On the Home Tab of Civil 3D in the Profile & Sections Views Panel, select the Create Sample Lines command. Select the desired alignment and in the Create Sample Line Group dialog, select the desired data you want to include.
Set the Surface Style to Existing.
Once you have selected the pipes, select OK to proceed to the Sample Line Tools Toolbar.
In the Sample Line Tools Toolbar, select the Sample Line Creation Methods and choose By Range of Stations. Key in the desired station values for the start and end station of the sample lines.
Determine how wide you would like the cross sections to be by inputting the distance left and right. Also the Sampling Increments will determine how often the cross sections are sampled. Additional samplings can also be set. Click OK and close out of the Sample Line Tools Toolbar. This will create all of the Sample Lines.