A rigid and flexible blocking method for water in tailings pond flood discharge channel

Abstract

The present invention discloses a method for sealing a tailings pond flood discharge channel with water by combining rigidity and flexibility. A grouting sealing section (8), a flexible sealing body section, and a permanent structural sealing body section are successively arranged in the tailings pond flood discharge channel from the inside to the outside. The permanent structural sealing body section is composed of a concrete section (7) and retaining walls (5) located on both sides of the concrete section (7). A filter layer (1) of not less than 1 m is arranged upstream of the permanent structural sealing body section. Grouting is performed in sections in the flood discharge channel using cement tailings mortar through three pre-buried grouting pipes (4) of different lengths to form a grouting sealing section (8). The method for sealing a tailings pond flood discharge channel with water by combining rigidity and flexibility effectively utilizes the principle of "dredging first and then blocking". The method is simple, highly practical, highly professional in blocking, and has low engineering cost. It can ensure the safe operation of the tailings pond and avoid potential safety hazards caused by failure of the flood discharge system blocking.

Description

Technical Field

[0001] The present invention belongs to the technical field of plugging of mine tailings pond drainage systems, and specifically relates to a method for plugging tailings pond drainage channels. The method can be widely used in plugging drainage channels of large and medium-sized ferrous and non-ferrous tailings ponds, and is particularly suitable for plugging old tailings pond drainage systems. Background Art

[0002] The tailings pond's drainage system consists of two parts: an internal drainage system and an external drainage system. The internal drainage system includes inlet and outlet structures. Inlet structures are typically drainage wells or chutes, while outlet structures are typically drainage culverts, pipes, and other channels. In addition to intercepting ditches, the external drainage system also features spillways leading to return water tanks or flood control outlets.

[0003] The flood drainage system is extremely important for tailings ponds. During operation, it must not only ensure flood control safety, but also ensure that tailings in the pond do not leak through the flood drainage system. Therefore, the flood drainage system must be immediately sealed after it is no longer in use.

[0004] The sealing of tailings pond drainage systems generally only applies to the drainage system within the pond. Currently, there are two methods for sealing tailings pond drainage systems: rigid sealing and flexible sealing. Rigid sealing uses rigid materials such as concrete and requires a tight seal. Engineering applications have shown that rigid sealing is not ideal and is prone to failure. Flexible sealing uses the principle of "hydraulic filtration" to control seepage damage. Specifically, it uses filtration materials to seal the seepage area, effectively intercepting tailings. Over time, the tailings will gradually settle, the permeability of the seal will decrease, and the amount of seepage will decrease, achieving a gradual sealing effect.

[0005] The February 2018 publication of "Engineering Technology and Applications" titled "Research on Sealing Methods for Tailings Pond Drainage Systems" introduced the structural types of tailings pond drainage system seals. These seals are categorized by material: ① Rigid structures, including mortared stone, concrete, and reinforced concrete; ② Granular structures, consisting of stone, crushed stone, gravel, sand, geotextiles, or geomembranes; and ③ Paste structures, consisting of high-water-density materials, coarse tailings, and water. Furthermore, these seals are categorized by structural type: ① Beam-slab seals; ② Shear seals; ③ Gravity seals; ④ Filter seals; and ⑤ Paste seals.

[0006] Most tailings pond drainage systems operate under high water pressure before being sealed. Traditional construction methods struggle to meet these sealing requirements, and the sealing element must withstand the immense pressure of high water heads to ensure the safety and stability of the tailings pond after the drainage system is sealed. If the sealing fails, the tailings pond faces significant safety risks. Summary of the Invention

[0007] The purpose of the present invention is to provide a rigid and flexible sealing method for water in the tailings pond discharge channel that is convenient to construct, economical and effective, safe and stable, in order to address the technical difficulties existing in the prior art, such as poor sealing effect, easy sealing failure or high sealing cost.

[0008] To achieve the above-mentioned purpose of the present invention, a method for rigid and flexible sealing of water in a tailings pond drainage channel of the present invention is implemented by the following technical solutions:

[0009] The present invention provides a method for rigid and flexible plugging of water in a tailings pond drainage channel. A grouting plugging section, a flexible plugging body section, and a permanent structural plugging body section are successively arranged from the inside to the outside of the tailings pond drainage channel. The permanent structural plugging body section is composed of a concrete section and retaining walls located on both sides of the concrete section. The method is implemented by the following technical solutions:

[0010] S1: Flexible blocking at the outlet of the flood discharge channel

[0011] Step 1: Calculate the length of the permanent structural blocking section at the outlet of the flood discharge channel according to the "Design Code for Hydraulic Tunnels" (SL279-2016), which is recorded as 1L.

