A simple evaporation system for rapid measurement of hydraulic parameters of unsaturated soils

Abstract

The application provides a simple evaporation system for quickly measuring unsaturated soil hydraulic parameters, comprising a weighing sensor, a sample preparation cylinder outer cylinder, a soil sample, a base plate, a first tension meter, a second tension meter, a third tension meter, a wireless transmission collector, a power transmission module, a power reception module, a transparent organic glass box and an evaporation control system. The application provides a simple evaporation system for quickly measuring unsaturated soil hydraulic parameters, which can accurately determine the initial saturated state of the bottom of the sample by relying on the measurement value of the bottom tension meter, and can reduce the measurement calculation error by comparing the measurement values of the bottom tension meter and the other two height tension meters; the temperature and humidity control system is adopted to accurately and actively control the evaporation rate of the sample surface; the special glue liquid is used to connect between the soil sample and the sample preparation cylinder, and under the strong cementation effect, the soil sample can not be separated from the sample preparation cylinder during evaporation in the hot environment, thereby keeping the uniformity of the overall structure of the soil sample during the whole test process.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of geotechnical engineering test, and particularly relates to a simple evaporation system for quickly measuring hydraulic parameters of unsaturated soil. BACKGROUND

[0002] The accurate determination of the hydraulic parameters of unsaturated soil is an important basis for the seepage calculation and analysis of geotechnical engineering. The hydraulic parameters of unsaturated soil usually include the soil-water characteristic curve and the permeability coefficient curve. Generally, the hydraulic parameters of unsaturated soil are determined by using a pressure plate apparatus to control the matric suction of a unit sample in stages, and then measuring the soil-water characteristic curve of the soil body after the matric suction reaches equilibrium. The unsaturated permeability coefficient of the unit sample is measured by using a permeameter. However, this method usually needs to wait for a relatively long time for matric suction equilibrium, and is time-consuming and laborious. In addition, the soil-water characteristic curve and the unsaturated permeability system of the soil sample need to be measured separately in two devices. In order to shorten the test time, a simple evaporation method has been developed in recent years. The simple evaporation method usually uses a simple evaporation system. Tension gauges and weighing scales and other sensors are installed in the simple evaporation system to measure the matric suction and the change in water content of the soil body in real time. Because the simple evaporation method has a short test time (for example, the evaporation test of clay can be completed in 10 days in general), and the soil-water characteristic curve and the unsaturated permeability coefficient can be obtained simultaneously in the same simple evaporation system, this method has been favored by more and more researchers of unsaturated soil in recent years.

[0003] At present, the existing simple evaporation system usually installs two tension gauges at different heights of the sample, and then places the sample cylinder on a weighing scale for free evaporation. The readings of the weighing scale are recorded periodically during the evaporation process, so as to deduce the change in water content of the sample. Then, the suction value of the sample during the evaporation process is obtained through the tension gauge data. Finally, the soil-water characteristic curve of the sample can be drawn by using the water content value and the suction value of the sample recorded at different times, and the unsaturated permeability coefficient of the sample can be obtained by calculation.

[0004] However, the existing simple evaporation system has four defects: first, when the simple evaporation method is used, it is assumed that the initial state of the bottom of the sample is completely saturated, and the water content (suction) is linearly distributed along the height of the sample, and then the sample starts to evaporate freely after being placed in the simple evaporation system, but the existing simple evaporation system only installs tension meters at two heights of the sample, and can only measure the suction values of the sample at the two heights, and cannot determine the initial saturated state of the bottom of the sample, nor can it determine whether the initial suction values measured by the two tension meters are in a linear relationship with the suction values at the bottom of the sample; second, the existing simple evaporation system cannot actively control the evaporation rate of the sample, if the evaporation rate of the test is not controlled, on the one hand, it will cause the test time to be uncontrollable, on the other hand, it will increase the measurement error of different types of soil samples, because if the same evaporation rate is used for different soil samples, the internal water distribution of the soil sample is easy to crack under the action of thermal gradient, thereby affecting the continuity of the test data and increasing the calculation error; third, the existing simple evaporation system will cause the sample to be separated from the inner wall of the sample preparation cylinder under the action of the thermal environment during the evaporation process of the soil sample, forming a dry shrinkage crack, which will cause a great test error; fourth, the tension meter in the existing simple evaporation system needs to be connected to the power supply outside the weighing scale through a cable, because the cable and the weighing scale cannot be separated, the weighing scale reading will be affected during the evaporation process of the sample, thereby affecting the measurement accuracy of the test, in general, the existing simple evaporation system has problems such as the initial state of the sample cannot be determined, the evaporation rate of the sample cannot be actively controlled, the soil sample and the sample preparation cylinder wall are easy to separate during the evaporation process, and the sensor cable affects the measurement accuracy, which greatly increases the measurement error of the water hydraulic parameters of the unsaturated soil.

