Improved intelligent control method for subgrade settlement at excavated and filled soil junction
By optimizing the combination of perforated geocell structure and self-sensing piezoelectric geocable, the problem of uneven settlement of roadbed at the junction of excavation and filling was solved, enabling real-time monitoring and intelligent control, and improving the bearing capacity and settlement early warning capability of the roadbed.
Patent Information
- Application Number
- CN202511079137.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-08-02
- Publication Date
- 2025-10-28
AI Technical Summary
Uneven settlement of the roadbed at the junction of excavation and filling soil leads to road surface cracking and structural damage. Existing technologies lack real-time monitoring and control methods, and water seepage during long-term service of geocells weakens the reinforcement effect.
The open geocells, made of high-density polyethylene (HDPE) material, have a pore size of 10mm and an open area ratio of 26.51%. They are arranged in a 'plum blossom' pattern and are combined with self-sensing piezoelectric geocells (SPGC) for real-time monitoring. Intelligent control and early warning are achieved through changes in impedance and voltage signals.
It significantly enhances the integrity and bearing capacity of the roadbed at the cut-fill junction, reduces uneven settlement, enables real-time monitoring and intelligent early warning of potential settlement problems, and reduces monitoring costs.
Smart Images
Figure CN120844636A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the technical field of road engineering, and in particular to an improved intelligent control method for roadbed settlement at the junction of cut and fill soil. Background Technology
[0002] The boundary between cut and fill sections is a weak point in roadbed engineering. Due to the significant difference in soil properties between the fill and cut areas, uneven settlement is prone to occur, leading to problems such as pavement cracking and structural damage. Traditional treatment methods mainly rely on measures such as layered compaction and setting transition sections, but lack the ability to monitor and control settlement deformation in real time.
[0003] In recent years, geosynthetics have been widely used in roadbed engineering. Geocells are a new type of flexible reinforcement material. Visually, they have a mesh-like three-dimensional structure. When implanted into the soil, they form a flexible composite with high stiffness. Due to the special structure of the geocell and the difference in modulus between the geocell and the soil, the geocell exerts friction and lateral restraint effects on the soil, enhancing its bearing capacity. However, during long-term service, water seepage into traditional geocells can cause the geocell strips to loosen, weakening their reinforcement effect. Furthermore, existing technologies lack real-time monitoring methods for the internal deformation and stress state of the roadbed, making it difficult to detect and warn of potential settlement problems in a timely manner. Due to limitations in technology, cost, and application scenarios, no distributed real-time monitoring technology for embankment internal deformation has yet been fully implemented for large-scale application. Summary of the Invention
[0004] The purpose of this invention is to overcome the shortcomings of the prior art and to provide an improved intelligent control method for roadbed settlement at the cut-fill junction by optimizing the structural parameters of the perforated geocell and combining it with a self-sensing piezoelectric geocable SPGC monitoring system.
[0005] The objective of this invention is achieved through the following technical solution: an improved intelligent control method for roadbed settlement at the cut-fill junction, comprising the following steps; S1. Selection and optimization of perforated geocells: Geocells made of high-density polyethylene (HDPE) are selected. The geocell height is 100mm, the thickness is 1.0mm, the welding distance is 330mm, and circular holes with a diameter of 10mm are opened on the geocell strips. The perforation rate is 26.51%, and the holes are arranged in a "plum blossom" pattern with a spacing of 20mm. S2. Based on the embankment height and load conditions, lay multiple layers of perforated geocells in the compression zone at the cut-fill junction. S3. Deployment of self-sensing piezoelectric geocable SPGC: Self-sensing piezoelectric geocable SPGC with a diameter of 2.7mm is deployed in layers along the longitudinal direction of the roadbed at the cut-fill junction. The positive and negative terminals of the self-sensing piezoelectric geocable SPGC are connected to the data acquisition box respectively to monitor the changes in impedance and voltage signals in real time. The shear displacement-normalized impedance relationship can be established through a bilinear model to quantify the soil strain information. S4. Intelligent monitoring and feedback control: The impedance and voltage signals of the self-sensing piezoelectric geocell (SPGC) are transmitted to the background computer in real time through a remote automated wireless transmission station to analyze the normalized impedance inflection point value and effective voltage change. When a significant drop in normalized impedance or abnormal voltage signal is detected, an early warning mechanism is activated. Combined with the stress diffusion and drainage performance of the perforated geocell, subsequent construction parameters are adjusted or reinforcement measures are taken.