[0012] Step 2: Set up a filter layer of no less than 1m in thickness upstream of the permanent structural plugging body section. The filter layer is made of geotextile wrapped gravel. The filter layer is the flexible plugging body section.

[0013] Step 3: Lay out three water pipes at the bottom of the flood discharge channel, connecting the filter layer to the outlet of the flood discharge channel;

[0014] S2: Permanent structural blocking at the outlet of the flood discharge channel

[0015] Step 1: Pre-buried three grouting pipes of different lengths at the top of the flood drainage channel, passing through the permanent structural plugging body section and the flexible plugging body section. The lengths of the three grouting pipes are 1.4-1.7L, 2.8-3.5L, and 5.2-6.8L respectively. At the same time, pre-buried an exhaust pipe at the top of the flood drainage channel.

[0016] Step 2: Set up a retaining wall at the upstream of the concrete section where it connects to the filter layer;

[0017] Step 3: Set up another retaining wall at the outlet of the flood discharge channel downstream of the concrete section, and pre-embed a pouring pipe in the middle of the retaining wall. Use the pouring pipe to pour concrete into the middle cavity of the two retaining walls in the flood discharge channel to form a concrete section.

[0018] S3: Grouting and plugging

[0019] Through three pre-buried grouting pipes of varying lengths, cement tailings mortar with water glass was injected into the flood discharge channel in sections, forming grouting plugging sections. During the grouting process, exhaust was exhausted through an exhaust pipe pre-buried at the top of the flood discharge channel.

[0020] Furthermore, the cement tailings mortar is made by mixing cement, tailings, water and water glass. The proportion of the cement tailings mortar when the total mass is calculated as 100% is: cement 18% to 30%, tailings 55% to 66%, water 11% to 16%, and water glass 3% to 4%.

[0021] The experimental results show that in step S2, the best concrete to be cast is C30 self-compacting concrete. 3 The mass ratio of self-compacting concrete is: 175-185kg of water, 230-250kg of 425 cement, 125-135kg of slag powder, 125-135kg of fly ash, 770-790kg of sand, 240-260kg of 5-15mm gravel, 570-590kg of 15-31.5mm gravel, and 6.0-6.5kg of water reducer.

[0022] In order to improve the blocking effect and efficiency of the method of the present invention, in step S1, the geotextile used in the filter layer has a specification of 350-500 g / m 2 The crushed stone is melon seed-like pieces with a particle size of 5 to 10 mm.

[0023] Furthermore, in step S1, the specification of the water pipe is 70-85 mm in Φ; in step S2, the specifications of the three grouting pipes of different lengths are 70-85 mm in Φ; the specification of the exhaust pipe is 45-60 mm in Φ; and the specification of the casting pipe is 140-160 mm in Φ.

[0024] Studies have shown that when the length of the grouting sealing section is ≥ 3 times the length of the permanent structure sealing body section, the sealing effect and construction cost are better.

[0025] Furthermore, the tailings in the cement tailings mortar used in step S3 are taken from the tailings in the tailings pond, and the grouting and plugging in step S3 adopts a double-liquid grouting method.

[0026] As a preferred embodiment of the method of the present invention, in step S3, grouting is performed in sections from bottom to top under pressure through three pre-buried grouting pipes of different lengths.

[0027] The rigid and flexible plugging method for water in the tailings pond flood discharge channel of the present invention adopts the above technical solution, which has the following positive effects:

[0028] (1) The method of the present invention adopts a combination of rigid blocking and flexible blocking, effectively applies the principle of "dredging first and then blocking", and has high blocking efficiency.

[0029] (2) The method of the present invention uses mostly tailings in the reservoir as materials, which can be taken out immediately after use, and is convenient and quick to seal. The engineering cost is low, and the tailings in the reservoir can be effectively utilized, thereby reducing the storage capacity of part of the tailings reservoir and achieving significant economic benefits.

[0030] (3) The blocking length of the method of the present invention is much longer than the standard length, which is safe and reliable and can effectively avoid the safety hazards caused by blocking failure. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 A cross-sectional structural diagram of the flood discharge channel plugging designed and developed for the method of the present invention;

[0032] Figure 2 The present invention is a flow chart of grouting and blocking flood discharge channels using the method of the present invention.

[0033] Figure numbers: 1-filter layer; 2-water pipe; 3-exhaust pipe; 4-grouting pipe; 5-retaining wall; 6-casting pipe; 7-concrete section; 8-grouting sealing section. DETAILED DESCRIPTION

[0034] To further describe the present invention, a rigid and flexible sealing method for water-carrying tailings pond flood discharge channel according to the present invention is described in further detail below with reference to the accompanying drawings.

