High-pressure jet grouting pile construction technology
By applying total station control points and a dedicated sewage system, the problems of site accuracy and environmental protection in high-pressure jet grouting pile construction have been solved, ensuring pile quality and construction efficiency. It is suitable for projects such as bridge cutoff walls and building foundation reinforcement.
Patent Information
- Application Number
- CN202511982592.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-25
- Publication Date
- 2026-02-24
AI Technical Summary
The existing high-pressure jet grouting pile construction technology suffers from problems such as insufficient site and layout accuracy, poor environmental protection, and inadequate fault recovery, resulting in a decrease in the load-bearing capacity of the pile and environmental pollution.
The process of using total station control point burial stone marking and re-testing line was adopted. Underground obstacles were removed and the site was compacted. A dedicated sewage system was built to treat waste slurry. The drilling rig positioning and jet grouting process were standardized. The grouting time at the bottom of the pile was increased. Fault response measures were clarified to prevent equipment failure and slurry residue.
It improves the accuracy of site layout and setting out, ensures stable pile quality, reduces environmental pollution, enhances the standardization and efficiency of construction processes, reduces failure rate, and is suitable for engineering needs in multiple scenarios.
Smart Images
Figure CN121556444A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of foundation reinforcement technology, and in particular to a high-pressure jet grouting pile construction process. Background Technology
[0002] Cut-off walls are seepage-proof structures installed in the foundation or embankment of bridges to block groundwater seepage and control groundwater flow direction and water level. In existing technologies, cut-off walls can be constructed using high-pressure jet grouting piles.
[0003] The following problems exist in the existing high-pressure jet grouting pile construction technology: 1. Insufficient site preparation and layout accuracy: Traditional processes only address the basic requirement of leveling the ground, without specifying the depth to which underground obstacles should be removed. This makes it easy for the drilling rig to tilt after being positioned due to underground debris, and the verticality error of the borehole often exceeds 1%, affecting the overall bearing capacity of the pile. At the same time, pile layout often relies on simple tools such as ordinary tape measures, lacking the process of marking control points with stones using a total station and retesting the survey lines. The deviation of the pile hole center is generally greater than 50mm, which directly leads to substandard interlocking of adjacent piles and a decrease in the effectiveness of seepage prevention or foundation reinforcement. 2. Environmental protection and resource utilization issues are prominent: the existing process lacks a systematic treatment plan for construction waste slurry, and the methods of random discharge or simple sedimentation followed by direct disposal are mostly adopted, which pollutes the soil and water sources, fails to achieve water resource recycling, and is not connected to the site's wastewater treatment system, which does not meet the environmental protection requirements of modern engineering. 3. Insufficient fault remediation: The existing process does not clearly define the remedial measures after drilling rig shutdown and other failures, and does not emphasize the requirement to extend the grouting time in the key area at the bottom of the pile, resulting in weak strength at the bottom of the pile; the equipment is not thoroughly flushed after construction, and cement slurry remains in the grouting pipe and clumps, affecting the efficiency of the next construction. Summary of the Invention
[0004] The purpose of this invention is to provide a high-pressure jet grouting pile construction process that solves the problems of insufficient site and layout accuracy, poor environmental performance, and inadequate fault recovery in the existing traditional high-pressure jet grouting pile construction process.
[0005] To achieve the above objectives, the present invention provides a high-pressure jet grouting pile construction process, comprising the following steps: Step S1, Construction Preparation: Step S11, Site leveling: Before officially starting work, the construction site is cleared and leveled, and the various equipment is planned to achieve three connections and one level. Step S12, pile location layout: Before construction, surveying instruments are used to lay out and measure the points. Step S13, construct the sewage and mortar mixing system: Construct a sewage system to treat the waste slurry from the jet grouting pile construction process; Construct a mortar mixing system to prepare the grout required for jet grouting pile construction; Step S2, Drill Rig Positioning: After the drill rig is in place, it is leveled, centered, and its verticality is adjusted. Step S3, soil pilot hole: Before drilling, a test spray is carried out on the ground. After the drilling rig runs normally, the drilling rig starts pilot hole drilling through the core pipe. Step S4, Jet Grouting Machine in Place: After drilling to the designed depth, pull out the core tube and replace it with a grouting pipe and insert it to the predetermined depth, thus converting the drilling rig into a jet grouting machine; Step S5, Grouting Lifting: After the jet grouting pipe is inserted to the designed depth, the mud pump is turned on, and then the grout is sprayed from bottom to top while the mud is cleaned and discharged. Step S6, jet grouting machine relocation: When the jet grouting machine is raised to the designed pile top elevation, the jet grouting is stopped, the drill bit is raised out of the hole, and after flushing and cleaning, the jet grouting machine is relocated to complete the construction.
