Construction method of long screw pressurized rotary jet composite foundation and pile foundation based on solid waste utilization

Abstract

The application belongs to the technical field of foundation construction, and particularly relates to a long spiral pressure grouting jet grouting composite foundation and pile foundation construction method based on solid waste utilization, which comprises the following steps: construction preparation, selecting a long spiral drill tool with multiple jet grouting holes and jet air holes, connecting the jet grouting holes with a grouting device and the jet air holes with a high-pressure air pump, determining a pile position, jet grouting or fixed jet grouting to a design elevation for the target pile position, jetting high-pressure air through the jet air holes during jet grouting, pressure grouting after drilling to the design elevation for the target pile position again, jet grouting or fixed jet grouting during pressure grouting, the slurry used for pressure grouting containing solid waste, laying a cushion layer after pile head chiseling to form a composite foundation or a pile foundation, inserting a pile body support structure into the pile hole after pressure grouting, and the pressure grouting slurry comprising cement or concrete. The application jet grouts during pressure grouting, eliminates the obvious interface between the pile and the soil, improves the bearing capacity, and realizes resource utilization by using solid waste.

Description

Technical Field

[0001] This invention belongs to the field of foundation construction technology, and particularly relates to a construction method for a long spiral pressure grouting and jet grouting composite foundation and pile foundation based on solid waste utilization. Background Technology

[0002] In the field of building foundation construction, the pile-forming process of composite foundations and pile foundations directly affects the project quality and construction efficiency. Long spiral drilling rigs are widely used due to their ease of construction and controllable costs, and a large number of such rigs are currently available on the market. To improve equipment utilization, some technologies have been explored to modify long spiral drilling rigs for constructing long spiral mixing piles, long spiral jet grouting mixing piles, long spiral pneumatic down-the-hole hammer vibratory jet grouting piles, and anti-pull-out anchors. These modification schemes each have advantages in harder soil layers, longer pile bodies, or when encountering hard gravel or even rock layers, and can solve some construction problems.

[0003] However, the aforementioned modification schemes all share a common drawback when used for composite foundations or pile foundations: they rely on the original soil and have high requirements for the grout, making it impossible to utilize solid waste. When peat layers are present in the soil, the peat does not react with cement, resulting in unsatisfactory effects regardless of whether it is used for composite foundations, pile foundations, curtain walls, or slope protection piles. Although pressure-grown cement-soil piles do not rely on the original soil, their pile-forming process results in a clear interface between the concrete pile and the soil on the pile side, preventing the lateral friction from achieving the effect of jet grouting. Studies have shown that the lateral friction can differ by four to five times between the presence and absence of a clear interface between the pile and the soil. Furthermore, widely used methods both domestically and internationally, such as cement-soil piles with precast pipe piles and steel pipe piles, including mixing piles with reinforcing cores, jet grouting piles with reinforcing cores, and mixed-grouting piles with reinforcing cores, also rely on the original soil and suffer from the aforementioned common problems.

[0004] Therefore, there is an urgent need for a composite foundation and pile foundation construction method based on solid waste utilization using long spiral pressure grouting and fixed jet grouting piles. Summary of the Invention

[0005] The purpose of this invention is to provide a construction method for a long spiral pressure grouting and jet grouting composite foundation and pile foundation based on solid waste utilization, so as to solve the above-mentioned problems.

[0006] To achieve the above objectives, the present invention provides the following solution: The construction method for long spiral pressure grouting and jet grouting composite foundation and pile foundation based on solid waste utilization includes the following steps: Construction preparation includes site preparation and equipment preparation. Among them, a long spiral drill with multiple grouting holes and air jet holes is selected, and the grouting holes are connected to the grouting equipment and the air jet holes are connected to the high-pressure air pump. Determine the pile location, including pile location positioning and marking; The target pile location is subjected to rotary grouting or fixed grouting to the design elevation. During rotary grouting, cement grout is sprayed out through the grouting holes and high-pressure air is sprayed out through the air grouting holes. After drilling the target pile position to the design elevation again, pressure grouting is carried out, and jet grouting or fixed jet grouting is carried out at the same time. The grout used for pressure grouting contains solid waste. After chiseling the pile head, a cushion layer is laid to form a composite foundation or pile foundation; After pressure grouting, a pile support structure is inserted into the pile hole.

