Construction method for micro-pile body material investment combination

Abstract

The present application relates to a kind of micro pile body material wagering combination construction method, can effectively handle the concrete difficult to smooth perfusion in the process of micro pile body construction, prone to pipe blockage condition, thereby affecting the quality of pile and the problem of pile efficiency, and formulate corresponding treatment measures: using cement slurry is grouted to micro pile hole, it can reduce the possibility of grouting pipe blockage, while improving the density and strength of pile body, and while grouting cement slurry, graded fine aggregate and sand are put into to increase the strength of pile body, so that the pile body is no longer damaged due to the smaller strength of cement when subjected to load, but the strength of pile body mainly depends on the strength of cement and aggregate combination itself, thereby more conducive to improve the resistance of micro pile body, so that the present application can ensure grouting smooth while ensuring the quality of pile and the efficiency of pile.

Description

Technical Field

[0001] This invention relates to the technical field of micropile construction, and in particular to a construction method combining micropile body material injection. Background Technology

[0002] In recent years, my country's urban construction has flourished, and the rational utilization of underground space has received increasing attention. With the large-scale emergence of auxiliary buildings such as high-rise buildings, podiums, sunken plazas, and parking garages, large-scale plaza-style building complexes have been formed. Because these auxiliary buildings are relatively lightweight and deeply buried, especially in cases of deep foundation pits and high groundwater levels, the buoyancy may exceed the sum of the building's own weight and counterweight, causing the building to float. This floating phenomenon not only affects the structural stability of the building but can also lead to frequent cases of building damage in engineering practice.

[0003] To ensure the structural stability and normal use of buildings, buoyancy control has become a major concern in engineering design. In practical engineering, measures such as counterweights, anti-buoyancy piles, and anti-buoyancy anchors are commonly used to address this issue. However, the counterweight method increases buoyancy by increasing the depth of the backfill layer, while the provided anti-buoyancy force is wasted. Anti-buoyancy anchors generally require prestressing technology, making the construction process relatively cumbersome. Therefore, using micro-anti-buoyancy piles is a more effective measure for buoyancy control in deep foundation pits.

[0004] In related technologies, micro-pile anti-buoyancy piles are an engineering technology used to address the buoyancy of underground structures. The design and construction of micro-pile anti-buoyancy piles aim to provide sufficient vertical bearing capacity to resist water buoyancy and ensure the stability of underground structures. However, during the construction of existing micro-pile anti-buoyancy piles, the relatively small cross-section of the pile body makes it difficult to smoothly pour concrete after mixing, and pipe blockage is prone to occur, thus affecting the pile quality and efficiency, which is not conducive to practical use. Therefore, those skilled in the art provide a construction method that combines the pouring of micro-pile body materials to solve the problems mentioned in the background technology. Summary of the Invention

[0005] To address the problems described in the background art, where the relatively small cross-section of micropiles makes it difficult to smoothly pour concrete after mixing, and also easily leads to pipe blockage, thus affecting the quality and efficiency of pile formation, this invention provides a construction method combining material pouring for micropiles.

[0006] This application provides a construction method for combining micropile material placement with the following technical solution:

[0007] A construction method combining material beading and injection for micropiles, comprising the following steps during micropile construction:

[0008] Step 1: Pour the basement floor slab cushion layer, determine and mark the location of the micropile holes according to the drawings, then drill the micropile holes using the pile hole drilling machinery, and clean the holes.

[0009] Step 2: Install the over-irrigation sleeve on the basement floor slab using expansion bolts;

[0010] Step 3: Hoist the fabricated micropile reinforcement cage into the micropile hole, and then insert the primary grouting pipe and the secondary grouting pipe into the micropile reinforcement cage, so that the bottom end of the primary grouting pipe is placed at the bottom of the micropile hole and the bottom end of the secondary grouting pipe is placed in the middle of the micropile hole.

[0011] Step 4: Add graded fine stone aggregate and sand into the micropile hole, and at the same time inject cement slurry into the micropile hole through the primary grouting pipe to perform primary grouting. When the grouting reaches the top of the pile, slowly pull out the primary grouting pipe for recycling.

[0012] Step 5: After the first grouting, let it stand for two hours, then slowly inject grout into the micropile hole through the secondary grouting pipe. At the same time as grouting, the secondary grouting pipe is pulled out for recycling.