[0006] Preferably, in step S11, before formally commencing construction, obstacles within 2 meters below the ground level of the construction site are removed, and then leveled and compacted; at the same time, the locations of construction machinery, pipelines and power lines are reasonably arranged to achieve "three connections and one leveling", which refers to water supply, power supply, road access and site leveling.
[0007] Preferably, in step S12, before construction, the control points for jet grouting pile construction are determined using a total station and marked with embedded stones. After the retest line is qualified, the pile positions are laid out on the ground using a steel ruler and test line, and nailed with bamboo sticks, one stick per pile, with the center displacement deviation of the pile hole less than 50mm.
[0008] Preferably, in step S13, the waste slurry generated during the jet grouting pile construction is introduced into a sedimentation tank, and the clear water after sedimentation is discharged in a pollution-free manner according to the site conditions. The sedimented soil is transported away together when the foundation pit is excavated, and the sedimentation and sewage discharge are uniformly incorporated into the site's sewage treatment system. The mortar mixing system includes mortar mixing equipment, mortar storage equipment, and mortar conveying equipment. The mortar mixing system is located near the cement for easy operation.
[0009] Preferably, in step S2, after the drilling rig is in place, it is leveled and centered, and the verticality of the pile driver is adjusted so that the drill rod is consistent with the pile position with a deviation within 10mm and the verticality error of the borehole is less than 0.5%. Before drilling, the air compressor and mud pump should be tested to ensure that the equipment is operating normally. The length of the drill rod is checked, and the depth line is marked next to the drilling tower with red paint. The bottom elevation of the hole meets the design depth. In step S3, the number of drill rod sections is recorded in detail during the drilling process to maintain the accuracy of the drilling depth.
[0010] Preferably, in step S4, during the insertion of the grouting pipe, water is injected through a high-pressure water nozzle while the pipe is inserted, with a water pressure ≤1 MPa, and the high-pressure water nozzle is wrapped with plastic sheeting.
[0011] Preferably, in step S5, during spraying, the predetermined spraying pressure is reached first, and the spray nozzle is gradually raised after spraying; when the nozzle sinks to the designed depth, it is rotated in the original position, and the spray nozzle is raised again after the slurry is flowing out of the orifice normally.
[0012] Preferably, the rotation and lifting of the drill rod are continuous and uninterrupted. If the drilling rig malfunctions, the lifting and rotation of the drill rod are stopped, and the malfunction is immediately repaired and eliminated. The time for grouting of the drill rod is increased within 1.0m of the bottom of the pile.
[0013] Preferably, during the jet grouting lifting process, the jet grouting parameters are adjusted according to different soil layers.
[0014] Preferably, in step S6, after the spraying construction is completed, the grouting rod and equipment are cleaned. The cleaning method is to replace the grout with water and spray it on the ground to remove the grout from the mud pump, grouting pipe and hose, and then move the jet grouting machine.
[0015] Therefore, the high-pressure jet grouting pile construction process described above has the following beneficial effects: 1. Controllable site and layout accuracy: Clearly require the removal and compaction of obstacles within 2 meters below the ground. Combine the process of total station control point stone marking + retest line to control the displacement deviation of the pile hole center, the deviation between the drill rod and the pile position, and the verticality error of the drill hole, thereby improving accuracy. 2. Stable and qualified pile quality: Through forced test spraying, equipment debugging and drill rod length marking, the drilling depth is ensured to meet the design requirements; the jet grouting parameters are adjusted for different soil layers, and the spraying time is increased in the 1.0m range at the bottom of the pile to effectively avoid pile breakage and increase the compressive strength of the pile. 3. This invention constructs a dedicated sewage system to introduce construction waste slurry into a sedimentation tank for treatment. After sedimentation, the clear water is discharged in a pollution-free manner according to site conditions, and the sedimented soil is uniformly transported away during the excavation of the foundation pit. It is also connected to the site's sewage treatment system, which solves the pollution problem of indiscriminate discharge of waste slurry in traditional processes. At the same time, the mortar mixing system is set up near the cement to reduce slurry transportation losses and take into account both environmental protection and resource utilization efficiency. 4. Standardize the construction process to improve efficiency and reliability: Standardize the entire process of drilling rig positioning, soil layer pre-hole drilling, jet grouting machine conversion, grouting lifting, and equipment relocation; clarify the anti-clogging measures such as inserting pipe while spraying water and wrapping the nozzle with plastic sheeting during pipe insertion to reduce the incidence of construction failures. 5. Clear Fault Response: In case of drilling rig shutdown, lifting and rotation must be stopped immediately. After inspection, spraying should be carried out in key areas at the bottom of the pile to avoid pile breakage. Grout leakage should be classified and handled to reduce grout waste and ensure that the pile diameter meets the standard. After construction, grout should be replaced with water and the ground should be sprayed to flush the grouting pipe and mud pump to avoid residual cement grout clumping, extend equipment life, and reduce the failure rate of subsequent construction. 6. Wide applicability, meeting the needs of multiple engineering scenarios: This technology is not only applicable to bridge cutoff walls, but can also be extended to different scenarios such as building foundation reinforcement and roadbed treatment; the core parameters can be adjusted according to design requirements to adapt to different geological conditions and engineering standards, making it highly practical.
