A tailings pond underground diaphragm wall trenching and plum blossom shaped curtain grouting synergistic process

Abstract

The application discloses a tailing pond underground anti-seepage wall trenching and plum-blossom-shaped curtain grouting synergic process, and relates to the technical field of grouting synergy, and comprises the following steps: S1, constructing an anti-seepage wall body in the foundation of the region to be treated, the anti-seepage wall body is continuously arranged along the treatment axis, the underground trenching technology is used to form a wall body groove section, and the anti-seepage material is poured in the groove to form the anti-seepage wall, S2, simultaneously or in advance, the curtain grouting treatment is implemented in the lower region of the anti-seepage wall body or the upstream side thereof, the curtain grouting adopts a multi-row and sequenced hole arrangement mode, the grouting holes are arranged in a staggered or plum-blossom-shaped mode, and a continuous curtain anti-seepage layer is formed, S3, the anti-seepage wall and the curtain grouting body are provided with a lap joint region in the vertical direction or the horizontal direction, and a wall-curtain integrated anti-seepage structure is formed, the application realizes the unity of the structural stability and the anti-seepage continuity of the underground anti-seepage system by constructing the plastic concrete anti-seepage wall in the foundation and arranging the multi-row plum-blossom-shaped curtain grouting body, and further arranging the lap joint structure between the two.

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 combined 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 joint of the wall body. 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 body 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 bottom and downstream area of the tailing pond and achieve effective blocking of 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 combined 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 combined process, comprising the following steps:

[0006] 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 diaphragm material is poured in the slot to form a diaphragm wall;

[0007] S2, simultaneously or in advance, implementing curtain grouting treatment in the lower area 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;

[0008] S3, the impervious wall and the curtain grouting body are provided with overlapping areas in the vertical direction or the horizontal direction, forming an impervious structure integrated with the wall and the curtain.

[0009] According to the above technical solution, the S1 impervious wall material includes plastic concrete or low-permeability, adaptable foundation deformation impervious material.

[0010] The curtain grouting uses cement, water glass, bentonite slurry or other grouting materials, which are selected according to geological conditions.

[0011] The overlapping area can be provided with a reinforced grouting hole or a reinforced layer.

[0012] According to the above technical solution, the plastic concrete material of the S1 impervious wall includes 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 a 28-day compressive strength ≥ 2.5 MPa, an elastic modulus ≤ 2000 MPa, and a permeability coefficient ≤ 1 × 10 -6 cm / s.

[0013] According to the above technical solution, the underground slotting technology in S1 is a rotary drilling method, which realizes effective connection between multiple slotting sections by first laying a main hole, then laying a secondary hole, and then using interval sequence slotting and continuous straight guide pipe pouring process.

[0014] According to the above technical solution, the S1 constructs a wall-curtain combined impervious system in the downstream direction of the pollution plume during construction according to the site hydrogeological conditions and the pollution migration path, and induces extraction through the layout of special underground water extraction wells or leachate drainage wells to realize hydraulic blockage of the pollution plume and formation of a reverse concentration gradient.

[0015] Among them, the extraction well spacing is laid according to the formation 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;

[0016] DN200-DN400 high-density polyethylene water permeable pipes are arranged in the well, and 400g / m² filament geotextile is wrapped outside to enhance the filtration capacity.

[0017] According to the above technical solution, the S1 is suitable for old reservoir areas where the original impervious system of the tailings reservoir has failed or no impervious facilities have been set up, and is suitable for complex geological environments with thin overburden, shallow roof depth, mainly strong to medium weathered rock, easy to bubble or difficult to compact grouting.

[0018] According to the technical scheme, the plum blossom-shaped arrangement mode used in the curtain grouting in S2 is that a third row of grouting holes is arranged between two adjacent rows of grouting holes, so that each hole position forms a triangular hole arrangement structure on a plane, and any three adjacent hole positions form an equilateral arrangement.

[0019] According to the technical scheme, a self-down-to-up segmented grouting process is used in the curtain grouting in S2, each segment of grouting height is 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 grouting stabilization are required after each segment of grouting is completed.

[0020] According to the technical scheme, the overlapping area in S3 is constructed by using the process sequence of first constructing the 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.

[0021] According to the technical scheme, S3 combines an online water level monitoring and underground water level control system, by arranging osmometers and submersible pumps on both sides of the curtain, when the underground water 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, so as 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.

[0022] Compared with the prior art, the beneficial effects of the present application are: the present application has 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 compactness, and reduces the risk of leakage caused by stress release or material aging in long-term operation of the system;

[0023] 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 the two, the structural stability and anti-seepage continuity of the underground anti-seepage system are realized.

