Creating Key In Slopes For Large Fills

This request came in from some users in the UK. They are working on a project that involves filling in some large excavation areas from an old clay pit to form a stable base for new build construction. The design requirements are to create key ins on all slopes that have a 1m bench and a 0.5m step in a sequence to create a key in for the fill.

The base of the hole is not flat, and the shape of the hole is not regular, so this is not the easiest thing to compute - we used Sideslope to create the basic shape and then CAD editing to fix up the linework created by Sideslope to build the model.

The key value of the Sideslope tool is the sideslope instruction using Slope by depth table - this allows you to define any number of benches and steps to reach the existing surface.

What makes this project trickier is that some of the existing ground slopes are steeper than 1:2 (2:1 for the US) and some are less than 1:2 (2:1 for US), meaning that for the shallower slopes in the second stage of key ins have to be computed top down and those greater than 1:2 have to be computed bottom up, this will also result in some degree of lateral step at the transition point (where the <1:2 slope meets the >1:2 slope). Again use Sideslope as a Calculator but to do the Top Downs you need to take the current toe of slope line and offset it e.g. 25m and then make a temp surface from the toe line and the offset line to which the sideslope can be computed (as per the diagram)

We also used the surface property called Shade by slope range and set that to yes and then set a min slope of 1:2 and a max slope of 1000:1 to highlight on the existing model where the slopes were greate than 1:2.

The video shows you how