Combined support treatment method for mine tunnel roof water dripping area

Abstract

This invention discloses a combined support and treatment method for water seepage areas in mine tunnel roofs, belonging to the field of surrounding rock support technology for mine roadways. It includes surveying the roadway geology and water seepage conditions, determining the basis for support selection, and optimizing composite support materials suitable for the water seepage environment; constructing a support system with a rigid anchor mesh framework and a three-layer composite cement blanket water-proof layer; deploying PVC diversion pipes for water diversion and control; and using a double-layer cement blanket overlapping structure in severely water-seeped areas. After verifying the support parameters through numerical simulation, standardized construction is carried out, including rock clearing, cement blanket laying, diversion, anchor mesh installation, and water spraying maintenance, with continuous monitoring of the support status. Combining the water-proof and erosion-resistant advantages of the cement blanket with the rigid support of the anchor mesh, a triple synergistic support effect is achieved. This eliminates the need for on-site concrete mixing and spraying, resulting in high construction efficiency, good support stability, and low post-construction maintenance. It effectively solves the problem of support failure in water-seeped roadways and is suitable for water seepage roadway treatment operations in various metal mines.

Description

Technical Field

[0001] This invention relates to the field of mine roadway surrounding rock support technology, specifically a combined support and treatment method for water seepage areas in the mine roadway roof. Background Technology

[0002] In underground iron ore mining, water seepage from the roof is a common and difficult-to-manage engineering problem. Continuous water seepage from the roof softens and dissolves the roof rock mass, reduces the mechanical strength of the surrounding rock, and erodes conventional support structures, easily inducing roof falls, spalling, and collapses. Long-term dampness and water accumulation underground also deteriorates the working environment, causes corrosion of underground equipment, and increases the investment in later maintenance of the roadways.

[0003] Currently, the mainstream support methods for water-soaked roadways in iron mines include shotcrete support, combined anchor-mesh-shotcrete support, and steel arch support. All three technologies have significant drawbacks under high water-soaking conditions.

[0004] When shotcrete supports are subjected to water spraying from the roof slab, the water flow disperses the uncured concrete slurry, making it difficult for the sprayed layer to adhere stably to the roof slab. This can easily cause the entire layer to fall off, preventing the formation of a complete and sealed waterproof support layer.

[0005] Traditional anchor-mesh shotcrete support is also subject to water erosion, resulting in a significant decrease in the bonding performance between concrete and surrounding rock and anchor mesh. Frequent occurrences of hollowing, cracking, and detachment of the sprayed layer necessitate multiple re-spraying repairs, which involve complex procedures and high consumption of manpower and materials.

[0006] The on-site assembly and fixing of steel arch support is cumbersome. The steel is prone to rust and failure when immersed in water for a long time, and the overall investment in rust removal, reinforcement and maintenance is high.

[0007] Existing support techniques cannot fundamentally solve the problems of water seepage and erosion, and their construction efficiency is low, posing safety hazards. Therefore, it is necessary to develop new roadway support and treatment methods that are suitable for high water seepage roadways, easy to construct, have excellent waterproof support effects, and are highly economical. Summary of the Invention

[0008] To address the shortcomings of existing technologies, the purpose of this invention is to provide a combined support and treatment method for water seepage areas in mine tunnel roofs. Utilizing the water-resistant properties of flexible cement blankets that rapidly solidify upon contact with water, and combined with anchor mesh to construct a composite support system, this method simultaneously achieves both surrounding rock reinforcement and water seepage prevention, shortening the construction period, reducing overall costs, and improving the safety level of underground operations.

[0009] The technical solution adopted by this invention to solve its technical problem is:

