Tailing pond underground diaphragm wall grooving and quincunx curtain grouting synergistic process

Abstract

The invention discloses a tailing pond underground anti-seepage wall grooving and quincunx curtain grouting synergistic process, and relates to the technical field of grouting collaboration.The tailing pond underground anti-seepage wall grooving and quincunx curtain grouting synergistic process comprises the following steps that S1, anti-seepage wall bodies are constructed in a foundation of a to-be-treated area, the anti-seepage wall bodies are continuously arranged along the treatment axis, a wall body groove section is formed through the underground grooving technology, and the wall body groove section is formed; s2, curtain grouting treatment is synchronously or firstly carried out on the lower area or the upstream side of the anti-seepage wall body, a multi-row sequential hole arrangement mode is adopted for curtain grouting, grouting holes are arranged in a staggered or quincuncial mode, a continuous curtain anti-seepage layer is formed, and the anti-seepage wall body is formed; and S3, the anti-seepage wall and the curtain grouting bodies are provided with lap joint areas in the vertical direction or the horizontal direction, and a wall-curtain integrated anti-seepage structure is formed. The plastic concrete anti-seepage wall is constructed in the foundation, the multiple rows of quincunx curtain grouting bodies are arranged in the foundation, and the lap joint structures are arranged between the plastic concrete anti-seepage wall and the multiple rows of quincunx curtain grouting bodies; unification of structural stability and anti-seepage continuity of the underground anti-seepage system is achieved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of grouting, in particular to a tailing pond underground diaphragm wall trenching and plum blossom curtain grouting synergistic process. BACKGROUND

[0002] The tailing pond, as an important waste storage and management facility of mining enterprises, has always been one of the main hidden dangers of environmental pollution and safety accidents. In the prior art, patent No. 202211197379.0, the invention name is a flexible anti-seepage structure combined with diaphragm wall and curtain grouting and its construction method, which can form a continuous and seamless anti-seepage structure in the overburden layer and the bedrock layer. Under the condition of not affecting the normal operation of the tailing pond or the landfill, the leakage problem in the overburden layer and the deep bedrock fissure is solved, and the leakage liquid is prevented from seeping outward through the wall joint. At the same time, the flexibility of the anti-seepage wall and the anti-seepage curtain makes them have certain deformation ability, avoiding the cracking and damage of the wall caused by external force.

[0003] Traditional tailing pond anti-seepage treatment measures often use single curtain grouting or underground diaphragm wall method, but in the working conditions of weathered bedrock shallow overburden, complex leakage path and frequent water level fluctuation, single technology often faces problems such as incomplete leakage plugging, difficult construction and poor water control effect. Especially in old tailing ponds, the original anti-seepage system may not be set or has aged and failed, and the pollution plume is easy to break through the curtain or flow around the wall boundary, causing secondary pollution to the surrounding water and soil. Therefore, there is an urgent need for a comprehensive process that combines the stability of diaphragm wall trenching structure and the adjustability of curtain grouting to improve the anti-seepage performance of the tailing pond bottom and downstream area, and to effectively block the pollution migration and long-term stable control of hydrological conditions. SUMMARY

[0004] The present application provides a tailing pond underground diaphragm wall trenching and plum blossom curtain grouting synergistic process, which can effectively solve the problems raised in the background art.

[0005] To achieve the above purpose, the present application provides the following technical scheme: a tailing pond underground diaphragm wall trenching and plum blossom curtain grouting synergistic process, comprising the following steps: S1, constructing a diaphragm wall body in the foundation of the area to be treated, the diaphragm wall body is continuously arranged along the treatment axis, the underground trenching technology is used to form a wall body slot section, and the anti-seepage material is poured in the slot to form the diaphragm wall; S2, simultaneously or in advance, implementing curtain grouting treatment in the lower part of the diaphragm wall body or the upstream side thereof, the curtain grouting adopts a multi-row and sequence hole arrangement mode, the grouting holes are arranged in a staggered or plum blossom shape, and a continuous curtain anti-seepage layer is formed; S3, the diaphragm wall and the curtain grouting body are provided with a lap area in the vertical direction or the horizontal direction, forming a wall-curtain integrated anti-seepage structure.

[0006] According to the technical scheme, the S1 impermeable wall body material comprises plastic concrete or low-permeability, foundation-deformation-adaptable impermeable material; The curtain grouting adopts cement, water glass, bentonite slurry or other grouting materials, which are selected according to geological conditions; The overlapping area is optionally provided with grouting holes or a reinforcing layer.