[0007] Optionally, the grout used for pressure grouting may include concrete or cement.

[0008] Optionally, the concrete includes one or more of the following: cohesive soil, silt, sandy soil, and gravelly soil.

[0009] Optionally, the fluidity of the concrete is 500-600 mm.

[0010] Optionally, the concrete slump is 180–220 mm.

[0011] Optionally, during rotary jet grouting, the slurry pressure is 20–25 MPa.

[0012] Optionally, the pile support structure is a steel section, a reinforcing cage, a reinforcing steel strand cage, or a precast pile; When the grouting fluid is concrete, the steel cage and the steel strand cage are used as the pile support structure. When the grouting fluid is concrete, steel sections and precast piles are used as the pile support structure.

[0013] Optionally, the precast piles are hollow pipe piles or square piles.

[0014] Optionally, the steel section is a steel pipe.

[0015] Compared with the prior art, the present invention has the following advantages and technical effects: This scheme employs a construction technique that combines long spiral grouting with jet grouting. While grouting, jet grouting or fixed-point jet grouting is performed simultaneously, with the grout pressure controlled between 20 and 25 MPa. This effectively expands the pile diameter and the contact width between the pile and the soil during grouting, allowing the grout to fully penetrate the surrounding soil and eliminating a distinct interface between the grouting pile and the soil beside the pile. This avoids the drawbacks of traditional mixing piles and jet grouting piles that rely on in-situ soil. The grout flowability is controlled between 500 and 600 mm, ensuring the pumpability and workability of the grout and guaranteeing a continuous and smooth grouting process. The grout used in grouting contains solid waste, specifically one or more of cohesive soil, silt, sandy soil, and gravelly soil. Construction waste tailings or in-situ soil are used instead of traditional sand and gravel as the main material for concrete, achieving resource utilization of solid waste and reducing engineering material costs. After pressure grouting, a pile support structure such as steel sections, reinforcing cages, steel strand cages, or precast piles is inserted into the pile hole. The appropriate structure is selected based on the type of grout, allowing the pile to simultaneously possess the side friction advantages of pressure-grouted jet grouting piles and the strength advantages of core piles, significantly improving the bearing capacity of single piles and composite foundations. This solution solves the fundamental problem of existing technologies relying on in-situ soil, which leads to the bearing capacity being controlled by the weakest layer. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly described below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. Figure 1 This is a process flow diagram of the present invention.

[0017] Figure 2 This is a process flow diagram for application example 1 of the present invention.

[0018] Figure 3 This is a process flow diagram for application example 2 of the present invention.

[0019] Figure 4 This is a process flow diagram for application example 3 of the present invention.

[0020] Figure 5 Example 4 of the present invention is a process flow diagram. Detailed Implementation

[0021] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0022] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0023] Reference Figures 1 to 5 This invention discloses a construction method for a long spiral pressure grouting and jet grouting composite foundation and pile foundation based on solid waste utilization, comprising the following steps: Construction preparation includes site preparation and equipment preparation. Among them, a long spiral drill with multiple grouting holes and air jet holes is selected, and the grouting holes are connected to the grouting equipment and the air jet holes are connected to the high-pressure air pump. Determine the pile location, including pile location positioning and marking; The target pile location is subjected to jet grouting or fixed jet grouting to the design elevation. During jet grouting, cement grout is sprayed out through the grouting holes and high-pressure air is sprayed out through the air grouting holes. After drilling the target pile position down to the design elevation again, pressure grouting is carried out, and jet grouting or fixed jet grouting is carried out at the same time. The grout used for pressure grouting contains solid waste. After chiseling the pile head, a cushion layer is laid to form a composite foundation or pile foundation; After pressure grouting, a pile support structure is inserted into the pile hole.