[0006] Preferably, the diameter of the circular hole in the geocell in step S1 is 10 mm, and the opening ratio is 26.51%.
[0007] Preferably, the circular holes are arranged in a "plum blossom" pattern.
[0008] Preferably, in step S3, the impedance and voltage data of the self-sensing piezoelectric geocable SPGC can be remotely and automatically transmitted wirelessly to the background and an early warning information can be issued. The perforated geocells significantly enhance the integrity and bearing capacity of the roadbed at the cut-fill junction through the net effect, friction and lateral restraint effect, and reduce uneven settlement.
[0009] Preferably, the self-sensing piezoelectric geocable SPGC can monitor the internal deformation and stress state of the roadbed in real time, and promptly detect potential settlement problems through changes in impedance and voltage signals, thereby achieving intelligent early warning.
[0010] Preferably, the continuous manufacturing steps for the self-sensing piezoelectric geocable SPGC are as follows; S11. A 30µm thick PVDF is prepared using a film-forming constant temperature annealing equipment, with an annealing temperature of 120℃ and an annealing time of 60min. Then, the PVDF is stretched to about 4 times its original length using a temperature-controlled thin film stretching equipment, with a stretching temperature of 90℃ and a stretching rate of 20mm / min. Radial polarization is then performed using a high-voltage polarization device, with a polarization temperature of 90℃ and a field strength of 60kv / mm. The PVDF is then recycled into a roll by an automatic winding machine. S12. PVDF and the positive conductive core are wound and extruded into a coaxial line, and copper braid is added as the negative electrode to make it self-shielded, ensuring that it can be used in high electromagnetic interference environments. Then, the negative electrode is encapsulated in an insulating polyethylene (PE) sheath to prevent chemical corrosion and mechanical damage. The key technologies for preparing self-sensing piezoelectric geocable SPGC are the selection of PVDF formulation, stretching process and polarization conditions. The impedance of the self-sensing piezoelectric geocable SPGC decreases with the increase of frequency. When the frequency is 1kHz, the impedance drops to the kΩ level.
[0011] Preferably, the perforated geocells are provided in three groups, and each group of perforated geocells is provided with a self-sensing piezoelectric geocable (SPGC), a data acquisition box and a remote automated wireless transmission station. The self-sensing piezoelectric geocable (SPGC) includes a PE sheath, a negative copper mesh, PVDF and a positive conductive core.
[0012] The present invention has the following advantages: 1. The present invention relates to the effect of the opening ratio on the tensile properties of geocell strips, and provides results on the ultimate tensile strength and elongation of geocell strip samples with 8mm and 10mm opening ratios. Figure 11 , Figure 12 ,like Figure 11 As shown, under a certain arrangement, the tensile strength of the specimens after stretching exhibits the following characteristics: within a certain range, as the porosity increases, the tensile strength of the specimens decreases until it plateaus. Furthermore, under the same porosity, the extreme values of the ultimate tensile strength of the 8mm and 10mm specimens differ by 6.05%. This indicates that, under the same porosity, the 8mm and 10mm pore diameters have little effect on the tensile strength of the specimens. Figure 12 It can be seen that the opening ratio affects the tensile strength of the sample. Within a certain range, the tensile strength of the sample increases with the increase of the opening ratio. Comparing samples with 8 mm and 10 mm apertures, the extreme values of the tensile strength of the 8 mm and 10 mm samples differ by 11.35%. The results show that the aperture has a significant impact on the tensile strength, and the aperture changes the fracture characteristics of the sample.
[0013] 2. The tensile strength of the three hole types of the present invention is shown. Figure 13 ,analyze Figure 13 It can be seen that, within a certain range, the tensile strength of the three types of hole specimens shows that, with the increase of the opening ratio, the tensile strength decreases. The square opening is more sensitive to stress than the elliptical opening, which is more sensitive than the round opening. That is, the tensile strength of the round opening specimen is greater than that of the elliptical opening specimen, which is greater than that of the square opening specimen. This shows that the opening ratio has a significant impact on all three specimens, and also shows that the hole type is sensitive to the tensile strength of the strip.