[0013] By adopting the above technical solution, the over-grouting sleeve can prevent the overflow of over-grouted grout. During the first grouting, the cement slurry can be injected into the micropile hole from the bottom through the primary grouting pipe. During the second grouting, the cement slurry can be injected into the micropile hole from the middle through the secondary grouting pipe, thereby further ensuring the compactness of the pile body. Using cement slurry to grout the micropile hole can reduce the possibility of grouting pipe blockage, while improving the compactness and strength of the pile body. Furthermore, the addition of graded fine stone aggregate and sand during the cement slurry injection can increase the strength of the pile body, which is more conducive to improving the resistance of the micropile body. This application can ensure the quality and efficiency of pile formation while ensuring smooth grouting.

[0014] Preferably, the drilling equipment for the pile location is a geological exploration drilling rig or an anchor drilling rig, the diameter of the micropile body is less than 300 mm, and the inner diameter of the micropile hole is 10 mm to 20 mm larger than the outer diameter of the micropile body.

[0015] By adopting the above technical solution, drilling of micropile holes can be carried out using geological exploration drilling rigs or anchor drilling rigs. The slightly larger inner diameter of the micropile holes can ensure sufficient space when injecting cement slurry, thereby helping to ensure that the cement slurry can flow evenly.

[0016] Preferably, the length of the micropile reinforcement cage is 10% to 30% greater than the length of the micropile body, and the outer diameter of the micropile reinforcement cage is 10% to 20% smaller than the inner diameter of the micropile hole.

[0017] By adopting the above technical solution, the length of the micropile reinforcement cage is longer than the length of the micropile body, which ensures that the micropile reinforcement cage can fully play its role in reinforcement and tensile strength after the pile body is subjected to load during construction. The micropile reinforcement cage is smaller than the inner diameter of the micropile hole, which helps the grout to better wet and fill the gaps in the micropile hole, ensuring full contact between the grout and the wall of the micropile hole, and improving the overall strength of the micropile body.

[0018] Preferably, the micropile reinforcement cage includes several longitudinal reinforcement bars arranged in a circle, the outer walls of the longitudinal reinforcement bars are fixedly connected with spiral hoops, and the inner walls of the longitudinal reinforcement bars are uniformly welded with several stiffening hoops.

[0019] By adopting the above technical solution, several longitudinal reinforcement bars can provide the bearing capacity of the micropile body to resist the vertical and horizontal loads borne by the pile body in the foundation. Through the cooperation of spiral hoops and stiffening hoops, the longitudinal structure of the pile body can be strengthened and stabilized, improving the overall stiffness and bearing capacity of the micropile body. At the same time, a certain connection support is formed between the longitudinal reinforcement bars, which helps to share the load of the pile body.

[0020] Preferably, the over-irrigation sleeve includes symmetrically arranged arc-shaped mounting base plates, which are connected to the basement floor slab by bolts. Arc-shaped pipe walls are fixedly connected to the upper surfaces of the symmetrically arranged arc-shaped mounting base plates. The symmetrically arranged arc-shaped pipe walls are assembled into a circular pipe shape. Connecting plates are fixedly connected to both sides of the arc-shaped pipe walls, and the connecting plates on both sides of the symmetrically arranged arc-shaped pipe walls are connected by bolts.

[0021] By adopting the above technical solution, the installation position of the symmetrically arranged arc-shaped mounting base plate can be restricted by the cooperation of expansion bolts, and the symmetrically arranged arc-shaped pipe wall can be spliced ​​and fixed by the cooperation of connecting plates and bolts on both sides of the arc-shaped pipe wall.

[0022] Preferably, the spiral hoop forms a 2m densified zone below the top of the micropile, and the spacing between the spiral hoop densified zones is 100mm.

[0023] By adopting the above technical solution, the spiral hoop in the densified zone can provide sufficient longitudinal support, increasing the bending and shear resistance of the pile.

[0024] Preferably, an arc-shaped steel plate is fixedly connected inside the arc-shaped mounting base plate, and a reinforcing structure is fixedly connected to the upper surface of the arc-shaped steel plate, the reinforcing structure being located inside the arc-shaped pipe wall.

[0025] By adopting the above technical solutions, the arc-shaped steel plate can enhance the stability of the arc-shaped installation base plate, and the reinforced structure can improve the strength of the arc-shaped pipe wall, preventing the arc-shaped pipe wall from deforming during grouting.

