What Is Ground Support? Mining & Tunneling Support Guide

What Does Ground Support Mean?

Ground support products are materials used to help support and stabilize rock, soil, and underground excavations. This includes things like bolts and straps, reinforcement meshes, anchors and monitoring tools.

Exactly which types of ground support you might need will depend on the conditions you’re working with and what you’re trying to support. A ground support system may consist of one or more of the following:

• Rock bolts & anchor bars
• Cable bolts
• Resin or cement
• Steel arches
• Steel straps
• Wire mesh/support
• Bearing plates, nuts, and other fastening hardware
• Drills and installation equipment

Keep in mind that ground support doesn’t always rely on just one of these elements. Many mines and tunnels utilize multiple support methods in combination.

A tunnel may be stabilized using rock bolts to support the rock mass, mesh to prevent loose rocks from falling onto workers, bearing plates to help distribute the load from the bolts, and steel arches to provide additional support where needed.

Because of this, it’s important to think of ground support as a complete system, instead of just a collection of parts.

View Wanfeng’s full line of ground support products.

Why Do We Need Ground Support Underground?

Excavating anything underground, be it a tunnel, mine roadway or underground chamber alters the natural stress distribution that existed within the rock mass.

Rock in place is typically restrained by the material around it. When part of that material is removed the stresses around that opening are allowed to redistribute.

During or after this stress redistribution the surrounding ground may experience:

* rock movement;

* cracking/joint opening;

* loose rock/falls from surfaces;

* roof deformation;

* sidewall instability;

* squeezing ground; or

* localized structural failure.

Ground support is utilized to control these conditions and stabilize the excavation.

When properly designed and installed, support helps create a safer environment allowing excavation, production and construction activities to continue safely. The correct support arrangement should be based on project geology, engineering design, anticipated loading conditions and installation requirements.

What Are the Main Types of Ground Support?

Every mine and tunnel is different. There’s no single ground support product that works best in all applications.

Tailored reinforcement. That’s why most modern ground support systems normally consist of a combination of components from several of the categories below.

1. Rock Bolting & Anchoring Systems

Rock bolts are some of the most commonly used ground support components in underground mines and tunnels.

Rock bolts don’t just prop up loose rock from below. When installed correctly, they reinforce the surrounding rock mass itself.

Depending on the scale and geotechnical conditions of the project, designers can specify different anchoring technologies including:

* resin anchored rock bolts

* hollow grouting anchor bars

* cable bolting systems

* mechanical bolts

* friction bolts

* threaded anchor systems

View Wanfeng’s rock bolting and anchoring systems for mining & tunneling projects.

Want to know how rock bolts work?

In most cases, the idea is to help connect unstable rock to adjacent rock that is more stable. The diagram below shows a simplified load-transfer mechanism:

Bolt / anchor bar → anchoring medium → bearing plate → nut / locking component

The installed reinforcement then works with the surrounding ground to provide stabilization, rather than acting alone as a separate structural element.

2. Resin & Cement Anchoring Materials

What connects the anchoring device to the ground? In many cases you’ll find resin cartridges or cementitious grout.

Resin anchoring

Resin cartridges are popular when rapid installation is required, along with fairly quick setting times.

To install, the anchoring resin is mixed inside the borehole as the bolt is inserted (often with some rotation applied). It creates a strong resin system that helps bond the bolt into place.

Cement grouting

Cement grout can also be used with hollow bars and other reinforcement techniques that need to fill and bond the drilled hole or surrounding ground.

Don’t think of these products as simple consumables. In most cases, they form a crucial part of the reinforcement load transfer design.

View our selection of grouting and anchoring materials.

3. Cable Bolting Systems

Need your reinforcement to penetrate deeper? Cable bolts can transfer loads to greater depths than traditional rock bolts.

Cable bolts have been used in:

• underground mines and tunnels
• large span excavations
• mine roofs
• underground chambers

As their name suggests, cable systems use longer strands of steel that can reach deeper into the ground. The exact design will vary based on the job requirements and geotechnical conditions.

Need help selecting cable bolts for your application?

Each cable bolt will normally consist of the strand (or cable), along with grout, anchor locks, plates and fasteners. For this reason, cable bolts should be specified based on the complete assembly, rather than simply diameter of the cable.

View rock bolting and anchoring systems for underground support.

4. Steel Support Systems

In conjunction with rock bolts, steel support helps strengthen the ground around an underground opening.

Steel support systems may consist of:

• U Steel Supports
• Steel Arches
• I-beams / structural beams
• W steel straps
• connecting / fixing components

Steel systems allow installers to enclose or “brace” an excavation with additional structural support. They can be especially useful where excavations require greater structural confinement, or where localized support alone won’t fully compensate for geological deformations.

Steel beam + rock bolt installations may look something like this:

Under some circumstances, excavations may use steel ribs together with rock bolts, mesh, straps and arches.

Discover different steel support systems for tunnels and mines.

5. Surface Support & Reinforcement

Just because you’ve installed bolts into the ground doesn’t mean fragments of rock will be unable to fall from the rock surface between bolts.