[0014] 3. In the embodiments of the present invention, the circular holes have a low stress concentration factor and optimal mechanical properties. Their tensile strength is approximately 18.51% higher than that of square holes and approximately 6.05% higher than that of elliptical holes. The tensile strength of an 8mm hole diameter is slightly higher than that of a 10mm hole diameter (by approximately 6.05%), but its drainage capacity is weaker. The 10mm hole diameter significantly improves drainage efficiency while maintaining mechanical properties; the opening ratio is 26.51%, which is within an acceptable range of tensile strength reduction (still ≥70% of the strength of non-porous cells), while providing optimal drainage performance, making it suitable for excavation-fill junctions prone to water accumulation.
[0015] 4. When the SPGC of this invention is subjected to an external force, it undergoes minute mechanical deformation, and positive and negative charges accumulate on its inner and outer surfaces, respectively. When the external force is removed, the positive and negative charges on the upper and lower surfaces dissipate. This phenomenon of converting mechanical energy into electrical energy is called the "direct piezoelectric effect." Conversely, when the SPGC is subjected to an electric field, it undergoes minute electro-induced deformation. When the electric field is removed, the electro-induced deformation also disappears. This phenomenon of converting electrical energy into mechanical energy is called the "inverse piezoelectric effect."
[0016] Internally, the SPG is equivalent to a resistor and capacitor in parallel, meaning its impedance is the sum of resistance and reactance. When the SPG is subjected to external force, a 1kHz harmonic voltage excitation is applied. By monitoring the weak current in the circuit, the impedance of the SPG itself is calculated and compared with the impedance under the initial state, thereby quantifying the average strain information of the SPG and reflecting the changes in the soil state.
[0017] The monitoring principle of SPGC is that when uneven settlement occurs at the excavation interface, soil at different depths on the settlement surface will undergo shear failure. This causes the SPGC in the monitoring section to be subjected to oblique and horizontal shear forces, thereby monitoring changes in voltage and impedance signals. Finally, the signals are transmitted remotely and automatically to the backend and an early warning message is issued. Attached Figure Description
[0018] Figure 1 This is the sample parameter table for the present invention; Figure 2 This is the test condition table for the present invention; Figure 3 This is a tensile curve diagram of a geocell with an 8 mm aperture in this invention; Figure 4 This is a diagram showing the test results of an 8 mm aperture sample in this invention; Figure 5 This is the tensile curve of the 10 mm hole sample in this invention; Figure 6 This is a diagram showing the tensile results of a 10 mm hole specimen in this invention; Figure 7 The tensile curve of the geocell sample with square holes in this invention; Figure 8 This is a tensile test result diagram of the square hole specimen of the present invention; Figure 9 This is the tensile curve of the geocell with elliptical holes in this invention; Figure 10 This is a diagram showing the tensile results of the elliptical hole sample in this invention; Figure 11 This is a diagram showing the ultimate tensile strength of different apertures in this invention; Figure 12 This is a diagram showing the ultimate tensile strength of different apertures in this invention; Figure 13 These are tensile strength diagrams for the three types of specimens used in this invention; Figure 14 The tensile strength diagrams for the three types of samples in this invention are shown. Figure 15 This is a three-dimensional schematic diagram of the perforated geocell in this invention; Figure 16 This is a schematic diagram of the structural parameters of the perforated geocell in this invention; Figure 17 This is a schematic diagram illustrating the deployment and monitoring principle of the perforated geocell and self-sensing piezoelectric geocable SPGC in this invention. Figure 18 This is a three-dimensional schematic diagram of the self-sensing piezoelectric geocable SPGC of the present invention.