[0026] Preferably, the reinforcing structure includes longitudinal steel bars uniformly fixedly connected to the upper surface of the arc-shaped steel plate, and several arc-shaped reinforcing ribs uniformly fixedly connected between adjacent longitudinal steel bars.

[0027] By adopting the above technical solution, the tensile strength of the arc-shaped pipe wall can be enhanced by several longitudinal steel bars, thereby improving the overall stress performance of the overfilling sleeve. The arc-shaped reinforcing bars fixedly connected between adjacent longitudinal steel bars can enhance the synergistic effect between the longitudinal steel bars and improve the overall stability of the overfilling sleeve.

[0028] In summary, the present invention has the following beneficial technical effects:

[0029] 1. The micropile material injection and construction method improves the construction process by using cement grout, increases fluidity, and reduces the possibility of pipe blockage. At the same time, the secondary grouting process ensures the compactness and strength of the pile body. Furthermore, the addition of graded fine stone aggregate and sand during the injection of cement grout increases the strength of the pile body. This allows the pile body to rely not only on the strength of cement but also to make full use of the strength of the aggregate when under stress, thereby improving the resistance of the micropile body. This application ensures both smooth grouting and high pile quality and efficiency.

[0030] 2. The construction method combining material injection with the micropile construction allows for multiple recycling and reuse of the grouting pipe, reducing costs and construction time. It meets the requirements of prefabricated construction and conforms to the concept of green construction. Furthermore, when grouting with cement slurry, the good fluidity of the cement slurry can be utilized to form a pile body similar to one with small ribs, increasing the mechanical interlocking force between the pile body and the surrounding soil layer, improving the pull-out resistance of the micropile body, and enabling the micropile body to effectively meet the foundation anti-buoyancy requirements and achieve the ideal anti-buoyancy effect.

[0031] 3. The micropile material injection and construction method combines grouting and over-grouting. During grouting, the over-grouting sleeve installed on the basement floor slab prevents the grout from overflowing. A sealing ring is installed between the over-grouting sleeve and the basement floor slab, which provides a certain degree of sealing and prevents grout from seeping out from the joint. The combination of the arc-shaped steel plate and the reinforcement structure enhances the stability of the over-grouting sleeve after installation and improves the strength of the arc-shaped pipe wall, thereby preventing deformation of the arc-shaped pipe wall during grouting. This makes the application more suitable for practical use. Attached Figure Description

[0032] Figure 1 This is a schematic diagram of the overall structure of an embodiment of the present invention;

[0033] Figure 2 This is a schematic diagram of the cross-sectional structure of a micropile in an embodiment of the present invention;

[0034] Figure 3 This is a schematic diagram of the micropile steel cage structure in an embodiment of the present invention;

[0035] Figure 4 This is a schematic diagram of the over-irrigation sleeve structure in an embodiment of the present invention;

[0036] Figure 5 This is an embodiment of the present invention. Figure 4 Schematic diagram of the cross-sectional structure at point AA;

[0037] Figure 6 This is a schematic diagram of the arc-shaped steel plate and the reinforcement structure in an embodiment of the present invention.

[0038] Explanation of reference numerals in the attached drawings: 1. Micropile body; 2. Basement floor slab cushion layer; 3. Micropile hole; 4. Micropile reinforcement cage; 401. Longitudinal reinforcement of the pile body; 402. Spiral hoop; 403. Stiffening hoop; 5. Primary grouting pipe; 6. Secondary grouting pipe; 7. Over-grouting sleeve; 701. Arc-shaped mounting base plate; 702. Arc-shaped pipe wall; 703. Connecting plate; 8. Arc-shaped steel plate; 9. Reinforcement structure; 901. Longitudinal reinforcement; 902. Arc-shaped reinforcing bar. Detailed Implementation

[0039] The following is in conjunction with the appendix Figure 1-6 The present invention will be described in further detail below.

[0040] Example 1

[0041] This invention discloses a construction method combining material injection and application for micropiles. (Refer to...) Figure 1 and Figure 2 This micropile material injection and construction method addresses the problems encountered during the construction of micropile body 1, where the relatively small cross-section of the micropile body 1 makes it difficult to smoothly pour concrete after mixing, and also easily leads to pipe blockage, thus affecting the quality and efficiency of pile formation. Corresponding solutions have been developed for these issues.

