Device and method for measuring adhesion of frozen soil

Abstract

The present invention provides a device and method for measuring the adhesion of frozen soil containing ice. The device includes a heat-insulating cotton layer, a box, a heat-insulating cover plate, a fan, a heat-insulating plate, a motor, a stirring rod, a blade, a steel basin, a steel plate, a screw, a wooden barrel (with holes) and a plastic wrap; the side wall of the box is equipped with a fan and a steel plate; a constant temperature environment is provided by cooling with a fan; the motor drives the stirring rod to stir the frozen soil blocks in the steel basin to make it viscous; and the adhesion of frozen soil containing ice adhering to the stirring rod can be studied. According to the ice content per unit mass of frozen soil samples and the adhesion per unit mass of frozen soil containing ice, the relationship between the ice content of soil samples with different water contents after different freezing times and the adhesion of frozen soil can be obtained, thereby providing an analytical basis for the prevention of shield mud cakes in frozen soil layers.

Description

Technical Field

[0001] The invention relates to a device and method for measuring adhesion of frozen soil containing ice, and belongs to the technical field of model test of adhesion of frozen soil containing ice. Background Art

[0002] During the tunneling process, shield machines often encounter the phenomenon of soil adhering to or blocking the shield cutterhead. Adhesion is the attraction between soil and structure through the adsorption of water molecules. During the cutting and extrusion of the shield cutterhead in the soil, it is very easy to form a high-strength mud cake at the center of the cutterhead, which gradually spreads to the surroundings, causing the cutterhead and tool to be wrapped and unable to effectively cut the soil layer, which reduces the efficiency of shield tunneling and greatly increases the construction period and construction cost. With the development of transportation infrastructure, more shield tunnel projects will pass through frozen soil areas, making it necessary to study the adhesion of frozen soil.

[0003] The search found that Xiao Yuhao used a self-made traction transmission adhesion test device in "Indoor test of reducing adhesion of clay by electroosmosis method" to measure the maximum adhesion of clay at different water contents; Liu Cheng used a self-designed adhesion pull test device in "Effect of soil moisture content and metal corrugated surface on interface adhesion" to achieve the corrugated convex effect of the measuring cone surface by winding metal wire, and analyzed the influence of different corrugated convex degrees and soil moisture content changes on the interface adhesion characteristics. The existing test devices are mainly used to measure the adhesion between the metal interface and the soil with different moisture contents, and there is a lack of research on the adhesion characteristics of frozen soil.

[0004] Therefore, the existing technology is unable to measure the adhesion of ice-containing frozen soil in a low-temperature environment, and it is even more impossible to determine the impact of the ice content on the adhesion of frozen soil. Summary of the invention

[0005] The purpose of the present invention is to study the influence of the ice content in frozen soil on the adhesion, and provide a device and method for measuring the adhesion of frozen soil containing ice. A constant temperature box is used to maintain the ice content, and the adhesion amount is measured by a motor and a stirring rod. The continuous rotation of the stirring rod can fully contact the ice-containing frozen soil, thereby improving the accuracy of the adhesion amount measurement and solving the problem of measuring the adhesion of frozen soil containing ice.

[0006] A device for measuring adhesion of frozen soil, comprising a constant temperature box, a stirring unit, a fixing unit, a temperature control unit and a sample preparation unit;

[0007] The thermostatic box comprises a box body 2, a heat-insulating cotton layer 1, a heat-insulating cover plate 3 and a heat-insulating plate 5;

[0008] The stirring unit includes a motor 6, a stirring rod 7 and a steel basin 10;

[0009] The fixing unit includes a steel plate 11, a screw 12 and a screw 16;

[0010] The temperature control unit includes a fan 4;

[0011] The sample preparation unit includes a wooden barrel (with holes) 13, a plastic wrap 14 and soil 15;

[0012] The box body 2 is provided with a stirring unit and a fan 4; the fan 4 is fixed on the side wall of the box body 2; the stirring unit is respectively composed of a motor 6, a stirring rod 7 and a steel basin 10 from top to bottom, the bottom of the motor 6 is fixed to the upper part of the steel plate 11 by screws 16, the stirring rod 7 is connected to the motor 6 and can be removed, the stirring rod 7 is provided with blades 17, the steel basin 10 is fixed to the bottom of the box body 2, and the stirring rod 7 is located inside the steel basin 10 after installation and the height is adjustable; the steel plate 11 is fixed to the side wall of the box body 2 by screws 12; the inner wall of the box body 2 is provided with a heat preservation plate 5; the top of the box body 2 is provided with a heat preservation cover plate 3; the top of the heat preservation cover plate 3 is provided with a heat preservation cotton layer 1;

[0013] The inner wall of the wooden barrel (with holes) 13 is paved with a layer of preservative film 14; soil 15 is wrapped inside the preservative film 14.