[0019] In the diagram, 1. Perforated geocell; 2. Self-sensing piezoelectric geocable (SPGC); 3. Data acquisition box; 4. Remote automated wireless transmission station; 5. Positive conductive core; 6. PVDF; 7. Negative copper mesh; 8. PE sheath. Detailed Implementation
[0020] The present invention will be further described below with reference to the accompanying drawings. The scope of protection of the present invention is not limited to the following description: like Figures 1-18 As shown, an improved intelligent control method for subgrade settlement at the cut-fill interface is presented. To determine the optimal pore type, pore size, and open area ratio of geocells, uniaxial tensile testing was conducted. The tensile testing equipment used was a Sansi Zongheng microcomputer-controlled UTM4000 electronic universal testing machine, which is existing technology. The raw material for the geocell strip samples was HDPE. Figure 1 As shown; Four working conditions were designed based on different hole types and diameters, including three hole diameters: round, square, and elliptical. Since a 10mm hole diameter, a "cloverleaf" pattern, and a 20mm hole spacing are commonly used in engineering practice, the hole spacing and drilling method for each sample were kept consistent with engineering applications. Two hole diameters were set: 8mm and 10mm, with the number of rows ranging from one to six, numbered sequentially as follows: Figure 2 As shown; In this embodiment, to study the effect of aperture on the tensile properties of the strip, six samples of geocell strips with circular holes of 8 mm aperture were subjected to tensile testing. The tensile results are as follows: Figure 3 , Figure 4 As shown. Tensile tests were performed on six samples of geocell strips with circular holes of 10 mm diameter. The tensile results are as follows. Figure 5 , Figure 6 As shown in the figure. The results indicate that, when the aperture ratio is the same, comparing the tensile strength data of 8mm and 10mm circular hole specimens, the tensile strength of the former is slightly greater than that of the latter, with a difference of 6.05% in their extreme values, which is negligible in engineering. This suggests that, within a certain range, the aperture diameter of the circular hole specimen has little effect on its tensile strength. However, when the aperture ratio is the same, comparing the tensile rates shows that the aperture diameter has a significant impact on the tensile rate of the specimen, altering its ductile-brittle fracture characteristics.
[0021] In this embodiment, to study the effect of hole shape on the tensile properties of the strip, six samples of geocell strips with square holes were subjected to tensile testing. The tensile results are as follows: Figure 7 , Figure 8 As shown. Tensile tests were performed on six specimens of geocell strips with elliptical holes, and the tensile results are as follows. Figure 9 , Figure 10 As shown in the figure. The results indicate that all three types of geocell strip specimens exhibit a significant plastic strengthening stage under tension. The square opening is more sensitive to stress than the elliptical opening, which is in turn more sensitive than the round opening. Specifically, the tensile strength of the round opening specimen is greater than that of the elliptical opening specimen, which is greater than that of the square opening specimen. This suggests that under the same opening ratio, the opening shape significantly affects the tensile strength of the geocell strips. At the same opening ratio, within a certain range, the change in tensile strength due to the opening shape is not significant.
[0022] In this embodiment, to study the effect of porosity on the tensile properties of the geocell strips, the ultimate tensile strength and elongation were measured for geocell strip specimens with 8mm and 10mm porosity. Figure 11 , Figure 12 ,like Figure 11As shown, under a certain arrangement, the tensile strength of the specimens after stretching exhibits the following characteristics: within a certain range, as the open area ratio increases, the tensile strength of the specimens decreases until it stabilizes. Furthermore, under the same open area ratio, the extreme values of the ultimate tensile strength of the 8mm and 10mm specimens differ by 6.05%. This indicates that, under the same open area ratio, the 8mm and 10mm pore diameters have little effect on the tensile strength of the specimens. Figure 11 It can be seen that the opening ratio affects the tensile strength of the sample. Within a certain range, the tensile strength of the sample increases with the increase of the opening ratio. Comparing samples with 8 mm and 10 mm apertures, the extreme values of the tensile strength of the 8 mm and 10 mm samples differ by 11.35%. The results show that the aperture has a significant impact on the tensile strength, and the aperture changes the fracture characteristics of the sample.
[0023] In this embodiment, the tensile strength of the three hole types is used as a basis for determination. Figure 13 ,analyze Figure 13 It can be seen that, within a certain range, the tensile strength of the three types of hole specimens shows that, with the increase of the opening ratio, the tensile strength decreases. The square opening is more sensitive to stress than the elliptical opening, which is more sensitive than the round opening. That is, the tensile strength of the round opening specimen is greater than that of the elliptical opening specimen, which is greater than that of the square opening specimen. This shows that the opening ratio has a significant impact on all three specimens, and also shows that the hole type is sensitive to the tensile strength of the strip.
