2.2.3. Mercury Intrusion Tests

The pores of the soil sample are assumed to be cylindrical. Mercury is non-infiltrating and therefore does not flow into solid pores. Under low pressure, mercury first intrudes into the gaps and large pores, then gradually intrude into the micropores with increasing mercury pressure:

$$P = -2\sigma \cdot \cos\theta / r \tag{1}$$

where *P* is the mercury intrusion pressure [Pa], *r* is the pore radius [m], *σ* is the surface tension of the intrusion liquid, *σ* = 0.484 N/m, and *θ* is the contact angle (130◦).
