A geopolymer solidified soft soil deterioration testing machine simulating tide-load coupling

Abstract

The present application relates to a kind of simulation tidal-load coupling geopolymer solidification soft soil deterioration testing machine, belong to civil engineering detection technical field, including load applying module, wave manufacturing module, loading frame, seawater circulating tank and control module, the control module is electrically connected with load applying module and wave manufacturing module respectively, the loading frame is set in seawater circulating tank and is used to load the piece to be measured, the load applying module is used to load the piece to be measured, the wave manufacturing module is used to manufacture wave in seawater circulating tank;It also includes detection module, the detection module is used to detect ion permeation;It also includes the sensing module electrically connected with control module, the sensing module is used to detect the temperature of load applying module and upload to control module;When the control module judges temperature exceeds temperature threshold value, instructs load applying cycle frequency to reduce and instructs wave manufacturing module to improve wave-making frequency.

Description

Technical Field

[0001] This invention belongs to the field of civil engineering testing technology, specifically relating to a geopolymer solidification soft soil deterioration test machine that simulates tidal-load coupling. Background Technology

[0002] Geopolymers, also known as geopolymers or geopolymers, are inorganic silica-alumina cementitious materials. They consist of a three-dimensional network structure composed of silicon-oxygen tetrahedra and aluminum-oxygen tetrahedra. Their energy consumption and CO2 emissions are only 20%-60% of those of silicate cement, and they have the potential to replace traditional cement.

[0003] Civil engineering materials require destructive or deterioration tests to determine their true load-bearing capacity. For materials near water, it is often necessary to simultaneously simulate tidal environments during load tests to mimic the actual conditions faced by the materials. For example, Chinese patent CN112709266A describes a test system and method for simulating the bearing capacity of coral reef sand under tidal conditions. The test system for simulating the bearing capacity of coral reef sand under tidal conditions includes a model box, a loading device, a deformation measurement mechanism, and a water circulation mechanism. The water circulation mechanism has a timing device, a water tank connected to the model box, and an air pump connected to the water tank. By using the air pump to regulate and control the air pressure in the water tank, the amount of water entering the model box can be changed, thereby simulating the tidal environment. The timing device also facilitates the control of the tidal cycle time by the experimenters. Furthermore, the loading device includes dynamic and static load mechanisms, which can apply dynamic or static loads to the coral reef sand, increasing the simulability of the test system and facilitating the determination of the bearing characteristics of coral reef sand under different conditions, making it highly applicable.

[0004] However, the above invention tests the bearing capacity of coral reef sand and does not consider the possible scenarios when it is applied to geopolymer-stabilized soft soil materials. For example, the dissolution reaction of geopolymers is very sensitive to temperature. If the dissolution rate is to be measured simultaneously, the testing device itself will affect the temperature, which in turn will affect the dissolution rate and ion penetration. If the influence is not excluded, the measured data will be false data. The environmental influence is not excluded, and the test accuracy is not high. Therefore, a geopolymer-stabilized soft soil deterioration test machine that simulates tidal-load coupling and has high test accuracy is needed, which takes into account the environmental influence. Summary of the Invention

[0005] To address the aforementioned problems in the existing technology, this invention provides a geopolymer solidification soft soil degradation testing machine that simulates tidal-load coupling, featuring consideration of environmental influences and high testing accuracy.

[0006] The objective of this invention can be achieved through the following technical solutions: A test machine for simulating the degradation of geopolymer-stabilized soft soil by simulating tidal-load coupling includes a load application module, a wave generation module, a loading frame, a seawater circulation tank, and a control module. The control module is electrically connected to the load application module and the wave generation module. The loading frame is set in the seawater circulation tank and is used to load the test specimen. The load application module is used to apply load to the test specimen. The wave generation module is used to generate waves in the seawater circulation tank. It also includes a detection module for detecting ion permeation; It also includes a sensing module electrically connected to the control module, the sensing module being used to detect the temperature of the load application module and upload the data to the control module; When the control module determines that the temperature exceeds the threshold, it commands the load to reduce the cycle frequency and commands the wave generation module to increase the wave generation frequency.