[0010] A method for combined support and management of water seepage areas in mine tunnel roofs employs a closed-loop operation process. First, geological and water seepage condition surveys are conducted in the underground water-seeping tunnels, collecting data on surrounding rock lithology, rock mass fracture development parameters, roof water seepage flow rate, and water corrosivity indicators. The critical scour intensity threshold is determined, and traditional support failure criteria are established, providing a basis for support material selection and construction process design. Next, composite support material selection and proportion optimization are performed, selecting cement blanket substrate, threaded steel anchor bolts, and metal anchor mesh. The formula for rapid-hardening sulfoaluminate cement-based cement blanket and the dosage of functional waterproofing additives are determined, and indoor impermeability, tensile strength, and scour resistance tests are conducted to verify material compatibility. Finally, the combined support structure and construction scheme are designed, constructing a composite support system with an anchor mesh framework and a cement blanket waterproofing layer, setting anchor bolt placement parameters, and installing PVC... The diversion pipe implements segmented water diversion and control of the roof, and standardized operation procedures for cement blanket cutting, fixing, and water spraying curing are developed. Subsequently, numerical simulation and parameter verification of the support effect are carried out, and a coupled model of roadway surrounding rock and composite support is built. Traditional anchor mesh spraying support model and cement blanket composite support model are constructed respectively. The range of loosening zone of surrounding rock, seepage pressure of support layer, and interface debonding risk are compared under long-term water spraying conditions to determine the overlap width and anchor bolt arrangement parameters. Then, standardized on-site construction operations and full-process monitoring are carried out in the mine. The roof rock cleaning, cement blanket binding and laying, water diversion treatment, anchor mesh laying and fixing, and water spraying curing operations are completed in sequence. After the support operation is completed, continuous monitoring is carried out to collect data on roof deformation, water spraying volume, cement blanket cracking and leakage, and interface bonding status. Local support parameters are adjusted based on the collected data.

[0011] Furthermore, after the critical scour intensity threshold of water spraying is obtained through surveying, the cement blanket composite support system is activated when the water spraying flow reaches the critical scour intensity threshold. In areas with severe water spraying conditions where the water spraying flow exceeds the critical scour intensity threshold, a double-layer cement blanket overlapping structure is adopted.

[0012] Furthermore, the cement blanket has a three-layer composite structure: the bottom layer is a waterproof PVC layer, the middle layer is a three-dimensional polypropylene fiber matrix filled with fast-hardening cement powder, and the surface layer is a permeable mesh fabric. The layers are woven together with high-strength spacer yarns.

[0013] Furthermore, the cement blanket is bound and fixed to the surface of the metal anchor mesh with high-strength galvanized iron wire. Adjacent cement blankets are connected by an overlapping structure. PVC diversion pipes are laid along the water-spraying cracks in the roof. The ends of the PVC diversion pipes are connected to the underground drainage system of the roadway. The PVC diversion pipes divert water to prevent water from directly washing the surface of the cement blanket in the uncured state.

[0014] Furthermore, in the numerical simulation and parameter verification of the support effect, the numerical simulation model is configured with non-reflective boundary conditions.

[0015] Furthermore, the water spraying and curing operation is maintained for a fixed duration, and the operation continuously monitors and collects data on roof convergence displacement, water spray volume in the roadway, surface integrity of the cement blanket, and bonding density between the cement blanket and the surrounding rock. The support operation is deemed to be up to standard if it meets the conditions of reduced water spray volume, no cracking or leakage, and no bulging or falling off at the interface.

[0016] Furthermore, the composite support system achieves a triple synergistic effect: the cement blanket solidifies into a dense water-proof barrier to achieve water sealing; the solidified cement blanket adheres to the surrounding rock to jointly bear pressure and absorbs the deformation energy of the surrounding rock through flexible deformation to achieve mechanical support; and the cement blanket, together with anchor bolts and metal anchor mesh, is tightly integrated to form a whole to achieve bonding and reinforcement.

[0017] Furthermore, the combined support and treatment method is used for support and treatment operations in underground roadways of metal mines where fractures are continuously developed and there is continuous roof water seepage.

[0018] The present invention, which adopts the above technical solution, has the following prominent features compared with the prior art:

[0019] 1. Excellent waterproofing and sealing performance: The cement blanket solidifies to form a dense composite waterproof layer, reducing water seepage from the roof slab and reducing water erosion and scouring of the surrounding rock and support structure from the source, thus solving the problem of grout detachment in high water seepage conditions.

[0020] 2. High stability of the support system: The anchor mesh provides rigid skeleton support, and the cement blanket flexibly adheres to the roof to absorb the deformation stress of the surrounding rock. The combination forms a composite support system that has water-proof, tensile, and crack-resistant properties, reducing the risk of roof collapse and sidewall spalling.

[0021] 3. High construction efficiency: The finished cement blanket is a flexible roll material that can be directly cut on site. It does not require on-site concrete mixing and eliminates multiple spraying operations. The overall construction time is significantly shortened compared to the traditional anchor mesh spraying process, reducing repetitive work by equipment and personnel.

[0022] 4. Outstanding overall economic benefits: It saves a lot of sprayed concrete consumables and re-spraying labor, reducing the overall cost of support.

[0023] 5. It has a wide range of applications and can be adapted to fractured water-leaking surrounding rock. The construction process is standardized and can be widely applied to the treatment of water-leaking tunnels in underground mines such as iron ore and non-ferrous metal mines.