[0005] Therefore, it is necessary to provide a simple evaporation system for quickly measuring the water hydraulic parameters of unsaturated soil to solve the above technical problems. SUMMARY

[0006] The simple evaporation system for quickly measuring the water hydraulic parameters of unsaturated soil provided by the present application solves the problems of the existing simple evaporation system, such as the initial state of the sample cannot be determined, the evaporation rate of the sample cannot be actively controlled, the soil sample and the sample preparation cylinder wall are easy to separate during the evaporation process, and the sensor cable affects the measurement accuracy, which greatly increases the measurement error of the water hydraulic parameters of the unsaturated soil.

[0007] To solve the above technical problems, the simple evaporation system for quickly measuring the water hydraulic parameters of unsaturated soil provided by the present application comprises a weighing sensor, a sample preparation cylinder outer cylinder, a soil sample, a bottom plate, a first tension meter, a second tension meter, a third tension meter, a wireless transmission collector, a power supply transmission module, a power supply receiving module, a transparent organic glass box, and an evaporation control system.

[0008] The weighing sensor is fixedly installed at the bottom of the transparent organic glass box, the bottom disc is arranged at the top of the weighing sensor, the sample preparation cylinder outer cylinder is arranged on the bottom disc, the soil sample is arranged in the inside of the sample preparation cylinder outer cylinder, and glue liquid is arranged between the soil sample and the sample preparation cylinder outer cylinder.

[0009] The evaporation control system is arranged at the top of the inside of the transparent organic glass box, the first tension meter is arranged in the middle of the bottom disc, the second tension meter is arranged on one side of the outer surface of the sample preparation cylinder outer cylinder, the third tension meter is arranged on the other side of the outer surface of the sample preparation cylinder outer cylinder, one side of the first tension meter, the second tension meter and the third tension meter is fixedly connected with tension meter cables, the wireless emission collector is arranged on one side of the tension meter cables, one end of the three tension meter cables is fixedly connected with a cable, the power supply receiving module is arranged at one end of the cable, the power supply emission module is arranged on one side of the power supply receiving module, one side of the power supply emission module is fixedly connected with a power supply emission module lead wire, a support is arranged on the surface of the power supply emission module lead wire, and a fixed support is fixedly connected to the bottom of the support.

[0010] The evaporation control system comprises an evaporation control system bottom plate, a supporting metal plate, heat dissipation holes, an evaporation control cavity, a fan, a heater, a humidifier and a temperature and humidity sensor.

[0011] Preferably, a spiral groove is arranged on the surface of the top of the bottom disc, and a water discharge hole is arranged on one side of the surface of the bottom disc.

[0012] Preferably, the supporting metal plate is arranged at the bottom of the evaporation control system bottom plate, the heat dissipation holes are arranged at the bottom of the supporting metal plate, the evaporation control cavity is arranged at the top of the evaporation control system bottom plate, and the fan, the heater, the humidifier and the temperature and humidity sensor are arranged at the top of the inside of the evaporation control cavity, respectively.

[0013] Preferably, the sample preparation cylinder outer cylinder is a hollow cylinder, the bottom of the sample preparation cylinder outer cylinder is provided with external threads for matching and fixedly installing the bottom disc, the inner diameter of the sample preparation cylinder outer cylinder is greater than the outer diameter of the soil sample, the gap distance between the inner wall of the sample preparation cylinder outer cylinder and the soil sample is 2-5mm, and the soil sample is vertically placed in the inside center position of the sample preparation cylinder outer cylinder after being prepared and saturated in the compactor and the saturation cylinder.

[0014] Preferably, the material of the sample preparation cylinder outer cylinder is a metal that does not deform in a hot environment, and the material of stainless steel and aluminum alloy is used, so as to prevent the soil sample from producing dry shrinkage cracks in the evaporation process.

[0015] Preferably, the glue liquid is specially made of epoxy resin material, which can be bonded with the soil sample but not flow into the pores of the soil sample, and the glue liquid can be well bonded with the inner wall of the outer cylinder of the sample preparation cylinder. After the glue liquid is cured, it will be cemented with the soil sample and the outer cylinder of the sample preparation cylinder as a whole. Through the cementation of the glue liquid, the soil sample is prevented from being separated from the side wall to form dry shrinkage cracks in the hot environment, and the measurement and calculation errors caused by the problems of dry shrinkage cracks around the soil sample are solved.

