Primary pillar stepped reinforcing structure and pillar reinforcing method

Abstract

The invention provides a primary ore pillar stepped reinforcing structure. The primary ore pillar stepped reinforcing structure comprises a reinforcing body, a flexible buffer layer and an anchoring component. The reinforcing body has a trapezoidal outline and is divided into a plurality of stress areas so as to adapt to gradient stress distribution of the ore pillar; the flexible buffer layer is arranged between the reinforcing body and the original ore pillar; and the anchoring component penetrates through the reinforcing body and the original ore pillar and is used for providing active constraining force. The reinforcing structure is trapezoidal, and compared with a traditional section structure, the contact area of the upper end and the lower end is enlarged; meanwhile, overlying strata concentrated loads can be dispersed, stress is evenly transmitted to ore pillars and surrounding rocks, the risk of inclined shear stress concentration is remarkably reduced, and the overall anti-sliding and anti-overturning stability is enhanced; the pre-stressed anchor rod provides active constraint and inhibits deformation development of the ore pillar; and the wedged bottom is embedded into a bottom plate groove, so that the horizontal constraining force is improved, the instability of an ore pillar-reinforcing system is avoided, and the service life is prolonged.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of ore pillar reinforcement, and particularly relates to a primary ore pillar ladder type reinforcement structure and an ore pillar reinforcement method. BACKGROUND

[0002] In underground mining operations, the primary ore pillar is a key component for bearing the load of overlying rock and maintaining the stability of the mining structure. Its mechanical response and failure mode directly affect mining safety and efficiency. The instability of the ore pillar is always a key bottleneck restricting safe and efficient mining.

[0003] Traditional ore pillar reinforcement techniques mainly rely on two types of means:

[0004] Equal-section grouting reinforcement uses equal-section concrete pouring bodies or sprayed concrete to wrap the ore pillar, thereby increasing the overall stiffness by increasing the cross-sectional size;

[0005] Single anchor rod support provides radial constraint by arranging anchor rod groups to inhibit the expansion of rock fissures.

[0006] Such techniques effectively reduce the risk of brittle failure in shallow mining by enhancing the strength of the ore pillar itself or applying external constraints, thereby providing a basic guarantee for the safe advancement of mining. However, as the mining depth increases and the mining stress becomes more complex, the traditional reinforcement methods have the following defects:

[0007] 1. The equal-section reinforcement body cannot adapt to the internal gradient stress distribution of the ore pillar, with stress concentration at the column foot and shear stress peak at the column body, leading to premature crushing in some areas;

[0008] 2. The interface slip effect between the rigid reinforcement body and the ore pillar rock mass due to the difference in elastic modulus aggravates the diagonal shear failure;

[0009] 3. High-altitude pouring from top to bottom requires the erection of a complex support system, which not only increases the risk of roof exposure but also causes the interface bond strength to decay due to disturbance during the curing period. SUMMARY

[0010] The purpose of the present application is to provide a primary ore pillar ladder type reinforcement structure and an ore pillar reinforcement method that solve the problem of gradient stress distribution without the need for a complex support system.

[0011] The primary ore pillar ladder type reinforcement structure provided by the present application includes a reinforcement body, a flexible buffer layer, and an anchoring member. The reinforcement body has a trapezoidal profile and is divided into multiple stress regions to adapt to the gradient stress distribution of the ore pillar. The flexible buffer layer is arranged between the reinforcement body and the primary ore pillar. The anchoring member penetrates the reinforcement body and the primary ore pillar to provide active restraint force.

[0012] In an embodiment of the above structure, the plurality of stress regions comprises a stable zone, a transition zone and a strong disturbance zone arranged from top to bottom, wherein the strong disturbance zone is located at the bottom of the pillar and bears the highest stress.

[0013] In an embodiment of the above structure, the flexible buffer layer is a rubber-asphalt composite layer with a thickness of 2-5 cm and is laid on the surface of the original pillar.

[0014] In an embodiment of the above structure, the anchoring member is a pre-stressed anchor rod, one end of which is anchored in the original pillar with an anchoring depth of not less than 1 m, and the other end is embedded in the interior of the reinforced body.

[0015] In an embodiment of the above structure, the original pillar is located on the floor surrounding rock, and the floor surrounding rock is provided with a floor groove, the bottom end of the reinforced body is embedded in the floor groove, and the groove depth is 3-5 cm to provide horizontal constraint.

[0016] In an embodiment of the above structure, the reinforced body comprises a pouring mold and a concrete pouring body, the pouring mold is provided with a steel reinforcement cage, a pouring reserved hole and a detachable partition plate, and the partition plate is used to isolate the plurality of stress regions.

