Pipe jacking structure assisted by mud jacket forming and pipe jacking construction method

Abstract

This invention relates to the field of pipe jacking engineering, specifically to a pipe jacking structure and a method for assisting in the formation of a slurry sleeve. The pipe jacking is formed by splicing at least two sets of pipe sections together with bearings. Drag-reducing slurry is injected into the gap between the pipe sections and the ground to form a slurry sleeve. At least one cross-section of each pipe section serves as a grouting section, and grouting holes are arranged in the plane of the grouting section, distributed circumferentially within the grouting section. Multiple sets of grouting holes are arranged along the axial direction of the pipe section on the wall of at least one set of pipe sections. Pipe sections with grouting holes are spaced apart along the length of the pipe jacking. Openings on the inner wall of the pipe sections, including the grouting holes and grouting holes, serve as inlets, and openings on the outer wall of the pipe sections serve as outlets. This invention provides a pipe jacking structure and a method for assisting in the formation of a slurry sleeve.

Description

Technical Field

[0001] This invention relates to the field of pipe jacking engineering, specifically to a pipe jacking structure and a construction method for forming a mud sleeve. Background Technology

[0002] Pipe jacking, a trenchless pipeline laying technology, has been widely applied in recent years in projects such as urban subway entrances and exits, integrated utility tunnels, and underground commercial streets. During pipe jacking construction, it is crucial to overcome the significant frictional resistance from the surrounding soil, particularly in long-distance and large-diameter pipe jacking projects. To reduce this frictional resistance, drag-reducing slurry is typically injected into the 2-5cm annular space between the pipe and the soil. This slurry converts the dry friction between the pipe and the soil into liquid friction, thus reducing frictional resistance. Furthermore, it fills the voids between the pipe and the soil, reducing soil deformation and supporting the ground. If the injected drag-reducing slurry can quickly form a relatively complete drag-reducing slurry sleeve around the pipe, it can increase the single-stage jacking length, reduce the amount of slurry used in intermittent sections, and increase the distance between the working shaft and the receiving shaft, thereby reducing the number of working and receiving shafts and lowering project costs. If the drag-reducing mud fails to form a good mud sleeve, there will be insufficient support, and the soil will collapse onto the outer wall of the pipe, turning sliding friction into dry friction. At this point, the frictional resistance of the entire pipe section will increase significantly. Therefore, for pipe jacking projects, the ability to quickly form a complete and closed drag-reducing mud sleeve plays a decisive role in the success or failure of the project.

[0003] However, current pipe jacking construction methods often involve setting up a separate grouting system behind the jacking head. This method's effectiveness is limited to the local area traversed by the jacking head. As the jacking distance increases, subsequent pipe sections passing through this area experience continuous seepage and consolidation of the grout within the annulus, causing the initial grout sleeve to gradually thin or even cease. Furthermore, due to the addition of a separate grouting system, its size is typically larger than the outer diameter of the jacking pipe. This process actively scrapes the soil or compresses the strata, directly increasing soil displacement resistance and disrupting the originally stable borehole wall morphology. Therefore, these issues urgently need to be addressed. Summary of the Invention

[0004] To avoid and overcome the technical problems existing in the prior art, this invention provides a jacking pipe structure and a construction method for assisting in the formation of the mud sleeve. This invention eliminates the need for a separate grouting device at the jacking head, ensuring continuous and stable formation of the mud sleeve without additional friction during construction.

[0005] To achieve the above objectives, the present invention provides the following technical solution: A pipe jacking structure for assisting in the formation of a mud sleeve, wherein the pipe jacking is formed by splicing at least two sets of pipe sections with bearings; drag-reducing mud is injected into the gap between the pipe sections and the formation to form a mud sleeve; At least one cross section of each pipe section serves as a grouting section, and grouting holes are arranged in the plane of the grouting section. The grouting holes are distributed along the circumference of the pipe section within the grouting section. On the pipe wall of at least one set of pipe sections, multiple sets of grouting holes are arranged along the axial direction of the pipe section itself. Pipe sections with grouting holes are arranged at intervals along the length of the jacking pipe. The openings of the grouting holes and grouting holes located on the inner wall of the pipe section serve as inlets, and the openings of the grouting holes and grouting holes located on the outer wall of the pipe section serve as outlets.

[0006] As a further aspect of the present invention: each pipe section is pre-embedded with a pre-embedded grouting pipe assembly for grouting and / or grouting repair. The pre-embedded grouting pipe assembly includes a main flow port as the inlet and various branch ports connected to the main flow port. The inlet of the main flow port is flush with the inner wall of the pipe section to serve as the inlet of the grouting hole or the grouting repair hole. The outlet of the branch ports is flush with the outer wall of the pipe section to serve as the outlet of the grouting hole or the grouting repair hole. The branch ports are arranged at equal intervals along a straight line.

[0007] As a further aspect of the present invention: the inner wall of the main flow port of the pre-embedded grouting pipe assembly is threaded to connect a detachable plug to seal the main flow port; the pre-embedded grouting pipe assembly has 7 to 10 sets of branch ports, and each branch port has a screen hole at its outlet; the diameter of the branch port is 15 to 30 mm, and the distance between adjacent branch ports is 30 to 80 cm.

