Grooving construction method of underground concrete diaphragm wall and diaphragm wall

Abstract

The invention relates to a grooving construction method of an underground concrete anti-seepage wall and the anti-seepage wall, and the grooving construction method of the underground concrete anti-seepage wall comprises the following steps: drilling a plurality of main holes to a preset depth in sequence, and filling bentonite slurry; auxiliary holes formed between every two adjacent main holes are sequentially drilled for the first time, the first-time drilling depth of the auxiliary holes is at most one half of the preset depth, and the auxiliary holes are filled with bentonite slurry; removing a wall body between the main hole and the auxiliary hole; the multiple auxiliary holes are sequentially drilled to the preset depth for the second time, and bentonite slurry is filled; and wall bodies between the main holes and the auxiliary holes are removed, and concrete groove sections are formed. According to the method, the multiple main holes are sequentially drilled firstly, and then the multiple auxiliary holes are drilled again, so that the grooving stability is guaranteed, meanwhile, the length of a single concrete groove section in each construction period can be increased, the number of joints between the groove sections is reduced, and the integrity and the anti-seepage performance of the anti-seepage wall are improved.

Description

Technical Field

[0001] The present invention relates to the technical field of cutoff walls, and particularly to a trench construction method for an underground concrete cutoff wall and a cutoff wall. Background Art

[0002] With the rapid development of modern construction technologies and construction techniques, the construction technology of underground concrete cutoff walls has developed rapidly. As a primary anti-seepage structure, the concrete cutoff wall has been widely used in engineering due to its advantages such as high strength, reliable anti-seepage performance, and good structural integrity.

[0003] Currently, affected by the project scale, terrain, and geological conditions, the underground concrete cutoff wall needs to be constructed in stages. The length of the sectional unit trench is generally 4 - 6m, and the maximum depth is generally within 60m. Under the condition of thick overburden, the depth of the concrete cutoff wall may exceed 60m. How to maintain the stability of the hole wall is the key problem in the trench formation of the concrete cutoff wall and also the technical difficulty restricting the progress of the construction of high-depth cutoff walls.

[0004] In China, tens of thousands of cutoff wall projects with conventional depths have been built, but the number of cutoff wall projects with a depth exceeding 60m is very few. The increase in the depth of the cutoff wall greatly increases the construction difficulty, quality problems of each process, and the possibility of defects or even accidents. Summary of the Invention

[0005] Based on this, it is necessary to provide a trench construction method for an underground concrete cutoff wall and a cutoff wall in view of the technical problems in the existing construction technology of cutoff walls, such as limited length of the construction unit trench, limited depth, and easy hole collapse.

[0006] A trench construction method for an underground concrete cutoff wall, the trench construction method for the underground concrete cutoff wall includes the following steps:

[0007] Drill a plurality of main holes in sequence to a preset depth, and fill bentonite mud;

[0008] Drill the secondary holes arranged between two adjacent main holes for the first time, the maximum depth of the first drilling of the secondary holes is at most half of the preset depth, and fill bentonite mud in the secondary holes;

[0009] Remove the wall body between the main hole and the secondary hole;

[0010] Drill a plurality of the secondary holes in sequence to the preset depth, and fill bentonite mud;

[0011] Remove the wall body between the main hole and the secondary hole to form a concrete trench section.

[0012] In one embodiment, the step of sequentially drilling a plurality of main holes to a preset depth and filling bentonite mud includes:

[0013] Using a percussion drill to drill the main holes, and injecting the bentonite mud into the gap between the hole wall of the main hole and the drill pipe.

[0014] In one embodiment, the injection depth of the bentonite mud is kept consistent with the real-time drilling depth of the main hole.

[0015] In one embodiment, the step of removing the wall body between the main hole and the auxiliary hole includes:

[0016] Using a grab bucket to remove the wall body between the main hole and the auxiliary hole, forming a cavity with a depth not exceeding half of the preset depth, and the cavity is filled with bentonite mud.