[0007] As a preferred embodiment of the present invention, the sensing module is used to detect the temperature W of the load application module and upload it to the control module. The control module instructs the load application cycle frequency to be adjusted to 1-A1 times the original, and instructs the wave generation frequency of the wave generation module to be adjusted to 1+A1 times the original, where A1=0.1x-0.1, x=W / W0, and W0 is a preset temperature threshold.

[0008] As a preferred embodiment of the present invention, the sensing module is used to monitor the change in the cross-sectional area of ​​the current test piece and upload the cross-sectional area to the control module. When the control module determines that the cross-sectional area is lower than a threshold, it reduces the applied pressure of the load application module.

[0009] As a preferred embodiment of the present invention, the sensing module is used to transmit the cross-sectional area J to the control module, and the control module corrects the load of the load application module to the original A2 times, where A2=J / J0×c, c is a preset constant, and J0 is a preset cross-sectional area threshold.

[0010] As a preferred embodiment of the present invention, the sensing module is used to read the acceleration and turbidity of the wave generation module and upload them to the control module. The control module calculates the comprehensive ion detection confidence level based on the acceleration and turbidity. When the control module determines that the confidence level is higher than the threshold, the control module instructs the detection module to stop detection.

[0011] As a preferred technical solution of the present invention, the control module calculates the comprehensive ion detection confidence level Z based on the acceleration a and the turbidity H, where Z = (a / a0 × d) × (H / H0 × e), and d and e are preset constants.

[0012] As a preferred embodiment of the present invention, it further includes a control panel, wherein the control panel is electrically connected to the control module, and the control panel is used to input the values ​​of W0, J0, a0, and H0.

[0013] (1) By setting the sensor module to detect the temperature, and when the temperature exceeds the threshold, the load application cycle frequency is reduced and the wave generation frequency of the wave generation module is increased. In view of the characteristic that the geopolymer dissolution reaction is very sensitive to temperature, when the temperature is too high, the operating power of the load application module, which is the main heat source, is reduced to reduce heat generation, and the wave generation frequency of the wave generation module is increased to remove heat. (2) By monitoring the change in the cross-sectional area of ​​the test piece, when the cross-sectional area is low, if the traditional hydraulic pressure is applied, the actual stress per unit area will continue to increase with the deterioration process, causing the failure mode to become accelerated crushing. This reduces the output stress, improves the detection accuracy, and makes the detection environment closer to the actual situation. (3) By calculating the comprehensive ion detection confidence level, when the confidence level is higher than the threshold, the control module instructs the detection module to stop detection. When the bubbles caused by the wave generation module adhere to the surface of the ion selective electrode, producing a tip discharge or shielding effect, resulting in periodic spike noise in the online measured conductivity or ion concentration signal, the ion penetration detection is stopped to improve the accuracy of the detection results. Attached Figure Description

[0014] To facilitate understanding by those skilled in the art, the present invention will be further described below with reference to the accompanying drawings.

[0015] Figure 1 This is a block diagram of the control loop of the present invention; Figure 2 This is a schematic diagram of the overall structure of the present invention; In the picture: 1. Seawater circulation tank; 2. Load application module; 3. Wave generation module; 4. Loading frame; 5. Test piece. Detailed Implementation

[0016] To further illustrate the technical means and effects of the present invention in achieving its intended purpose, the following detailed description of the specific implementation methods, structures, features, and effects of the present invention, in conjunction with the accompanying drawings and preferred embodiments, is provided.

