Support housing

Abstract

The subject of the invention relates to a mining support, which includes two supports (1, 2) located opposite each other and an arch segment (3) arranged between them to form a portal. Both the supports (1, 2) and the arch segment (3) are formed from profiles having a U-shaped in cross-section with a horizontal neutral axis (9) and a vertical axis of symmetry (8) dividing the profile into a first arm (A) and an opposite symmetrical second arm (B). The first and second arms (A, B) of the support (1, 2) profiles and the arch segment (3) facing outwards of the portal, and the position of the first and second arms (A, B) of the support (1, 2) profiles corresponds to the position of the first and second arms (A, B) of the arch segment (3) profile. The arch segment (3) overlaps each of the supports (1, 2) with a lap and is connected to the support (1, 2) in the lap area by means of at least a movable clamp (5a) located at the end of the support (1, 2), and a stationary clamp (5b) located at the end of the arch segment (3), each stationary clamp (5b) has an fixing opening (22). Anchor openings (10) are formed in the supports (1, 2) and in the segment (3), wherein at least two anchor openings (10) are formed in each support (1, 2) and at least one anchor opening (10) is formed in the arch segment (3). Each anchor opening (10) is located at the intersection of the neutral axis (9) and the first or second arm (A, B) of the profile, while the longitudinal axis of the anchor opening (10) extends toward the area between the end of the first and second arm (A, B) of the profile.

Description

[0001] The subject of the invention is an yielding arch type support for use in underground mine excavations.

[0002] The direct connection of a frame support with rock anchors is known from publication UA85376C2. The frame support consists of two supports and one arch segment. The channel bar segments are connected by means of clamps having outer and inner yokes, which are bolted together. The outer yoke has a circular opening at the end of the support. A rock bolt is installed through this opening and tightened with a rock bolt nut.

[0003] Publication PL240278B1 describes a support having a frame support consisting of two supports and two arch segments having U-shaped profile. The segments overlap each other and they are connected by clamps having outer and inner yokes that are bolted together. Each segment has a vertical axis of symmetry and a horizontal neutral axis, as well as a circular opening, the axis of the opening coincides with the vertical axis of symmetry. The anchor is inserted into this opening in such a way that the longitudinal axis of the anchor coincides with the vertical axis of symmetry. Rock bolts are tightened with rock bolt nuts. The yoke of the support is put on the nut of the rock anchor and attached by means of two hooks and nuts to the U-shaped profile. The supports are installed in the underground excavations or gates, while the vault segments are placed on the supports overlapping each other with an overlap. The vault segments are also arranged to overlap one another. All overlaps are fastened with clamps / locks. Further openings are drilled into the rock through round openings in a U-shaped profile. The anchors are then passed through the round openings and tightened by means of nuts. The inner yoke is then placed over the nut of the rock anchor and fastened by means of two hooks and yoke nuts to the U-shaped profile.

[0004] The pressure of the rock mass causes the surrounding rocks to move into the gates. The cross-section of the excavation decreases causing the frame support to flex and resist against the ground pressure. Internal yokes prevent longitudinal twisting of the channel profile facilitating the process of making the frame support flexible.

[0005] The internal yokes, which are put on the nuts of the rock bolts cause increase in material inputs, time and labor inputs in installation of this clamp. In addition, round openings in the frame bearing profile weaken this profile and reduce the strength of the vault segments. The maximum tensile stress acts on the round openings when the ground pressure deforms the frame support.

[0006] The purpose of the invention is to increase the strength of U-shaped profile and reduce material inputs.

[0007] A support according to the invention comprises two supports which are positioned opposite each other and an arch segment positioned between them to form a portal, both the supports and the arch segment are formed from profiles having U-shape in cross-section with a horizontal neutral axis and a vertical axis of symmetry. The vertical axis of symmetry divides the profile into a first arm and opposite second arm which is symmetrical to the first arm, wherein the first and the second arms of the support profiles and the arch segment are directed outwards from the portal, and wherein the position of the first and second arms of the support profiles corresponds to the position of the first and second arms of the arch segment profile. Whereby the arch segment overlaps each of the supports with a lap and it is connected to the support in the area of the overlap by means of at least a movable clamp located at the end of the support and a by stationary clamp located at the end of the arch segment. Each stationary clamp has a fixing opening, and anchor openings are formed in the supports and in the segment, being characteristic in that, at least two anchor openings are formed in each support and further at least one anchor opening is formed in the arch segment, wherein each anchor opening is located at the intersection of the neutral axis and the first or second arm of the profile, while the longitudinal axis of the anchor opening extends toward the area between the ends of the first arm and the second arm of the profile.