[0024] This plan begins with construction preparation, using a long spiral drilling tool with multiple grouting holes and air jets. The grouting holes are connected to the grouting equipment, and the air jets are connected to a high-pressure air pump. After determining the pile location, the target pile location is first jet-grouted or fixed-point grouting to the design elevation. During jet-grouting, high-pressure cement grout is ejected through the grouting holes, and high-pressure airflow is ejected through the air jets. Then, the target pile location is drilled again to the design elevation, and pressure grouting is performed simultaneously with jet-grouting or fixed-point grouting. The grout used for pressure grouting contains solid waste. Finally, after chiseling the pile head, a cushion layer is laid to form a composite foundation or pile foundation. This plan, through the combined construction of jet-grouting and pressure grouting, ensures that the grout is thoroughly mixed with the soil around the pile, eliminating a clear interface between the pile and the soil, and simultaneously utilizing the solid waste-containing grout to achieve solid waste utilization.

[0025] This invention utilizes a construction process combining long spiral grouting and jet grouting. By modifying the long spiral drilling tool to include a spiral rod with a high-pressure grouting pipe and a ventilation pipe, the high-pressure grouting pipe and ventilation pipe are positioned outside the spiral rod cavity, closely attached to the hollow pipe, and connected from top to bottom. The high-pressure grouting pipe and ventilation pipe can rotate with the spiral rod, enabling separate jet grouting or fixed jet grouting, or simultaneous jet grouting or fixed jet grouting with pressure grouting of concrete (or concrete). This allows for simultaneous pressure grouting of concrete (or concrete) and jet grouting or fixed jet grouting when constructing composite foundation piles, without relying on the original soil conditions. Mixing concrete (or grout) on the ground surface, with precise metering at the mixing plant, ensures uniform and stable quality of the concrete (or grout), and can be prepared entirely according to design requirements. At the same time, jet grouting or fixed jet grouting expands the diameter of the grouting pile or the width of contact with the soil, making the boundary between the grouting pile and the soil less obvious. This avoids the drawbacks of traditional mixing piles, jet grouting piles, or mixed grouting piles that rely on the original soil, or form low-strength, slow-setting cement-soil piles when encountering silt, or fail to form piles when encountering peat soil, or form hard solidified bodies when encountering sand and gravel layers. As a result, the strength of the pile body is controlled by the original soil, the bearing capacity is controlled by the weakest layer, and the quality cannot be guaranteed.

[0026] In this embodiment, the long spiral drill bit is modified as follows: The long spiral drill bit is a long spiral drill bit with multiple grouting holes and air jet holes. The grouting holes and air jet holes are symmetrically arranged, and both the grouting holes and air jet holes are covered by long spiral blades. The opening or bend of the power head of the long spiral drill is connected to the grouting pipe and the air supply pipe. A single-action device is installed at the connection. The grouting hole is connected to the cement grouting pump and is equipped with a grouting tank, vibrating screen and grout storage tank. The air jet hole is connected to the air compressor.

[0027] After forming jet grouting piles with grouting concrete (or grout), precast pipe piles or steel cores are inserted to form a composite foundation or pile foundation, or a reinforcing cage is inserted after forming jet grouting piles with grouting concrete to form a pile foundation. This can greatly improve the bearing capacity of a single pile and also improve the bearing capacity of the composite foundation.

[0028] As an alternative implementation, the grout used for pressure grouting includes concrete or cement.

[0029] The grout used in pressure grouting includes concrete or cementitious material. The concrete or cementitious material is precisely mixed at the ground surface by a mixing plant to ensure that the grout is uniform and of stable quality. The mix proportion can be completely controlled according to design requirements and does not depend on the original soil.

[0030] As an alternative implementation, concrete includes one or more of clayey soil, silt, sandy soil and gravelly soil.

[0031] As an optional implementation method, the flowability of the concrete is 500-600 mm.

[0032] As an optional implementation method, the concrete slump is 180–220 mm.

[0033] The aforementioned soil types are widely available and inexpensive, and can be used to replace traditional sand and gravel, thereby realizing the resource utilization of solid waste and reducing engineering costs.

[0034] The main components of concrete include: One or more of the following: cohesive soil, silt, sandy soil, and gravelly soil; if necessary, two types of soil may be mixed together.

[0035] Construction waste tailings can also be used as the main material, and if necessary, they can be mixed with clay.

[0036] Cement or sulfur gypsum is used as a curing agent.

