Construction method of plastic concrete seepage interception wall for embankment grouting solid foundation in riprap rescue section

Abstract

The invention provides a construction method of an embankment grouting solid foundation plastic concrete seepage-stopping wall at a riprap rescue section. The construction method comprises the following steps: S1, arranging and positioning grouting holes; s2, grouting hole drilling; s3, proportioning the grouting slurry of the flow-state solidified soil; preparation of slurry and preparation of slurry-state solidified soil grouting liquid; s4, grouting fluid solidified soil grouting liquid is poured into the grouting pipe; and S5, the plastic concrete seepage interception wall is constructed. The method solves the problem that when the plastic concrete seepage interception wall is constructed, due to the fact that a flood prevention and emergency rescue riprap system is buried behind a watershed opening of a dike, mud loss is generated due to the fact that many holes exist in the dike polder, and hole collapse of the inner wall of the seepage interception wall is likely to be caused.

Description

Technical Field

[0001] This invention belongs to the field of cutoff wall construction, and in particular relates to a construction method for a grouting and solidification plastic concrete cutoff wall for embankment sections requiring riprap reinforcement. Background Technology

[0002] With my country's continuous efforts to optimize the layout and construction of flood storage and detention areas, and through measures such as the construction of large and medium-sized sluice gates, the capacity of these areas to cope with basin-wide floods has been significantly enhanced. This has achieved the goals of "diverting floodwaters effectively, storing them efficiently, draining them effectively, and ensuring public safety," thereby effectively protecting flood control in key areas, large and medium-sized cities, and important transportation routes, enhancing river channel flood discharge capacity, controlling the extent of flooding, and minimizing flood damage. In the construction of water conservancy projects in river basins, challenges such as limited working space, complex geological conditions, and abundant groundwater are frequently encountered. This is especially true when excavating deep foundation pits, where issues such as unfavorable soil layers and high water levels requiring attention to seepage are crucial. Cut-off walls, as a key seepage-proof structure within diaphragm walls, are widely used in various water conservancy projects, playing a vital role in cutting off groundwater seepage, reducing seepage flow, and ensuring the stability and safety of the foundation pit.

[0003] In practical engineering projects, such as those located in areas with deep backfill layers, riprap distribution, or complex geological conditions, the construction area often presents unfavorable geological conditions such as abundant boulders and well-developed pores. These strata have a high content of boulders, a wide distribution, great depth, and a loose structure, resulting in poor mud slurry wall protection during traditional cutoff wall construction. The slurry easily leaks along the pores, leading to a series of technical challenges such as trench collapse and difficulty in wall formation. To ensure the smooth construction of the cutoff wall and the seepage prevention effect of the foundation pit, pretreatment measures are often required, such as filling and solidifying the loose strata through grouting reinforcement technology. This improves the integrity, impermeability, and bearing capacity of the foundation, creating favorable conditions for subsequent cutoff wall construction. Summary of the Invention

[0004] In view of this, the present invention aims to propose a construction method for grouting and solidifying plastic concrete cutoff walls in embankments for emergency flood control and waterlogging. This method solves the problem that during the construction of plastic concrete cutoff walls, the grouting system used for flood control and waterlogging after the embankment flood outlet creates numerous pores within the embankment, leading to mud loss and potential collapse of the inner wall of the cutoff wall. By using a sequential and denser method, i.e., first constructing pilot holes, and then sequentially filling the grouting holes at intervals with pressureless filling grout, the injected fluid solidified soil grout hardens and binds the surrounding soil in the pores of the crushed stone layer, forming a denser solidified body. This improves the compressive strength and impermeability of the soil layer, achieving the purpose of filling, reinforcement, and water stoppage, thereby enhancing the bearing capacity of the foundation and completing the construction of the plastic concrete cutoff wall.