[0008] As a further aspect of the present invention: each of the pipe sections is provided with a pre-embedded grouting pipe assembly configured for grouting, and the pipe sections with grouting holes are arranged at intervals between each pipe section along the length direction of the jacking pipe; the pre-embedded grouting pipe assembly for grouting passes through the corresponding grouting section, and its extension direction is perpendicular to the grouting section.

[0009] As a further aspect of the present invention, it also includes a grouting system disposed on the inner wall of the pipe section. The grouting system includes branch grouting pipes arranged circumferentially along the pipe section and communicating with each grouting hole, and a main grouting pipe arranged axially along the pipe section and communicating with each branch grouting pipe. A grouting replenishment pipe is also disposed axially inside the pipe section and is communicating with the main outlet of a pre-embedded grouting pipe assembly used for grouting.

[0010] As a further embodiment of the present invention: the main grouting pipe and / or the branch grouting pipe are fixed to the inner wall of the pipe section by any one of the following methods: snap fastener, pipe clamp, or snap-fit; the main grouting pipe is connected to the branch grouting pipe through an N-type fitting, and the grouting repair pipe and / or the branch grouting pipe are connected to the main outlet of the corresponding pre-embedded grouting pipe assembly through a bolt joint.

[0011] As a further aspect of the present invention: each pipe section has a set of grouting sections in the middle of the pipe section, with the number of branch ports of the pre-embedded grouting pipe assembly being... mGroup, the center distance between adjacent branch outlets is d The grouting diffusion radius of each branch port is R : ; in, Q The total grouting flow rate for a single pre-embedded grouting pipe assembly; t This refers to the duration of grouting. b The thickness is affected by the amount of mud injected in a single injection; n This represents the formation porosity.

[0012] As a further aspect of the present invention: using the target diffusion radius R Based on the design, the grouting pressure corresponding to the main inlet. p 0 is calculated using the following formula: ; in, p R For the slurry to diffuse to a radius R The remaining pressure at the location; μ To reduce the dynamic viscosity of the mud; K The horizontal permeability coefficient of the formation; r 0 represents the radius of a single branch outlet; β This is the correction factor for the superposition of intergroup seepage.

[0013] A method for forming a mud sleeve, using a jacking structure to assist in forming the mud sleeve, specifically includes the following steps: S1. When casting the pipe section, pre-embed the pre-embedded grouting pipe assembly at the set position of the pipe section. After splicing the cast pipe sections in sequence, connect each pre-embedded grouting pipe assembly to the grouting system to complete the connection of the entire pipeline and the sealing test. S2. Determine the process parameters for the grouting process, including the grouting working pressure, grouting flow rate, replenishment working pressure, replenishment flow rate, grouting diffusion radius R, grouting volume per pipe section, and number of pipe section intervals for replenishment. S3. Before starting the jacking construction, the principle of grouting before jacking shall be followed. Grouting shall be carried out through the grouting holes into the gap between the outer wall of the pipe section and the stratum until a complete closed annular mud sleeve is formed around the outer periphery of the first pipe section. S4. After the mud sleeve is formed and stabilized, start the jacking. Maintain continuous grouting throughout the jacking process. Dynamically adjust the grouting pressure and flow rate according to the real-time jacking speed to maintain the uniformity and continuity of the mud sleeve. S5. During the grouting operation, grout is added to the grouting holes to improve the uniformity and continuity of the mud sleeve. S6. After the entire section of jacking construction is completed, the grouting and replenishment grouting are closed in sequence, and the main outlets of all pre-embedded grouting pipe components are sealed with a plugging device to maintain the long-term sealing and stability of the mud sleeve.

[0014] As a further aspect of the present invention: in S5, the grouting operation has the following two working modes; Conventional grouting mode: When the jacking reaches the pipe section containing grouting holes, the grouting pump is activated to perform fixed-point grouting through the grouting pipe to fill the gaps caused by mud seepage and formation shrinkage. After the grouting reaches the standard, the grouting pipe is shut off. Dynamic grouting mode: Real-time monitoring of jacking resistance and cross-sectional mud pressure. When resistance suddenly increases or local mud pressure falls below the threshold, targeted grouting is performed at the abnormal pipe section until the monitoring indicators return to the normal range.

[0015] Compared with the prior art, the beneficial effects of the present invention are: 1. This invention forms a three-dimensional grouting system that combines cross-sectional grouting with axial grouting by setting at least one set of grouting sections on the pipe section and configuring grouting holes on each section, while simultaneously setting grouting replenishment holes along the axial direction; combined with the cooperation of the main outlet of the pre-embedded grouting pipe assembly and multiple branch outlets, the grout can be squeezed out from multiple points on the outer wall of the pipe section simultaneously and uniformly, effectively covering the entire circumferential and axial range, ensuring that a complete closed annular grout sleeve is formed on the outer periphery of each pipe section; the overall grouting device is integrated on the pipe section, avoiding the increase of friction during construction by the external grouting system.

[0016] 2. This invention, by arranging pipe sections with grouting holes at intervals and setting up independent grouting pipelines, can perform fixed-point grouting during conventional jacking and dynamic grouting based on real-time monitoring data. The dual-mode switching ensures the uniform and continuous mud sleeve throughout the long-distance jacking process, significantly reducing jacking resistance fluctuations. At the same time, through calculation, the grouting pressure is determined based on the grouting diffusion radius, and the specific grouting process parameters are accurately calculated in combination with the formation conditions, improving the controllability of mud sleeve formation.

