Bag type grouting reinforced railroad bed structure and construction method

Abstract

The invention relates to the technical field of roadbed reinforcement construction, and discloses a bag type grouting reinforcement railway roadbed structure and a construction method. The structure comprises a roadbed and a bag type grouting reinforcement assembly. A plurality of rows of grouting lifting holes are formed in the roadbed; the bag type grouting reinforcement assembly comprises a grouting bag pipe assembly, the grouting bag pipe assembly comprises a grouting pipe and a grouting bag arranged on the grouting pipe, a grout outlet is formed in the grouting pipe, and a grout outlet valve is arranged at the grout outlet. Slurry with the specified volume is injected into the grouting bag by controlling the slurry outlet, accurate compensation lifting of subgrade settlement is achieved, and the soil body is compacted to a certain degree by combining extrusion of the grouting bag on the surrounding soil body in the volume expansion process of the grouting bag; in addition, the interface frictional resistance generated by the grouting bag after grouting expansion and the soil body around the grouting bag can provide continuously increasing drawing force, and the risk of sudden instability of the roadbed is effectively reduced. In addition, a composite roadbed structure is formed by a solidified body formed after the cement grout is solidified and roadbed filler, and the rigidity of the roadbed can be improved.

Description

Technical Field

[0001] This invention relates to the field of roadbed reinforcement construction technology, and in particular to a bladder-type grouting reinforcement method for railway roadbed structures. Background Technology

[0002] Under seismic loading, railway subgrades primarily exhibit typical seismic damage forms such as embankment cracking, slope collapse, and subgrade settlement. These damages not only lead to residual deformation and stiffness degradation of the subgrade, but the settlement deformation of the subgrade surface is also transmitted to the track structure through interlayer transfer effects, causing track geometric and stiffness irregularities. This further exacerbates the dynamic interaction between the train-track-subgrade system, seriously threatening traffic safety. Therefore, developing practical and feasible railway subgrade reinforcement and seismic damage repair technologies has become a critical issue urgently needing to be addressed in the current railway engineering field.

[0003] Currently, commonly used methods for reinforcing railway subgrades mainly include: (1) Replacement method and geosynthetic reinforcement method. Replacement method and geosynthetic reinforcement method are usually more suitable for the subgrade reinforcement of newly built lines. In the repair of seismic damage of operating lines, there are implementation difficulties such as large construction interference and long construction period.

[0004] (2) Pile reinforcement method. This method mainly includes reinforcement using lime-soil compaction piles, cement-soil piles, etc. It has the disadvantages of poor controllability of construction quality, difficulty in accurately controlling the reinforcement range, and environmental problems such as mud pollution, noise and vibration.

[0005] (3) Prestressed subgrade reinforcement method. This method mainly uses prestressed steel bars to apply prestress to both sides of the subgrade slope to achieve railway subgrade reinforcement. However, its design calculation theory and construction technology are not yet mature and cannot be applied to railway subgrade reinforcement.

[0006] (4) Grouting method: This method involves injecting a specific grout into the subgrade soil to fill pores and compact the soil, thereby improving the overall density and bearing capacity of the subgrade. It is considered a relatively mature and effective means of railway subgrade reinforcement. However, traditional grouting technology still has significant shortcomings: the flow path and diffusion range of the grout in the soil are difficult to control precisely, making it difficult to guarantee the reinforcement range, the uniformity of grout distribution, and the injection volume. This not only affects the reliability of the reinforcement effect but may also lead to increased costs and environmental pollution due to grout waste or diffusion to non-target areas. In addition, traditional grouting technology has weak control over the amount of subgrade uplift during construction, which can easily result in over- or under-uplift. It can also easily disturb areas of the subgrade that are not damaged, making it difficult to achieve accurate restoration of subgrade settlement and local reinforcement of earthquake-damaged areas. Especially for ballastless tracks with high structural rigidity and sensitivity to deformation, the margin for adjusting the track surface elevation is limited, and the requirements for controlling the settlement of the roadbed are extremely strict. Therefore, when using conventional grouting technology for post-earthquake repair, it is often difficult to accurately restore the smoothness of the track surface and effectively reinforce the local damaged areas.