[0037] In this embodiment, the basic concrete formula is as follows: Mix 1000 kg of cohesive soil and sandy soil at a 1:1 ratio, add 100 kg to 150 kg of cement, and then add to a forced mixer containing 700 to 750 liters of water. Mix for 1.5 to 2.0 minutes until homogeneous, with a flowability of 500 to 600 mm. Accelerators, water-reducing agents, and other additives may be added as needed for the project.

[0038] This fluidity range ensures that the grout has good pumpability and workability, guaranteeing a continuous and smooth pressure grouting process, while also allowing the grout to fully contact and mix with the soil around the pile during pressure grouting and jet grouting, eliminating the pile-soil interface.

[0039] As an optional implementation method, the slurry pressure is 20-25 MPa during rotary jetting.

[0040] This pressure allows the grout to effectively expand the pile diameter and the contact width between the pile and the soil during the pressure grouting process, ensuring that the grout fully penetrates into the soil around the pile and eliminating the obvious boundary between the pile and the soil.

[0041] As an optional implementation method, the pile support structure is a steel section, a reinforcing cage, a steel strand cage, or a precast pile; When the grouting fluid is concrete, steel cages or steel strand cages are used as pile support structures. When the grouting fluid is concrete, steel sections and precast piles are used as the pile support structure.

[0042] The above-mentioned differentiation and matching not only ensures the material compatibility between the core pile and the grout, but also provides a flexible core selection for different engineering needs.

[0043] As an alternative implementation method, the precast piles are hollow pipe piles or square piles.

[0044] Hollow pipe piles and square piles are both mature standard precast components with controllable quality and convenient construction. After insertion, they can form a composite force structure with the surrounding concrete piles, further improving the bearing capacity of the piles.

[0045] As an optional implementation method, the steel section is a steel pipe.

[0046] As a specific form of structural steel, steel pipe has advantages such as high strength, regular cross-section, and low insertion resistance. It is suitable for pile foundation projects with high requirements for compressive or tensile bearing capacity. At the same time, steel pipe has good bonding performance with concrete piles.

[0047] The following detailed description is provided in conjunction with specific embodiments.

[0048] 1. Construction preparation: 1) Collect data, conduct on-site surveys, and carefully prepare the construction organization design; 2) Clear underground and above-ground obstacles at the construction site, level the site, and arrange site facilities reasonably to ensure normal construction.

[0049] 3) Preparation of raw materials: (1) All materials used shall comply with the design and national and local standards; (2) Cement must have a certificate of quality from the manufacturer. Upon receipt, the type, grade, packaging, and date of manufacture of cement should be inspected and accepted, and stored in accordance with relevant regulations. For every 200 tons of cement purchased, samples must be taken and sent for testing. The samples to be sent for testing should be small amounts from each of the 10 bags and mixed thoroughly. H-beams must be provided with a certificate of quality from the manufacturer.

[0050] (3) The steel section welding is carried out with the help of a 15T crawler crane. The welding method is steel section butt welding. The weld meets the design specifications. The steel section welding acceptance adopts the method of welding and acceptance at the same time.

[0051] (4) Conduct sampling and testing of all relevant raw materials in accordance with regulations to ensure the quality of raw materials.

[0052] 4) Mechanical equipment and auxiliary equipment: Modified long spiral drilling tools, mud system equipment, vibratory pile extractor, hydraulic excavator, air compressor, etc.

[0053] 2. Measurement and layout: First, measure and mark the stake positions on the leveled ground. Use measuring instruments to mark the two ends to prevent deviations in the stake positions and check them at any time. The stake positions are usually marked by drilling a deep hole in the ground with a steel rod or hole drill, filling it with white lime powder, and inserting a wooden stick or steel rod or other obvious marker at the stake position.

[0054] 3. Drilling rig positioning and drilling: At the designated pile location, operators strictly control the movement of the drilling rig's pile frame to ensure the borehole axis is in place and that the verticality deviation of the drilling tools is within 0.5%. Simultaneously, they control the drilling depth to meet the specified standards, marking the drilling depth on the drill pipe.

[0055] 4. Drilling and jetting, pressure injection and lifting of drill string: According to the depth specified in the design, the drilling rig maintains a constant screw speed during the entire drilling and lifting process, and uses high-pressure grouting and air jetting to mix the cement and soil in the hole, ensuring that the entire pile is fully and evenly mixed and ensuring the quality of the mixed pile.

