A 3D-printed concrete retaining wall based on an automatic feedback mechanism and its construction method

Abstract

This invention provides a 3D-printed concrete retaining wall based on an automatic feedback mechanism, comprising: a layered printing structure formed by stacking multiple layers of concrete material, each layer being 8-15 mm thick; a retaining wall base, wherein the retaining wall base is a C30 concrete base; an optimized irregular path, a printing trajectory generated based on finite element stress analysis to maximize the stress concentration factor inside the retaining wall; a composite material protective layer, disposed on the surface of the layered printing structure, the composite material protective layer containing uniformly distributed fiber reinforcement material, the fiber composite material being added to the 3D-printed concrete at a ratio of 0.5%-1%; drainage pipes, disposed in the layered printing structure and the composite material protective layer; and an embedded sensor network, distributed in key stress areas within the retaining wall, to monitor stress, temperature, and humidity data in real time. This invention dynamically adjusts the printing path based on feedback during the printing process, reducing the cracking rate, minimizing material waste, and improving construction efficiency by reducing manual intervention through automated control.

Description

Technical Field

[0001] This invention relates to the field of intelligent construction technology for road retaining walls, and in particular to a 3D-printed concrete retaining wall based on an automatic feedback mechanism and its construction method. Background Technology

[0002] Traditional retaining wall construction methods typically employ cast-in-place concrete or precast components, which suffer from long construction cycles, significant material waste, and high labor costs. In recent years, the application of 3D printing technology in the construction field has gradually increased, but its application in retaining wall construction still faces many challenges:

[0003] 1. Comparative document CN116777898B proposes a method for measuring cracks during the construction of 3D printed retaining walls based on AFFormer. Its protected permissions include: "The following steps are included: training an AFFormer neural network using a dataset with labeled information to obtain the binarized image segmentation result of the crack; setting a connectivity threshold, deleting connected components with fewer pixels than the connectivity threshold through connected component denoising to obtain a denoised crack skeleton image; refining the cracks using morphological processing on the denoised crack skeleton image to obtain the refined cracks; simultaneously employing the Canny edge detection algorithm to calculate the grayscale gradient of the crack binary image on the denoised crack skeleton image, finding image edges and obtaining crack edge maps; performing a pixel-by-pixel logical AND operation between the edge maps obtained by Canny edge detection and the refined cracks; calculating the crack pixel width using an eight-direction search method to obtain the actual crack width. This significantly improves the accuracy of segmentation and prediction, enabling real-time high-precision measurement." However, it relies on post-processing of images and cannot adjust printing parameters in real time.

[0004] 2. Reference document CN114856694B proposes a filling retaining wall and construction method based on an integrated flexible frame. Its protected scope is as follows: "After ore extraction, the construction method determines the location of the filling retaining wall at the junction of the stope and the stope connecting road, obtains the stope contour data, and reconstructs the digital stope contour surface. Based on the reconstructed digital stope contour surface, an integrated flexible frame for the filling retaining wall is designed, including a mesh wall structure, a bottom fixing structure, and a support structure. The cross-section of the mesh wall structure is a right-angled trapezoid, and one side of the filling retaining wall within the filling body is a right-angled trapezoidal inclined wall. The integrated flexible frame is 3D printed, packaged, and transported to the site. After unfolding, it is fixed to the stope floor. Waste rock is then loaded into the mesh wall structure, and filter cloth is laid and fixed on the outer surface of the inclined wall to obtain the filling retaining wall. This invention is simple and rapid to construct, reduces worker labor intensity, and effectively utilizes on-site waste rock, improving the construction efficiency of the filling retaining wall." However, it does not address the stress concentration problem of irregularly shaped retaining walls.

[0005] Therefore, a 3D-printed concrete retaining wall based on an automatic feedback mechanism and its construction method are proposed to solve the above problems. Summary of the Invention

[0006] This invention addresses the aforementioned problems by proposing a 3D-printed concrete retaining wall based on an automatic feedback mechanism, comprising:

[0007] The layered printing structure is formed by stacking multiple layers of concrete material one after another, with each layer being 8-15mm thick;

[0008] Retaining wall base, wherein the retaining wall base is a C30 concrete base;

[0009] The irregular optimization path, based on the printing trajectory generated by finite element stress analysis, maximizes the stress concentration factor inside the retaining wall. ;

[0010] A composite material protective layer is applied to the surface of the layered printed structure. The composite material protective layer contains uniformly distributed fiber reinforcement material, and the proportion of fiber composite material added to the 3D printed concrete is 0.5% - 1%.