[0016] Preferably, the upper surface of the first tensiometer is flush with the upper surface of the base plate, the bottom surface of the soil sample is located on the spiral groove of the base plate, and the excess water in the soil sample due to saturation can freely drip into the spiral groove of the base plate and be discharged through the water outlet hole. The upper surface of the first tensiometer and the bottom surface of the soil sample are closely attached, so that the initial saturation state of the bottom of the soil sample can be determined by the real-time measurement of the suction value of the first tensiometer. The second tensiometer and the third tensiometer respectively pass through the side wall openings of the outer cylinder of the sample preparation cylinder and abut against the surface of the soil sample. The second tensiometer and the third tensiometer are used to measure the matrix suction at two heights during the evaporation process of the soil sample. The installation positions of the second tensiometer and the third tensiometer on the soil sample are at the / and / positions of the height of the soil sample, respectively. When the measured suction values of the first tensiometer, the second tensiometer and the third tensiometer are linear gradients, it can be regarded as the starting point of the evaporation test. The cables of the first tensiometer, the second tensiometer and the third tensiometer are connected to the wireless transmission collector. The wireless transmission collector is placed and fixed on the weighing sensor. The wireless transmission collector is used to collect the suction data of the first tensiometer, the second tensiometer and the third tensiometer in real time, and transmit the data to the computer software for data storage through the internal wireless transmission module using the Internet of Things ZigBee protocol.

[0017] Preferably, the wireless emission collector is connected to the power supply receiving module through the cable, the power supply emission module is suspended above the power supply receiving module through the fixing of the support and the fixed support, the vertical distance between the power supply receiving module and the power supply emission module is 2-10 mm, the power supply emission module is connected to the external stabilized power supply through the lead wire, the power supply emission module generates electromagnetic induction under the excitation of the external power supply, the coil in the emission module excites to generate current, and then the current is wirelessly transmitted to the power supply receiving module, the power supply receiving module can simultaneously supply power to the wireless emission collector, the first tension meter, the second tension meter and the third tension meter, thereby ensuring that the external power supply can realize real-time non-contact power supply for all power components above the weighing sensor, and the problem of affecting the measurement result caused by wired connection power supply is solved.

[0018] Preferably, the evaporation control system is fixed to the top center position of the transparent organic glass box, the evaporation control system is cylindrical, the outer diameter of the evaporation control system is the same as the outer diameter of the outer cylinder of the sample preparation cylinder, the evaporation control system bottom plate is located at the lower part of the evaporation control cavity, the upper part of the evaporation control cavity is fixed on the transparent organic glass box by screw threads, the evaporation control cavity is a hollow cylinder, the heater and the humidifier are symmetrically installed in the evaporation control cavity, the fan is installed between the heater and the humidifier, the fan controls the air speed and temperature of the air discharged from the evaporation control cavity, the heater generates high temperature in the evaporation control cavity, the humidifier controls the humidity of the air discharged from the evaporation control cavity, knobs are arranged on the fan, the heater and the humidifier, and the knobs are arranged outside the transparent organic glass box, the air speed of the fan, the air temperature in the cavity and the humidity can be arbitrarily adjusted by stepless adjustment knobs, and the hot air generated in the evaporation control cavity can be discharged through the heat dissipation holes and then uniformly diffused to the surface of the soil sample.

[0019] Preferably, the surface of the soil sample is 30-150 mm away from the evaporation control system bottom plate, the temperature and humidity sensor is installed in the evaporation control cavity, the temperature and humidity of the air in the evaporation control cavity can be monitored in real time, the fan, the heater and the humidifier in the evaporation control cavity can be arbitrarily adjusted according to the type of the soil sample used in the simple evaporation test and the test duration requirement, and the required air environment temperature and humidity are achieved under the combined action of the three, so that the evaporation rate of the soil sample is accurately controlled.

[0020] Compared with the related art, the simple evaporation system for quickly measuring the hydraulic parameters of unsaturated soil provided by the application has the following beneficial effects:

[0021] The application provides a simple evaporation system for quickly measuring hydraulic parameters of unsaturated soil, which is characterized by the following: installing tension gauges at the bottom of a sample and two heights, judging the initial saturated state of the bottom of the sample according to the measurement value of the bottom tension gauge, judging the accurate starting time of the simple evaporation test according to the measurement values of the bottom tension gauge and the tension gauges at the other two heights, reducing the measurement and calculation errors, using a special temperature and humidity control system to accurately and actively control the evaporation rate of the sample surface, selecting a suitable evaporation rate according to the characteristics of different types of soil to perform the test, which can ensure the matching of the thermal gradient and the water gradient in the sample soil, avoid the uneven distribution of water caused by the water backflow in the sample, using a special glue liquid to connect the soil sample and the sample preparation cylinder, which can make the soil sample not separate from the sample preparation cylinder under the evaporation of the thermal environment, thereby maintaining the uniformity of the overall structure of the soil sample during the whole test process, avoiding the generation of dry shrinkage cracks, and greatly reducing the test error, and using a non-contact power supply system to separate the sensor cable installed on the sample from the external power supply, avoiding the influence of the cable disturbance on the evaporation process of the sample, thereby reducing the test error. BRIEF DESCRIPTION OF DRAWINGS

[0022] Figure 1 A cross-sectional view of a simple evaporation system for quickly measuring hydraulic parameters of unsaturated soil is provided.

