A kind of active slurry-based existing lake railway subgrade frost heaving thawing sinking suppression system

Abstract

The utility model relates to a kind of inhibition system of existing lake-surrounding railway subgrade frost heaving thawing sinking based on active slurry, and the system includes grouting pipeline embedded in subgrade soil body, grouting device placed on surface and communicated with the grouting pipeline and control monitoring unit being connected with the grouting pipeline outside the grouting device.The grouting pipeline is evenly distributed with multiple grouting small holes along length direction;The grouting device includes biological liquid supply unit and cementing solution supply unit connected together by grouting pump, and the biological liquid supply unit and cementing solution supply unit are communicated with the grouting pipeline respectively;One end of the grouting pump is connected with injection pipeline, and the injection pipeline is connected with the grouting pipeline.The utility model has the characteristics of uniform and continuous grouting, enhancing the ability of subgrade frost resistance, and is suitable for existing railway seasonal frozen soil area subgrade frost heaving control of Qinghai-Tibet Railway lake-surrounding section.

Description

Technical Field

[0001] This utility model relates to the fields of civil engineering and foundation reinforcement, and in particular to an existing frost heave and thaw settlement inhibition system for the subgrade of a lakeside railway based on active grout. Background Technology

[0002] The Qinghai-Tibet Plateau region is characterized by high altitude and cold climate, with widespread seasonal permafrost. The existing ring railway subgrade freezes in winter and suffers from frost heave during spring thawing, leading to subgrade uplift, cracking, and frequent other defects, severely impacting operational safety and maintenance costs. Traditional remediation methods often involve manual soil replacement, adding crushed stone, installing insulated pipes, or passive cooling systems.

[0003] However, these methods often have drawbacks such as long construction time, high cost, high energy consumption, or significant impact on the plateau ecological environment. For example, traditional drilling grouting can only inject curing agent in limited locations, resulting in insufficient grouting range and uniformity, making it difficult to comprehensively reinforce a wide-area roadbed. Furthermore, commonly used cement or chemical solution grouting materials can cause environmental pollution during use, which is detrimental to the ecological protection of the railway surrounding area. In recent years, active grout technology has attracted attention as a green and sustainable foundation solidification method. Studies have shown that active grout grouting can significantly improve soil impermeability and inhibit frost heave. This technology utilizes biological processes to generate calcite in situ within the soil, primarily filling soil pores and cementing soil particles, significantly enhancing soil strength and stability while reducing pore water content. The frost heave rate of soil treated with active grout technology is significantly reduced, and this technology uses environmentally friendly carbon sources and biological materials, making it more eco-friendly than traditional chemical grouting.

[0004] However, existing active grouting methods mostly employ point drilling or probe-type grouting, which limits the grouting range and easily leads to uneven sediment distribution. The lack of a uniform and continuous grouting method results in inconsistent distribution of mineralized products within the soil, affecting the overall frost heave resistance. Therefore, a new grouting system is needed to improve the application of active grouts in wide roadbeds. Utility Model Content

[0005] The technical problem to be solved by this utility model is to provide an existing frost heave and thaw settlement inhibition system for the subgrade of the lakeside railway, which is based on active grout and provides uniform and continuous grouting to enhance the frost heave resistance of the subgrade.

[0006] To address the aforementioned problems, this utility model discloses a frost heave and thaw settlement inhibition system for existing ring-lake railway subgrade based on active grout. The system comprises: a grouting pipe buried in the subgrade soil; a grouting device placed on the ground surface and connected to the grouting pipe; and a control and monitoring unit located outside the grouting device and connected to the grouting pipe. The grouting pipe has multiple grouting holes evenly distributed along its length. The grouting device includes a biological fluid supply unit and a cementing solution supply unit connected together via a grouting pump, both of which are connected to the grouting pipe. One end of the grouting pump is connected to an injection pipe, which is connected to the grouting pipe.

