The construction process of the expansion shell anchor rod is: anchor hole ventilation inspection → drilling → inserting the hollow anchor rod → pre-tightening the rod body → installing the stop plug, backing plate, nut → tensioning → grouting.

　　(1) Drill forming and thoroughly clean the hole.

　　(2) Insert the rod body with the expansion shell anchor head directly into the bottom of the hole. If the anchor rod needs to be lengthened, it can be connected with a coupling sleeve.

　　(3) Pre-tighten the rod body forcefully to ensure that the top of the anchor head is close to the bottom of the hole and turn the anchor rod body to the left until it is tightened, and then install the stop plug, backing plate and nut.

　　(4) Connect conventional tension tools (such as torque wrenches, anchor rod tension meters), and implement pre-stress tensioning to the specified value.

　　(5) Grouting. Push the grouting machine into the site, connect the grouting pipe and power supply; stir the grout according to the design mix ratio, and pour it into the grouting machine; start the grouting machine, and pour the grout into the anchor hole until the end of the anchor rod The slurry flows out and the grouting pressure reaches the design value; remove the grouting joint and clean the equipment.

　　The purpose of grouting is to make the grout wrap the shell-type bolt body, effectively prevent the bolt body from corrosion and cause the bolt failure: at the same time, the grout fills the cracks and improves the surrounding rock. Therefore, the quality of grouting must be paid attention to to ensure that the grouting is full, and the supporting special grouting machine and grouting joint should be used to ensure the effectiveness of the entire prestressed anchor system. Considering that the purpose of prestressed bolt grouting is mainly to prevent corrosion of the rod body, fill cracks, and improve surrounding rock, it is recommended to use pure cement slurry with good permeability for grouting.