Safety technical measures for anchor mesh shotcret

Safety technical measures for anchor shotcreting construction of auxiliary shaft parking lot

overview: the loosening and separation of the roof of the roadway of the new turnover cage at the bottom of the auxiliary shaft can no longer meet the needs of safety production. According to the "five excellent" mine construction and underground pedestrian transportation safety of our mine, it is now decided to expand and repair this section by team 25. In order to ensure construction safety, the construction measures are specially prepared

I. location and scope of expansion:

New turnover cage exit roadway

II. Roadway section and support form:

1. After the expansion of the roadway of the new turnover cage, it is still semi-circular arch, and the net arch radius is 2450mm. After the expansion, the net height above the roadway surface of the new turnover cage is 4.15M, the net width of the new turnover cage roadway is 4.9 m (the outer edge of the track on the ditch side is 1.2m away from the upper side, and the outer edge of the track on the other side is 1.1m away from the upper side), the straight wall is 1.7 m, and the roadway floor does not move

and the cost is mainly material cost and batch forming processing cost

2. The expansion adopts "two spraying and one non-ferrous metal is a big family anchor", that is, after expanding the side and brushing the top, the temporary support and leveling are carried out in time, then the anchor bolt is laid, hung, and finally re sprayed. The top adopts ￠ 22*2250mm straight head anchor rod, the two sides adopt ￠ 20*2000mm fried dough twist anchor rod, and the diamond metal back top back side

III. construction technology and technical requirements:

1. After expanding the side and brushing the top, first strictly knock the side and ask the top, brush to the solid top and bottom, and immediately spray mortar for the first time for temporary support and leveling of the top and side, then hang the bolt, and finally spray again

2. The proportion of shotcrete materials is: Ash: sand =1:2.5, the mixing amount of accelerator is 3-4% of cement, and the water cement ratio is 0.45

3. When spraying, the nozzle should be vertical to the sprayed surface, and the distance between the nozzle and the sprayed surface should not be more than 1.5 meters. The nozzle moves slowly in a spiral way in a circular or oval track. Strictly control the water cement ratio, wind pressure and the dosage of accelerator to minimize rebound. The thickness of the spray layer shall not be less than 100mm, and the formation shall be beautiful, the spray layer shall be dense, the surface shall be flat, and there shall be no barefoot and skirt wearing

4. The bolt specification is ￠ 20*2000mm fried dough twist bolt (two sides) and ￠ with simple shape and structure, fair 22*2250mm straight head bolt, the spacing between rows is 600*600mm, the bolt is perpendicular to the roadway contour and rock surface, and the bottom anchor rod is 16 degrees. The length of the anchor rod exposed from the anchor plate shall be less than 50, and it can meet the leveling of the nut. Tighten the nut with a special torque wrench to make the anchor plate tightly press the rock surface. The pre tightening force distance of anchor rod shall not be less than 200n m。

5. The lap length of the metal is 100 mm, and one buckle is connected every 200 mm. It is arranged according to the "three flowers", and the tray is pressed tightly and close to the rock surface

6. The construction shall be carried out in strict accordance with the middle waist line hung by the geological survey department

develop functional packaging materials with a certain technical content. IV. safety measures:

I) blasting operation:

1. In front of the eyes, we must clean up the live gangue and dangerous rocks on the roof of the roadway and the sundries in the roadway within 10 meters before and after the expansion point

2. Before and after the blasting operation in each shift, and before the workers enter the construction site, the shift leader and the shift leader should strictly check the roof, live slag and whether there are exposed old anchor bolts from the outside to the inside, and the protection of cable pipelines, and strictly implement the roof knocking system and specially assigned person supervision system. The team leader personally arranges two experienced old workers to carry out the matching work. One person uses a long handle tool to knock on the side and ask the top to deal with the live gangue, and the other person monitors the top plate full-time. If any hidden danger is found, it can be handled in time, and it can be carried out only after there is no hidden danger. Operators must stand in a safe place under permanent support to operate, and ensure that the exit road is unblocked. Overhead operation is strictly prohibited

3. Small guns are mainly used for blasting, and the depth of blast holes is not less than 0.6 meters. The number of blast holes in each round of blasting shall not exceed 5, and the charge of each hole shall not exceed 1 knot. It is emphasized that more holes should be drilled and less charge. The remaining blast holes must be sealed and filled with gun mud, and open blasting is strictly prohibited

4. Before shooting, the shift leader must assign a special person to remove the cables within 20 meters in front and behind the two sides of the roadway and cover them with old belts, 50 cm thick pine planks, etc. for proper protection, and effectively cover the pipelines with thick planks, old belts, etc. after the power failure of the open line at the construction point, the old belts can be used to wrap them tightly and wrap them with colored striped cloth

5. Shooting must adhere to the "one shot three inspection system". Before shooting, the team leader must personally assign special personnel to guard on the warning line 150 meters away from all passageways and all roads that may enter the shooting site. The guard must guard at a covered and safe place. The team leader must count the number of people and issue the shooting order only after confirmation., After receiving the blasting order from the team leader, the shooter shall wait at least 5 seconds before blasting