[0017] In one embodiment, the step of sequentially drilling the auxiliary hole arranged between two adjacent main holes for the first time, the first drilling depth of the auxiliary hole is at most half of the preset depth, and filling bentonite mud into the auxiliary hole includes:

[0018] Controlling the inclination rate of the auxiliary hole within 0.06%.

[0019] In one embodiment, the diameter D1 of the main hole and the diameter D2 of the auxiliary hole satisfy the conditions:

[0020] 0.9m ≤ D1 ≤ 1.1m, 0.9m ≤ D2 ≤ 1.1m.

[0021] In one embodiment, the thickness W of the wall body formed between the main hole and the auxiliary hole satisfies the conditions:

[0022] 0.35m ≤ W ≤ 0.45m.

[0023] In one embodiment, the length L of a section of the concrete trough section satisfies the conditions:

[0024] 5.9m ≤ L ≤ 7.7m.

[0025] In one embodiment, the concrete trough section includes a head end and a tail end. When constructing the concrete trough section adjacent to the formed concrete trough section, the formed concrete trough section is defined as the first trough section, and the concrete trough section adjacent to the first trough section is defined as the second trough section. After completing the first trough section, the construction of the second trough section includes:

[0026] Using the main hole corresponding to the end of the first groove section as the starting main hole of the second groove section, drill the multiple main holes on the second groove section in sequence, and fill bentonite slurry.

[0027] An impervious wall is constructed by using the grooving construction method of the underground concrete impervious wall as described above.

[0028] Advantages of the present invention:

[0029] The present invention protects a grooving construction method for an underground concrete impervious wall. By drilling multiple main holes to a preset depth in sequence and filling bentonite slurry, it is possible to prevent the main holes formed by drilling from collapsing. By drilling the secondary holes between two adjacent main holes for the first time in sequence and controlling the drilling depth within one-half of the preset depth of the main hole, the risk of collapse during construction can be effectively reduced, thereby improving the stability during construction. Similarly, during the first drilling of the secondary holes, filling bentonite slurry in the secondary holes in a timely manner is also to prevent collapse during the drilling process. After drilling the secondary holes, remove the wall body between the main holes and the secondary holes to form a cavity with a depth not greater than one-half of the preset depth. Then drill the multiple secondary holes to the preset depth for the second time in sequence, and finally remove the wall body between the main holes and the secondary holes to form a concrete groove section. The concrete groove section is used to fill concrete to form an impervious wall. In the present application, by drilling and removing the multiple main holes, secondary holes, and the wall body between the main holes and the secondary holes in steps, the shape and size of the finally formed concrete groove section can be better controlled, which is beneficial to ensuring the construction accuracy and quality, thus meeting the setting requirements. By drilling the secondary holes first by one-half and then the remaining one-half, it is beneficial to prevent collapse during construction, so that this method can be applied to impervious walls with a depth greater than 60m. By first drilling multiple main holes in sequence and then drilling multiple secondary holes at one time, while ensuring the stability of grooving, the length of a single concrete groove section within each construction period can be increased, the number of joints between the groove sections can be reduced, construction materials and costs can be saved, the integrity and impervious performance of the impervious wall can be improved, the potential economic losses caused by the leakage risk can be reduced, the grooving efficiency can be improved, the construction period can be shortened, and the equipment rental and labor costs can be reduced. Description of the drawings

[0030] Figure 1 It is a schematic diagram of the positions of the main holes and secondary holes provided by an embodiment of the present invention.

[0031] Figure 2 It is a schematic diagram after drilling the main holes in the grooving construction method of the underground concrete impervious wall provided by an embodiment of the present invention.

[0032] Figure 3Schematic diagram after the first drilling of the secondary hole in the trench construction method of the underground concrete cut-off wall provided by an embodiment of the present invention.