[0042] Step 1: Pour the basement floor slab cushion layer 2. After the basement floor slab cushion layer 2 is poured, determine the location of the micropile holes 3 according to the drawings and mark them with red paint for the next step of construction. Set up fixed points outside the anti-buoyancy design range and mark them clearly with red paint for use in surveying, restoration, and inspection of piles, so as to ensure that the hole positions can be frequently re-measured during construction. Drill the micropile holes 3 at the marked locations using pile drilling machinery and clean the holes. The pile drilling machinery is a geological exploration drilling rig or an anchor drilling rig. When using the geological exploration drilling rig... The drilling rig is typically composed of a drill rod, drill bit, turntable, hydraulic cylinder, and conveying system. The turntable controls the rotation and downward pressure of the drill rod, the hydraulic cylinder provides the downward pressure, and the conveying system removes drill cuttings and mud from the borehole. After the micropile hole 3 is drilled, the hole needs to be cleaned. Cleaning the pile hole is an important step to ensure the construction quality of the micropile body 1. The cleaning process is mainly to remove debris, mud, water, etc. from the micropile hole 3 to ensure good adhesion between the micropile body 1 and the foundation.

[0043] Furthermore, during the cleaning of the micropile hole 3, the cleaning liquid needs to be injected into the micropile hole 3 from the bottom through a pipeline during the construction process. This ensures that the cleaning liquid can fully cover the bottom and sidewalls of the micropile hole 3. After the cleaning liquid is injected, it is stirred by a stirring device to enhance the effect of removing impurities. The impurities suspended in the cleaning liquid are then lifted to the hole opening and discharged by a pump or other equipment. After completing one round of cleaning, the cleaning operation needs to be repeated according to actual needs until all impurities in the micropile hole 3 are removed. After the cleaning is completed, the cleanliness of the micropile hole 3 needs to be checked to ensure that there are no residual mud, cement slurry or other impurities.

[0044] Step 2: Install the over-filled sleeve 7 on the basement floor slab cushion layer 2 using expansion bolts. The over-filled sleeve 7 can be a PVC sleeve, which is mainly made of polyvinyl chloride resin. This material has the characteristics of corrosion resistance, chemical resistance, good insulation, and good fire resistance. This makes the over-filled sleeve 7 highly durable and able to maintain stable performance for a long time. It is not easily affected by climate change, moisture, and ultraviolet rays. The over-filled sleeve 7 is connected to the micropile hole 3. The over-filled sleeve 7 can prevent the over-filled grout from overflowing. A sealing ring is installed between the contact surface of the over-filled sleeve 7 and the basement floor slab cushion layer 2. The sealing ring can play a certain sealing role between the basement floor slab cushion layer 2 and the over-filled sleeve 7, preventing the grout from seeping out from the joint. After the micropile body 1 is formed, the over-filled part of the over-filled sleeve 7 and the pile body needs to be removed.

[0045] Step 3: Based on the design and structural requirements, determine the cutting length of the micropile reinforcement cage 4. The length of the micropile reinforcement cage 4 can be designed to be 10% to 30% greater than the length of the micropile body 1. This ensures that the micropile reinforcement cage 4 can fully exert its reinforcement and tensile strength functions after the pile body is subjected to load during construction. Furthermore, the outer diameter of the micropile reinforcement cage 4 is 10% to 20% smaller than the inner diameter of the micropile hole 3. This helps the grout to better impregnate and fill the voids in the micropile hole 3, ensuring sufficient contact between the grout and the wall of the micropile hole 3, thereby improving the micropile's strength. The overall strength of the pile body 1 is ensured by grouting, and the micropile reinforcement cage 4 is wrapped with grout to ensure that there is a sufficient protective layer around the micropile reinforcement cage 4 to prevent corrosion. The fabricated micropile reinforcement cage 4 is then hoisted into the micropile hole 3 using a tower crane or truck crane. The primary grouting pipe 5 and the secondary grouting pipe 6 are then inserted into the micropile reinforcement cage 4, with the bottom end of the primary grouting pipe 5 placed at the bottom of the micropile hole 3 and the bottom end of the secondary grouting pipe 6 placed in the middle of the micropile hole 3. The grouting pipes and the micropile reinforcement cage 4 can be reinforced with fasteners.