[0023] Figure 2 A bottom plate cross-sectional view is shown. Figure 1

[0024] Figure 3 An evaporation control system schematic diagram is shown. Figure 1

[0025] A bottom plate structure schematic diagram of the evaporation control system is shown. Figure 4 Figure 3 A sample preparation cylinder outer cylinder top view schematic diagram is shown.

[0026] Figure 5 Figure 1

[0027] ​​​​The figure mark: 1, weighing sensor, 2, sample preparation cylinder outer cylinder, 3, soil sample, 4, glue solution, 5, bottom disc, 501, spiral groove, 502, water inlet hole, 6, first tension meter, 7, second tension meter, 8, third tension meter, 9, tension meter cable, 10, wireless transmission collector, 11, cable, 12, power transmission module, 13, power receiving module, 14, support, 15, power transmission module wire, 16, fixed support, 17, transparent organic glass box, 18, evaporation control system, 1801, evaporation control system bottom plate, 1802, support metal plate, 1803, heat dissipation hole, 1804, evaporation control cavity, 1805, fan, 1806, heater, 1807, humidifier, 1808, temperature and humidity sensor. DETAILED DESCRIPTION

[0028] The application will be further described below in conjunction with the drawings and embodiments.

[0029] Please refer to Figure 1 、 Figure 2 、 Figure 3 、 Figure 4 and Figure 5 , wherein, Figure 1 is a cross-sectional view of a simple evaporation system for quickly measuring the hydraulic parameters of unsaturated soil provided by the application; Figure 2 is the bottom disc cross-sectional view shown in Figure 1 ; Figure 3 is the evaporation control system shown in Figure 1 ; Figure 4 is the evaporation control system bottom plate structure shown in Figure 3 ; Figure 5 is the sample preparation cylinder outer cylinder top view shown in Figure 1 . A simple evaporation system for quickly measuring the hydraulic parameters of unsaturated soil, comprising: a weighing sensor 1, a sample preparation cylinder outer cylinder 2, a soil sample 3, a bottom disc 5, a first tension meter 6, a second tension meter 7, a third tension meter 8, a wireless transmission collector 10, a power transmission module 12, a power receiving module 13, a transparent organic glass box 17 and an evaporation control system 18;

[0030] The weighing sensor 1 is fixedly installed at the bottom of the transparent organic glass box 17, the bottom disc 5 is arranged on the top of the weighing sensor 1, the sample preparation cylinder outer cylinder 2 is placed on the bottom disc 5, the soil sample 3 is arranged in the inside of the sample preparation cylinder outer cylinder 2, and the soil sample 3 and the sample preparation cylinder outer cylinder 2 are provided with the glue solution 4;

[0031] The evaporation control system 18 is arranged at the top inside the transparent organic glass box 17, the first tension meter 6 is arranged in the middle of the base plate 5, the second tension meter 7 is arranged on one side of the outer surface of the sample preparation cylinder outer cylinder 2, the third tension meter 8 is arranged on the other side of the outer surface of the sample preparation cylinder outer cylinder 2, one side of the first tension meter 6, the second tension meter 7 and the third tension meter 8 is fixedly connected with tension meter cable 9, wireless transmission collector 10 is arranged on one side of the tension meter cable 9, one end of three tension meter cables 9 is commonly fixedly connected with cable 11, power supply receiving module 13 is arranged at one end of the cable 11, power supply transmission module 12 is arranged on one side of the power supply receiving module 13, one side of the power supply transmission module 12 is fixedly connected with power supply transmission module lead 15, the surface of the power supply transmission module lead 15 is provided with support 14, the bottom of the support 14 is fixedly connected with fixed support 16.

[0032] The evaporation control system 18 includes evaporation control system bottom plate 1801, support metal plate 1802, heat dissipation hole 1803, evaporation control cavity 1804, fan 1805, heater 1806, humidifier 1807 and temperature and humidity sensor 1808.

[0033] The surface of the top of the base plate 5 is provided with a spiral groove 501, and a water inlet hole 502 is formed on one side of the surface of the base plate 5.