[0011] Drainage pipes are installed within the layered printed structure and composite material protective layer;

[0012] An embedded sensor network is distributed in key stress areas within the retaining wall to monitor stress, temperature, and humidity data in real time.

[0013] Preferably, the fiber composite material is at least one of carbon fiber, glass fiber, and basalt fiber, and the fiber composite material is added to the 3D printed concrete at a ratio of 0.5% to 1%, with a length of 10-30 mm and a diameter of 0.1-0.5 mm.

[0014] Preferably, the irregular optimization path is generated using the following formula:

[0015] ;

[0016] in, For local maximum stress, This is the nominal stress.

[0017] Preferably, the sensor network includes a fiber optic grating sensor, a temperature sensor, and a humidity sensor, with a data sampling frequency ≥10Hz.

[0018] In addition, the present invention also discloses a construction method for a 3D-printed concrete retaining wall based on an automatic feedback mechanism, characterized by comprising the following steps:

[0019] Step S1: Generate the initial printing path based on the retaining wall design parameters, and embed the finite element model to calculate the initial stress distribution;

[0020] Step S2: Start the 3D printer to print the first layer, and simultaneously collect real-time stress data. ;

[0021] Step S3: Optimize subsequent printing parameters through a dynamic adjustment algorithm. The extrusion rate Q is adjusted according to the following formula:

[0022] ;

[0023] in, The initial extrusion rate, This is the material rheological coefficient, with a value ranging from 0.2 to 0.5. and These are the maximum stress and average stress of the current layer, respectively.

[0024] Step S4: Repeat steps S2-S3 until printing is complete, and perform post-processing and maintenance.

[0025] Furthermore, the finite element model described in step S1 uses a non-uniform mesh, with the mesh size decreasing gradually with the height of the retaining wall.

[0026] Furthermore, in step S3 if If this occurs, an alarm is triggered and printing is paused. Epoxy resin is then injected to provide localized reinforcement. For design stress.

[0027] Furthermore, post-treatment maintenance includes covering with a protective film and spraying with a nano-silicate penetrating crystallizer, with a maintenance time of ≥7 days.

[0028] Furthermore, in step S2, a lidar is used to scan the morphology of the printed layer in real time, and path replanning is triggered when the morphology deviation is greater than 3mm.

[0029] Furthermore, the rheological coefficient of the material Dynamically corrected based on ambient humidity H:

[0030] ;

[0031] in, The baseline value is set to 0.3, and H represents the ambient humidity.

[0032] The present invention has the following beneficial effects:

[0033] 1. This invention introduces a dynamic stress feedback mechanism: embedded sensors monitor stress in real time, and combined with algorithms, the extrusion rate is adjusted to prevent cracks, greatly reducing the crack occurrence rate during construction, saving materials, reducing cost waste, and the embedded sensors can continue to be connected to the post-construction monitoring system for continuous maintenance monitoring after construction is completed.

[0034] 2. This invention optimizes the construction of irregular paths: a printing path with a low stress concentration factor is generated based on finite element analysis, which is suitable for complex route construction. The automated closed-loop control reduces manual intervention and greatly improves construction efficiency.

[0035] 3. This invention introduces adaptive control based on the construction environment: it introduces a humidity correction coefficient to optimize material rheological behavior, improve the stability of printing quality, and is suitable for complex geological and high humidity environments. Attached Figure Description

[0036] Figure 1 This is a schematic diagram of the retaining wall structure in this invention;

[0037] Figure 2 This is a flowchart of the dynamic stress feedback mechanism in this invention;

[0038] Figure 3 This is a flowchart of the irregular path optimization process in this invention. Detailed Implementation

[0039] The present invention will be further described below with reference to the accompanying drawings and embodiments:

[0040] See Figures 1 to 3 A 3D-printed concrete retaining wall based on an automatic feedback mechanism includes:

[0041] Layered printing structure 1 is formed by stacking multiple layers of concrete material layer by layer, with each layer being 8-15mm thick;

[0042] Retaining wall base 2, wherein the retaining wall base is a C30 concrete base;

[0043] The irregular optimization path, based on the printing trajectory generated by finite element stress analysis, maximizes the stress concentration factor inside the retaining wall. ;

[0044] Composite material protective layer 3 is applied to the surface of the layered printed structure. The composite material protective layer contains uniformly distributed fiber composite material, and the addition ratio of fiber composite material in 3D printed concrete is 0.5% - 1%.

