Foundation, Concrete and Earthquake Engineering

What are Sample Disturbance Parameters in Soil Investigation?

In our previous post we have discussed about disturbance of soil sample in different stages of collection. Now we have to measure how much disturbance occurred in soil sampling.

At first we will learn about the basic requirements of sample:

While sampling by forcing samplers into ground they should result-

-minimum displacement

-minimum remolding

-minimum disturbance as possible

Typical cutting edge for soil samplingThe degree of disturbance produced by sampler depends mainly on following three features that should be carefully controlled and proportioned during designing:

1. Cutting edge

2. Friction in inside wall

3. Non-return valve

We are providing a image of typical cutting edge below. The parameters that we will discuss now are related to this image:

The parameters that determines sample disturbance are:

a. Inside clearance ratio

b. Outside clearance ratio

c. Area ratio

a. Inside clearance ratio:

Generally defined as ci and the expression for inside clearance ratio is

Soil sample disturbance: Inside clearance ratio
 This term is self explanatory. (see image above)

b. Outside clearance ratio

Generally defined as co and the expression for outside clearance ratio is

Soil sample disturbance: Outside clearance ratio

This term is also self explanatory. (see image above)

c. Area ratio

Generally defined as Ar and the expression for area ratio is

Soil sample disturbance: Area ratio
 Dear reader necessary limit of these parameters and some other parameters will be discussed in our nest post, in our upcoming post we will discuss about simple method for determination of ground water table.

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