Rock slopes behave independently of the strength of the intact rock. Engineering considerations such as discontinuities, groundwater, weathering, blast damage, excavation damage and slope angle can influence specific modes of failure.
Common geotechnical issues involve:
Mode of failure should be considered prior to choosing any type of reinforcement products. Products designed to retain small scale fragments will not stabilize a large scale planar slide.
Rock slope projects may require stabilization, rockfall protection or a combination of both.
| Function | Primary objective | Typical measures |
| Stabilization | Reduce the likelihood of rock detachment or slope movement | Scaling, rock bolts, dowels, anchors, anchored mesh, shotcrete, drainage or slope modification |
| Surface retention | Hold smaller loose fragments close to the slope face | Anchored mesh, welded mesh or shotcrete where designed |
| Rockfall control | Guide falling material toward a controlled collection area | Draped mesh or suspended net systems |
| Rockfall interception | Stop or absorb moving rock before it reaches the protected area | Energy-rated barriers, catch fences, rock sheds or engineered catchment systems |
Regular welded wire mesh should not be promoted as an impact-rated rockfall barrier unless the full system has been tested and certified for the specified impact energy.
Wanfeng provides reinforcement and surface-retention products that can be included in a slope-support system designed for a specific project.
Rock bolts, dowels and threaded anchor bars can traverse discontinuities to link unstable blocks to stronger rock masses. Bearing plates and steel straps can be used to spread bearing pressures on the slope face. Appropriately-selected mesh can help retain smaller rocks or be an element in a reinforced surface coating.
Project designs may also include integration with:
Such complementary measures are not to be referred to as Wanfeng products unless capability is established.
Intended Functions of the System
Components working together may provide:
Engineering Disclaimer
Final slope geometry, scaling, anchor location, orientation, length, spacing, load, bond zone, drainage, mesh capacity and rockfall- protection system should be designed or confirmed by qualified geotechnical, geological and structural engineers. Design should take into account geological mapping, discontinuity orientation, potential failure surfaces, groundwater conditions, seismic conditions, exposure to weather, construction access, location of protected assets and required design life. Wanfeng provides products to confirmed specifications and does not assume the responsibility of the project engineer’s slope-stability analysis or rockfall-hazard assessment.
1.Rock Bolts / Slope Reinforcement Bolts
Steel reinforcement elements that can be installed through joints or other discontinuities to restrain individual unstable blocks.
Important Specification Parameters
Other Specification Parameters
2. Fully Grouted Threaded Anchor Bars
Threaded steel bars designed for project specified grout or resin anchorage for use in rock slope reinforcement projects.
Important Specification Parameters
Other Specification Parameters
3. Rock Dowels
Untensioned reinforcement elements that can be specified to cross discontinuities and develop their resistance as the supported rock mass begins to deform or move.
Important Specification Parameters
Other Specification Parameters
Additional Information
Whether an element is designed to be a tensioned bolt, untensioned dowel or a prestressed anchor must be clearly stated on the approved engineering specification.
4. Long Anchors / Cable Reinforcement
Long reinforcement elements that may be considered where a potential failure surface extends beyond the reasonable length of conventional rock bolts.
Important Specification Parameters
Other Specification Parameters
Additional Information
Long or prestressed anchors will require project specific engineering design, load testing, detailing of anchorage method and corrosion protection. Cable bolts should not be automatically assumed to be directly equivalent to permanent geotechnical anchors.
5. Bearing Plates
Steel plates used to help transfer and distribute bolt or dowel loads against the slope surface.
Important Specification Parameters
Other Specification Parameters
Additional Information
The size, thickness and seating arrangement of the plate should relate to both the existing surface condition and the design load. Very weak or open and irregular collar zones may require engineered load distribution details to ensure local bearing stresses remain low.
6. Welded Wire Mesh
Steel mesh panels that may be used for local surface retention or as reinforcement within project specified shotcrete.
Important Specification Parameters
Other Specification Parameters
Additional Information
Welded wire mesh should not automatically be considered suitable for use in high energy rockfall interception applications. Its specific role and performance capacity must be clearly defined on the approved engineering design.
7. Steel Straps
Flat or profile steel components that may assist in distributing restraint between adjacent reinforcement elements.
Important Specification Parameters
Other Specification Parameters
8. Nuts, Couplers and Accessories
Coupling components that are matched to the specified thread, required anchorage arrangement and mechanical performance requirements.
