\[ Q = kiAt \quad \Rightarrow \quad k = \frac{Q}{iAt} \] \[ k = C_v \cdot m_v \cdot \gamma_w \]
Hazen 식: \[ k = c_1 \cdot D_{10}^2 \quad (\text{cm/s}), \quad c_1 = 100 \sim 150 \text{ (사질토)} \] Taylor 식: \[ k = c \cdot D_{10}^2 \cdot \frac{\gamma_w}{\eta} \cdot \frac{e^3}{1+e} \] Kozeny-Carman 식: \[ k = \frac{D_{10}^2}{K' S} \cdot \frac{\gamma_w}{\eta} \cdot \frac{e^3}{1+e} \] Casagrande 식 (가는 모래): \[ k = 1.4 \cdot e^2 \cdot K^{0.85} \]
\[ Q = A \cdot v = A \cdot k \cdot i, \quad i = \frac{\Delta h}{L} \]
수평흐름: \[ Hk_h = H_1 k_1 + H_2 k_2 + H_3 k_3 \] 연직흐름: \[ \frac{H}{k_v} = \frac{H_1}{k_1} + \frac{H_2}{k_2} + \frac{H_3}{k_3} \]
동수경사:
\[
i = \frac{\Delta h}{L}, \quad i_{cr} = \frac{\gamma_{sub}}{\gamma_w}
\]
보일링 안전율:
\[
F_s = \frac{i_{cr}}{i} = \frac{\gamma_{sub}}{\gamma_w} \cdot \frac{L}{\Delta h}
\]
파이핑: 동일 계산 가능
히빙:
\[
F_s = \frac{\text{저항력}}{\text{작용력}} = \frac{\text{극한지지력}}{\text{재하중강도}}
\]
\[ Q = k \cdot \frac{n_f}{n_d} \cdot h \] ( \(n_f\): 유로수, \(n_d\): 등수두면수 )