[0016] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description
[0017] Figure 1 This is a process flow diagram of an embodiment of the high-pressure jet grouting pile construction process of the present invention. Detailed Implementation
[0018] To make the objectives, technical solutions, and advantages disclosed in the embodiments of the present invention clearer, the embodiments of the present invention will be further described in detail below with reference to the accompanying drawings and examples. It should be understood that the specific embodiments described herein are only used to explain the embodiments of the present invention and are not intended to limit the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments in this application without creative effort are within the scope of protection of this application. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout.
[0019] It should be noted that the terms “comprising” and “having”, and any variations thereof, are intended to cover non-exclusive inclusion, such as a process, method, system, product, or server that includes a series of steps or units, not necessarily limited to those steps or units that are explicitly listed, but may include other steps or units that are not explicitly listed or that are inherent to such processes, methods, products, or devices.
[0020] Similar labels and letters in the following figures indicate similar items; therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.
[0021] In the description of this invention, it should be noted that the terms "upper," "lower," "inner," "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship in which the product of this invention is usually placed when in use. 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.
[0022] In the description of this invention, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set," "install," and "connect" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.
[0023] Example: The present invention takes the construction of a bridge cutoff wall as an example. The cutoff wall adopts high-pressure jet grouting, with the top elevation of the grouting being 66.9m and the bottom elevation being 46.89~63.58m. The center line of the cutoff wall is 1.5m away from the water-facing side of the embankment.
[0024] The high-pressure jet grouting wall is constructed using a double-pipe method, with a total seepage interception length of 2380m. The jet grouting piles have a diameter of 800mm, a tentative pile spacing of 500mm, a 300mm overlap between adjacent piles, and a wall thickness of no less than 600mm. Each borehole penetrates at least 500mm into the rock (strongly weathered andesite). The wall's permeability coefficient is no greater than 1×10⁻⁵ cm / s, and its compressive strength is no less than 3 MPa. The double-pipe grouting method of high-pressure jet grouting piles utilizes high-pressure equipment to transform cement grout into a high-pressure jet, which is ejected from nozzles to impact and break up the soil. When the dynamic pressure of the high-energy, high-velocity, and pulsating jet exceeds the structural strength of the soil, soil particles are stripped from the soil. Some fine particles emerge with the grout. The remaining soil particles, under the impact force, centrifugal force, and gravity of the jet, are mixed with the grout and rearranged in a regular manner according to a certain grout-to-soil ratio and mass. After the grout solidifies, it forms a solidified body within the soil. It is mainly used to reinforce the foundation, improve the shear strength of the foundation, and improve soil deformation.
[0025] Technical briefings on the drawings were conducted strictly in accordance with the design requirements and relevant specifications. Construction process parameters are shown in Table 1.
[0026] Table 1. Reference Table of Main Technical Parameters for Jet Grouting Pile Construction
[0027] Slurry volume calculation: The slurry volume is calculated based on the slurry volume injected per unit time and the injection duration. The calculation formula is as follows: ; In the formula, —Pulp volume (m³) 3 ); —Spray length (m); —Thickening volume per unit time (m³) 3 / min); —Loss coefficient, typically 0.1 to 0.2; —Increase speed (m / min).
[0028] The required amount of shotcrete is calculated based on the test pile parameters to determine the amount of cement to be used.
[0029] like Figure 1 As shown, the construction process is as follows: Step S1, Construction Preparation: Step S11, Leveling the site: Before officially starting construction, remove obstacles within 2 meters below the ground level of the construction site, and then level and compact the surface. At the same time, arrange the positions of construction machinery, pipelines and power lines reasonably to ensure that the construction site has access to water, electricity, roads and a level surface.
