How subgrade/pavement thickness affect the EW cut/fill area

In Earthwork, the pavement thickness can affect cut and fill results. We will go through an example on the effect of the cut/fill area with consideration of pavement thickness and the one without.

For your reference, find the;
Project file with pavement thickness here
Project file without pavement thickness here

As you can see in the image below, the pavement thickness is 0.700m which can be checked in the spread input table.

Whereas image below shows the pavement thickness of 0m which means there is no pavement on top of the platform.

Image below is the CutFill Contour that can be observed from the project file with pavement thickness and without pavement thickness. When users assign subgrade/pavement thickness, the pavement thickness will be taken into consideration when comparing the levels to generate the CutFill Contour. Hence, for projects with pavement thickness, software will compare the OGL with the subgrade/pavement thickness. Whereas for projects without pavement thickness, software will compare the OGL with the platform level. Having pavement thickness on our platform will result in a larger cut area compared to a platform without any pavement thickness.

Now, we will see the differences in the cut section view which in this project, we are viewing the same Cut Section 26. Image below shows the cut-section for platform with pavement thickness. We can see that there is a yellow line on top of the platform which indicates the pavement thickness.

Whereas for platform without pavement thickness, there are no thick yellow line indicating the pavement thickness as there are no pavement thickness on top of the platform.

To show the subgrade/pavement thickness, go to;

Options > Project Parameters > Earthwork > Detailing > Cut Section > Table > ‘Earthworks’ > Add > OK

In conclusion, pavement thickness will highly affect the cut and fill results in earthwork projects. The presence of pavement thickness on a platform can result in a larger cut area compared to a platform without any pavement thickness. This is because the software takes into account the pavement thickness when generating the CutFill Contour, resulting in different cut and fill values.