[0024] In this embodiment, the elongation rate of the three hole types is used to make... Figure 14 ,Depend on Figure 14 It can be seen that within a certain range, as the opening ratio increases, the elongation of the three hole types of the specimens does not change significantly, indicating that the hole type has little effect on the elongation of the specimens. If this range is exceeded, the opening ratio increases sharply, and the elongation of the specimen with a round hole is greater than that of the specimen with an elliptical hole, which is greater than that of the specimen with a square hole. This also proves that the hole type has an effect on the elongation of the specimens.
[0025] In this embodiment, the above research results show that circular holes have a low stress concentration factor and optimal mechanical properties. Their tensile strength is approximately 18.51% higher than that of square holes and approximately 6.05% higher than that of elliptical holes. The tensile strength of an 8mm hole diameter is slightly higher than that of a 10mm hole diameter (by approximately 6.05%), but its drainage capacity is weaker. A 10mm hole diameter significantly improves drainage efficiency while maintaining mechanical properties; its open area ratio of 26.51% is within an acceptable range of tensile strength reduction (still ≥70% of the strength of non-porous cells), while providing optimal drainage performance, making it suitable for excavation-fill junctions prone to water accumulation.
[0026] In this embodiment, the manufacturing of the self-sensing piezoelectric geocable SPGC2 is a continuous process. The first step involves preparing a 30µm thick PVDF6 using a film-forming isothermal annealing device (annealing temperature and time: 120℃, 60min). Then, the PVDF6 is stretched to approximately four times its original length using a temperature-controlled film stretching device (stretching temperature and rate: 90℃, 20mm / min), and radially polarized using a high-voltage polarization device (polarization temperature and field strength: 90℃, 60kv / mm). Finally, it is wound into a coil using an automatic winding machine. The second step uses traditional cable manufacturing processes, where the PVDF6 and the positive conductive core 5 are wound and extruded into a coaxial line, and copper braid is added as the negative electrode (making it self-shielded, i.e., the negative electrode copper mesh 7, allowing use in high electromagnetic interference environments). Then, the negative electrode is encapsulated in an insulating polyethylene (PE) sheath 8 to prevent chemical corrosion and mechanical damage. The key technologies for manufacturing the self-sensing piezoelectric geocable SPGC2 are the selection of the PVDF formulation, the stretching process, and the polarization conditions. The impedance of the self-sensing piezoelectric geocable SPGC2 decreases with increasing frequency. At a frequency of 1kHz, the impedance drops to the kΩ level.
[0027] In this embodiment, when the self-sensing piezoelectric geocable SPGC2 is subjected to an external force, it undergoes slight mechanical deformation, resulting in the accumulation of positive and negative charges on its inner and outer surfaces, respectively. When the external force is removed, the positive and negative charges on the upper and lower surfaces dissipate. This phenomenon of converting mechanical energy into electrical energy is called the "direct piezoelectric effect." Conversely, when the self-sensing piezoelectric geocable SPGC2 is subjected to an electric field, it undergoes slight electroinduced deformation. When the electric field is removed, the electroinduced deformation also disappears. This phenomenon of converting electrical energy into mechanical energy is called the "inverse piezoelectric effect."
[0028] In this embodiment, the self-sensing piezoelectric geocable SPGC2 is internally equivalent to a combination of a resistor and a capacitor in parallel, i.e., the impedance is the sum of resistance and reactance. When the self-sensing piezoelectric geocable SPGC2 is subjected to an external force, a 1kHz harmonic voltage excitation is applied to it. The impedance of the self-sensing piezoelectric geocable SPGC2 itself is calculated by monitoring the weak current in the circuit and compared with the impedance in the initial state, thereby quantifying the average strain information of the self-sensing piezoelectric geocable SPGC2 and reflecting the change in soil state.
[0029] In this embodiment, the monitoring principle of the self-sensing piezoelectric geocable SPGC2 is that when uneven settlement occurs at the excavation interface, the soil at different depths on the settlement surface will undergo shear failure, which will cause the self-sensing piezoelectric geocable SPGC in the measuring section to be subjected to oblique and horizontal shear action, thereby monitoring the changes in voltage and impedance signals, and finally transmitting them to the background remotely and automatically and wirelessly to issue early warning information.