[0030] Step S12, pile location layout: Before construction, a total station was used to determine the control points for jet grouting pile construction and to mark them with stones. After the test line was verified to be qualified, the pile positions were laid out on the ground with a steel ruler and test line, and nailed with bamboo sticks. One stick was used for each pile to ensure that the center displacement deviation of the pile hole was less than 50mm.
[0031] Step S13, construct the sewage and mortar mixing system: During the jet grouting pile construction process, 10% to 20% of the grout will be returned. The waste grout will be introduced into a sedimentation tank, and the clear water after sedimentation can be discharged in a pollution-free manner depending on site conditions. The settled soil will be removed during the excavation of the foundation pit. Sedimentation and wastewater discharge will be incorporated into the site's overall wastewater treatment system.
[0032] The mortar mixing system is mainly located near the cement for easy operation and consists of mortar mixing equipment, mortar storage equipment, and mortar conveying equipment.
[0033] Construction water and electricity are supplied from the local water supply network and power grid.
[0034] Step S2, drilling rig in place: After the drilling rig is in place, it should be leveled and centered, and the verticality of the pile driver should be adjusted to ensure that the drill rod is consistent with the pile position, with a deviation within 10mm and a drilling verticality error of less than 0.5%. Before drilling, the air compressor and mud pump should be tested to ensure that the equipment is operating normally. The length of the drill rod should be checked, and the depth line should be marked next to the drilling tower with red paint to ensure that the bottom elevation of the hole meets the design depth.
[0035] Step S3, soil pre-hole drilling: Before drilling begins, a test run should be conducted on the ground. After the drilling machinery has been tested and found to be running normally, pilot drilling can commence. During the drilling process, the number of drill rod sections must be recorded in detail to ensure the accuracy of the drilling depth.
[0036] Step S4, the rotary jetting machine is in place: After drilling to the designed depth, pull out the core tube and replace it with a jet grouting pipe inserted to the predetermined depth. During the insertion process, to prevent mud and sand from clogging the nozzle, water should be injected while inserting the pipe. The water pressure should not exceed 1 MPa to avoid excessive pressure that could puncture the borehole wall. The high-pressure water nozzle should be wrapped with plastic sheeting to prevent mud from entering the pipe.
[0037] Step S5, Grouting and Lifting: After the jet grouting pipe is inserted to the designed depth, the mud pump is turned on, and then the grouting is performed from bottom to top, while simultaneously cleaning and discharging the mud. During jet grouting, the predetermined jet pressure should be reached first, and grout should be sprayed before gradually raising the jet grouting pipe to prevent it from twisting and breaking. To ensure the quality of the pile bottom, when the nozzle sinks to the designed depth, it should be rotated in the original position for about 10 seconds until grout is flowing normally from the borehole opening before jet grouting and raising. The rotation and raising of the drill rod should be continuous and uninterrupted. If the drilling rig malfunctions, the raising and rotation of the drill rod should be stopped to prevent pile breakage, and the fault should be repaired and rectified immediately. To improve the quality of the pile bottom, the jet grouting time should be appropriately increased within 1.0m of the pile bottom. During the jet grouting and raising process, the jet grouting parameters can be adjusted according to different soil layers.
[0038] Step S5, repositioning of the rotary jet sprayer: When the jet grouting reaches the designed pile top elevation, stop the jet grouting and raise the drill bit out of the borehole. After the jet grouting is completed, the grouting pipes and other equipment should be thoroughly cleaned, and no cement slurry should remain inside the pipes or the machine. Usually, the slurry is replaced with water and sprayed on the ground to completely drain the slurry from the mud pump, grouting pipes, and hoses before moving the drilling rig.
[0039] The entire construction process should be primarily carried out using jet grouting machines, with other personnel and equipment working closely together and obeying commands and instructions. Repeat the above steps until the entire cutoff wall is completed.
[0040] Jet grouting pile construction quality standards: 1) Guarantee Project The cement used for jet grouting piles is P.O42.5 ordinary Portland cement. The cement has been tested and found to meet the inspection standards and design requirements, and the water-cement ratio of the cement slurry meets the design requirements.
[0041] 2) Basic Projects The depth, diameter, verticality, and strength of the high-pressure jet grouting piles meet the design requirements.
[0042] Test method: After the pile body reaches the design strength, the diameter, verticality and uniformity of the pile body are tested by mechanical excavation on both sides of the jet grouting pile from the top of the pile to 3-4 meters below the ground.
