The most suitable test for measuring the permeability of clayey soils in the laboratory is ___________.

For the flow setup shown, hydraulic conductivities are $k_1=10$ mm/s (Soil 1) and $k_2=1$ mm/s (Soil 2). Unit weight of water $=10$ kN/m$^3$. Ignore velocity head. At steady state, what is the total head (in m, rounded to two decimals) at the junction of the two samples?

| Point | Staff Readings Back side | Staff Readings Fore side | Remarks |
|---|---|---|---|
| P | -2.050 | - | 200.000 |
| Q | 1.050 | 0.95 | Change Point |
| R | - | -1.655 | - |