[0017] 3. The pre-embedded grouting pipe assembly of the present invention is pre-embedded during the casting of the pipe section. The main outlet is flush with the inner wall of the pipe section, and the branch outlet is flush with the outer wall. The main outlet is machined with a threaded connection and a detachable plug. On site, it is only necessary to connect the grouting system to each main outlet, which is quick to install. After the jacking is completed, the plug is used to seal all the main outlets, which effectively prevents the long-term loss of mud and ensures the long-term sealing stability of the mud sleeve.

[0018] 4. The present invention provides a main grouting pipe and branch grouting pipes along the inner wall of the pipe section. The branch pipes are arranged circumferentially and connected to each grouting hole. The main pipe is connected to each branch pipe axially. An independent grouting pipe is also provided. The pipeline is fixed by means of buckles, pipe clamps, etc., which is convenient for disassembly and maintenance and can adapt to different pipe diameters and grouting requirements. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the structure of the present invention.

[0020] Figure 2 This is a cross-sectional view of the present invention.

[0021] Figure 3 This is a schematic diagram of the pre-embedded grouting pipe assembly in this invention.

[0022] Figure 4 This is a schematic diagram showing the connection relationship between the odd-numbered pipe sections and the slurry delivery system in this invention.

[0023] Figure 5 This is a schematic diagram showing the connection relationship between the even-numbered pipe sections and the slurry delivery system in this invention.

[0024] Figure 6 This is a simplified schematic diagram of the construction process of the present invention.

[0025] In the picture: 1. Pipe section; 11. Grouting hole; 12. Grouting repair hole; 13. Grouting section; 2. Drag-reducing mud; 3. Formation; 4. Grouting system; 41. Main grouting pipe; 42. Branch grouting pipe; 43. Repair grouting pipe; 5. Pre-embedded grouting pipe assembly; 51. Main flow port; 52. Diversion port; 53. Sealing device. Detailed Implementation

[0026] 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.

[0027] Please see Figures 1-6In this embodiment of the invention, a jacking pipe structure and a method for forming a mud sleeve are disclosed. The jacking pipe is formed by splicing at least multiple sets of pipe sections 1 together with bearings, and each pipe section 1 is connected end to end to form a complete jacking pipe. Drag-reducing mud 2 is injected into the gap between the pipe section 1 and the stratum 3. The drag-reducing mud 2 forms a mud sleeve between the outer wall of the pipe section 1 and the stratum 3 to reduce the frictional resistance between the pipe section 1 and the stratum 3 during the jacking process. The cross-sectional shape of the pipe section 1 is not limited and can be rectangular, circular, or other irregular shapes. In this embodiment, a rectangular cross-section is used.

[0028] At least one cross section of each pipe section 1 is a grouting section 13. In this embodiment, each pipe section 1 preferably has a set of grouting sections 13 in the middle. The grouting sections 13 are used to indicate the distribution positions of the grouting holes 11. Grouting holes 11 are arranged along the grouting sections 13 on the pipe section 1, and the grouting holes 11 penetrate the pipe wall of the pipe section 1. The opening of the grouting hole 11 on the inner wall of the pipe section 1 serves as the inlet, and the opening of the grouting hole 11 on the outer wall of the pipe section 1 serves as the outlet. After the drag-reducing mud 2 is injected from the inner wall inlet, it is discharged from the outer wall outlet through the grouting hole 11 into the gap between the pipe section 1 and the formation 3.

[0029] Pipe section 1 is divided into odd-numbered and even-numbered groups along its arrangement direction. Each even-numbered group of pipe sections 1 has a grouting hole 12 along its axial direction. The grouting hole 12 penetrates the pipe wall of the pipe section 1. The opening on the inner wall of the grouting hole 12 serves as the inlet, and the opening on the outer wall serves as the outlet. The grouting hole 12 is used to replenish drag-reducing mud 2 to the mud sleeve during pipe jacking to maintain the integrity of the mud sleeve. Based on this, and influenced by actual pipe jacking projects, the grouting hole 12 can be installed on one of the groups of pipe sections 1 after an interval of 5 to 10 groups, balancing the need for long-distance grouting with project economy.

[0030] To facilitate the fabrication of grouting holes 11 and grouting repair holes 12, each pipe section 1 is pre-embedded with a pre-embedded grouting pipe assembly 5 for grouting or grouting repair during fabrication. The height of this assembly corresponds to the thickness of the pipe section 1. The pre-embedded grouting pipe assembly 5 includes a main flow port 51 as the inlet and various branch ports 52 connected to the main flow port 51. The inlet of the main flow port 51 is flush with the inner wall of the pipe section 1, serving as the inlet for the grouting hole 11 or grouting repair hole 12. The outlet of the branch ports 52 is flush with the outer wall of the pipe section 1, serving as the outlet for the grouting hole 11 or grouting repair hole 12. The branch ports 52 are evenly spaced along a straight line, allowing the drag-reducing mud 2 to be evenly discharged from multiple locations on the outer wall of the pipe section 1, thereby forming a uniform mud sleeve between the outer wall of the pipe section 1 and the formation 3. The inner wall of the main flow port 51 of the pre-embedded grouting pipe assembly 5 is threaded, allowing for detachable connection of a plugging device 53 to seal the main flow port 51. When the pre-embedded grouting pipe assembly 5 is not in use, the main outlet 51 can be sealed by the plug 53 to prevent the drag-reducing slurry 2 from leaking out. The pre-embedded grouting pipe assembly 5 has 7 to 10 sets of branch outlets 52, each with a sieve at its outlet. The diameter of the branch outlets 52 is 15 to 30 mm, and the spacing between adjacent branch outlets 52 is 30 to 80 cm. A larger time interval is used for soft soil layers, and a smaller time interval is used for hard soil layers. The axis of each main outlet 51 of the pre-embedded grouting pipe assembly 5 used for grouting is located on the grouting section 13.

