Earthwork Quantities

Introduction

Proposed cross sections generated from corridor modeling DTMs required modifcations to the conventional earthwork input files. Both new levels and new earthwork computation methods will have to be accounted for. The new method to compute earthwork requires the top surface, the subgrade line, and tracing the existing ground line for wedging surfaces to be defined as the finished grade. The Proposed Finish Grade, Undercut (if applicable), and the Existing Ground sections are key components of the input file.

Breaking the side slope into two levels when it intersects the subgrade line for graded shoulders is no longer required with this new method. Earthwork is broken down into three categories, depending on the required input file. These earthwork input files can be found in the Roadway Workspace.

Simple Earthwork (CMT_XSQuan_Eawk.inp)

Earthwork with Shallow Undercut (CMT_XSQuan_Eawk_ShallowUnd.inp)

Earthwork with Regular Undercut(CMT_XSQuan_Eawk_Und.in

Note that shallow undercut and regular undercut earthwork input files may not be combined into one input. Shallow undercut excavation (subgrade exc) and backfill quantities are paid for separately from regular undercut provisions. In addition, shallow undercut quantities do not appear in the station to station portion of the earthwork balance sheet. They are reported as contingency line items after the grand total.

Simple Earthwork

Eathwork involving only embankment and excavation. The subgrade line and the side slope lines are used to determine cross section cut and fill areas.

Earthwork with Shallow Undercut

Include what is defined for simple earthwork with the additional consideration to shallow undercut. Shallow undercut lines always tie to the subgrade line. Since shallow undercut is backfilled with a different soil type used for roadway construction, a line statement "Proposed Undercut" and the Soil Type (usually Select_Material or Class_IV) must be defined in the earthwork input file. The earthwork log file will report the normal cut and fill areas under the soil type "Suitable" while shallow undercut excavation is reported as "Subgrade Exc". Backfill material is report as "Fill" under the appropriate soil type. The shallow undercut excavation and backfill areas may be the same or can be different depending on if the earthwork linework is completely below existing ground or it is partially above or all above existing ground.

Earthwork with Regular Undercut

Include what is defined for simple earthwork with the additional consideration to regular undercut. Regular undercut lines always tie to the subgrade line. Since regular undercut is backfilled with the same soil type used for roadway construction, a line statement "Proposed Undercut", Soil Type must be defined as the same material as the Proposed Finished Grade and Existing Ground Line (usually Suitable) in the earthwork input file. The earthwork log file will report the normal cut as "Common Exc", undercut as "Subgrade Exc", and "Fill" includes the undercut backfill material (same).

Excercise Data:

Download dataset ZIP file HERE.

Excercise 1: Compute Simple Earthwork

Step 1.
While in the file R2635C_RDY_XSC_Y15.DGN, locate and process the earthwork input file CMT_XSQuan_Eawk.inp. Name the log file XS_Rep_ewY15.log.

Step 2.
Take random measurements of the earthwork shape areas in the XSC file and compare them to the log file. Note the subgrade line and not the top surface lines is used for earthwork.

XS Earthwork Subgrade Elements (at Station 18+50)

XS Earthwork Report

Step 3.
"Undo All" to delete all of the earthwork shapes and get ready for the next excercise.

Excercise 2: Compute Earthwork with Shallow Undercut

Step 1.
While in the file R2635C_RDY_XSC_Y15.DGN, locate and process the earthwork input file CMT_XSQuan_Eawk_ShallowUnd.inp. Name the log file XS_Rep_ewY15SUC.log.

Step 2.
Take random measurements of the earthwork shape areas in the XSC file and compare them to the log file. Note the shallow undercut excavation quantity is reported as Select_Material, Subgrade Exc and the amount of select material to be backfilled is reported as Select_Material, Fill.

XS Earthwork Shallow Undercut Shapes (in red)

XS Earthwork Report

Step 3.
"Undo All" to delete all of the earthwork shapes and get ready for the next excercise

Excercise 3: Compute Earthwork with Regular Undercut

Step 1.
While in the file R2635C_RDY_XSC_Y15.DGN, locate and process the earthwork input file CMT_XSQuan_Eawk_Und.inp. Name the log file XS_Rep_ewY15RUC.log.

Step 2.
Take random measurements of the earthwork shape areas in the XSC file and compare them to the log file. Note the regular undercut excavation quantity is reported as Subgrade Exc and the Fill area includes undercut backfill quantities of the same soil type.

XS Earthwork Regular Undercut Excavation Shapes (in shaded blue)

XS Earthwork Report

Step 3.
"Undo All" to delete all of the earthwork shapes and get ready for the next excercise

Roadway Design Corridor Modeling-Training Exercises-V8i SS1 Refresh

Roadway Design
Corridor Modeling-Training Exercises-V8i SS1 Refresh