[0007] The grouting pipeline consists of several horizontally arranged main pipes connected together and several branch pipes perpendicular to the main pipes; one end of each main pipe is connected to the injection pipeline; several small grouting holes are evenly distributed on each branch pipe; one end of each main pipe is connected to the injection pipeline via a connector, and the other end extends to the required grouting end and is then sealed; a sensor pipe section with three internal thread interfaces is provided at the connection between the main pipe and the branch pipe, and a valve sensor, pressure sensor, and flow sensor corresponding to the three internal thread interfaces are provided in this sensor pipe section; the cables of the valve sensor, pressure sensor, and flow sensor pass through a waterproof plastic pipe and are led to the surface inspection well through a pre-reserved sealing wiring hole in the pipe wall; all three internal thread interfaces are sealed with O-rings and lock nuts; the valve sensor, pressure sensor, and flow sensor are respectively connected to the control and monitoring unit.

[0008] The grouting holes are evenly distributed along the pipe axis at a preset spacing.

[0009] The pressure sensor and the flow sensor are respectively located on the upper and lower sides of the valve sensor.

[0010] The injection pipeline is equipped with a main valve, which is electrically connected to the control and monitoring unit.

[0011] The control and monitoring unit includes an edge control module, a cloud server, a cloud monitoring platform, and an automatic algorithm control module. The edge control module is electrically connected to the valve sensor, pressure sensor, and flow sensor, respectively, and is electrically connected to the cloud server through a communication gateway. The cloud server is electrically connected to the cloud monitoring platform, and the cloud monitoring platform is electrically connected to the automatic algorithm control module.

[0012] This utility model has the following advantages compared with the prior art: 1. This utility model utilizes a network of interconnected grouting pipes with uniformly distributed grouting holes buried beneath the roadbed. This creates a continuous linear-surface grouting source, which, compared to traditional single-point drilling grouting, allows for the continuous injection of biological fluid and cementing solution into the roadbed soil. This induces the formation of widely distributed calcite in the soil pores, resulting in more uniform grouting, wider coverage, and a more consistent distribution of calcite within the soil. This effectively reduces the risk of localized frost heave and enhances the roadbed's resistance to frost heave. Furthermore, compared to single-point grouting, this utility model's continuous grouting via buried pipes significantly improves operational efficiency.

[0013] 2. The present invention is equipped with a control and monitoring unit, which makes it easy to realize automated control and grouting in sections and zones of the pipeline grouting system, reducing the number of repeated pipe laying and excavation, thereby effectively reducing construction time and labor costs.

[0014] 3. This utility model deploys pressure and flow sensors at key nodes of the pipeline system and connects them to the cloud platform through an industrial Internet of Things gateway to achieve the purpose of real-time collection of grouting data.

[0015] 4. This utility model is simple and easy to implement, and is applicable to the frost heave treatment of roadbeds in seasonally frozen soil areas of existing railways such as the Qinghai-Tibet Railway loop section. Attached Figure Description

[0016] The specific embodiments of this utility model will be further described in detail below with reference to the accompanying drawings.

[0017] Figure 1 This is a schematic diagram of the overall layout of this utility model.

[0018] Figure 2 This is a schematic cross-sectional view of the grouting pipe structure in this utility model.

[0019] Figure 3 This is a schematic diagram of the integrated grouting system formed by multiple grouting pipes in this utility model.

[0020] Figure 4 This is a schematic diagram of the control and monitoring unit in this utility model.

[0021] Figure 5 This invention relates to the pipeline grouting process.

[0022] Figure 6 This is a schematic diagram illustrating the mechanism by which the active slurry of this invention inhibits frost heave and thaw settlement in soil samples.