[0030] In this embodiment, there are three sets of perforated geocells. Each set of perforated geocells 1 is equipped with a self-sensing piezoelectric geocable cable SPGC2, a data acquisition box 3, and a remote automated wireless transmission station 4. The self-sensing piezoelectric geocable cable SPGC2 includes a PE sheath 8, a negative copper mesh 7, a PVDF 6, and a positive conductive core 5.
[0031] The technical solution of the present invention includes the following steps: Selection and Optimization of Perforated Geocells: Geocells made of high-density polyethylene (HDPE) are selected, with a cell height of 100mm, a thickness of 1.0mm, and a weld spacing of 330mm. Circular holes with a diameter of 10mm are made in the cell strips, resulting in a perforation rate of 26.51%, arranged in a "quincunx" pattern with a hole spacing of 20mm. This parameter combination ensures reinforcement while significantly improving lateral drainage capacity. Based on the subgrade fill height and load conditions, multiple layers of perforated geocells are laid in the compression zone at the cut-fill interface.
[0032] Self-sensing piezoelectric geocable (SPGC) deployment: Self-sensing piezoelectric geocables (SPGC) with a diameter of 2.7 mm are deployed in layers along the longitudinal direction of the roadbed at the cut-fill junction. The positive and negative terminals of the SPGC are connected to a data acquisition box to monitor impedance and voltage signal changes in real time. A bilinear model can be used to establish a shear displacement-normalized impedance relationship to quantify soil strain information.
[0033] Intelligent monitoring and feedback control: Impedance and voltage signals of the self-sensing piezoelectric geocell (SPGC) are transmitted in real-time to a backend computer via a remote automated wireless transmission station. The normalized impedance inflection point and RMS voltage changes are analyzed. An early warning mechanism is activated when a significant decrease in normalized impedance or an abnormal voltage signal is detected. Based on the stress diffusion and drainage performance of the perforated geocells, subsequent construction parameters are adjusted or reinforcement measures are implemented.
[0034] The diameter of the circular holes in the perforated geocell is 10 mm, and the perforation rate is 26.51%.
[0035] The circular holes are arranged in a "plum blossom" pattern.
[0036] When the self-sensing piezoelectric geocable SPGC is subjected to external force, it will undergo slight mechanical deformation and generate positive and negative charge accumulation on its inner and outer surfaces, respectively.
[0037] The copper braid serves as the negative electrode, providing self-shielding and allowing it to be used in environments with high electromagnetic interference.
[0038] The impedance and voltage data of the self-sensing piezoelectric geocable SPGC can be remotely and automatically transmitted wirelessly to the backend and warning information can be issued.
[0039] Perforated geocells significantly enhance the integrity and bearing capacity of the subgrade at the cut-fill junction through the netting effect, friction, and lateral restraint effect, and reduce uneven settlement.
[0040] The aperture parameters (round holes, plum blossom-shaped distribution, 10mm aperture, 26.51% aperture ratio) effectively promote drainage inside the subgrade and accelerate the soil consolidation process while ensuring mechanical properties.
[0041] The SPGC2 self-sensing piezoelectric geocable can monitor the internal deformation and stress state of the roadbed in real time, and detect potential settlement problems in a timely manner through changes in impedance and voltage signals, thus achieving intelligent early warning.
[0042] The SPGC2 monitoring system for self-sensing piezoelectric geocables is far less expensive than traditional distributed monitoring equipment. The perforated geocells are easy to construct, and the overall solution has a high cost-performance ratio. Meanwhile, the data acquisition box, remote automated wireless transmission station, high-voltage polarization device, and temperature-controlled thin film stretching equipment are all existing technologies, which will not be elaborated here.
[0043] Finally, it should be noted that the above descriptions are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.
