Due to the development of fault folds in the underground mining area of gold mines, the stratum is broken. The fault zone is essentially a strong tectonic strain zone and a strong mineralization alteration zone. The split set rock bolts in this area are strongly deformed. The ore bodies and surrounding rocks of the roof and floor are mainly thin to medium-thick sandstone and thin claystone. The clay rock is very soft and broken, and will soften and produce silt when it meets water. Therefore, when the underground mine first started to excavate the main slope, the support method adopted was pipe joint bolts and steel mesh. The wall thickness of the pipe joint anchor rod is 3mm, the straight length is >47.5mm, the length is 2.4m, and the slit width is 15mm.
Slotted bolt support has many advantages, such as easy installation, timely provision of supporting resistance, and the bolt does not lose its supporting resistance when the surrounding rock is significantly displaced, but there are also some problems, including low anchoring force; The hole diameter requirements are strict, the hole diameter is too large, and the anchoring force is low; the hole diameter is too small, the split set rock bolts is easy to bend, it is difficult to enter the hole completely, the anchoring depth is reduced, and the anchoring force is reduced; the anchor rod is in contact with air, and it is easy to oxidize and rust. Especially in roadways with larger groundwater, the bolts will corrode faster and more severely. Due to the above shortcomings of the slotted bolt, its reliability when used in roadway roof support and sexual roadway support is very poor.
The resin anchor rod is used together with the rod body and its accessories of different strength materials and the supporting resin anchoring agent. According to the designed anchoring length, the rod body is inserted into the drilled hole. After stirring, the anchoring agent produces a chemical reaction. Within a certain period of time, Glue the split set rock bolts body and the rock mass into one body. After waiting for the installation time, install the tray on the threaded end and tighten the nut to apply a certain pre-tightening force to the surrounding rock to make the surrounding rock in a three-dimensional stress state, which improves the stress state of the surrounding rock and makes the surrounding rock The strength of the roadway is improved, which can strengthen the surrounding rock and prevent it from moving, thereby improving the integrity and stability of the roadway.
Specifically, the split set rock bolts supports and strengthens the surrounding rock through the functions of "suspension, composite beams, and compression-reinforced arches."
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