# 17.12: Appendix L- The Properties of the 105 μm Sand

The sand in the new laboratory DE, with a d50 of 105 μm, is examined for the following soil mechanical parameters:

1. The minimum and the maximum density, Table L-1: Pore percentages, indicated are the average measured densities for the various blade angles.

2. The saturated critical density, Table L-1: Pore percentages, indicated are the average measured densities for the various blade angles.

3. The permeability as a function of the density, Table L-2: Permeabilities, indicated are the average permeabilities for the various blade angles.

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

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

6. The cone resistance per test.

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

The points 6 and 7 need some explanation. As with the 200 μm sand density measurements are performed in situ with the aid of a Troxler density measuring set. The calibration formula for the 105 μm sand is:

$\ \mathrm{n=\frac{69.9}{C_{p}^{0.068}} \quad\text{ with: n in %, }C_{p}\text{ in kPa}}\tag{L-1}$

In which the cone resistance is determined in a top layer of 12 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 12 cm depth.

With the aid of this equation it was possible to determine the density for each cutting test from the cone resistance measurements. As, however, new sand was used, the density showed changed in time. The sand was looser in the first tests than in the last tests. This resulted in different average initial densities for the different test series. The tests with a 45o blade were performed first with an average pore percentage of 44.9%. The tests with the 60o blade were performed with an average pore percentage of 44.2%. The tests with the 30o blade were performed with an average pore percentage of 43.6%. Because of the consolidation of the sand a relatively large spread was found in the first tests.

Table L-2 lists the permeabilities corresponding to the mentioned pore percentages. By extrapolation in Table L-2 a permeability of 0.00017 m/s is derived for the maximum pore percentage of 51.6%.

The sand bed is flushed after the linear tests because of the visibility in the water above the sand. In the tables it is indicated which soil mechanical parameters are determined after the flushing of the sand bed.

 Minimum density 51.6% Maximum density 38.3% Initial density 30 o 43.6% Initial density 45 o 44.9% Initial density 60 o 44.2% After the flushing Minimum density 50.6% Maximum density 37.7% Saturated critical density 44.5%
 Pore percentage Permeability (m/s) 42.2% 0.000051 45.6% 0.000082 47.4% 0.000096 49.4% 0.000129 Initial 43.6% 0.000062 44.2% 0.000067 44.9% 0.000075 After the flushing 39.6% 0.000019 40.7% 0.000021 41.8% 0.000039 43.8% 0.000063 45.7% 0.000093 48.3% 0.000128
 Date d50 (mm) 06-08-1986 0.102 06-08-1986 0.097 06-08-1986 0.104 06-08-1986 0.129 06-08-1986 0.125 06-08-1986 0.123 29-08-1986 0.105 29-08-1986 0.106 29-08-1986 0.102 16-09-1986 0.111 16-09-1986 0.105 16-09-1986 0.107
 Pore percentage Cell pressure kPa Angle of internal friction Saturated undrained After the flushing 44.7% 100 33.5o 44.9% 200 33.3o 44.5% 400 32.8o 42.6% 100 35.0o 42.1% 200 35.5o 42.2% 400 34.8o 39.8% 100 38.6o 39.9% 200 38.3o 39.6% 400 37.9o