This subassembly creates a flat-bottom trench with equal sideslopes, and up to three layers of backfill material. The width of the trench is determined by a user- specified width and minimum pipe cover.
Note: All dimensions are in meters or feet unless otherwise noted. All slopes are in run-over-rise form (for example, 4 : 1) unless indicated as a percent slope with a “%” sign.
This section lists the parameters in this subassembly that can be mapped to one or more target objects, such as a surface, alignment, or profile object in a drawing. For more information, see in the AutoCAD Civil 3D User’s Guide Help.
| Parameter | Description | Status |
|---|---|---|
| Existing Surface | Existing Ground surface to connect sideslopes to. The following object types can be used as targets for specifying this surface: surfaces. | Required |
| Pipe Network 1 | Used to specify Pipe Network 1. The following object types can be used as targets for specifying this pipe network: pipe networks. | Required |
| Pipe Network 2 | Used to Specify Pipe Network 2. The following object types can be used as targets for specifying this pipe network: pipe networks. | Optional |
In both cases, the subassembly will determine the bottom of the trench depth and the trench width based on the location of a pipe (or pipes) in a specified pipe network. The Special Backfill Minimum Cover is determined by measuring the distance from the centerline of the highest pipe found at the sampled section. The Special Backfill Minimum Depth is determined by measuring the distance from the bottom outer diameter of the lowest pipe found at the sampled station.
Case 1: Single Pipe Network Selected
If only Pipe Network 1 is selected, the subassembly will search 3 feet (1m) from the controlling baseline to the left and right to find the pipe center line at the sampled station. Apply the Pipe Network 1 offset value to both sides to determine the trench width, or the minimum width, whichever is larger. The bottom of the trench is determined by the outer pipe diameter, plus the Special Backfill Minimum Depth, plus the Bedding Depth.
Case2: Two Pipe Networks Selected
When two pipe networks are selected, Pipe Network 1 will be assumed to be on the left side of the baseline. Pipe network 2 will be assumed to be on the right side of the alignment. The material depth of the Special Backfill Minimum Depth is determined by the higher of the two pipe outer diameters, plus the Special Backfill Minimum Cover depth. The bottom of the trench depth is determined by the lower of the two pipe outer diameters, plus the Special Backfill Minimum Depth, plus the Bedding Depth.
The following table lists the point, link, and shape codes for this subassembly that have codes assigned to them. Point, link, or shape codes for this subassembly that do not have codes assigned are not included in this table.
| Point/Link | Codes | Description |
|---|---|---|
| P1, P2 | Trench_Bottom | |
| P3, P4 | Trench_Daylight | |
| P5, P6 | Trench_Bedding | |
| P7, P8 | Trench_Backfill | |
| L1 - L7 | Trench Datum | |
| L8 | Trench_Backfill | |
| L9 | Trench_Bedding | |
| S1 | Trench_Bedding | |
| S2 | Trench_Backfill |