[0017] A method for reinforcing a ladder-shaped original pillar, comprising the following steps:

[0018] S1, construction preparation and mold installation: design a ladder-shaped pouring mold according to the size of the pillar, and embed the bottom end of the mold into the groove of the floor surrounding rock;

[0019] S2, reinforcement of the strong disturbance zone: lay a flexible buffer layer in the bottom layer area of the original pillar, set and anchor the anchoring member on the original pillar, and cure the poured concrete;

[0020] S3, reinforcement of the transition zone: remove the partition plate, lay a flexible buffer layer in the middle area of the original pillar, set the anchoring member, and cure the poured concrete;

[0021] S4, reinforcement of the stable zone: remove the partition plate, lay a flexible buffer layer in the top area, set the anchoring member, and cure the high-pressure grouting concrete through the reserved hole.

[0022] In steps S2, S3 and S4, the concrete comprises ordinary concrete and high-strength concrete; wherein high-strength concrete is used in the strong disturbance zone, and ordinary concrete is used in the stable zone and the transition zone.

[0023] In steps S2, S3 and S4, setting the anchoring member comprises vertically drilling anchor rod holes on the side wall of the original pillar, with a hole diameter of 42-50 mm and a spacing of 80-120 cm.

[0024] The curing time in step S2 is not less than 14 days, and the curing time in steps S3 and S4 is not less than 7 days; and the filling compactness is ensured by controlling the grouting flow through a high-pressure grouting pump in step S4.

[0025] The beneficial effects of the present application are as follows:

[0026] 1. The reinforcing structure is trapezoidal, which expands the upper and lower contact areas compared with the traditional cross-sectional structure; at the same time, it can disperse the concentrated load of the overlying strata, so that the stress is uniformly transmitted to the ore pillar and surrounding rock, significantly reducing the risk of oblique shear stress concentration, and enhancing the overall anti-sliding and anti-overturning stability; the pre-stressed anchor provides active restraint to inhibit the development of ore pillar deformation; the wedge-shaped bottom is embedded into the bottom plate groove to improve the horizontal restraint force and avoid the instability of the ore pillar-reinforcement system, thereby prolonging the service life;

[0027] 2. According to the stress distribution difference of the ore pillar, differential material combination is adopted to achieve partition adaptation by accurately matching the material strength and regional stress level; the stress distribution of the ore pillar can be optimized to improve the bearing capacity; the material cost is reduced, and the ineffective investment of high-priced materials is reduced; the flexible composite cushion material strengthens the interface bonding to form a collaborative stress system of ore pillar-pouring body-surrounding rock, and inhibits stress concentration caused by slight deformation;

[0028] 3. The reinforcing method adopts a phased construction process from bottom to top, combined with detachable partition plates and pouring molds; through the positive installation method, high-altitude work is simplified, personnel can easily go up and down, the difficulty of on-site construction is reduced, and safety is improved; the curing period is controlled in stages to ensure quality; the reserved hole design facilitates high-pressure grouting filling, improves the compactness, and is more convenient for daily maintenance. BRIEF DESCRIPTION OF DRAWINGS

[0029] Figure 1 The cross-sectional view of the ore pillar and the reinforcing structure of an embodiment of the present application.

[0030] Figure 2 The cross-sectional view of the ore pillar and the reinforcing structure of an embodiment of the present application. Figure 1 The cross-sectional view of the ore pillar and the reinforcing structure of an embodiment of the present application.

[0031] Figure 3 The cross-sectional view of the ore pillar and the reinforcing structure of an embodiment of the present application. Figure 1 The cross-sectional view of the ore pillar and the reinforcing structure of an embodiment of the present application.

[0032] The reference signs are as follows:

[0033] 1. Pouring mold; 11, steel bar; 12, pouring reserved hole; 13, partition plate; 2, concrete pouring body; 3, flexible cushion material; 4, pre-stressed anchor; 5, original ore pillar; 6, bottom plate groove; A, stable zone, B, transition zone, C, strong disturbance zone. DETAILED DESCRIPTION

[0034] The related technical solutions will be described clearly and completely below in combination with the drawings in the embodiments of the present application. The described embodiments are only some of the embodiments, but not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the scope of the present application.

[0035] In combination with Figure 1 , Figure 2 and Figure 3 It can be seen that the original pillar ladder type reinforcing structure disclosed in the embodiment comprises a pouring mold 1, a concrete pouring body 2, a flexible buffer material 3 and a pre-stressed anchor rod 4.

[0036] The top end of the original pillar 5 supports the roof surrounding rock, and the bottom end stands on the floor surrounding rock.

[0037] The pouring mold 1 is a trapezoidal peripheral support frame, which is divided into three layers from top to bottom, corresponding to the stable area A, the transition area B and the strong disturbance area C.

[0038] The bottom end of the pouring mold 1 is embedded into the pre-set floor groove 6 of the floor surrounding rock, the groove depth is 3-5 cm, which provides horizontal constraint, enhances the anti-sliding and anti-overturning stability.

