Dry-wet cycle test device for geotechnical sample

Abstract

The utility model discloses a dry-wet cycle test device for geotechnical samples, which comprises a closed box, a water permeable plate is horizontally arranged in the closed box, a plurality of sample placement points are arranged on the water permeable plate, and a pressure sensor is arranged at each sample placement point. A humidifying device and a heater are further arranged in the closed box above the water permeable plate, a fan is further arranged on the side wall of the closed box above the water permeable plate, and the fan, the pressure sensor, the humidifying device and the heater are all electrically connected with the central controller. According to the device disclosed by the utility model, after a sample is humidified to a preset weight through the spray head, the central controller stops humidifying after receiving a weight signal acquired by the pressure sensor, and then, after standing for 24 hours, a heating instruction is sent out, and the fan and the heater work simultaneously to evaporate water in the sample; when the weight signal fed back by the pressure sensor does not change, it is indicated that the moisture in the sample is completely volatilized, a heating stopping instruction is sent out, and a dry-wet cycle is obtained.

Description

Technical Field

[0001] This utility model relates to a dry-wet cycle test device for geotechnical samples, belonging to the field of road engineering technology. Background Technology

[0002] In actual road operation, roads inevitably experience rain and subsequent drying, forming a cyclical natural process. Rainwater seepage gradually softens the road's internal structural supports, weakening its structural stability. Conversely, when the road dries, uneven heating creates tensile stress, further exacerbating its deterioration. Therefore, conducting experimental research on wet-dry cycles is particularly important.

[0003] To address the aforementioned problems, the traditional wet-dry cycle test method involves: first, placing the geotechnical sample on permeable stone, sealing it in an acrylic chamber, and increasing the humidity inside the chamber using a humidifier until the sample reaches a predetermined weight. Then, the humidifier is turned off and the sample is left to stand for 24 hours. Subsequently, the sample is placed in an oven at a set temperature of 40°C for drying, and the sample is continuously weighed until it reaches the predetermined dry weight. This process is repeated for another 24 hours, completing one cycle. This process is repeated until the predetermined number of wet-dry cycles is achieved. While this method can simulate the wet-dry cycle process, it is time-consuming and labor-intensive, and errors can easily occur during the humidification process. Therefore, there is an urgent need in this field for equipment capable of automatically performing wet-dry cycle tests. Summary of the Invention

[0004] The purpose of this invention is to provide a wet-dry cycle testing device for geotechnical samples. This device automatically completes the humidification and drying cycle of geotechnical samples, and can also automatically filter and recycle wastewater.

[0005] The technical solution of this utility model is as follows: a dry-wet cycle test device for geotechnical samples, including a sealed box, a permeable plate horizontally arranged inside the sealed box, multiple sample placement points arranged on the permeable plate, a pressure sensor arranged at each sample placement point, a humidification device and a heater arranged inside the sealed box above the permeable plate, and a fan arranged on the side wall of the sealed box above the permeable plate. The fan, pressure sensor, humidification device and heater are all electrically connected to a central controller.

[0006] In the aforementioned wet-dry cycle test device for geotechnical specimens, the humidification device includes multiple nozzles, with one nozzle positioned directly above each pressure sensor, and each nozzle is electrically connected to the central controller.

[0007] In the aforementioned dry-wet cycle test device for geotechnical specimens, the bottom of the permeable plate is at a certain height from the bottom of the sealed box. The bottom of the sealed box is connected to the filter water tank via a pipe. The filter water tank is connected to the water storage tank via a pipe. The water storage tank is connected to the humidification device via a pipe. Water pumps are installed on the pipes connecting the boxes.

[0008] In the aforementioned dry-wet cycle test device for geotechnical specimens, the filter tank is equipped with a filter screen that divides it into left and right chambers, wherein the left chamber is connected to a sealed chamber via a pipe, and the right chamber is connected to a water storage tank via a pipe.

[0009] In the aforementioned dry-wet cycle test device for geotechnical specimens, a water-guiding slope is provided in the sealed box at the bottom of the permeable plate.

[0010] In the aforementioned dry-wet cycle test device for geotechnical specimens, the sealed box is made of plexiglass material.

[0011] In the aforementioned dry-wet cycle test apparatus for geotechnical specimens, the heater is a heater with a lampshade.

[0012] The beneficial effects of this invention are as follows: Compared with the prior art, the device of this invention humidifies the sample to a predetermined weight via a nozzle. Upon receiving the weight signal from the pressure sensor, the central controller stops humidification. After 24 hours of settling, a heating command is issued, and the fan and heater operate simultaneously to evaporate the moisture inside the sample. When the weight signal returned by the pressure sensor shows no change, it indicates that all the moisture inside the sample has evaporated, and a stop heating command is issued, thus completing one wet-dry cycle. Over time, as the number of cycles increases, the water consumption will also increase. The filter box next to the sealed chamber filters the excess water sprayed out and returns it to the storage tank via a water pump, thereby achieving the effect of wastewater recycling.