[0031] In this embodiment, each pipe section 1 has 6 to 10 sets of pre-embedded grouting pipe assemblies 5 for grouting, arranged symmetrically on the upper, lower, left, and right sides. 2 to 3 sets of pre-embedded grouting pipe assemblies 5 are arranged on the upper and lower parts of pipe section 1, and 1 to 2 sets of pre-embedded grouting pipe assemblies 5 are arranged on the sidewall of the jacking pipe section. On even-numbered pipe sections 1, 1 to 2 sets of pre-embedded grouting pipe assemblies 5 for grouting are typically installed at the corresponding positions of the grouting section 13, with 1 set arranged on the upper and lower parts of the pipe section.

[0032] Each pipe section 1 is equipped with grouting function, continuously injecting drag-reducing mud 2 between the outer wall of pipe section 1 and the stratum 3 during the pipe jacking process. Pipe sections 1 with grouting holes 12 are arranged at intervals along the length of the pipe jacking process to replenish the mud sleeve. To achieve the best effect, the pre-embedded grouting pipe assembly 5 for grouting spans the grouting section 13, that is, the pre-embedded grouting pipe assembly 5 for grouting and the grouting section 13 are arranged in a cross shape, and the arrangement direction of the pre-embedded grouting pipe assembly 5 for grouting is perpendicular to the grouting section 13.

[0033] To assist in the formation of the grout sleeve, a grout delivery system 4 is provided on the inner wall of the pipe section 1. The grout delivery system 4 is used to transport the drag-reducing grout 2 from the ground grouting equipment to each grouting hole 11 and the replenishment grouting hole 12. The grout delivery system 4 includes branch grouting pipes 42 arranged circumferentially along the pipe section 1 and communicating with each grouting hole 11, and a main grouting pipe 41 arranged axially along the pipe section 1, which is connected to each branch grouting pipe 42. The main grouting pipe 41 extends axially along the pipe section 1, transporting the drag-reducing grout 2 from one end of the pipe section 1 to the other end; the branch grouting pipes 42 extend circumferentially along the pipe section 1, diverting the drag-reducing grout 2 in the main grouting pipe 41 to each grouting hole 11. A replenishment grouting pipe 43 is also provided axially inside the pipe section 1, which is connected to the main outlet 51 of the pre-embedded grouting pipe assembly 5 used for replenishment, and is used to deliver the drag-reducing grout 2 to the replenishment grouting hole 12. The grouting pipe 43 can be connected in parallel with the main grouting pipe 41, or it can be supplied with grout independently of the main grouting pipe 41.

[0034] In this embodiment, the main grouting pipe 41 and / or the branch grouting pipe 42 are fixed to the inner wall of the pipe section 1 by any of the following methods: snap-fit, pipe clamp, or snap-fit. After being fixed, the branch grouting pipes 42 are arranged in a U-shape. The grouting pipes 43 are continuously spliced ​​along the length of the pipe section 1, and multiple grouting pipes 43 are provided; each grouting pipe 43 is fixed to the bottom and top of the pipe section by snap-fit ​​or pipe clamp; the number of grouting pipes 43 is the same as the number of pre-embedded grouting pipe assemblies 5 used for grouting in the grouting section.

[0035] Each pipe section 1 has a set of grouting sections 13 in the middle of the pipe section, with the number of diversion ports 52 of the pre-embedded grouting pipe assembly 5 as the basis. m Group, the center distance between adjacent diversion ports 52 is d The grout diffuses into the formation in a semi-cylindrical planar pattern from each branch port 52 (the sidewalls of the pipe section are impermeable boundaries, and the grout only diffuses into the formation on one side). The grout diffusion radius of each branch port 52 is... R ( m ): ; in, Q The total grouting flow rate for a single pre-embedded grouting pipe assembly 5 ( L / min ); t Grouting duration ( min ); b The thickness is affected by the amount of mud injected in a single operation. m ); n Formation porosity; Grouting effect is affected by the grout diffusion radius. R Directly affects the slurry diffusion radius. R That is, the slurry diffusion depth perpendicular to the sidewall of the pipe section, when the diffusion radius satisfies R≥d / 2 At that time, the slurry diffusion areas of adjacent diversion ports 52 overlap, forming a continuous slurry band along the arrangement direction of the diversion ports 52, providing a judgment condition for the circumferential closure of the annular mud sleeve; with the target diffusion radius R Based on the design, the grouting pressure corresponding to the mainstream port 51 is... p 0 ( kPa Calculate using the following formula: ; in, p R For the slurry to diffuse to a radius R The remaining pressure at the location ( kPa ); μ To reduce the dynamic viscosity of mud 2 ( Pa s ); K Horizontal permeability coefficient of the formation ( m / s ); r 0 The radius of a single diversion port 52 ( m ); Setting the grouting section in the middle of the pipe section optimizes the slurry diffusion range and efficiency. The calculations in this application approximate the drag-reducing slurry as a Newtonian fluid, suitable for low-solids drag-reducing slurries; high-solids Bingham slurries require consideration of yield shear stress correction.