[0005] To achieve the above objectives, the technical solution of the present invention is implemented as follows:

[0006] The construction method of grouting and solidifying plastic concrete cutoff wall for riprap-filled emergency dike sections includes the following steps:

[0007] S1. Grouting hole layout and positioning: Based on the foundation grouting treatment area determined by the central axis of the cutoff wall, three rows of grouting holes are set along the axis of the cutoff wall;

[0008] S2. Grouting hole drilling: After the drilling rig is in place, drilling is carried out at a spacing of 3m between longitudinal and transverse sections. The drilling error is controlled within ±5cm. The drilling depth is controlled by drilling 1m deeper after penetrating the broken stone layer.

[0009] S3. Grouting slurry ratio for fluidized solidified soil; preparation of mud slurry and preparation of fluidized solidified soil grout;

[0010] S4. Grouting pipe for fluidized solidified soil grouting; adopt pressureless filling grouting method, grouting from the outside to the inside in a row according to the principle of sequential densification, grouting pipe down to the bottom of the hole, grouting the whole hole section, following the principle of multiple re-grouting and intermittent replenishment, until the designed injection volume is reached or grout comes out of the hole, to ensure that the grout fully fills the pores;

[0011] S5. Construction of plastic concrete cutoff wall: On the grouting and reinforced foundation, a construction platform is built, and trenches are excavated in sections. The trenches are formed by combining hydraulic grab buckets with drilling rigs. After cleaning the sediment at the bottom of the trench, plastic concrete is poured in. The trench sections are connected by cutting the ends of the pre-poured concrete to form a reliable joint, thus forming a continuous and complete cutoff wall.

[0012] Furthermore, in step S1, the first row of grouting holes is 5.5m away from the cutoff wall, the second row of grouting holes is 2m away from the cutoff wall, and the third row of grouting holes is 9.5m away from the cutoff wall. The spacing between the grouting holes is 3 meters, the hole depth is 15.70 to 20.00 meters, and the grouting depth is 12.60m to 19.00m. A total of 72 grouting holes are arranged, and grouting is carried out by drilling holes using a geological drilling rig.

[0013] Furthermore, in step S2, the hole depth is controlled between 15.70 and 20.00 meters, the borehole diameter is 70 mm, and the verticality of the grouting hole is guaranteed to be within 1%.

[0014] Furthermore, in step S3;

[0015] Mud slurry: Using a ZJ800 type vertical high-speed cyclone mixer, cohesive soil and water are mixed at a ratio of 5:4 to prepare a mud slurry with a specific gravity controlled at 1.26 g / cm³. 3 ;

[0016] For fluidized solidified soil grouting, water is added first, followed by the curing agent, cement, and slag powder. The mixture is thoroughly stirred to achieve a water-cement ratio of 1.0, and the stirring time should be no less than 3 minutes. Finally, the curing agent mixture is added to the mud, and the mixer is restarted for thorough mixing. The final mud density of the prepared fluidized solidified soil grout is 1.55 g / cm³. 3 ;

[0017] The amount of grout to be injected depends on the porosity of the crushed stone layer, calculated based on an average porosity of 20%. The calculation formula is as follows:

[0018] V=αβπr 2 ln / m;

[0019] In the formula: V: grouting volume per meter;

[0020] l: Length of injection hole;

[0021] r: Effective diffusion radius of the slurry;

[0022] n: Average fracture ratio of rock mass or porosity of soil;

[0023] α: Grout filling coefficient;

[0024] β: Slurry loss coefficient;

[0025] m: Grout stone formation rate.

[0026] Furthermore, in step S4, after the drilling depth reaches the designed depth and passes the acceptance test, a grouting pipe is lowered into the grouting hole until it is inserted into the grouting hole for about 2m. Then, the other end of the grouting pipe is connected to the mud pump of the grout storage tank. Pressureless filling grouting is used, with the grout being thinner first and then thicker, and the grouting is carried out in sequence according to the three-stage holes. The grouting sequence is from the outer grouting hole to the inner grouting hole, and the sequence number is from the two sides to the inside. Bottom grouting is used for full hole grouting.

[0027] The amount of grout injected into each grouting hole is controlled by reaching the design volume. When the design volume is reached and grout appears to be seeping out of the hole, grouting is stopped. After gravity filling and penetration into the gaps between the broken stones, the grout in the hole will settle and a second grouting will be carried out. If grout leakage or runoff occurs during the grouting process, the amount of grout injected each time is limited, and intermittent and repeated grouting is adopted until the design requirements are met.