[0043] 3) Allowable deviation The permissible deviations and inspection methods for jet grouting piles shall comply with the provisions of Table 2.
[0044] Table 2. Allowable Deviations and Inspection Methods for Jet Grouting Piles
[0045] Construction Precautions: 1) When constructing jet grouting piles, a skip-driving method should be adopted, and the construction spacing should be reasonably arranged. The construction interval between two adjacent piles should not be less than 48 hours, and the spacing should not be less than 4 to 6 meters.
[0046] 2) After the drilling rig is in place, it should be horizontally and vertically corrected. The drill rod should match the pile position, and the deviation should be controlled within 10mm.
[0047] 3) Before the construction of jet grouting piles, the jet grouting construction parameters must be determined: jet grouting speed, lifting speed, nozzle diameter, etc.
[0048] 4) After the jet grouting pipe reaches the predetermined depth, a high-pressure water jetting test should be conducted. Grout can only be sprayed after the test is passed. After the predetermined pressure and discharge volume are reached, the jet grouting pipe should be gradually raised. For deep jet grouting, grout should be sprayed first, followed by jet grouting and raising, to prevent the grouting pipe from twisting and breaking.
[0049] 5) Treatment of grout leakage by jet grouting Grouting: During jet grouting, the high-pressure jet stream cuts through the soil in the foundation, and the reinforced area is a cylinder with a radius equal to the jetting distance plus the length of the seepage portion. Some fine soil particles are replaced by the jet grout and carried to the ground with the liquid flow (commonly known as grouting), while the rest are mixed with the grout.
[0050] During the jet grouting process, a certain amount of soil particles often emerge from the ground along with some grout through the injection pipe. By observing the grout emergence, it is normal for the amount of grout emergence to be less than 20% of the injection volume. If it exceeds 20% or there is no grout emergence at all, the cause should be investigated and corresponding measures should be taken.
[0051] If large voids in the formation prevent grout from seeping out, an appropriate amount of quick-setting agent can be added to the grout to allow it to solidify within a certain range. Alternatively, the grouting volume can be increased in void areas to fill the voids before continuing normal jet grouting. Excessive grout seepage is caused by a mismatch between the effective spraying range and the grouting volume. Measures such as increasing the spraying pressure, appropriately reducing the nozzle diameter, and accelerating the lifting and jetting speed can reduce grout seepage.
[0052] 6) During the insertion and spraying process, care must be taken to prevent the nozzle from becoming clogged. The pressure and flow rate must meet the design values; otherwise, the pipe must be removed and cleaned before re-inserting and spraying. During the insertion process, to prevent silt blockage, water can be sprayed while inserting the pipe to avoid silt blockage.
[0053] 7) The cement selected should be tested and sieved. Its fineness should be such that the residue on a standard sieve (0.08mm aperture) is no more than 15%, and the slurry should not be stirred for more than 4 hours.
[0054] 8) The rotation and lifting of the drill rod must be continuous and uninterrupted. When disassembling the drill rod, maintain an overlap length of at least 0.3m to prevent the jet grouting solidified body from disintegrating. If mechanical failure occurs midway, lifting and jet grouting should be stopped to prevent pile breakage. The fault should be inspected and rectified immediately. To improve the quality of the jet grouting pile, measures should be taken for a longer duration within 0.5m of the pile bottom.
[0055] 9) After the jet grouting pile construction is completed, heavy objects should not be piled up on site to prevent deformation of the jet grouting pile.
[0056] 10) The construction quality of jet grouting piles is crucial to ensuring the bearing capacity of the foundation during construction. Jet grouting pile construction should be carried out strictly in accordance with construction specifications. The key points of construction are as follows: ① During construction, the vertical deviation of the borehole should not exceed 1 / 150, and the pile position deviation should not be greater than 50mm.
[0057] ② The injection pressure and lifting speed have a significant impact on the pile diameter and should be adjusted according to the pile diameter.
[0058] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the technical solutions of the present invention, and these modifications or equivalent substitutions cannot cause the modified technical solutions to deviate from the spirit and scope of the technical solutions of the present invention.
