How Many types of rock bolts are there?

Time:2022-01-23From:sinorock View:

At present, there are many types of rock bolts used for geotechnical anchoring engineering support in China, including ordinary hollow anchors, self-drilling anchors, prestressed anchors, pressure anchors, hollow grouting anchors, and so on. In general, there are classification standards for bolts, but few people say it clearly. Today, Sinorock will give you a detailed introduction to the classification principles of bolts in the geotechnical engineering industry. What type does self-drilling rock bolt belong to?

Rock bolt classification method 1: according to whether it has the prestressing conditions

According to this principle, rock bolts can be divided into prestressed anchors and non-prestressed anchors. Trestressed anchors are further divided into prestressed anchors and low prestressed anchors. In the project of self-drilling bolt support, except for soil nails, which belong to non-prestressed bolts, other situations belong to low prestressed bolts.

Anchor bolt classification method 2: According to the type of force of the anchorage section of the prestressed bolt

According to this standard, bolts can be divided into tension bolts, pressure bolts, and tension-compression bolts. This classification standard is based on the prestressed anchor bolts, that is to say, whether it is a tension-type, a pressure type, or a tension-compression type anchor, they are all prestressed anchors. Self-drilling bolts provide anchoring force through the frictional resistance between the anchor and the rock and soil and are standard tension bolts.

Anchor classification method 3: according to the stratum where the anchor is located

The classification of bolts under this category is mainly determined by the geological structure, namely rock bolts, coated bolts, and rock-soil bolts. Since self-drilling bolts are particularly suitable for use in broken strata, such as sandy soil layers, siltstone, cobblestone geology, etc., self-drilling bolts can be any of them.

Anchor bolt classification method 4: by cementing material

According to the cementing material, the bolts can be divided into grouting bolts, resin bolts, cement roll bolts, cement-soil bolts, and cement-soil grouting bolts; cement-soil bolts can be divided into rotary bolts according to the construction process. Shotcrete anchor rod, rotary jetting mixing anchor rod, mixing anchor rod, and self-drilling anchor rod.

The self-drilling rock bolt body is made of thick-walled seamless steel pipe, with continuous standard threads throughout the body, which can be cut at any position or lengthened by connecting sleeves to meet the design requirements, and the connecting sleeves used for connecting the bolts must be connected with the anchor bolts. The strength of the rod body is the same, otherwise, it will have a certain impact on the tensile strength and yield strength of the self-drilling bolt.

Self-drilling bolts are classified as tensile low-prestressed rock-soil concrete bolts. They have been widely used in foreign countries and have very mature application technology. However, in the domestic market, the understanding of self-drilling bolts is only superficial, and there is no in-depth research and application. Sinorock believes that shortly, self-drilling rock bolt support will be able to replace the current ordinary bolt support and casing support, and become the first choice for engineering support.

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