阅读说明：本技术 一种温度梯度作用下土壤蒸发水分场变化测试装置及方法 (Device and method for testing field change of soil evaporation moisture under temperature gradient effect ) 是由 张宇 罗扬 王铁行 何江涛 于 2020-06-23 设计创作，主要内容包括：本发明公开了一种温度梯度作用下土壤蒸发水分场变化测试装置及方法,包括蒸发装置,土壤蒸发水分测试系统和土壤温湿度水分测试系统；蒸发装置设在土壤蒸发水分测试系统上,并连接土壤温湿度水分测试系统；通过控制恒温水浴箱温度,对蒸发装置中土体底部提供初始蒸发温度；通过土壤温湿度水分测试系统获取蒸发装置中土体的水分蒸发信息。本发明尽可能的模拟实际工程中土体不同位置处受到不同温度的作用进行蒸发,并且在尽量不扰动土体的初始结构状态的同时进行蒸发式过程中水分场变化过程的测量,最终揭示不同温度梯度作用下土壤蒸发水分场的变化规律。并且入渗装置不易产生变形,材料环保经济。(The invention discloses a device and a method for testing the field change of soil evaporation moisture under the action of a temperature gradient, wherein the device comprises an evaporation device, a soil evaporation moisture testing system and a soil temperature, humidity and moisture testing system; the evaporation device is arranged on the soil evaporation moisture test system and is connected with the soil temperature, humidity and moisture test system; providing an initial evaporation temperature for the bottom of a soil body in the evaporation device by controlling the temperature of the constant-temperature water bath box; and acquiring water evaporation information of a soil body in the evaporation device through the soil temperature, humidity and water test system. The invention simulates the effect of different temperatures on different positions of the soil body in the actual engineering as much as possible to evaporate, and measures the change process of the moisture field in the evaporation process while not disturbing the initial structure state of the soil body as much as possible, thereby finally revealing the change rule of the moisture field evaporated by the soil under the action of different temperature gradients. And the infiltration device is not easy to deform, and the material is environment-friendly and economical.)

1. A field change testing device for soil evaporation moisture under the action of a temperature gradient is characterized by comprising an evaporation device, a set of soil evaporation moisture testing system and a set of soil temperature, humidity and moisture testing system; the evaporation device is arranged on the soil evaporation moisture test system and is connected with the soil temperature, humidity and moisture test system;

the evaporation device comprises an insulation heat insulation U-shaped groove (15) and an insulation heat insulation plate (8), and a soil body (16) and a temperature and moisture sensor (9) connected to a soil evaporation moisture test system are arranged in the evaporation device;

the soil evaporation moisture test system comprises a constant-temperature water bath box (1) and an aluminum alloy metal box (6) which are communicated with each other, wherein an evaporation device is fixed on the aluminum alloy metal box (6);

providing an initial evaporation temperature for the bottom of a soil body (16) in the evaporation device by controlling the temperature of the constant-temperature water bath box (1); the water evaporation information of a soil body (16) in the evaporation device is obtained through a soil temperature, humidity and water test system.

2. The device for testing the field change of the soil evaporated moisture under the action of the temperature gradient according to claim 1, wherein the insulating and heat-insulating U-shaped groove (15) is in a frame shape formed by three panels, and the insulating and heat-insulating plate (8) is inserted into the slot (10) in front of the insulating and heat-insulating U-shaped groove (15).

3. The device for testing the change of the soil evaporation moisture field under the action of the temperature gradient as claimed in claim 2, wherein the insulation and heat insulation U-shaped groove (15) is fixed with an anti-deformation confining device (11) at the upper and lower parts.

4. The device for testing the field change of the soil evaporated moisture under the action of the temperature gradient according to claim 1, wherein the insulating and heat-insulating plate (8) is provided with an opening into which the temperature and moisture sensor (9) can be inserted, and the opening is filled and sealed by using heat-insulating materials.

5. The field change testing device of the soil evaporated moisture under the action of the temperature gradient according to claim 1, characterized in that the inner walls of the insulating and heat-insulating U-shaped groove (15) and the insulating and heat-insulating plate (8) are coated with waterproof materials and provided with waterproof films; the peripheries of the insulating and heat-insulating U-shaped groove (15) and the insulating and heat-insulating plate (8) are wrapped with heat-insulating materials.

