Package: pyslope
pySlopepySlope is a 2D slope stability module based on bishops method of slices. This module allows for the following parameters:unlimited horizontal geological unitswater tableuniform loadsline loadsslope search limitsThis module can return plots for the critical failure slope or plots for all failure slopes below a certain factor of safety.Project PurposeThe purpose of this project is two fold:Create a free online slope stability softwareProvide a pythonic solution to implementing Bishop's method based on object oriented coding principlesPerforming a slope stability calculation by hand is extremely uneconimical and time consuming. The problem involves a lot of geometrical mathematics which can make the calculation hard to achieve with only excel. Python packages exist for geometrical mathematics which makes Python well suited for implementing a slope stability analysis package. There is however, no well-documented open-source slope stability software that can currently be found online. This package aims to fill that gap.Functionality and usageA typical use case of thepySlopepackage involves the following steps:Create aSlopeobjectCreateMaterialobjects and assign toSlopeCreateUdlorLineLoadobjects and assign toSlopeSet water tableSet analysis limitsAnalyse slope for critical factor of safetyCreate plotsYou can follow along with this example below in this web-based binder jupyter notebook.Creating a SlopeThe creation of aSlopeinstance involves the input of the:slope height (m) andangle (deg) orlength (m)Only one of the values is used out of the length and angle, the other value should be set to None.s=Slope(height=3,angle=30,length=None)Defining MaterialsThe creation of aMaterialobject involves the input of:unit weight (kN/m3)friction anglecohesion (kPa)depth from top of slope to bottom of material layer (m)Once a material is defined it can then be assigned to theSlopeinstance.m1=Material(unit_weight=20,friction_angle=45,cohesion=2,depth_to_bottom=2)m2=Material(20,30,2,5)# Material defined with positional argumentss.set_materials(m1,m2)# An unlimited number of materials can be assigned at one timeThe slope will know to order the materials based on the depth to the bottom of the strata so the order that the materials are provided isn't important. It is important that the same depth isnt provided twice for two different materials, and attempting this will raise an error.Defining Uniform LoadsThe creation of aUdl(uniform distributed load) object involves the input of:magnitude of load (kPa)offset of load from crest of slope (m) (default 0 m)length of load (m) (default infinite)u1=Udl(magnitude=100,offset=2,length=1)# by default offset = 0 (m) and length = None.u2=Udl(magnitude=20)# assign uniform loads to models.set_udls(u1,u2)Defining Line LoadsThe creation of aLineLoadobject involves the input of:magnitude of load (kN / m)offset of load from crest of slope (m) (default 0 m)# define line load, similiar to Udl except there is no length parameter and magnitude is in units (kN/m)p1=LineLoad(magnitude=10,offset=3)# assign line loads to slopes.set_lls(p1)Defining Water TableBy default there is no water table. The water table is defined by its depth from the top of the slope (m).s.set_water_table(4)Defining Analysis LimitsAnalysis limits can be specified as a general left and right limit, OR as a set of limits which control the range from which the top of failures can occur and the bottom of failures can occur.Currently the model coordinates are dynamic in that the overall model dimensions are based on the size of the slope.Theget_top_coordinatesandget_bottom_coordinatesmethods can be useful to help define limits in reference to the top and bottom of the slope.s.set_analysis_limits(s.get_top_coordinates()[0]-5,s.get_bottom_coordinates()[0]+5)Analysing SlopeTo analyse theSlopethe analyse_slope() method is called. By default 2000 iterations are run with 50 slices per failure plane.# The user can change the number of slices and iterations with the method below.# The line below is implicitly called and only required by the user if they want to change iterationss.update_analysis_options(slices=50,iterations=2500)# run analysiss.analyse_slope()Interpretting resultsAfter analysing the slope the critical factor of safety can be taken as below.print(s.get_min_FOS())A more useful output might be a plot. Currently there are 3 main plots that can be called.s.plot_boundary()# plots only the boundarys.plot_critical()# plots the boundary with the critical failure of the slopes.plot_all_planes(max_fos=i)# plots boundary with all slope failures below fos i (where i is number)Examples of the plots are shown below.Dynamic AnalysisInstead of standard static analysis the user also has the option to make load objectsdynamic. The user can then perform a dynamic analysis rather than static, which moves the load in order to determine the required offset for a minimum factor of safety.Considering the example above, we can continue and make u1 dynamic.# remove udl object load from slopes.remove_udls(u1)# now lets add the udl again but this time set the load as 'dynamic'# for all loads and materials we also have the option to set the color ourselves# lets try set the color as 'purple's.set_udls(Udl(magnitude=100,length=1,offset=2,dynamic_offset=True,color='purple'))# run dynamic analysis aiming for a FOS of 1.4s.analyse_dynamic(critical_fos=1.4)# get dictionary of all determined minimum FOS with key value pairing of offset : values.get_dynamic_results()# or can print the values outs.print_dynamic_results()From this we get the following output results:Offset: 0.000 m, FOS: 1.288Offset: 0.735 m, FOS: 1.402Offset: 1.463 m, FOS: 1.510Offset: 5.186 m, FOS: 1.684We can also get a plot as after running dynamic analysis all plots are based on the final iteration of the dynamic analysis.Installing the packageIf you want to install thepyslopepackage, you run this one-liner:pipinstallpyslopeNOTE: You need Python 3 to install this package (you may need to writepip3instead ofpip).The library dependencies are listed in the filerequirements.txt, but you only need to look at them if you clone the repository.
If you install the package viapip, the listed dependencies should be installed automatically.TestingThis project usespytestto run tests and also to test docstring examples.Install the test dependencies.pipinstall-rrequirements.txtRun the tests from the top level directory.$pytest===3passedin0.13seconds===ValidationThe results of this project have been validated against Slidev6.0 and Hyrcanv1.75. See thedocumentationfor more detailFuture WorkThere is a lot of room for expansion of the project, and the direction of the project will strongly be affected by open-source contribution from the community. Some things in the short to medium term scope of work are:better documentationunit testinghorizontal loadsContributingThe guidelines for contributing are specifiedhere.SupportThe guidelines for support are specifiedhere.DevelopingThis project usesblackto format code andflake8for linting. We also supportpre-committo ensure
these have been run. To configure your local environment please install these development dependencies and set up
the commit hooks.$pipinstallblackflake8pre-commit
$pre-commitinstallReleasingReleases are published automatically when a tag is pushed to GitHub.# Set next version numberexportRELEASE=vX.X.X# Create tagsgitcommit--allow-empty-m"Release$RELEASE"gittag-a$RELEASE-m"Version$RELEASE"# Push (for working from a fork)gitpushupstream--tags# if not working from fork would instead be# git push origin --tagsOr set a tag with Github Desktop.License