That’s why surface reinforcement is commonly installed in conjunction with rock bolts and cables.

Mesh helps prevent loose rock fragments from falling between anchor points. Plates distribute loads from the rock surface to the installed bolt.

Surface support systems can include:

• wire mesh
• reinforcement mesh
• steel straps
• bearing plates
• domed plates
• butterfly anchor plates
• nuts / washers
• fasteners / accessories

Together, these components may form a ground support system that looks like this:

Rock mass → mesh → bearing plate → rock bolt → anchored ground

Browse surface support and reinforcement materials.

6. Drilling & Cutting Tools

Rock reinforcement is only as strong as your installation method. Before most ground support systems can be installed, holes need to be drilled into the ground.

Mining/drilling conditions will vary based on the application. Some of the more common variables include:

• hardness of the rock
• abrasiveness
• hole diameter
• required drilling depth
• drill equipment
• bolt/anchor specs

Installers will also require compatible drilling bits and cutting tools to create the anchor holes. Browse Wanfeng’s range of drilling tools for mining and tunneling.

Active Support vs Passive Support: What’s the Difference?

Headed titles sometimes refer to ground support systems as either active or passive support.

Active reinforcement

An active support system has interaction with, or reinforces, the surrounding rock mass.

Rock bolts and anchored support would fall under this category as their intended function is to enhance the performance of the rock mass surrounding the excavation.

Passive support

Systems considered passive usually react by providing resistance against ground movement or loading of the support system.

Steel Arches and some structural support systems can fulfill this function dependent upon design.

Most underground support systems will utilize a combination of both concepts.

Hybrid Support Example:

Rock bolts for reinforcement > mesh to control loose rock fall > steel arches for structural support.

Determining active vs passive support isn’t always the goal, but instead finding the right balance to suit ground conditions.

How Do You Choose a Ground Support System?

Rather than looking through a product catalog first, ground support selection should be based off of engineering requirements. There are a number of factors that should be addressed.

Rock Mass Conditions

Questions to ask may include:

• Does the rock appear to be competent or very fractured?
• Does the rock mass contain major joints or other discontinuities?
• Is the ground squeezing/arching/deformable?
• Are you dealing with groundwater?
• Are the ground conditions highly weathered?
• Is there weak layers in between stronger rock layers?

Rock mass conditions can help determine what type of reinforcement action will be needed, as well as help define support density.

Excavation Geometry

A small mine tunnel will not typically use the same support as a large underground cavern.

Parameters commonly taken into account include:

• excavation width
• height
• span
• depth
• orientation
• roof and sidewall rock conditions

Typically larger excavations will require longer or deeper reinforcement and incorporate elements such as cable bolting or structural steel supports.

Required Anchor Length and Load

Selection of bolts should be based on more than simply increasing the diameter of the rebar.

• Length of anchor
• Breakout strength
• Yield strength
• Plate size
• Method of anchorment
• Installation pattern

Should be considered to match the engineering design.

Using hollow grouting anchors as an example, various anchor lengths may be used to satisfy different reinforcement requirements.

Wanfeng offers multiple hollow anchor bar configurations within their rock bolting and anchoring system. Different hollow bar sizes are available to meet project specific needs.

Installation Conditions

The proper equipment must also be available to install the support system.

Projects should take into consideration:

• what drilling equipment is available
• size of borehole
• installation space
• bolt installation equipment
• grouting method
• access limitations
• construction sequence.

Installation access can be very limited in underground mines so this is key to consider.

Corrosion/Service Environment

In environments with groundwater, humidity or exposure to chemicals can affect steel elements and their durability.

Projects should evaluate environment when selecting materials and coatings if long-term service is required. These should be specified when discussing the project with your support supplier.

Typical Ground Support Configurations

The following configurations would be designed by certified engineers, but they provide examples of how different components work together in various applications.

Underground Mine Roadway

Possible configuration options include:

Rock bolts + resin anchoring + bearing plates + steel straps + mesh

This system uses bolts to help stabilize ground surrounding the excavation. Mesh and straps are installed at the surface to help prevent falls of ground.

Tunnel Construction

Likely components of a tunnel support system include:

Rock bolts + grouting + mesh + steel arches

The final system would depend heavily on geology, size of tunnel and the method of excavation.

Wanfeng has provided products for tunnel reinforcement and worked on ground support projects involving tunnels. Projects include the Hong Kong Shatin to Central Link SCL 1103 Tunnel Support Project and the 4,392 m Xia Gongla Mountain Tunnel Construction Project in Tibet. Visit our project cases to read about previous projects.

Open-Pit Mine and Quarry Highwall

Ground support applies to excavations above ground too.

Anyplace where there are natural or man-made weaknesses in rock faces may require some sort of reinforcement. That includes highwalls in open pits and quarries.

Support may include one or more of the following elements:

• anchor bars
• rock bolts
• mesh
• plates
• grouting material
• additional slope reinforcement solutions

Learn more about Wanfeng’s open pit mine and quarry highwall support.

Highway and Cut Slope Reinforcement

Projects to help stabilize soil and rock cut-slopes along transportation routes may use ground anchors.