[0008] Preferably, the longitudinal axis of the opening is inclined with respect to the neutral axis of the profile at an angle of from 65° to 80°.

[0009] Preferably, in each of the supports: one anchor opening is formed in the first arm of the profile, close to the lower end of the support and a second anchor opening is formed in the second arm of the profile at a distance from the end of the arch segment, which distance is not less than half the length of the arch segment.

[0010] Preferably, the arch segment has an anchor opening formed in the second arm of the profile at the center of the arch segment.

[0011] Preferably, each of the movable clamp and the stationary clamp have an outer yoke and an inner yoke that are bolted together by means of bolt and nut assemblies, the outer yoke of each of the stationary clamps additionally has an extension in which a fixing opening is provided.

[0012] The advantage of the solution according to the invention is in that, the support housing maintains an integrity and a strength of the U-shaped profile, since the circular openings are located on the horizontal neutral axis of the U-shaped profile, where the normal deformations are close to zero.

[0013] Furthermore, no additional operations or materials are required during excavation and assembly of the composite frame-anchor support.

[0014] Adjacent openings for the rock anchors are located on different sides of the support profile to prevent longitudinal twisting of the profile and to provide reliable protection against clamp locking and blocking.

[0015] The frame support realizes its performance completely as the supports move the arch segment until the ends of the supports come into contact.

[0016] The subject of the invention is schematically illustrated in an embodiment in the drawing, in which: Fig. 1 shows the support immediately after its installation, Fig. 2 is a side view of the support when looking from S direction in Fig. 1, Fig. 3 is a view of the support in the state after strong action of ground pressure, in which its elements have been deformed, Fig. 4 is a cross-sectional view of a section of the support and the stationary clamp, Fig. 5 is a cross-sectional view of a section of a support and a movable clamp, Fig. 6 is a view of the connection of the rock anchor and the U-shaped segment, and Fig. 7 shows the stress distribution system in the support segment according to the invention.

[0017] The support shown in Fig. 1, consists of two supports 1 and 2 located one opposite to each other and an arch segment 3 connecting these supports at the top to create a portal shape.

[0018] Both the supports 1, 2 and the arch segment 3 are formed from a profile having a U-shaped cross-section with a vertical axis 8 of symmetry which axis divides the profile into a first arm A and a second arm B that is symmetrical to the first arm and opposite to it, and a horizontal neutral axis 9. The first and second arms A, B of the profile facing outwards from the portal.

[0019] The arch segment 3 overlaps the supports 1, 2 with a lap wherein the profile of the arch segment 3 is arranged inside the profile of the supports 1, 2 and the first and second arms A, B of the profile of the arch segment 3 coincide with the corresponding first and second arms A, B of the profiles of the supports 1, 2. As shown in Figs. 2, 4 and 5, in the area of the lap the arch segment 3 is connected to the supports 1, 2 by means of a movable clamp 5a and a stationary clamp 5b. Each of the movable clamp and stationary clamp has an outer yoke 6 and an inner yoke 7 that are bolted together by means of bolt and nut assemblies 24, while compressing the profiles of the arch segment 3 and each of the supports 1, 2 between them, respectively. The movable clamp 5a is located close to the end of the support 1, 2, while the stationary clamp 5b is located close to the end of the arch segment 3. The outer yoke 6 of each of the stationary clamps 5b additionally has an extension 23 in which a fixing opening 22 is provided for fixing the outer yoke 6 to the excavation wall by means of anchors. Additional clamps 5a (not shown) can be positioned between the clamps 5a, 5b.

[0020] As shown in Figs. 6 and 7 circular anchor openings 10 for the anchors are formed in the profiles of the arch segment 3 and of the supports 1, 2 each opening 10 is arranged at the intersection of the neutral axis 9 and the first or the second arm A, B of the profile. The longitudinal axis of each opening 10 extends in the direction towards the area between the ends of the first arm A and the second arm B of the profile and it is inclined at an angle α of 70° with respect to the neutral axis 9. The value of the angle α can range from 65° to 80° in order to ensure optimal strength conditions of the profile.

[0021] In the shown embodiment, each of the supports 1, 2 has two openings 10 first and second respectively, wherein the first opening 10 is formed in the first arm A of the profile of each of the supports 1, 2, close to the lower end of the support 1, 2, and the second opening 10 is formed in the second arm B of each of the supports 1, 2 in the middle area of the supports 1, 2 at a distance from the end of the arch segment 3, which distance is not less than half the length of the arch segment 3. On the other hand, the opening 10 in the arch segment 3 is located in the center thereof, in the second arm B of the profile of the arch segment 3. It should be noted that the number of openings 10 shown in the embodiment example is the smallest number that is necessary for the proper operation of the support housing according to the invention, while providing additional openings 10 is possible both in the supports 1, 2, as well as in the arch segment 3 to ensure reinforcement of the structure during installation in situ.

