Using Geological Data for Rock Quantities: Part I

There are tons of ways to incorporate geotechnical and geological in your Civil 3D work. I have done a few different projects using a variety of techniques depending on what type of data it was, what the engineer was trying to learn, and what type of data that the geological professional could deliver.

As with anything I write about, my goal is not to give you a specific step by step that works in every situation. I want you to get creative and think of ways to work with what you have and what you can get.

So the project was a sewer retrofit. An entire township was served with private septic systems and needed sewers. The trouble was that there were several layers of rock under the existing roads. Our job was to create a pipe layout that minimized the amount of rock to be removed. There were different costs associated with the removal of the different layers of rock.

The geologist did seismic refraction (or if you really want to geek out you can read this article about seismic refraction). I talked to him on the phone and tried every which way to figure out how to bring the data over- asked about ascii, asked about landxml... but it turned out our only option was dxf that showed the horizontal path of the seismic equipment, and their corresponding profiles.

Here is an example of one of the profiles:

This is a 1:1 profile, in dxf form. Those black blotches are text- but not even real text. Just fragments and primitives.In my head I was thinking... well, it was something like "How am I supposed to do anything with this lovely stuff?".

So the idea I came up with was to make alignments from the horizontal paths, then sample a profile view against an EG that I had for the area. Then, I traced the critical profiles using a layout profile, and erased the dxf geometry, so I wound up with something like this:

Next, I made an assembly. Now, I talked to the geologist about how wide I could assume this layer of rock was. They told me what was reasonable and that is how I built the assembly.

Next, I created corridors from the equipment paths plus the critical rock profiles:

 

From these corridors, I could build rock surfaces for sampling on to my pipe profiles and creating quantity reports based on pipe trenching.

I'll show you how I did the pipe trenching tomorrow, and then the quantity reports later this week.