[0028] Furthermore, step S5 specifically includes the following steps:

[0029] S51. First, according to the axial direction of the guide groove, the groove is divided into sections using joint pipes, and the trenching method is carried out in conjunction with hydraulic grab buckets and rotary drilling rigs.

[0030] S52. After the entire trench section is excavated to the design bottom elevation, the hole is swept. This is done by shoveling from one end to the other in an orderly manner, moving 50cm each time, and keeping the excavation depth at the same design elevation. The wall surface is cleaned and the sediment at the bottom of the trench is removed to eliminate the impact of the sediment at the bottom of the trench on the wall settlement. Then, a guide pipe is installed to pour plastic concrete.

[0031] S53. When moving to the next trench section for construction, use a hydraulic grab bucket to cut off 30cm from both ends of the previously poured plastic concrete section. Repeat the above excavation method until the entire plastic concrete cutoff wall is completed.

[0032] Compared with existing technologies, the construction method of grouting and solidifying plastic concrete cutoff wall for riprap emergency dike sections described in this invention has the following advantages:

[0033] (1) The method for constructing a grouting and solidification plastic concrete cutoff wall for embankment reinforcement in the riprap emergency section described in this invention addresses the issue that the riprap used for flood control and emergency reinforcement of the embankment creates numerous pores, causing the mud slurry in the holes to leak out along the pores during cutoff wall construction without mud slurry wall protection. By sequentially and densely filling and grouting the grouting holes without pressure, a fluidized solidified soil slurry is injected into the crushed stone layer, which hardens and binds the surrounding soil to form a denser solidified body. This improves the compressive strength and impermeability of the soil layer, achieving the purpose of filling, reinforcement, and water stoppage, and enhancing the bearing capacity of the foundation.

[0034] (2) The construction method of grouting and solidifying plastic concrete cutoff wall for riprap emergency dikes described in this invention uses pressureless filling grouting to inject fluid solidified soil slurry into the gaps of the crushed stone layer to solidify and stop water, ensuring the mud wall solidification effect during hole drilling, effectively preventing hole collapse, improving trench quality, reducing concrete filling coefficient, and saving project costs.

[0035] (3) The construction method of grouting and solidifying plastic concrete cutoff wall for riprap emergency dikes described in this invention combines the leakage state of the pores of the crushed stone layer on site, and mixes cement, reinforcing agent, mud and other materials in proportion to prepare fluid solidified soil grouting liquid. It can achieve rapid solidification within a specified time, solve the problem of mud leakage in the pump station foundation treatment and cutoff wall, and efficiently complete the construction of plastic concrete cutoff wall. Attached Figure Description

[0036] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings:

[0037] Figure 1 This is a schematic diagram of the construction method of grouting and solidifying plastic concrete cutoff wall for embankment reinforcement in the rock-filling emergency section according to an embodiment of the present invention;

[0038] Figure 2This is a schematic diagram showing the arrangement of grouting holes according to an embodiment of the present invention;

[0039] Figure 3 This is a schematic diagram of the preparation process of the fluidized solidified soil grouting slurry according to an embodiment of the present invention;

[0040] Figure 4 This is a schematic diagram of the drilling and grooving sequence according to an embodiment of the present invention. Detailed Implementation

[0041] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other.