[0036] Considering that multiple sets of pre-embedded grouting pipe assemblies are uniformly arranged circumferentially on the same grouting section, the grout diffusion areas of each set will overlap when grouting simultaneously, resulting in a superposition effect in the local seepage field. This causes the actual seepage resistance to differ from the grouting condition of a single set of components. To match the circumferential arrangement of the pre-embedded grouting pipe assemblies and improve the accuracy of grouting pressure calculation, an inter-set seepage superposition correction coefficient can be introduced. β The calculation formula was revised. β This is the empirical correction coefficient for the superposition of seepage between multiple grouting port groups proposed in this invention, used to characterize the superposition and pressurization effect of the grout seepage field between the branch ports.

[0037] The revised formula for calculating grouting pressure is as follows: ; Among them, the intergroup seepage superposition correction coefficient β Calculate using the following formula: ; in, N The number of 5 sets of pre-embedded grouting pipe assemblies for synchronous grouting on the same grouting section 13; s The circumferential center-to-center distance between two adjacent sets of pre-embedded grouting pipe assemblies 5 on the outer wall of pipe section 1; exp It is a natural exponential function; When the circumferential spacing of adjacent pre-embedded grouting pipe assemblies 5 s≥2R At that time, the grout diffusion areas of each group of pre-embedded grouting pipe assemblies 5 did not overlap significantly, and the superposition effect was negligible. β When the value approaches 1, the formula degenerates into a planar seepage calculation form for a single component. This correction is based solely on the number and spacing of the pre-embedded grouting pipe components, and the calculation results can be flexibly adjusted according to different hole densities in the project to ensure uniform circumferential forming of the annular grout sleeve. This superimposed correction coefficient β The empirical formula only applies to the center distance between adjacent branch outlets. s≥R ;when s <R At this time, the grout diffusion areas of adjacent pre-embedded grouting pipe assemblies 5 completely overlap in the circumferential direction, the circumferential grout pressure distribution is uniform, and the seepage mainly develops unidirectionally in the radial direction perpendicular to the pipe wall. At this time, the unidirectional planar seepage model is used to calculate the grouting pressure, and the calculation formula is: ; in, The total grouting flow rate (L / min) within the same grouting section. L The total circumferential length (m) of the grouting pipe assembly 5 pre-embedded on the same grouting section.

[0038] β The engineering experience correction proposed in this invention can be further calibrated by combining on-site grouting tests.

[0039] During the pre-construction preparation stage, a reasonable grouting pressure range is initially determined through calculations based on the dimensions of the rectangular jacking pipe, the jacking length, and the soil geological conditions. During initial grouting, before the rectangular jacking pipe begins to advance, a mud pump is started to inject mud into the grouting pipe at a relatively low initial pressure. This allows the mud to slowly fill the gap between the jacking pipe tip and the soil. The initial pressure is usually slightly higher than the static earth pressure of the soil to ensure smooth mud injection without causing mud leakage or excessive soil disturbance due to excessive pressure. In some conventional soft soil strata, the initial pressure may be set at around 0.1–0.2 MPa. Furthermore, the grouting pressure is generally 0.02–0.04 MPa greater than the groundwater pressure (or 2–3 times the jacking water and soil pressure).

[0040] Based on the above-mentioned pipe jacking structure, the construction method of this application specifically includes the following steps: S1. When casting pipe section 1, pre-embed grouting pipe assembly 5 at the set position of pipe section 1. After the cast pipe section 1 is spliced ​​in sequence, connect each pre-embedded grouting pipe assembly 5 to the grouting system 4 to complete the connection of the entire pipeline and the sealing test. S2. Determine the process parameters for the grouting process, including the grouting working pressure, grouting flow rate, replenishment working pressure, replenishment flow rate, and grouting diffusion radius. R Grouting volume per pipe section and number of pipe section intervals for grouting; S3. Before starting the jacking construction, the principle of grouting before jacking is followed. A low-pressure, high-flow grouting pump is used to inject grout into the gap between the outer wall of pipe section 1 and the stratum 3 through grouting hole 11 until a complete closed annular mud sleeve is formed on the outer periphery of the first pipe section 1. S4. After the mud sleeve is formed and stabilized, start the jacking. Maintain continuous grouting throughout the jacking process. Dynamically adjust the grouting pressure and flow rate according to the real-time jacking speed to maintain the uniformity and continuity of the mud sleeve. S5. During the grouting operation, grouting is added to the grouting hole 12 to improve the uniformity and continuity of the mud sleeve; there are two working modes for the grouting operation. Conventional grouting mode: When the jacking reaches the pipe section 1 containing the grouting hole 12, the grouting pump is activated to perform fixed-point grouting through the grouting pipe 43 to fill the gaps caused by mud seepage and formation shrinkage. After the grouting reaches the standard, the grouting pipe 43 is shut off. Dynamic grouting mode: Real-time monitoring of jacking resistance and cross-sectional mud pressure. When the resistance suddenly increases or the local mud pressure is lower than the threshold, targeted grouting is performed at the abnormal pipe section until the monitoring indicators return to the normal range. The stable average jacking resistance measured during the trial jacking stage is used as the benchmark value. F 0, when the real-time jacking resistance is 0. F ≥(1.2~1.3) F At 0, it is determined that the resistance has increased sharply; The static pressure of groundwater at the corresponding cross section p w Based on the baseline, the lower limit threshold is taken as... p w +0.01~0.02MPa, when the local mud pressure is lower than this threshold, it is determined to be insufficient mud pressure; When a sudden increase in resistance or a local mud pressure falls below the threshold occurs, targeted mud replenishment is performed at the abnormal pipe section location until the monitoring indicators return to the normal range.