[0045] Drainage pipe 4 is installed in the layered printed structure 1 and the composite material protective layer 3. The number and location of drainage pipes are set according to the actual engineering environment.

[0046] An embedded sensor network, distributed across key stress-bearing areas within the retaining wall, monitors stress, temperature, and humidity data in real time. Fiber Bragg grating sensors and temperature and humidity sensors can be deployed at the bottom, middle, and top of the retaining wall, respectively; data is sampled at a frequency of 10Hz and transmitted to the control center in real time; this improves real-time monitoring accuracy and reduces construction failure rates.

[0047] Preferably, the fiber composite material is at least one of carbon fiber, glass fiber, and basalt fiber, and the fiber composite material is added to the 3D printed concrete at a ratio of 0.5% to 1%, with a length of 10-30 mm and a diameter of 0.1-0.5 mm.

[0048] Preferably, the irregular optimization path is generated using the following formula:

[0049] ;

[0050] in, For local maximum stress, The nominal stress is used. When the retaining wall is curved or stepped, the pouring path of its key stress areas is optimized. The thickness of the printed layer and the extrusion rate of the nozzle are dynamically adjusted according to the design dimensions to ensure the strength of the irregular structure and the overall coordination and consistency of the retaining wall construction.

[0051] Preferably, the sensor network includes fiber Bragg grating sensors, temperature sensors, and humidity sensors, with a data sampling frequency ≥10Hz. During construction, the number and types of sensors in the sensor network are arranged according to the key stress areas in the design. Embedded sensors monitor stress in real time, and combined with algorithms, the extrusion rate is adjusted in a timely manner to prevent cracks, greatly reducing the crack incidence rate during construction, saving materials, and reducing waste in construction costs. Moreover, after construction is completed, the embedded sensors can continue to be connected to the post-construction monitoring system for ongoing maintenance and monitoring.

[0052] In addition, the present invention also discloses a construction method for a 3D-printed concrete retaining wall based on an automatic feedback mechanism, characterized by comprising the following steps:

[0053] Step S1: Generate the initial printing path based on the retaining wall design parameters, and embed the finite element model to calculate the initial stress distribution;

[0054] Step S2: Start the 3D printer to print the first layer, and simultaneously collect real-time stress data. ;

[0055] Step S3: Optimize subsequent printing parameters through a dynamic adjustment algorithm. The extrusion rate Q is adjusted according to the following formula:

[0056] ;

[0057] in, The initial extrusion rate, This is the material rheological coefficient, with a value ranging from 0.2 to 0.5. and These are the maximum stress and average stress of the current layer, respectively.

[0058] Step S4: Repeat steps S2-S3 until printing is complete, and perform post-processing and maintenance.

[0059] Furthermore, the finite element model described in step S1 uses a non-uniform mesh, with the mesh size decreasing gradually with the height of the retaining wall.

[0060] Furthermore, in step S3 if If this occurs, an alarm is triggered and printing is paused. Epoxy resin is then injected to provide localized reinforcement. This design incorporates stress reduction. It lowers the cracking rate, reduces rework frequency, significantly saves material usage, and improves construction efficiency.

[0061] Furthermore, post-treatment curing includes covering with a curing film and spraying with a nano-silicate penetrating crystallizer, with a curing time of ≥7 days. The curing film should be covered within 1-6 hours after printing to prevent moisture evaporation; after 3 days of curing, the nano-silicate penetrating crystallizer should be sprayed to enhance surface density; the total curing time should be ≥7 days to ensure the concrete strength meets design requirements.

