Soil Properties 866B10
1. **Problem statement:**
Given a soil sample with:
- Initial mass (wet mass) $M = 301.4$ g
- Dry mass $M_d = 258.0$ g
- Total volume $V = 161.4$ cm$^3$
- Relative density (specific gravity) $G = 2.66$
Find:
- Mass of water
- Volume of water
- Volume of solids
- Density
- Dry density
- Water content
- Void ratio
- Porosity
2. **Formulas and important rules:**
- Mass of water $M_w = M - M_d$
- Volume of solids $V_s = \frac{M_d}{G \times \rho_w}$ where $\rho_w = 1$ g/cm$^3$ (density of water)
- Volume of water $V_w = V - V_s$
- Density $\rho = \frac{M}{V}$
- Dry density $\rho_d = \frac{M_d}{V}$
- Water content $w = \frac{M_w}{M_d} \times 100\%$
- Void ratio $e = \frac{V_w}{V_s}$
- Porosity $n = \frac{V_w}{V} \times 100\%$
3. **Calculations:**
- Mass of water:
$$M_w = 301.4 - 258.0 = 43.4\text{ g}$$
- Volume of solids:
$$V_s = \frac{258.0}{2.66 \times 1} = \frac{258.0}{2.66} = 97.0\text{ cm}^3$$
- Volume of water:
$$V_w = 161.4 - 97.0 = 64.4\text{ cm}^3$$
- Density:
$$\rho = \frac{301.4}{161.4} = 1.9\text{ g/cm}^3$$
- Dry density:
$$\rho_d = \frac{258.0}{161.4} = 1.6\text{ g/cm}^3$$
- Water content:
$$w = \frac{43.4}{258.0} \times 100 = 16.8\%$$
- Void ratio:
$$e = \frac{64.4}{97.0} = 0.7$$
- Porosity:
$$n = \frac{64.4}{161.4} \times 100 = 39.9\%$$
4. **Summary:**
- Mass of water = 43.4 g
- Volume of water = 64.4 cm$^3$
- Volume of solids = 97.0 cm$^3$
- Density = 1.9 g/cm$^3$
- Dry density = 1.6 g/cm$^3$
- Water content = 16.8 %
- Void ratio = 0.7
- Porosity = 39.9 %