RU2020117180A - METHOD FOR PROVIDING SUPPORT DUE TO SYNERGIC VOLTAGE OF DEFORMATION OF ANCHOR BOLT AND ANCHORING ROPE - Google Patents

Claims (27)

1. A method of providing support due to synergistic deformation stress of an anchor bolt and an anchoring rope, including: stage A, at which the area of damage to the surrounding rocks of the mine working is determined and the support load required for these rocks is calculated, while the area of damage to the surrounding rocks is obtained by theoretical calculations or in-site measurements, and the support load - by theoretical calculations; stage B, which evaluates the subsidence of the roof of the mine, including calculating the maximum bend based on the beam bending formula; Stage C, in which a preliminary check of the characteristics of the materials of the anchor bolt and the anchoring rope is carried out, taking into account the state of the materials of the adjacent mine workings, and this check includes the application of pulling and breaking loads; step D, in which the lengths of the anchor bolt and the anchor rope are determined, including: Sub-step D1, in which the lengths of the free sections of the anchor bolt and the anchor rope are determined, and Sub-step D2, in which the lengths of the anchor bolt and the anchor rope themselves are determined; step E, where the strength of the anchor bolt is corrected, and step C is repeated if the strength requirements are not satisfied; and the strength correction includes stresses on the anchor bolt and anchoring rope under conditions of maximum subsidence of the roof of the mine; step F, which determines the installation intervals of the anchor bolts and anchor ropes, including: substage F1, in which the installation interval of the anchor bolts is pre-determined and the support load of the anchor bolt is calculated; Sub-step F2, which calculates the support load required for the securing rope and determines the installation interval of the securing ropes; as well as substage F3, which checks the rationality of the intervals for the installation of anchor bolts and anchoring ropes; and stage G, in which the design drawing of the supports is drawn up, the anchor bolt and the anchoring rope are installed in the roof, the stresses acting on them are measured, and the load on the roof slab is monitored. 2. The method according to claim 1, characterized in that the area of damage to the surrounding rocks of the mine workings at stage A is calculated based on the hypothesis of the collapse roof or the hypothesis of an elastically plastic medium and is measured by the method of downhole television detection, and the reference load P ₀ is determined by the formula: Р ₀ = kγbD, where k is the strength factor; γ - unit of weight of roof rocks, N / m ³ ; b is the size of the plastic deformation zone, m; D is the width of the mine, m. 3. The method according to claim 1, characterized in that the bending formula of the beam at stage B is expressed in the following form:

where: γ is the weight per unit volume of the roof rock; E - modulus of elasticity of the roofing rock; L - width and m ₀ - the thickness of the mine working actually measured; ω - subsidence of the roof of the mine, i.e., the maximum bend. 4. A method according to claim 1, characterized in that the characteristics of the anchor bolt and the anchor rope in step C are tensile tested in the room, and the relationship between the extension and stress on the anchor bolt and the anchor rope is plotted by means of a tension test in the room. 5. The method according to claim 1, characterized in that the lengths of the free sections at the substage D1 of stage D are calculated on the basis of the principle of synergistic deformation of the anchor bolt and the securing rope, the maximum elongation δ _{1 of the} free section of the anchor bolt is equal to the maximum elongation δ _{2 of the} free section of the securing rope, and the lengths of the free sections of the anchor bolt and the securing rope are determined in accordance with the formula for the length of the free section, the subsidence of the roof of the mine working and the maximum extension: δ ₁ = L ₁ × ε ₁ = δ ₂ = L ₂ × ε ₂ = ω, as well as at substage D2, the lengths of the anchor bolt and the special anchor rope are calculated as follows: to calculate the length L _{b of the} anchor bolt, first determine the length L _{b0 of} the anchor bolt securing section and the length L _{b1 of the} open section of the anchor bolt, then the length of the anchor bolt is determined by the formula: L _b = L ₁ + L _b0 + L _b1 ; to calculate the length L _{c of the} fastening rope, first determine the length L _{c0 of} its fastening section and the length L _{c1 of} its open section, and then calculate the length of the fastening rope using the following formula: L _c = L ₂ + L _c0 + L _c1 . 6. The method according to claim 5, characterized in that the length of the anchor bolt securing section is from 0.3 to 0.5 m, and the length of the open section of the anchor bolt is from 0.1 to 0.3 m; the length of the fastening section of the fastening rope is from 1 to 1.5 m, and the length of its open section is from 0.2 to 0.3 m. 7. The method according to claim 1, characterized in that the correction of the strength of the anchor bolt and the anchor rope at stage E includes taking into account the size ratio when comparing the stress on the anchor bolt F ₁ under conditions of maximum subsidence of the roof of the mine and the breaking load on the anchor bolt [F ₁ ], and the ratio of dimensions when comparing the stress _{on the anchor rope F 2} under the condition of the maximum subsidence of the roof of the mine and the breaking load on the anchor bolt [F ₂ ]. 8. The method according to claim. 2, characterized in that in step F, preliminary determination of the installation interval in substage F1 includes determining the number n _{b of} anchor bolts within a unit length in the direction of the mine, calculating the support load P _{b of the} anchor bolt in accordance with voltage F ₁ on it, subject to the maximum subsidence of the roof of the mine and the actual working coefficient η _{b of the} anchor bolt, which is expressed in the following form: P _b = η _b n _b F ₁ ; the supporting load P _{from the} securing rope at the substage F2 is calculated on the basis of the following formula: P _c = P ₀ -P _b ; the number n _{c of} anchoring ropes within a unit of length in the direction of the mine working is calculated by the actual operating coefficient η _{from the} anchor rope and the stress F ₂ on it, subject to the maximum subsidence of the roof of the mine, which is expressed in the following form:

the installation interval of the fixing ropes is determined by the number n _{c of the} anchor bolts within the unit of length in the direction of the mine working; and if the number n _{c of} anchor bolts per unit length in the mine direction is greater than the number n _{b of} anchor bolts per unit length in the mine direction in substage F3, substage F1 is repeated.