Mining rock bolts refer to the cables used to secure the main cables to the side holes of a suspension bridge. The main cables are divided into multiple steel strands, each attached to an anchor block, forming the rock bolts. The anchor lines are fixed to the slope at the outer end and to the stable rock mass within the sliding surface at the other end. The prestressed steel strands on the slope sliding surface directly generate sliding resistance on the sliding surface, increasing sliding friction resistance, tightening the structural surface, and improving the integrity of the slope bedrock. This fundamentally improves the mechanical properties of the bedrock, effectively controlling bedrock displacement, and enhancing safety.

　　How are mining rock bolts installed?

　　Before installing the anchor cable on the anchor hole, ensure the anchor cable number matches the hole number. After confirming there are no errors, use high-pressure air to clean the hole once before starting the anchor cable installation.

　　Setting downward-inclined anchor lines is relatively simple and presents no technical issues. When setting inclined and horizontal anchors, pay attention to the following four points: Based on the position, damage, and technical requirements of the stop ring and limit ring, replace them as needed. Check the position and patency of the vent pipe. Insert the anchor cable into the hole, and stop pushing once the stop ring reaches the end of the hole. Install the grouting pipe and one-way valve. After the anchor is in place, check again if the vent pipe is well-ventilated. If not, remove the anchor, resolve the issue, and then proceed.

　　Tension of Mining Rock Bolts

　　Before tightening the anchor cables, calibrate the tensioning equipment. During calibration, connect the jack, oil pipe, pressure gauge, and high-pressure pump. Repeat the method of using the jack's active force in the pressure gauge three times to obtain the average value, and plot a curve of jack output (KN) and pressure gauge-indicated pressure (MPa) as the basis for anchor cable tension. Because the initial starting pressure of domestic pressure gauges is not exactly the same, the pressure gauge number during calibration should be displayed on the calibration curve, and they cannot be exchanged during use. Recalibration is required if the pressure gauge is damaged or the jack is disassembled.

　　When the mining rock bolt anchor cable consists of a small number of steel strands, a full-grade tensioning procedure can be used, with a stabilization time of 2-3 minutes at each stage. If the anchor cable consists of multiple steel strands, the assembly lengths are not exactly the same. To improve the uniformity of the force of each steel strand in the anchor cable, first use individual tensioning, followed by the entire compensation tensioning procedure after 3 days.

　　Grouting and Sealing of Mining Rock Bolts

　　Immediately after compensation tensioning, perform sealing grouting. For downward-inclined anchor cables, insert the main pipeline from the reserved hole until the nozzle enters the top surface of the anchoring section by about 50 centimeters. For upward-inclined and horizontal anchor cables, reserve the grouting pipeline for grouting. Air in the hole is discharged through the vent pipe set on the position stop ring.

　　External Protection of Mining Rock Bolts

　　To ensure quality and timely completion of construction tasks, a QC team should be established on-site. Scientific work methods should be consistently employed from beginning to end, with a series of countermeasures and implementation methods developed, the anchoring structure improved in a timely manner, construction processes actively refined, and advanced network technology used to organize construction, ensuring production is as balanced as possible. Ensure that drilling, grouting, tensioning, and sealing processes proceed in an interleaved manner without delays. Process:

　　Construction preparation for mining rock bolts - anchor hole drilling - anchor cable manufacturing - anchor hole grouting - construction of the waist beam (anchor, anchor or cross, steel base) - compression of the concrete filling between the waist beam and the pile - anchor hole tension lock - acceptance seal. There are two main construction processes: one is the anchor becoming a hole, and the core of the anchor hole drilling technology is how to prevent the collapse of the hole wall and drilling. The other is the grouting of the mining rock bolt anchor hole. The technical key to grouting is to discharge the air, rock (soil) debris, and groundwater at the bottom of the hole to the outside, so that the grouting fills the hole.