[0033] Figure 4 Schematic diagram after removing the wall body between the primary hole and the secondary hole in the trench construction method of the underground concrete cut-off wall provided by an embodiment of the present invention.

[0034] Figure 5 Schematic diagram after the second drilling of the secondary hole in the trench construction method of the underground concrete cut-off wall provided by an embodiment of the present invention.

[0035] Figure 6 Schematic diagram after forming the concrete trench segment in the trench construction method of the underground concrete cut-off wall provided by an embodiment of the present invention.

[0036] Figure 7 Flow chart of the trench construction method of the underground concrete cut-off wall provided by an embodiment of the present invention.

[0037] Reference numerals:

[0038] 100, primary hole; 200, secondary hole; 300, wall body; 400, cavity; 500, concrete trench segment. Detailed implementation manners

[0039] In order to make the above objects, features and advantages of the present invention more obvious and understandable, the following will describe the detailed implementation manners of the present invention with reference to the accompanying drawings. Many specific details are set forth in the following description in order to fully understand the present invention. However, the present invention can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without departing from the connotation of the present invention. Therefore, the present invention is not limited by the specific embodiments disclosed below.

[0040] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present invention.

[0041] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include at least one such feature. In the description of the present invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise specifically defined.

[0042] In the present invention, unless otherwise clearly specified and defined, terms such as "installed", "connected", "joined", "fixed", etc. should be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or integrated; it may be a mechanical connection or an electrical connection; it may be directly connected or indirectly connected through an intermediate medium, and it may be the communication inside two elements or the interaction relationship between two elements, unless otherwise clearly defined. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0043] In the present invention, unless otherwise clearly specified and defined, the first feature being "on" or "under" the second feature may be that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, the first feature being "above", "over" and "on top of" the second feature may be that the first feature is directly above or obliquely above the second feature, or merely indicates that the horizontal height of the first feature is higher than that of the second feature. The first feature being "under", "beneath" and "underneath" the second feature may be that the first feature is directly below or obliquely below the second feature, or merely indicates that the horizontal height of the first feature is less than that of the second feature.

[0044] It should be noted that when an element is referred to as "fixed to" or "disposed on" another element, it may be directly on the other element or there may also be an intermediate element. When an element is considered to be "connected" to another element, it may be directly connected to the other element or there may be an intermediate element at the same time. The terms "vertical", "horizontal", "up", "down", "left", "right" and similar expressions used herein are for illustrative purposes only and do not represent the only implementation manner.

[0045] Refer to Figures 1 to 7 , an embodiment of the present invention provides a grooving construction method for an underground concrete cut-off wall. The grooving construction method for the underground concrete cut-off wall includes the following steps:

[0046] S10. Drill a plurality of main holes 100 in sequence to a preset depth and fill bentonite mud;

[0047] S20. Drill the secondary holes 200 arranged between two adjacent main holes 100 in sequence for the first time. The depth of the first drilling of the secondary holes 200 is at most one - half of the preset depth, and fill bentonite slurry into the secondary holes 200.

[0048] S30. Remove the wall body 300 between the main holes 100 and the secondary holes 200.

[0049] S40. Drill the multiple secondary holes 200 in sequence for the second time to the preset depth, and fill bentonite slurry.

[0050] S50. Remove the wall body 300 between the main holes 100 and the secondary holes 200 to form a concrete groove section 500.

