Distributed grouting construction method for pile side of secant pile

Abstract

The invention relates to the technical field of building construction, in particular to a secant pile side distributed grouting construction method which comprises the following steps: lowering a B pile reinforcement cage fixed with a grouting head into a to-be-poured B pile pouring hole; b pile concrete is poured, the two mud jacking core pipes are connected with a mud jacking pump through mud conveying pipes correspondingly, and the two mud jacking core pipes with stop-grouting plugs are put into the bottoms of the two sets of sounding pipes correspondingly through lifting equipment; after the sounding pipe is sealed by the expansion stop-grouting plug, the grouting pump injects cement paste with the design required amount into the grouting head at the pile end of the pile B in a pressing mode, and grouting is stopped after the grouting stopping condition is achieved; the grouting stopping plug is contracted, the grouting stopping plug is lifted upwards to the position of the grouting head on the pile side adjacent to the upper portion of the grouting stopping plug, after the grouting stopping plug is expanded to seal the sounding pipe, the grouting pump injects cement paste with the design required amount to the grouting head on the pile side of the B pile in a pressing mode, and grouting is stopped after the grouting stopping condition is met; the invention provides a construction method capable of improving the bearing capacity and the non-deformability of the secant pile.

Description

Technical Field

[0001] This invention relates to the field of building construction technology, and in particular to a method for distributed grouting construction on the side of interlocking piles. Background Technology

[0002] Interlocking piles are constructed by partially interlocking circumferential sections of adjacent concrete piles, with reinforcing cages inserted into piles constructed in subsequent alternating rows to form a continuous, waterproof, and retaining structure with excellent seepage prevention capabilities. The interlocking piles are arranged with alternating rows of unreinforced plain concrete piles (Pile A) and reinforced concrete piles (Pile B). During construction, piles A are constructed first, followed by piles B, with pile B completed before the initial setting of the concrete in piles A. Both piles A and B are constructed using full-casing drilling rigs. During the drilling of pile B, the concrete at the intersection of adjacent piles A is cut away to achieve the interlocking effect.

[0003] Interlocking piles, as a type of diaphragm wall, are increasingly used in large bridge foundation projects due to their excellent water-stopping performance and high anti-collapse capability. However, interlocking piles often employ slurry wall protection during construction. The inherent drawback of slurry wall protection is the formation of sediment at the pile tip and mud cake on the pile side, which weakens their bearing capacity and deformation resistance. Furthermore, because interlocking piles are formed by the interlocking of circular A-piles and B-piles, their wall bearing capacity and deformation resistance are not as good as traditional segmented diaphragm walls. Large bridge foundations often have high requirements for the bearing capacity and deformation resistance of diaphragm walls, but currently, there is no effective way to improve the bearing capacity and deformation resistance of interlocking piles. Summary of the Invention

[0004] The purpose of this invention is to provide a method for distributed grouting construction on the side of interlocking piles, so as to solve the technical problems existing in the background art.