An anchor system may be used with surface reinforcements, drainage or other engineering techniques based on the project conditions.

View Wanfeng’s highway embankment and cut slope support solutions.

Ground Support Systems Are Made of Many Components

If you are in charge of purchasing ground support hardware, you should know that the products you use do not work individually.

Take for example this theoretical bolted mine roof:

The bolt is the primary reinforcement element.

Resin or grout helps transfer loads between the bolt and ground.

The plate evenly distributes force along the excavation surface.

Mesh helps prevent rock falls at the surface.

The nut locks the system into place.

Steel straps may help connect different points of reinforcement.

Steel arches can be used to provide additional support if necessary.

Specifying a cheaper plate or sudden switch to another bolt size can lead to sourcing issues if the rest of the system is not compatible. We recommend reviewing entire support system when shopping for ground support hardware, especially for international mining projects.

Questions to Ask Before Ordering Ground Support Products

Providing your project information allows the manufacturer to suggest a more suitable product configuration.

Try to have the following information ready before asking for a quote:

1. What is the application?

Examples include:

• underground coal mine,
• hard-rock mine,
• railway tunnel,
• highway tunnel,
• hydropower tunnel,
• quarry highwall,
• highway slope,
• foundation excavation.

2. What support components are needed?

Indicate if the project requires:

• rock bolts,
• cable bolts,
• anchor bars,
• resin cartridges,
• cement grout,
• steel arches,
• mesh,
• plates,
• nuts,
• drilling tools.

3. What specifications are needed?

Provide known engineering requirements like:

• diameter,
• length,
• thread type,
• steel grade,
• tensile strength,
• plate size,
• hole diameter,
• anchoring length,
• corrosion protection.

4. What quantity is needed?

Estimated yearly or project quantities allow larger mining projects to better plan production scheduling and packaging with the manufacturer.

5. Are project drawings available?

Provide as-built or engineering drawings when available. Technical drawings allow the manufacturer to better assist with customized components, special dimensions, or combination support assemblies.

One Stop Ground Support Supply for Mining & Tunneling Projects

Coordinating numerous suppliers can become a challenge when you have bolts, anchors, plates, mesh, structural steel components and drilling supplies being delivered at the same job site.

Partnering with a supplier that can provide a full line of compatible ground support supplies can make it easier to manage:

• specifications,
• compatible products,
• quality standards,
• packaging,
• combined shipments,
• purchase order communication.

Hebei Wanfeng Machinery Manufacturing Co., Ltd. is a manufacturer and exporter of mining and engineering support products. It has supplied ground support for mining projects, tunneling, underground construction, slope stabilization, foundation support and reinforcement.

Its ground support product lines include:

• grouting and anchoring materials,
• drilling and cutting tools,
• rock bolting and rock anchoring systems,
• steel support systems,
• surface support materials and reinforcement supplies.

Wanfeng can also assist with custom dimensions, combined support equipment or private labeling through its Ground Support Engineering and OEM Services.

FAQ

1. Q: What is ground support?

A: Ground support refers to components used to reinforce or support the roof, sidewalls and adjacent rock of underground excavations. This includes rock bolts, cable bolts, resin or grout, wire mesh, steel straps, bearing plates and steel structural supports.

2. Q: What is the difference between a rock bolt and a cable bolt?

A: Rock bolts are generally used to provide localized reinforcement to rock near an excavation. Cable bolts, made of flexible steel strands, allow for deeper reinforcement where greater length is needed for anchoring.

3. Q: Why would wire mesh be used alongside rock bolts?

A: Rock bolts are used to help reinforce specific points in the rock mass while mesh is used to help retain smaller pieces of rock between these larger points of reinforcement. Using mesh with rock bolts can therefore help to prevent rock falls.

4. Q: What does resin anchoring do?

A: Resin materials are often used to anchor rock bolts into place within a borehole. Fast-setting resin allows for quicker anchoring while underground.

5. Q: When are steel arches used?

A: Steel arches can provide additional structure support and confinement to an excavation that cannot be provided by localized rock reinforcement. The spacing and sizing of the arches should correspond with the designed tunnel dimensions and surrounding geological conditions.

6. Q: Can I use the same ground support in every mine?

A: Ground support should be selected based on geological conditions, rock mass behavior, size of excavation, depth, anticipated loading conditions, groundwater conditions and desired service life.

7. Q: What information should I give a ground support supplier?

A: Project type, drawings, dimensions of bolt/anchor, load/material properties required, plate size, thread, corrosion requirements, quantities and installation conditions are all useful information to provide when seeking a ground support supplier.

Need Rock Bolts and Ground Support for your Project?

Whether you’re starting up an underground mine or tunnel, quarrying for stone, stabilizing slopes or reinforcing foundations – there are ground support products designed for your project.

At Wanfeng, we provide project based supplies of rock bolts, anchor bars, cable systems, steel supports, mesh, plates, anchoring materials and drill tools. Send us your drawings, specifications, quantities needed and application and we’ll supply you with a project based ground support solution.

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