Application range of anchor technology

Anchor rods (also known as earth anchors and soil nails) are the most basic component of roadway support in contemporary coal mines, reinforcing the roadway rock together so that the rock surroundings support themselves. Nowadays, anchors are used not only in mines, but also in engineering technologies to reinforce the main body of slopes, tunnels and dams.

As a technical means of technological and economic superiority, anchoring technology is more and more widely used in various engineering fields. At present, it is not onlywidely used in the world's major coal-producing countries, but also widely used in metallurgy, water conservancy and hydropower, railways and highways, military and construction projects. Anchor bolt support has both support and reinforcement. Compared with the usual way to maintain the stability of the structure by the action of gravity, it has many more distinct characteristics: 

1. After the excavation of the rock mass and soil mass, it provides supporting force, which plays an obvious role in protecting the strength of the rock and soil mass, controlling the further expansion of the deformation of the rock and soil mass and improving the safety of the entire construction process;

2. can effectively improve the original stress state of rock and soil body, so as to further improve the stability of rock and soil body;

3.  It can effectively strengthen the shear strength of the weak structural plane of the rock and soil body, thereby improving the mechanical properties of other aspects of the rock and soil body;

4. The structure and the rock and soil body are closely acted together to form a system that jointly resists external forces;

5.  The role of the anchor, density, structural parameters, direction and application time can be easily adjusted and set, so as to obtain the best stability with the least support force.

Nowadays, China's coal mine demand within a certain period of time will continue to maintain a stable rise, or even a rapid rise in the trend, in the face of the increase in coal mine demand, mining roadway conditions in all aspects are becoming more and more complex. In addition, the roadway will mostly have a rectangular fracture surface, which has a small bearing capacity, so the long time to protect the coal roadway column face is also very small. All the above factors lead to very difficult and complicated safety support for the roadway in the mining coal mine, and the requirements for support are also higher, and anchor support is undoubtedly a good solution to this technical problem.
Anchor rods are formed by drilling holes in the side walls of natural soil, placing tensioned rods, and grouting the anchor rods. According to the material used, the tensile rods can be divided into coarse steel bars, high-strength steel wire bundles, steel strands, etc. The cross-sectional area, number of layers, spacing and length of anchor rods on the sidewall are determined by calculation. The drilling diameter should be determined by design. The grouting in the hole is commonly used with cement mortar and concrete, which should be selected by the design and its ratio or strength grade should be determined, generally more cement mortar grouting is used. The drilling hole should be inclined downward at an angle of 15°~35°, as determined by the design. The grouting in the hole can be full or only a certain length of the anchor at the bottom of the hole, as determined by the design, and the grouting shall be done by pressure grouting according to the design pressure. When the design is multi-layer anchor, the construction of anchor is carried out when the first layer of anchor is excavated to the elevation of the first layer of anchor, and after the first layer of anchor is completed, the excavation is continued downward until all is completed. 

There are two methods of drilling: manual drilling and mechanical drilling. Formation. The tensioned rods can be divided into coarse steel bars, high-strength steel wire bundles, steel strands, etc. according to the materials used. The cross-sectional area, number of layers, spacing and length of anchor rods on the sidewall are determined by calculation. The drilling diameter should be determined by design. The grouting in the hole is commonly used with cement mortar and concrete, which should be selected by the design and its ratio or strength grade should be determined, generally more cement mortar grouting is used. The drilling hole should be inclined downward at an angle of 15°~35°, as determined by the design. The grouting in the hole can be full or only a certain length of the anchor at the bottom of the hole, as determined by the design, and the grouting shall be done by pressure grouting according to the design pressure. When the design is multi-layer anchor, the construction of anchor is carried out when the first layer of anchor is excavated to the elevation of the first layer of anchor, and after the first layer of anchor is completed, the excavation is continued downward until all is completed. There are two methods of drilling: manual drilling and mechanical drilling.