One-dimensional consolidation

pyeng.geotechnical.consolidation.onedimensional.consolidation_drainage_janbu(time, consolidation_coefficient, drainage_path_length, drainage_type='double', stress_distribution='constant', fail_silently=True, **kwargs)

Calculates the average degree of consolidation for different drainage characteristics and initial stress distribution. For double drainage, an analytical solution is obtained by curve fitting to the numerical solution. For triangular stress distribution and double drainage, the same solution as for a constant stress distribution and double drainage is obtained. For one-sided drainage, this is no longer the case. For one-sided drainage and triangular stress distributions, the chart according to Janbu (1956) is interpolated.

In a thin layer of partially drained soil, a uniform stress distribution applies. In deep homogeneous clay, a triangular stress distribution, decreasing with depth applies.

Note that the drainage path length is half of the layer thickness for double drainage and equal to the layer thickness for single-sided drainage.

Parameters:
  • time – Drainage time (\(t\)) [\(s\)] - Suggested range: 0.0<=time
  • consolidation_coefficient – Coefficient of consolidation (\(c_v\)) [\(m2/yr\)] - Suggested range: 0.1<=consolidation_coefficient<=10000.0
  • drainage_path_length – The length of the drainage path (\(H_{dr}\)) [\(m\)] - Suggested range: 0.0<=drainage_path_length
  • drainage_type – Double-sided or single-sided drainage (\(-\)) [\(-\)] (optional, default=”double”)Options: (“constant”,”triangular increasing”,”triangular decreasing”), regex: None
  • stress_distribution – Type of initial stress distribution (\(-\)) [\(-\)] (optional, default=”constant”)Options: (“constant”,”triangular increasing”,”triangular decreasing”), regex: None
\[ \begin{align}\begin{aligned}T_v = \frac{c_v t}{H_{dr}^2}\\\text{Double drainage: }\\T_v = \frac{\pi}{4} (\frac{U}{100})^2 \quad U < 60\%\\T_v = 1.781 - 0.933 \log(100 - U) \quad U \geq 60\%\end{aligned}\end{align} \]
Returns:Average degree of consolidation (\(U\)) [\(%\)], Time factor (\(T_v\)) [\(-\)]
Return type:Python dictionary with keys [‘consolidation_degree [%]’,’time_factor [-]’]
../../../_images/consolidation_drainage_janbu.PNG

Solutions for one-dimensional consolidation equation for different consolidation characteristics and stress distributions

Reference - Janbu (1956).