Self-drilling Hollow Grouting Rock Bolt

Product Overview

Self-drilling hollow grouting rock bolt is a new type of support material integrating drilling, grouting and anchoring functions, widely used in geotechnical engineering fields such as tunnels, mines, slopes and foundation pits. Featuring a hollow threaded design, the bolt body serves as a grouting channel, enabling simultaneous drilling and grouting construction, which effectively solves engineering problems of traditional rock bolts such as difficult hole formation and insufficient grouting.

Manufactured from high-strength alloy structural steel with anti-rust surface treatment, the product delivers excellent tensile strength and corrosion resistance. Equipped with dedicated drill bits, bearing plates, nuts and grouting stoppers, it enables rapid installation and efficient anchoring, making it an ideal choice for support and reinforcement in weak surrounding rock, fractured strata and high-stress conditions.

Core Advantages

Multi-function in One Drill, Efficient Construction

Integrates drilling, grouting and anchoring functions in one unit. Grouting can be completed without withdrawing the drill rod, significantly shortening the construction cycle and improving engineering efficiency.

Full Grouting, Reliable Anchoring

The hollow design ensures grout reaches the bottom of the hole through the bolt body, realizing pressure grouting from inside to outside, effectively filling surrounding rock fractures and forming a complete reinforced body with significantly improved anchoring force.

Adaptable to Complex Strata

Suitable for difficult-to-drill strata such as loose, fractured and weak formations. The self-drilling process avoids hole collapse risks and ensures hole quality and support effectiveness.

High Strength, Good Durability

The bolt body is made of high-quality alloy structural steel through heat treatment, featuring high tensile strength and good toughness. Surface anti-corrosion treatment effectively resists underground corrosive environments with long service life.

Easy Installation, Cost Saving

Complete accessories and simple operation, no large equipment required, reducing labor and machinery costs. Fast construction speed brings remarkable comprehensive economic benefits.

Product Specifications

Application Scenarios

Tunneling & Underground Engineering

Suitable for primary support and advance support of railway, highway tunnels and subway projects, especially excellent in complex geological conditions such as weak surrounding rock and fault fracture zones.

Mine Roadway Support

Widely used for roadway surrounding rock reinforcement in coal mines, metal mines and non-metal mines, effectively controlling surrounding rock deformation and ensuring underground operation safety.

Slope Reinforcement & Treatment

Used for reinforcement of highway and railway slopes and landslide treatment. Grouting anchorage improves overall slope stability and prevents rock and soil mass sliding.

Deep Foundation Pit Support

Serves as a core component of soil nailing walls or bolt support systems in deep foundation pit projects such as high-rise buildings and subway stations, providing reliable lateral resistance.

Water Conservancy & Hydropower Engineering

Applicable to surrounding rock reinforcement and anti-seepage treatment of dams, reservoirs and water conveyance tunnels, improving overall engineering safety factor.

Foundation Reinforcement

Used for foundation reinforcement of existing buildings, pile foundation underpinning and foundation strengthening, effectively improving foundation bearing capacity.

Structural Details

The self-drilling hollow grouting rock bolt consists of alloy drill bit, hollow threaded bolt body, grouting stopper, bearing plate, nut and coupling sleeve. The front-end cemented carbide drill bit is wear-resistant and efficient, with grout outlets at the end ensuring grout injection from the hole bottom. The middle hollow threaded bolt body serves as both grouting channel and anchoring force transmission, with continuous threads on the surface facilitating component connection and length adjustment. The hole-mouth grouting stopper prevents grout backflow and maintains stable grouting pressure. The bearing plate works with the nut to apply pre-tightening force, enabling the bolt to provide active support immediately. For deep-hole support, multiple bolts can be extended via coupling sleeves with connection strength no less than the bolt body itself.

FAQ

What is the difference between self-drilling rock bolts and ordinary rock bolts?
Ordinary rock bolts require three separate steps: drilling first, then inserting the bolt, and finally grouting. Self-drilling rock bolts combine drilling and grouting into one process — grouting can be done simultaneously while drilling, resulting in higher construction efficiency, especially suitable for weak and fractured strata with high hole collapse risks.

What is the recommended grouting pressure?
Conventional grouting pressure is recommended at 0.5~2.0MPa, which should be adjusted according to surrounding rock conditions, grout type and design requirements. Pressure can be appropriately increased in fractured strata to ensure grout fully penetrates and fills fractures.

How to select the bolt length?
Bolt length should be determined based on the thickness of the surrounding rock loose zone, design anchoring force and engineering requirements. Generally, tunnel primary support bolts are 3~6 meters long, and advance support bolts can be longer as needed. We provide professional technical support to assist with selection.

Can products be customized?
Yes. We support customized rock bolts of different specifications, lengths, materials and surface treatments, and can also provide complete support solution design according to special engineering requirements.

What supporting equipment is needed for construction?
Main supporting equipment includes rock bolt drill rigs, grouting pumps, mixers and corresponding drill rod connection tools. Specific configuration can be determined according to project scale and geological conditions.

Contact Us for Custom Solutions

With years of experience in geotechnical support product R&D and production, we are equipped with a professional technical team and complete production lines, providing comprehensive customized solutions tailored to your specific engineering needs. Whether your project involves tunneling, mine construction, slope treatment or foundation pit support, we can create the most suitable product configuration and construction plan for you.