[0017] Please see Figure 1-2A test machine for simulating the degradation of geopolymer-stabilized soft soil by simulating tidal-load coupling includes a load application module 2, a wave generation module 3, a loading frame 4, a seawater circulation tank 1, and a control module. The control module is electrically connected to the load application module 2 and the wave generation module 3 respectively. The loading frame 4 is set in the seawater circulation tank 1 and is used to fix the test piece 5. The load application module 2 is used to apply a load to the test piece 5 from directly above. The wave generation module 3 is used to generate waves in the seawater circulation tank 1. Specifically, in this embodiment, the seawater circulation tank 1 is a rectangular tank. A loading frame 4 is provided at one end of the long side of the rectangular seawater circulation tank 1, and a wave generation module 3 is provided at the other end. The loading frame 4 is located inside the seawater circulation tank 1, and a clamp is provided on its top for fixing the test piece 5. A load application module 2 is provided directly above the loading frame 4. The load application module 2 includes a circulation component and a loading plate for contacting the test piece 5. In this embodiment, the circulation component is a hydraulic cylinder. The load application module 2 transmits the force output by the electric cylinder to the loading plate, and then applies a load to the test piece 5, which is located directly below it and fixed on the loading frame 4, through the loading plate. The load application module 2 periodically adjusts the output force of the circulation component so that the load changes periodically. The wave generation module 3 includes a vertical plate that can move closer to or further away from the loading frame 4. The lower end of the vertical plate is lower than the lower surface of the test piece 5. When the seawater in the seawater circulation tank 1 submerges the lower surface of the test piece 5 and comes into contact with the test piece 5, the wave generation module 3 periodically moves the vertical plate closer to or further away from the loading frame 4, pushing the seawater to scour the test piece 5, simulating the scouring effect of ocean waves on the test piece 5.

[0018] Optionally, seawater can be periodically injected into or discharged from the seawater circulation tank 1 to simulate the overall periodic change of seawater level; It also includes a detection module for detecting ion permeation; In actual experiments, although the system is designed to simulate the real tidal environment as much as possible, it is still affected by the inherent defects of the system itself. For example, during the operation of the load application module 2, its mechanical actuating parts will generate heat due to mechanical friction. This heat is conducted to the seawater in the seawater circulation tank 1 through the loading frame 4. In the degradation test of geopolymer solidified soft soil, the geopolymer dissolution reaction is very sensitive to temperature. Temperature changes will significantly affect the dissolution rate of aluminosilicates in the geopolymer and the equilibrium state of the condensation reaction, causing the temperature of the liquid environment around the specimen to rise, which will further accelerate the degradation process of the geopolymer solidified body, causing the measured ion penetration rate and strength decay data to deviate from the degradation law under real working conditions. Therefore, the solution needs to be fine-tuned at the execution end to compensate for the inherent defects in temperature. To this end, the invention further comprises a sensing module electrically connected to the control module, wherein the sensing module is configured to detect the temperature of the load application module 2 and upload the detected temperature to the control module, and when the control module determines that the temperature exceeds the temperature threshold, it instructs to reduce the load application cycle frequency and instructs to increase the wave making frequency of the wave making module 3; When the control module determines that the temperature of the load application module 2 exceeds the preset temperature threshold, on one hand, the control module reduces the cyclic loading frequency of the load application module 2 to reduce heat generation caused by mechanical friction; on the other hand, it increases the wave making frequency of the wave making module 3 to enhance the convective heat exchange efficiency of seawater in the seawater circulation tank 1 and accelerate heat dissipation. Thereby, the temperature fluctuation of seawater around the test piece is controlled within a reasonable range, the interference of temperature factors on the deterioration reaction of geopolymer is eliminated, and the ion penetration data and strength attenuation data measured in the test are closer to the actual deterioration law under the combined action of tide and load; Specifically, the sensing module is configured to detect the temperature W of the load application module 2 and upload it to the control module, the control module instructs to adjust the load application cycle frequency to 1-A1 times of the original frequency, and instructs to adjust the wave making frequency of the wave making module 3 to 1+A1 times of the original frequency, wherein A1=0.1x-0.1, x=W / W0, W0 is a preset temperature threshold, and W≥W0; when the control module determines that W<W0, the control module uses W=W0 to participate in the calculation; When W≤W0, x=1, the calculation result of A1 is 0, at this time, the wave making frequency or the load application cycle frequency is adjusted to 1±0=1 time of the original frequency, that is, no adjustment is performed; When W>W0, x>1, the calculation result of A1 is greater than 0, the control module adjusts the wave making frequency of the wave making module 3 to 1+A1 times the original frequency, which is an upward linear adjustment, and adjusts the load application cycle frequency to 1-A1 times the original frequency, which is a downward linear adjustment; At this time, the greater the deviation of temperature W from the threshold, the more the loading frequency decreases and the more the wave making frequency increases; the smaller the temperature deviation from the threshold, the smaller the adjustment amplitude. This realizes continuous proportional adjustment of loading frequency and wave making frequency according to the temperature deviation degree, avoids the impact of sudden on-off control on test continuity, and ensures that the treatment effect under different temperature deviation degrees meets the requirements; By arranging the sensing module to detect the temperature, and when it is determined that the temperature exceeds the threshold, instructing to reduce the load application cycle frequency and increase the wave making frequency of the wave making module 3, aiming at the characteristic that the dissolution reaction of geopolymer is very sensitive to temperature, when the temperature is too high, the operation power of the load application module 2, which is the main heat source, is reduced to lower heat generation, and the wave making frequency of the wave making module 3 is increased to take away heat.

