Geosynthetic material wrapped gravel pile composite structure and construction method thereof

Abstract

The invention discloses a geosynthetic material wrapped gravel pile composite structure and a construction method thereof.The gravel pile composite structure comprises a geosynthetic material wrapping layer and a gravel pile body, the geosynthetic material wrapping layer is of an annular cylindrical barrel structure formed by geosynthetic materials, and the gravel pile body is of a cylinder structure formed by gravel; the geosynthetic material wrapping layer wraps the periphery of the gravel pile body. The reinforcing rings are uniformly arranged on the periphery of the geosynthetic material wrapping layer in a spiral shape, the reinforcing rings are fixedly connected with the geosynthetic material wrapping layer through steel bar binding, the fiber grating sensors are embedded into bent parts and straight section parts of the reinforcing rings at intervals, and the fiber grating sensors are used for collecting dynamic strain data of the gravel pile body in real time. The reinforcing ring provided by the invention can prevent lateral deformation of the geosynthetics wrapping layer and the gravel pile body, and the overall stability of the gravel pile composite structure in a complex stress environment is greatly improved.

Description

Technical Field

[0001] The present invention relates to the technical field of geotechnical engineering, and in particular to a geosynthetics-wrapped gravel pile composite structure and a construction method thereof. Background Art

[0002] In geotechnical engineering, foundation treatment is a key step in ensuring the safety and stability of engineering structures. With the acceleration of urbanization and the continuous advancement of infrastructure construction, engineering construction is facing increasingly complex geological conditions.

[0003] 1. Limitations of Traditional Gravel Piles: Due to their inherent structural characteristics, traditional gravel piles are prone to lateral deformation when subjected to loads, especially under extreme conditions such as strong earthquakes and high fills. This lateral deformation gradually intensifies over time and with increasing loads, ultimately leading to pile fracture and, in turn, foundation instability. For example, in construction projects in earthquake-prone areas, traditional gravel pile foundations experience significant lateral displacement and fracture in large numbers, resulting in excessive building foundation settlement and seriously compromising the safe operation of the structure.

[0004] 2. Disadvantages of gravel piles wrapped with geosynthetics: In order to improve the performance of gravel piles, the method of wrapping gravel piles with geosynthetics has been widely used. Although this method has improved the integrity of gravel piles to a certain extent, geosynthetics are prone to local tearing in harsh environments such as high-intensity earthquakes and high groundwater levels. This is because under the action of complex stresses, certain parts of geosynthetics will be subjected to excessive stress, forming stress concentration points. When the stress exceeds the ultimate strength of the material, tearing will occur. For example, in the treatment of soft soil foundations in coastal areas, due to the high groundwater level and high water content of the soil, gravel piles wrapped with geosynthetics are prone to local tearing of the material under long-term immersion and tidal effects, which greatly reduces the reinforcement effect of the foundation.

[0005] 3. Deficiencies of existing reinforcement methods: While some existing reinforcement methods, such as reinforcement with steel cage lining, have enhanced the strength of the pile to a certain extent, they also suffer from numerous drawbacks. For one thing, the production and installation of the steel cage requires a large amount of steel and labor, resulting in high costs. Furthermore, the construction process of the steel cage is complex, requiring multiple steps such as processing, tying, and lowering the steel bars, resulting in a long construction period. Furthermore, the synergy between the steel cage and geosynthetics is poor, preventing the full utilization of their respective strengths, making it difficult to achieve the desired reinforcement effect in actual projects. Summary of the Invention

[0006] To address the limitations and defects of the prior art, the present invention provides a geosynthetics-wrapped gravel pile composite structure based on a reinforcement ring, comprising: The gravel pile composite structure comprises a geosynthetic wrapping layer and a gravel pile body, wherein the geosynthetic wrapping layer is a circular cylindrical structure formed of geosynthetics, and the gravel pile body is a cylindrical structure formed of gravel, and the geosynthetic wrapping layer is wrapped around the outer periphery of the gravel pile body; The reinforcement ring is spirally and evenly arranged on the periphery of the geosynthetic material wrapping layer. The reinforcement ring is fixedly connected to the geosynthetic material wrapping layer by steel bar binding. The curved part and the straight part of the reinforcement ring are alternately embedded with fiber optic Bragg grating sensors. The fiber optic Bragg grating sensors are used to collect dynamic strain data of the gravel pile body in real time.