[0013] This invention realizes the drying and humidification process of geotechnical samples through a central controller, and realizes the recycling of wastewater through a water circulation system, thereby realizing the integrated dry and wet cycle test of geotechnical samples. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of the structure of this utility model;

[0015] Figure 2 This is a schematic diagram showing the arrangement of geotechnical samples on a permeable slab.

[0016] Figure 3 This is a schematic diagram of the humidification device.

[0017] Reference numerals: 1. Water storage tank; 2. Water pump; 3. Fan; 4. Humidification device; 5. Pressure sensor; 6. Geotechnical sample; 7. Heater; 8. Central controller; 9. Filter screen; 10. Filter water tank; 11. Water guide slope; 12. Sealed box; 13. Permeable plate; 14. Hole.

[0018] Reference numerals: Detailed Implementation

[0019] The present invention will be further described below with reference to the accompanying drawings and embodiments, but this should not be construed as limiting the present invention.

[0020] An embodiment of this utility model: A wet-dry cycle test device for geotechnical samples includes a sealed chamber 12, a permeable plate 13 horizontally arranged inside the sealed chamber 12, multiple sample placement points arranged on the permeable plate 13, a pressure sensor 5 arranged at each sample placement point, a humidification device 4 and a heater 7 arranged inside the sealed chamber 12 above the permeable plate 13, and a fan 3 arranged on the side wall of the sealed chamber 12 above the permeable plate 13. The fan 3, pressure sensor 5, humidification device 4 and heater 7 are all electrically connected to a central controller 8.

[0021] During use, the sealed chamber 12 is mainly used to place the geotechnical sample 6. Each sample placement point on the permeable plate 13 corresponds to one geotechnical sample 6. The bottom of the geotechnical sample 6 presses down on the pressure sensor 5, which is used to monitor the weight of the geotechnical sample 6 and transmit the monitoring signal to the central controller 8. The humidification device 4 is mainly used to humidify the geotechnical sample 6. The heater 7 is located on the top of the sealed chamber 12 and is mainly used for drying the geotechnical sample 6. The heater 7 can reach a maximum heating temperature of 80℃. Its main function is to simulate the drying process in the actual environment, and it can also increase the temperature inside the sealed chamber 12 according to actual needs, and work with the fan 3 to accelerate moisture evaporation. The fan 3 is located on the side wall of the sealed chamber 12 and is mainly used to accelerate the evaporation of moisture from the geotechnical sample 6 during drying. The central controller 8 is located on the sealed chamber 12 and mainly controls the internal temperature of the sealed chamber 12 and the humidification switch. The main purpose is to control the entire wet-dry cycle test process. Before each cycle, the predetermined humidification weight, the number of cycles, and the settling time after humidification of the geotechnical sample 6 are input. The weight signal fed back from the pressure sensor 5 controls whether humidification and drying stop. Specifically, when each geotechnical sample 6 reaches the predetermined weight, a stop command is sent to the humidification device 4. After settling for the designated time, a heating command is sent, and the heater 7 and fan 3 operate simultaneously until the weight signal value fed back from the pressure sensor 5 no longer changes, indicating that the moisture inside the geotechnical sample 6 has evaporated completely. The next cycle then begins.

[0022] The humidification device 4 includes multiple nozzles, with one nozzle positioned directly above each pressure sensor 5. Each nozzle is electrically connected to the central controller 8. This ensures that each geotechnical specimen 6 is humidified to a predetermined weight during the wet-dry cycle test. When a geotechnical specimen 6 reaches the predetermined weight, the central controller 8 stops spraying water from the nozzle directly above it. Meanwhile, the nozzles above other geotechnical specimens 6 continue spraying water until they reach the predetermined weight. The central controller 8 does not control all nozzles to stop spraying water simultaneously.

[0023] The bottom of the permeable plate 13 is at a certain height from the bottom of the sealed box 12. The bottom of the sealed box 12 is connected to the filter water tank 10 through a pipe. The filter water tank 10 is connected to the water storage tank 1 through a pipe. The water storage tank 1 is connected to the humidification device 4 through a pipe. Water pumps 2 are installed on the pipes connecting the boxes. When the geotechnical sample 6 is humidified, some water will fall through the holes 14 on the permeable plate 13 to the bottom of the sealed box 12. This part of the water is pumped into the filter water tank 10 through the water pump 2 and the pipe, and then pumped into the water storage tank 1 again through the water pump 2 and the pipe to replenish the water storage tank 1. The water storage tank 1 is used to provide the required water source for the humidification device 4.

[0024] The filter tank 10 is equipped with a filter screen 9, which divides it into left and right compartments. The left compartment is connected to the sealed tank 12 via a pipe, and the right compartment is connected to the storage tank 1 via a pipe. The filter screen 9 filters the humidified wastewater. The filtered wastewater then passes through the pipe connected to the storage tank 1, and is pumped into the storage tank 1 by the water pump 2 on the pipe for storage.