[0046] Step 4: Add graded fine stone aggregate and sand into the micropile hole 3, and simultaneously inject cement slurry into the micropile hole 3 through the primary grouting pipe 5 to perform primary grouting. Since the bottom end of the primary grouting pipe 5 is placed at the bottom of the micropile hole 3, the cement slurry can be injected into the micropile hole 3 from the bottom. When the grouting reaches the top of the pile, slowly grout while pulling out the primary grouting pipe 5 for recycling.

[0047] Specifically, the use of cement grout has the advantage of preventing grouting pipe blockage, especially when the diameter of the micropile body 1 is small and there are many longitudinal bars and stirrups inside the pile body. By using cement grout, it helps to ensure that the grout flows smoothly when injected into the pipe and avoids pipe blockage. At the same time, while grouting, the injection of graded fine stone aggregate and sand into the micropile hole 3 can effectively enhance the strength of the micropile body 1. This process makes the micropile body 1 no longer damaged due to the low strength of cement when subjected to load. Instead, the strength of the micropile body 1 mainly depends on the strength of the bond between cement and aggregate, which is more conducive to improving the resistance of the micropile body 1.

[0048] Step 5: After the first grouting, let it stand for two hours. Then, slowly inject the second grouting into the micropile hole 3 through the secondary grouting pipe 6. At the same time as injecting the cement slurry, pull out the secondary grouting pipe 6 for recycling. The bottom end of the secondary grouting pipe 6 is placed in the middle of the micropile hole 3, which can further ensure the compactness of the pile body and improve the compactness and strength of the micropile body 1 after it is formed.

[0049] In this embodiment, to ensure smooth grouting during the construction of the micropile body 1 and improve the quality and efficiency of pile formation, this application improves the construction process of the micropile body 1. Cement slurry has better fluidity and is easier to fill the pile hole, reducing the possibility of pipe blockage, thereby improving the density and strength of the pile body. By introducing a secondary grouting process with a secondary grouting pipe 6, the density of the pile body can be further improved, ensuring the density and strength of the pile body. This process ensures the continuity and uniformity of grouting, providing stability and reliability for the formation of the micropile body 1. In order to avoid insufficient pile body strength due to relying solely on cement slurry, this application adds graded fine stone aggregate and sand while grouting cement slurry to increase the strength of the pile body. When the pile body is subjected to load, it will not be damaged due to the low strength of cement, but the strength of the pile body will mainly depend on the strength of the bond between cement and aggregate, which is more conducive to improving the resistance of the micropile body 1.

[0050] Furthermore, the most significant failure mode of the micropile body 1 with anti-buoyancy function is the large buoyancy, which causes the entire pile to detach from the soil and be pulled upwards, thus losing its function. This application uses cement grout, which has good fluidity, allowing it to partially penetrate into the soil layer around the pile body, forming a pile similar to one with small ribs. This increases the mechanical interlocking force between the micropile body 1 and the surrounding soil layer, preventing the entire pile body from being pulled out due to friction alone, thereby better fulfilling the anti-buoyancy function.

[0051] Through steps one through five, the micropile body 1 is completed by grouting, forming a micropile with a diameter of less than 300 mm. When the diameter of the micropile body 1 is less than 300 mm, the inner diameter of the micropile hole 3 needs to be 10 mm to 20 mm larger than the outer diameter of the micropile body 1. This ensures sufficient space during the grouting process, helps ensure uniform flow of the grout, prevents the formation of voids and air bubbles, and thus improves the overall quality and performance of the pile.

[0052] In a further preferred embodiment of the invention, such as Figure 2 and Figure 3As shown, the micropile reinforcement cage 4 includes several circumferentially arranged longitudinal reinforcement bars 401. These longitudinal reinforcement bars 401 can be made of high-strength steel bars, which can provide the bearing capacity of the micropile body 1 to resist the vertical and horizontal loads borne by the pile body in the foundation. The outer walls of the longitudinal reinforcement bars 401 are fixedly connected with spiral hoops 402. The spiral hoops 402 can be made of steel bars with a diameter of 8 mm. The spiral hoops 402 form a reinforced zone within 2 m below the top of the micropile body 1. The spacing of the reinforced zone of the spiral hoops 402 is 100 mm. The spiral hoops 402 in the reinforced zone can provide sufficient longitudinal support and increase the bending and shear resistance of the pile body. Several stiffening hoops 403 are uniformly welded to the inner walls of the longitudinal reinforcement bars 401. The stiffening hoops 403 can strengthen and stabilize the longitudinal structure of the pile body, improve the overall stiffness and bearing capacity of the micropile body 1, and at the same time form a certain connection support between the longitudinal reinforcement bars 401, which helps to distribute the load of the pile body.