[0042] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicating orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined with "first," "second," etc., may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0043] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art will understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0044] The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0045] The newly constructed Huayang River Pumping Station, part of the main construction project of the Huayang River flood storage and detention area, is located on the inner side of the Tongma Dike. The pumping station's axis is parallel to the centerline of the old Huayang Sluice Gate. The design drainage flow is 130 m³ / h. 3 / s, but because the riprap used for flood control and emergency repairs at the Huayang River pumping station embankment was buried after the floodwaters overflowed, combined with geological surveys, the riprap content was approximately 75% to 85%, with a wide distribution range, found both inside and outside the Tongma embankment, with a maximum burial depth of 18.1m and a minimum elevation of -6.5m. Numerous pores were observed within the embankment. The bottom elevation of the plastic concrete cutoff wall in the deep foundation pit was -39.30m, the top elevation of the piles was 19.50m, and the thickness was 0.8m. During the construction of the plastic concrete cutoff wall, the mud slurry in the holes would flow along the pores. All of these defects would lead to the collapse of the inner wall of the cutoff wall without mud slurry protection. In response to the above geological conditions, the project adopted grouting foundation treatment measures. Through sequential densification, pilot holes were constructed first, followed by pressureless filling grouting of grouting holes at intervals. The injected fluid solidified soil slurry hardened and cemented the surrounding soil in the pores of the crushed stone layer, forming a denser solidified body. This improved the compressive strength and impermeability of the soil layer, achieving the purpose of filling, reinforcement, and water stoppage, thereby enhancing the bearing capacity of the foundation and completing the construction of the plastic concrete cutoff wall.

[0046] like Figures 1-4 As shown, the construction method of the grouting and foundation stabilization plastic concrete cutoff wall for the embankment in the rockfill emergency repair section includes the following steps:

[0047] S1. Grouting hole layout and positioning: Based on the foundation grouting treatment area determined by the central axis of the cutoff wall, three rows of grouting holes are set along the axis of the cutoff wall;

[0048] Preferably, in step S1, the first row of grouting holes is 5.5m away from the cutoff wall, the second row of grouting holes is 2m away from the cutoff wall, and the third row of grouting holes is 9.5m away from the cutoff wall. Figure 2 As shown in the figure, the grouting holes are arranged from bottom to top as the first row of grouting holes, the second row of grouting holes, and the third row of grouting holes;

[0049] The grouting holes are spaced 3 meters apart, with a hole depth of 15.70 to 20.00 meters and a grouting depth of 12.60 to 19.00 meters. A total of 72 grouting holes are arranged, and geological drilling rigs are used to drill the holes for grouting.

[0050] S2. Grouting Hole Drilling: After the drilling rig is in place, drilling should be carried out at intervals of 3m, according to the design depth requirements for grouting treatment. The drilling error should be controlled within ±5cm. The drilling depth should be controlled by penetrating the layer of broken rocks and then drilling down 1m further (specifically, the drill rod should change from vibration to stability when encountering the layer of broken rocks). Since the maximum burial depth of the broken rocks is 18.1m, the hole depth should be controlled between 15.70 and 20.00 meters, and the hole diameter should be 70mm. The verticality of the grouting hole should be guaranteed to be within 1%. In soil layers with complex geological conditions, the drilling speed should be adjusted at any time, and the drilling speed, hole depth, hole diameter, verticality, and progress should be recorded at all times. When the progress is slow, there may be hole collapse or the drill bit encountering hard objects. The drilling rig should maintain a low drilling speed to ensure the hole diameter and verticality of the grouting hole.

[0051] S3. Grouting slurry ratio for fluidized solidified soil; preparation of mud slurry and preparation of fluidized solidified soil grout;

[0052] The core material of fluidized solidified soil grout is the curing agent. Before construction, based on the mud condition and design requirements, mix proportion and admixture tests should be conducted to determine the amount of soil hardener and verify the curing effect in order to meet the requirements of strength, fluidity, construction period and filling.

[0053] Preferably, the mud slurry is used as a retaining slurry in the construction of cast-in-place piles. To reduce waste mud slurry transportation, the waste slurry is filtered and purified, and its specific gravity is monitored to serve as a lubricating and conditioning material for the fluidized solidified soil slurry. Using a ZJ800 type cyclone vertical high-speed mixer, the cohesive soil material is mixed with water according to the determined mixing ratio parameters to prepare a mud slurry with a specific gravity controlled at 1.26 g / cm³. 3 Store the mud slurry produced each time in a storage tank, and stir the mud frequently to maintain uniformity of parameters and avoid sedimentation or segregation;

[0054] Table 1 Mud Mix Proportion Table (kg / m³) 3 )