[0039] The pouring mold 1 is internally provided with steel bars 11, the steel bars are fixed by welding to form a framework, the steel bar junctions and the connection positions of the steel bars and the anchor rods form welding points, which ensure the integrity of the structure.

[0040] The pouring mold 1 is provided with pouring reserved holes 12 on the side surface, the hole diameter is not less than the outer diameter of the grouting pipe, which facilitates the high-pressure grouting in the last stage. The pouring mold is provided with a partition plate 13 for temporarily isolating each area, which facilitates the construction in stages.

[0041] The overall size of the pouring mold 1 is designed according to the size of the original pillar 5 and the overlying load, which ensures that the pouring mold 1 is closely combined with the roof surrounding rock and the floor surrounding rock.

[0042] The concrete pouring body 2 is formed by pouring through the pouring mold 1, which is also divided into three layers from top to bottom, i.e., the stable area A, the transition area B and the strong disturbance area C. The stress in the stable area A is relatively low, the stress in the transition area B is moderate, and the stress in the strong disturbance area C is the highest. The concrete pouring body is injected through the pouring reserved holes 12 to ensure the dense filling.

[0043] The stable area A and the transition area B are poured with ordinary concrete, and the cement sand ratio is 1:2; the strong disturbance area C is poured with high-strength concrete, and the cement mortar ratio is 1:1.2, and the water-binder ratio is 0.28-0.32.

[0044] The flexible buffer material 3 is a rubber-asphalt composite layer with a thickness of 2-5 cm, which is attached to the surface of the primary pillar 5. This material can adapt to the slight deformation of the surrounding rock, avoid stress concentration, and enhance the interface adhesion.

[0045] Anchor rod drill holes are vertically arranged on the side of the primary pillar 5, with a hole diameter of 42-50 mm and a spacing of 80-120 cm. One end of the pre-stressed anchor rod 4 is anchored in the primary pillar through the anchor rod drill hole, with an anchoring depth of not less than 1 meter. The other end is embedded in the transition zone B and the strongly disturbed zone C of the concrete pouring body 2, providing active restraint force.

[0046] The function of this reinforcement structure is to disperse the concentrated load of the overlying rock strata through the trapezoidal structure and zoning design, so that the stress is uniformly transmitted to the primary pillar and surrounding rock, significantly reducing the risk of inclined shear stress concentration. The enlarged end of the trapezoidal structure optimizes the axial compressive stress distribution; the zoned differential material precisely matches the regional stress level; the flexible composite buffer material absorbs slight deformation; the pre-stressed anchor rod provides active restraint; and the wedge effect of the bottom plate groove enhances the horizontal constraint. Ultimately, a pillar-pouring body-surrounding rock collaborative stress system is formed, which inhibits deformation development, improves anti-sliding, anti-overturning stability, and service life.

[0047] A method for reinforcing the primary pillar using the above-mentioned stepped reinforcement structure, the specific steps are as follows:

[0048] S1, construction preparation and mold installation:

[0049] A trapezoidal pouring mold is designed according to the size of the primary pillar and the overlying load. The mold is divided into three layers from top to bottom: stable zone A, transition zone B, and strongly disturbed zone C. A bottom plate groove with a depth of 3-5 cm is opened in the surrounding rock at the bottom of the mold, and the bottom end of the mold is embedded in the groove to enhance the horizontal constraint using the wedge effect.

[0050] S2, reinforcement construction of the strongly disturbed zone C:

[0051] A steel reinforcement framework is erected in the strongly disturbed zone C of the bottom layer of the mold, and the nodes are welded and fixed. A flexible buffer material is laid on the surface of the primary pillar corresponding to the position of the strongly disturbed zone C, with a thickness of 2-5 cm. Anchor rod drill holes are vertically arranged on the side wall of the mold corresponding to the position, with a hole diameter of 42-50 mm and a spacing of 80-120 cm. One end of the pre-stressed anchor rod is anchored in the primary pillar through the drill hole, with a depth of not less than 1 meter.

[0052] C60 high-strength concrete is used for pouring, which is poured directly from the top. The cement mortar ratio is 1:1.2, and the water-cement ratio is 0.28-0.32. The curing time is ≥14 days to ensure that the concrete strength is fully formed.