[0053] In a further preferred embodiment of the invention, such as Figure 1 , Figure 4 and Figure 5 As shown, the overfill sleeve 7 includes symmetrically arranged arc-shaped mounting base plates 701, which can be assembled into a ring. The symmetrically arranged arc-shaped mounting base plates 701 are connected to the basement floor slab 2 by bolts. Arc-shaped pipe walls 702 are fixedly connected to the upper surface of each of the symmetrically arranged arc-shaped mounting base plates 701. By cooperating with expansion bolts, the installation position of the symmetrically arranged arc-shaped pipe walls 702 can be restricted, allowing the symmetrically arranged arc-shaped pipe walls 702 to be assembled into a circular pipe shape. Furthermore, the inner wall of the arc-shaped pipe wall 702 can be coated with a layer of... An anti-stick coating, such as polyethylene, has good anti-adhesion properties and is widely used to coat the inner wall of PVC sleeves. It can prevent cement slurry from adhering. Furthermore, a handle is fixedly connected to the outer wall of the arc-shaped pipe wall 702, which facilitates the installation and removal of the overfill sleeve 7 by the user. Connecting plates 703 are fixedly connected to both sides of the arc-shaped pipe wall 702. The connecting plates 703 on both sides of the symmetrically arranged arc-shaped pipe wall 702 are connected by bolts. By cooperating with the bolts, the symmetrically arranged arc-shaped pipe walls 702 can be spliced ​​and fixed.

[0054] Example 2

[0055] This embodiment is an improvement based on Embodiment 1, please refer to the following for details. Figure 4 , Figure 5 and Figure 6As shown, an arc-shaped steel plate 8 is fixedly connected inside the arc-shaped mounting base plate 701. The arc-shaped steel plate 8 has evenly spaced mounting holes. When the arc-shaped mounting base plate 701 is installed, the arc-shaped steel plate 8 can enhance the stability of the installation. A reinforcing structure 9 is fixedly connected to the upper surface of the arc-shaped steel plate 8. The reinforcing structure 9 is located inside the arc-shaped pipe wall 702. The reinforcing structure 9 can improve the strength of the arc-shaped pipe wall 702 and can minimize the deformation of the arc-shaped pipe wall 702 during grouting.

[0056] Specifically, the reinforcing structure 9 includes longitudinal reinforcing bars 901 uniformly fixedly connected to the upper surface of the arc-shaped steel plate 8. The longitudinal reinforcing bars 901 can be made of steel bars. Several longitudinal reinforcing bars 901 can enhance the tensile strength of the arc-shaped pipe wall 702. Especially after over-grouting, the longitudinal reinforcing bars 901 can withstand part of the tensile force, improve the overall stress performance of the over-grouting sleeve 7, and help ensure that the over-grouting sleeve 7 can maintain stability after grouting. Several arc-shaped reinforcing bars 902 are uniformly fixedly connected between adjacent longitudinal reinforcing bars 901. The arc-shaped reinforcing bars 902 can be made of arc-shaped steel bars. By fixing the arc-shaped reinforcing bars 902 between adjacent longitudinal reinforcing bars 901, the position between adjacent longitudinal reinforcing bars 901 can be restricted, and the synergistic effect between longitudinal reinforcing bars 901 can be enhanced. This helps to form an integral frame structure and improve the overall stability of the over-grouting sleeve 7.

[0057] The implementation principle of the micropile material injection and construction method of this invention is as follows:

[0058] In use, cement grout is used to grout the micropile holes 3, which makes it easier to fill the holes and reduces the possibility of grouting pipe blockage, thereby improving the density and strength of the pile body. By introducing a secondary grouting process with a secondary grouting pipe 6, the density and strength of the micropile body 1 can be further improved. At the same time as grouting cement grout, graded fine stone aggregate and sand are added to increase the strength of the pile body. This makes the pile body no longer damaged due to the low strength of cement when subjected to load. Instead, the strength of the pile body mainly depends on the strength of the bond between cement and aggregate, which is more conducive to improving the resistance of the micropile body 1. This application can ensure the quality and efficiency of pile formation while ensuring smooth grouting.