[0014] The method for measuring the adhesion of frozen soil is connected with the above-mentioned device for measuring the adhesion of frozen soil, and the specific steps are as follows:

[0015] ① Remove the stirring rod 7 installed on the motor 6 and weigh it initially, and the mass is recorded as m′;

[0016] ② Turn on the fan 4, add an appropriate amount of water 9 into the steel basin 10, and keep the temperature in the thermostat box at a constant temperature of 0.1°C;

[0017] ③Preparing a soil sample with a specific moisture content w: laying a plastic wrap 14 on the inner wall of a wooden barrel (with holes) 13; placing the soil with a specific moisture content w in the plastic wrap 14, and compacting it layer by layer; when the soil fills the wooden barrel (with holes) 13, covering it with the plastic wrap 14, and completely wrapping the soil sample;

[0018] ④ After the soil sample with a specific moisture content w is frozen for a certain period of time t, the soil sample is cut into frozen soil blocks 8 with a diameter of 1 cm to 2 cm using a soil cutter; the frozen soil block 8 with a mass of M1 is weighed and placed in a steel basin 10; the frozen soil block 8 with a mass of M2 is weighed for nuclear magnetic resonance testing.

[0019] ⑤ Turn on the motor 6, stir thoroughly for 3 minutes, then remove the stirring rod 7 with frozen soil containing ice and weigh it, and record the mass as m″; the adhesion amount K of unit mass of frozen soil containing ice is obtained by the calculation formula K=(m″-m′) / M1, and the adhesion of frozen soil with different ice content is determined.

[0020] ⑥ Use nuclear magnetic resonance technology to measure the unfrozen water content per unit mass of frozen soil samples, and thus obtain the ice content per unit mass of frozen soil samples.

[0021] ⑦ Repeat steps ③ to ⑥ to obtain the ice content per unit mass of frozen soil samples and the adhesion amount K per unit mass of frozen soil containing ice after different freezing times t for soil samples with different moisture contents w.

[0022] Furthermore, according to the ice content per unit mass of frozen soil samples and the adhesion K of unit mass of ice-containing frozen soil, the relationship between the ice content of soil samples with different moisture contents w after different freezing times t and the adhesion of frozen soil can be obtained, thereby providing an analytical basis for the prevention of mud cake formation in shield structures in frozen soil strata.

[0023] Beneficial Effects

[0024] The present invention provides a device and method for measuring the adhesion of frozen soil containing ice. The device comprises a thermal insulation cotton layer 1, a box body 2, a thermal insulation cover plate 3, a fan 4, a thermal insulation plate 5, a motor 6, a stirring rod 7, a steel basin 10, a steel plate 11, a screw 12, a wooden barrel (with holes) 13, a plastic wrap 14, a screw 16 and a blade 17; the side wall of the box body is installed with a fan and a steel plate; a constant temperature environment is provided by cooling with the fan; the motor is fixed to the steel plate by screws; the motor drives the stirring rod to stir the frozen soil blocks in the steel basin to make them viscous; by measuring the mass of the frozen soil containing ice adhered to the stirring rod, the relationship between the ice content of soil samples with different moisture contents w after different freezing times t and the adhesion of the frozen soil can be obtained.