[0007] Therefore, there is an urgent need to develop a new railway subgrade reinforcement structure to solve the problems existing in the current technology. Summary of the Invention

[0008] The main objective of this invention is to provide a bladder-type grouting reinforcement structure for railway subgrade, which enables precise control, efficient reinforcement, and is environmentally friendly, thereby improving the seismic toughness and long-term service performance of the railway subgrade. The specific solution is as follows: A bladder-type grouting reinforcement structure for railway subgrade includes a subgrade and a bladder-type grouting reinforcement component; The roadbed is set on the foundation, and the roadbed includes a roadbed slope; the roadbed has multiple rows of grouting lifting holes that penetrate the roadbed slope and are provided along the roadbed line direction and / or the roadbed height direction; The bladder-type grouting reinforcement assembly includes a grouting bladder tube assembly corresponding to the grouting lifting hole. The grouting bladder tube assembly includes a grouting pipe and a grouting bladder bag. One or at least two grouting bladder bags are arranged along the length of the grouting pipe. The grouting pipe is provided with a grout outlet, which is connected to the grouting bladder bag. A grout outlet valve is provided at the grout outlet.

[0009] Preferably, the damage range of the roadbed includes: the length of damage along the route direction. Lateral width from the roadbed slope towards the centerline of the line Depth of damage to the roadbed and roadbed settlement .

[0010] Preferably, the equivalent radius of the reinforcement range of a single grouting bag Calculate using the following formula: ; in: The radius of the grouting bag, This refers to the vertical stress at the grouting lifting hole. The cohesion of the roadbed fill material, The internal friction angle of the roadbed fill material. The elastic modulus of the roadbed fill material. The Poisson's ratio of the roadbed fill material; Vertical stress at the grouting lifting hole Calculate using the following formula: ; in: For the first The unit weight of the subgrade fill material, For the first The thickness of the subgrade fill material, This refers to the total number of layers of subgrade fill material above the grouting lifting hole; Equivalent radius of reinforcement range of a single grouting bag Spacing between adjacent grouting lifting holes along the track direction The two should satisfy the following relationship: ; in: The overlap factor for the reinforcement range along the route is 0.8-1.0; Number of rows of grouting lifting holes along the track direction Calculate using the following formula: ; in: It is a rounding function; The spacing between adjacent grouting lifting holes along the roadbed depth direction is The two should satisfy the following relationship: ; in: The overlap factor for the reinforcement range along the roadbed depth direction is 0.5-1.0; Number of rows of grouting lifting holes along the depth direction of the roadbed Calculate using the following formula: ; Total number of grouting lift holes within the subgrade damage area Satisfy the following expression: .

[0011] Preferably, the length of the grouting lifting hole Calculate using the following formula: ; in: This refers to the vertical distance from the grouting lifting hole to the roadbed surface. The slope ratio of the roadbed side slope. The angle between the grouting lifting hole and the horizontal direction.

[0012] Preferably, the angle between the row of grouting lifting holes closest to the roadbed surface and the horizontal direction is... The vertical distance from the grouting lifting holes closest to the roadbed surface is 5°-10°. Not less than 2m.

[0013] Grouting pressure of a single grouting lift hole Calculate using the following formula: .

[0014] Preferably, the total grouting volume required to raise the roadbed settlement to the design elevation of the roadbed surface. Calculate using the following formula: ; in: This is the grouting volume correction factor, with a value range of 0.8-1.2; The volume of grout injected into each grouting tube The calculation expression is as follows ; Number of grouting bladders on a single grouting bladder assembly Based on the volume of a single grouting bag and the volume of grout injected by a single grouting tube Sure: +1.

[0015] Preferably, the length of the grouting bladder assembly With the length of the grouting lifting hole Equal; the diameter of the grouting tube in the grouting bladder assembly. Diameter of the grouting lifting hole satisfy: ; Diameter of grouting bladder With roadbed settlement The following conditions must be met: , This is the first proportionality coefficient, with a value ranging from 1 to 10; Length of grouting bladder With roadbed settlement The following conditions must be met: , This is the second proportionality coefficient, with a value range of 5-20.

[0016] Preferably, the number of grout outlet holes on a single grouting bladder assembly is... and the number of grouting bags equal; Diameter of slurry outlet Calculate using the following formula: ; in: The adjustment factor is set between 0.8 and 1.0. The density of the slurry; This represents the grouting flow rate per single outlet hole.

[0017] Preferably, the grouting pipe is also provided with overflow holes, and the number of overflow holes on a single grouting bladder assembly is [number missing]. There are 2-6 overflow holes; the diameter of the overflow holes is... With the diameter of the slurry outlet same.