[0007] Optionally, the particle size range of the gravel is 5mm-40mm, wherein gravel with a particle size of 5mm-10mm accounts for 30%, gravel with a particle size of 10mm-20mm accounts for 40%, and gravel with a particle size of 20mm-40mm accounts for 30%.

[0008] Optionally, the geosynthetics include geogrids or geotextiles.

[0009] Optionally, the longitudinal tensile strength of the geogrid and the geotextile is not less than 100 kN / m, and the transverse tensile strength of the geogrid and the geotextile is not less than 100 kN / m.

[0010] Optionally, in areas with a seismic fortification intensity greater than or equal to 8 degrees and in building foundations with an importance level greater than or equal to a preset value, the tensile strength of the geogrid and the geotextile is not less than 200 kN / m; Under standard test conditions, the 1000-hour creep strain of the geogrid and the geotextile does not exceed 5%.

[0011] Optionally, the reinforcing ring is made of a polyester material, and the polyester material has a breaking strength ranging from 4 cN / dtex to 6 cN / dtex and a tensile strength ranging from 300 MPa to 500 MPa.

[0012] Optionally, the ratio of the spiral pitch of the reinforcement ring to the diameter of the gravel pile body is in a range of 1:5 to 1:10.

[0013] The present invention also provides a construction method of the geosynthetics-wrapped gravel pile composite structure based on the reinforcement ring, comprising: Using a theodolite and a level, calculating the coordinates of the gravel piles according to the design drawings, and measuring and marking the positions of the gravel piles at the construction site; A drilling operation is performed at the marked position of the gravel pile using a vibration pipe sinking method, an impact drilling method, or an auger drilling method; during the drilling process, the verticality, depth, and hole wall stability of the hole are monitored in real time by a drilling sensor, and drilling parameters are adjusted according to the verticality, depth, and hole wall stability; According to the diameter of the gravel pile body, the geosynthetics are pre-cut to form a circular cylindrical structure, so that the size of the circular cylindrical structure matches the gravel pile body; the reinforcement ring is fixed to the periphery of the geosynthetics by tying with steel bars, and the tying points are evenly distributed in a spiral shape; Synchronously placing the geosynthetics and the reinforcement ring at a predetermined construction location; Connecting one end of the transmission cable to the fiber Bragg grating sensor, connecting the other end of the transmission cable to a demodulator, connecting the output end of the demodulator to the input end of a data acquisition device, and connecting the output end of the data acquisition device to a computer; Using gravel filling equipment, according to the layered filling method, the gravel is evenly filled into the cylindrical cylinder structure formed by the geosynthetics; during the filling process, the gravel is vibrated and compacted using vibration equipment or compaction equipment, while the density of the gravel is monitored in real time through a pressure sensor. When the density of the monitored gravel reaches the preset density, the gravel filling is stopped; Using a tensioning tool, according to a preset tensioning force standard, uniformly apply tension along the circumference of the reinforcement ring, so that the reinforcement ring is tightly fitted to the geosynthetics wrapping layer and the gravel pile body; when the tensioning force of the reinforcement ring reaches the preset tensioning force, the reinforcement ring is fixed with a tying material, so that the reinforcement ring remains in a tensioned state; A crushed stone cushion layer is laid on the top of the crushed stone pile, geosynthetics are laid on the crushed stone cushion layer, and a backfill soil roadbed is formed on the geosynthetics.

[0014] Optionally, the thickness of the crushed stone cushion layer ranges from 300 mm to 500 mm.

[0015] Optionally, the compaction degree of the gravel cushion layer is greater than or equal to 90%.

[0016] The present invention has the following beneficial effects: 1. Improved Structural Stability: The dual constraint mechanism of the geosynthetics wrap and the reinforcement ring effectively limits the lateral deformation of the gravel pile, significantly improving the overall stability of the composite structure and the bearing capacity of the foundation, providing a solid foundation for the long-term stable operation of the project. Furthermore, the reinforcement ring increases the critical tear load of the geosynthetics by 2-3 times, making it more difficult for the geosynthetics wrap to tear under strong earthquakes. This further ensures the integrity and stability of the composite structure and provides a solid and reliable foundation for the safe use of buildings in earthquake-prone areas.

[0017] 2. Significant Economic Advantages: This invention demonstrates significant cost advantages over traditional steel cage solutions. Actual project calculations show that the composite structure of this invention can reduce costs by up to 35%. Furthermore, due to the use of high-strength, corrosion-resistant reinforcement ring materials, the corrosion resistance lifespan is ≥50 years. This significantly extends the service life of the structure compared to traditional solutions, reducing ongoing maintenance and replacement costs. From a lifecycle cost perspective, this approach offers exceptionally high cost-effectiveness.