[0056] 1) Cement grout preparation: Select different types of cement according to different strata and groundwater levels, and determine different water-cement ratios. The final water-cement ratio should be determined through design requirements and on-site tests. Generally, the water-cement ratio can be selected from 1.0 to 1.5. In addition, an appropriate amount of admixtures can be added according to the actual situation.

[0057] 2) Concrete preparation: If on-site preparation is adopted, cohesive soil and sandy soil can be selected and batched in the test ratio (which can be set in advance as 1:1) using a batching machine. Add a certain amount of cement to the hopper, and add it together to a forced mixer filled with water. Mix for 1 to 2 minutes until uniform. Test the slump or flowability and make test blocks.

[0058] If the mixing plant is commissioned to prepare the mixture, the formula and performance requirements can be determined in advance. After mixing, the mixture is transported to the site by tanker truck. When the mixture flows into the ground pump hopper, samples can be taken for slump or flowability tests and test blocks can be made.

[0059] 3) Determine the drilling speed based on soil and water level conditions, and adjust it beforehand using a frequency converter. Drill while simultaneously grouting; once the designed depth is reached, grout (or stationary grouting) is applied to raise the drill bit (in aquifer areas, this can be repeated multiple times) until the borehole opening. Multiple up-and-down grouting operations throughout the borehole ensure a more uniform cement-soil mixture. After grouting, once the drill bit reaches the bottom, connect the ground pump hose and begin pressurizing and grouting the concrete as it rises, while simultaneously applying stationary grout until the drill bit is pulled out. Control the grout pressure at 20–25 MPa, and adjust the grout flow rate according to the actual drilling speed and the characteristics of the underground soil. This process can be simply referred to as "three-stage grouting and one-stage grouting."

[0060] 5. Insertion of steel sections or precast piles: Before the concrete in the borehole begins to set and harden, a vibratory pile extractor is used to lift the steel section or precast pile of a fixed length and insert it into the designated position. The pile is then inserted to the designed depth by its own weight and the downward force. If the designed depth cannot be reached, the vibratory hammer is turned on to vibrate and insert the pile.

[0061] A vibratory pile extractor is used to lift the steel section, which then sinks under its own weight and is transported downwards. If the designed depth cannot be reached, a vibratory hammer is activated to vibrate and insert the pile. During insertion, reliable guiding measures are taken to ensure the verticality of the steel section. The steel section can be round steel, or other types of steel can be selected depending on the stress. Precast piles can be hollow pipe piles or square piles.

[0062] If jet grouting piles with pressure grouting concrete are used, steel cages or steel strand cages can be inserted to form pile foundations.

[0063] Application Example 1: Pressure-grown jet grouting concrete pile composite foundation A composite foundation project was designed using a pressure-grown and jet grouting concrete pile composite foundation. The concrete was supplied by a mixing plant, and the strength of the 28-day test block was not less than 10 MPa. The pile length was 12 m, the diameter of the pressure-grown pile was 400 mm, and the diameter of the jet grouting pile was not less than 600 mm. The static load test results showed that the bearing capacity of a single pile was more than 4 times that of a mixing pile of the same diameter and more than 2 times that of a jet grouting pile of the same diameter. Moreover, it utilized solid waste, demonstrating its unique advantages.

[0064] Application Example 2: Pressure-grown, jet-jet-grown concrete composite foundation with precast pipe piles A composite foundation engineering project was designed using a pressure-grown, jet-grouting, and precast pipe pile composite foundation. The concrete was supplied by a mixing plant, and the 28-day test block strength was no less than 2 MPa. The pile length was 15m, the diameter of the pressure-grown pile was 400mm, the diameter of the jet-grouting pile was no less than 600mm, and 12m long precast pipe piles with a diameter of 300mm were inserted. The 28-day static load test results showed that the single pile bearing capacity was more than 4 times that of the same diameter mixing pile and more than 2 times that of the same diameter jet-grouting pile. The composite foundation bearing capacity can meet 500kPa. Moreover, it utilized solid waste, demonstrating its unique advantages.