[0051] This technical solution protects a construction method for forming a groove of an underground concrete impervious wall. By drilling multiple main holes 100 in sequence to the preset depth and filling bentonite slurry, it is possible to prevent the main holes 100 formed by drilling from collapsing. By drilling the secondary holes 200 arranged between two adjacent main holes 100 in sequence for the first time and controlling the drilling depth within one - half of the preset depth of the main holes 100, the risk of collapse during construction can be effectively reduced, thereby improving the stability during construction. Similarly, during the first drilling of the secondary holes 200, filling bentonite slurry into the secondary holes 200 in a timely manner is also to prevent collapse during the drilling process. After drilling the secondary holes 200, remove the wall body 300 between the main holes 100 and the secondary holes 200 to form a cavity 400 with a depth not greater than one - half of the preset depth. Then drill the multiple secondary holes 200 in sequence for the second time to the preset depth, and finally remove the wall body 300 between the main holes 100 and the secondary holes 200 to form a concrete groove section 500. The concrete groove section 500 is used to fill concrete to form an impervious wall. In this application, by drilling and removing the multiple main holes 100, secondary holes 200 and the wall body 300 between the main holes 100 and the secondary holes 200 in steps, the shape and size of the finally formed concrete groove section 500 can be better controlled, which is beneficial to ensuring the construction accuracy and quality, thus meeting the setting requirements. And by drilling the secondary holes 200 first by one - half and then the remaining one - half, it is beneficial to prevent collapse during construction, so that this method can be applied to impervious walls with a depth greater than 60m. And by first drilling multiple main holes 100 in sequence and then drilling multiple secondary holes 200 at one time, while ensuring the stability of groove formation, it is possible to increase the length of a single concrete groove section 500 within each construction period, reduce the number of joints between groove sections, save construction materials and costs, improve the integrity and impervious performance of the impervious wall, reduce the potential economic losses brought by the leakage risk, improve the groove - forming efficiency, shorten the construction period, and reduce the equipment rental and labor costs.

[0052] There is no limit to the number of primary holes 100 and secondary holes 200 in a concrete slot section 500, which can be three, four, or even more. It should be noted that the number of secondary holes 200 is 1 less than the number of primary holes 100. If the number of primary holes 100 is n, then the number of secondary holes 200 is n - 1. In this application, taking the number of primary holes 100 as 3 and the number of secondary holes 200 as 2 as an example for illustration.

[0053] In this embodiment, with reference to Figures 1 to 6 for understanding, in Figure 1 three spaced - apart primary holes 100 are arranged from left to right, represented by 1, 3, and 5 respectively. A 2nd secondary hole 200 is arranged between the 1st primary hole 100 and the 3rd primary hole 100, and a 4th secondary hole 200 is arranged between the 3rd primary hole 100 and the 5th primary hole 100. During construction, as Figure 2 shown, first use a percussion drill to drill the 1st, 3rd, and 4th primary holes 100, and then (as Figure 3 shown) drill the 2nd and 4th secondary holes 200 respectively to half of the depth of the primary holes 100. Then (as Figure 4 shown) grab and remove the wall body 300 between the primary holes 100 and the secondary holes 200 to form a cavity 400 with a depth of half of the depth of the primary holes 100. Then (as Figure 5 shown) drill the remaining 2nd and 4th secondary holes 200 again, and finally (as Figure 6 shown) grab and remove the remaining wall body 300 to form the concrete slot section 500.

[0054] It should be noted that during the process of drilling the primary holes 100, drilling the secondary holes 200 twice, and grabbing the wall body 300, bentonite mud is always filled. By the bentonite mud, a low - permeability "mud skin" is formed on the slot wall to balance the formation pressure to prevent hole collapse, and at the same time support the hole wall to keep it stable. Moreover, by filling bentonite mud, the mud can carry the cuttings generated by drilling and excavation to the mud circulation system to avoid sedimentation affecting the hole - forming quality. And the mud can reduce the friction between the drill bit and the formation and reduce the wear of the equipment.

[0055] In one of the embodiments, drilling multiple primary holes 100 to a preset depth in sequence and filling bentonite mud includes: S11. Use a percussion drill to drill the primary holes 100 and inject bentonite mud into the gap between the hole wall of the primary holes 100 and the drill pipe.