6. The soil evaporation moisture field change testing device under the action of the temperature gradient as claimed in claim 1, characterized in that the constant temperature water bath tank (1) and the aluminum alloy metal tank (6) in the soil evaporation moisture testing system are communicated with the self-pumping water pump (2) through a water conduit (3), and an aluminum alloy fixing barrel (5) for fixing the evaporation device is arranged on the aluminum alloy metal tank (6).

7. The device for testing the change of the soil evaporation moisture field under the action of the temperature gradient as claimed in claim 5, wherein the inner wall of the aluminum alloy fixing barrel (5) is provided with a fixing barrel outer convex groove (14), and the insulating and heat-insulating U-shaped groove (15) and the insulating and heat-insulating plate (8) are provided with inner grooves (17) matched with the fixing barrel outer convex groove (14); the bottom surface of the soil body (16) is contacted with the top surface of the aluminum alloy metal box (6).

8. The device for testing the field change of the soil evaporated moisture under the action of the temperature gradient according to claim 5, wherein the soil temperature, humidity and moisture testing system comprises a temperature and moisture acquisition analyzer (12) and a computer (13) which are connected with the temperature and moisture sensor (9).

9. A method for testing field change of soil evaporation moisture under the action of temperature gradient of the device according to any one of claims 1-8, which comprises the following steps:

1) placing a soil sample (16) with the outer surface coated with vaseline in a U-shaped groove (15), inserting an insulating thermal baffle (8) along an inner groove (10) of the inner wall of the U-shaped groove, and fixing an evaporation device by adopting a deformation prevention confining device (11);

2) the fixed evaporation plant is arranged on an aluminum alloy fixed barrel (5), and the bottom surface of the soil body (16) is contacted with the top surface of an aluminum alloy metal box (6);

3) the temperature and moisture sensor (9) is inserted into the insulating heat insulation plate (8) and is contacted with the soil body (16);

4) controlling the constant temperature of the constant temperature water bath box (1), and starting the self-pumping water pump (2) to heat the soil body (16) at the bottom of the evaporation device; the temperature and moisture acquisition analyzer (12) is used for reading the test data of the temperature, the humidity and the moisture of the soil, and the computer (13) is used for calculating the volume water content of the tested soil body so as to finish the field change test of the evaporated moisture of the soil under the action of temperature gradient.

10. The method as claimed in claim 9, wherein the method comprises calculating the volumetric water content of the soil mass, the digital output value V and the volumetric water content w of the soil mass after drying_vThe parameters are regressed by a quadratic equation model with the following regression formula:

w_v＝A+B·V+C·V²

wherein: w is a_vA, B, C are regression parameters respectively for the volume water content of the soil, and V is the digital output value of the moisture recorder;

calculating the temperature output value T of the soil body to be measured_vAnd (3) regressing parameters by using a unitary quadratic equation model with the actual soil temperature value T, wherein the regression formula is as follows:

wherein: t is the soil temperature measured by the thermometer, T_vC, D, E are regression parameters respectively for the temperature measured by the temperature and moisture sensor;

the conversion formula of the volume content and the mass water content in the water field is as follows:

wherein: w is a_dThe mass water content of the soil body; rho_dThe dry density of the sample of loess body.

Technical Field

The invention belongs to the technical field of rock-soil model test equipment, and discloses a device and a method for testing the field change of soil evaporation moisture under the action of a temperature gradient.

Background

Evaporation is an important factor influencing soil water balance, water consumption caused by evaporation is very considerable, and the evaporation is not only related to soil water retention, loss and soil salinization, but also has profound influence on roadbed strength, deformation, seepage, plant selection, configuration and the like in geotechnical engineering, and causes the problems of slope stability, seasonal expansion and contraction deformation of the ground and roadbed collapse, so that evaporation plays an important role in water balance and energy balance and is an important boundary in soil body water field calculation. However, when the evaporation strength is determined, because of the particularity of loess, the difference between the evaporation and the change of the water field along with the time during the evaporation of loess, the change of the water field in the loess evaporation process is difficult to grasp, and a scheme for determining the evaporation problem in the loess area by detecting the change of the water field in the loess evaporation process and testing the change of the water field in the soil evaporation at different temperatures is provided.