[0005] To achieve the above objectives, the technical solution of the present invention is as follows: A method for distributed grouting construction on the side of interlocking piles includes the following steps: Step 1: Tie the B-pile reinforcement cage of the interlocking pile, and set two grouting heads at the bottom of the front and rear sides of the B-pile reinforcement cage respectively. Set several grouting heads on the side walls of the front and rear sides of the B-pile reinforcement cage from bottom to top at the designed spacing. Use a set of sonic logging tubes to connect several grouting heads on the front side wall of the B-pile reinforcement cage and one grouting head at the bottom of the front side of the B-pile reinforcement cage. Use another set of sonic logging tubes to connect several grouting heads on the rear side wall of the B-pile reinforcement cage and one grouting head at the bottom of the rear side of the B-pile reinforcement cage. Step 2: Drill two adjacent A-pillar pouring holes at a specified depth using a casing drilling rig. Then, pour A-pillar concrete into the two adjacent A-pillar pouring holes to form two adjacent A-pillars. Step 3: Drill a B pile pouring hole to a specified depth between two adjacent A piles using a casing drilling rig, and cut off the part where the two adjacent A piles intersect with the B pile to be poured between the two A piles. Step 4: Lower the B-pillar reinforcement cage with the grouting head fixed into the B-pillar pouring hole to be poured; Step 5: Pour concrete for pile B. After the integrity of pile B is qualified by sonic logging and the concrete strength of pile B reaches 75%, connect the two grouting core tubes to the grouting pump through the grout delivery pipe. Use the lifting equipment to put the two grouting core tubes with grout stop plugs into the bottom of the two sets of sonic logging tubes. Step Six: After the expansion plug seals the sonic logging tube, the grouting pump injects the designed amount of cement grout into the grouting head at the end of pile B. Grouting is terminated when the conditions for termination are met. Step 7: Shrink the grout stop plug and lift it up to the position of the grouting head on the pile side above it. After the grout stop plug expands and seals the sonic logging tube, the grouting pump injects the designed amount of cement grout into the grouting head on the pile side of pile B. When the grouting termination conditions are met, the grouting is terminated. Step 8: Repeat step 7 until the remaining cement grout injection on the side of a single B pile is completed; Step 9: Based on the construction path of the interlocking piles, on the basis of the two A piles completed in Step 2, complete the construction of the remaining interlocking piles in the order of constructing A piles first and then B piles; when constructing each B pile, complete the distributed post-grouting construction of the interlocking piles in accordance with Steps 3 to 8.

[0006] Furthermore, the two sets of sonic logging tubes in step one are fixedly connected to the inside of the B pile reinforcement cage by means of steel bar binding or welding.

[0007] Furthermore, protective reinforcing bars for protecting the grouting head are welded to the bottom end and outer wall of the B pile reinforcement cage.

[0008] Furthermore, the number of B-piles in the reinforcement cages for binding the interlocking piles in step one corresponds to the number of B-piles in the interlocking piles to be constructed.

[0009] Furthermore, after the drilling of the B pile casting hole is completed, the hole is cleaned once, and after the B pile reinforcement cage is lowered, the hole is cleaned a second time.

[0010] Furthermore, the grout-stopping plug is model ZF-A51, and two grout-stopping plugs are installed at intervals on the lower part of each grouting core tube. A grout outlet is opened between the two grout-stopping plugs in the grouting core tube. A grout outlet is opened at the bottom end of each set of sonic logging tubes. Several grout outlets are opened on the side wall of each set of sonic logging tubes according to the design interval. A grouting head is connected to the outside of each grout outlet. When grouting is applied to the grouting head at the pile end of pile B, one grout-stopping plug at the upper part of each grouting core tube expands, while the lower grout-stopping plug does not work. When grouting is applied to the grouting head on the pile side of pile B, both grout-stopping plugs on each grouting core tube expand.

[0011] Furthermore, after the B-pillar reinforcement cage is lowered, each set of sonic logging tubes is filled with clean water to check the sealing of the connection between the sonic logging tubes and the grouting head. If leakage occurs, the leaking part is repaired by welding. The top of each set of sonic logging tubes protrudes vertically 200-500mm above the ground and is fixed by welding with positioning bars. After each set of sonic logging tubes is filled with clean water, the top opening of the sonic logging tube is sealed.

[0012] Furthermore, the grouting pressure when the grouting pump injects cement grout into the grouting head at the end of pile B is 0.8~4.0 MPa; the grouting pressure when the grouting pump injects cement grout into the grouting head on the side of pile B is 0.2~2.0 MPa.

[0013] Furthermore, the design requirements for the grouting volume of each grouting end face of a single B pile must meet the calculation formula for pile end grouting volume: ; The design requirement for the grouting volume at each grouting end face of a single B pile must meet the calculation formula for pile side grouting volume: ; The design requirements for the grouting volume of a single B pile must meet the calculation formula for the grouting volume of a single pile: ; In the formula: This represents the empirical coefficient for the grouting volume on the side of pile B; This represents the empirical coefficient for the grouting amount at the pile tip of pile B; Indicates the number of grouting end faces on the side of pile B; Indicates the diameter of pile B; This indicates the grouting volume of a single B pile; This indicates the amount of grout applied to each grouting face at the tip of a single B-pile. This indicates the amount of grouting applied to each grouting end face on the side of a single B-pile.