[0018] 3. Real-time and accurate monitoring: The organic combination of the ring and fiber optic monitoring systems enables real-time and accurate monitoring of the working status of the composite structure. This enables timely identification of potential safety hazards, enabling engineers to take effective countermeasures in advance, greatly enhancing project safety.

[0019] 4. Optimization of construction quality and efficiency: During the construction process, the reinforcing rings and geosynthetics can be pre-tied, which not only improves construction efficiency, reduces the complicated steps of temporary assembly on site, shortens the construction period, but also reduces the impact of human factors on construction quality, ensuring the high standards and stability of project quality. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is a schematic structural diagram of a geosynthetics-wrapped gravel pile composite structure based on a reinforcement ring provided in Example 1 of the present invention.

[0021] Figure 2 This is a schematic diagram of the installation structure of the steel bar binding and fiber Bragg grating sensor provided in the first embodiment of the present invention.

[0022] Figure 3 This is a top view of a composite structure of gravel piles wrapped with geosynthetics based on reinforcement rings provided in Example 1 of the present invention.

[0023] Among them, 1-crushed stone; 2-geosynthetics; 3-reinforcement ring; 4-fiber Bragg grating sensor; 5-binding steel bars; 6-transmission cable; 7-crushed stone cushion; 8-backfill soil roadbed; 9-pavement; 10-demodulator; 11-data acquisition device; 12-computer. DETAILED DESCRIPTION

[0024] In order to enable those skilled in the art to better understand the technical solution of the present invention, the geosynthetics-wrapped gravel pile composite structure and the construction method thereof provided by the present invention are described in detail below with reference to the accompanying drawings. Example 1

[0025] This embodiment improves the overall performance of the foundation under complex geological conditions, particularly in seismically active areas, soft soil foundations, and high-fill foundations, by synergizing the spiral reinforcement ring with geosynthetics and crushed stone piles. The technology provided by this embodiment can be widely applied to various infrastructure construction projects, including construction projects, road and bridge projects, and port and terminal projects. It aims to address the problems of poor stability, insufficient durability, and low construction efficiency associated with traditional foundation treatment methods when faced with special geological conditions and complex working conditions.

[0026] This embodiment provides a composite structure of a geosynthetic-wrapped gravel pile based on a reinforcement ring. The wrapped gravel pile consists of a geosynthetic wrapping layer and well-graded gravel, and the pile diameter is determined according to engineering requirements. The geosynthetic wrapping layer is made of geogrid or geotextile and is wrapped around the periphery of the gravel pile body. The reinforcement ring is made of high-strength polyester material, spirally wrapped around the periphery of the geosynthetic, and connected to the geosynthetic by steel bar binding. The monitoring system senses the dynamic strain of the pile body in real time through the reinforcement ring embedded with a fiber optic Bragg grating sensor.

[0027] In this embodiment, the geosynthetics are geogrids or geotextiles, and their longitudinal and transverse tensile strengths should not be less than 100 kN / m, and they are wrapped in a circular shape around the periphery of the gravel pile. In areas with an earthquake fortification intensity of 8 degrees or above or in important building foundations, the tensile strength is not less than 200 kN / m, and under standard test conditions, the 1000-hour creep strain does not exceed 5%. The reinforcement ring is a stretchable high-strength polyester material, whose breaking strength is generally 4-6 cN / dtex and the tensile strength can reach 300-500 MPa, which can effectively withstand the large stress transmitted by the pile body under complex stress conditions. The high-strength polyester material has good tolerance to common chemicals such as acids and alkalis, and can be stably used in a variety of complex engineering environments to ensure the long-term effectiveness of the composite structure.

[0028] In this embodiment, the reinforcement ring is spiral-shaped, with a helical pitch to pile diameter ratio of 1:5-1:10. It is wrapped around the geosynthetic. The monitoring system uses the reinforcement ring, embedded with fiber Bragg grating sensors, to provide real-time dynamic strain monitoring of the pile. For spiral reinforcement rings, sensors can be placed at intervals along the bends and straight sections to comprehensively monitor the status of different locations.

