When deeper layers have increasingly greater density, the seismic refraction method is fast.

In Dutch cone test, the angle of vector of cone is ____

The number and disposition of bore holes are varied, depending upon ___

The penetration resistance is driving the sampler ______

The general exploration gives information about which of the following features?

Rotary boring can also be called as _______

Which of the following method is adopted for fast boring?

Thick wall samplers have area ratio______