[0056] In this embodiment, it is applicable to hard strata such as sand-gravel pebbles and bedrock. Therefore, an impact drill, such as an impact drill of model CZ-22, is selected. The rock mass can be broken by impact, and the filled bentonite mud has excellent shaft protection effect and relatively high hole-forming efficiency. By injecting bentonite mud in real time into the pores between the hole wall of the main hole 100 and the drill pipe, while preventing the collapse of the main hole 100 by shaft protection, the friction between the drill pipe and the formation can be reduced, and the loss of the drill pipe can be decreased.

[0057] In one embodiment, the injection depth of the bentonite mud is kept consistent with the real-time drilling depth of the main hole 100.

[0058] When drilling the main hole 100, the injection depth of the bentonite mud is kept consistent with the real-time drilling depth of the main hole 100, so that a low-permeability "mud skin" is formed by the bentonite mud during the drilling process, continuously covering the entire hole wall to prevent local collapse or instability of the loose section of the formation. Injecting the bentonite mud in real time and synchronously can avoid the hole wall being exposed to groundwater or soil pressure due to the lag of the mud liquid level, reducing the risk of collapse. In addition, the injection depth of the mud is synchronized with the drilling depth to ensure that the drill cuttings are fully suspended and discharged through the circulation system, reducing the accumulation of sediment at the bottom of the trench and ensuring the hole-forming quality; in addition, the injection depth of the mud is synchronized with the drilling depth, so that the static pressure of the bentonite mud is dynamically matched with the formation pressure, inhibiting the infiltration of groundwater and the deformation of the soil body, and avoiding the collapse of the hole wall due to pressure imbalance. Moreover, the bentonite mud can cover the hole wall and the drill pipe throughout the process, making the lubricating effect of the bentonite on the hole wall and the drill pipe continuously effective, reducing the frictional resistance between the drill bit and the formation, and extending the service life of the equipment.

[0059] As Figure 4 shown, in one embodiment, removing the wall body 300 between the main hole 100 and the auxiliary hole 200 includes: S31. Using a grab crane to remove the wall body 300 between the main hole 100 and the auxiliary hole 200 to form a cavity 400 with a depth not exceeding half of the preset depth, and the cavity 400 is filled with bentonite mud.

[0060] It is preferred to use a hydraulic grab (such as KRC-2 type, SG35 type). The closing width of the hydraulic grab matches the thickness of the cut-off wall to ensure the breaking efficiency of the wall body 300 between the main hole 100 and the auxiliary hole 200. By first forming a cavity 400 with a depth not exceeding half of the preset depth, it is beneficial to ensure the stability during the trench forming. Filling the cavity 400 with bentonite mud is also to prevent collapse. Through the above process, while ensuring the continuity and anti-seepage performance of the cut-off wall, the construction risk can be effectively controlled, and it is applicable to easily collapsible strata such as sand-gravel pebbles and loose backfill soil.

[0061] In one embodiment, the auxiliary hole 200 disposed between two adjacent main holes 100 is drilled for the first time. The first drilling depth of the auxiliary hole 200 is at most one-half of the preset depth, and bentonite mud is filled in the auxiliary hole 200, including: S21. Control the inclination rate of the auxiliary hole 200 within 0.06%.

[0062] By controlling the inclination rate of the auxiliary hole 200 within 0.06%, the perpendicularity of the auxiliary hole 200 and the relative positional relationship between the auxiliary hole 200 and the main hole 100 are ensured to ensure the smooth removal of the wall body 300. It can be understood that when drilling the auxiliary hole 200, bentonite mud is injected while drilling.

[0063] In one embodiment, the diameter D1 of the main hole 100 and the diameter D2 of the auxiliary hole 200 satisfy the conditions 0.9m ≤ D1 ≤ 1.1m and 0.9m ≤ D2 ≤ 1.1m.

