Homework - Reinforced Slope Design
The following slope is similar to the geogrid problem we solved in class:
The objective of this assignment is to design a reinforced slope using geogrids that is both safe and economical. You will determine the number of geogrid layers, their elevations, and their lengths. Use XSLOPE to perform the slope stability analysis and to design the reinforcement.
The Excel input for this assignment has been prepared for you:
This file contains everything but the reinforcement table.
Use the following XSLOPE Google Colab notebook to perform the analysis and design:
(a) Slope analysis
Solve the problem assuming the slope does not have any reinforcement. Compute the critical factor of safety using a circular failure surface. Save a copy of your solution plot.
(b) Reinforcement design
Design reinforcement for the slope using layers of geogrids. You can add as many layers as you need (up to the limit of 10) and you can put them at any combination of elevations. Design a length for the layers, but keep each layer the same length in order to simplify the problem. In summary, you will have three basic design parameters:
- Number of layers
- Elevations for the layers
- Lateral length of the layers.
Assume the following parameters:
| Parameter | Value |
|---|---|
| Tensile strength | 800 lbs/ft |
| Pullout length | 4 ft |
| Cost/ft | $300 |
Your objective is to design a reinforcement that satisfies the following constraints:
- Minimize the total cost
- FS must be >= 1.5
The total cost is calculated as the sum of the unit cost multiplied by the number of layers and the layer length. Do your calculations in the reinforcement sheet of the Excel file below the table.
Save a copy of your solution plot corresponding to your final design. Make sure the table in the reinforcement sheet matches your final design.
Submission
Show all of your calculations inside the Excel input file on the "reinforce" sheet. Add the two plots and the Excel files to a zip archive and upload the archive to Learning Suite.
Grading Rubric
Total: 30 points
| Criteria | Points |
|---|---|
| Part A: Unreinforced slope FS calculation | 7 |
| Part B: Reinforcement design meets FS ≥ 1.5 | 9 |
| Part B: Design is economical (minimized cost) | 9 |
| Part B: Calculations for costs were done correctly | 5 |