Frozen soil in-situ freezing frost heaving force testing device

Abstract

The utility model discloses a frozen soil in-situ freezing frost heaving force testing device. The frozen soil in-situ freezing frost heaving force testing device comprises a temperature control box, a soil sample box arranged in the temperature control box, a sensor arranged in the soil sample box, a data acquisition instrument electrically connected with the sensor and a computer electrically connected with the data acquisition instrument, the frozen soil in-situ freezing frost heaving force testing device is simple in structure, overall cooling is achieved through the temperature control box, and based on the defects of an existing freezing and cooling mode, uniform in-situ freezing of a soil body is creatively achieved through the cooling mode that the sealed soil sample box is completely immersed in cold liquid; the actual temperature and the set temperature are highly consistent, the accuracy of the test structure is higher, and the method has important significance for researching the development and change rule of the soil frost heaving force.

Description

Technical Field

[0001] The utility model relates to the field of frozen soil detection equipment, in particular to a frozen soil in-situ freezing and frost heaving force testing device. Background Art

[0002] During the freezing process of soil, the water phase in the soil turns into ice and increases in volume by 9%, causing frost heave of the soil. Frost heave causes buildings to bear greater stress, namely frost heave force. Frost heave force is an important cause of frost damage, causing uneven foundation lifting, pipe warping, uneven road surface, mine wall deformation, and tunnel lining deformation or even damage. Soil frost heave is formed by in-situ frost heave and partial freezing heave. In-situ frost heave is the volume expansion caused by in-situ freezing of pore water, and partial freezing heave is caused by water migration during the freezing process. When the temperature changes rapidly, the soil freezing is considered to be in-situ freezing, and there is basically no water migration inside the soil.

[0003] At present, most of the traditional test methods for soil frost heave force are to test the overall frost heave force by installing a force measuring device on the top of the soil sample under the condition of water migration through a one-way freezing test. There is no test method and device for the frost heave force caused by in-situ freezing inside the soil. In addition, most frost heave tests use one-way freezing, two-way freezing and other methods; most of the above methods use upper and lower cold bath plates to cool down, but this cooling method has cold loss during the cooling process, resulting in the set temperature not matching the actual temperature and the in-situ freezing of the soil sample cannot be achieved. Utility Model Content

[0004] The utility model aims to provide a frozen soil in-situ freezing frost heaving force testing device, which solves the problem of frozen soil in-situ freezing frost heaving force detection.

[0005] The utility model is implemented as follows: a frozen soil in-situ freezing and frost heaving force testing device, the frozen soil in-situ freezing and frost heaving force testing device comprises: a temperature control box, a soil sample box placed inside the temperature control box, a sensor placed inside the soil sample box, a data acquisition instrument electrically connected to the sensor, and a computer electrically connected to the data acquisition instrument. The temperature control box is used to cool down the cold liquid as a whole, the cooling speed is fast, and the temperature control is more precise.

[0006] A further technical solution of the utility model is: the temperature control box is filled with cold liquid, and the soil sample box is cooled by the cold liquid.

[0007] A further technical solution of the utility model is: the soil sample box comprises: a box body (2), and a top plate arranged at the top of the box body, the box body is a square hollow box body, the interior of which is used to hold the soil sample, and the soil sample is sealed by the top plate and the box body.

[0008] A further technical solution of the utility model is: a wing plate is provided on the top of the box body, and mounting holes are provided at four corners of the top of the box body, and the box body is fixed and sealed through the mounting holes and bolt holes at the four corners of the wing plate.

[0009] A further technical solution of the utility model is: a nano rubber strip is arranged on the top of the box body, and a support rod is arranged on the bottom end of the box body.

[0010] A further technical solution of the utility model is: a first wiring hole is provided on the top plate, a second wiring hole is provided on the side wall of the box body, and holes are provided on the top plate and the box body respectively for routing sensor data lines.

[0011] A further technical solution of the utility model is: bolt holes corresponding to the mounting holes are arranged at four corners of the top plate, and the bolt holes are the same in size and corresponding in position to the mounting holes.