[0064] By setting the diameter D1 of the main hole 100 in the range greater than or equal to 0.9m and less than or equal to 1.1m, and setting the diameter of the auxiliary hole 200 in the range greater than or equal to 0.9m and less than or equal to 1.1m, the diameters of the main hole 100 and the auxiliary hole 200 are relatively reasonable, which is easy to drill and can ensure the stability during drilling.

[0065] In one embodiment, the diameter of the main hole 100 is 0.9m, and the diameter of the auxiliary hole 200 is also 0.9m; in another specific embodiment, the diameters of the main hole 100 and the auxiliary hole 200 are both 1m; in still some specific embodiments, the diameters of the main hole 100 and the auxiliary hole 200 are both 1.1m. In another embodiment, the diameter of the main hole 100 can also be set to 1.1m, and the diameter of the auxiliary hole 200 is 0.9m or 1m.

[0066] In one embodiment, the thickness W of the wall body 300 formed between the main hole 100 and the auxiliary hole 200 satisfies the condition: 0.35m ≤ W ≤ 0.45m. By setting the thickness W of the wall body 300 formed between the main hole 100 and the auxiliary hole 200 to be greater than or equal to 0.35m and less than or equal to 0.45m, the phenomenon of collapse during drilling of the main hole 100 and the auxiliary hole 200 is avoided, thereby ensuring the stability during drilling of the main hole 100 and the auxiliary hole 200. In one embodiment, the thickness W of the wall body 300 formed between the main hole 100 and the auxiliary hole 200 is 0.35m; in another specific embodiment, the thickness W of the wall body 300 formed between the main hole 100 and the auxiliary hole 200 is 0.4m; in still another specific embodiment, the thickness W of the wall body 300 formed between the main hole 100 and the auxiliary hole 200 is 0.45m.

[0067] In one embodiment, the length L of a concrete slot section 500 satisfies the condition: 5.9m ≤ L ≤ 7.7m. By setting the length L of a concrete slot section 500 to be greater than or equal to 5.9m and less than or equal to 7.7m, the length of a concrete slot section 500 is made longer, reducing the number of joints between the slot sections, saving joint construction materials and costs. At the same time, the integrity and anti-seepage performance of the cut-off wall are improved, the potential economic losses caused by seepage risks are reduced, the slot-forming efficiency is increased, the construction period is shortened, and the equipment rental and labor costs are reduced.

[0068] In one specific embodiment, the length L of a concrete slot section 500 is 5.9m; in another specific embodiment, the length L of a concrete slot section 500 is 6.8m; in still another specific embodiment, the length L of a concrete slot section 500 is 7.7m.

[0069] In one embodiment, the concrete slot section 500 includes a head end and a tail end. When constructing a concrete slot section 500 adjacent to the already formed concrete slot section 500, the already formed concrete slot section 500 is defined as the first slot section, and the concrete slot section 500 adjacent to the first slot section is defined as the second slot section. After completing the first slot section, the second slot section is constructed, including: using the main hole 100 corresponding to the tail end of the first slot section as the starting main hole 100 of the second slot section, and sequentially drilling multiple main holes 100 on the second slot section and filling bentonite slurry.

[0070] In this embodiment, by using the main hole 100 corresponding to the tail end of the first-phase slot section as the starting main hole 100 of the second-phase slot section, it is beneficial to reduce the number of joints between the slot sections and save joint construction materials and costs. The specific slot-forming method for the second slot section is the same as that for the first slot section and will not be elaborated here.

[0071] An embodiment of the present invention further provides a cut-off wall, which is constructed by using the above-described slot-forming construction method of the underground concrete cut-off wall.

[0072] The cut-off wall provided in this embodiment is constructed by using the above-described slot-forming construction method of the underground concrete cut-off wall. By first sequentially drilling multiple main holes 100 and then drilling multiple secondary holes 200 at one time, while ensuring the stability of slot formation, the length of a single concrete slot section 500 in each construction period can be increased, the number of joints between the slot sections is reduced, construction materials and costs are saved. At the same time, the integrity and anti-seepage performance of the cut-off wall are improved, the potential economic losses caused by seepage risks are reduced, the slot-forming efficiency is increased, the construction period is shortened, and the equipment rental and labor costs are reduced.