[0041] S6. After the entire section of jacking construction is completed, the grouting and replenishment are closed in sequence, and the main outlet of all pre-embedded grouting pipe components 5 is sealed with the plugging device 53 to maintain the long-term sealing and stability of the mud sleeve.

[0042] During grouting, the principle of grouting before jacking and grouting simultaneously with jacking should be followed, and a low-pressure, high-flow-rate grouting pump should be used. For grout replenishment, the principle of combining synchronous grouting with grout replenishment and timely grout replenishment should be followed, and a high-pressure, low-flow-rate grouting pump can be used.

[0043] During the continuous grouting stage, the grouting pressure and grouting flow rate are dynamically matched according to the following rules: During the initial grouting and ring-forming stage, the grouting pressure is higher than the static earth pressure, ranging from 0.1 to 0.3 MPa, with the grouting flow rate at the lower limit. The specific value is determined based on the soil properties. For example, in silty clay, the grouting pressure can be controlled at around 0.1 MPa, while in silty clay, the grouting pressure can be appropriately increased to 0.2–0.3 MPa. During the jacking process, the grouting pressure should be dynamically adjusted according to the jacking speed and changes in the soil. If the jacking speed increases, the grouting pressure can be appropriately increased to ensure that the grout can promptly fill the newly formed gaps between the jacking pipe and the soil; if the soil hardens, the grouting pressure also needs to be appropriately increased to ensure smooth grout injection.

[0044] During the synchronous jacking and grouting stage, the grouting pressure and flow rate are dynamically adjusted according to the jacking speed and soil properties: when the jacking speed increases or the soil hardness increases, the grouting pressure and flow rate are increased accordingly to fill the annular gap generated by jacking in a timely manner.

[0045] When the jacking speed slows down or the soil becomes soft, the grouting pressure and flow rate should be reduced accordingly to avoid mud leakage. The grouting flow rate should be determined based on the grouting pressure and the size of the jacking pipe. The overall flow rate for continuous grouting should be controlled within the range of 10–50 L / min. In the initial grouting stage, the grouting flow rate can be appropriately reduced to prevent mud leakage. As jacking progresses, the grouting flow rate should be adjusted according to the changes in the gap between the jacking pipe and the soil and the jacking speed to ensure that the mud can be injected continuously and uniformly, allowing the mud jacket to gradually form and remain intact.

[0046] In actual construction, sealing is required between pipe sections. In this embodiment, a sealing system is introduced. The sealing system consists of a front-end sealing device, a rear-end sealing device, and an inter-section sealing device. The front-end sealing device is fixedly installed at the front end of the jacking pipe, using elastic rubber seals or packing seals, and is matched to the size of the front end of the jacking pipe to prevent drag-reducing slurry from leaking to the front end of the jacking pipe. The rear-end sealing device is fixedly installed at the rear end of the jacking pipe structure, using a combination of mechanical seals and rubber seals to prevent drag-reducing slurry from flowing back to the rear end of the jacking pipe. The inter-section sealing device is installed at the socket joint of adjacent pipe sections and is an elastic corrosion-resistant rubber sealing ring. When adjacent jacking pipe sections are socketed, the rubber sealing ring is uniformly compressed, sealing the joint gap.

[0047] The entire jacking operation is subject to closed-loop attitude control to maintain the integrity of the annular mud jacket. Attitude control includes two aspects: guidance and navigation, and monitoring and correction. The guidance and navigation process involves: deploying a laser guidance system at the front end of the pipe jacking structure to acquire real-time data on the jacking direction and spatial attitude of the pipe; dynamically adjusting the jacking force distribution of the jacks based on the feedback data; correcting the pipe jacking deviation; and ensuring that the pipe jacks advance along the designed axis.

[0048] The monitoring and correction process involves installing tilt sensors and displacement sensors on the jacking pipe sections to monitor the jacking attitude parameters in real time.

[0049] When the tilt angle or axis displacement deviation is detected to exceed the preset allowable threshold, the jacking operation is suspended and the cause of the abnormal posture is determined.

[0050] To address the attitude deviation caused by uneven soil conditions, the attitude of the jacking pipe is corrected by increasing the grouting volume on the deviated side or adjusting the jacking force, thus maintaining the continuity and integrity of the annular mud sleeve.