[0018] This invention also discloses a construction method for reinforcing railway subgrade structures using bladder-type grouting as described above, comprising the following steps: Step 1: Conduct a comprehensive survey of the roadbed to identify the settlement sections, settlement amounts, and damage ranges. Use a total station or laser measuring equipment to compare the post-earthquake roadbed elevation with the original design elevation to obtain the actual required roadbed uplift and reinforcement range. Step 2: Based on the settlement zone and the extent of damage, determine the layout scheme of the grouting lift holes. The layout scheme of the grouting lift holes includes: For grouting lifting holes, this includes the number of rows, depth, angle with the horizontal line, and location; For grouting bags, this includes the quantity, size, shape, spacing, and installation position on the grouting section of the grouting pipe; Step 3: Move the drilling rig to the drilling position and drill to obtain the grouting lifting hole; Step 4: Lower the grouting bladder assembly to the predetermined position and adjust the grout outlet direction mark so that the grouting bladder can lift the roadbed settlement or reinforce the damaged area of ​​the roadbed after it expands. Step 5: Grout the grouting bladder assembly, starting with the area of ​​greatest settlement; this results in a bladder-type grouting reinforcement of the railway subgrade structure.

[0019] The effect of applying the technical solution of this invention is: 1. The bladder-type grouting reinforcement railway subgrade structure of the present invention includes a subgrade and a bladder-type grouting reinforcement component; the subgrade is set on the foundation, and the subgrade includes a subgrade slope; multiple rows of grouting lifting holes are provided on the subgrade, penetrating the subgrade slope and along the subgrade line direction and / or the subgrade height direction; the bladder-type grouting reinforcement component includes a grouting bladder tube assembly corresponding to the grouting lifting holes, the grouting bladder tube assembly includes a grouting pipe and a grouting bladder bag, one or at least two grouting bladder bags are arranged along the length direction of the grouting pipe, the grouting pipe is provided with a grout outlet, the grout outlet is connected to the grouting bladder bag, and a grout outlet valve is provided at the grout outlet. This invention achieves precise compensation and lifting of roadbed settlement by controlling the injection of a specified volume of grout into a grouting bag through the grout outlet. Combined with the compression of the surrounding soil during the expansion of the grouting bag, the soil is compacted to a certain extent. Furthermore, the interfacial friction between the expanded grouting bag and the surrounding soil provides continuously increasing pull-out force, effectively reducing the risk of sudden roadbed instability. In addition, the solidified cement grout forms a composite roadbed structure with the roadbed filler, increasing the roadbed stiffness. Compared with traditional roadbed reinforcement methods, this roadbed reinforcement structure allows for refined control of roadbed settlement recovery and improves the roadbed's bearing capacity, providing a new approach to roadbed reinforcement.

[0020] 2. The bladder-type grouting reinforcement of railway subgrade structure disclosed in this invention effectively constrains the diffusion of grout in the subgrade through the grouting bladder portion of the grouting bladder assembly, allowing the grout to be released directionally within the reinforcement range. This avoids the common problems of grout leakage, grout runoff, and disordered grout diffusion in traditional grouting processes, significantly improving grout utilization. While ensuring the reinforcement effect, it reduces the amount of grout used, thereby reducing project costs and effectively minimizing adverse impacts on groundwater and the surrounding environment. It has significant economic and environmental benefits.

[0021] 3. In this invention, the grouting bladder assembly can be flexibly configured according to the roadbed settlement, and targeted grouting is achieved through the expansion of the grouting bladder, thereby precisely controlling the lifting of the settled roadbed. By precisely adjusting the grouting volume and grouting range, the elevation restoration can be gradually advanced, avoiding excessive lifting or uneven local lifting, thus ensuring the controllability and accuracy of the roadbed lifting process and significantly improving the reliability of construction.

[0022] 4. The arrangement of the grouting bags in this invention can be tailored to the specific damaged areas of the roadbed, thereby achieving targeted reinforcement. By grouting and reinforcing the damaged areas, the overall bearing capacity of the roadbed can be effectively enhanced, while avoiding disturbance to undamaged areas, reducing material consumption and construction interference, and improving the efficiency and rationality of the overall structural reinforcement. Attached Figure Description

[0023] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced 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 the structures shown in these drawings without creative effort.