[0024] 6. Low maintenance workload: Cement blankets are impermeable, erosion resistant, and anti-aging. After curing, they will not detach or peel off, reducing tunnel repair and respraying operations and lowering long-term operation and maintenance costs. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the main structure after the support is completed according to an embodiment of the present invention;

[0026] Explanation of reference numerals in the attached diagram: 1. Cement blanket; 2. Anchor bolt; 3. Anchor mesh; 4. PVC diversion pipe. Detailed Implementation

[0027] The present invention will be further illustrated below with reference to specific embodiments. The purpose of this illustration is solely to provide a better understanding of the invention. Therefore, the examples given do not limit the scope of protection of the present invention.

[0028] like Figure 1 As shown in the figure, this embodiment presents a combined support and treatment method for water seepage areas in mine tunnel roofs. Geological and water seepage conditions of the underground water seepage roadway are surveyed, and parameters such as the compressive strength of the surrounding rock, the crack spacing, and the corrosivity of the water are collected on site. The water seepage flow rate is measured, and it is determined that traditional shotcrete and anchor mesh shotcrete support cannot be stably formed. Therefore, a double-layer cement blanket composite support scheme is selected.

[0029] The selection and proportion optimization of composite support materials were carried out, and a three-layer composite structure cement blanket 1 with a thickness of 10mm and a surface density of 10kg / m² was selected. The base material is composed of rapid-hardening sulfoaluminate cement combined with polypropylene fiber, and the bottom layer is equipped with a PVC waterproof layer. Threaded steel anchor rods 2 were selected, along with metal welded anchor mesh 3, galvanized binding wire, and PVC drainage pipes 4. Indoor impermeability, tensile strength, and erosion resistance tests were conducted to verify that the materials are suitable for heavy water seepage conditions underground and that the materials' resistance to mine water corrosion meets the usage requirements.

[0030] The design of the joint support structure and construction plan was carried out, and a composite support system with anchor mesh 3 skeleton and cement blanket 1 waterproof layer was constructed. The spacing of anchor rod 2 was set, double layer cement blanket 1 was laid, and cement blanket 1 overlap structure was set. PVC diversion pipe 4 was arranged along the water outlet crack of the roof, and the diversion channel was connected to the roadway drainage system to continuously divert the water inflow during the construction stage and avoid water splashing and erosion of the cement blanket 1 that has not yet cured. Standardized operation procedures for cutting, binding and fixing, and watering curing of cement blanket 1 were compiled.

[0031] Numerical simulation and parameter verification of the support effect were carried out, and a coupled model of composite support for roadway surrounding rock was built. The surrounding rock was set with a Mohr-Coulomb constitutive model, and the cement blanket 1 was set with an elastoplastic constitutive model. The model was configured with non-reflective boundary conditions. The traditional anchor mesh 3 shotcrete working condition and the cement blanket 1 composite support working condition were simulated respectively. The range of loosening zone of surrounding rock, seepage pressure of support layer and interface debonding risk were compared to confirm that the arrangement of anchor bolts 2 and the overlapping structure of cement blanket 1 can meet the requirements of stable operation under long-term water spraying conditions.

[0032] Conduct standardized on-site construction operations and full-process monitoring in the mine:

[0033] The first step is to complete the removal of loose rocks and dangerous rocks from the roof, and to level the working surface.

[0034] The second step is to lay the cement blanket 1. Cut the roll material according to the actual size of the roof slab, lay it in two layers, and use galvanized iron wire to tie and fix it above the metal anchor mesh 3.

[0035] The third step is to complete the water diversion operation and install PVC diversion pipe 4 to divert water gushing from the top slab;

[0036] The fourth step involves the construction of anchor mesh 3, including drilling, installation of anchor bolts 2, laying of metal anchor mesh 3, and tensioning and fixing it.

[0037] The fifth step is to carry out water spraying and curing operations to ensure that the cement blanket 1 is fully hydrated and solidified.

[0038] After the support work was completed, continuous monitoring was initiated to continuously collect data related to roof convergence displacement, tunnel water seepage, surface integrity of cement blanket 1, and bonding density between cement blanket 1 and the surrounding rock. At the end of the monitoring period, no significant displacement or deformation was observed in the roof, the tunnel water seepage was significantly reduced, the surface of cement blanket 1 was smooth, and there were no cracks, leaks, bulges, or detachments. Cement blanket 1 was firmly bonded to the surrounding rock and anchor mesh 3, and the support work was deemed satisfactory.