[0051] To verify the mud sleeve forming and drag reduction effects, an indoor comparative test using similar scaled-down models was conducted (the model components were scaled down according to geometric similarity ratios; therefore, the dimensions of components such as the diversion port in the model are the scaled-down test dimensions, not equivalent to the actual engineering prototype pipe section dimensions). The test conditions and results are as follows: The similar scale model test used rectangular pipe sections with a cross-sectional dimension of 40cm width and 25cm height, and a single section length of 20cm, for a total of 6 sections spliced ​​together. The test stratum was remolded silty clay with a porosity of [missing information]. n =0.42, formation horizontal permeability coefficient K =5×10 -7 m / s; drag-reducing mud dynamic viscosity μ =0.12Pa s. A single set of pre-embedded grouting pipe assembly 5 is equipped with 7 diversion ports 52, each diversion port 52 having a diameter of 3mm and a center-to-center distance of 5cm between adjacent diversion ports (meeting the requirements). R≥d / 2 (Criteria for determining grout overlap); setting the target grout diffusion radius. R =3cm, and the design value of the grouting pressure at the main inlet, calculated based on the independent seepage formula for a single component, is 0.12. MPa Grouting flow rate of a single component 2 L / min The entire process follows the construction procedure of first injecting and then grouting, and then filling the grout in stages.

[0052] Test results: The circumferential closure rate of the annular mud sleeve reached over 95% throughout the jacking process, with no significant axial breaks. The average jacking resistance was measured to be 4.6. kN Under the same geological conditions, pipe section dimensions, and jacking conditions, using the traditional single-point grouting method with the jacking head positioned behind the pipe section, without pre-embedded grouting in the pipe sections or a staged grouting system, the grouting pressure is consistently 0.12. MPaTest results: The mud sleeve only formed locally in the head section, and multiple sections of subsequent pipe sections experienced breakage; the circumferential closure rate was approximately 58%; the average jacking resistance was measured to be 7.7. kN Compared with traditional grouting methods, the jacking resistance of the present invention is reduced by about 40%, the integrity and continuity of the annular mud sleeve are significantly improved, and the drag reduction effect is stable.

[0053] Furthermore, to verify the superposition effect of seepage fields during simultaneous grouting of multiple components, an inter-component seepage superposition correction coefficient was introduced. β The grouting pressure was checked. In this model test, two sets of pre-embedded grouting pipe assemblies were symmetrically arranged at the same grouting section, located at the top and bottom of the pipe section respectively, with the circumferential center-to-center distance between adjacent assemblies being [missing information]. s=0.3m Substituting into the superposition correction coefficient formula, we get... β The pressure increase caused by the inter-group superposition is less than 0.2%, and the corrected grouting pressure at the main outlet is basically consistent with the initial design value.

[0054] The basic principles of this application have been described above with reference to specific embodiments. However, it should be noted that the advantages, benefits, and effects mentioned in this application are merely examples and not limitations, and should not be considered as essential features of each embodiment of this application. Furthermore, the specific details disclosed above are for illustrative and facilitative purposes only, and are not limitations. These details do not limit the application to the necessity of employing the aforementioned specific details for implementation.

[0055] The block diagrams of devices, apparatuses, devices, and systems involved in this application are merely illustrative examples and are not intended to require or imply that they must be connected, arranged, or configured in the manner shown in the block diagrams. As those skilled in the art will recognize, these devices, apparatuses, devices, and systems can be connected, arranged, and configured in any manner. Words such as “comprising,” “including,” “having,” etc., are open-ended terms meaning “including but not limited to,” and are used interchangeably with them. The terms “or” and “and” as used herein refer to the terms “and / or,” and are used interchangeably with them unless the context clearly indicates otherwise. The term “such as” as used herein refers to the phrase “such as but not limited to,” and is used interchangeably with it.

Claims

1. A jacking pipe structure for assisting in the forming of a mud sleeve, characterized in that, The jacking pipe is formed by splicing at least two sets of pipe sections (1) with bearings; the gap between the pipe section (1) and the formation (3) is filled with drag-reducing mud (2) to form a mud sleeve; At least one cross section of each pipe section (1) is used as a grouting section (13). Grouting holes (11) are arranged in the plane of the grouting section (13). The grouting holes (11) are distributed along the circumference of the pipe section in the grouting section (13). On the pipe wall of at least one set of pipe sections (1), multiple sets of grouting holes (12) are arranged along the axial direction of the pipe section (1). The pipe sections with grouting holes (12) are arranged at intervals along the length of the jacking pipe. The openings of the grouting holes (11) and grouting holes (12) on the inner wall of the pipe section (1) are used as inlets, and the openings of the grouting holes (11) and grouting holes (12) on the outer wall of the pipe section (1) are used as outlets.

2. The jacking structure for assisting mud sleeve forming according to claim 1, characterized in that, Each pipe section (1) is pre-embedded with a pre-embedded grouting pipe assembly (5) for grouting and / or grouting. The pre-embedded grouting pipe assembly (5) includes a main flow port (51) as the inlet and various branch ports (52) connected to the main flow port (51). The inlet of the main flow port (51) is flush with the inner wall of the pipe section (1) as the inlet of the grouting hole (11) or the grouting hole (12). The outlet of the branch port (52) is flush with the outer wall of the pipe section (1) as the outlet of the grouting hole (11) or the grouting hole (12). The branch ports (52) are arranged at equal intervals along a straight line.