[0024] Figure 1 This is a schematic diagram of the cross-sectional arrangement of the grouting lifting holes of the present invention; Figure 2 This is a schematic diagram of the planar arrangement of the grouting lifting holes of the present invention; Figure 3 This is a schematic diagram of the geometric parameters of the grouting bladder assembly of the present invention; Figure 4 This is a schematic cross-sectional view of a bladder-type grouting reinforcement method for railway subgrade structure according to the present invention; Figure 5 This is a plan view of a bladder-type grouting reinforcement method for railway subgrade structure according to the present invention; Figure 6 This is a schematic diagram of the grouting bladder assembly in this invention; Figure 7 for Figure 6 Enlarged view of the structure at point A in the middle; Figure 8 for Figure 6 Enlarged view of the structure at point B in the middle.

[0025] Explanation of icon numbers: 1-Foundation, 2-Subgrade, 3-Subgrade slope, 4-Subgrade centerline, 5-Shoulder, 6-Slope toe line, 7-Grouting lifting hole, 8-Grouting machine, 9-Grouting bladder assembly, 10-Grouting pipe, 11-Grouting outlet, 12-Grouting valve, 13-Grouting bladder, 14-Overflow outlet, 15-Overflow valve, 16-Grouting outlet direction mark.

[0026] The realization of the objective, functional features and advantages of the present invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0027] 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 a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0028] Example: This embodiment proposes a method for reinforcing railway subgrade structures using bladder-type grouting. By arranging grouting lifting holes in subgrade settlement and damage zones after an earthquake, and installing grouting bladder components at corresponding hole locations, grout is injected into the bladders via grouting pipes, thereby lifting and reinforcing the subgrade. This method not only effectively overcomes the limitations of traditional grouting techniques in terms of reinforcement range and lifting volume control, but also further improves the overall structural strength and seismic performance of the subgrade.

[0029] The specific solution of this embodiment is as follows: See details Figures 1-8 As shown, the bladder-type grouting reinforcement of railway subgrade structure provided in this embodiment specifically includes subgrade 2 and bladder-type grouting reinforcement components, as detailed below: The roadbed 2 is set on the foundation 1, see details. Figure 4 The roadbed 2 includes roadbed slope 3, roadbed centerline 4, road shoulder 5, and slope toe line 6.

[0030] See details Figure 1 , Figure 2 , Figure 4 and Figure 5 The roadbed 2 has multiple rows of grouting lifting holes 7 that penetrate the roadbed slope 2.1 and are provided along the roadbed line direction and / or the roadbed height direction. Preferably, the multiple rows of grouting lifting holes are drilled downwards at a small angle from the roadbed slope towards the roadbed centerline, and are symmetrically arranged along the roadbed centerline 4, and are spaced apart along the roadbed height direction and line direction.

[0031] See details Figure 3 , Figure 4 and Figure 6 The bladder-type grouting reinforcement assembly includes a grouting bladder tube assembly 9 corresponding to the grouting lifting hole 7. The grouting bladder tube assembly 9 includes a grouting pipe 10 and grouting bladders 13. One or at least two grouting bladders 13 are arranged along the length of the grouting pipe 10. A grout outlet 11 is provided on the grouting pipe 10, and the grout outlet 11 communicates with the grouting bladders 13. A grout outlet valve 12 (preferably an electromagnetic control valve) is provided at the grout outlet 11. See details... Figure 7 The grouting pipe 10 is also provided with an overflow hole 14, and an overflow valve 15 (preferably an electromagnetic control valve) is provided at the overflow hole 14, as detailed below. Figure 8 The grout is injected into the grouting bags 13 through the grouting pipe 10 to achieve directional diffusion and lifting. The grouting volume of each grouting bag can be controlled by the grout outlet valve 12, and the grouting volume of the overflow outlet can be controlled by the overflow valve 15. The grouting pipe 10 is connected to an external grouting machine 8.

[0032] In this embodiment, the layout of the grouting lifting holes is further determined based on the settlement and damage range of the roadbed after the earthquake. The damage range of the roadbed includes the damage length of the roadbed along the route direction. Lateral width from the roadbed slope towards the centerline of the line Depth of damage to the roadbed and roadbed settlement Based on the extent of roadbed damage after the earthquake, grouting lifting holes were installed along the roadbed alignment and height. See details... Figure 1 , Figure 2 , Figure 4 and Figure 5 .