[0007] According to the technical scheme, the plastic concrete material of the S1 impermeable wall body comprises a proportioning system with a mass ratio of cement:bentonite:fine sand:water = 1:(0.5-1.0):(2.5-3.5):(1.5-2.5), and the mixture requires that the 28-day compressive strength is greater than or equal to 2.5 MPa, the elastic modulus is less than or equal to 2000 MPa, and the permeability coefficient is less than or equal to 1×10 -6 cm / s.

[0008] According to the technical scheme, the underground trenching technology in the S1 is a rotary drilling method, which realizes effective connection between multiple trenching sections by first arranging main holes, then arranging auxiliary holes, and then adopting interval and sequence trenching and continuous direct pipe pouring processes.

[0009] According to the technical scheme, the S1 constructs a wall-curtain combined impermeable system in the downstream direction of the pollution plume during construction according to the site hydrogeological conditions and the pollution migration path, and realizes hydraulic blockage of the pollution plume and formation of a reverse concentration gradient by arranging special underground water extraction wells or leachate drainage wells for induced extraction. The extraction well spacing is arranged according to the stratum permeability coefficient and the pollution migration speed, and the recommended spacing is 10-20 meters, and the well depth is adjusted to 10-30 meters according to the pollution layer depth. A DN200-DN400 high-density polyethylene water permeable pipe is arranged in the well, and a 400g / m² filament geotextile is wrapped outside to enhance the filtration capacity.

[0010] According to the technical scheme, the S1 is suitable for old reservoir areas where the original impermeable system of the tailings reservoir fails or no impermeable facilities are arranged, and is suitable for complex geological environments with thin overburden, shallow roof depth, mainly strong weathered to moderately weathered rock, and difficult grouting.

[0011] According to the technical scheme, the plum blossom arrangement mode of the curtain grouting in the S2 is to insert a third row of grouting holes between two adjacent rows of grouting holes, so that each hole forms a triangular hole arrangement structure on the plane, and any three adjacent holes form an equilateral arrangement.

[0012] According to the technical scheme, the curtain grouting process in S2 adopts a bottom-up segmented grouting process, each segment has a grouting height of 1.5-2.5 meters, the grouting pressure is increased segment by segment, the initial pressure is 0.2 MPa, the maximum is not more than 0.8 MPa, and 48 hours of segment sealing and grout stabilization are required after each segment grouting is completed.

[0013] According to the technical scheme, the overlapping area in S3 adopts a process sequence of first constructing curtain grouting and then constructing the anti-seepage wall, and after the curtain grouting is formed, the lower end of the anti-seepage wall is embedded in the curtain body to form an overlapping area with a vertical direction overlap of not less than 1.5 meters and a horizontal overlap of not less than 0.3 meters.

[0014] According to the technical scheme, S3 combines an online water level monitoring and groundwater level control system, by arranging osmometers and submersible pumps on both sides of the curtain, when the groundwater level outside the curtain is higher than the set safety water level, the water pumping device is automatically started to implement dynamic pumping to form a continuous water head difference, to maintain negative pressure on the inside of the curtain, reduce the pressure of the anti-seepage wall, and block the reverse seepage of the pollution plume.

[0015] Compared with the prior art, the present application has the advantages of stronger adaptability and sealing capacity, can effectively cope with challenges such as uneven geological structure, complex hydraulic conditions and uncontrollable pollution source diffusion, introduces reinforced grouting treatment in the overlapping section, further improves the anti-seepage capacity and joint tightness, and reduces the risk of leakage caused by stress release or material aging during long-term operation of the system; By constructing a plastic concrete anti-seepage wall and arranging multiple rows of plum blossom-shaped curtain grouting bodies in the foundation, and setting an overlapping structure between them, the structural stability and anti-seepage continuity of the underground anti-seepage system are realized; In addition, the process can be linked with a negative pressure pumping system and a monitoring water level control system to form an intelligent and dynamically adjusted prevention and control system, which is suitable for various types of tailing pond pollution treatment scenarios and has significant environmental safety benefits and promotion value. BRIEF DESCRIPTION OF DRAWINGS

[0016] The accompanying drawings are included to provide a further understanding of the present application, and constitute a part of the specification, together with the embodiments of the present application, to explain the present application, and do not constitute a limitation of the present application.

[0017] In the drawings: Figure 1 is a schematic diagram of the method steps of the present application. DETAILED DESCRIPTION

[0018] The preferred embodiments of the present application are described below in conjunction with the accompanying drawings, and it should be understood that the preferred embodiments described herein are only used to illustrate and explain the present application, and do not constitute a limitation of the present application.