[0029] In this embodiment, the wrapped gravel pile is composed of a geosynthetic wrapping layer and well-graded gravel, and the pile diameter is determined according to the engineering requirements; the geosynthetic wrapping layer adopts geogrid or geotextile, which is wrapped around the outer periphery of the gravel pile body; the reinforcement ring is made of high-strength polyester material, which is spirally wrapped around the outer periphery of the geosynthetic material and is connected to the geosynthetic material by steel bar binding; the monitoring system senses the dynamic strain of the pile body in real time through the reinforcement ring embedded with the fiber optic Bragg grating sensor.

[0030] In this embodiment, the geosynthetics are geogrids or geotextiles, and their longitudinal and transverse tensile strengths should not be less than 100 kN / m, and they are wrapped in a circular shape around the periphery of the gravel pile. In areas with an earthquake fortification intensity of 8 degrees or above or in important building foundations, the tensile strength is not less than 200 kN / m, and under standard test conditions, the 1000-hour creep strain does not exceed 5%. The reinforcement ring is a stretchable high-strength polyester material, whose breaking strength is generally 4-6 cN / dtex and the tensile strength can reach 300-500 MPa, which can effectively withstand the large stress transmitted by the pile body under complex stress conditions. The high-strength polyester material has good tolerance to common chemicals such as acids and alkalis, and can be stably used in a variety of complex engineering environments to ensure the long-term effectiveness of the composite structure.

[0031] In this embodiment, the reinforcement ring is spiral-shaped, with a helical pitch to pile diameter ratio of 1:5-1:10. It is wrapped around the geosynthetic. The monitoring system uses fiber grating (FBG) sensors embedded in the reinforcement ring to sense the dynamic strain of the pile. For spiral reinforcement rings, sensors can be placed at intervals along the bends and straight sections to comprehensively monitor the status of different locations.

[0032] This embodiment provides a composite structure of gravel piles wrapped in geosynthetics based on reinforcement rings, which effectively disperses seismic stress, inhibits the tearing of geosynthetics and the deformation of gravel piles, significantly improves the energy consumption capacity and ductility of the foundation, and at the same time reduces construction costs and improves construction efficiency, so as to meet the high-quality and high-performance requirements of modern engineering construction for foundation treatment. Example 2

[0033] This embodiment provides a construction method for a geosynthetics-wrapped gravel pile composite structure based on a reinforcement ring as described in the first embodiment, comprising the following steps: Surveying and setting out: Using conventional surveying instruments such as theodolites and levels, manually observing angles and elevation differences, calculating coordinates based on design drawings, and measuring and marking the positions of gravel piles at the construction site.

[0034] Hole Drilling: Holes are drilled at the marked locations using intelligently controlled drilling processes such as vibration sinking, impact drilling, or spiral drilling. During the drilling process, sensors monitor the verticality, depth, and wall stability of the holes in real time, feeding the data back to the control system to automatically adjust the drilling parameters.

[0035] Geosynthetics and reinforcement rings: Pre-cut and process the geosynthetics into circular rings based on the pile diameter, ensuring a precise fit. The reinforcement rings are then securely and evenly tied to the geosynthetics, with appropriate tie points to ensure a tight fit and prevent relative displacement.

[0036] Placement of geosynthetics and reinforcement rings: After completing the above-mentioned binding operations, the geosynthetics and reinforcement rings are placed as a whole, synchronously and accurately at the predetermined construction location. The placement process must strictly follow the construction design requirements to ensure that the placement is accurate and avoid deviation or misalignment, thus laying a good foundation for subsequent construction.

[0037] Circuit Construction: Connect one end of the transmission cable to the pre-processed fiber Bragg grating sensor embedded in the reinforcement ring, and the other end to the demodulator, ensuring a secure connection and good contact. After the circuit is connected, connect the demodulator output to the analog signal input channel of the data acquisition card. The data acquisition card is connected to the computer via a data cable, and data calibration and acquisition are performed simultaneously.

[0038] Filling with gravel: Gravel filling equipment is used to evenly fill well-graded gravel into the holes wrapped with geosynthetics using a layered filling method. During the filling process, the gravel is vibrated and compacted using vibration or compaction equipment, while the density of the gravel is monitored in real time through a pressure sensor. Filling is stopped when the designed density is reached.

[0039] Tensioning and securing the reinforcement ring: After the gravel filling reaches the design requirements, the reinforcement ring is tensioned. Using appropriate tensioning tools, and according to the tensioning force standards specified in the engineering design, uniform tension is applied along the circumference of the reinforcement ring to ensure a tight fit between the geosynthetics and the internal gravel pile, effectively restraining pile deformation. Once the predetermined tensioning force is reached, high-strength binding materials are used to securely secure the reinforcement ring in the tensioned state, preventing loosening or displacement during subsequent construction and use. This ensures the stability and load-bearing performance of the geosynthetics-encased gravel pile composite structure based on the reinforcement ring.