[0065] Application Example 3: Pressure-grown jet grouting of steel pipe piles A foundation renovation project adopted a design using pressure-grown, jet-grouting concrete with steel pipe piles. The concrete was supplied by a mixing plant, and the 28-day test block strength was no less than 12 MPa. The pile length was 15m, the diameter of the pressure-grown piles was 400mm, the diameter of the jet-grouting piles was no less than 600mm, and the inserted steel pipes were 14m long with a diameter of 273mm. Static load test results showed that the single pile bearing capacity was more than 4 times that of a mixing pile of the same diameter, more than 2 times that of a jet-grouting pile of the same diameter, and more than 2 times that of a simple steel pipe pile. Furthermore, it utilized solid waste, demonstrating its unique advantages.

[0066] Application Example 4: Anti-buoyancy piles with steel strand cages inserted after pressure grouting and fixed shotcrete. A certain anti-buoyancy pile project was designed using pressure-grown, jet-sprayed concrete piles with reinforced steel strand cages. The concrete was supplied by a batching plant, with a concrete grade of C30. The pile length was 15m, the diameter of the pressure-grown piles was 400mm, and the diameter of the jet-sprayed piles was not less than 600mm. A 16m long reinforced steel strand cage with a diameter of 300mm was inserted. Static load test results showed that the single pile bearing capacity was twice that of a 400mm diameter reinforced concrete pile, and the project also utilized solid waste, demonstrating its unique advantages.

[0067] In the description of this invention, it should be understood that the terms "longitudinal", "lateral", "up", "down", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this invention, and are not intended to 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 this invention.

[0068] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A construction method for a long spiral pressure grouting and jet grouting composite foundation and pile foundation based on solid waste utilization, characterized in that, Includes the following steps: Construction preparation includes site preparation and equipment preparation. Among them, a long spiral drill with multiple grouting holes and air jet holes is selected, and the grouting holes are connected to the grouting equipment and the air jet holes are connected to the high-pressure air pump. Determine the pile location, including pile location positioning and marking; The target pile location is subjected to rotary grouting or fixed grouting to the design elevation. During rotary grouting, cement grout is sprayed out through the grouting holes and high-pressure air is sprayed out through the air grouting holes. After drilling the target pile position to the design elevation again, pressure grouting is carried out, and jet grouting or fixed jet grouting is carried out at the same time. The grout used for pressure grouting contains solid waste. After chiseling the pile head, a cushion layer is laid to form a composite foundation or pile foundation; After pressure grouting, a pile support structure is inserted into the pile hole.

2. The construction method for long spiral pressure grouting and jet grouting composite foundation and pile foundation based on solid waste utilization according to claim 1, characterized in that, The grout used for pressure grouting includes concrete or cement.

3. The construction method for long spiral pressure grouting and jet grouting composite foundation and pile foundation based on solid waste utilization according to claim 2, characterized in that, The concrete includes one or more of the following: cohesive soil, silt, sandy soil, and gravelly soil.

4. The construction method for long spiral pressure grouting and jet grouting composite foundation and pile foundation based on solid waste utilization according to claim 2, characterized in that, The fluidity of the concrete is 500–600 mm.

5. The construction method for long spiral pressure grouting and jet grouting composite foundation and pile foundation based on solid waste utilization according to claim 2, characterized in that, The concrete slump is 180–220 mm.

6. The construction method for long spiral pressure grouting and jet grouting composite foundation and pile foundation based on solid waste utilization according to claim 1, characterized in that, During rotary jet grouting, the slurry pressure is 20–25 MPa.

7. The construction method for long spiral pressure grouting and jet grouting composite foundation and pile foundation based on solid waste utilization according to claim 1, characterized in that, The pile support structure is a steel section, a steel cage, a steel strand cage, or a precast pile. When the grouting fluid is concrete, the steel cage and the steel strand cage are used as the pile support structure. When the grouting fluid is concrete, steel sections and precast piles are used as the pile support structure.

8. The construction method for long spiral pressure grouting and jet grouting composite foundation and pile foundation based on solid waste utilization according to claim 7, characterized in that, The precast piles are hollow pipe piles or square piles.

9. The construction method for long spiral pressure grouting and jet grouting composite foundation and pile foundation based on solid waste utilization according to claim 7, characterized in that, The steel section is a steel pipe.

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