[0035] Depend on Figure 1 As shown in the cross-sectional structural diagram of the drainage channel plugging designed by the method of the present invention, a rigid and flexible plugging method for a tailings pond drainage channel with water is provided in the tailings pond drainage channel. A grouting plugging section 8, a flexible plugging body section, and a permanent structural plugging body section are successively arranged from the inside to the outside. The permanent structural plugging body section is composed of a concrete section 7 and retaining walls 5 located on both sides of the concrete section 7, and is implemented using the following technical solutions:

[0036] S1: Flexible blocking at the outlet of the flood discharge channel

[0037] Step 1: Calculate the length of the permanent structural blocking section at the outlet of the flood discharge channel according to the "Design Code for Hydraulic Tunnels" (SL279-2016), which is recorded as 1L.

[0038] Step 2: Set up a 1m long filter layer 1 upstream of the permanent structural plugging body section. The filter layer 1 is made of geotextile wrapped with gravel. The filter layer 1 is the flexible plugging body section. The geotextile used in the filter layer 1 is 400g / m 2 , the crushed stone is melon seed pieces with a particle size of 5 to 10 mm;

[0039] Step 3: Lay three water pipes 2 at the bottom of the flood drainage channel. The water pipes 2 are DN75HDPE pipes, and the specification of the water pipes 2 is Φ75mm; the water pipes 2 connect the filter layer 1 to the outlet of the flood drainage channel.

[0040] S2: Permanent structural blocking at the outlet of the flood discharge channel

[0041] Step 1: Pre-buried three grouting pipes 4 of different lengths at the top of the flood drainage channel, passing through the permanent structural plugging body section and the flexible plugging body section. The three grouting pipes 4 of different lengths are 1.5L, 3L, and 6L respectively, extending from the outlet of the flood drainage channel to the interior; at the same time, pre-buried an exhaust pipe 3 at the top of the flood drainage channel. The exhaust pipe 3 uses a DN50 PVC pipe; the three grouting pipes 4 of different lengths have a Φ of 75mm, and the exhaust pipe 3 has a Φ of 50mm;

[0042] Step 2: Install a retaining wall 5 at the upstream of the concrete section 7 where it connects to the filter layer 1. The retaining wall 5 is made of bricks.

[0043] Step 3: Build another retaining wall 5 at the outlet of the flood discharge channel downstream of the concrete section 7, and pre-embed a pouring pipe 6 in the middle of the retaining wall 5. The pouring pipe 6 has a specification of Φ150mm. Use SA-008 fine stone concrete pump to pump concrete. Use the pouring pipe 6 to cast concrete in the cavity in the middle of the two retaining walls 5 in the flood discharge channel to form a concrete section 7.

[0044] A concrete mixer truck is used to mix the concrete. The C30 self-compacting concrete mix is ​​shown in Table 1:

[0045] Table 1C30 self-compacting concrete mix ratio (kg / m 3 )

[0046]

[0047] S3: Grouting and plugging

[0048] Through three pre-buried grouting pipes 4 of different lengths, cement tailings mortar with water glass added is used to carry out grouting in sections in the flood discharge channel to form a grouting sealing section 8. The length of the grouting sealing section 8 is ≥ 3 times the length of the permanent structural sealing body section; the tailings in the cement tailings mortar used are taken from the tailings in the tailings pond.

[0049] Depend on Figure 2 As shown in the flowchart of the method of the present invention for grouting and plugging the flood discharge channel, in step S3, the construction is completed in the following order:

[0050] Step 1: Use a mixer to mix the cement tailings slurry according to the designed mix ratio.

[0051] Examples 1-6 present the results of indoor testing of grouting materials used in a method for rigid and flexible sealing of flooded tailings pond drainage channels according to the present invention. According to the "Concrete Quality Control Standard" (GB50164-2011), Examples 1-6 meet the T3 grade, with slumps greater than 100 mm and fluidity. The proportions of cement tailings mortars in Examples 1-6, measured by weight, are shown in Table 2:

[0052] Table 2 Cement tailings mortar ratio

[0053]

[0054] Step 2: Place the prepared cement tailings slurry in the water reservoir after filtering; place the water glass chemical slurry in the slurry storage barrel, and inject them into the dual-liquid grouting pump ZBYSB500 / 10-45 through the slurry pipeline.

[0055] Step 3: When grouting is required, start the grouting pump, open the valves on the two pipelines of the grouting pump at the same time, connect the mixer, and inject the cement tailings mortar (with water glass added) 8 into the grouting pipe 4 and spray it into the flood discharge channel; carry out grouting and sealing in stages from short to long and from bottom to top under pressure according to the length of the grouting pipe.

[0056] In step S3, grouting and plugging adopts a double-liquid grouting method, and grouting is performed in sections from bottom to top under pressure through three pre-buried grouting pipes 4 of different lengths.