[0023] In the diagram: 1—Subgrade soil; 2—Control and monitoring unit; 3—Grouting hole; 4—Grouting pump; 5—Bio-liquid supply unit; 6—Cementing solution supply unit; 7—Injection pipe; 8—Main pipe; 9—Branch pipe; 10—Valve sensor; 11—Pressure sensor; 12—Flow sensor; 13—Main valve; 14—Edge control module; 15—Cloud server; 16—Cloud monitoring platform; 17—Automatic algorithm control module; 18—Communication gateway. Detailed Implementation

[0024] like Figures 1-4 As shown, an existing railway subgrade frost heave and thaw settlement inhibition system based on active grout is provided. The system includes a grouting pipe buried in the subgrade soil 1, a grouting device placed on the ground surface and connected to the grouting pipe, and a control and monitoring unit 2 located outside the grouting device and connected to the grouting pipe.

[0025] The grouting pipe has multiple grouting holes 3 evenly distributed along its length. The grouting device includes a biological liquid supply unit 5 and a cementing solution supply unit 6 connected together by a grouting pump 4. The biological liquid supply unit 5 and the cementing solution supply unit 6 are respectively connected to the grouting pipe and are used to inject biological liquid and cementing solution into the grouting pipe to induce the formation of calcite in the subgrade soil 1. One end of the grouting pump 4 is connected to an injection pipe 7, which is connected to the grouting pipe and is used to inject biological liquid and cementing solution into the grouting pipe respectively.

[0026] The grouting pipeline consists of several horizontally connected main pipes 8 and several branch pipes 9 perpendicular to the main pipes 8; one end of each main pipe 8 is connected to the injection pipeline 7; several small grouting holes 3 are evenly distributed on the branch pipes 9; one end of each main pipe 8 is connected to the injection pipeline 7 via a connector, and the other end extends to the required grouting end and is then sealed; a sensor pipe section with three internal thread interfaces is provided at the connection between the main pipe 8 and the branch pipe 9, and a valve sensor 10, a pressure sensor 11, and a flow sensor 12 corresponding to the three internal thread interfaces are provided in this sensor pipe section; the cables of the valve sensor 10, pressure sensor 11, and flow sensor 12 pass through a waterproof plastic pipe and are led to the surface inspection well through a pre-reserved sealing wiring hole in the pipe wall; all three internal thread interfaces are sealed with O-rings and lock nuts; the valve sensor 10, pressure sensor 11, and flow sensor 12 are respectively connected to the control and monitoring unit 2.

[0027] The grouting holes 3 are evenly distributed along the axial direction of the pipeline according to the preset spacing to ensure that the grout is discharged evenly in the axial and radial directions.

[0028] Pressure sensor 11 and flow sensor 12 are respectively located on the upper and lower sides of valve sensor 10.

[0029] A main valve 13 is provided on the injection pipe 7. The main valve 13 is electrically connected to the control and monitoring unit 2, but a manual device is still retained to prevent accidents.

[0030] The main pipe 8 has a diameter of approximately 100mm, and the branch pipe 9 has a diameter of approximately 50~80mm. Both are made of cold-resistant and corrosion-resistant materials, such as low-temperature resistant high-density polyethylene pipe or galvanized steel pipe.

[0031] The control and monitoring unit 2 is used to monitor parameters such as pressure, flow rate, and temperature during the grouting process in real time and adjust the grouting rate. It includes an edge control module 14, a cloud server 15, a cloud monitoring platform 16, and an automatic algorithm control module 17. The edge control module 14 is electrically connected to the valve sensor 10, pressure sensor 11, and flow sensor 12, respectively. The edge control module 14 is electrically connected to the cloud server 15 through a communication gateway 18. The cloud server 15 is electrically connected to the cloud monitoring platform 16 and can upload data to the cloud monitoring platform 16 for comparison in real time. The cloud monitoring platform 16 performs data analysis and is electrically connected to the automatic algorithm control module 17.

[0032] like Figure 5 As shown, the pipeline grouting process using the system described in this utility model is as follows: (1) Geological exploration and data collection: A geological survey was conducted on the section of road to be treated to determine the depth of the frozen soil and the distribution range of the disease.

[0033] (2) Pipeline layout design: The pipeline layout plan is designed based on the morphology of the diseased area, and the location of buried pipes and the pipeline network structure are planned.

