We were discussing about sample disturbance in soil sampling process. In previous post we have discussed about disturbance before sampling. Now we will discuss about disturbance during and after sampling.
Disturbance During Sampling
During sampling the soil sample entered into the sampler by forcing them to take their position in sampler. We know there have some friction between sampler and soil and other mechanism that disturb the sample.
We can summarize this mechanism as below:
a. Disturbance by displacing soil by wall of sampler
b. Friction between sampler and sample
c. Adhesion between sampler and sample
Another factor that influences the disturbance is inside clearance between cutting shoe and sample.
Disturbance After Sampling
When a soil sample is collected carefully, least disturbing it which is practical during sampling and before sampling, may be disturbed by next steps of sampling process like
During transporting, in many cases, sample becomes disturbed. Sometimes in case of improper sealing of tube, moisture lose may be taken place.
In designing a soil sampler, the main criteria are that they don’t produce much disturbance. In determining disturbance of soil during sampling some parameters like ci, co, Ar, RQD and recovery ratio etc are used and specific limit of these parameters for different soil type are provided. Dear reader we will discuss all these parameters in our upcoming posts.