[0014] Furthermore, the grouting termination condition is as follows: Condition 1: The grouting volume meets the design requirements, and the average grouting pressure in the last 5 minutes reaches the grouting termination pressure. Condition 2: If the grouting volume has reached the design requirements and the average grouting pressure in the last 5 minutes is not less than 0.8 times the grouting termination pressure, the grouting volume for this layer should be increased to 110% of the design value. Condition 3: If the grouting volume has reached the design requirements and the average grouting pressure in the last 5 minutes is less than 0.8 times the grouting termination pressure, the grouting volume for this layer should be increased to 120% of the design value. Condition 4: The grouting volume is greater than 80% of the design value, and the average grouting pressure in the last 5 minutes is greater than 1.2 times the grouting termination pressure.

[0015] Compared with the prior art, the beneficial effects of the present invention are: 1. This invention, during the construction of interlocking pile B-piles, after the sonic testing of the pile body integrity is qualified and the concrete strength of the pile body reaches 75%, uses a grouting pump to inject cement grout at a certain pressure into the pile end soil layer and the pile side soil layer respectively through the pile end and pile side soil layer. Through the penetration, filling, compaction, splitting and consolidation of cement grout, the strength of the pile end soil and pile side soil is enhanced, the sediment is reinforced, the mud skin is eliminated, and thus the bearing capacity and deformation resistance of the interlocking pile are improved.

[0016] 2. This invention enables discrete distribution of grouting points, achieving multi-point grouting with small spacing. Compared to traditional ring pipe grouting, it offers greater controllability and more uniform distribution. This invention allows for the use of different grouting reinforcement materials and different grouting parameters within the same sonic logging pipe, based on geological structural characteristics. The grout stopper in this invention can move freely within the sonic logging pipe, allowing for continuous grouting reinforcement within the grouting reinforcement area as needed. This invention achieves combined grouting by connecting grouting heads in series with sonic logging pipes, reducing the number of joints in the rebar cage connection and effectively improving construction efficiency. Attached Figure Description

[0017] Figure 1 This is a construction flowchart of the present invention; Figure 2 This is a schematic diagram of the distributed post-grouting construction equipment involved in this invention; Figure 3 This is a schematic diagram of the structure of the stop plug and its connecting components in this invention. Detailed Implementation

[0018] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments.

[0019] See Figures 1-3 As shown, a method for distributed grouting construction on the side of interlocking piles includes the following steps: Step 1: Tie the B-pile reinforcement cage of the interlocking pile, and set two grouting heads at the bottom of the front and rear sides of the B-pile reinforcement cage respectively. Set several grouting heads on the side walls of the front and rear sides of the B-pile reinforcement cage from bottom to top at the designed spacing. Use a set of sonic logging tubes to connect several grouting heads on the front side wall of the B-pile reinforcement cage and one grouting head at the bottom of the front side of the B-pile reinforcement cage. Use another set of sonic logging tubes to connect several grouting heads on the rear side wall of the B-pile reinforcement cage and one grouting head at the bottom of the rear side of the B-pile reinforcement cage. Step 2: Drill two adjacent A-pillar pouring holes at a specified depth using a casing drilling rig. Then, pour A-pillar concrete into the two adjacent A-pillar pouring holes to form two adjacent A-pillars. Step 3: Drill a B pile pouring hole to a specified depth between two adjacent A piles using a casing drilling rig, and cut off the part where the two adjacent A piles intersect with the B pile to be poured between the two A piles. Step 4: Lower the B-pile reinforcement cage with the grouting head fixed into the B-pile pouring hole; the bottom of one of the grouting heads at the bottom end of the B-pile reinforcement cage should exceed the pile end elevation of the B-pile and enter the bearing layer by 5cm.