[0024] 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 scenes and has significant environmental safety benefits and promotion value. BRIEF DESCRIPTION OF DRAWINGS

[0025] The accompanying drawings are included to provide a further understanding of the present application, and constitute a part of the specification, illustrate the present application together with the embodiments, and do not constitute a limitation on the present application.

[0026] In the drawings:

[0027] Figure 1 is a schematic diagram of the method steps of the present application. DETAILED DESCRIPTION

[0028] The preferred embodiments of the present application are described below in conjunction with the accompanying drawings, it should be understood that the preferred embodiments described here are only used to illustrate and explain the present application, and are not used to limit the present application.

[0029] Embodiment: As shown in the present application provides a technical solution, a tailings pond underground cutoff wall trenching and plum blossom-shaped curtain grouting synergistic process, comprising the following steps: Figure 1

[0030] S1, build a cutoff wall in the foundation of the area to be treated, the cutoff wall is continuously arranged along the treatment axis, the wall slot section is formed by using underground trenching technology, and the cutoff wall is formed by pouring impermeable material in the slot;

[0031] S2, simultaneously or in advance, implement curtain grouting treatment in the lower part of the cutoff wall 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 impermeable layer is formed;

[0032] S3, the cutoff wall and the curtain grouting body are provided with an overlapping area in the vertical direction or the horizontal direction, forming a wall-curtain integrated impermeable structure.

[0033] According to the above technical solution, the material of the cutoff wall in S1 includes plastic concrete or low-permeability impermeable material that can adapt to foundation deformation;

[0034] The curtain grouting adopts cement, water glass, bentonite slurry or other grouting materials, which are selected according to the geological conditions;

[0035] The overlapping area can be provided with grouting holes or a reinforced layer to enhance the connection density and overall impermeability effect.

[0036] According to the above technical solution, the plastic concrete material of the cutoff wall in S1 includes 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), the mixture requires 28-day compressive strength ≥ 2.5 MPa, elastic modulus ≤ 2000 MPa, and permeability coefficient ≤ 1 × 10 -6 cm / s, and its fluidity meets the requirements of continuous pouring without segregation and bleeding in trenching construction, so as to ensure that the wall has good deformation, integrity and long-term impermeability, and is suitable for complex geological deformation environment.

[0037] ​According to the technical scheme, the underground trenching technology in S1 is a rotary drilling method, and the effective connection between multiple trenching sections is realized by first laying a main hole, then laying a secondary hole, and then using interval and sequence trenching and continuous straight guide pipe pouring process, so that the cold joint or discontinuous structure in the wall is avoided, and the uniformity, continuity and seepage stability of the overall structure of the wall are ensured.

[0038] According to the technical scheme, S1 constructs a wall curtain combined seepage prevention system in the downstream direction of the pollution plume during construction according to the hydrogeological conditions and the pollution migration path of the site, and induces extraction through the laying of special groundwater extraction wells or leachate drainage wells to realize hydraulic blockage of the pollution plume and formation of a reverse concentration gradient.

[0039] The extraction well spacing is laid according to the formation 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 (HDPE) water permeable pipe is arranged in the well, and a 400g / m² filament geotextile is wrapped outside to enhance the filtration capacity.

[0040] 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, judge the hydraulic gradient change and pollution migration trend through an algorithm model, and dynamically adjust the start-stop frequency and displacement of each water pump to ensure that a stable water head difference of high outside and low inside is maintained in the entire curtain wall structure area, thereby improving the effectiveness and adaptability of the seepage prevention system.

[0041] In addition, the linkage design of the extraction system and the wall curtain structure can provide redundant protection in the case of curtain damage or local failure, significantly improving the security and stability of the long-term operation of the tailings pond.

[0042] According to the technical scheme, S1 is suitable for old tailings ponds that have failed original seepage prevention systems or have not set up seepage prevention facilities, and is especially suitable for complex geological environments with thin overburden, shallow roof depth, mainly weathered to moderately weathered rock, easy to spew or difficult to compress grouting. Through the synergistic effect of the wall curtain, effective sealing and seepage path control of groundwater pollution can be achieved without disturbing the overlying accumulated tailings body.

[0043] According to the technical scheme, the quincunx arrangement in S2 is to insert a third row of grouting holes between two adjacent rows of grouting holes, so that the hole positions form a triangular hole arrangement structure in the plane, and any three adjacent hole positions form an equilateral arrangement, thereby realizing full overlap and cross compaction 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.

[0044] According to the technical scheme, in S2, a segmented grouting process from bottom to top is adopted in the curtain grouting process, each grouting height is 1.5-2.5 meters, the grouting pressure is increased gradually, the initial pressure is 0.2 MPa, the maximum is not more than 0.8 MPa, and after each grouting is completed, the segment needs to be sealed and grouted for 48 hours to ensure that the grout fully diffuses and consolidates in the pore to form a continuous and dense anti-seepage curtain body, and the ability to block the migration of pollutants in the weathered rock and weak bedrock stratum is improved.

