Pile testing functionality

groundhog.deepfoundations.axialcapacity.piletesting.piletest_chinkondler(loads, settlements, no_discard_points=1, max_settlement=50, selected_settlement=40, show_fig=True, **kwargs)[source]

Extrapotates a pile head load-settlement curve based on the procedure by Chin-Kondler. The settlements are divided by the corresponding loads. This yields a straight line in a graph of this fraction vs settlement. The user selects how many points to discard and the fitting happens using np.polyfit. An extrapolated load-settlement curve is calculated and plotted for the user to check the results.

Parameters:

  • loads – List of loads recorded during the load test. Note that unload-reload loops should be removed before running the algorithm (\(Q\)) [kN]

  • settlements – List of settlements recorded during the load test. Should be the same length as the list with loads (\(s\)) [mm]

  • no_discard_points – Number of points at the start of the curve to discard for the fitting of the straight line.

  • max_settlement – Maximum settlement used for plotting the reconstructed pile head load-settlement curve (\(s_{max}\)) [mm]. Optional, default=50mm.

  • selected_settlement – Settlement as which pile capacity is calculated (e.g. 10% of OD) (\(Q_{s=s_{\text{selected}}}\)) [kN]. Optional, default=40mm.

  • show_fig – Boolean determining whether the figures for the Chin-Kondler construction need to be plotted (default behaviour) or returned in the output dictionary.

\[ \begin{align}\begin{aligned}\frac{s}{Q} = a + b \cdot s\\Q_{\text{ult}} = 1 / b\end{aligned}\end{align} \]
Returns:

Dictionary with the following keys:

  • ’intercept [mm/kN]’: Coefficient \(a\) from the linear regression [mm/kN]

  • ’slope [1/kN]’: Slope \(b\) for the linear regression [1/kN]

  • ’Correleation coefficient [-]’: Pearson correlation coefficient for the points used for the construction.

  • ’Qmax [kN]’: Ultimate pile resistance (fully mobilised shaft and base) (\(Q_{\text{ult}}\)) [kN]

  • ’Qdisp [kN]’: Pile resistance at the selected displacement level (e.g. 10% of OD) (\(Q_{s=s_\text{selected}}\)) [kN]

  • ’Settlements [mm]’: List with settlements for the load-displacement reconstruction [mm]

  • ’Q [kN]’: List with loads for the load-displacement reconstruction [kN]

  • ’construction_fig’: Figure with the linear regression construction (for inspection of the goodness-of-fit)