[0033] In this embodiment, the equivalent radius of the reinforcement range of a single grouting bag is... The following method is used for calculation: ; in: The radius of the grouting bag, This refers to the vertical stress at the grouting lifting hole. The cohesion of the roadbed fill material, The internal friction angle of the roadbed fill material. The elastic modulus of the roadbed fill material. This is the Poisson's ratio of the roadbed fill material.

[0034] Further preferably, in this embodiment, the vertical stress at the grouting lifting hole... It can be calculated using the following method: ; in: For the first The unit weight of the subgrade fill material, For the first The thickness of the subgrade fill material, This refers to the total number of layers of subgrade fill material above the grouting lifting hole.

[0035] The equivalent radius of a single grouting bag reinforcement range is The spacing between adjacent grouting lifting holes along the track direction is See details Figure 2 The two should satisfy the following relationship: ; in: The overlap coefficient for the reinforcement range along the route is 0.8-1.0.

[0036] In this embodiment, the spacing between adjacent grouting lifting holes along the track direction Number of rows of grouting lifting holes along the track direction Calculate using the following formula: ; in: It is a rounding function; Along the route direction, an additional row of grouting lift holes is added at each end of the subgrade damage area. The spacing between adjacent grouting lift holes along the subgrade depth direction is... The two should satisfy the following relationship: ; in: The overlap coefficient for the reinforcement range along the depth direction of the roadbed is 0.5-1.0.

[0037] Furthermore, based on the spacing between adjacent grouting lifting holes along the roadbed depth direction... Determine the number of rows of grouting lift holes along the depth direction of the roadbed. ,as follows: .

[0038] Based on the number of rows of grouting lift holes along the track direction and the number of rows of grouting lifting holes along the depth direction of the roadbed Determine the total number of grouting lift holes within the subgrade damage area. Satisfy the following expression: .

[0039] In this embodiment, the length of the grouting lifting hole Determine as follows: ; in: This refers to the vertical distance from the grouting lifting hole to the roadbed surface. The slope ratio of the roadbed side slope. The angle between the grouting lifting hole and the horizontal direction.

[0040] More preferably, the row of grouting lifting holes closest to the roadbed surface (i.e., the top row of grouting lifting holes) has a preferred inclination angle. The angle is 5°-10°, representing the vertical distance from the top row of grouting lifting holes (i.e., the row of grouting lifting holes closest to the roadbed surface) to the roadbed surface. It should be no less than 2m.

[0041] In this embodiment, grouting lifting holes are arranged along the roadbed height direction and the track direction within the roadbed slope area. The number of grouting lifting holes is [number] rows along the slope direction. There are 1, 2, 3, and 4 rows. The spacing of the holes along the line direction is... The spacing is 1.0m-8.0m along the roadbed slope direction. The depth is 1.0m-4.0m; the angle between the grouting lifting hole and the horizontal line. The angle is 10°-25°, and the drilling is directed downwards.

[0042] In this embodiment, the diameter of the grouting lifting hole It can be 70-110mm.

[0043] In this embodiment, it is further preferred that the grouting pressure of the grouting bladder is... The grouting pressure should be determined comprehensively based on the depth of the grouting lift hole and the mechanical parameters of the subgrade fill material to ensure that the grout bag can effectively expand and achieve subgrade lift, while avoiding excessive heave or secondary damage. The grouting pressure for a single grouting lift hole... It can be determined according to the following relationship: .

[0044] In this embodiment, a graded pressurization method is adopted during the grouting process. The grouting pressure is gradually increased in stages from 0.02 to 0.05 MPa, and the grouting pressure-grouting volume-time curve is monitored in real time. When the pressure increases significantly and the change in grouting volume slows down, it is determined that the grouting bladder has reached an effective expansion state.

[0045] Total grouting volume required to raise the roadbed to the design elevation of the roadbed surface The following method is used for calculation: ; in: This is the grouting volume correction factor, with a value range of 0.8-1.2.

[0046] In this embodiment, each grouting tube should be injected with grout volume of [volume missing]. The calculation expression is as follows .

[0047] In this embodiment, the length of the grouting bladder assembly The length can be determined based on the length of the grouting lifting hole. and satisfy .

[0048] In this embodiment, the diameter of the grouting tube in the grouting bladder assembly is... It should be smaller than the diameter of the grouting lifting hole. The following conditions must be met between the two: .

