The Frost Heave Test Chamber is an indispensable core experimental device for studying the frost heave characteristics of soil and assessing the frost heave risk of engineering projects

Low-temperature frozen soil frost heave tester

Model:TGSYA-1

I. Product Introduction

The TGSYA-1 series low-temperature frozen soil frost heave rate tester is developed and manufactured by our factory according to the technical requirements of T0193-2019 "Test Method for Resilient Modulus under Freeze-Thaw Cycles" in JTG 3430-2020 "Specifications for Geotechnical Testing of Highways". It is mainly used to determine the resilient modulus of soil samples after freeze-thaw cycles to evaluate the bearing capacity of subgrade soil under long-term freeze-thaw influence.

The equipment consists of a test chamber, a constant temperature chamber, a temperature control system, and a moisture supply system. It can achieve precise control of the freeze-thaw environment, temperature changes, and moisture content conditions, ensuring the accuracy and repeatability of test data. Furthermore, this equipment conforms to international standards BS 812-124:2009 and JGS 0172. It possesses the technical performance required by the international market and can be used in geotechnical testing fields exported to many countries.

II. Technical Parameters:

1. Temperature Control Range: -30℃ to +50℃

2. Temperature Control Accuracy: ±1℃

3. Fluctuation Range: ±0.1℃

4. Freezing Temperature: -15℃

5. Freezing Time: 0-9999 hours (adjustable)

6. Melting Temperature: 15±℃

7. Melting Time: 0-9999 hours (adjustable)

8. Freeze-Thaw Cycles: 0-9999 times (adjustable)

9. Subgrade soil with a particle size not exceeding 5mm

10. Power Supply: 220V 50Hz

11. Weight: 300kg

III. Test Procedure

1. Sample Installation

Take the freeze-thaw sample and sample cylinder and install them together on the bottom plate of the freeze-thaw test chamber. Place a piece of filter paper on the top and bottom of the sample, then place the top plate on top. Gently press the top plate to ensure close contact between the sample and the top and bottom plates.

2. Piping Connection

Connect the top and bottom plate heat exchangers to the coolant piping using silicone tubing.

3. Setting the Moisture Supply Mode

First, turn on the moisture supply switch and purge the air from the bottom plate. When there is external moisture supply to the subgrade soil, the test state is an open system, and the moisture supply switch is set to open; when there is no external moisture supply to the subgrade soil, the test state is a closed system, and the moisture supply switch is set to closed.

4. Close the Chamber Door

5. Freezing Process

Set the chamber temperature to +2℃, the top plate temperature to the freezing temperature (selected according to the freezing index of the project location), and the bottom plate temperature to +2℃. Simultaneously turn on the temperature control switches of the chamber and the upper and lower heat exchangers. The top plate heat exchanger is cooled to the target freezing temperature at a temperature change rate of 20℃/h, with a freezing time not less than 48 hours; the bottom plate and constant temperature chamber are controlled at a constant temperature.

6. Melting Process

Set the constant temperature chamber temperature to +2℃, the top plate temperature to +15℃, and the bottom plate temperature to +2℃ respectively, while simultaneously adjusting the temperature control switches of the chamber and the upper and lower heat exchangers. The top plate heat exchanger is heated to the target thawing temperature at a temperature change rate of 20℃/h, with a thawing time not less than 12 hours; the bottom plate and constant temperature chamber are controlled at a constant temperature.

7. Freeze-Thaw Cycle

Steps 4.5 to 4.6 above constitute one complete freeze-thaw cycle. Repeat steps 4.5 to 4.6 of this test until 5 freeze-thaw cycles are completed. Note: The number of freeze-thaw cycles for the sample can be determined based on the soil sample and actual engineering conditions, but the number of cycles must be indicated in the report.

8. After the freeze-thaw cycle test, turn off all temperature control switches, open the chamber door, and disconnect the circulation tubing. Carefully remove the specimen from the freeze-thaw cycle test apparatus after the freeze-thaw cycle. Remove any surface water and allow it to stand for 10 minutes for subsequent tests.

9. Test the resilience modulus ET of the specimen after freeze-thaw cycles. Depending on the test conditions, the test procedure should be performed according to the requirements of test T 0135 or T 0136 of this specification. The method for testing the resilience modulus before and after freeze-thaw cycles should be consistent.

IV. Results Processing

The method for calculating the resilience modulus of the specimen after freeze-thaw cycles should be performed according to the requirements of test T 0135 or T 0136 of this specification and should be consistent with the calculation method for the specimen before freeze-thaw cycles.