At present, the evaporation is mostly simulated by unsaturated loess shallow evaporation on earth surface, and the temperature change in the earth surface evaporation process can cause the moisture migration in soil, thereby changing the properties of soil body. However, the research on the deep evaporation of soil bodies at different temperatures is less at present, but geothermal wells, ground source heat pumps, combustible ice exploitation and the like in the actual engineering all relate to the problem of moisture evaporation in deep soil, and the development of the device and the method for testing the field change of the moisture evaporated from the soil under the action of different temperature gradients has important significance on the stable research on the actual engineering in the later period.

The method for testing the change process of the water field during evaporation at present is to open a designed evaporation model device at each test time node in the evaporation process, dig holes on corresponding positions on a soil body, dig out the soil, test the water content by adopting a microwave oven drying method, fill the hollowed parts completely, close the evaporation device and continue the experiment. The method has the defects that the soil is excavated and the soil is disturbed to a certain extent before and after the excavation, the structural property of the tested soil cannot be completely guaranteed not to be changed, the water content of the compensated soil cannot be accurately determined, and the change rule of the evaporated moisture field under different temperatures is influenced. And the method for testing the water content by manually digging soil has large test amount and is difficult to finish in a short time.

Disclosure of Invention

In order to solve the defects in the prior art, the invention aims to provide a device and a method for testing the change of a soil evaporation moisture field under the action of temperature gradients. The device is convenient to disassemble, the infiltration device is not easy to deform, and the used materials are environment-friendly and economical.

In order to achieve the above object, the present invention is achieved by the following technical means.

A field change testing device for soil evaporation moisture under the action of temperature gradient comprises an evaporation device, a set of soil evaporation moisture testing system and a set of soil temperature, humidity and moisture testing system; the evaporation device is arranged on the soil evaporation moisture test system and is connected with the soil temperature, humidity and moisture test system;

the evaporation device comprises an insulation heat insulation U-shaped groove and an insulation heat insulation plate, and a soil body and a temperature and moisture sensor connected to a soil evaporation moisture test system are arranged in the evaporation device;

the soil evaporation moisture test system comprises a constant-temperature water bath box and an aluminum alloy metal box which are mutually communicated, wherein an evaporation device is fixed on the aluminum alloy metal box;

providing an initial evaporation temperature for the bottom of a soil body in the evaporation device by controlling the temperature of the constant-temperature water bath box; and acquiring water evaporation information of a soil body in the evaporation device through the soil temperature, humidity and water test system.

With respect to the above technical solution, a further preferred solution of the present invention is further:

preferably, the insulation and heat insulation U-shaped groove is in a surrounding frame shape formed by three panels, and the insulation and heat insulation board is inserted into the slot in front of the insulation and heat insulation U-shaped groove.

Preferably, the insulation and heat insulation U-shaped groove is fixed with an anti-deformation fastening device at the upper and lower parts.

Preferably, the insulating and heat insulating plate is provided with an opening into which the temperature and moisture sensor can be inserted, and the opening is filled and sealed by adopting a heat insulating material.

Preferably, the insulating and heat-insulating U-shaped groove and the inner wall of the insulating and heat-insulating plate are coated with waterproof materials and provided with waterproof films; the insulating heat insulation U-shaped groove and the periphery of the insulating heat insulation plate are wrapped with heat insulation materials.

Preferably, the constant-temperature water bath box and the aluminum alloy metal box in the soil evaporation moisture test system are communicated with the self-pumping water pump through a water guide pipe, and an aluminum alloy fixing barrel for fixing the evaporation device is arranged on the aluminum alloy metal box.

Preferably, the inner wall of the aluminum alloy fixing barrel is provided with a fixing barrel outer convex groove, and the insulating and heat-insulating U-shaped groove and the insulating and heat-insulating plate are provided with inner grooves matched with the fixing barrel outer convex groove; the bottom surface of the soil body is contacted with the top surface of the aluminum alloy metal box.

Preferably, the soil temperature, humidity and moisture test system comprises a temperature and moisture acquisition analyzer and a computer which are connected with the temperature and moisture sensor.