Claims
1. A high-pressure jet grouting pile construction process, characterized in that, Includes the following steps: Step S1, Construction Preparation: Step S11, Site leveling: Before officially starting work, the construction site is cleared and leveled, and the various equipment is planned to achieve three connections and one leveling. Step S12, pile location layout: Before construction, surveying instruments are used to lay out and measure the points. Step S13, construct the sewage and mortar mixing system: Construct a sewage system to treat the waste slurry from the jet grouting pile construction process; Construct a mortar mixing system to prepare the grout required for jet grouting pile construction; Step S2, Drill Rig Positioning: After the drill rig is in place, it is leveled, centered, and its verticality is adjusted. Step S3, soil pilot hole: Before drilling, a test spray is carried out on the ground. After the drilling rig runs normally, the drilling rig starts pilot hole drilling through the core pipe. Step S4, Jet Grouting Machine in Place: After drilling to the designed depth, pull out the core tube and replace it with a grouting pipe inserted to the predetermined depth, thus converting the drilling rig into a jet grouting machine; Step S5, Grouting Lifting: After the jet grouting pipe is inserted to the designed depth, the mud pump is turned on, and then the grout is sprayed from bottom to top while the mud is cleaned and discharged. Step S6, jet grouting machine relocation: When the jet grouting machine is raised to the designed pile top elevation, the jet grouting is stopped, the drill bit is raised out of the hole, and after flushing and cleaning, the jet grouting machine is relocated to complete the construction.
2. The high-pressure jet grouting pile construction process according to claim 1, characterized in that: In step S11, before officially starting construction, obstacles within 2 meters below the ground level of the construction site are removed, and then leveled and compacted; at the same time, the positions of construction machinery, pipelines and power lines are reasonably arranged to achieve "three connections and one leveling", which means water supply, power supply, road access and site leveling.
3. The high-pressure jet grouting pile construction process according to claim 1, characterized in that: In step S12, before construction, the control points for jet grouting pile construction are determined using a total station and marked with embedded stones. After the retest line is qualified, the pile positions are laid out on the ground using a steel ruler and measuring line, and nailed with bamboo sticks. One stick is used for each pile, and the deviation of the center displacement of the pile hole is less than 50mm.
4. The high-pressure jet grouting pile construction process according to claim 1, characterized in that: In step S13, the waste slurry generated during the jet grouting pile construction is introduced into a sedimentation tank. The clear water after sedimentation is discharged in a pollution-free manner according to the site conditions. The sedimented soil is transported away together when the foundation pit is excavated. The sedimentation and sewage discharge are uniformly incorporated into the site's sewage treatment system. The mortar mixing system includes mortar mixing equipment, mortar storage equipment, and mortar conveying equipment. The mortar mixing system is located near the cement for easy operation.
5. The high-pressure jet grouting pile construction process according to claim 1, characterized in that: In step S2, after the drilling rig is in place, it is leveled and centered, and the verticality of the pile driver is adjusted so that the drill rod is consistent with the pile position with a deviation within 10mm and the verticality error of the borehole is less than 0.5%. Before drilling, the air compressor and mud pump should be tested to ensure that the equipment is operating normally. The length of the drill rod is checked, and the depth line is marked next to the drilling tower with red paint. The bottom elevation of the hole meets the design depth. In step S3, the number of drill rod sections is recorded in detail during the drilling process to maintain the accuracy of the drilling depth.
6. The high-pressure jet grouting pile construction process according to claim 1, characterized in that: In step S4, during the insertion of the grouting pipe, water is injected through a high-pressure water nozzle while the pipe is inserted, with a water pressure ≤1 MPa. The high-pressure water nozzle is wrapped with plastic sheeting.
7. The high-pressure jet grouting pile construction process according to claim 1, characterized in that: In step S5, during spraying, the predetermined spraying pressure is reached first, and the spray nozzle is gradually raised after spraying. When the nozzle sinks to the designed depth, it is rotated in the original position, and the spray nozzle is raised again after the slurry is flowing out of the orifice normally.
8. The high-pressure jet grouting pile construction process according to claim 7, characterized in that: The rotation and lifting of the drill rod are continuous and uninterrupted. If the drilling rig malfunctions, the lifting and rotation of the drill rod are stopped, and the malfunction is immediately repaired and eliminated. The time for grouting of the drill rod is increased within 1.0m of the bottom of the pile.
9. The high-pressure jet grouting pile construction process according to claim 8, characterized in that: During the jet grouting process, the jet grouting parameters are adjusted according to different soil layers.
10. The high-pressure jet grouting pile construction process according to claim 1, characterized in that: In step S6, after the spraying construction is completed, the grouting rod and equipment are cleaned. The cleaning method is to replace the grout with water and spray it on the ground to remove the grout from the mud pump, grouting pipe and hose. Then the jet grouting machine is moved.