[0049] In this embodiment, the diameter of the grouting bladder is... Based on the amount of roadbed settlement after the earthquake To determine the diameter of the grouting bag With roadbed settlement The following conditions must be met: , This is the first proportionality coefficient, with a value range of 1-10.

[0050] When the roadbed settlement For larger settlements, larger diameter grouting bags should be used; when the roadbed settlement is large... For larger sizes, smaller diameter grouting bags should be used.

[0051] In this embodiment, the length of the grouting bladder is... Based on the amount of roadbed settlement after the earthquake Determine the length of the grouting bag. With roadbed settlement The following conditions must be met: , This is the second proportionality coefficient, with a value range of 5-20.

[0052] After full expansion, the grouting bladder becomes capsule-shaped, and the diameter of the grouting bladder is... The length of the grouting bag can range from 0.5 to 1.5 meters. The spacing between grouting bags on the same grouting bladder assembly can be 0.5-3.0m, and the length of the grouting bags should match the spacing between the grouting bags. In addition, the diameter of the grouting bags... ,length and spacing It can also be set according to actual needs; no specific restrictions are made here.

[0053] In this embodiment, the number of grouting bladders on a single grouting bladder assembly is... According to the volume of a single grouting bag The volume of grout to be injected into a single grouting tube should be [volume missing]. Sure: +1.

[0054] In this embodiment, the grouting bladder is further preferably made of high-strength geosynthetic material or high-density polyethylene geomembrane (see prior art), with a puncture resistance of not less than 1.5 MPa and a tensile strength of not less than 2 MPa. The number of grout outlet holes on a single grouting bladder assembly... and the number of grouting bags satisfy In this embodiment, the diameter of the slurry outlet is... Calculate using the following formula: ; in: The adjustment factor is set between 0.8 and 1.0. The density of the slurry; This refers to the grouting flow rate per single outlet hole. In this embodiment, a further preferred value is the grouting flow rate per single outlet hole. 0.05m can be taken. 3 / min-0.15m 3 / min; Number of overflow holes on a single grouting bladder assembly Preferably, there are 2-6 overflow holes, and the diameter of the overflow holes is preferred. With the diameter of the slurry outlet same.

[0055] The specific construction method for reinforcing railway subgrade structures using the bladder-type grouting method in this embodiment includes the following steps: Step 1: After the railway is subjected to earthquake, a comprehensive survey of the roadbed is conducted to identify the settlement zones, settlement amounts, and damage extent. The post-earthquake roadbed elevation is compared with the original design elevation using a total station or laser surveying equipment to determine the actual required roadbed uplift and reinforcement area. During the survey, benchmark points and monitoring points are also established in the grouting reinforcement sections to dynamically control the roadbed elevation and deformation throughout the construction process.

[0056] Step 2: Determine the layout scheme of the grouting lifting holes based on the settlement section and the extent of damage, including: ① For the grouting lifting holes, including the number of rows, depth, angle with the horizontal line, and location; ② For the grouting bags, including the quantity, size, shape, spacing, and installation position on the grouting section of the grouting pipe.

[0057] Step 3: Move the drilling rig to the drilling position, align it with the hole location, and use a spirit level to ensure the rig and drill rod are level. The inclination should not exceed 1%, and the deviation between the drilling position and the designed position should not exceed 50mm. Perpendicular to the roadway direction, drill a small-diameter hole horizontally or at the designed inclination from one side of the roadbed, to the designed depth. After drilling, clean the hole wall; if necessary, use a casing for stability and protection.

[0058] Step 4: After drilling is completed, lower the grouting bladder assembly to the predetermined position and adjust the grout outlet direction mark 16 so that the grouting bladder, after expansion, can lift the subgrade settlement or reinforce the damaged area of ​​the subgrade. The grouting bladder should preferably be made of high-strength geosynthetic material to ensure that it has sufficient tensile and puncture resistance during the grouting expansion process. After installation, the grouting bladder should be checked for sealing to ensure that the grout can be released directionally under the constraint of the grouting bladder during the grouting process, without grout leakage or runoff.

[0059] Step 5: Grout the grouting bladder assembly, starting with the area of ​​greatest settlement; this results in a bladder-type grouting reinforcement of the railway subgrade structure.

[0060] In this embodiment, before grouting, a monitoring system needs to be set up in the roadbed reinforcement section. A grouting pressure and grouting flow monitoring system is set up on the grouting device and connected to the data acquisition and feedback device to realize real-time monitoring of grouting pressure, flow and roadbed elevation changes. Once the monitoring data deviates significantly from the design target, the grouting flow or pressure can be adjusted in time to ensure the controllability and safety of the construction process.