Important Specification Parameters
Available configurations may include:
| Typical slope condition or failure mechanism | Typical requirement | Products or systems that may be relevant |
| Isolated loose block | Localized block restraint | Rock bolts or dowels with bearing plates |
| Planar sliding along a persistent joint | Reinforcement across the potential sliding plane | Engineered bolts, dowels or anchors |
| Wedge formed by intersecting joints | Reinforcement oriented across controlling discontinuities | Project-designed bolts or anchors |
| Toppling blocks | Restraint of rotation and separation | Engineered bolts or dowels with suitable surface connections |
| Closely fractured surface rock | Surface retention | Anchored mesh, welded mesh or shotcrete where designed |
| Ravelling of small fragments | Retention or controlled collection | Mesh system selected for the fragment size and slope geometry |
| Weak or weathered collar material | Wider surface load distribution | Suitable bearing plates, washers, straps or reinforced surface treatment |
| Deep potential failure surface | Reinforcement extending into stable material | Long bars or geotechnical anchors designed for the identified surface |
| Groundwater in discontinuities | Reduction of water pressure | Engineered horizontal drains and surface-water control |
| Wet or chemically aggressive environment | Corrosion resistance | Galvanized, coated or multi-layer protected components |
| Rockfall requiring controlled descent | Guide material toward a catchment area | Engineered draped or suspended mesh |
| Rockfall above a road or structure | Intercept moving blocks | Tested energy-rated barriers or protective structures |
| Erodible seam or localized weak zone | Surface protection and reinforcement | Shotcrete with mesh and bolts where designed |
| Seismic or dynamic loading | Verified deformation and energy capacity | Only components or complete systems with applicable test data |
| Long-term permanent stabilization | Durability, inspection and traceability | Products with verified long-term protection and documentation |
Design Note
This grid is meant as a preliminary guide only and does not constitute a slope design.
Bolts should be installed based on the geometry of the potential failure surface and not just in a uniform grid without consideration of the potential failure surface. Anchorage into resisting material is required.
Things to check by the project engineer include:
Wanfeng is able to review customer approved drawings and product schedules for manufacturability.
Customization options available include:
All material specifications, tolerances, loads, coatings, etc. must be verified against an approved drawing or technical specification prior to manufacturing.
Quality-control criteria listed below should be applied to the product, project specification and agreed inspection plan.
Raw Material Inspection :
Dimensional and Thread Inspection :
Mechanical and Load Testing :
(Yield strength / ultimate tensile strength / elongation / etc.)
Where applicable, may include contractually specified:
Weld Quality Inspection :
Surface Treatment Control :
Identification and Final Inspection :
Certificates and Test Reports :
Any certification or third-party test reports claimed should be published :
ASTM, EN, ISO, AS/ NZS or project standards should only be listed if that standard conforms to the specific product being supplied and the supply scope.
Rock slope elements may be exposed to rain, groundwater, salts, temperature fluctuations and atmospherically corroded. Consideration may need to be given to the following when assessing project durability:
It should be noted that the coating selected needs to be compatible with the bolt, nut, coupler, grout and installation method. Simply specifying galvanizing is not sufficient for every permanent anchor application.
Product performance will be determined by how well it is installed and the overall stabilization system.
Consideration should be given to the following items when preparing an approved work plan:
Maintenance Indicators
A properly designed inspection program may include checks for:
Frequency of inspections and necessary corrective actions should be clearly outlined by the asset owner and consulting engineer.
1. What products can be used to stabilize rock slopes?
Rock bolts, dowels, threaded anchors, bearing plates, mesh, steel straps, shotcrete, drainage and slope modification are just some of the tools that could be used as part of an engineered slope stabilization system. The correct combination will depend on the nature of the failure mechanism, and no single solution will be ideal for every rock slope.
2. How do rock bolts help stabilize a slope?
Rock bolts can traverse joints or potential sliding surfaces and link an unstable block to surrounding competent rock. If used correctly their strength and orientation can help constrain movement. Factors affecting performance include bolt length, orientation, anchorage, load capacity and installation quality.
3. What is the difference between a rock bolt and a rock dowel?
Rock bolts are typically tensioned to apply or maintain a known load. Untensioned dowels rely on movement to generate resistance within the ground. Language varies between projects so the required structural performance should be clearly specified rather than assumed based on naming.
4. Is welded wire mesh acceptable for rockfall mitigation?
If properly designed welded wire mesh may be suitable for small scale surface retention. However, high energy rockfall applications should not expect welded wire to reliably absorb impact energy. Both energy-rated barriers and flexible rockfall mitigations require testing of the complete system.
5. What is anchored mesh vs draped mesh?
In anchored mesh applications mesh is fixed to the slope and may assist in holding material close to the rockface. Draped mesh does not require slope fixation and is normally designed to direct falling debris into a collection zone. Both systems have different design functions and capacity requirements.
6. How should I select rock bolt length and orientation?
Orientation and length should be selected based on geological analysis of the structure, discontinuities or expected sliding surface. Consideration should be given to ensuring the reinforcement can extend far enough into stable material to develop the required strength.
7. Why is drainage important for rock slope reinforcement?
The presence of water can increase pressures within fractures, reduce the effective strength along potential sliding surfaces, or encourage weathering. Drainage should therefore be considered where possible, but care should be taken to design solutions that are suitable for each individual slope.
8. Can Wanfeng produce reinforcement from slope-support drawings?
Yes, approved slope-support drawings can be reviewed for availability of materials, specific dimensions, threads, load capacities, coatings, required testing and feasibility of production. Production should only commence after receiving technical confirmation from Wanfeng.