The invention further provides a method for testing the change of the soil evaporation moisture field under the action of the temperature gradient of the device, which comprises the following steps:

1) placing the soil sample coated with vaseline on the outer surface in a U-shaped groove, inserting an insulating thermal baffle along an inner groove of the inner wall of the U-shaped groove, and fixing an evaporation device by adopting a deformation-preventing confining device;

2) installing the fixed evaporation plant on an aluminum alloy fixed barrel, wherein the bottom surface of a soil body is in contact with the top surface of an aluminum alloy metal box;

3) the temperature and moisture sensor is inserted into the insulating heat insulation plate and contacts with the soil body;

4) controlling the constant temperature of the constant temperature water bath box, and starting the self-pumping water pump to heat the soil body at the bottom of the evaporation device; and reading the test data of the temperature, the humidity and the moisture of the soil by a temperature and moisture acquisition analyzer, and calculating the volume water content of the tested soil by a computer to finish the field change test of the soil evaporated moisture under the action of temperature gradient.

The invention adopts an indoor simulation test method to better simulate the test of the change of the evaporation water field under the action of temperature gradient, solves the problems of the change of the water field along with time and the like when loess body evaporates under different temperatures, can actually measure the distribution state of the water content of each point in the soil evaporation water field under different temperatures while not disturbing the initial structure state of the soil body as much as possible, determines the evaporation strength of the soil under different temperatures, further analyzes to obtain the real-time change rule of the evaporation water field under different temperatures, has important significance for theoretical research on the analysis of the change of the water content, such as the generation of the change of the soil body structure and the property, and the like, and provides reference for actual projects such as slope stability, seasonal expansion and contraction deformation of the ground, subgrade collapse and the like. The device is comparatively convenient to dismantle, and the infiltration device is difficult for producing the deformation, and uses the material environmental protection economy.

Drawings

The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this application, illustrate embodiment(s) of the invention and together with the description serve to explain the principles of the invention:

FIG. 1 is a schematic structural diagram of a soil evaporation moisture field change testing device under the action of a temperature gradient according to the present invention;

fig. 2 is a schematic connection diagram of the deformation-preventing fastening device provided in the present invention.

In the figure: 1-constant temperature water bath; 2-self-pumping water pump; 3-a water conduit; 4-water inlet pipe; 5-aluminum alloy fixing barrel; 6-aluminum alloy heating box; 7-a water outlet pipe; 8-insulating and heat insulating board; 9-temperature moisture sensor; 10-slot; 11-deformation prevention fastening device; 12-temperature moisture collector; 13-a computer; 14-fixed barrel outer convex groove; 15-insulating and heat-insulating U-shaped groove; 16-soil body; 17-an inner groove; 18-a fastening screw; 19-a fastening nut; 20-a gasket; and 21-drilling angle steel.

Detailed Description

The invention will be described in detail with reference to the drawings and specific embodiments, which are illustrative of the invention and are not to be construed as limiting the invention.

Referring to fig. 1, the invention provides 1. a soil evaporation moisture field change testing device under the action of temperature gradient, which comprises an evaporation device, a soil evaporation moisture testing system and a soil temperature, humidity and moisture testing system; the evaporation device is arranged on the soil evaporation moisture test system and is connected with the soil temperature, humidity and moisture test system;

the evaporation device comprises an insulation and heat insulation U-shaped groove 14 and an insulation and heat insulation plate 8, and a soil body 16 and a temperature and moisture sensor 9 connected to a soil evaporation moisture test system are arranged in the evaporation device. The soil evaporation moisture test system comprises a constant-temperature water bath box 1 and an aluminum alloy metal box 6 which are mutually communicated, and an evaporation device is fixed on the aluminum alloy metal box 6; by controlling the temperature of the constant-temperature water bath tank 1, the self-pumping water pump 2 is adopted to pump water in the constant-temperature water bath tank 1 to provide an initial evaporation temperature for the aluminum alloy metal tank 6, so that the initial evaporation temperature is provided for the bottom of a soil body 16 in the evaporation device body; and acquiring the water evaporation information of the soil body 16 in the evaporation device through a soil temperature, humidity and water test system.