[0012] A further technical solution of the utility model is: the sensor is a temperature-pressure sensor, six of which are arranged, with a total of 6 temperature-pressure sensors, sensor 10-1 is arranged at the center of the soil sample, sensors 10-2, 10-3, 10-4, and 10-5 are arranged on the side walls, and sensor 10-6 is arranged on the bottom. By monitoring the frost heave force and temperature development and change laws at three positions: the center, the side walls, and the bottom, it is possible to compare whether the in-situ freezing frost heave force inside the soil is evenly distributed and calculate the temperature field changes of the soil during the freezing process.

[0013] The beneficial effects of the utility model: the frozen soil in-situ freezing frost heaving force testing device of the utility model has a simple structure and is cooled overall by a temperature control box. Based on the shortcomings of current freezing and cooling methods, the device pioneered the realization of uniform in-situ freezing of the soil through a cooling method in which a sealed soil sample box is completely immersed in cold liquid; the actual temperature is highly consistent with the set temperature, and the test structure is more accurate, which is of great significance for studying the development and change law of soil frost heaving force. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a schematic diagram of the overall structure of a frozen soil in-situ freezing heaving force testing device provided by the utility model;

[0015] Figure 2 It is a structural schematic diagram of a soil sample box of a frozen soil in-situ freezing and frost heaving force testing device provided by the utility model;

[0016] Figure 3 The utility model discloses a schematic diagram of the installation position of a sensor of a frozen soil in-situ freezing and heaving force testing device. DETAILED DESCRIPTION

[0017] The following is an explanation of the implementation of the present invention through specific examples, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific implementations, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present invention.

[0018] It should be noted that the structures, proportions, sizes, etc. illustrated in the drawings of the present specification are only used to match the contents disclosed in the specification for people familiar with the technology to understand and read, and are not used to limit the limiting conditions for the implementation of the present utility model, so they have no substantial technical significance. Any modification of the structure, change of the proportion relationship or adjustment of the size, without affecting the effects and purposes that can be achieved by the present utility model, should still fall within the scope of the technical contents disclosed by the present utility model. At the same time, the terms such as "upper", "lower", "left", "right", "middle" and "one" quoted in the present specification are only for the convenience of description, and are not used to limit the scope of the implementation of the present utility model. The change or adjustment of the relative relationship, without substantial change of the technical contents, should also be regarded as the scope of the implementation of the present utility model.

[0019] Embodiment 1: Figure 1-Figure 3A frozen soil in-situ freezing and frost heaving force testing device is shown, which comprises: a temperature control box, a soil sample box placed inside the temperature control box, a sensor placed inside the soil sample box, a data acquisition instrument electrically connected to the sensor, and a computer electrically connected to the data acquisition instrument. The temperature control box is used to cool down the cold liquid as a whole, and the cooling speed is fast and the temperature control is more accurate. The temperature control box is filled with cold liquid, and the soil sample box is cooled by the cold liquid. The soil sample box comprises: a box body 2, A top plate 1 is arranged at the top of the box body 2. The box body is a square hollow box body, and the interior is used to hold soil samples. The soil samples are sealed by the top plate and the box body; a wing plate 5 is arranged on the top of the box body 2, and mounting holes 7 are arranged at the four corners of the top of the box body 2. The mounting holes at the four corners of the wing plate 5 and the bolt holes 4 are fixed and sealed by bolts; a nano rubber strip 6 is arranged on the top of the box body 2, and a support rod 8 is arranged at the bottom of the box body 2; a first wiring hole 3 is arranged on the top plate 1, and a second wiring hole 7 is arranged on the side wall of the box body 2. Wire hole 9, the top plate and the box body are respectively provided with holes for routing sensor data lines; the four corners of the top plate 1 are provided with bolt holes 4 corresponding to the mounting holes 7, and the bolt holes are of the same size and corresponding in position to the mounting holes; the sensor is a temperature-pressure sensor, and six temperature-pressure sensors are provided, with a total of 6 temperature-pressure sensors arranged, sensor 10-1 is arranged at the center of the soil sample, sensors 10-2, 10-3, 10-4, and 10-5 are arranged on the side walls, and sensor 10-6 is arranged at the bottom. By monitoring the frost heaving force and temperature development and change laws at the three positions of the center, the side walls and the bottom, the function of comparing whether the in-situ freezing frost heaving force inside the soil is evenly distributed and the temperature field change of the soil during the freezing process can be calculated; the in-situ freezing frost heaving force testing device of the utility model has a simple structure, and the actual temperature is highly consistent with the set temperature through the overall cooling of the temperature control box, and the test structure has higher accuracy, which is of great significance for studying the development and change laws of the frost heaving force of the soil.