[0034] The support metal plate 1802 is arranged at the bottom of the evaporation control system bottom plate 1801, the heat dissipation hole 183 is formed at the bottom of the support metal plate 1802, the evaporation control cavity 1804 is arranged at the top of the evaporation control system bottom plate 1801, and the fan 1805, the heater 1806, the humidifier 1807 and the temperature and humidity sensor 1808 are arranged at the top of the evaporation control cavity 1804 respectively.

[0035] The sample preparation cylinder outer cylinder 2 is a hollow cylinder, the bottom is provided with external threads for matching and fixing with the base plate 5, the inner diameter of the sample preparation cylinder outer cylinder 2 is larger than the outer diameter of the soil sample, the gap distance between the inner wall of the sample preparation cylinder outer cylinder 2 and the soil sample 3 is 2-5mm, and the soil sample 3 is prepared in the compactor and the saturation cylinder, and is placed vertically in the center position of the sample preparation cylinder outer cylinder 2 after saturation.

[0036] The material of the sample preparation cylinder outer cylinder 2 requires metal that does not deform in a hot environment, and the materials of stainless steel and aluminum alloy are used to prevent dry shrinkage cracks on the side wall of the soil sample 3 during evaporation.

[0037] The glue liquid 4 is specially made of epoxy resin material, which can be bonded with the soil sample 3 but not flow into the pores of the soil sample 3, and the glue liquid 4 can be well bonded with the inner wall of the sample making cylinder outer cylinder 2. After the glue liquid 4 is cured, it is integrated with the soil sample 3 and the sample making cylinder outer cylinder 2. Through the cementation of the glue liquid 4, the soil sample 3 is prevented from being separated from the side wall to form a dry shrinkage crack in a hot environment, and the measurement and calculation error caused by the problem of the dry shrinkage crack around the soil sample is solved.

[0038] The upper surface of the first tension meter 6 is flush with the upper surface of the bottom disc 5, the bottom surface of the soil sample 3 is located on the spiral groove 501 of the bottom disc 5, the excess water in the soil sample 3 due to saturation can freely drop into the spiral groove 501 of the bottom disc 5 and be discharged through the water outlet hole 502, the upper surface of the first tension meter 6 and the bottom surface of the soil sample 3 are closely attached, the initial saturation state of the bottom of the soil sample 3 can be determined by the real-time measurement of the suction value of the first tension meter 6, the second tension meter 7 and the third tension meter 8 respectively pass through the side wall openings of the sample making cylinder outer cylinder 2 and abut against the surface of the soil sample 3, the functions of the second tension meter 7 and the third tension meter 8 are to measure the matrix suction at two heights in the evaporation process of the soil sample 3, the installation positions of the second tension meter 7 and the third tension meter 8 on the soil sample 3 are respectively at the positions of 1 / 3 and 2 / 3 of the height of the soil sample 3, when the measured suction values of the first tension meter 6, the second tension meter 7 and the third tension meter 8 are linear gradient, it can be regarded as the starting point of the evaporation test, the cables 9 of the first tension meter 6, the second tension meter 7 and the third tension meter 8 are connected with the wireless transmission collector 10, the wireless transmission collector 10 is placed and fixed on the weighing sensor 1, the function of the wireless transmission collector 10 is to collect the suction data of the first tension meter 6, the second tension meter 7 and the third tension meter 8 in real time, and transmit the data to the computer software through the internal wireless transmission module using the Internet of Things ZigBee protocol for data storage.

[0039] The wireless emission collector 10 is connected with the power supply receiving module 13 through the cable 11, the power supply emission module 12 can be suspended above the power supply receiving module 13 through the fixing of the support 14 and the fixed support 16, the vertical distance between the power supply receiving module 13 and the power supply emission module 12 is 2-10mm, the power supply emission module 12 is connected with an external stabilized power supply through the wire 15, the power supply emission module 12 generates electromagnetic induction under the excitation of the external power supply, and the coil in the emission module excites to generate current, and then the current is wirelessly transmitted to the power supply receiving module 13, the power supply receiving module 13 can simultaneously supply power to the wireless emission collector 10, the first tension meter 6, the second tension meter 7 and the third tension meter 8, so that the external power supply can realize real-time non-contact power supply for all power components on the weighing sensor 1, and the problem of affecting the measurement result caused by wired connection power supply is solved.