The insulating and heat-insulating U-shaped groove 15 is in a surrounding frame shape formed by three panels, and the insulating and heat-insulating plate 8 is inserted into a slot in front of the insulating and heat-insulating U-shaped groove 15. And inner grooves 17 are formed on the outer wall of the insulating and heat-insulating plate 8 and the outer three surfaces of the insulating and heat-insulating U-shaped groove 15. An opening which can be inserted into the temperature and moisture sensor 9 is arranged on the insulated heat insulation board 8, and the opening is filled and sealed by adopting heat insulation materials. After a probe of the temperature and moisture sensor 9 is inserted into the soil body 16, the probe can be fixed on the insulating and heat-insulating plate 8, and the insulating and heat-insulating plate 8 is inserted along the slot 10 to cover the soil sample 16.

As shown in fig. 2, and the deformation-preventing fastening device 11 is fixed on the upper and lower sides of the insulating and heat-insulating U-shaped groove 15. After the evaporation device is wrapped with heat insulation materials, fastening bolts 18 penetrate through the deformation-preventing fastening device 11 formed by the upper gasket 20 of the drilling angle steel 21 to fix the evaporation device. Wherein, the inner walls of the insulating and heat-insulating U-shaped groove 15 and the insulating and heat-insulating plate 8 are coated with waterproof materials and are provided with waterproof films; the peripheries of the insulating and heat-insulating U-shaped groove 15 and the insulating and heat-insulating plate 8 are wrapped with heat-insulating materials.

Wherein, constant temperature water bath 1 and aluminum alloy metal case 6 pass through aqueduct 3 and from the intercommunication of drawing formula water pump 2 among the soil evaporation moisture test system, from drawing formula water pump 2 and constant temperature water bath 1 and aluminum alloy metal case oral siphon 4 within a definite time through rubber aqueduct 3 intercommunication, aluminum alloy metal case outlet pipe 7 and constant temperature water bath 1 pass through rubber aqueduct 3 intercommunication. An aluminum alloy fixing barrel 5 for fixing the evaporation device is arranged on the aluminum alloy metal box 6. The inner wall of the aluminum alloy fixing barrel 5 is provided with a fixing barrel outer convex groove 14, the insulating heat insulation U-shaped groove 15 and the inner groove 17 of the insulating heat insulation plate 8 are matched with the fixing barrel outer convex groove 14, the inner grooves 17 on the periphery of the evaporation device and the outer convex groove 14 of the aluminum alloy fixing barrel 5 are mutually complemented and fixed, and the bottom surface of a soil body 16 is contacted with the top surface of the aluminum alloy metal box 6.

The soil temperature, humidity and moisture test system comprises a temperature and moisture acquisition analyzer 12 and a computer 13 which are connected with the temperature and moisture sensor 9. The evaporation device body is placed in an insulation U-shaped groove 15 by a soil sample 16, an insulation board 9 is inserted into the front surface of the evaporation device body, the periphery of the evaporation device body is wrapped by heat insulation materials, the evaporation device body is fixed by an anti-deformation confining device 11 and is placed in an aluminum alloy fixing barrel 5, and the bottom of a soil body 16 in the evaporation device body is contacted with the top surface of an aluminum alloy metal box 6. The other end of the temperature and moisture sensor 9 is connected with the temperature and moisture collector 12 after the probe end is inserted into the soil sample 16, and the computer 13 is connected with the data analysis analyzer 12. By controlling the temperature in the constant temperature water bath tank 1, the self-pumping water pump 2 is adopted to pump the water in the constant temperature water bath tank 1 to provide the initial evaporation temperature for the aluminum alloy metal tank 6. So as to provide initial evaporation temperature for the bottom of the soil body 16 in the evaporation device body.

The method for testing the change of the soil evaporation moisture field under the action of the temperature gradient by using the device comprises the following steps:

1) preparing a soil sample test block with a certain water content according to the requirements of soil engineering tests, and coating vaseline on the outer surface for later use.

2) A soil sample 16 is placed in a vertical insulating U-shaped groove 15, an insulating heat baffle 8 is inserted and covered along an inner wall slot 10 of the U-shaped groove, and an anti-deformation confining device 11 is adopted to be fixed on the upper part and the middle lower part of an evaporation device.