[0020] Specific configuration model:

[0021] Temperature control box: TMS8035 temperature calibration tank -30~+90℃, temperature fluctuation ±0.05℃, cold liquid is ethanol with concentration>75°, and the height of the cold liquid can be adjusted to the required height.

[0022] Temperature-pressure sensor: including the customized PB11F-D17-1MPa temperature-pressure sensor, which can realize the synchronous measurement of temperature and frost heave force at the measuring point. A total of 6 temperature-pressure sensors are arranged, 10-1 is arranged at the center of the soil sample, 10-2, 10-3, 10-4, 10-5 are arranged on the side walls, and 10-6 is arranged at the bottom. By monitoring the frost heave force and temperature development and change laws at the center, side walls and bottom, it is possible to compare whether the in-situ freezing frost heave force inside the soil is evenly distributed and calculate the temperature field changes of the soil during the freezing process. Among them, the four temperature-pressure sensors arranged on the side wall can realize the function of calibrating the frost heave force at the side wall, and the frost heave force at the side wall can be calculated by the following formula:

[0023]

[0024]

[0025] Where P2~P5 are the force readings of the temperature-pressure sensor 10-2~10-5 respectively, S 传感器 is the force measuring surface area of ​​the sensor, δ 侧 is the calibrated frost heave force at the side wall.

[0026] During measurement: Before measuring the frost heave force, first assemble the various parts of the device as described above, perform waterproof treatment, place it in cold liquid for several hours, and monitor whether the waterproofing meets the standard. Then first install the bottom 10-6 temperature-pressure sensor and pass the data line through hole 9. Then load the soil sample into the box body 2 in layers, compact and scrape each layer before adding the next layer of soil. After the soil reaches the sensor height at the side wall and the center, bury the sensor, and continue to load the soil in layers to the top of the box body 2. Scrape the top soil flat, and the sensor 10-1~10-5 data lines pass through the wiring hole 3 of the top plate 1. Fix the top plate 1 with the wing plate 5 by screws and tighten until the nano rubber strip 6 is compressed. Seal the data line with the wiring hole 3 and the second wiring hole 9 with waterproof glue. Connect the data line to the data acquisition instrument, power on the data acquisition instrument and connect it to the computer to observe whether the initial values ​​of the sensor temperature and pressure are normal. Then put the entire soil sample box into the temperature control box, so that the cold liquid completely immerses the soil sample box and is higher than a certain height, set the cold liquid temperature to 0℃, let it stand and observe the real-time temperature of the side wall and the center point. After the center point temperature is close to 0℃ and stabilizes, adjust the cold liquid temperature to the test temperature. The purpose is to make the soil reach 0℃ as a whole before freezing, to ensure that the force collected by the pressure sensor is completely generated by the freezing of the soil.

[0027] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A frozen soil in-situ freezing heaving force testing device, characterized in that: The frozen soil in-situ freezing heaving force testing device comprises: a temperature control box, a soil sample box placed inside the temperature control box, a sensor placed inside the soil sample box, a data acquisition instrument electrically connected to the sensor, and a computer electrically connected to the data acquisition instrument; the temperature control box is filled with cold liquid; the soil sample box comprises: a box body (2), a top plate (1) arranged at the top of the box body (2); a wing plate (5) is arranged at the top of the box body (2), and mounting holes (7) are arranged at the four corners of the top of the box body (2); a nano rubber strip (6) is arranged at the top of the box body (2), and a support rod (8) is arranged at the bottom of the box body (2); a first wiring hole (3) is arranged on the top plate (1), and a second wiring hole (9) is arranged on the side wall of the box body (2); bolt holes (4) corresponding to the mounting holes (7) are arranged at the four corners of the top plate (1); the sensor is a temperature-pressure sensor, and six temperature-pressure sensors are arranged.

Images