[0020] Step 5: Pour concrete for pile B. After the integrity of pile B is qualified by sonic logging and the concrete strength of pile B reaches 75%, connect the two grouting core tubes to the grouting pump through the grout delivery pipe. Use the lifting equipment to put the two grouting core tubes with grout stop plugs into the bottom of the two sets of sonic logging tubes. Step Six: After the expansion plug seals the sonic logging tube, the grouting pump injects the designed amount of cement grout into the grouting head at the end of pile B. Grouting is terminated when the conditions for termination are met. Step 7: Shrink the grout stop plug and lift it up to the position of the grouting head on the pile side above it. After the grout stop plug expands and seals the sonic logging tube, the grouting pump injects the designed amount of cement grout into the grouting head on the pile side of pile B. When the grouting termination conditions are met, the grouting is terminated. Step 8: Repeat step 7 until the remaining cement grout injection on the side of a single B pile is completed; Step 9: Based on the construction path of the interlocking piles, on the basis of the two A piles completed in Step 2, complete the construction of the remaining interlocking piles in the order of constructing A piles first and then B piles; when constructing each B pile, complete the distributed post-grouting construction of the interlocking piles in accordance with Steps 3 to 8.

[0021] In this embodiment, the two sets of sonic logging tubes in step one are fixedly connected to the inside of the B pile reinforcement cage by means of steel bar binding or welding.

[0022] In this embodiment, protective reinforcing bars for protecting the grouting head are welded to the bottom end and the outer wall of the B pile reinforcement cage.

[0023] In this embodiment, the number of B-piles in the interlocking piles tied in step one corresponds to the number of B-piles in the interlocking piles to be constructed.

[0024] In this embodiment, the hole is cleaned once after the B pile is drilled and a second cleaning is performed after the B pile reinforcement cage is lowered.

[0025] In this embodiment, the grout stopper is model ZF-A51, and two grout stoppers are installed at intervals on the lower part of each grouting core tube. A grout outlet is opened between the two grout stoppers on the grouting core tube. A grout outlet is opened at the bottom end of each set of sonic logging tubes. Several grout outlets are opened on the side wall of each set of sonic logging tubes according to the design interval. A grouting head is connected to the outside of each grout outlet. When grouting to the grouting head at the pile end of B pile, one grout stopper at the upper part of each grouting core tube expands, and one grout stopper at the lower part does not work. When grouting to the grouting head on the pile side of B pile, both grout stoppers on each grouting core tube expand.

[0026] In this embodiment, after the B-pillar reinforcement cage is lowered, each set of sonic logging pipes is filled with clean water to check the sealing of the connection between the sonic logging pipes and the grouting head. If leakage occurs, the leaking part is repaired by welding to ensure the sealing of the grouting pipeline. The top of each set of sonic logging pipes protrudes vertically 200-500mm above the ground and is fixed by welding with positioning ribs. After each set of sonic logging pipes is filled with clean water, the top opening of the sonic logging pipe is sealed to prevent debris from entering and causing blockage.

[0027] In this embodiment, the grouting pressure when the grouting pump injects cement grout into the grouting head at the end of pile B is 0.8~4.0 MPa; the grouting pressure when the grouting pump injects cement grout into the grouting head at the side of pile B is 0.2~2.0 MPa.

[0028] The design requirement for the grouting volume at each grouting end face of a single B-pile must meet the calculation formula for pile end grouting volume: ; The design requirement for the grouting volume at each grouting end face of a single B pile must meet the calculation formula for pile side grouting volume: ; The design requirements for the grouting volume of a single B pile must meet the calculation formula for the grouting volume of a single pile: ; In the formula: This represents the empirical coefficient for the grouting volume on the side of pile B; This represents the empirical coefficient for the grouting amount at the pile tip of pile B; Indicates the number of grouting end faces on the side of pile B; Indicates the diameter of pile B; This indicates the grouting volume of a single B pile; This indicates the amount of grout applied to each grouting face at the tip of a single B-pile. This indicates the amount of grouting applied to each grouting end face on the side of a single B-pile.