[0019] Example: Figure 1 As shown, the present invention provides a technical solution: a combined process of trenching for underground anti-seepage walls and grooving in a plum blossom-shaped curtain, comprising the following steps: S1. Construct a seepage-proof wall in the foundation of the area to be treated. The seepage-proof wall is set continuously along the treatment axis. The wall trench is formed by underground trenching technology, and seepage-proof material is poured in the trench to form the seepage-proof wall. S2. Curtain grouting treatment shall be carried out simultaneously or first in the lower part of the anti-seepage wall or on its upstream side. The curtain grouting adopts a multi-row sequential hole arrangement, with the grouting holes arranged in an alternating or quincunx pattern to form a continuous curtain anti-seepage layer. S3. The anti-seepage wall and the curtain grouting body have overlapping areas in the vertical or horizontal directions to form an integrated anti-seepage structure.

[0020] According to the above technical solution, the S1 seepage-proof wall material includes plastic concrete or a low-permeability seepage-proof material that can adapt to foundation deformation. Curtain grouting uses cement, water glass, bentonite grout, or other injectable materials, selected according to geological conditions; The overlapping area can be equipped with additional grouting holes or a reinforcing layer to enhance the tightness of the connection and the overall seepage prevention effect.

[0021] According to the above technical solution, the plastic concrete material of the S1 seepage-proof wall comprises a mix design with a mass ratio of cement:bentonite:fine sand:water = 1:(0.5-1.0):(2.5-3.5):(1.5-2.5). The mixture is required to have a 28-day compressive strength ≥2.5MPa, an elastic modulus ≤2000MPa, and a permeability coefficient ≤1×10⁻⁶. -6 The flow rate is cm / s, and its fluidity meets the requirements of continuous pouring without segregation or bleeding during trenching construction, thus ensuring that the wall has good flexibility, integrity and long-term impermeability, and can adapt to complex geological deformation environments.

[0022] According to the above technical solution, the underground trenching technology in S1 is rotary drilling. During construction, the main hole is laid first, followed by the auxiliary hole. Then, the trenching is carried out in a staggered sequence and the continuous vertical duct pouring process is adopted to achieve effective connection between multiple trenching sections. This avoids cold joints or structural discontinuities in the wall, thereby ensuring that the overall wall structure is uniform, continuous, and has stable seepage prevention.

[0023] According to the above technical solution, during the construction process, S1 constructs a combined wall and curtain anti-seepage system in the downstream direction of the pollution plume based on the site's hydrogeological conditions and pollutant migration path, and conducts induced extraction by setting up dedicated groundwater extraction wells or leachate drainage wells to achieve hydraulic blockage of the pollution plume and the formation of a reverse concentration gradient. The spacing between extraction wells is determined based on the formation permeability coefficient and the migration rate of contaminants, with a recommended spacing of 10 to 20 meters. The well depth is adjusted to 10 to 30 meters depending on the depth of the contaminant layer. DN200-DN400 high-density polyethylene (HDPE) permeable pipes are installed inside the wells and wrapped with 400g / m² long-filament geotextile to enhance the reverse filtration capacity. The extraction system is equipped with a programmable logic controller (PLC) automatic control system, which can receive water level and water quality data from each monitoring point in real time. It uses algorithm models to determine changes in hydraulic gradient and pollution migration trends, and dynamically adjusts the start-stop frequency and discharge of each pump to ensure that a stable head difference of higher outside and lower inside is maintained throughout the entire curtain wall structure area, thereby improving the effectiveness and adaptability of the anti-seepage system. In addition, the linkage design between the extraction system and the wall structure can provide redundant protection in the event of damage or partial failure of the wall, significantly improving the long-term safe and stable operation of the tailings dam.

[0024] According to the above technical solution, S1 is suitable for old tailings storage areas where the original anti-seepage system has failed or no anti-seepage facilities have been installed. It is especially suitable for complex geological environments with thin overburden, shallow roof depth, strata mainly composed of strongly weathered to moderately weathered rocks, and easy grouting or difficult compaction grouting. Through the wall curtain synergy of this process, effective sealing of groundwater pollution and control of seepage path can be achieved without disturbing the overlying tailings body.

[0025] According to the above technical solution, the plum blossom arrangement method adopted for curtain grouting in S2 is to intersperse a third row of grouting holes between two adjacent rows of grouting holes, so that each hole position forms a triangular hole arrangement on the plane, and any three adjacent holes form an equilateral arrangement, thereby achieving full overlap and cross-density of the grouting coverage area, improving the connectivity and integrity of the overall curtain body, and effectively reducing the probability of the existence of grouting blank areas.