[0025] The advantages of the present invention are as follows:

[0026] 1) By controlling a stable low-temperature environment, the ice content is ensured not to change significantly before and after stirring, and the adhesion amount of frozen soil corresponding to the ice content can be accurately determined;

[0027] 2) By measuring frozen soil with different ice contents, we can study the influence of different ice contents on the adhesion of frozen soil. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 It is a schematic diagram of the structure of the device for measuring the adhesion of frozen soil containing ice according to the present invention;

[0029] Figure 2 It is a structural schematic diagram of the frozen soil sample preparation device of the present invention;

[0030] Figure 3 is a schematic structural diagram of the stirring rod of the present invention;

[0031] Explanation of the numbers: thermal insulation cotton layer 1, box body 2, thermal insulation cover 3, fan 4, thermal insulation board 5, motor 6, stirring rod 7, frozen soil block 8, water 9, steel basin 10, steel plate 11, screw 12, wooden barrel (with holes) 13, plastic wrap 14, soil 15, screw 16 and blade 17. DETAILED DESCRIPTION

[0032] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0033] like Figures 1 to 3 As shown, the device for measuring adhesion of frozen soil includes a constant temperature box, a stirring unit, a fixing unit, a temperature control unit and a sample preparation unit;

[0034] The thermostatic box comprises a box body 2, a heat-insulating cotton layer 1, a heat-insulating cover plate 3 and a heat-insulating plate 5;

[0035] The stirring unit includes a motor 6, a stirring rod 7 and a steel basin 10;

[0036] The fixing unit includes a steel plate 11, a screw 12 and a screw 16;

[0037] The temperature control unit includes a fan 4;

[0038] The sample preparation unit includes a wooden barrel (with holes) 13, a plastic wrap 14 and soil 15;

[0039] The box body 2 is provided with a stirring unit and a fan 4; the fan 4 is fixed on the side wall of the box body 2; the stirring unit is respectively composed of a motor 6, a stirring rod 7 and a steel basin 10 from top to bottom, the bottom of the motor 6 is fixed to the upper part of the steel plate 11 by screws 16, the stirring rod 7 is connected to the motor 6 and can be removed, the stirring rod 7 is provided with blades 17, the steel basin 10 is fixed to the bottom of the box body 2, and the stirring rod 7 is located inside the steel basin 10 after installation and the height is adjustable; the steel plate 11 is fixed to the side wall of the box body 2 by screws 12; the inner wall of the box body 2 is provided with a heat preservation plate 5; the top of the box body 2 is provided with a heat preservation cover plate 3; the top of the heat preservation cover plate 3 is provided with a heat preservation cotton layer 1;

[0040] The inner wall of the wooden barrel (with holes) 13 is paved with a layer of preservative film 14; soil 15 is wrapped inside the preservative film 14.

[0041] The method for measuring the adhesion of frozen soil is connected with the above-mentioned device for measuring the adhesion of frozen soil, and the specific steps are as follows:

[0042] ① Remove the stirring rod 7 installed on the motor 6 and weigh it initially, and the mass is recorded as m′;

[0043] ② Turn on the fan 4, add an appropriate amount of water 9 into the steel basin 10, and keep the temperature in the thermostat box at a constant temperature of 0.1°C;

[0044] ③Preparing a soil sample with a specific moisture content w: laying a plastic wrap 14 on the inner wall of a wooden barrel (with holes) 13; placing the soil with a specific moisture content w in the plastic wrap 14, and compacting it layer by layer; when the soil fills the wooden barrel (with holes) 13, covering it with the plastic wrap 14, and completely wrapping the soil sample;

[0045] ④ After the soil sample with a specific moisture content w is frozen for a certain period of time t, the soil sample is cut into frozen soil blocks 8 with a diameter of 1 cm to 2 cm using a soil cutter; the frozen soil block 8 with a mass of M1 is weighed and placed in a steel basin 10; the frozen soil block 8 with a mass of M2 is weighed for nuclear magnetic resonance testing.

[0046] ⑤ Turn on the motor 6, stir thoroughly for 3 minutes, then remove the stirring rod 7 with frozen soil containing ice and weigh it, and record the mass as m″; the adhesion amount K of unit mass of frozen soil containing ice is obtained by the calculation formula K=(m″-m′) / M1, and the adhesion of frozen soil with different ice content is determined.

[0047] ⑥ Use nuclear magnetic resonance technology to measure the unfrozen water content per unit mass of frozen soil samples, and thus obtain the ice content per unit mass of frozen soil samples.