[0029] The grouting termination condition is: Condition 1: The grouting volume meets the design requirements, and the average grouting pressure in the last 5 minutes reaches the grouting termination pressure. Condition 2: If the grouting volume has reached the design requirements and the average grouting pressure in the last 5 minutes is not less than 0.8 times the grouting termination pressure, the grouting volume for this layer should be increased to 110% of the design value. Condition 3: If the grouting volume has reached the design requirements and the average grouting pressure in the last 5 minutes is less than 0.8 times the grouting termination pressure, the grouting volume for this layer should be increased to 120% of the design value. Condition 4: The grouting volume is greater than 80% of the design value, and the average grouting pressure in the last 5 minutes is greater than 1.2 times the grouting termination pressure.

[0030] It should be noted that: the lifting equipment in this invention is model WT-20; the sonic logging pipe in this invention also serves as a grouting pipe; the cement grout used for grouting is ordinary Portland cement with a strength grade of not less than 42.5 MPa; the water-cement ratio of the cement grout is controlled between 0.5 and 0.7, preferably lower, and the initial setting time is not less than 2 to 3 hours (which can be determined through testing). Adjustments can be made appropriately during the initial stage of grouting or intermittent grouting; a water-reducing agent can be added to the low water-cement ratio grout, and the dosage should be determined through testing; the cement grout should be thoroughly stirred for at least 2 minutes; the grout must be filtered twice through a 10-mesh screen when entering the storage tank to prevent impurities from clogging the grouting holes and pipes. The prepared grout should have good fluidity, without segregation or sedimentation.

[0031] In the description of this invention, it should be noted that the terms "upper", "lower", "left", "right", "inner", "outer", "top / bottom", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this 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. Therefore, they should not be construed as limiting this invention.

[0032] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Any simple modifications, equivalent substitutions, and improvements made by those skilled in the art to the above embodiments without departing from the scope of the technical solution of the present invention, based on the technical essence of the present invention, shall still fall within the protection scope of the technical solution of the present invention.

Claims

1. A method for distributed grouting construction on the side of interlocking piles, characterized in that, Includes the following steps: Step 1: Tie the B-pile reinforcement cage of the interlocking pile, and set two grouting heads at the bottom of the front and rear sides of the B-pile reinforcement cage respectively. Set several grouting heads on the side walls of the front and rear sides of the B-pile reinforcement cage from bottom to top at the designed spacing. Use a set of sonic logging tubes to connect several grouting heads on the front side wall of the B-pile reinforcement cage and one grouting head at the bottom of the front side of the B-pile reinforcement cage. Use another set of sonic logging tubes to connect several grouting heads on the rear side wall of the B-pile reinforcement cage and one grouting head at the bottom of the rear side of the B-pile reinforcement cage. Step 2: Drill two adjacent A-pillar pouring holes at a specified depth using a casing drilling rig. Then, pour A-pillar concrete into the two adjacent A-pillar pouring holes to form two adjacent A-pillars. Step 3: Drill a B pile pouring hole to a specified depth between two adjacent A piles using a casing drilling rig, and cut off the part where the two adjacent A piles intersect with the B pile to be poured between the two A piles. Step 4: Lower the B-pillar reinforcement cage with the grouting head fixed into the B-pillar pouring hole to be poured; Step 5: Pour concrete for pile B. After the integrity of pile B is qualified by sonic logging and the concrete strength of pile B reaches 75%, connect the two grouting core tubes to the grouting pump through the grout delivery pipe. Use the lifting equipment to put the two grouting core tubes with grout stop plugs into the bottom of the two sets of sonic logging tubes. Step Six: After the expansion plug seals the sonic logging tube, the grouting pump injects the designed amount of cement grout into the grouting head at the end of pile B. Grouting is terminated when the conditions for termination are met. Step 7: Shrink the grout stop plug and lift it up to the position of the grouting head on the pile side above it. After the grout stop plug expands and seals the sonic logging tube, the grouting pump injects the designed amount of cement grout into the grouting head on the pile side of pile B. When the grouting termination conditions are met, the grouting is terminated. Step 8: Repeat step 7 until the remaining cement grout injection on the side of a single B pile is completed; Step 9: Based on the construction path of the interlocking piles, on the basis of the two A piles completed in Step 2, complete the construction of the remaining interlocking piles in the order of constructing A piles first and then B piles; when constructing each B pile, complete the distributed post-grouting construction of the interlocking piles in accordance with Steps 3 to 8.