Claims
1. An improved intelligent control method for roadbed settlement at the cut-fill junction, characterized in that: Includes the following steps; S1. Selection and optimization of perforated geocells: Geocells made of high-density polyethylene (HDPE) material are selected. The geocell height is 100mm, the thickness is 1.0mm, the welding distance is 330mm, and circular holes with a diameter of 10mm are opened on the geocell strips. The perforation rate is 26.51%, and the holes are arranged in a "plum blossom" pattern with a hole spacing of 20mm. S2. Based on the embankment height and load conditions, lay multiple layers of perforated geocells in the compression zone at the cut-fill junction. S3. Deployment of self-sensing piezoelectric geocable SPGC: Self-sensing piezoelectric geocable SPGC with a diameter of 2.7mm is deployed in layers along the longitudinal direction of the roadbed at the cut-fill junction. The positive and negative terminals of the self-sensing piezoelectric geocable SPGC are connected to the data acquisition box respectively to monitor the changes in impedance and voltage signals in real time. The shear displacement-normalized impedance relationship can be established through a bilinear model to quantify the soil strain information. S4. Intelligent monitoring and feedback control: The impedance and voltage signals of the self-sensing piezoelectric geocell (SPGC) are transmitted to the background computer in real time through a remote automated wireless transmission station to analyze the normalized impedance inflection point value and effective voltage change. When a significant drop in normalized impedance or abnormal voltage signal is detected, an early warning mechanism is activated. Combined with the stress diffusion and drainage performance of the perforated geocell, subsequent construction parameters are adjusted or reinforcement measures are taken.
2. The improved intelligent control method for roadbed settlement at the cut-fill junction according to claim 1, characterized in that: In step S1, the diameter of the circular holes in the geocells is 10 mm, and the opening rate is 26.51%.
3. The improved intelligent control method for roadbed settlement at the cut-fill junction according to claim 1, characterized in that: The circular holes are arranged in a "plum blossom" pattern.
4. The improved intelligent control method for roadbed settlement at the cut-fill junction according to claim 1, characterized in that: In step S3, the impedance and voltage data of the self-sensing piezoelectric geocable SPGC can be remotely and automatically transmitted wirelessly to the background and an early warning information can be issued. The perforated geocells significantly enhance the integrity and bearing capacity of the roadbed at the cut-fill junction through the net effect, friction and lateral restraint effect, and reduce uneven settlement.
5. An improved intelligent control method for roadbed settlement at the cut-fill junction according to claim 1, characterized in that: The self-sensing piezoelectric geocable SPGC can monitor the internal deformation and stress state of the subgrade in real time, and promptly detect potential settlement problems through changes in impedance and voltage signals, thus achieving intelligent early warning.
6. An improved intelligent control method for roadbed settlement at the cut-fill junction according to claim 1, characterized in that: The continuous manufacturing steps of the self-transforming piezoelectric geocable SPGC are as follows; S11. A 30µm thick PVDF is prepared using a film-forming constant temperature annealing equipment, with an annealing temperature of 120℃ and an annealing time of 60min. Then, the PVDF is stretched to about 4 times its original length using a temperature-controlled thin film stretching equipment, with a stretching temperature of 90℃ and a stretching rate of 20mm / min. Radial polarization is then performed using a high-voltage polarization device, with a polarization temperature of 90℃ and a field strength of 60kv / mm. The PVDF is then recycled into a roll by an automatic winding machine. S12. PVDF and the positive conductive core are wound and extruded into a coaxial line, and copper braid is added as the negative electrode to make it self-shielded, ensuring that it can be used in high electromagnetic interference environments. Then, the negative electrode is encapsulated in an insulating polyethylene (PE) sheath to prevent chemical corrosion and mechanical damage. The key technologies for preparing self-sensing piezoelectric geocable SPGC are the selection of PVDF formulation, stretching process and polarization conditions. The impedance of the self-sensing piezoelectric geocable SPGC decreases with the increase of frequency. When the frequency is 1kHz, the impedance drops to the kΩ level.
7. An improved intelligent control method for roadbed settlement at the cut-fill junction according to claim 1, characterized in that: The perforated geocell is provided in three groups. Each group of perforated geocells is equipped with a self-sensing piezoelectric geocable (SPGC), a data acquisition box, and a remote automated wireless transmission station. The self-sensing piezoelectric geocable (SPGC) includes a PE sheath, a negative copper mesh, PVDF, and a positive conductive core.