Openpile

Fixed

- maximum resistance in API_clay where Pmax was wrongly calculated based on depth instead of diameter, credits to Zhenghui Qiu for spotting this.

Added

- Added soil models:
- `openpile.soilmodels.Bothkennar_clay` from the PISA joint-industry project

Added
- added properties to `Pile` object:
- `openpile.construct.Pile.tip_area` and
- `openpile.construct.Pile.tip_footprint`
- added soil springs:
- `openpile.utils.py_curves.custom_pisa_sand` and `openpile.utils.py_curves.custom_pisa_clay`
- `openpile.utils.mt_curves.custom_pisa_sand` and `openpile.utils.mt_curves.custom_pisa_clay`
- `openpile.utils.Hb_curves.custom_pisa_sand` and `openpile.utils.Hb_curves.custom_pisa_clay`
- `openpile.utils.Mb_curves.custom_pisa_sand` and `openpile.utils.Mb_curves.custom_pisa_clay`
- added soil models:
- `openpile.soilmodels.Bothkennar_clay` from the PISA joint-industry project
- `openpile.soilmodels.Custom_pisa_sand` and `openpile.soilmodels.Custom_pisa_clay`, these models can be used to customise PISA formulations based on external sources, such as an FE model.
- new functions to calculate Dunkirk Sand and Cowden Clay normalized parameters, these functions are in the module: `openpile.utils.multipliers` and are the following: `get_cowden_clay_(..)_norm_param()` and `get_dunkirk_sand_(..)_norm_param()`.

Fixed
- Stress stiffness matrix modified for not yielding negative values due to axial force component.

- added soil spring `openpile.utils.py_curves.reese_weakrock`
- added soil model `openpile.soilmodels.Reese_weakrock`

- Updates in documentation
- new methods available for `openpile.analyze.Result` class:
- new method `winkler()` replacing `simple_winkler_analysis()`, the use of the latter triggers a deprecation warning when used.
- new method `beam()` replacing `simple_beam_analysis()`, the use of the latter triggers a deprecation warning when used.
- new method `openpile.analyze.details()` that provides summary of an `AnalyzeResult` object.
- new methods available for `openpile.construct.Model` class:
- `openpile.construct.Model.get_py_springs()`
- `openpile.construct.Model.get_mt_springs()`
- `openpile.construct.Model.get_Hb_spring()`
- `openpile.construct.Model.get_Mb_spring()`
- new feature which allow user to enter a function in place of a float for springs multipliers when creating `SoilModel` objects. the function must take as input a PositiveFloat representing the depth below ground level, and as output the multiplier that shall be used by the soil spring for this depth.
- new `openpile.utils.multipliers` module that stores validated functions for use in multipliers in SoilModels objects.

- fix error in Dunkirk_sand rotational springs
- benchmarked Dunkirk sand soil model against literature from Burd et al (2020).