2. The method for distributed grouting construction of interlocking piles according to claim 1, characterized in that: In step one, the two sets of sonic logging tubes are fixedly connected to the inside of the B pile reinforcement cage by means of steel bar binding or welding.

3. The method for distributed grouting construction of interlocking piles according to claim 1, characterized in that: The bottom end and outer wall of the B pile reinforcement cage are respectively welded with protective steel bars to protect the grouting head.

4. The method for distributed grouting construction of interlocking piles according to claim 1, characterized in that: The number of B-piles in the reinforcement cage for binding the interlocking piles in step one corresponds to the number of B-piles in the interlocking piles to be constructed.

5. The method for distributed grouting construction of interlocking piles according to claim 1, characterized in that: After the B pile casting hole is drilled, it is cleaned once, and after the B pile reinforcement cage is lowered, it is cleaned a second time.

6. The method for distributed grouting construction of interlocking piles according to claim 1, characterized in that: The grout stopper is model ZF-A51, and two grout stoppers are installed at intervals on the lower part of each grouting core tube. A grout outlet is opened between the two grout stoppers on the grouting core tube. A grout outlet is opened at the bottom end of each set of sonic logging tubes. Several grout outlets are opened on the side wall of each set of sonic logging tubes according to the design interval. A grouting head is connected to the outside of each grout outlet. When grouting to the grouting head at the pile end of B pile, one grout stopper at the upper part of each grouting core tube expands, and one grout stopper at the lower part does not work. When grouting to the grouting head on the pile side of B pile, both grout stoppers on each grouting core tube expand.

7. The method for distributed grouting construction of interlocking piles according to claim 1, characterized in that: After the B-pillar reinforcement cage is lowered, fill each set of sonic logging tubes with clean water and check the sealing of the connection between the sonic logging tubes and the grouting head. If leakage occurs, repair the leakage by welding. The top of each set of sonic logging tubes should be vertically exposed 200-500mm above the ground and fixed by welding with positioning bars. After filling each set of sonic logging tubes with clean water, seal the top opening of the sonic logging tubes.

8. The method for distributed grouting construction of interlocking piles according to claim 1, characterized in that: The grouting pressure when the grouting pump injects cement grout into the grouting head at the end of pile B is 0.8~4.0 MPa; the grouting pressure when the grouting pump injects cement grout into the grouting head on the side of pile B is 0.2~2.0 MPa.

9. The method for distributed grouting construction of interlocking piles according to claim 1, characterized in that: The design requirement for the grouting volume at each grouting end face of a single B-pile must meet the calculation formula for pile end grouting volume: ; The design requirement for the grouting volume at each grouting end face of a single B-pile must meet the calculation formula for pile side grouting volume: ; The design requirements for the grouting volume of a single B pile must meet the calculation formula for the grouting volume of a single pile: ; In the formula: This represents the empirical coefficient for the grouting volume on the side of pile B; This represents the empirical coefficient for the grouting amount at the pile tip of pile B; Indicates the number of grouting end faces on the side of pile B; Indicates the diameter of pile B; This indicates the grouting volume of a single B pile; This indicates the amount of grout applied to each grouting face at the tip of a single B-pile. This indicates the amount of grouting applied to each grouting end face on the side of a single B-pile.

10. The method for distributed grouting construction of interlocking piles according to claim 9, characterized in that: The grouting termination condition is as follows: Condition 1: The grouting volume meets the design requirements, and the average grouting pressure in the last 5 minutes reaches the grouting termination pressure. Condition 2: If the grouting volume has reached the design requirements and the average grouting pressure in the last 5 minutes is not less than 0.8 times the grouting termination pressure, the grouting volume for this layer should be increased to 110% of the design value. Condition 3: If the grouting volume has reached the design requirements and the average grouting pressure in the last 5 minutes is less than 0.8 times the grouting termination pressure, the grouting volume for this layer should be increased to 120% of the design value. Condition 4: The grouting volume is greater than 80% of the design value, and the average grouting pressure in the last 5 minutes is greater than 1.2 times the grouting termination pressure.

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