[0055] water clay soil 560 700

[0056] Grouting of fluidized solidified soil; the core material of fluidized solidified soil grout is the curing agent. Before construction, based on the mud conditions and design requirements, mix proportions and admixture tests should be conducted to determine the curing agent dosage and verify the curing effect to meet the requirements of strength, fluidity, construction period, and filling. The fluidized solidified soil grout is prepared on-site using a vertical high-speed mixer with mix proportion parameters. When mixing the grout, water should be added first, followed by the curing agent, cement, and slag powder, and then thoroughly mixed to achieve a water-cement ratio of 1.0. The mixing time should be no less than 3 minutes. The prepared grout should have good fluidity, without segregation or sedimentation. Finally, the curing agent mixture is added to the mud, and the mixer is restarted for thorough mixing. The final mud specific gravity of the prepared fluidized solidified soil grout is 1.55 g / cm³. 3 The material is placed in a storage tank and pumped to the grouting hole using a mud pump.

[0057] Table 2. Mixing proportions of grouting solution for fluidized solidified soil (kg / m³) 3 )

[0058] Serial Number earth cement Slag powder Soil hardener water 1 700 45 90 10 700

[0059] The amount of grout to be injected into each grouting hole should be determined based on the porosity of the crushed stone layer. For now, assuming an average porosity of 20% for the crushed stone, the estimated grouting volume per meter is 11.30 m³. 3 Left and right; the calculation formula is:

[0060] V=αβπr 2 ln / m=0.8×1.25×3.14×3 2 ×1×0.2 / 0.5=11.30m 3 ;

[0061] Where: (Substitute the actual values ​​used in this construction)

[0062] V: Grouting volume per meter (m) 3 );

[0063] l: Length of injection hole (m);

[0064] r: Effective diffusion radius of slurry (m), taken as 3m;

[0065] n: Average rock mass fracture ratio or soil porosity, with soil porosity taken as 0.20;

[0066] α: Grout filling coefficient, generally taken as 0.8 to 0.9, taken as 0.8;

[0067] β: Slurry loss coefficient, 1.2 to 1.50 for rock and soil, 1.15 to 1.30 for soil, and 1.25 is selected;

[0068] m: Grout stone setting rate, taken as 0.5 to 0.95, with a smaller value when the water-cement ratio is high and a larger value when the water-cement ratio is low, taken as 0.5m.

[0069] S4. Grouting of fluidized solidified soil using grouting pipes: After the borehole reaches the designed depth and passes inspection, grouting pipes are lowered into the grouting hole until they are inserted about 2m into the hole. The other end of the grouting pipe is then connected to the mud pump in the grout storage tank. Pressureless filling grouting is used, starting with thinner grout and gradually increasing the density. Grouting is carried out in sequence according to the three-stage sequence of holes. The grouting sequence proceeds from the outer grouting holes to the inner grouting holes, starting with the two sides and then the inner side. Bottom grouting is used for full-hole grouting. Each hole is grouted with the principle of grouting small amounts and repeating the process until the grout volume is less than the design requirement. The specific gravity of the grout is controlled by actual measurement. The injection of grout is usually controlled by the amount of grout injected into each grouting hole when the design amount is reached. When the design amount is reached and grout appears to be seeping out of the hole, the grouting is stopped. After gravity filling and penetration into the gaps between the broken stones, the grout in the hole will settle and a second grouting will be carried out. If grout leakage or runoff occurs during the grouting process, the amount of grout injected each time is limited and intermittent and repeated grouting is adopted until the design requirements are met.

[0070] S5. Construction of plastic concrete cutoff wall: Level the construction site and build a plastic cutoff wall construction platform.

[0071] S51. First, according to the axial direction of the guide trench, the trench is divided into sections using joint pipes, and the trenching method is carried out in combination with hydraulic grab buckets and rotary drilling rigs (i.e., the upper soil layer and the soil-pebble layer are trenched using hydraulic grab buckets, and the weakly weathered to reinforced bedrock part is trenched using rotary drilling rigs; in the upper part, the main hole is drilled using rotary drilling rigs, and the auxiliary hole is grabbed by hydraulic grab buckets).

