Divided Bar Method:
The Divided Bar method for testing thermal conductivity properties is the most practical method for testing rock core samples in the laboratory. This steady state test is based
on comparing the temperature drop across a rock sample compared with the temperature difference measured across a standard material.
Needle Probe Method:
This method provides a procedure for determining the thermal conductivity of soil and soft rock using a transient heat method. This test method is applicable for both undisturbed and remolded soil specimens and soft rock specimens. This test method is suitable only for isotropic materials. The testing is carried out in accordance with ASTM D5334.