[0026] According to the above technical solution, the curtain grouting process in S2 adopts a bottom-up segmented grouting process. The grouting height of each segment is 1.5-2.5 meters, and the grouting pressure increases segment by segment. The initial pressure is 0.2 MPa, and the maximum pressure does not exceed 0.8 MPa. After each segment is grouted, it is necessary to seal and stabilize the grout for 48 hours to ensure that the grout is fully diffused and solidified in the pores, forming a continuous and dense anti-seepage curtain, which improves the ability to block the migration of pollutants in weathered rock and weak bedrock strata.

[0027] According to the above technical solution, in the S3 overlapping area, the construction process adopts the sequence of first constructing the curtain grouting and then constructing the anti-seepage wall. After the curtain grouting is formed, the lower end of the anti-seepage wall is embedded in the curtain body to form an overlapping area with a vertical overlap of not less than 1.5 meters and a horizontal overlap of not less than 0.3 meters. At the same time, a row of reinforcing grouting holes is set upstream and downstream of the overlapping section for re-grouting treatment of the overlapping joint. The grouting material can be cement-based controllable gel grout, ensuring that the grout fully fills the joint gap between the two structures and fuses with the original grouting body to form an integral, closed, and continuous anti-seepage barrier. Through this construction reinforcement of the overlapping section, not only is the risk of structural cracking or leakage caused by settlement, stress concentration, or differential deformation of different anti-seepage materials effectively avoided, but the compactness, stability, and impact and seismic resistance of the entire wall curtain system under long-term service conditions are further improved.

[0028] According to the above technical solution, S3 combines online water level monitoring and groundwater level control system. By deploying piezometers and submersible pumps on both sides of the curtain, the pumping device is automatically started when the groundwater level outside the curtain is detected to be higher than the set safe water level, so as to implement dynamic extraction, thereby forming a continuous head difference, realizing the maintenance of negative pressure inside the curtain, pressure reduction of the seepage barrier wall, and reverse seepage blockage of the pollution plume, thereby improving the groundwater pollution control capability and the intelligent operation level of the system.

[0029] According to the above technical solution, the connection process between the anti-seepage wall sections is carried out by using joint pipes to ensure continuity. Specifically, this includes pre-installing steel joint pipes at the ends of adjacent sections. The joint pipes are not less than 0.8 meters long and have circumferential openings in their walls to allow the concrete of the later-poured section to bond with the previous section to form a high-bonding connection. During construction, a main hole, secondary hole, and trenching sequence construction mode is adopted. The main hole section is constructed first, and a joint pipe is pre-embedded at one end. After the secondary hole is constructed and the joint is connected, the remaining "partition wall" part between the main and secondary holes is removed manually or mechanically. Finally, the entire continuous wall is poured. When pouring concrete, the straight-lift tremie pipe method is used and the process is completed in a mud environment. The bottom of the tremie pipe is always kept at least 2 meters below the concrete surface to prevent segregation and slurry inrush. In addition, to further improve the stability of the wall quality, a quality observation hole should be left after every 6 to 8 meters of pouring for subsequent core sampling and testing. Construction quality control should be carried out in combination with process parameters such as mud specific gravity, slurry output, and pouring time during construction to ensure that the wall thickness, verticality, and density meet the design and seepage prevention performance requirements. The combination of this structural design and construction technology not only improves the continuity and reliability of the wall structure, but also significantly reduces the risk of local leakage caused by loose joints, thereby enhancing the long-term service safety of the overall waterproofing system.

[0030] Finally, it should be noted that the above descriptions are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A combined process of trenching for underground anti-seepage walls and quincunx-shaped curtain grouting in tailings dams, characterized in that: Includes the following steps: S1. Construct a seepage-proof wall in the foundation of the area to be treated. The seepage-proof wall is set continuously along the treatment axis. The wall trench is formed by underground trenching technology, and seepage-proof material is poured in the trench to form the seepage-proof wall. S2. Curtain grouting treatment shall be carried out simultaneously or first in the lower part of the anti-seepage wall or on its upstream side. The curtain grouting adopts a multi-row sequential hole arrangement, with the grouting holes arranged in an alternating or quincunx pattern to form a continuous curtain anti-seepage layer. S3. The anti-seepage wall and the curtain grouting body have overlapping areas in the vertical or horizontal directions to form an integrated anti-seepage structure.

