much the volume of bulk material will change after compaction or even transportation. It is determined by the ratio of maximum and total density. Each type of bulk material consists of elements, or rather grains. There will always be voids between them, that is, pores. The higher the process of voids, the more volume the substance will occupy.

To put it simply, we suggest that you remember a child's snowball game. To make a good snow ball, you should scoop a large handful from the snowdrift and squeeze as much as possible. Thus, you will reduce the number of voids between the snowflakes, that is, compact them.

This will decrease the volume. The same will happen if you pour cereal into a glass, and then shake or tamp it with your fingers.

You will receive a compaction of the grains. In other words, the compaction ratio will be the difference between materials in its standard condition and compaction.

Why do you need to know the KU?

To know the data on the compaction performance for bulk materials, you should:

  • Check if you received as much material as you ordered.
  • Buy the right amount of dropout, sand, crushed stone in order to fill the foundation pit, ditches or pits.
  • Calculate the likely ground shrinkage when laying foundations, roads or paving slabs.

  • Correctly calculate the amount of concrete mix for pouring the foundation and floors.

Next, we will consider each of the methods separately.


Coefficient during transportation

Calculation and determination of the soil compaction coefficient For example, a dump truck carries you 8 m 3 rubble from the quarry to the site. On the way, he will come across potholes and pits, and due to the impact of vibration, crushed stone grains will begin to thicken, which is why the volume is reduced to 7. 27 m 3 .

This will shake down the material. How do you know that the required amount of goods was brought to the object, as indicated in the documentation? To do this, you need to know the final volume of the material, as well as the degree of compaction (for crushed stone it is 1.1). Both numbers should be multiplied together to get the initial volume. If the data does not match what is written in the documents, then you are not dealing with rubble, but with a dishonest seller.

Consolidation when filling holes

In the construction industry, there is such a thing as shrinkage. The earth or other bulk material will be compacted and reduced in volume under the influence of its own weight or under the pressure of various structures (paving slabs and foundations). The shrinkage process must be taken into account when filling pits and ditches, because if you do not do this, then after a while a pit will form. To place an order for the required amount of material, you must first find out the volume of the pit.If you know its shape, width and depth, then you can use an online calculator to calculate.

Further, the resulting figure should be multiplied by the indicator of the bulk density of the material and the degree of compaction. When the selected material is poured into the hole, a mound should eventually turn out. All this is due to the fact that, in natural conditions, shrinkage occurs after a certain time interval, and the process can be accelerated by tamping. It is carried out manually or even using special devices.

Compaction during construction

In construction, determining the coefficient of soil compaction is especially important.

You have probably heard of cases when cracks began to appear in buildings after construction. What about pits on new roads or collapsing paving slabs in the yard and on paths?

This happens if the soil shrinkage is incorrectly calculated, and appropriate measures are not taken to eliminate it. In order to know the degree of shrinkage, the compaction coefficient is required. It will help you understand how much this or that soil will be compacted in your conditions. For example, under the pressure of the weight of tiles, buildings or even asphalt.

Some types of soil have such a high shrinkage coefficient that they even have to be replaced. The rest of the types are specially tamped before the start of construction.

How to find out the degree of compaction

It will be easiest to take all the data about the compaction coefficient from GOSTs. They will be calculated for different types of material.

Under laboratory conditions, the compaction coefficient is measured as follows:

  1. The bulk or total density of the material is measured, and for this you need to measure the mass and volume of the sample, calculate them ratio.

  2. After that, the sample should be shaken or compressed, the mass and volume should be measured, and then the maximum density level should be determined.
  3. By the ratio of the two indicators, you can calculate the coefficient.

Documents will indicate the average values ​​of the indicator. The coefficient may vary depending on various factors. The figures given in the table are arbitrary, but still help to calculate the shrinkage of a large volume of material.

The following factors will influence the compaction index value:

  • Calculation and determination of the soil compaction coefficient Features of transport and method of transportation. If the material is transported by rail or potholes, it will be compacted much more than when transported on a flat road / sea.
  • Granulometric composition (grain shape, size, ratio). If the composition of the material is non-uniform and there are flaky particles (needle-shaped or flat), then the coefficient will be lower. In the presence of a large number of small particles, the indicator will be higher.

  • Humidity. The higher it is, the less the desired indicator will turn out.
  • Tamping method. If the material is compacted by hand, the degree of compaction will be less than after using vibrating mechanisms.
  • Bulk density.

    The compaction factor will be directly related to the bulk density. As mentioned earlier, in the process of compaction or transportation, the density of the material changes, because there are fewer voids between the particles. For this reason, the bulk density always differs when loaded into the vehicle and after arriving at the customer. This difference can be calculated and checked thanks to the compaction ratio.

It will not be superfluous to find out specific indicators for materials such as asphalt, crushed stone, clay, coal, expanded clay, rocky soil, expanded clay, sand, screening and ASG.

The compaction ratio is a very important indicator that makes it possible to know how much bulk material to order. It will give you the opportunity to check whether it is true that they brought you as much as you ordered. The indicator is also required for builders to know when building houses in order to correctly calculate the load on the base.