New Technique and Application for Slope Reinforcement

With the rapid development of infrastructure, the management of geological disasters such as slope collapse and landslide of high apprentice faces new challenges. Therefore, the research and application of slope support and reinforcement treatment technology have social significance and economic value.

There are various slope protection technologies, generally, the combination of shotcrete-on-mesh and the geotechnical anchorage is mostly used. The self-drilling hollow anchor bolt is a new technology developed rapidly in recent years, which can meet the design anchorage force of 50Kn~1500Kn in tension and compression. Self-drilling hollow bars have been popularized and applied in various protection projects with good development prospects.

 

Design Elements of Self-drilling Hollow Bars

1. Anchor length

i.e. the total length required for the effective action of the hollow bars, calculated as the sum of the anchorage length, reinforcement length and exposed length according to the suspension action.

2. Anchorage length

The length of the hollow bars is anchored into the stable lower layer, which can be selected by experience or calculation. When calculating the length, the bonding force of mortar to hollow bars and the bonding force of mortar to hole wall shall be considered.

3. Reinforcement length

It is calculated by the height of the dangerous rock or the height of the surrounding rock load suspended along the direction of the hollow bar, and can also be determined by measuring the thickness of the loosening circle by testing techniques such as an acoustic wave.

4. Anchor pull-out test

Determined by anchor pulling gauge or torque wrench.

 

Technical points of self-drilling hollow bars construction

The steps of self-drilling hollow bars construction are as follows

1.    Install the drill bit to the hollow bar

2. Drill to the design depth with the drill rig. Hollow bars extensions can be connected with couplers.

3. Remove the drilling rig and install the plug in the anchor hole at 25 cm from the drilling hole to seal it. In case of special conditions such as high grouting pressure or broken surrounding rocks, anchor sealer can also be used to seal the hole.

4. Connect the tail end of the anchor rod to the special grouting machine through the grouting quick coupling.

5. Start the grouting machine and stop when the grouting is full and the pressure reaches the requirement. The grouting pressure is determined by the parameters and the performance of the grouting machine.

6. Install the gasket and nut according to the design requirements.

 

Innovative points of self-drilling hollow bars for slope reinforcement

1. Drilling, grouting and anchoring are completed in one time. The hollow bar as a drilling rod does not need to be pulled out. And the hollow of the anchor rod can be used as a grouting channel, and grouting can be done from inside to outside. The process is simple and the construction is easy and fast.

2. The trinity of hollow bars makes it possible to form anchor holes and ensure the anchoring and grouting effect without the need for special means such as casing protection or pre-grouting when working in various geological conditions.

3. The self-drilling hollow bar has the feature of lengthening while drilling and can be cut and connected to lengthen at will, which can be applied to narrow construction space and realize the design requirements of reinforcing the surrounding rock with extra-long anchor rods.

4. The high-efficiency plug keeps the grouting pressure strong, fills the cracks, and consolidates the broken rock. The high-strength plate and nut can evenly transfer the stress from the deep surrounding rock to the surrounding rock of the cave wall to achieve the purpose of supporting the surrounding rock.

 

Summary

Sinorock has many years of experience in manufacturing self-drilling anchor bolts and other anchoring products. Welcome to visite our website: www.sinorockco.com. If you have any questions, welcome to contact us at: sinorock@sinorockco.com, we will reply as soon as possible.

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