[0040] Pile top treatment: Treat the top of the gravel pile by laying a gravel cushion of a certain thickness and a layer of geosynthetics on the cushion to further enhance the integrity and bearing capacity of the composite foundation; use a compaction tester to test the area after the pile top treatment to ensure that the compaction meets the design requirements.

[0041] Real-time monitoring: During the pile construction process and after commissioning, the fiber optic transmission system collects data in real time. The pile is subjected to various stresses, which are transmitted to a computer via the fiber optic transmission system. The computer's data processing software displays the corresponding strain in real time based on pre-set parameters.

[0042] In this embodiment, the hole-forming equipment can automatically adjust construction parameters according to real-time monitoring data.

[0043] The construction method of the geosynthetics-wrapped gravel pile composite structure based on the reinforcement ring provided in this embodiment includes the following steps: (1) Surveying and laying out: Using conventional surveying instruments such as theodolite and level, manually observing angles and elevation differences, calculating coordinates based on design drawings, and measuring and marking the locations of gravel piles at the construction site.

[0044] (2) Hole forming: A hole forming process such as the vibration sinking pipe method, impact hole forming method or spiral drilling method with intelligent control is used to form a hole at the marked position. During the hole forming process, the verticality, depth and hole wall stability of the hole are monitored in real time by sensors, and the data is fed back to the control system to realize automatic adjustment of the hole forming parameters.

[0045] (3) Geosynthetics and reinforcement rings: According to the pile diameter, the geosynthetics are pre-cut and processed into a circular ring to ensure that the size accurately matches the pile. Subsequently, the reinforcement rings are tied to the periphery of the geosynthetics in a secure and uniform manner. The tying points should be reasonably distributed to ensure that the reinforcement rings are tightly bonded to the geosynthetics and that no relative displacement occurs.

[0046] (4) Placement of geosynthetics and reinforcement rings: After completing the above-mentioned binding operations, the geosynthetics and reinforcement rings are placed as a whole, synchronously and accurately at the predetermined construction location. The placement process must strictly follow the construction design requirements to ensure that the placement position is accurate and avoid deviation or misalignment, thus laying a good foundation for subsequent construction.

[0047] (6) Circuit Construction: Connect one end of the transmission cable to the pre-processed fiber Bragg grating sensor embedded in the reinforcing ring, and the other end to the demodulator, ensuring a secure connection and good contact. After the circuit is connected, connect the output of the demodulator to the analog signal input channel of the data acquisition card. The data acquisition card is connected to the computer via a data cable, and data calibration and acquisition are performed simultaneously.

[0048] (7) Filling with gravel: Use gravel filling equipment and layered filling method to evenly fill well-graded gravel into the holes wrapped with geosynthetics; during the filling process, use vibration or compaction equipment to vibrate and compact the gravel, and at the same time use pressure sensors to monitor the density of the gravel in real time. Stop filling when the designed density is reached.

[0049] (8) Tensioning and fixing of reinforcement ring: After the gravel filling is completed to the design requirements, the reinforcement ring is tightened. Use appropriate tensioning tools and apply tension evenly along the circumference of the reinforcement ring according to the tensioning force standard specified in the engineering design to ensure that the reinforcement ring fits tightly against the geosynthetics and the internal gravel pile body, effectively restraining the deformation of the pile body. After the predetermined tensioning force is reached, use high-strength binding materials to firmly fix the reinforcement ring in the tensioned state to prevent it from loosening or displacement during subsequent construction and use, thereby ensuring the stability and bearing performance of the geosynthetics-wrapped gravel pile composite structure based on the reinforcement ring.

[0050] (9) Pile top treatment: Treat the top of the gravel pile by laying a gravel cushion layer of a certain thickness and laying a layer of geosynthetics on the cushion layer to further enhance the integrity and bearing capacity of the composite foundation; use a compaction tester to test the area after the pile top treatment to ensure that the compaction meets the design requirements.

[0051] (10) Real-time monitoring: During the construction process and after the pile is put into use, the optical fiber transmission system collects data in real time. The pile is subjected to various stresses, which are transmitted to the computer via the optical fiber transmission system. The data processing software in the computer displays the corresponding strain in real time according to pre-set parameters.