[0045] According to the technical scheme, in S3, the lap joint area is constructed by adopting the process sequence of first constructing the 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 lap joint of not less than 1.5 meters and a horizontal lap joint of not less than 0.3 meters, and a row of reinforcing grouting holes is arranged upstream and downstream of the overlapping area for re-grouting treatment of the lap joint, and the grouting material can be selected from a cement-based controllable gel slurry to ensure that the grout fully fills the joint gap between the two structures and is integrated with the original grouting body to form an overall closed and continuous anti-seepage blocking zone. Through the construction of the overlapping section, not only the risk of structural cracking or leakage caused by settlement, stress concentration or differential deformation of different anti-seepage materials is effectively avoided, but also the compactness, stability and impact resistance and shock resistance of the entire wall curtain system under long-term service conditions are further improved.

[0046] According to the technical scheme, S3 combines an online water level monitoring and underground water level control system, which is arranged with osmometers and submersible pumps on both sides of the curtain. When the underground water 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, realize negative pressure maintenance inside the curtain, pressure reduction of the anti-seepage wall and reverse seepage blocking of the pollution plume, and improve the underground water pollution control ability and the intelligent level of system operation.

[0047] According to the technical scheme, the joint pipe connection process is adopted between the anti-seepage wall groove sections to ensure continuity, which specifically includes that a steel joint pipe is pre-set at the end of the adjacent groove section, the length of the joint pipe is not less than 0.8 meters, a circumferential opening structure is provided on the pipe wall to allow the combination of the post-poured groove section concrete and the previous section to form a high-bonding-force connection; during construction, a main hole, a secondary hole and a grooving sequence construction mode are adopted, the main hole groove section is constructed first, the joint pipe is pre-buried at one end thereof, then after the secondary hole is constructed and connected to the joint, the residual "partition wall" part between the main hole and the secondary hole is removed by manual or mechanical means, and finally the continuous wall body is formed by overall pouring, the pouring of concrete is completed in a slurry environment by using a vertical guide pipe method, and the bottom end of the guide pipe is always kept below the concrete liquid surface by not less than 2 meters to prevent segregation and grout gushing;

[0048] In addition, in order to further improve the quality stability of the wall, a quality observation hole is left for later core detection after every 6-8 meters of pouring, and the construction quality is controlled in combination with the mud specific gravity, slurry output, pouring time and other process parameters in the construction process, so that the wall thickness, perpendicularity and compactness meet the design and anti-seepage performance requirements.

[0049] The combination of the structural design and the construction process not only improves the continuity and reliability of the wall structure, but also significantly reduces the local leakage risk caused by the non-compactness of the joint, and enhances the long-term service safety of the overall anti-seepage system.

[0050] Finally, it should be noted that: the above only for the preferred examples of the present application, and not for limiting the present application, although the present application is described in detail with reference to the foregoing examples, for those skilled in the art, it still can be modified to the technical solutions recorded in the foregoing embodiments, or equivalent replacement of part of the technical features. Any modification, equivalent replacement, improvement, etc. within the spirit and principles of the present application shall be included in the protection scope of the present application.

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 an impermeable wall in the foundation of the area to be treated. The impermeable wall is continuously set along the treatment axis, and the wall trenches are formed using underground trenching technology. Impermeable materials are poured into the trenches to form the impermeable wall. The impermeable wall material includes plastic concrete. The plastic concrete material of the impermeable wall includes a mix system 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; S2. Curtain grouting treatment is first implemented in the lower area of ​​the anti-seepage wall. Curtain grouting adopts a multi-row sequential hole arrangement. The grouting holes are arranged in a quincunx pattern to form a continuous curtain anti-seepage layer. The quincunx arrangement of the curtain grouting 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. During the curtain grouting process, a segmented grouting process from bottom to top 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. S3. The anti-seepage wall and the curtain grouting body have overlapping areas in the vertical or horizontal direction to form an integrated anti-seepage structure. During construction, the overlapping area adopts the process 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. The overlapping area is provided with encrypted grouting holes or a reinforcing layer; 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, with a spacing of 10 to 20 meters. The well depth is adjusted to 10 to 30 meters depending on the depth of the contaminated layer.

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, The curtain grouting uses cement, water glass, and bentonite grout as grouting materials, selected according to geological conditions.

3. The combined process of trenching for underground anti-seepage walls and quincunx-shaped curtain grouting 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.

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 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.

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, 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.

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 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.

Images