What is [Tensiometer], Suction Plate, [Centrifugal] method of Soil Suction

By: Sr vini

Before starting soil suction test lets know what is soil suction, we also highly recommended to see the previous lesson of capillary water for better understanding, let’s start

Soil Suction –

in soil suction, word suction means stretching something. and we know due to capillary water, soil comes in tension.

And pressure due to capillary water rise is negative. also, it reduced to below atmospheric pressure, now from the previous statement we can say

the soil is in a state of reduced pressure is known as soil suction.

Soil Suction Test –

for measurement of soil suction amount, soil suction test is conducting, in this article we defined varies type of test. which used under different condition. let’s start

Suction Plate Method – 

Suction Plate

this soil suction test, A extra attachment of vacuum pump is provided (see fig) as compared to the previous method.

soil sample which suction is tested is placed over the porous plate.

below porous plate water is filled. so soil starts suction of water but pipe connected to vacuum pump applies a vacuum force by which reading is set.

mercury level pipe also connected mid between vacuum pump and soil sample,

so a reduction in pressure is measured because soil tries to suck water and vacuum try to maintain water level. when the soil starts suction vacuum force reduced. and its measure by mercury level.

Centrifugal method –


a box type instrument with brass case (as shown in fig) connect to the rotating device by a shaft,

the center part contains the porous pot. and side of porous pot maintains a gap between the inside casing of brass.

firstly a soil sample is placed on a porous pot, then throw the rotating shaft rotation is applied which give the centrifugal action of rotation,

the water from the soil comes out and drained throw the porous pot and then comes on outside of the porous pot and finely after maintaining a level inside brace casing its travel throw hole.

analysis the amount of water finally collect we can find the soil suction.

Tensiometer method –


this type of suction test, a U shape container (as shown in fig) contain a porous pot used for the test,

soil which suction is tested is filled in the container. then a pipe contains water connecting to the porous pot.

pipe contains water and at the end, it maintains a mercury level.

when the pipe valve is open soil star suction of water and mercury level drop by some hight.

finally, a stage comes where no more reduction in mercury level comes and it attains an equilibrium stage.

finally, from the change in mercury height, we can find the soil suction.

Factor affects soil suction –

this section, give only some idea about factor affecting soil suction you try to visualize what is actually happen.
1. Particle size – smaller particle size greater soil suction because fine particle soil has a large number of pores which give large capillary rise which related to soil suction

2. Temperature –  soil suction decrease as the temperature increase.

3.Water content – water content decrease soil suction increase and attain maximum value in full dry case of soil.

4. Densenceness – Dense soil give large suction and lose soil give low suction.

5. The angle of contact – when the angle of contact is zero soil suction maximum.

this all about Soil Suction Test | Soil suction Definition | Factor affecting Suction don’t  hesitate to give feedback,

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