[0072] S52. After the entire trench section is excavated to the design bottom elevation, the borehole is swept. This is done by systematically digging from one end to the other, moving 50cm at a time, and keeping the excavation depth at the same design elevation. The wall surface is cleaned and the sediment at the bottom of the trench is removed to eliminate the impact of the sediment on the wall settlement. Then, a guide pipe is installed to pour plastic concrete.

[0073] S53. Finally, in order to improve the integrity and waterproof and seepage-resistant capacity of the underground continuous wall at the joint pipe joint and avoid the formation of a smooth arc surface at the contact surface, when moving to the next trench section for construction, a hydraulic grab bucket is used to cut off 30cm of the two ends of the plastic concrete poured in the previous section. The above excavation method is repeated until the entire plastic concrete cutoff wall is completed.

[0074] Example:

[0075] Specific Implementation: The dike at Huayanghe Pumping Station, due to flooding and subsequent flood control efforts involving the placement of riprap, contained a large amount of loose stones distributed over a wide area, resulting in internal seepage pores. During the construction of the plastic concrete cutoff wall, a large amount of mud slurry in the trenches was lost through these pores, leaving the cutoff wall without mud slurry protection. To improve the bearing capacity of the foundation, three rows of grouting holes were installed along the axis of the cutoff wall on the Tongma Dike. Grouting was carried out using drilling rigs, with the outer rows being drilled first and then the inner rows being drilled sequentially. Specifically, pilot holes were constructed first, followed by grouting holes drilled at 3-meter intervals. Following the grout mix ratio determined by the on-site process testing laboratory, cement, soil hardener, slag powder, and other materials were first mixed with water and thoroughly stirred in a high-speed vertical mixer before adding materials of appropriate density. The mud is thoroughly mixed to prepare a fluidized solidified soil grouting solution, which is then injected into the pores of the riprap foundation using a pressureless filling grouting method. This hardens and binds the surrounding soil, forming a denser solidified body, thereby improving the compressive strength and impermeability of the soil layer to achieve the purpose of filling, reinforcement, and water stoppage. Finally, using a hydraulic grab bucket and rotary drilling method for trenching, the joint pipe is used to divide the trench into sections along the axis of the guide trench. Mud slurry is used to systematically excavate from one end to the other at the same design elevation, and the wall surface and bottom sediment are cleaned. Plastic concrete is then poured for the entire trench section. When moving to the next section, a 30cm section is cut off at the joint using a hydraulic grab bucket to improve the integrity and waterproofing / seepage resistance of the cutoff wall, until the entire construction of the plastic concrete cutoff wall is efficiently completed.

[0076] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. 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 method for constructing a grouting-supported plastic concrete cutoff wall for riprap-filled emergency dike sections, characterized by: Includes the following steps: S1. Grouting hole layout and positioning: Based on the foundation grouting treatment area determined by the central axis of the cutoff wall, three rows of grouting holes are set along the axis of the cutoff wall; S2. Grouting hole drilling: After the drilling rig is in place, drilling is carried out at a spacing of 3m between longitudinal and transverse sections. The drilling error is controlled within ±5cm. The drilling depth is controlled by drilling 1m deeper after penetrating the broken stone layer. S3. Grouting slurry ratio for fluidized solidified soil; preparation of mud slurry and preparation of fluidized solidified soil grout; S4. Grouting pipe for fluidized solidified soil grouting; adopt pressureless filling grouting method, grouting from the outside to the inside in a row according to the principle of sequential densification, grouting pipe down to the bottom of the hole, grouting the whole hole section, following the principle of multiple re-grouting and intermittent replenishment, until the designed injection volume is reached or grout comes out of the hole, to ensure that the grout fully fills the pores; S5. Construction of plastic concrete cutoff wall: On the grouting and reinforced foundation, a construction platform is built, and trenches are excavated in sections. The trenches are formed by combining hydraulic grab buckets with drilling rigs. After cleaning the sediment at the bottom of the trench, plastic concrete is poured in. The trench sections are connected by cutting the ends of the pre-poured concrete to form a reliable joint, thus forming a continuous and complete cutoff wall.