[0062] Furthermore, in step S2, a lidar is used to scan the morphology of the printed layer in real time, and path replanning is triggered when the morphology deviation is greater than 3mm.

[0063] Furthermore, the rheological coefficient of the material Dynamically corrected based on ambient humidity H:

[0064] ;

[0065] in, The baseline value is 0.3, and H represents the ambient humidity. When the ambient temperature is below 10℃, increase the amount of concrete admixture to ensure material fluidity.

[0066] The specific embodiments described above are merely preferred technical solutions of the present invention and should not be considered as limitations on the present invention. The scope of protection of the present invention should be limited to the technical solutions described in the claims, including equivalent substitutions of the technical features described in the claims. That is, equivalent substitutions and improvements within this scope are also within the scope of protection of the present invention.

Claims

1. A construction method for a 3D-printed concrete retaining wall based on an automatic feedback mechanism, characterized in that, 3D-printed concrete retaining walls based on automatic feedback mechanisms include: The layered printing structure is formed by stacking multiple layers of concrete material one after another, with each layer being 8-15mm thick; Retaining wall base, wherein the retaining wall base is a C30 concrete base; The irregular optimization path, based on the printing trajectory generated by finite element stress analysis, maximizes the stress concentration factor inside the retaining wall. ; Its irregular optimization path is generated by the following formula: in, For local maximum stress, For nominal stress, A composite material protective layer is applied to the surface of the layered printed structure. The protective layer contains uniformly distributed fiber composite materials, and the fiber composite materials are added to the 3D printed concrete at a ratio of 0.5% to 1%. Drainage pipes are installed within the layered printed structure and composite material protective layer; An embedded sensor network, distributed within key stress-bearing areas of the retaining wall, monitors stress, temperature, and humidity data in real time. The construction method includes the following steps: Step S1: Generate the initial printing path based on the retaining wall design parameters, and embed the finite element model to calculate the initial stress distribution; Step S2: Start the 3D printer to print the first layer, and simultaneously collect real-time stress data. ; Step S3: Optimize subsequent printing parameters through a dynamic adjustment algorithm. The extrusion rate Q is adjusted according to the following formula: ； in, The initial extrusion rate, This is the material rheological coefficient, with a value ranging from 0.2 to 0.

5. and These are the maximum stress and average stress of the current layer, respectively. Step S4: Repeat steps S2-S3 until printing is complete, and perform post-processing and maintenance.

2. The construction method for a 3D-printed concrete retaining wall based on an automatic feedback mechanism according to claim 1, characterized in that, The fiber composite material is at least one of carbon fiber, glass fiber, and basalt fiber, and the length of the fiber composite material in the 3D printed concrete is 10-30 mm and the diameter is 0.1-0.5 mm.

3. The construction method for a 3D-printed concrete retaining wall based on an automatic feedback mechanism according to claim 1, characterized in that, The embedded sensor network includes fiber optic grating sensors, temperature sensors, and humidity sensors, with a data sampling frequency ≥10Hz.

4. The construction method for a 3D-printed concrete retaining wall based on an automatic feedback mechanism according to claim 1, characterized in that, The finite element model described in step S1 uses a non-uniform mesh.

5. The construction method for a 3D-printed concrete retaining wall based on an automatic feedback mechanism according to claim 1, characterized in that, If in step S3 If this occurs, an alarm is triggered and printing is paused. Epoxy resin is then injected to provide localized reinforcement. For design stress.

6. The construction method for a 3D-printed concrete retaining wall based on an automatic feedback mechanism according to claim 1, characterized in that, Post-treatment maintenance includes covering with a protective film and spraying with a nano-silicate penetrating crystallizer, with a maintenance time of ≥7 days.

7. The construction method for a 3D-printed concrete retaining wall based on an automatic feedback mechanism according to claim 1, characterized in that, In step S2, a lidar is used to scan the morphology of the printed layer in real time. When the morphology deviation is greater than 3mm, path replanning is triggered.

8. The construction method for a 3D-printed concrete retaining wall based on an automatic feedback mechanism according to claim 1, characterized in that, The material rheological coefficient According to ambient humidity H Dynamic correction: ； in, The baseline value is set at 0.

3. H This refers to ambient humidity.

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