[0059] During grouting, an over-grouting sleeve 7 installed on the basement floor slab cushion 2 prevents the over-grouting grout from overflowing. A sealing ring is installed between the contact surface of the over-grouting sleeve 7 and the basement floor slab cushion 2. The sealing ring can play a certain sealing role between the basement floor slab cushion 2 and the over-grouting sleeve 7, preventing the grout from seeping out from the joint. The arc-shaped steel plate 8 and the reinforcing structure 9 installed inside the over-grouting sleeve 7 enhance the stability of the over-grouting sleeve 7 after installation, and at the same time improve the strength of the arc-shaped pipe wall 702 of the over-grouting sleeve 7, thereby preventing the arc-shaped pipe wall 702 from deforming during grouting, making this application more conducive to practical use.

[0060] The above are all preferred embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Therefore, all equivalent changes made in accordance with the structure, shape and principle of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A construction method combining material injection and micropile construction, characterized in that, During the construction of the micropile body (1), the construction method of combining the material of the micropile body (1) includes the following steps: Step 1: Pour the basement slab cushion layer (2), determine and mark the location of the micro pile holes (3) according to the drawings, then drill the micro pile holes (3) using the pile hole drilling machinery and clean the holes; Step 2: Install the over-irrigation sleeve (7) on the basement floor slab (2) using expansion bolts. Step 3: Hoist the fabricated micro pile reinforcement cage (4) into the micro pile hole (3), and then insert the primary grouting pipe (5) and the secondary grouting pipe (6) into the micro pile reinforcement cage (4), so that the bottom end of the primary grouting pipe (5) is placed at the bottom of the micro pile hole (3), and the bottom end of the secondary grouting pipe (6) is placed in the middle of the micro pile hole (3); Step 4: Add graded fine stone aggregate and sand into the micro pile hole (3), and at the same time inject cement slurry into the micro pile hole (3) through the primary grouting pipe (5) to perform primary grouting. When the grouting reaches the top of the pile, slowly grout while pulling out the primary grouting pipe (5) for recycling. Step 5: After the first grouting, let it stand for two hours, then slowly inject grout into the micro pile hole (3) through the secondary grouting pipe (6), and pull out the secondary grouting pipe (6) at the same time for recycling; The drilling equipment for the pile location is a geological exploration drilling machine or an anchor drilling machine. The diameter of the micro pile body (1) is less than 300 mm, and the inner diameter of the micro pile hole (3) is 10 mm to 20 mm larger than the outer diameter of the micro pile body (1). The length of the micropile reinforcement cage (4) is 10% to 30% greater than the length of the micropile body (1), and the outer diameter of the micropile reinforcement cage (4) is 10% to 20% smaller than the inner diameter of the micropile hole (3). The micro pile reinforcement cage (4) includes several pile body longitudinal bars (401) arranged in a circle. The outer walls of the pile body longitudinal bars (401) are fixedly connected with spiral hoops (402), and the inner walls of the pile body longitudinal bars (401) are uniformly welded with several stiffening hoops (403). The over-irrigation sleeve (7) includes symmetrically arranged arc-shaped mounting base plates (701). The symmetrically arranged arc-shaped mounting base plates (701) are connected to the basement floor slab cushion layer (2) by bolts. The upper surface of the symmetrically arranged arc-shaped mounting base plates (701) is fixedly connected with arc-shaped pipe walls (702). The symmetrically arranged arc-shaped pipe walls (702) are assembled into a circular pipe shape. The two sides of the arc-shaped pipe walls (702) are fixedly connected with connecting plates (703). The connecting plates (703) on both sides of the symmetrically arranged arc-shaped pipe walls (702) are connected by bolts. The spiral hoop (402) to the top of the micropile (1) within 2m is the densified zone, and the spacing of the spiral hoop (402) densified zone is 100mm. An arc-shaped steel plate (8) is fixedly connected inside the arc-shaped mounting base plate (701), and a reinforcing structure (9) is fixedly connected to the upper surface of the arc-shaped steel plate (8). The reinforcing structure (9) is located inside the arc-shaped pipe wall (702). The reinforcing structure (9) includes longitudinal steel bars (901) uniformly fixedly connected to the upper surface of the arc-shaped steel plate (8), and several arc-shaped reinforcing bars (902) are uniformly fixedly connected between adjacent longitudinal steel bars (901).

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