[0019] During the ongoing degradation test of geopolymer-solidified soft soil, the surface of the specimen gradually peels off and becomes structurally loose under the coupled effects of seawater erosion and cyclic loading, resulting in a gradual decrease in the effective load-bearing cross-sectional area of ​​the specimen. Under these circumstances, if the load application module 2 continues to load according to the initially set oil pressure value, the actual stress per unit area will continue to increase with the degradation process. The failure mode of the specimen will gradually change from chemical degradation under simulated real working conditions to mechanical crushing, which will make it impossible for the measured strength decay data to distinguish between degradation caused by chemical erosion and failure caused by mechanical overload, resulting in distorted degradation evaluation results. Therefore, the sensing module is used to monitor the change in the cross-sectional area of ​​the current test piece 5 and upload the cross-sectional area to the control module. When the control module determines that the cross-sectional area is lower than the threshold, it reduces the applied pressure of the load application module 2. Specifically, the sensing module is equipped with four-way ranging sensors, which monitor the side of the test piece 5 from four directions. The farther the side of the test piece 5 is from the corresponding ranging sensor, the smaller the cross-sectional area. At this time, the actual stress level per unit area of ​​the test piece 5 remains relatively constant throughout the entire test cycle, thereby ensuring that the degradation process of the test piece is dominated by the coupling effect of seawater chemical erosion and cyclic loading, reducing the additional mechanical damage caused by stress increase, and improving the accuracy of degradation test. Specifically, the sensing module is used to upload the cross-sectional area J to the control module. When the control module determines that the cross-sectional area is lower than the threshold, it corrects the load of the load application module 2 to A2 times the original load, where A2 = J / J0 × c, c is a preset constant, and J0 is a preset cross-sectional area threshold. When the cross-sectional area is small and below the threshold, the value of A2=J / J0×c decreases synchronously. When the control module corrects the load of the load application module 2 to the original A2 times, it realizes the continuous proportional adjustment of the applied pressure. That is, when the measured cross-sectional area decreases relative to the threshold, the correction coefficient decreases accordingly, and the load decreases accordingly. Conversely, the load is maintained or restored, ensuring the stable output of stress per unit area. By monitoring the change in the cross-sectional area of ​​the current test piece 5, when the cross-sectional area is lower than the threshold, the applied pressure of the load application module 2 is reduced. When the cross-sectional area is low, if the load is applied according to the traditional hydraulic pressure setting, the actual stress per unit area will continue to increase with the deterioration process, causing the failure mode to change to accelerated crushing. Therefore, the output stress is reduced to improve the detection accuracy and make the detection environment closer to the actual situation.