[0022] Installation of the support in the excavation consists in installing supports 1, 2 in the tunnel on the rock floor 19 that is secured by the lagging 13 immediately after excavation of the underground gate (excavation), after intensive uplifting 20 and after ripping of the floor 21. The arch segment 3 is placed on the supports 1, 2 so that it overlaps them with a suitable lap and at the site of the lap it is fixed relative to the supports 1, 2 by means of movable and stationary clamps 5a, 5b. Through circular openings 10 in the profiles of the supports 1, 2 and the arch segment 3 and through fixing openings 22 in the outer yokes 6 of stationary clamps 5b, along the longitudinal axes of circular openings 10 and fixing openings 22, openings 15 are drilled in the rock 14. Anchors 11, 16, 17, 18 are placed in the openings 15 which anchors are tightened with nuts 12. In the case of openings 10, shaped washers 25 are additionally used on the anchors 11, 17, 18 to allow proper orientation of the respective anchor with respect to the axis of corresponding opening 10.

[0023] Adjacent rock anchors are mounted on different sides of the housing profile to prevent longitudinal twisting of the housing profiles and to provide reliable protection against clamp (lock) locking.

[0024] Fig. 3 shows the condition of the support according to the invention, after strong action of ground pressure. The pressure of the rock mass damages the surrounding rock 14 and deforms the support housing. The frame support offers resistance only in the plasticization regime, and the stationary clamps 5b cannot block (lock) themselves, because the rock anchors prevent its longitudinal twisting. Eventually, supports 1, 2 yield to their maximum and their ends contact one to each other, while the end of the arch segment 3 stops directly at the anchor 11. The exemplary initial section of the underground gallery or excavation has a surface area of 20 m 2< , while the cross-section of the gallery reduces to 4.8 m 2< . After ripping the floor of the gallery up to 13.6 m 2< is recovered. The convergence of the surrounding cracked rocks disappears because an extensive relaxation zone appears around the gallery.

Claims

1. A mining support comprising two supports (1, 2) which are positioned opposite to each other and an arch segment (3) positioned between them to form a portal, wherein both the supports (1, 2) and the arch segment (3) are formed from profiles having U-shaped in cross-section with a horizontal neutral axis (9) and a vertical axis (8) of symmetry, which axis (8) of symmetry divides the profile into a first arm (A) and opposite second arm (B) symmetrical to the first arm, wherein the first and the second arms (A, B) of the support (1, 2) profiles and the arch segment (3) are facing outwards away from the portal, and wherein the position of the first and the second arms (A, B) of the support (1, 2) profiles corresponds to the position of the first and second arms (A, B) of the arch segment (3) profile, the arch segment (3) overlaps each of the supports (1, 2) with a lap and in the area of the lap it is connected to the support (1, 2) by means of at least a movable clamp (5a) located close to the end of the support (1, 2) and by means of a stationary clamp (5b) located at the end of the arch segment (3), wherein each stationary clamp (5b) has a fixing opening (22), and anchor openings (10) are formed in the supports (1, 2) and in the segment (3), characterized in that at least two anchor openings (10) are provided in each support (1, 2), and at least one anchor opening (10) is formed in the arch segment (3), and wherein each anchor opening (10) is located at the intersection of the neutral axis (9) and the first or second arm (A, B) of the profile, while the longitudinal axis of the anchor opening (10) extends towards the area between the end of the first arm and the second arm (A, B) of the profile.

2. The mining support according to claim 2, characterized in that the longitudinal axis of the opening (10) is inclined with respect to the neutral axis (9) of the profile at an angle (α) of from 65° to 80°.

3. The mining support according to claim 1 or 2, characterized in that in each of the supports (1, 2) one anchor opening (10) is formed in the first arm (A) of the profile, close to the lower end of the support (1, 2), and the second anchor opening (10) is formed in the second arm (B) of the profile, opposite to the first arm of the profile and at a distance from the end of the arch segment (3) which distance is not less than half the length of the half-arched segment (3).

4. The mining support according to claim 1 or 2, characterized in that the arched segment (3) has an anchor opening (10) formed in the second arm (B) of the profile, at the center of the arched segment (3).

5. The mining support according to claim 1, characterized in that each of movable clamp (5a) and stationary clamp (5b) have an outer yoke (6) and an inner yoke (7) that are bolted together by means of bolt and nut assemblies (24), wherein the outer yoke (6) of each stationary clamp (5b) has additionally an extension (23) in which a fixing opening (22) is provided.

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