2. The construction method of the grouting and foundation-consolidation plastic concrete cutoff wall for the riprap emergency dike section according to claim 1, characterized in that: In step S1, the first row of grouting holes is 5.5m away from the cutoff wall, the second row of grouting holes is 2m away from the cutoff wall, and the third row of grouting holes is 9.5m away from the cutoff wall. The spacing between the grouting holes is 3 meters, the hole depth is 15.70 to 20.00 meters, and the grouting depth is 12.60m to 19.00m. A total of 72 grouting holes are arranged, and grouting is carried out by drilling holes using a geological drilling rig.

3. The construction method of the grouting and foundation-consolidation plastic concrete cutoff wall for the riprap emergency dike section according to claim 1, characterized in that: In step S2, the hole depth is controlled between 15.70 and 20.00 meters, the borehole diameter is 70 mm, and the verticality of the grouting hole is guaranteed to be within 1%.

4. The construction method of the grouting and foundation-consolidation plastic concrete cutoff wall for the riprap emergency dike section according to claim 1, characterized in that: In step S3; Mud slurry: Using a ZJ800 type vertical high-speed cyclone mixer, cohesive soil and water are mixed at a ratio of 5:4 to prepare a mud slurry with a specific gravity controlled at 1.26 g / cm³. 3 ; For fluidized solidified soil grouting, water is added first, followed by the curing agent, cement, and slag powder. The mixture is thoroughly stirred to achieve a water-cement ratio of 1.0, and the stirring time should be no less than 3 minutes. Finally, the curing agent mixture is added to the mud, and the mixer is restarted for thorough mixing. The final mud density of the prepared fluidized solidified soil grout is 1.55 g / cm³. 3 ; The amount of grout to be injected depends on the porosity of the crushed stone layer, calculated based on an average porosity of 20%. The calculation formula is as follows: V=αβπr 2 ln / m; In the formula: V: grouting volume per meter; l: Length of injection hole; r: Effective diffusion radius of the slurry; n: Average fracture ratio of rock mass or porosity of soil; α: Grout filling coefficient; β: Slurry loss coefficient; m: Grout stone formation rate.

5. The construction method of the grouting and foundation-consolidation plastic concrete cutoff wall for the riprap emergency dike section according to claim 1, characterized in that: In step S4, after the drilling depth reaches the designed depth and passes the acceptance test, a grouting pipe is lowered into the grouting hole until it is inserted into the grouting hole for about 2m. Then, the other end of the grouting pipe is connected to the mud pump in the grout storage tank. Pressureless filling grouting is used, with the grout being thinner first and then thicker. Grouting is carried out in sequence and density according to the three-stage holes. The grouting sequence is from the outer grouting hole to the inner grouting hole, and the sequence number is from the two sides to the inside. Bottom grouting is used for full hole grouting. The amount of grout injected into each grouting hole is controlled by reaching the design volume. When the design volume is reached and grout appears to be seeping out of the hole, grouting is stopped. After gravity filling and penetration into the gaps between the broken stones, the grout in the hole will settle and a second grouting will be carried out. If grout leakage or runoff occurs during the grouting process, the amount of grout injected each time is limited, and intermittent and repeated grouting is adopted until the design requirements are met.

6. The construction method of the grouting and foundation-consolidation plastic concrete cutoff wall for the riprap emergency dike section according to claim 1, characterized in that: In step S5, specifically Includes the following steps: S51. First, according to the axial direction of the guide groove, the groove is divided into sections using joint pipes, and the trenching method is carried out in conjunction with hydraulic grab buckets and rotary drilling rigs. S52. After the entire trench section is excavated to the design bottom elevation, the hole is swept. This is done by shoveling from one end to the other in an orderly manner, moving 50cm each time, and keeping the excavation depth at the same design elevation. The wall surface is cleaned and the sediment at the bottom of the trench is removed to eliminate the impact of the sediment at the bottom of the trench on the wall settlement. Then, a guide pipe is installed to pour plastic concrete. S53. When moving to the next trench section for construction, use a hydraulic grab bucket to cut off 30cm from both ends of the previously poured plastic concrete section. Repeat the above excavation method until the entire plastic concrete cutoff wall is completed.

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