[0020] During the online detection of ion permeation, the mechanical movement of the wave generation module 3 when generating waves will cause a large number of bubbles in the seawater. At the same time, the periodic loading of the load application module 2 will also cause mechanical vibration of the loading frame 4. When these bubbles and vibrations are transmitted to the ion selection electrode of the detection module, the bubbles will adhere to the electrode surface and generate a tip discharge or shielding effect. The mechanical vibration will cause the contact interface between the electrode and the seawater to change periodically. Both of these will cause periodic spike noise in the conductivity or ion concentration signals measured by the detection module. These spike noises are superimposed on the real ion concentration change signal, making it difficult for the control module to distinguish which are real ion permeation data and which are abnormal values ​​caused by interference. If the data containing interference is used directly for degradation evaluation, the measurement accuracy of key indicators such as ion permeation rate and permeation depth will be significantly reduced. Therefore, the sensing module is used to read the acceleration and turbidity of the wave generation module 3 and upload them to the control module. The control module calculates the comprehensive ion detection confidence level based on the acceleration and turbidity. When the control module determines that the confidence level is higher than the threshold, the control module instructs the detection module to stop detection. Specifically, the sensing module is electrically connected to a turbidity detector and an acceleration sensor, which are used to read the turbidity in the seawater circulation tank 1 and the acceleration of the wave generation module 3, respectively. At this point, two physical quantities directly related to the interference source, acceleration and turbidity, are introduced to calculate the comprehensive confidence level. When the acceleration is large, it indicates that the mechanical vibration is severe and the amount of bubbles generated is large. When the turbidity is high, it indicates that the suspended matter in the seawater is increased and the probability of bubble attachment is increased. The two together determine the reliability of the detection data at the current moment. Specifically, the control module calculates the comprehensive ion detection confidence level Z based on the acceleration a and the turbidity H, where Z = (a / a0 × d) × (H / H0 × e), where d and e are preset constants, H0 is a preset turbidity reference value, and a0 is a preset acceleration reference value. The operators (a / a0×d) and (H / H0×e) represent the normalized acceleration and turbidity, respectively, and the magnitudes of the two operators are positively correlated with the acceleration or turbidity. When one of the acceleration and turbidity is large, or both are large, the value of Z is larger. When the overall confidence level Z is higher than the threshold, it indicates that at least one of the acceleration and turbidity is large, and the current interference is serious. The control module actively stops the data acquisition of the detection module and resumes detection after the acceleration and turbidity drop to a lower level. This reduces the interference data caused by vibration and bubbles, so that the ion permeation data used for the final degradation evaluation can truly reflect the ion exchange and erosion depth of the geopolymer solidified body. The overall confidence level is calculated by multiplying the acceleration ratio and the turbidity ratio. An increase in either index will lead to an increase in the confidence level, thus achieving a synergistic assessment of the two interference factors. Furthermore, it also includes a control panel, which is electrically connected to the control module. The control panel is used to input the values ​​of W0, J0, a0, and H0. The operator can set the temperature threshold, cross-sectional area threshold, acceleration threshold, and turbidity threshold through the control panel according to the material characteristics and test requirements of different batches of geopolymer-stabilized soft soil, so that the testing machine can adapt to the deterioration test requirements of geopolymer-stabilized soft soil under different mix ratios and curing conditions.