3) The fixed evaporation plant is arranged by aligning with the concave-convex clamping grooves 17 and 14, and the bottom surface of the soil body 16 is contacted with the top surface of the aluminum alloy metal box 6.

4) The temperature and moisture sensor 9 is inserted into the opening on the insulated heat-insulating plate 8 and fixed on the insulated heat-insulating plate; the other end of the temperature and moisture sensor 9 is connected with a temperature and moisture acquisition instrument 12, and a computer 13 is connected with the temperature and moisture acquisition instrument 12.

5) And when the temperature of the constant-temperature water bath box 1 is stabilized at a constant temperature, the self-pumping water pump 2 is started, and the soil body 16 at the bottom of the evaporation device is heated at a constant temperature through the communicating vessel. And (4) testing and collecting the temperature and the moisture content in real time after the self-pumping water pump 2 is started.

6) After the test is finished, the constant temperature water bath tank 1 and the self-pumping water pump 2 are closed, and then the temperature and moisture sensor 9 is pulled out to clean the probe. After the water flow stops, the evaporating device body, the rubber water guide pipe 3 connected between the self-pumping water pump 2 and the constant temperature water bath tank 1 and the water inlet pipe 4, and the rubber water guide pipe 3 between the water outlet pipe 7 and the constant temperature water bath tank 1 are sequentially taken out, and the evaporating device body is disassembled for standby after cleaning.

The invention can actually measure the distribution state of the water content of each point in the soil evaporation water field under different temperature conditions, determine the evaporation intensity of the soil under different temperatures, further analyze to obtain the real-time change of the water content when evaporating under different temperatures, obtain the dynamic change rule of the mass water content field along with the time change when evaporating in the infiltration process through the water content correction and conversion, further have important significance to the theoretical research of the change of the analyzed water content on the initiation of the change of the soil body structure and the property, and the like, and provide reference for the actual projects of slope stability, seasonal expansion and shrinkage deformation of the ground, subgrade collapse and the like. The device is comparatively convenient to dismantle, and the infiltration device is difficult for producing the deformation, and uses the material environmental protection economy.

Firstly, a computer or an RTU (remote terminal unit) is connected with a temperature and moisture sensor to measure tested soil samples with different temperatures and different moisture content levels (the temperature difference is greater than 5 ℃ and the moisture content difference is greater than 4%), a thermometer is used for testing the actual temperature inside the soil at the moment, corresponding temperature and moisture content output values are recorded, meanwhile, 15-30 g of the soil samples are taken and sent to a laboratory for drying at 105 ℃ for 24 hours, and the volume moisture content of the soil is calculated. The recorded water content digital output value (V) and the soil volume water content (w) measured by drying_v) Using a quadratic equation of a single elementThe regression formula is as follows:

w_v＝A+B·V+C·V²

wherein: w is a_vThe soil volume water content is shown as A, B, C as a regression parameter, and V is the digital output value of the moisture recorder.

For recorded temperature output value (T)_v) And the actual temperature value (T) of the soil body measured by the thermometer adopts a unitary quadratic equation model to regress parameters, and the regression formula is as follows:

wherein: t is the soil temperature measured by the thermometer, T_vThe temperature measured by the temperature and moisture sensor is C, D, E regression parameters.

The conversion formula of the volume content and the mass water content in the water field is as follows:

wherein: w is a_dThe mass water content of the soil body; rho_dDry density of the loess body sample.

The invention can realize evaporation and real-time measurement of temperature and water content in the evaporation process, and quantizes the influence of different temperatures on a soil evaporation moisture field while not disturbing the initial structure state of the soil body as much as possible. And the problems of water content error and the like caused by diffusion of water into the mold groove due to uneven heating temperature, uncontrollable temperature and the like of the electric heating plate resistance wire heating device can be avoided. The model device is convenient to mount and dismount, adopts heat-preserving and heat-insulating recyclable materials, and is not easy to deform due to uneven temperature and moisture.

The present invention is not limited to the above-mentioned examples, and based on the technical solutions disclosed in the present invention, those skilled in the art can make some substitutions and modifications to some technical features without creative efforts according to the disclosed technical contents, and these substitutions and modifications are all within the protection scope of the present invention.