[0025] A water guide slope 11 is provided in the sealed box 12 at the bottom of the permeable plate 13, so that the excess wastewater when the sealed box 12 is humidified can be collected along the water guide slope 11 to the foot of the slope, and then easily pumped into the filter water tank 10 through the pipe connected to the filter water tank 10 by the water pump 2 on the pipe, so as to realize the recycling of wastewater.

[0026] The sealed box 12 is made of plexiglass, which facilitates observation of the inside of the box and allows the plexiglass to withstand high and low temperatures from -10 to 100℃. The sealed box 12 has a size of 70×50×40cm and is mainly used to place the geotechnical sample 6. The sealed box 12 has an openable door in front, which allows the geotechnical sample 6 to be placed into the box and removed after the test.

[0027] The heater 7 is a heater with a lampshade. The lampshade is mainly to prevent damage to the heater 7 during the humidification process.

[0028] The specific test steps for wet-dry cycle testing of geotechnical samples using the device of this invention are as follows:

[0029] First, the optimal moisture content for each mix ratio is obtained based on the compaction test, the required humidification range is predetermined, the moisture content after humidification is calculated, and then the weight of the geotechnical sample 6 after humidification can be calculated according to the formula and input into the central controller 8.

[0030] Open the sealed box 12, turn on the water circulation switch on the pipeline, place each geotechnical sample 6 on the pressure sensor 5 of the permeable plate 13, start the central controller 8, issue a humidification command, the nozzle of the humidification device 4 starts to work, the pressure sensor 5 monitors the weight of the geotechnical sample 6 in real time, when the monitored weight reaches the predetermined weight, the central controller 8 issues a stop humidification command, the nozzle stops working, and the geotechnical sample 6 begins to stand still.

[0031] The addition of pressure sensor 5 for real-time monitoring during the humidification process makes the test data more accurate, replacing the need for manual repeated handling and weighing of samples, making the operation more convenient and feasible.

[0032] After the settling period is complete, the central controller 8 issues a heating command, and the heater 7 and fan 3 work simultaneously to start simulating the sample drying process. The pressure sensor 5 monitors the weight of the geotechnical sample 6 in real time. When the weight signal value fed back by the pressure sensor 5 no longer changes, it indicates that the moisture in the geotechnical sample 6 has been evaporated. Then, the central controller 8 issues a stop heating command, and the fan 3 and heater 7 stop working.

[0033] This completes one wet-dry cycle. Then, based on the required number of wet-dry cycles input by the central controller 8, the next cycle begins. Finally, all devices inside the sealed box 12 cease operation after the cycle ends.

[0034] The required number of wet and dry cycles is controlled by the central controller 8, which not only saves time and effort, but also prevents inaccurate recording of the number of cycles due to too many geotechnical samples 6 during the test process.

[0035] Excess water sprayed from the nozzle enters the filter tank 10 through the water guide slope 11, and after being filtered by the filter screen 9, it is pumped back into the storage tank 1 by the water pump 2 to form a water circulation system for wastewater recycling.

[0036] The entire circulation system not only replaces the manual water addition process of the previous wet-dry cycle test device, but also collects, filters, and recycles wastewater, thus improving the practicality of the device.

Claims

1. A wet-dry cycle test apparatus for geotechnical specimens, characterized in that: It includes a sealed box (12), inside which a permeable plate (13) is horizontally arranged. Multiple sample placement points are set on the permeable plate (13), and a pressure sensor (5) is set at each sample placement point. A humidifying device (4) and a heater (7) are also set inside the sealed box (12) above the permeable plate (13). A fan (3) is also set on the side wall of the sealed box (12) above the permeable plate (13). The fan (3), pressure sensor (5), humidifying device (4) and heater (7) are all electrically connected to the central controller (8).

2. The wet-dry cycle test apparatus for geotechnical specimens according to claim 1, characterized in that: The humidification device (4) includes multiple nozzles, with one nozzle positioned directly above each pressure sensor (5), and each nozzle is electrically connected to the central controller (8).

3. The wet-dry cycle test apparatus for geotechnical specimens according to claim 1, characterized in that: The bottom of the permeable plate (13) is at a certain height from the bottom of the sealed box (12). The bottom of the sealed box (12) is connected to the filter water tank (10) via a pipe. The filter water tank (10) is connected to the water storage tank (1) via a pipe. The water storage tank (1) is connected to the humidification device (4) via a pipe. Water pumps (2) are installed on the pipes connecting the boxes.

4. The wet-dry cycle test apparatus for geotechnical specimens according to claim 3, characterized in that: The filter tank (10) is equipped with a filter screen (9) that divides it into left and right tanks. The left tank is connected to the sealed tank (12) via a pipe, and the right tank is connected to the water storage tank (1) via a pipe.

5. The wet-dry cycle test apparatus for geotechnical specimens according to claim 3, characterized in that: A water guide slope (11) is provided in the sealed box (12) at the bottom of the permeable plate (13).

6. The wet-dry cycle test apparatus for geotechnical specimens according to claim 1, characterized in that: The sealed box (12) is made of plexiglass.

7. The wet-dry cycle test apparatus for geotechnical specimens according to claim 1, characterized in that: The heater (7) is a heater with a lampshade.

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