[0039] Effect comparison: Traditional anchor mesh 3-shot support includes initial shotcrete and re-shotcrete processes, and the construction time for a single section of roadway is relatively long; the construction time of the combined support in this implementation case is significantly shortened; the annual treatment operation saves on the comprehensive investment of materials, labor and equipment; eliminates the safety hazards of shotcrete layer detachment and roof collapse, improves the roadway working environment, and reduces the probability of underground safety accidents.

[0040] The above description is merely a preferred embodiment of the present invention and does not limit the scope of the present invention. All equivalent changes made based on the description and drawings of the present invention are included within the scope of the present invention.

Claims

1. A method for combined support and treatment of water seepage areas in mine tunnel roofs, comprising implementing surrounding rock support operations on the roof of water seepage roadways in iron mines, characterized in that, To implement the closed-loop operation process, the geological and water-spraying conditions of the underground water-spraying roadway are first surveyed. The lithology of the surrounding rock, parameters of rock mass fissure development, water-spraying flow rate of the roof, and water quality corrosivity index are collected. The critical scouring strength threshold of water-spraying is determined, the failure judgment criteria of traditional support are established, and the basis for the selection of support materials and the basis for construction process design are output. Subsequently, the selection and ratio optimization of composite support materials were carried out. Cement blanket substrate, threaded steel anchor rod, and metal anchor mesh were selected. The formula of rapid hardening sulfoaluminate cement-based cement blanket and the dosage of functional waterproofing additives were determined. Indoor impermeability, tensile strength, and erosion resistance tests were carried out to verify the material compatibility. Subsequently, the design of the joint support structure and construction plan was carried out, a composite support system with anchor mesh skeleton and cement blanket waterproof layer was constructed, anchor bolt layout parameters were set, PVC diversion pipes were laid to implement water diversion and control in stages on the top plate, and standardized operation procedures for cement blanket cutting, fixing, watering and curing were compiled. Subsequently, numerical simulation and parameter verification of the support effect were carried out. A coupled model of roadway surrounding rock and composite support was built. Traditional anchor mesh spraying support model and cement blanket composite support model were constructed respectively. The range of loosening zone of surrounding rock, seepage pressure of support layer and interface debonding risk were compared under long-term water spraying conditions to determine the overlap width and anchor bolt arrangement parameters. Subsequently, standardized on-site construction operations and full-process monitoring were carried out in the well. The following steps were completed in sequence: cleaning of unstable roof rock, binding and laying of cement blanket, water diversion treatment, laying and fixing of anchor mesh, and water curing. After the support operation was completed, continuous monitoring was carried out to collect data on roof deformation, water volume, cement blanket cracking and leakage, and interface bonding status. Based on the collected data, local support parameters were adjusted.

2. The method for combined support and treatment of water seepage areas in the mine roof according to claim 1, characterized in that: After the critical scour intensity threshold of water spraying is obtained through surveying, the cement blanket composite support system is activated when the water spraying flow reaches the critical scour intensity threshold. In areas with severe water spraying conditions where the water spraying flow exceeds the critical scour intensity threshold, a double-layer cement blanket overlapping structure is adopted.

3. The method for combined support and treatment of water seepage areas in the mine roof according to claim 1, characterized in that: The cement blanket has a three-layer composite structure: the bottom layer is a waterproof PVC layer, the middle layer is a three-dimensional polypropylene fiber matrix filled with fast-hardening cement powder, and the surface layer is a permeable mesh fabric. The layers are woven together with high-strength spacer yarns.

4. The method for combined support and treatment of water seepage areas in the mine roof according to claim 1, characterized in that, The cement blanket is bound and fixed to the surface of the metal anchor mesh with high-strength galvanized iron wire. Adjacent cement blankets are connected by an overlapping structure. PVC diversion pipes are laid along the water-spraying cracks in the roof. The ends of the PVC diversion pipes are connected to the underground drainage system of the roadway. The PVC diversion pipes divert water to prevent water from directly washing the surface of the cement blanket in the uncured state.

5. The method for combined support and treatment of water seepage areas in the mine roof according to claim 1, characterized in that: In the numerical simulation and parameter verification of support effect, the numerical simulation model is configured with non-reflective boundary conditions.

6. The method for combined support and treatment of water seepage areas in the mine roof according to claim 1, characterized in that: The water spraying and curing operation is maintained for a fixed duration. The operation continuously monitors and collects data on roof convergence displacement, water spray volume in the roadway, surface integrity of the cement blanket, and bonding density between the cement blanket and the surrounding rock. The support operation is deemed to be up to standard if it meets the conditions of reduced water spray volume, no cracking or leakage, and no bulging or falling off at the interface.

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