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Home > News > Industry Information > 4 Key Features of Self Drilling Rock Bolt
4 Key Features of Self Drilling Rock Bolt

There are many technical parameters of self-drilling hollow rock bolts, and the models and specifications of self-drilling rock anchors used in different construction projects are also different. What are the technical parameters of self-drilling hollow bars?

First of all, let's take a look at what is a self-drilling bolts. Self-drilling rock bolt is a high-efficiency supporting material that integrates the three functions of drilling, grouting and anchoring. It consists of six parts, namely hollow bolt body, drill bit, connecting sleeve, backing plate, nut and centralizer. The anchor bolt body is hollow and can be used as a grouting channel. After connecting with the grouting machine, grouting can be carried out while drilling, eliminating the need for the traditional support method of first drilling and then inserting the bolt and finally grouting. The complex construction steps are directly completed in one step. After the slurry solidifies, the backing plate and the nut are installed close to the surface of the rock mass, and the stress is transferred to the surface of the rock mass, thereby supporting the loose, broken and unstable rock mass.

Sinorock self drilling rock bolt

Thread Type

Self-drilling rock bolts are divided into two types according to thread types, R type and T type. The thread of the R-type self-drilling bolt is continuous corrugated, and each thread of the T-type self-drilling bolt is an irregular trapezoid.

R thread self-drilling anchor bolts can be divided into R25, R32, R38 and R51 according to the diameter of the hollow bolt body. Among them, R32 and R38 are often used in slope engineering and foundation and foundation engineering, while R51 is often used in tunnel advance support, it is used as an advanced tube shed.

T thread self-drilling rock anchors can also be divided into T30, T40, T52 and T76 according to their diameters, among which T52 and T76 are often used in tunnels and underground projects as self-drilling pipe sheds.


R thread self-drilling bolt and T thread self-drilling bolts are the same, with 2m, 3m, 4m and 6m respectively. If none of these lengths can meet the designed drilling depth, the long anchor rod can be shortened at any position, or several anchor rods can be lengthened with connecting sleeves. The construction is flexible and convenient, and the construction can be carried out in narrow space conditions.

different length of self drilling hollow bar

Ultimate Load and Yield Load

Different types and specifications of self-drilling hollow anchors have different two important parameters, tensile force and yield force. For example, the tensile strength and yield strength of R25 are 200kN and 150kN respectively, and the tensile strength and yield strength of T76 can reach 1900kN and 1500kN. Sinorock can also customize the production of self-drilling hollow rock bolts with a diameter of 200, which have greater tensile strength and yield force, and can meet the design requirements of some special buildings.

Because the functions of grouting and anchoring that can be completed in one drilling, self drilling rock bolt can solve the problems of easily collapsed holes and difficult to form holes in the drilling process. conditions, the application is more and more extensive.