[0061] In this preferred embodiment, the grouting construction is carried out in a segmented and phased manner. During the grouting and lifting process, the grouting sequence starts from the area with the largest settlement and gradually moves towards the area with the smallest settlement to avoid sudden uplift or local instability of the roadbed. After the grout is injected into the bladder through the pipeline, the bladder applies diffusion pressure to the surrounding soil during the pressure expansion process, forming a lifting effect and gradually restoring the elevation of the roadbed. After the grout solidifies, it achieves the reinforcement of the roadbed.

[0062] In this preferred embodiment, the elevation change, deformation amount, and deformation rate of the roadbed should be continuously monitored during the grouting process. If the monitored data exceeds the warning value, the grouting flow rate or pressure can be adjusted in a timely manner to ensure the controllability and safety of the construction process. When the roadbed elevation returns to the design target value, and the monitoring data indicates that the roadbed has formed a stable composite load-bearing structure, the electromagnetic control valve of the grout outlet should be immediately closed to stop grouting into the grouting bag. Then, the electromagnetic control valve of the overflow hole should be opened to allow grout to fill the grouting lifting hole. Finally, the grouting lifting hole should be sealed to prevent grout overflow and rainwater intrusion.

[0063] In this embodiment, quality inspection and effect evaluation of the construction section are required after grouting is completed. The inspection includes verification of roadbed elevation, testing of foundation bearing capacity, and quality inspection of the grouting reinforcement. If the inspection finds that the reinforcement in some areas is insufficient or the settlement has not been fully restored, secondary grouting can be carried out based on the monitoring results.

[0064] The technical solution of this embodiment achieves the following effects: Firstly, the railway subgrade reinforcement structure disclosed in this embodiment can precisely compensate for and lift subgrade settlement by injecting a specified volume of grout into the grouting bag through the control of the electromagnetic servo valve at the grout outlet. Secondly, the expansion of the grouting bag compresses the surrounding soil, densifying it to a certain extent. Furthermore, the solidified cement grout forms a composite subgrade structure with the subgrade filler, improving the stability of the subgrade. Compared with traditional subgrade reinforcement methods, this subgrade reinforcement structure enables refined control of subgrade settlement recovery and improves the bearing capacity of the subgrade, providing a new method for subgrade reinforcement.

[0065] The above description is merely a preferred embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural transformations made using the contents of the present invention's specification and drawings under the inventive concept of the present invention, or direct / indirect applications in other related technical fields, are included within the patent protection scope of the present invention.

Claims

1. A bladder-type grouting reinforcement structure for railway subgrade, characterized in that, This includes the roadbed (2) and the bladder-type grouting reinforcement components; The roadbed (2) is set on the foundation (1), and the roadbed (2) includes a roadbed slope (2.1); the roadbed (2) is provided with multiple rows of grouting lifting holes (7) that penetrate the roadbed slope (2.1) and are arranged along the roadbed line direction and / or the roadbed height direction. The bladder-type grouting reinforcement assembly includes a grouting bladder assembly (9) corresponding to the grouting lifting hole (7). The grouting bladder assembly (9) includes a grouting pipe (10) and a grouting bladder (13). The grouting pipe (10) has one or at least two grouting bladders (13) arranged along its length. The grouting pipe (10) is provided with a grout outlet (11), which is connected to the grouting bladder (13). A grout outlet valve (12) is provided at the grout outlet (11).

2. The bladder-type grouting reinforcement of railway subgrade structure according to claim 1, characterized in that, The extent of roadbed damage includes the length of the roadbed damaged along the route. Lateral width from the roadbed slope towards the centerline of the line Depth of damage to the roadbed and roadbed settlement .

