Article

The RocSlope2 Playbook: 6 Best Practices for Rock Slope Stability Analysis

Published on: Mar 17, 2025 Updated on: Mar 17, 2025 Read: 7 minutes

RocSlope2 streamlines rock slope stability analysis by combining multiple failure modes into a single tool. Whether you're transitioning from SWedge, RocPlane, or RocTopple, or already use RocSlope2 and want to refine your approach, these expert-backed best practices from Yalin Dogan (Application Engineer, Rocscience) will help you save time and optimize support design for any rock slope project.

1. Speed Up Your Workflow by Importing Existing Models

If you’ve previously worked with SWedge, RocPlane, or RocTopple, don’t waste time rebuilding your models in RocSlope2. Importing your existing models correctly ensures consistency and saves effort.

How to Do This:

Read existing SWedge, RocPlane and RocTopple project files into RocSlope2 to instantly produce the same geometry and input parameters as the original programs.
Once imported, review the model and compare it with your previous software to verify that the model assumptions were correctly transferred.
Due to RocSlope2’s advanced assumptions, such as groundwater pressure modelling and bolt pattern applications, an imported model may have slight differences. Use these features and assumptions to carry out your analysis.

2. Use the Stereonet View to Identify Key Structural Trends

When working with large datasets, raw joint measurements can be overwhelming. Instead of manually searching for structural patterns, use the Stereonet View to visually interpret how discontinuities relate to slope orientation.

How to Do This:

After defining your slope geometry and joint orientations, go to Stereonet View to view the stereographic projection of your planes to identify clustering patterns that may indicate dominant failure modes quickly.
Look for intersections between slope and joint planes — these can reveal potential sliding surfaces.
Regularly check stereonets as you refine your model to ensure that failure assumptions are well-supported by the data.

Figure 1. The Stereonet and All Analysis views tiled together, where you can simultaneously view the stereographic projections of the selected wedge, planar, and toppling blocks.

3. Incorporate Water Pressures to Improve Your Analysis

Water significantly impacts slope stability, but failing to model it properly can lead to overly conservative or underestimated risks. Rather than treating water pressure as a secondary consideration, make it an essential part of your analysis.

How to Do This:

Add water pressures to the models using flexible water pressure modelling options if you would like to analyze the influence of groundwater and/or ponded water on the analysis.
Use both groundwater and ponded water models together if applicable. This way, you can model the combined effects of both pressures at the same time.
Enable ‘Show Water Contours’ to visualize water pressure distribution along the associated joint planes or slope surfaces. If contours show unexpected water pressure zones, refine your groundwater assumptions.
Test different water levels as a sensitivity analysis to understand how changes in hydrogeological conditions affect stability.

rocslope2 water pressure contours — Figure 2. Water pressure contours showing the exerted groundwater and ponded water pressure distributions for each analysis mode.

4. Adjust Block Sizes to Reflect Real-World Stability Risks

By default, RocSlope2 looks for the maximum sized blocks to form for given slope configurations and joint orientations. However, an important aspect of dealing with the stability of wedge and planar blocks is the possible formation of smaller sized blocks because of the distribution of joint traces on the slope surface.

Instead of using the default block sizes, actively scale blocks based on field observations or expected conditions to analyze the effect of different block sizes on block stability and failure potential.

How to Do This:

If you have field measurement data and observations, adjust block scaling to match measured trace lengths, joint persistence or block sizes. If no field data is available, test different block sizes to determine which ones are most prone to failure.
Use this information to refine your support design — larger unstable blocks may require additional bolting or mesh reinforcement.

rocslope2 scale block dialog — Figure 3. The Scale Block dialog, which will present options for the current block and Analysis Method parameters. This example shows Wedge Analysis.

5. Filter Out Unnecessary Failure Modes to Stay Focused

When analyzing multiple failure scenarios, it’s easy to get overwhelmed by excessive data. Instead of reviewing every possible failure mode or valid block, use filters to focus on the most relevant ones.

How to Do This:

Select the relevant sliding conditions and block failure modes you would like to focus on – are you allowing the wedge blocks to slide on both joints, only Joint 1 or only Joint 2? Or are you enabling the wedge or planar blocks to lose contact with the joint planes due to external forces?
Use Failure Mode filters to exclude results that don’t match your specific focus.
After running the analysis, filter the blocks viewed in the Results Grid panel to focus on more critical blocks in terms of safety factor or block size.

rocslope2 failure mode filter — Figure 4. The Failure Mode Filter dialog, which will present options for filtering wedge and planar analysis based on various failure modes.

6. Use Sensitivity and Probabilistic Analyses to Understand Risks

Slope stability isn’t just about one deterministic result — you need to understand how input parameter uncertainties affect your safety factors and analysis results. Instead of relying on single-value inputs, use Sensitivity and Probabilistic Analysis to account for real-world variability.

How to Do This:

For Sensitivity Analysis:
- Vary the selected model input parameters across a range of values to observe their effect on factor of safety.
- Systematically adjust input parameters (e.g., slope and joint orientations, joint friction angle, cohesion) to see which factors impact stability the most.
- Quantify risks and determine safe design margins - If a small change in a parameter drastically shifts your safety factor, it indicates high sensitivity to the specific parameter and the need for more focus to improve analysis reliability.

rocslope2 Multi-Variable Sensitivity Plot — Figure 5. The Multi-Variable Sensitivity Plot for a wedge block, which plots the safety factor against the change in the Joint 1 and Joint 2 Dip values. In this example, the Factor of Safety is more sensitive to Joint 1 Dip.

For Probabilistic Analysis:
- Instead of entering single deterministic values, define statistical distributions for input parameters like rock mass strength and joint friction to account for parameter variability and uncertainty.
- Review probability distributions of failure outcomes to understand the likelihood of unsafe conditions.
- Use this analysis to meet regulatory safety standards and ensure your designs have sufficient risk buffers.

rocslope2 Planar Failure Probabilistic Analysis — Figure 6. An example of Planar Failure Probabilistic Analysis results tiled together with a scatter plot of Failure Plane Angle° vs. FoS.

Final Takeaways: How to Get the Best Results in RocSlope2

Implement these best practices and you’ll start making more strategic, data-driven decisions in your rock slope stability analysis. Here’s a recap of the key actions to take:

Import models smartly to avoid redundant work and leverage advanced analysis tools.
Use stereonets to visually interpret the geometrical relationship between slope orientation joints.
Incorporate realistic water pressures to better understand their impact on stability.
Adjust block sizes based on field measurements and observations to refine failure risk assessments.
Apply various filters, such as Failure Mode Filters or Block Results Filters, to avoid unnecessary distractions and improve analysis efficiency.
Run Sensitivity and Probabilistic Analysis to factor input data variability and uncertainties and meet safety standards.

These steps will help you get more accurate results, make better engineering decisions, and optimize slope designs with RocSlope2. Start integrating them into your workflow today!