[0034] (3) Experimental Samples and Proportioning Experiments - Preparation of Biological Fluid and Cementing Solution: Prepare the biological strains and culture medium, and after cultivation, load them into the biological liquid supply unit 5; at the same time, prepare the cementing solution supply unit 6.

[0035] (4) Drilling / grooving and laying the main pipe 8 and branch pipe 9: Drill holes or excavate trenches below the frost line along the centerline or both sides of the roadbed, and lay the main grouting pipe 8 horizontally downwards. At regular intervals, connect it to longitudinal branch pipes 9 via fittings to form a grid-like pipe network. Small grouting holes 3 with a diameter of 1-3 mm are evenly distributed on the pipe wall as grouting outlets. One end of the pipe is connected to the ground grouting device via a joint, and the other end is extended to the required grouting end and then sealed.

[0036] During pipe laying, at the connection point between the main pipe 8 and the branch pipe 9 in the subgrade soil 1, a pre-welded sensor pipe section of the same material as the main pipe 8 with three internal threaded interfaces is replaced. First, the valve sensor 10 with the valve is tightened and kept closed. Then, the pressure sensor 11 and flow sensor 12 are screwed in sequentially, and the interfaces are sealed with O-rings and lock nuts. The sensor cable is threaded into a waterproof plastic pipe and led to the surface inspection well through a pre-drilled sealed wiring hole in the pipe wall. Before backfilling, gravel is laid around the pipe and covered with clay to form a mud-retaining filter layer.

[0037] (5) Perform system-wide flushing and pressure testing using standard procedures.

[0038] ⑹ Connect to the ground grouting pump station control and monitoring unit 2.

[0039] (7) Start the grouting circulation: Under warm-season conditions, the grouting procedure is initiated from control and monitoring unit 2, and grouting pump 4 injects biological liquid and cementing solution into the pipeline network according to a set ratio. During the grouting process, the mixture seeps into the surrounding soil through small holes in the pipe wall.

[0040] Grouting is carried out in stages: each stage involves grouting for several hours, followed by pump shutdown for several hours to a full day, allowing the bio-slurry to generate calcite in the soil. Several grouting cycles are repeated as needed to ensure a continuous calcite layer is formed throughout the entire pipeline coverage area. During the grouting process, pressure sensor 11 and flow sensor 12 monitor the grouting status of each pipeline group in real time, transmitting the data to the control and monitoring unit 2 to promptly adjust valve sensor 10 to prevent pipeline blockage or uneven distribution.

[0041] (8) Monitoring data processing and effect evaluation: During the grouting process, pressure sensor 11 and flow sensor 12 continuously collect data and upload it to control and monitoring unit 2. The edge control module 14 in control and monitoring unit 2 uploads the data to cloud server 15 through communication gateway 18. Cloud server 15 collects and summarizes the data and uploads it to cloud monitoring platform 16 for comparison. After analysis by cloud server 16, automatic algorithm control module 17 adjusts the grouting rate and pressure as needed to ensure uniform grouting.

[0042] After grouting is completed, the injection volume and return flow are compared and a short-term pressure holding is performed to confirm that there is no grout leakage. Then, the permeability coefficient or wave velocity is measured on site to ensure that the permeability is reduced by at least one order of magnitude and the wave velocity is increased by about 30%. A small number of samples are drilled to test the strength and calcium carbonate content to verify whether the reinforcement skeleton has been formed. Then, the buried pressure sensor 11 and flow sensor 12 are activated to observe the changes in the pressure difference and flow rate in the pipe for one month. The ground settlement is checked with a total station or InSAR. If all indicators are stable and meet the design limits, it indicates that the grouting is uniform and the reinforcement is effective. Otherwise, grouting should be added or repaired in time.