[0052] 1. Material preparation Gravel Pile Material: Select well-graded gravel based on project design requirements. The gravel is rigorously screened to ensure a uniform particle size distribution that conforms to a specific gradation curve. For example, in a soft soil foundation treatment project, a particle size range of 5-40mm was selected, with 30% being 5-10mm, 40% 10-20mm, and 30% 20-40mm. This optimal gradation ensures that the gravel pile performs well in compacting the surrounding soil and transferring loads.

[0053] Geosynthetics: Geosynthetics must provide relevant quality inspection reports demonstrating their high strength and corrosion resistance. Laboratory sampling tests were conducted for tensile strength, water permeability, and self-sensing properties. Tensile strength testing was performed using a universal testing machine according to standard test methods, and the material's tensile strength exceeded 100 kN / m, meeting project requirements.

[0054] Reinforcement ring material: High-strength polyester material made of polyethylene terephthalate (PET) fiber is selected to make the reinforcement ring, and mechanical properties testing is carried out to ensure that its yield strength, tensile strength and other indicators meet the design requirements. Fiber Bragg grating sensors are embedded in the bending parts and straight sections of the reinforcement ring at intervals.

[0055] Its auxiliary materials: crushed stone cushion materials and geosynthetics prepared for pile top treatment, as well as related cleaning materials for cleaning equipment and sites.

[0056] 2. Equipment preparation Surveying equipment: Using conventional surveying instruments such as theodolites and levels, manually observing angles and elevation differences, calculating coordinates based on design drawings, and measuring and marking the locations of gravel piles at the construction site.

[0057] Drilling Equipment: If using the impact drilling method, use a percussion drill equipped with a hammer. Calibrate and test the percussion drill's impact force adjustment system and verticality monitoring device. If using the auger drilling method, use an auger drill with a torque of 120 kN·m. Inspect and maintain its drilling speed adjustment device and depth measurement device.

[0058] Prepare intelligent gravel filling equipment equipped with a pressure sensor and automatic control device that can automatically adjust the filling speed and volume based on the pressure sensor's feedback. Before use, calibrate the pressure sensor to ensure the accuracy of its measurement data.

[0059] Vibration and compaction equipment: A medium-sized vibrating pile driver with a power of 75-120kW and a vibration force of 300-600kN is required to ensure smooth sinking of the pile pipe into the foundation soil. Before use, the vibration performance of the equipment should be tested to ensure that it can effectively improve the density of the gravel.

[0060] Circuit Construction: Connect one end of the transmission cable to the pre-processed fiber Bragg grating sensor embedded in the reinforcement ring, and the other end to the demodulator, ensuring a secure connection and good contact. Be careful not to bend or stress the cable to ensure uninterrupted signal transmission. Protect the cable with a protective sleeve to prevent damage during construction. After connecting the circuit, connect the demodulator output to the analog signal input channel of the data acquisition card. The data acquisition card is then connected to the computer via a data cable.

[0061] Calibration and Initial Data Collection: The entire monitoring system is calibrated. By testing with a simulated load of a known signal, the data acquisition card's sampling parameters are adjusted to ensure the system can accurately measure resistance changes. After calibration, strain data from the fiber optic sensor in the pile's initial state is collected to serve as a baseline for subsequent monitoring.

[0062] 3. Implementation of the construction process Surveying and setting out: Using conventional surveying instruments such as theodolites and levels, the locations of the gravel piles are measured and marked at the construction site by manually observing angles and elevation differences and calculating coordinates based on the design drawings. During the surveying process, control points are set at regular intervals to verify the results. For example, within a 50m square site, control points are set every 10m to ensure that measurement errors are within the allowable range.

[0063] Hole Drilling: Move the vibrating pile driver to the marked position and adjust the verticality of the steel casing to within 1%. Start the vibrating pile driver and sink the steel casing into the ground at the preset vibration frequency and sinking speed. During the sinking process, sensors installed on the steel casing monitor the verticality, depth, and wall stability of the hole in real time. If signs of localized collapse of the hole wall are detected, the control system automatically adjusts the vibration frequency and sinking speed, slowing the sinking speed and appropriately increasing the vibration frequency to ensure hole quality. When the hole depth reaches the design requirement, sinking stops.

[0064] Geosynthetics and reinforcement rings: Pre-cut and process the geosynthetics into circular rings based on the pile diameter, ensuring a precise fit. The reinforcement rings are then securely and evenly tied to the geosynthetics, with appropriate tie points to ensure a tight fit and prevent relative displacement.