[0040] The evaporation control system 18 is installed and fixed at the top center position of the transparent organic glass box 17, the evaporation control system 18 is a cylinder, the outer diameter of the evaporation control system 18 is the same as the outer diameter of the sample preparation cylinder outer cylinder 2, the evaporation control system bottom plate 1801 is located at the lower part of the evaporation control cavity 1804, the upper part of the evaporation control cavity 1804 is fixed on the transparent organic glass box 17 by screw threads, the evaporation control cavity 1804 is a hollow cylinder, the heater 1806 and the humidifier 1807 are symmetrically installed in the evaporation control cavity 1804, the fan 1805 is installed between the heater 1806 and the humidifier 1807, the fan 1805 controls the air speed and temperature of the air discharged from the evaporation control cavity 1804, the heater 1806 generates high temperature in the evaporation control cavity 1804, the humidifier 1807 controls the humidity of the air discharged from the evaporation control cavity 1804, knobs are arranged on the fan 1805, the heater 1806 and the humidifier 1807, and the knobs are arranged outside the transparent organic glass box 17, the air speed, the air temperature in the cavity and the humidity can be arbitrarily adjusted by stepless adjustment knobs, and the hot air generated in the evaporation control cavity 1804 can be discharged through the heat dissipation hole 1803 and then uniformly diffused to the surface of the soil sample 3.

[0041] The surface of the soil sample 3 is 30-150mm away from the evaporation control system bottom plate 1801, the temperature and humidity sensor 1808 is installed in the evaporation control cavity 1804, the temperature and humidity of the air in the evaporation control cavity 1804 can be monitored in real time, the fan 1805, the heater 1806 and the humidifier 1807 in the evaporation control cavity 1804 can be adjusted at will according to the type of the soil sample used in the simple evaporation test and the test time length requirement, and the air environment temperature and humidity required in the test can be achieved under the joint action of the three, so that the evaporation rate of the soil sample 3 can be accurately controlled.

[0042] The working principle of the simple evaporation system for quickly measuring the hydraulic parameters of unsaturated soil provided by the application is as follows:

[0043] In operation, the weighing sensor 1 is used to measure the change of the mass of the soil sample thereon in real time, the gap distance between the inner wall of the sample preparation cylinder outer cylinder 2 and the soil sample 3 is 2-5mm, the soil sample is prepared in the compactor and the saturation cylinder, and is placed vertically in the central position of the inside of the sample preparation cylinder outer cylinder after being saturated, in order to prevent the soil sample 3 from being separated from the side wall to form dry shrinkage cracks during evaporation, after the soil sample 3 is placed in the sample preparation cylinder outer cylinder 2, glue liquid 4 is poured into the gap between the sample preparation cylinder outer cylinder 2 and the soil sample 3, and the glue liquid 4 is bonded with the soil sample 3 but does not flow into the pores of the soil sample 3, and the glue liquid 4 can be well bonded with the inner wall of the sample preparation cylinder outer cylinder 2, after the glue liquid 4 is solidified, the glue liquid 4 is cemented with the soil sample 3 and the sample preparation cylinder outer cylinder 2 as a whole, and through the cementation of the glue liquid 4, the dry shrinkage cracks of the soil sample 3 in the hot environment can be avoided, and the measurement and calculation errors caused by the problems of the dry shrinkage cracks around the soil sample in the existing simple evaporation system are well solved.

[0044] The wireless transmission collector 10 is used to collect the suction data of the first tension meter 6, the second tension meter 7 and the third tension meter 8 in real time, and wirelessly transmit the data to the computer software for data storage through the internal wireless transmission module using the Internet of Things ZigBee protocol, the wireless transmission collector 10 is connected with the power supply receiving module 13 through the cable 11, the power supply transmission module 12 is connected with the external stabilized power supply through the wire 15, the power supply transmission module 12 generates electromagnetic induction under the excitation of the external power supply, generates current by exciting the coil in the transmission module, and then wirelessly transmits to the power supply receiving module 13, the power supply receiving module 13 can simultaneously supply power to the wireless transmission collector 10, the first tension meter 6, the second tension meter 7 and the third tension meter 8, so as to ensure that the external power supply can supply power to all power components on the weighing sensor 1 in real time without contact, and the problem that the cable affects the measurement result caused by the wired connection power supply in the existing simple evaporation system is solved.

