Safety technical measures for bolt support constru

Safety technical measures for anchor bolt support construction of 601 transportation roadway

at present, 601 transportation roadway was originally designed for permanent support of miners' steel, and the temporary support adopts front detection beam support. According to the lithology of the head-on roof and the structure of coal and rock strata, the permanent support of 601 haulage roadway is changed to anchor support after mining research. In order to ensure construction safety, the following supplementary safety measures are specially formulated

I. preparation before construction:

1. The construction team prepares anchor bolts, resin medicine rolls, supporting plates, nuts, metals (the metals are processed with 12 # yuan wires), temporary support materials, etc. as planned

II. Construction sequence:

(1) knock on the top → temporary support → anchor hole → anchorage

(2) proceed from north to South with the heading direction

IV. measures to stabilize the product performance of bolt support technology:

1. Bolt support

① bolt and components: the bolt is made of ￠ 18 deformed steel, and the tail thread section of the bolt is 0.05m long; Specification of metal arc square bracket: long × wide × Thickness =120 ㎜ × 120㎜ × 8㎜； One M16 ㎜ nut on each anchor rod

② bolt support parameters:

bolt length: 2m/piece. Specification of resin roll: length 350 mm, diameter ￠ 23 mm

anchoring form: end anchoring, 3 rolls of resin anchoring agent are used for each anchor bolt

anchoring force: 60kn

anchor rod arrangement: square arrangement. The bolt is perpendicular to the roadway contour, and the bolt does not affect the accuracy of the spring testing machine, so it must be arranged in the rock seam

spacing between anchor rods and rows: 0.7m, locally smaller than the broken section, and the spacing between anchor rods and rows is 0.6m

specification of each metal: long × Width =2.0m × 1.0m, metal hole specification: 100 mm × 100㎜。

2. Checking calculation of bolt support parameters

①. Bolt length

l ≥ a+b+h=0.4+0.1+1.5=1.4 (m)

where l - bolt length

a - depth of anchor bolt anchored into solid and stable suspended rock stratum (generally 0.25 ~ 0.4m, take 0.4m)

B - then cast by injection molding - exposed length of anchor rod. With supporting plate ≯ 0.1M

H - the thickness of the suspended rock stratum (the layered thickness is 1.2m, and the broken section is 1.5m)

the effective length of anchor rod is 2.0m, which meets the requirements

②. Bolt diameter

where D - bolt diameter, mm

q - Design anchoring force, 60kn

rt - yield strength of deformed steel bar, 335kn

select deformed steel bar with d=18mm to make anchor rod

③ bolt spacing: the weight of rock borne by each bolt is less than or equal to the bolt anchoring force, which is less than the rod breaking force. According to the data, the yield strength of deformed steel bar with a diameter of ￠ 18mm is 335mpa, and the bearing capacity of the rod body is 85kn

where Q - Design anchoring force, 60kn

k - safety factor (take 2)

h - Anchorage thickness (h=1.0m)

r -- unit weight (r=24.5kn/m ⊃;)

the designed maximum spacing is 0.7m, which is less than the theoretical value of 0.845m, meeting the requirements

the above bolt spacing design also conforms to the empirical formula D ≤ 0.5l=0.5 × 2.0 = anchor parameters determined by 1.0m (D - anchor spacing, m; L - anchor length, m)