2. The combined process of trenching and quincunx-shaped curtain grouting for underground anti-seepage walls in tailings dams according to claim 1, characterized in that, S1 seepage-proof wall materials include plastic concrete or low-permeability seepage-proof materials that can adapt to foundation deformation; The curtain grouting uses cement, water glass, bentonite grout, or other injectable materials, selected according to geological conditions; The overlapping area may be provided with additional grouting holes or a reinforcing layer.

3. The combined process of trenching and quincunx-shaped curtain grouting for underground anti-seepage walls in tailings dams according to claim 1, characterized in that, The plastic concrete material for the S1 seepage-proof wall comprises a mix design with a mass ratio of cement:bentonite:fine sand:water = 1:(0.5-1.0):(2.5-3.5):(1.5-2.5). The mixture is required to have a 28-day compressive strength ≥2.5MPa, an elastic modulus ≤2000MPa, and a permeability coefficient ≤1×10⁻⁶. -6 cm / s.

4. The combined process of trenching and quincunx-shaped curtain grouting for underground anti-seepage walls in tailings dams according to claim 1, characterized in that, The underground trenching technology in S1 is rotary drilling. During construction, the main hole is laid out first, followed by the auxiliary hole. Then, the trenching is carried out in a staggered sequence and the continuous vertical guide pipe casting process is adopted to achieve effective connection between multiple trenching sections.

5. The combined process of trenching and quincunx-shaped curtain grouting for underground anti-seepage walls in tailings dams according to claim 1, characterized in that, During the construction process, S1 constructs a combined wall and curtain anti-seepage system in the downstream direction of the pollution plume according to the site's hydrogeological conditions and pollutant migration path, and conducts induced extraction by setting up dedicated groundwater extraction wells or leachate drainage wells. The spacing between extraction wells is determined based on the formation permeability coefficient and the migration rate of contaminants. The recommended spacing is 10 to 20 meters, and the well depth is adjusted to 10 to 30 meters depending on the depth of the contaminant layer. The well is equipped with DN200-DN400 high-density polyethylene permeable pipes, and wrapped with 400g / m² long-filament geotextile to enhance the reverse filtration capacity.

6. The combined process of trenching and quincunx-shaped curtain grouting for underground anti-seepage walls in tailings dams according to claim 1, characterized in that, The S1 is applicable to old tailings storage areas where the original anti-seepage system has failed or no anti-seepage facilities have been installed. It is suitable for complex geological environments with thin overburden, shallow roof depth, strata mainly composed of strongly weathered to moderately weathered rocks, and easy grouting or difficult compaction grouting.

7. The combined process of trenching and quincunx-shaped curtain grouting for underground anti-seepage walls in tailings dams according to claim 1, characterized in that, The curtain grouting in S2 adopts a plum blossom-shaped arrangement, in which a third row of grouting holes is interspersed between two adjacent rows of grouting holes, so that each hole position forms a triangular hole arrangement on the plane, and any three adjacent holes position form an equilateral arrangement.

8. The combined process of trenching and quincunx-shaped curtain grouting for underground anti-seepage walls in tailings dams according to claim 1, characterized in that, In the S2 curtain grouting process, a bottom-up segmented grouting process is adopted. The grouting height of each segment is 1.5-2.5 meters. The grouting pressure increases segment by segment, with an initial pressure of 0.2 MPa and a maximum of 0.8 MPa. After each segment is grouted, it is necessary to seal and stabilize the grout for 48 hours.

9. The combined process of trenching and quincunx-shaped curtain grouting for underground anti-seepage walls in tailings dams according to claim 1, characterized in that, In the S3 overlapping area, the construction process adopts the sequence of first constructing the curtain grouting and then constructing the anti-seepage wall. After the curtain grouting is formed, the lower end of the anti-seepage wall is embedded in the curtain body to form an overlapping area with a vertical overlap of not less than 1.5 meters and a horizontal overlap of not less than 0.3 meters.

10. The combined process of trenching and quincunx-shaped curtain grouting for underground anti-seepage walls in tailings dams according to claim 1, characterized in that, The S3 system combines online water level monitoring and groundwater level control. By installing piezometers and submersible pumps on both sides of the curtain, the pumping device is automatically activated when the groundwater level outside the curtain is detected to be higher than the set safe water level. This dynamic extraction is used to form a continuous head difference, thereby maintaining negative pressure inside the curtain, reducing pressure on the anti-seepage wall, and blocking the reverse seepage of the pollutant plume.

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