[0045] The fan 1805 is used to control the air speed and temperature of the air discharged from the evaporation control cavity 1804, the heater 1806 is used to generate high temperature in the evaporation control cavity 1804, and the humidifier 1807 is used to control the humidity of the air discharged from the evaporation control cavity 1804, and knobs are arranged on the fan 1805, the heater 1806 and the humidifier 1807, the knobs are arranged outside the transparent organic glass box, the air speed, the air temperature and the humidity in the cavity can be adjusted arbitrarily by stepless adjustment of the knobs, the hot air generated in the evaporation control cavity 1804 can be discharged through the heat dissipation holes 1803 and then uniformly diffused to the surface of the soil sample 3, the distance between the surface of the soil sample 3 and the bottom plate 1801 of the evaporation control system is 30-150 mm, the temperature and humidity sensor 1808 is installed in the evaporation control cavity 1804, the temperature and humidity of the air in the evaporation control cavity 1804 can be monitored in real time, according to the type of the soil sample used in the simple evaporation test (for example, clay, silt or sand) and the test duration requirement, the fan 1805, the heater 1806 and the humidifier 1807 in the evaporation control cavity 1804 can be adjusted arbitrarily, and the air environment temperature and humidity required by the test can be achieved under the joint action of the three, so that the evaporation rate of the soil sample 3 can be accurately controlled, and the problem of uneven distribution of water caused by excessive temperature gradient in the soil sample is avoided, and the test error is reduced.

[0046] Compared with the related art, the simple evaporation system for quickly measuring the hydraulic parameters of unsaturated soil has the following beneficial effects:

[0047] The simple evaporation system for quickly measuring the hydraulic parameters of unsaturated soil is provided, the initial saturated state of the sample bottom can be accurately judged by the measurement value of the bottom tension meter, and the accurate starting time of the simple evaporation test can be accurately judged by comparing the measurement values of the bottom tension meter and the other two tension meters at different heights, so that the measurement and calculation errors are reduced; the special temperature and humidity control system is adopted to accurately and actively control the evaporation rate of the sample surface, the appropriate evaporation rate can be selected according to the characteristics of different types of soil bodies to perform the test, so that the matching of the thermal gradient and the water gradient in the soil body of the sample can be ensured, and the uneven distribution of water caused by the backflow of water in the sample is avoided; the special glue liquid is used to connect the soil sample and the sample making cylinder, the soil sample can not be separated from the sample making cylinder under the action of the strong glue, so that the uniformity of the overall structure of the soil sample in the whole test process is maintained, the generation of dry shrinkage cracks is avoided, and the test error is greatly reduced; the contactless power supply system is adopted, the sensor cable installed on the sample is separated from the external power supply, the influence of the cable disturbance on the evaporation process of the sample is avoided, and the test error is reduced.

[0048] The above merely illustrates the embodiments of the present application, and is not intended to limit the patent scope of the present application. Any equivalent structure or equivalent process conversion, or direct or indirect application in other related technical fields, which is made according to the content of the present application, shall be included in the patent protection scope of the present application.

Claims

1. A simple evaporation system for rapid measurement of non-saturated soil hydraulic parameters, characterized in that, The utility model relates to a kind of soil sample preparation device, including: A weighing sensor, a sample preparation cylinder outer cylinder, a soil sample, a base plate, a first tension meter, a second tension meter, a third tension meter, a wireless transmission collector, a power transmission module, a power receiving module, a transparent organic glass box and an evaporation control system are included. The weighing sensor is fixedly installed at the bottom of the transparent organic glass box, the base plate is arranged on the top of the weighing sensor, the sample preparation cylinder outer cylinder is placed on the base plate, the soil sample is arranged inside the sample preparation cylinder outer cylinder, a glue liquid is arranged between the soil sample and the sample preparation cylinder outer cylinder, the glue liquid is made of epoxy resin material, can be bonded with the soil sample but not flow into the pore of the soil sample, and the glue liquid and the inner wall of the sample preparation cylinder outer cylinder are bonded. The evaporation control system is arranged at the top inside the transparent organic glass box, the first tension meter is arranged in the middle of the base plate, the second tension meter is arranged on one side of the outer surface of the sample preparation cylinder outer cylinder, the third tension meter is arranged on the other side of the outer surface of the sample preparation cylinder outer cylinder, one side of the first tension meter, the second tension meter and the third tension meter is fixedly connected with tension meter cable, the wireless transmission collector is arranged on one side of the tension meter cable, one end of the three tension meter cables is fixedly connected with a cable, the power receiving module is arranged at one end of the cable, the power transmission module is arranged on one side of the power receiving module, one side of the power transmission module is fixedly connected with power transmission module lead wire, a support is arranged on the surface of the power transmission module lead wire, and a fixed support is fixedly connected to the bottom of the support. The evaporation control system includes an evaporation control system bottom plate, a support metal plate, a heat dissipation hole, an evaporation control cavity, a fan, a heater, a humidifier and a temperature and humidity sensor.

2. The simple evaporation system for quickly measuring the hydraulic parameters of unsaturated soil according to claim 1, characterized in that, A spiral groove is arranged on the surface of the top of the base plate, and a water inlet hole is formed on one side of the surface of the base plate.