[0053] S3, reinforcement construction of the transition zone B:

[0054] Remove the partition plate between the strong disturbance area C and the transition area B; the construction personnel stand on the solidified strong disturbance area C to work, install the steel reinforcement framework of the transition area and weld; lay the flexible buffer material on the surface of the primary ore pillar corresponding to the position of the transition area B, with a thickness of 2-5 cm; vertically open the anchor rod drilling hole corresponding to the position on the side wall of the mold, with a hole diameter of 42-50 mm and a spacing of 80-120 cm; then anchor one end of the pre-stressed anchor rod in the primary ore pillar through the drilling hole, with a depth of ≥1 m;

[0055] Pour with C25 ordinary concrete, pour directly from the top, with a cement mortar ratio of 1:2; maintain for ≥7 days;

[0056] S4, reinforcement construction of the stable area A:

[0057] Remove the partition plate between the transition area B and the stable area A; lay the flexible buffer material on the surface of the primary ore pillar corresponding to the position of the transition area A, with a thickness of 2-5 cm; vertically open the anchor rod drilling hole corresponding to the position on the side wall of the mold, with a hole diameter of 42-50 mm and a spacing of 80-120 cm; then anchor one end of the pre-stressed anchor rod in the primary ore pillar through the drilling hole, with a depth of ≥1 m;

[0058] Reserve a pouring hole on the top of the mold, with a hole diameter ≥ the outer diameter of the grouting pipe; pour C25 ordinary concrete into the pouring hole through the high-pressure grouting pump; control the grouting flow to ensure filling and compaction, and maintain for ≥7 days; after maintenance, clean the impurities and floating slurry in the pouring hole, and then seal with C25 concrete.

[0059] Finally, it should be noted that: the above only for the preferred embodiments of the present application, and not for limiting the present application, although in detail with reference to the foregoing embodiments, for those skilled in the art, it still can be modified, or part of the technical features of the equivalent replacement. Any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present application, should be included in the protection scope of the present application.

Claims

1. A primary pillar ladder-type reinforcement structure, characterized by: The reinforcement body, the flexible buffer layer and the anchoring member are included. The reinforcement body has a trapezoidal profile and is divided into multiple stress regions to adapt to the gradient stress distribution of the pillar; the flexible buffer layer is arranged between the reinforcement body and the original pillar; and the anchoring member penetrates the reinforcement body and the original pillar to provide active constraint force.

2. The primary pillar ladder-type reinforcement structure according to claim 1, characterized in that: The multiple stress regions include, from top to bottom, a stable region, a transition region and a strong disturbance region, wherein the strong disturbance region is located at the bottom of the pillar and bears the highest stress.

3. The primary pillar ladder-type reinforcement structure according to claim 1, characterized in that: The flexible buffer layer is a rubber-asphalt composite layer with a thickness of 2-5 cm and is laid on the surface of the original pillar.

4. The primary pillar ladder-type reinforcement structure according to claim 1, characterized in that: The anchoring member is a pre-stressed anchor rod, one end of which is anchored in the original pillar with an anchoring depth of not less than 1 m, and the other end of which is embedded in the interior of the reinforcement body.

5. The primary pillar ladder-type reinforcement structure according to claim 1, characterized in that: The original pillar is located on the floor surrounding rock, the floor surrounding rock is provided with a floor groove, and the bottom end of the reinforcement body is embedded in the floor groove with a groove depth of 3-5 cm to provide horizontal constraint.

6. The primary pillar ladder-type reinforcement structure according to claim 1, characterized in that: The reinforcement body includes a pouring mold and a concrete pouring body; the pouring mold is provided with a steel reinforcement cage, a pouring reserved hole and a detachable partition plate, and the partition plate is used to isolate the multiple stress regions.

7. A primary pillar step method of reinforcing, characterised by, The method comprises the following steps: S1, construction preparation and mold installation: design a trapezoidal pouring mold according to the size of the pillar, and embed the bottom end of the mold into the groove of the floor surrounding rock; S2, strong disturbance region reinforcement: lay a flexible buffer layer in the bottom layer region of the original pillar, set and anchor the anchoring member on the original pillar, and cure the poured concrete; S3, transition region reinforcement: remove the partition plate, lay a flexible buffer layer in the middle region of the original pillar, set the anchoring member, and cure the poured concrete; S4, stable region reinforcement: remove the partition plate, lay a flexible buffer layer in the top region, set the anchoring member, and cure the poured concrete by high-pressure grouting.

8. The primary pillar step-stressing method as claimed in claim 7, c h a r a c t e r i z e d b y: In steps S2, S3 and S4, the concrete includes ordinary concrete and high-strength concrete; wherein high-strength concrete is used in the strong disturbance region, and ordinary concrete is used in the stable region and the transition region.

9. The primary pillar step-stressing method as claimed in claim 7, wherein: In steps S2, S3 and S4, setting the anchoring member includes vertically opening anchor rod drill holes on the side wall of the original pillar with a hole diameter of 42-50 mm and a spacing of 80-120 cm.

10. The primary pillar step-stressing method as claimed in claim 7, wherein: The curing time in step S2 is not less than 14 days, and the curing time in steps S3 and S4 is not less than 7 days; in step S4, the grouting flow is controlled by a high-pressure grouting pump to ensure filling and densification.

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