3. The bladder-type grouting reinforcement of railway subgrade structure according to claim 2, characterized in that, Equivalent radius of reinforcement range of a single grouting bag Calculate using the following formula: ； in: The radius of the grouting bag, This refers to the vertical stress at the grouting lifting hole. The cohesion of the roadbed fill material, The internal friction angle of the roadbed fill material. The elastic modulus of the roadbed fill material. The Poisson's ratio of the roadbed fill material; Vertical stress at the grouting lifting hole Calculate using the following formula: ； in: For the first The unit weight of the subgrade fill material, For the first The thickness of the subgrade fill material, This refers to the total number of layers of subgrade fill material above the grouting lifting hole; Equivalent radius of reinforcement range of a single grouting bag Spacing between adjacent grouting lifting holes along the track direction The two should satisfy the following relationship: ； in: This represents the overlap coefficient of the reinforcement range along the route. Number of rows of grouting lifting holes along the track direction Calculate using the following formula: ； in: It is a rounding function; The spacing between adjacent grouting lifting holes along the roadbed depth direction is The two should satisfy the following relationship: ； in: This is the overlap coefficient of the reinforcement range along the depth direction of the roadbed; Number of rows of grouting lifting holes along the depth direction of the roadbed Calculate using the following formula: ； Total number of grouting lift holes within the subgrade damage area Satisfy the following expression: 。 4. The bladder-type grouting reinforcement of railway subgrade structure according to claim 3, characterized in that, Length of grouting lifting hole Calculate using the following formula: ； in: This refers to the vertical distance from the grouting lifting hole to the roadbed surface. The slope ratio of the roadbed side slope. The angle between the grouting lifting hole and the horizontal direction; The angle between the row of grouting lifting holes closest to the roadbed surface and the horizontal direction The vertical distance from the grouting lifting holes closest to the roadbed surface is 5°-10°. Not less than 2m.

5. The bladder-type grouting reinforcement of railway subgrade structure according to claim 3, characterized in that, Grouting pressure of a single grouting lift hole Calculate using the following formula: 。 6. The bladder-type grouting reinforcement of railway subgrade structure according to any one of claims 2-5, characterized in that, Total grouting volume required to raise the roadbed to the design elevation of the roadbed surface Calculate using the following formula: ； in: This is the grouting volume correction factor; The volume of grout injected into each grouting tube The calculation expression is as follows ; Number of grouting bladders on a single grouting bladder assembly Based on the volume of a single grouting bag and the volume of grout injected by a single grouting tube Sure: +1.

7. The bladder-type grouting reinforcement of railway subgrade structure according to claim 6, characterized in that, Length of grouting bladder assembly With the length of the grouting lifting hole Equal; the diameter of the grouting tube in the grouting bladder assembly. Diameter of the grouting lifting hole satisfy: ; Diameter of grouting bladder With roadbed settlement The following conditions must be met: , The first proportionality coefficient; Length of grouting bladder With roadbed settlement The following conditions must be met: , This is the second proportionality coefficient.

8. The bladder-type grouting reinforcement of railway subgrade structure according to claim 5, characterized in that, Number of grout outlet holes on a single grouting bladder assembly and the number of grouting bags equal; Diameter of slurry outlet Calculate using the following formula: ； in: For adjustment coefficients; The density of the slurry; This represents the grouting flow rate per single outlet hole.

9. The bladder-type grouting reinforcement of railway subgrade structure according to claim 8, characterized in that, The grouting pipe (10) is also provided with overflow holes (14), and the number of overflow holes on a single grouting bladder assembly is [number missing]. There are 2-6 overflow holes; the diameter of the overflow holes is... With the diameter of the slurry outlet same.

10. A construction method for reinforcing railway subgrade structures using bladder-type grouting as described in any one of claims 1-9, characterized in that, Includes the following steps: Step 1: Conduct a comprehensive survey of the roadbed to identify the settlement sections, settlement amounts, and damage ranges. Use a total station or laser measuring equipment to compare the post-earthquake roadbed elevation with the original design elevation to obtain the actual required roadbed uplift and reinforcement range. Step 2: Based on the settlement zone and the extent of damage, determine the layout scheme of the grouting lift holes. The layout scheme of the grouting lift holes includes: For grouting lifting holes, this includes the number of rows, depth, angle with the horizontal line, and location; For grouting bags, this includes the quantity, size, shape, spacing, and installation position on the grouting section of the grouting pipe; Step 3: Move the drilling rig to the drilling position and drill to obtain the grouting lifting hole; Step 4: Lower the grouting bladder assembly to the predetermined position and adjust the grout outlet direction mark so that the grouting bladder can lift the roadbed settlement or reinforce the damaged area of ​​the roadbed after it expands. Step 5: Grout the grouting bladder assembly, starting with the area of ​​greatest settlement; this results in a bladder-type grouting reinforcement of the railway subgrade structure.

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