[0057] The rigid and flexible sealing method for water-carrying tailings pond drainage channel of the present invention has been applied in the design and construction of the sealing of an old drainage system of a certain lead-zinc mine. It has good sealing effect, low project cost, strong practicality, ensures the safety of the tailings pond, and avoids safety hazards caused by failure of the drainage system sealing.

Claims

1. A rigid and flexible sealing method for water in a tailings pond drainage channel, characterized by: A grouting plugging section (8), a flexible plugging body section, and a permanent structural plugging body section are successively arranged from the inside to the outside of the tailings pond flood discharge channel. The permanent structural plugging body section is composed of a concrete section (7) and retaining walls (5) located on both sides of the concrete section (7). The length of the grouting plugging section (8) is ≥ 3 times the length of the permanent structural plugging body section. The following technical solution is adopted for implementation: S1: Flexible blocking at the outlet of the flood discharge channel Step 1: Calculate the length of the permanent structural blocking section at the outlet of the flood discharge channel according to the "Code for Design of Hydraulic Tunnels" (SL279-2016), which is recorded as 1L; Step 2: Set up a filter layer (1) of not less than 1m upstream of the permanent structural plugging body section. The filter layer (1) is made of crushed stone wrapped with geotextile. The filter layer (1) is the flexible plugging body section. The geotextile used in the filter layer (1) has a specification of 350~500g / m 2 , the crushed stone is melon seed pieces with a particle size of 5~10mm; Step 3: Lay out three water pipes (2) at the bottom of the flood discharge channel, wherein the water pipes (2) connect the filter layer (1) to the outlet of the flood discharge channel; the water pipes (2) have a specification of Φ of 70-85 mm; S2: Permanent structural blocking at the outlet of the flood discharge channel The first step is to pre-bury three grouting pipes (4) of different lengths at the top of the flood discharge channel, passing through the permanent structural plugging body section and the flexible plugging body section. The lengths of the three grouting pipes (4) of different lengths are 1.4 to 1.7 L, 2.8 to 3.5 L, and 5.2 to 6.8 L, respectively. At the same time, one exhaust pipe (3) is pre-buried at the top of the flood discharge channel. The three grouting pipes (4) of different lengths have a specification of Φ of 70 to 85 mm. The exhaust pipe (3) has a specification of Φ of 45 to 60 mm. Step 2: Install a retaining wall (5) at the upstream of the concrete section (7) where it connects to the filter layer (1); the concrete section (7) is cast with C30 self-compacting concrete, with a thickness of 1 / m 3 The mass ratio of self-compacting concrete is: 175-185 kg of water, 230-250 kg of 425 cement, 125-135 kg of slag powder, 125-135 kg of fly ash, 770-790 kg of sand, 240-260 kg of 5-15 mm crushed stone, 570-590 kg of 15-31.5 mm crushed stone, and 6.0-6.5 kg of water reducer. Step 3: Set up another retaining wall (5) downstream of the concrete section (7) to the outlet of the flood discharge channel, and pre-embed a pouring pipe (6) in the middle of the retaining wall (5), the pouring pipe (6) having a specification of Φ of 140-160 mm, and use the pouring pipe (6) to cast concrete in the cavity in the middle of the two retaining walls (5) in the flood discharge channel to form a concrete section (7); S3: Grouting and plugging Through three pre-buried grouting pipes (4) of different lengths, cement tailings mortar is used to perform grouting in sections in the flood discharge channel to form a grouting plugging section (8); the cement tailings mortar is made by mixing cement, tailings, water, and water glass, and the proportion of the cement tailings mortar when the total mass is calculated as 100% is: cement 18% to 30%, tailings 55% to 66%, water 11% to 16%, and water glass 3% to 4%.

2. A method for rigid and flexible sealing of water in a tailings pond drainage channel according to claim 1, characterized in that: The tailings in the cement tailings slurry used in step S3 are taken from the tailings in the tailings pond.

3. The method for rigid and flexible sealing of water in a tailings pond drainage channel according to claim 2, characterized in that: In step S3, the grouting and plugging adopts the double-liquid grouting method.

4. A method for rigid and flexible sealing of water in a tailings pond drainage channel according to claim 3, characterized in that: In step S3, grouting is performed in sections from bottom to top under pressure through three pre-buried grouting pipes (4) of different lengths.

5. A method for rigid and flexible sealing of water in a tailings pond drainage channel according to claim 4, characterized in that: In step S1, the geotextile used in the filter layer (1) is 400g / m 2 , the water pipe (2) has a specification of Φ of 75 mm; in step S2, the lengths of the three grouting pipes (4) of different lengths are 1.5 L, 3.0 L, and 6.0 L respectively, the grouting pipe (4) has a specification of Φ of 75 mm, the exhaust pipe (3) has a specification of Φ of 50 mm, and the pouring pipe (6) has a specification of Φ of 150 mm.

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