# 17.11: Appendix K- The Properties of the 200 μm Sand

The sand in the old laboratory DE, with a d50 of 200 μm, is examined for the following soil mechanical parameters:

1. The minimum and the maximum density, Table K-1: Pore percentages.

2. The dry critical density, Table K-1: Pore percentages.

3. The saturated critical density, Table K-1: Pore percentages. The permeability as a function of the density, Table K-2: Permeability as a function of the porosity.

4. The angle of internal friction as a function of the density, Table K-4: The angle of internal friction as function of the pore percentage.

5. The d50 as a function of the time, Table K-3: The d50 of the sand as function of the time.

6. The cone resistance per experiment.

7. The density in the test stand in combination with the cone resistance.

The points 7 and 8 need some explanation. With the aid of a Troxler density measuring set density measurements are performed in situ, that is in the test stand. During each measurement the cone resistance is determined at the same position. In this way it is possible to formulate a calibration formula for the density as a function of the cone resistance. The result is:

$\ \mathrm{n=\frac{65.6}{C_{p}^{0.082}} \quad\text{ with: n in %, } \mathrm{C_{p}}\text{ in kPa}} \tag{k-1}$

In which the cone resistance is determined in a top layer of 18 cm, where the cone resistance was continuously increasing and almost proportional with the depth. The value to be used in this equation is the cone resistance for the 18 cm depth.

With the aid of this equation it was possible to determine the density for each cutting test from the cone resistance measurements. The result was an average pore percentage of 38.53% over 367 tests.

By interpolating in Table K-2 it can be derived that a pore percentage of 38.53% corresponds to a permeability of 0.000165 m/s. By extrapolating in this table it can also be derived that the maximum pore percentage of 43.8% corresponds to a permeability of approximately 0.00032 m/s. At the start of the cutting tests the pore percentage was averaged 38%, which corresponds to a permeability of 0.00012 m/s.

 Minimum density 43.8% Maximum density 32.7% Dry critical density 39.9% Saturated critical density 40.7%-41.7% Initial density 38.5%

 Pore percentage Permeability (m/s) 36.97% 0.000077 38.48% 0.000165 38.98% 0.000206 39.95% 0.000240 40.88% 0.000297 41.84% 41.84% 43.07% 0.000289 43.09% 0.000322
 Date d50 (mm) 22-09-1982 0.175 17-12-1984 0.180 02-01-1985 0.170 08-01-1985 0.200 14-01-1985 0.200 21-01-1985 0.200 28-01-1985 0.195 04-02-1985 0.205 26-02-1985 0.210
 Pore percentage Cell pressure kPa Angle of internal friction Dry 43.8% 50 35.1o 41.2% 50 36.0o 39.9% 50 38.3o Saturated undrained 43.8% 100 30.9o 42.1% 10 31.2o 42.1% 50 31.2o 42.1% 100 31.6o 42.2% 100 32.0o 41.8% 10 33.1o 41.3% 10 31.9o 41.2% 50 32.2o 41.1% 50 30.1o 41.1% 100 31.3o 41.1% 100 33.7o 41.0% 100 35.2o 40.5% 10 33.8o 40.3% 50 33.7o 40.4% 100 33.1o 39.8% 10 34.1o 39.2% 10 33.8o 39.2% 50 33.8o 39.2% 100 33.9o 38.2% 10 35.2o 38.1% 50 35.3o 38.1% 100 35.0o 37.3% 10 37.4o 37.0% 10 38.6o 37.0% 50 37.3o 36.9% 100 36.8o 36.2% 100 38.0o