[0073] The technical features of the above-described embodiments can be combined arbitrarily. For the sake of brevity of description, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered as the scope described in this specification.

[0074] The above-described embodiments merely represent several implementation manners of the present invention. The description is relatively specific and detailed, but it should not be construed as a limitation on the scope of the invention patent. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several modifications and improvements can still be made, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the invention patent should be subject to the appended claims.

Claims

1. A trenching construction method for an underground concrete anti-seepage wall, characterized in that: The trenching construction method of the underground concrete anti-seepage wall comprises the following steps: Drilling multiple main holes to a preset depth in sequence and filling them with bentonite slurry; Sequentially drilling the auxiliary holes disposed between two adjacent main holes for the first time, wherein the first drilling depth of the auxiliary holes is at most one half of the preset depth, and filling the auxiliary holes with bentonite slurry; Removing the wall between the main hole and the auxiliary hole; sequentially drilling the plurality of auxiliary holes for a second time to the preset depth, and filling them with bentonite slurry; The wall between the main hole and the auxiliary hole is removed to form a concrete trough section.

2. The trenching construction method for underground concrete anti-seepage wall according to claim 1, characterized in that: The method of drilling a plurality of main holes to a preset depth in sequence and filling the holes with bentonite slurry comprises: The main hole is drilled by using an impact drill, and the bentonite slurry is injected into the gap between the hole wall of the main hole and the drill rod.

3. The trenching construction method for underground concrete anti-seepage wall according to claim 2, characterized in that: The injection depth of the bentonite slurry is consistent with the real-time drilling depth of the main hole.

4. The trenching construction method for underground concrete anti-seepage wall according to claim 1, characterized in that: The removing of the wall between the main hole and the auxiliary hole comprises: A grab machine is used to remove the wall between the main hole and the auxiliary hole to form a cavity with a depth not exceeding half of the preset depth, and the cavity is filled with bentonite slurry.

5. The trenching construction method for underground concrete anti-seepage wall according to claim 1, characterized in that: The method of sequentially drilling the auxiliary holes disposed between two adjacent main holes for the first time, wherein the first drilling depth of the auxiliary holes is at most one-half of the preset depth, and filling the auxiliary holes with bentonite slurry, comprises: The inclination rate of the auxiliary hole is controlled within 0.06%.

6. The trenching construction method for underground concrete anti-seepage wall according to claim 1, characterized in that: The diameter D1 of the main hole and the diameter D2 of the secondary hole meet the following conditions: 0.9m≤D1≤1.1m, 0.9m≤D2≤1.1m.

7. The trenching construction method for underground concrete anti-seepage wall according to claim 6, characterized in that: The thickness W of the wall formed between the main hole and the secondary hole satisfies the condition: 0.35m≤W≤0.45m.

8. The trenching construction method for underground concrete anti-seepage wall according to claim 6, characterized in that: The length L of a concrete trough section satisfies the following conditions: 5.9m≤L≤7.7m.

9. The trenching construction method for underground concrete anti-seepage wall according to any one of claims 1 to 8, characterized in that: The concrete trough section includes a head end and a tail end. When constructing the concrete trough section adjacent to the formed concrete trough section, the formed concrete trough section is defined as a first trough section, and the concrete trough section adjacent to the first trough section is defined as a second trough section. After the first trough section is completed, the second trough section is constructed, including: The main hole corresponding to the tail end of the first slot section is used as the starting main hole of the second slot section, and multiple main holes on the second slot section are drilled in sequence and filled with bentonite slurry.

10. An anti-seepage wall, characterized in that: The anti-seepage wall is constructed by using the trenching construction method for underground concrete anti-seepage wall as described in any one of claims 1-9.

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