[0043] like Figure 6 As shown, the unreinforced sample had large pores and loose soil particles. After reinforcement with active grout, the pores decreased, the density increased, and calcite crystals cemented the pores, forming a stable mineral framework within them. When the temperature drops and freezing occurs, ice crystals grow, reducing cracks and thus inhibiting the "freeze-thaw settlement" deformation. When the temperature rises and thawing occurs, meltwater slowly drains through only a few fine pores, and the calcite-soil particle mineral framework remains intact, keeping the sample volume almost unchanged. This avoids the collapse and instability that commonly occur in conventional soils during the thawing settlement stage.

[0044] It can be seen that after adopting the system described in this utility model, the moisture content of the subgrade soil 1 is reduced, and the shear strength and density are significantly improved, thereby significantly enhancing the subgrade's resistance to frost heave.

Claims

1. A system for inhibiting frost heave and thaw settlement of existing railway subgrade around a lake based on active slurry, characterized in that: The system includes a grouting pipe buried in the roadbed soil (1), a grouting device placed on the ground surface and connected to the grouting pipe, and a control and monitoring unit (2) located outside the grouting device and connected to the grouting pipe; the grouting pipe has a plurality of grouting holes (3) evenly distributed along its length; the grouting device includes a biological liquid supply unit (5) and a cementing solution supply unit (6) connected together by a grouting pump (4), the biological liquid supply unit (5) and the cementing solution supply unit (6) being connected to the grouting pipe respectively; one end of the grouting pump (4) is connected to an injection pipe (7), the injection pipe (7) being connected to the grouting pipe.

2. The frost heave and thaw settlement inhibition system for existing ring-lake railway subgrade based on active slurry as described in claim 1, characterized in that: The grouting pipeline consists of several horizontally arranged main pipes (8) connected together and several branch pipes (9) perpendicular to the main pipes (8); one end of each main pipe (8) is connected to the injection pipeline (7); several grouting holes (3) are evenly distributed on each branch pipe (9); one end of each main pipe (8) is connected to the injection pipeline (7) via a connector, and the other end extends to the required grouting end and is then sealed; a sensor pipe section with three internal thread interfaces is provided at the connection between the main pipe (8) and the branch pipe (9), and the sensor pipe section is equipped with three internal thread interfaces. Each of the three internal threaded interfaces corresponds to a valve sensor (10), a pressure sensor (11), and a flow sensor (12); the cables of the valve sensor (10), the pressure sensor (11), and the flow sensor (12) pass through a waterproof plastic pipe and are led to the surface inspection well through a pre-reserved sealing wiring hole in the pipe wall; all three internal threaded interfaces are sealed with O-rings and lock nuts; the valve sensor (10), the pressure sensor (11), and the flow sensor (12) are respectively connected to the control and monitoring unit (2).

3. The frost heave and thaw settlement inhibition system for existing ring-lake railway subgrade based on active slurry as described in claim 2, characterized in that: The grouting holes (3) are evenly distributed along the axial direction of the pipeline at a preset spacing.

4. The frost heave and thaw settlement inhibition system for existing ring-lake railway subgrade based on active slurry as described in claim 2, characterized in that: The pressure sensor (11) and the flow sensor (12) are respectively located on the upper and lower sides of the valve sensor (10).

5. The frost heave and thaw settlement inhibition system for existing ring-lake railway subgrade based on active slurry as described in claim 1, characterized in that: The injection pipe (7) is equipped with a main valve (13), which is electrically connected to the control and monitoring unit (2).

6. The frost heave and thaw settlement inhibition system for existing ring-lake railway subgrade based on active slurry as described in claim 1, characterized in that: The control and monitoring unit (2) includes an edge control module (14), a cloud server (15), a cloud monitoring platform (16), and an automatic algorithm control module (17). The edge control module (14) is electrically connected to the valve sensor (10), the pressure sensor (11), and the flow sensor (12), respectively. The edge control module (14) is electrically connected to the cloud server (15) through a communication gateway (18). The cloud server (15) is electrically connected to the cloud monitoring platform (16), and the cloud monitoring platform (16) is electrically connected to the automatic algorithm control module (17).

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