VectorExpertHome · Projects · Drains and sewers
Drains and sewer trenches, with the excavation at every chainage.
Draw the trench or the open drain once, set the fall along the route, and CivilSurvey Expert gives the excavation at every chainage against the surveyed ground, with bedding or lining as layers of their own. Then print the sections, the long section and the volume abstract. CAD is built in, so no AutoCAD is needed.
Typical section
The typical trench section
Draw the trench in the Template Designer, or import a .dwg. Vertical sides are a slope of 0; battered sides are 1 V : x H. Open drains are drawn the same way, as a trapezoidal or rectangular section.
Schematic, not to scale.
- Natural surface (NSL)
- The ground, from the level book at every chainage.
- Trench
- The excavation from the ground down to the trench bottom, quantified as cut.
- Bedding
- The bedding under the pipe, or the lining of an open drain, as a layer with its own quantity.
- Side slopes
- Slope sets with 0 for vertical sides or 1 V : x H for battered ones, changed at any chainage.
The job, start to finish
A drain or sewer job in six stages
The same six stages as every CivilSurvey Expert project. Each links to the full details and a live demo.
- 01
Book the levels
Type or import the level book for every chainage along the line. R.L.s are worked out by the height-of-instrument method and checked arithmetically.
- 02
Generate the sections
Place the trench template on every chainage from the design sheet: give the level and the fall as a gradient in percent (1 in 300 is about 0.33 %), and the level at each chainage follows. The sides run up to the ground and their tops are found for you.
- 03
Adjust by hand
Deepen a reach, change to battered sides where the ground is poor, or move points in the built-in CAD. Areas update as you work.
- 04
Adjust to a target
When a section has to carry a given cut or fill area, Dynamic Area Adjustment moves the layer in small steps until the area is reached.
- 05
Reverse field book
Back-calculate a level book, B.S., I.S. and F.S., that matches the final levels, with change points added at staff limits.
- 06
Deliver
Print every section with its datum band and area table, the long section along the line, and the volume abstract of the excavation and each layer.
What you hand over
From one project file
| Output | What it holds |
|---|---|
| Cross-section sheets | Every chainage on A0 to A5 or Letter, with the datum band and the area table for each layer. |
| Long section | The ground and the trench bottom along the whole line. |
| Volume abstract | Excavation and the bedding or lining quantity by average end area, written to Excel. |
| Level book | A field book that matches the final levels, ready to check against. |
| DWG drawings | Any section exported to DWG when a consultant asks for it. |
Common questions about drains and sewers
Can the trench sides be vertical?
Yes. In a slope set, 0 means vertical. Use 1 V : x H for battered sides, and apply a different slope set at any chainage.
How do I set the fall of the drain or sewer?
On the design sheet, as a gradient in percent: 1 in 300 is about 0.33 %. Give the level, choose the template, and Apply places it at every chainage.
Can I get the bedding quantity separately?
Yes. Make the bedding its own layer; each layer has its own area against the layer it is measured from, so the abstract lists it separately from the excavation.
Does it work for open drains too?
Yes. Draw the drain as a trapezoidal or rectangular template, with or without lining as a separate layer, and place it along the route the same way.
How is the excavation quantity calculated?
Each section's area is worked out by trapezoidal strips; the volume between sections is by average end area, written to Excel.
Do I need AutoCAD to draw or print the sections?
No. Sections are drawn and printed in CivilSurvey Expert's built-in CAD. Export DWG only when someone else needs the drawings.