3. The jacking structure for assisting mud sleeve forming according to claim 2, characterized in that, The inner wall of the main outlet (51) of the pre-embedded grouting pipe assembly (5) is threaded to connect a detachable plug (53) to seal the main outlet (51); the pre-embedded grouting pipe assembly (5) has 7 to 10 sets of branch outlets (52), and each branch outlet (52) has a screen hole at its outlet; the diameter of the branch outlet (52) is 15 to 30 mm, and the distance between adjacent branch outlets (52) is 30 to 80 cm.

4. The jacking structure for assisting mud sleeve forming according to claim 2, characterized in that, Each of the pipe sections (1) is provided with a pre-embedded grouting pipe assembly (5) configured for grouting. Pipe sections (1) with grouting holes (12) are arranged at intervals between each pipe section (1) along the length of the jacking pipe. The pre-embedded grouting pipe assembly (5) for grouting passes through the corresponding grouting section (13), and its extension direction is perpendicular to the grouting section (13).

5. The jacking structure for assisting mud sleeve forming according to claim 2, characterized in that, It also includes a grouting system (4) installed on the inner wall of the pipe section (1). The grouting system (4) includes branch grouting pipes (42) arranged circumferentially along the pipe section (1) and connected to each grouting hole (11). The main grouting pipe (41) arranged axially along the pipe section (1) is connected to each branch grouting pipe (42). A grouting replenishment pipe (43) is also installed axially inside the pipe section (1). The grouting replenishment pipe (43) is connected to the main outlet (51) of the pre-embedded grouting pipe assembly (5) used for grouting.

6. The jacking structure for assisting mud sleeve forming according to claim 5, characterized in that, The main grouting pipe (41) and / or the branch grouting pipe (42) are fixed to the inner wall of the pipe section (1) by any of the following methods: snap fastener, pipe clamp, or snap-fit; the main grouting pipe (41) is connected to the branch grouting pipe (42) through the N-way fitting, and the grouting pipe (43) and / or the branch grouting pipe (42) are connected to the main outlet (51) of the corresponding pre-embedded grouting pipe assembly (5) through bolt joints.

7. The jacking structure for assisting mud sleeve forming according to claim 2, characterized in that, Each pipe section (1) has a set of grouting sections (13) in the middle of the pipe section, with the number of branch ports (52) of the pre-embedded grouting pipe assembly (5) being as follows: m Group, the center distance between adjacent diversion ports (52) is d The grouting diffusion radius of each branch port (52) is R : ； in, Q The total grouting flow rate for a single pre-embedded grouting pipe assembly (5); t This refers to the duration of grouting. b The thickness is affected by the amount of mud injected in a single injection; n This represents the formation porosity.

8. The jacking structure for assisting mud sleeve forming according to claim 7, characterized in that, With target diffusion radius R Based on the design, the grouting pressure corresponding to the main outlet (51) is... p 0 is calculated using the following formula: ； in, p R For the slurry to diffuse to a radius R The remaining pressure at the location; μ To reduce the dynamic viscosity of the drag-reducing mud (2); K The horizontal permeability coefficient of the formation; r 0 represents the radius of a single branch port (52); β This is the correction factor for the superposition of intergroup seepage.

9. A method for forming a mud sleeve during construction, characterized in that, The construction using a pipe jacking structure for assisting mud sleeve forming as described in any one of claims 1 to 8 specifically includes the following steps: S1. When casting the pipe section (1), pre-embed the pre-embedded grouting pipe assembly (5) at the set position of the pipe section (1). After splicing the cast pipe section (1) in sequence, connect each pre-embedded grouting pipe assembly (5) with the grouting system (4) to complete the connection of the entire pipeline and the sealing test. S2. Determine the process parameters for the grouting process, including the grouting working pressure, grouting flow rate, replenishment working pressure, replenishment flow rate, and grouting diffusion radius. R Grouting volume per pipe section and number of pipe section intervals for grouting; S3. Before the jacking construction starts, the principle of grouting before jacking is followed. Grout is injected into the gap between the outer wall of the pipe section (1) and the stratum (3) through the grouting hole (11) until a complete closed annular mud sleeve is formed on the outer periphery of the first pipe section (1). S4. After the mud sleeve is formed and stabilized, start the jacking. Maintain continuous grouting throughout the jacking process. Dynamically adjust the grouting pressure and flow rate according to the real-time jacking speed to maintain the uniformity and continuity of the mud sleeve. S5. During the grouting operation, the grouting hole (12) is grouted to improve the uniformity and continuity of the mud sleeve. S6. After the jacking construction of the whole section is completed, the grouting and replenishment are closed in sequence, and the main outlet of all the pre-embedded grouting pipe components (5) is sealed with a plug (53) to keep the mud sleeve sealed and stable for a long time.

10. A mud sleeve forming construction method according to claim 9, characterized in that, In S5, the grouting operation has the following two working modes; Conventional grouting mode: When the jacking reaches the pipe section (1) containing the grouting hole (12), the grouting pump is activated to grout the pipe (43) at a fixed point to fill the gaps caused by mud seepage and formation shrinkage. After the grouting reaches the standard, the grouting pipe (43) is shut off. Dynamic grouting mode: Real-time monitoring of jacking resistance and cross-sectional mud pressure. When resistance suddenly increases or local mud pressure falls below the threshold, targeted grouting is performed at the abnormal pipe section until the monitoring indicators return to the normal range.

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