Question

give reason for application of oil or grease on inside wall surface of core cutter​

Answer 1

main reason for application of oil or grease on inside wall surface of core cutter is to reduce friction between the surfaces of the cutter. this friction further creates sound pollution and generate heat . to prevent this application of oil or grease is done.

hope it helps ...

Answer 2

Cylindrical core cutters of 130mm long and 100mm diameter are used for testing the in-situ compaction of cohesive and clay soils placed as fill. By using core cutter method, bulk density of soil can be quickly calculated and by determining the moisture content of the soil the dry density of the fill can be calculated and hence the voids percentage. A high percentage of voids indicates poor compaction of soil.
A cylindrical core cutter is a seamless steel tube. For determination of the dry density of the soil, the cutter is pressed into the soil mass so that it is filled with the soil without disturbing the core contents. The cutter filled with the soil is lifted up. The mass of the soil in the cutter is determined.

Where,

M= mass of the wet soil in the cutter

V= internal volume of the cutter

w= water content.