Self-drilling Anchor Bolt Advantages and Application

Self-drilling Anchor Bolt Advantages and Application

With the development of the construction industry at home and abroad, the self-drilling anchor system, as the most important solution in the geotechnical anchorage engineering industry, has been widely used in various construction projects. This article systematically introduces the application and advantages of self-drilling anchor bolts.

The Characteristics of Self-drilling Anchor Bolt

1.    Grouting and anchoring are completed at one time. The hollow anchor bar, which is used as drill rod also, does not need to be pulled out, and the grouting is carried out from inside to outside. The whole process is simple and the construction is convenient and fast.

2.    Three in one function in the construction of various surrounding rock conditions, without casing or pre-grouting and other special ways, can form anchor holes, to ensure the effect of anchorage and grouting.

3.    The hollow anchor bar can be cut anywhere and lengthened by the coupler, so it can be applied to the relatively narrow construction space.

4. High-pressure grouting makes it possible to fully fill the gap and

consolidate the broken rock mass. The high-strength plate and nut can transfer the stress of the deep surrounding rock to the wall rock evenly, so as to support the surrounding rock.

Advantages of self-drilling bolt

1. Suitable for all kinds of geotechnical conditions. SDA bolt has a better construction effect than those of common anchor bars, especially is used in complex geological conditions, such as easy-to-collapse geology.

2. Unlimited drilling depth. Due to the limitations of existing rock bolt materials and drilling equipment, the conventional rock bolt has a relatively shallow drilling depth, but the self-drilling rock bolt can drill deeper due to its small drilling resistance.

3. Suitable for construction in narrow spaces. The length of the single bolt can be cut or extended as required. Common specifications are 2m, 3m, 4m, and 6m.

4. Simple construction process. The self-drilling bolt can complete the drilling, grouting, and anchoring in one drilling, simplify the technological process and accelerate the construction speed.

5. It helps stabilize the hole wall. When drilling, the screw grouting machine is used to supply cement grout with a water-cement ratio of 0.4~0.5 under pressure, so that the grout can quickly fill the borehole and the rock and soil mass, and be absorbed and solidified by the hole wall to ensure the stability.

 

Construction Key Points

The construction steps of the self-drilling bolt are as follows:

1.     Preparation

It is necessary to fully understand the surrounding situation of the project and grasp the influence of surrounding buildings and stratum properties on anchorage construction;

Know about the condition of buried objects and obstacles;

State and quality of groundwater. A large amount of water is needed in the process of borehole grouting. It is necessary to consider whether the groundwater can be used and whether it will affect the construction process.

Check whether the drill rig is good to work, whether the bit and bolt body are damaged, etc.

 

2.     Simultaneous drilling and grouting.

The hollow anchor bar and the grouting pipe are connected with the drill rig through the rotary grouting adapter, and the grouting is carried out in the process of drilling to achieve the synchronous completion of drilling and grouting.

 

3.     Lengthen the hollow anchor bar

If the length of a single hollow anchor bolt cannot reach the required drilling depth, the coupler can be used to lengthen to meet the requirements.

 

4.    Install the flat plate and nut.

 

Summary

The practice shows that the construction efficiency of the self-drilling bolt is more than 30% higher than that of the traditional grouting anchor bolt. Self-drilling anchorage technology has brought great convenience to the control of disastrous geological conditions, and has been widely used in slope support, foundation engineering, tunnel and underground engineering, etc., exerting the irreplaceable effect of other anchorage materials.

Sinorock has 19 years of anchoring experience and has developed self-drilling anchoring systems that have been used in a wide range of slope engineering projects. Sinorock has a professional technical team, which can provide customers with application technical consultation and systematic solutions based on different geological conditions, application environments, and structures, to help customers improve construction efficiency and reduce comprehensive construction costs. Please contact: sinorock@sinorockco.com for a free quote.