[0048] ⑦ Repeat steps ③ to ⑥ to obtain the ice content per unit mass of frozen soil samples and the adhesion amount K per unit mass of frozen soil containing ice after different freezing times t for soil samples with different moisture contents w.

[0049] The above is only a preferred implementation of the technology of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and substitutions can be made without departing from the technical principles of the present invention. These improvements and substitutions should also be regarded as the scope of protection of the present invention.

Claims

1. A method for determining the adhesion of frozen soil, characterized in that: The specific steps are as follows: ① Remove the stirring rod (7) mounted on the motor (6) and weigh it initially, and record the mass as m′; ② Turn on the fan (4), add an appropriate amount of water (9) into the steel basin (10), and keep the temperature in the thermostat box at a constant temperature of 0.1°C; ③ Preparing a soil sample with a specific moisture content w: laying a plastic wrap (14) on the inner wall of a wooden barrel with holes (13); placing soil with a specific moisture content w in the plastic wrap (14) and compacting it layer by layer; when the soil fills the wooden barrel with holes (13), covering it with the plastic wrap (14) to completely wrap the soil sample; ④ After the soil sample with a specific moisture content w is frozen for a certain period of time t, the soil sample is cut into frozen soil blocks (8) with a diameter of 1 cm to 2 cm using a soil cutter; the frozen soil block (8) with a mass of M1 is weighed and placed in a steel basin (10); the frozen soil block (8) with a mass of M2 is weighed and subjected to a nuclear magnetic resonance test; ⑤ Turn on the motor (6), stir thoroughly for 3 minutes, remove the stirring rod (7) with frozen soil containing ice adhered to it and weigh it, and record the mass as m″; the adhesion amount K of unit mass of frozen soil containing ice is obtained by the calculation formula K=(m″-m′) / M1, and the adhesion of frozen soil containing ice with different ice content is determined; ⑥ Use nuclear magnetic resonance technology to measure the unfrozen water content per unit mass of frozen soil samples, thereby obtaining the ice content per unit mass of frozen soil samples; ⑦ Repeat steps ③ to ⑥ to obtain the ice content per unit mass of frozen soil samples and the adhesion amount K per unit mass of frozen soil containing ice after different freezing times t for soil samples with different moisture contents w.

2. The method according to claim 1, characterized in that According to the ice content per unit mass of frozen soil samples and the adhesion K of unit mass of frozen soil containing ice, the relationship between the ice content of soil samples with different moisture contents w after different freezing times t and the adhesion of frozen soil can be obtained, thus providing an analytical basis for the prevention of mud cake formation in shield structures in frozen soil strata.

3. A device for measuring adhesion of frozen soil, characterized in that: The method according to claim 1 is used for determination, comprising a constant temperature box, a stirring unit, a fixing unit, a temperature control unit and a sample preparation unit; The thermostatic box comprises a box body (2), a thermal insulation cotton layer (1), a thermal insulation cover plate (3) and a thermal insulation plate (5); The stirring unit comprises a motor (6), a stirring rod (7) and a steel basin (10); The fixing unit comprises a steel plate (11), a screw (12) and a screw (16); The temperature control unit comprises a fan (4); The sample preparation unit comprises a wooden barrel with holes (13), a plastic wrap (14) and soil (15); The box (2) is provided with a stirring unit and a fan (4); the fan (4) is fixed on the side wall of the box (2); the stirring unit comprises, from top to bottom, a motor (6), a stirring rod (7), and a steel basin (10); the bottom of the motor (6) is fixed to the upper part of the steel plate (11) by screws (16); the stirring rod (7) is connected to the motor (6) and can be removed; the stirring rod (7) is provided with blades (17); the steel basin (10) is fixed to the bottom of the box (2); the stirring rod (7) is located inside the steel basin (10) after installation and its height is adjustable; the steel plate (11) is fixed to the side wall of the box (2) by screws (12); the inner wall of the box (2) is provided with a heat-insulating plate (5); the top of the box (2) is provided with a heat-insulating cover plate (3); the top of the heat-insulating cover plate (3) is provided with a heat-insulating cotton layer (1); The inner wall of the wooden barrel (13) with holes is paved with a layer of preservative film (14); the interior of the preservative film (14) is wrapped with soil (15).

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