[0021] Working principle and usage process of this invention: The geopolymer-solidified soft soil specimen to be tested is mounted on the loading frame 4 and placed in the seawater circulation tank 1. Temperature threshold W0, cross-sectional area threshold J0, acceleration threshold a0, turbidity threshold H0, and related constant parameters are set via the control panel. After starting the testing machine, the load application module 2 applies a cyclic load to the specimen 5 at the set frequency. The wave generation module 3 generates waves in the seawater circulation tank 1 to simulate a tidal environment. The detection module monitors changes in ion concentration in the seawater in real time to reflect ion permeation. During the test, the sensing module continuously collects the temperature W of the load application module 2 and uploads it to the control module. The control module calculates x = W / W0 and A1 = 0.1. x-0.1, when W exceeds W0, the loading frequency is adjusted to 1-A1 times the original and the wave-making frequency is adjusted to 1+A1 times the original; at the same time, the sensing module continuously monitors the real-time cross-sectional area J of the test specimen and uploads it to the control module. The control module calculates A2=J / J0×c and corrects the load to A2 times the original; in addition, the sensing module continuously reads the acceleration a of the load application module 2 and the seawater turbidity H and uploads it to the control module. The control module calculates Z=(a / a0×d)×(H / H0×e). When Z is higher than the preset threshold, the control module instructs the detection module to stop detection. After Z falls back below the threshold, detection resumes. This cycle continues until the test ends.

[0022] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present invention. Any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. A testing machine for simulating the degradation of geopolymer-stabilized soft soil by simulating tidal-load coupling, characterized in that: It includes a load application module, a wave generation module, a loading frame, a seawater circulation tank, a detection module, a sensing module, and a control module; The loading frame is set in the seawater circulation tank and used to load the test piece; The load application module is used to apply a load to the test piece; The wave-generating module is used to generate waves in a seawater circulation tank; The detection module is used to detect ion permeation in the seawater circulation tank; The sensing module is used to detect the temperature of the load application module and upload the data to the control module; The control module is communicatively connected to the load application module, wave generation module, detection module, and sensing module. When the control module determines that the temperature exceeds the temperature threshold, it instructs the load application cycle frequency to decrease and instructs the wave generation frequency of the wave generation module to increase.

2. The geopolymer solidification soft soil degradation test machine simulating tidal-load coupling according to claim 1, characterized in that: The sensing module is used to detect the temperature W of the load application module and upload it to the control module. When the temperature of the load application module exceeds the temperature threshold, the control module instructs the load application cycle frequency to be adjusted to 1-A1 times the original, and instructs the wave generation frequency of the wave generation module to be adjusted to 1+A1 times the original, where A1=0.1x-0.1, x=W / W0, and W0 is the preset temperature threshold.

3. The geopolymer solidification soft soil degradation test machine simulating tidal-load coupling according to claim 2, characterized in that: The sensing module is used to monitor the change in the cross-sectional area of ​​the current test piece and upload the cross-sectional area to the control module. When the control module determines that the cross-sectional area is lower than the cross-sectional area threshold, it reduces the applied pressure of the load application module.

4. The geopolymer solidification soft soil degradation test machine simulating tidal-load coupling according to claim 3, characterized in that: The sensing module is used to upload the cross-sectional area J to the control module. When the control module determines that the cross-sectional area J is lower than the cross-sectional area threshold, the control module corrects the load of the load application module to A2 times the original value, where A2 = J / J0 × c, c is a preset constant, and J0 is a preset cross-sectional area threshold.

5. The geopolymer solidification soft soil degradation test machine simulating tidal-load coupling according to claim 4, characterized in that: The sensing module is also used to read the acceleration and turbidity of the wave generation module and upload them to the control module. The control module calculates the comprehensive ion detection confidence level based on the acceleration and turbidity. When the control module determines that the confidence level is higher than the confidence level threshold, the control module instructs the detection module to stop detection.

6. The geopolymer solidification soft soil degradation testing machine simulating tidal-load coupling according to claim 5, characterized in that: The control module calculates the comprehensive ion detection confidence level Z based on the acceleration a and the turbidity H, where Z = (a / a0 × d) × (H / H0 × e), d and e are preset constants, H0 is a preset turbidity reference value, and a0 is a preset acceleration reference value.

7. The geopolymer solidification soft soil degradation test machine simulating tidal-load coupling according to claim 6, characterized in that: It also includes a control panel, which is electrically connected to the control module, and the control panel is used to input the values ​​of W0, J0, a0, and H0.

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