[0065] Placement of geosynthetics and reinforcement rings: After completing the above-mentioned binding operations, the geosynthetics and reinforcement rings are placed as a whole, synchronously and accurately at the predetermined construction location. The placement process must strictly follow the construction design requirements to ensure that the placement is accurate and avoid deviation or misalignment, thus laying a good foundation for subsequent construction.

[0066] Gravel filling: The gravel filling equipment is activated, and well-graded gravel is delivered to the hole via a conveying pipe. During the filling process, the vibrating or compacting equipment is simultaneously activated to vibrate and compact the gravel. Pressure sensors monitor the density of the gravel in real time. When the density reaches above 95% of the design requirement, the intelligent gravel filling equipment automatically reduces the filling speed until the design density is reached and stops filling. During the filling process, the operating parameters of the vibrating or compacting equipment, such as the excitation force and vibration time of the vibrating plate compactor, are adjusted according to actual conditions to ensure uniform density of the gravel.

[0067] Tensioning and securing the reinforcement ring: After the gravel filling reaches the design requirements, the reinforcement ring is tightened. Using appropriate tensioning tools, and according to the tensioning force standards specified in the engineering design, uniform tension is applied along the circumference of the reinforcement ring to ensure a tight fit between the geosynthetics and the internal gravel pile, effectively restraining pile deformation. Once the predetermined tensioning force is reached, the reinforcement ring is securely secured in place using reliable, high-strength lashing materials to prevent loosening or displacement during subsequent construction and use, thereby ensuring the stability and load-bearing performance of the geosynthetics-wrapped gravel pile composite structure based on the reinforcement ring.

[0068] Pile top treatment: A crushed stone cushion is laid on the top of the gravel pile. The thickness of the gravel cushion is determined according to the design requirements and is generally 300-500mm. The gravel is evenly laid on the pile top using a loader or manual labor. The crushed stone cushion is then compacted using a roller to a compaction level of at least 90%. A layer of geosynthetics is laid on top of the compacted gravel cushion, using the same method as before, ensuring that the geosynthetics are flat and closely adhere to the gravel cushion.

[0069] Real-time monitoring: During the pile construction process and after commissioning, the fiber optic transmission system collects data in real time. The pile is subjected to various stresses, which are transmitted to a computer via the fiber optic transmission system. The computer's data processing software displays the corresponding strain in real time based on pre-set parameters.

[0070] This embodiment provides a construction method for a geosynthetic-wrapped gravel pile composite structure based on a reinforcement ring. The gravel pile composite structure includes a geosynthetic wrap layer and a gravel pile body. The geosynthetic wrap layer is a circular cylindrical structure formed of geosynthetics, and the gravel pile body is a cylindrical structure formed of gravel. The geosynthetic wrap layer is wrapped around the periphery of the gravel pile body. The reinforcement ring is spirally and evenly arranged around the periphery of the geosynthetic wrap layer. The reinforcement ring is fixedly connected to the geosynthetic wrap layer by steel bar binding. Fiber grating sensors are embedded in the curved and straight sections of the reinforcement ring at intervals. The fiber grating sensors are used to collect dynamic strain data of the gravel pile body in real time. The reinforcement ring provided in this embodiment can prevent lateral deformation of the geosynthetic wrap layer and the gravel pile body, greatly improving the overall stability of the gravel pile composite structure under complex stress environments. The technical solution provided in this embodiment can disperse stress, avoid local stress concentration that damages the gravel pile composite structure, effectively improve foundation stability, and has broad application prospects.

[0071] It will be understood that the above embodiments are merely exemplary embodiments for illustrating the principles of the present invention, and the present invention is not limited thereto. Those skilled in the art will appreciate that various modifications and improvements can be made without departing from the spirit and substance of the present invention, and such modifications and improvements are also considered to be within the scope of protection of the present invention.

Claims

1. A geosynthetic-wrapped gravel pile composite structure based on a reinforcement ring, characterized in that: include: The gravel pile composite structure comprises a geosynthetic wrapping layer and a gravel pile body, wherein the geosynthetic wrapping layer is a circular cylindrical structure formed of geosynthetics, and the gravel pile body is a cylindrical structure formed of gravel, and the geosynthetic wrapping layer is wrapped around the outer periphery of the gravel pile body; The reinforcement ring is spirally and evenly arranged on the periphery of the geosynthetic material wrapping layer. The reinforcement ring is fixedly connected to the geosynthetic material wrapping layer by steel bar binding. The curved part and the straight part of the reinforcement ring are alternately embedded with fiber optic Bragg grating sensors. The fiber optic Bragg grating sensors are used to collect dynamic strain data of the gravel pile body in real time.

2. The geosynthetics-wrapped gravel pile composite structure based on reinforcement rings according to claim 1, characterized in that: The particle size range of the gravel is 5mm-40mm, among which the gravel with a particle size of 5mm-10mm accounts for 30%, the particle size of 10mm-20mm accounts for 40%, and the particle size of 20mm-40mm accounts for 30%.

3. The geosynthetics-wrapped gravel pile composite structure based on reinforcement rings according to claim 2, characterized in that: The geosynthetics include geogrids or geotextiles.

4. The geosynthetics-wrapped gravel pile composite structure based on reinforcement rings according to claim 3, characterized in that: The longitudinal tensile strength of the geogrid and the geotextile is not less than 100 kN / m, and the transverse tensile strength of the geogrid and the geotextile is not less than 100 kN / m.

5. The geosynthetics-wrapped gravel pile composite structure based on reinforcement rings according to claim 4, characterized in that: In areas with a seismic fortification intensity greater than or equal to 8 degrees and in building foundations with an importance level greater than or equal to a preset value, the tensile strength of the geogrid and the geotextile shall not be less than 200 kN / m; Under standard test conditions, the 1000-hour creep strain of the geogrid and the geotextile does not exceed 5%.

6. The geosynthetics-wrapped gravel pile composite structure based on reinforcement rings according to claim 5, characterized in that: The reinforcing ring is made of a polyester material, and the polyester material has a breaking strength ranging from 4 cN / dtex to 6 cN / dtex and a tensile strength ranging from 300 MPa to 500 MPa.

7. The geosynthetics-wrapped gravel pile composite structure based on reinforcement rings according to claim 6, characterized in that: The ratio of the spiral pitch of the reinforcement ring to the diameter of the gravel pile body is in a range of 1:5 to 1:

10.

8. A construction method of a geosynthetics-wrapped gravel pile composite structure based on a reinforcement ring according to any one of claims 1 to 7, characterized in that: include: Using a theodolite and a level, calculating the coordinates of the gravel piles according to the design drawings, and measuring and marking the positions of the gravel piles at the construction site; A drilling operation is performed at the marked position of the gravel pile using a vibration pipe sinking method, an impact drilling method, or an auger drilling method; during the drilling process, the verticality, depth, and hole wall stability of the hole are monitored in real time by a drilling sensor, and drilling parameters are adjusted according to the verticality, depth, and hole wall stability; According to the diameter of the gravel pile body, the geosynthetics are pre-cut to form a circular cylindrical structure, so that the size of the circular cylindrical structure matches the gravel pile body; the reinforcement ring is fixed to the periphery of the geosynthetics by tying with steel bars, and the tying points are evenly distributed in a spiral shape; Synchronously placing the geosynthetics and the reinforcement ring at a predetermined construction location; Connecting one end of the transmission cable to the fiber Bragg grating sensor, connecting the other end of the transmission cable to a demodulator, connecting the output end of the demodulator to the input end of a data acquisition device, and connecting the output end of the data acquisition device to a computer; Using gravel filling equipment, according to the layered filling method, the gravel is evenly filled into the cylindrical cylinder structure formed by the geosynthetics; during the filling process, the gravel is vibrated and compacted using vibration equipment or compaction equipment, while the density of the gravel is monitored in real time through a pressure sensor. When the density of the monitored gravel reaches the preset density, the gravel filling is stopped; Using a tensioning tool, according to a preset tensioning force standard, uniformly apply tension along the circumference of the reinforcement ring, so that the reinforcement ring is tightly fitted to the geosynthetics wrapping layer and the gravel pile body; when the tensioning force of the reinforcement ring reaches the preset tensioning force, the reinforcement ring is fixed with a tying material, so that the reinforcement ring remains in a tensioned state; A crushed stone cushion layer is laid on the top of the crushed stone pile, geosynthetics are laid on the crushed stone cushion layer, and a backfill soil roadbed is formed on the geosynthetics.

9. The construction method of the geosynthetics-wrapped gravel pile composite structure based on reinforcement rings according to claim 8, characterized in that: The thickness of the crushed stone cushion layer ranges from 300 mm to 500 mm.

10. The construction method of the geosynthetics-wrapped gravel pile composite structure based on reinforcement rings according to claim 9, characterized in that: The compaction degree of the crushed stone cushion layer is greater than or equal to 90%.

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