3. The simple evaporation system for quickly measuring the hydraulic parameters of unsaturated soil according to claim 1, characterized in that, The support metal plate is arranged at the bottom of the evaporation control system bottom plate, the heat dissipation hole is formed at the bottom of the support metal plate, the evaporation control cavity is arranged at the top of the evaporation control system bottom plate, and the fan, the heater, the humidifier and the temperature and humidity sensor are respectively arranged at the top inside the evaporation control cavity.

4. The simple evaporation system for quickly measuring the hydraulic parameters of unsaturated soil according to claim 1, characterized in that, The sample preparation cylinder outer cylinder is a hollow cylinder, and an external thread is arranged at the bottom for matching and fixing with the base plate.

5. The simple evaporation system for quickly measuring the hydraulic parameters of unsaturated soils according to claim 1, characterized in that, The material of the sample preparation cylinder outer cylinder requires a metal that does not deform in a hot environment to prevent dry shrinkage cracks on the side wall of the soil sample during evaporation.

6. The simple evaporation system for quickly measuring the hydraulic parameters of unsaturated soil according to claim 2, characterized in that, The upper surface of the first tension meter is flush with the upper surface of the bottom disc, the bottom surface of the soil sample is located on the spiral groove of the bottom disc, the excess water in the soil sample due to saturation can freely drip into the spiral groove of the bottom disc and be discharged through the water outlet hole, the upper surface of the first tension meter and the bottom surface of the soil sample are tightly attached, the initial saturation state of the bottom of the soil sample is determined by the real-time measurement of the suction value of the first tension meter, the second tension meter and the third tension meter respectively pass through the side wall openings of the outer cylinder of the sample preparation cylinder and abut against the surface of the soil sample, the second tension meter and the third tension meter function to measure the matrix suction at two heights during the evaporation process of the soil sample, the installation positions of the second tension meter and the third tension meter on the soil sample are respectively at 1 / 3 and 2 / 3 of the height of the soil sample, when the measured suction values of the first tension meter, the second tension meter and the third tension meter are linear gradient, it is the starting point of the evaporation test, the cables of the first tension meter, the second tension meter and the third tension meter are connected with the wireless transmission collector, the wireless transmission collector is placed and fixed on the weighing sensor, the wireless transmission collector functions to collect the suction data of the first tension meter, the second tension meter and the third tension meter in real time, and wirelessly transmit the data to the computer software through the internal wireless transmission module using the Internet of Things ZigBee protocol for data storage.

7. The simple evaporation system for quickly measuring the hydraulic parameters of unsaturated soils according to claim 1, characterized in that, The wireless transmission collector is connected with the power supply receiving module through a cable, the power supply transmission module is suspended directly above the power supply receiving module through the support and the fixed support, the vertical distance between the power supply receiving module and the power supply transmission module is 2-10 mm, the power supply transmission module is connected with an external stabilized power supply through the lead wire, the power supply transmission module generates electromagnetic induction under the excitation of external power supply, generates current by exciting the coil in the transmission module, and then wirelessly transmits to the power supply receiving module, the power supply receiving module simultaneously supplies power to the wireless transmission collector, the first tension meter, the second tension meter and the third tension meter.

8. The simple evaporation system for quickly measuring the hydraulic parameters of unsaturated soils according to claim 1, characterized in that, The evaporation control system is fixedly installed at the top center of the transparent organic glass box, the evaporation control system is cylindrical, the outer diameter of the evaporation control system is the same as the outer diameter of the outer cylinder of the sample preparation cylinder, the bottom plate of the evaporation control system is located at the lower part of the evaporation control cavity, the upper part of the evaporation control cavity is fixed on the transparent organic glass box by screw threads, the evaporation control cavity is a hollow cylinder, the heater and the humidifier are symmetrically installed in the interior of the evaporation control cavity, the fan is installed between the heater and the humidifier, the fan controls the air speed and temperature of the air discharged from the evaporation control cavity, the heater generates high temperature in the evaporation control cavity, the humidifier controls the humidity of the air discharged from the evaporation control cavity, knobs are arranged on the fan, the heater and the humidifier, the knobs are arranged outside the transparent organic glass box, the air speed of the fan, the air temperature in the cavity and the humidity are adjusted by stepless adjustment knobs, the hot air generated in the evaporation control cavity is discharged through the heat dissipation holes and then uniformly diffused to the surface of the soil sample.

9. The simple evaporation system for quickly measuring the hydraulic parameters of unsaturated soils according to claim 1, characterized in that, The surface of the soil sample is 30-150mm away from the bottom plate of the evaporation control system, the temperature and humidity sensor is installed in the evaporation control cavity, the temperature and humidity of the air in the evaporation control cavity are monitored in real time, and the fan, the heater and the humidifier in the evaporation control cavity are adjusted according to the type of the soil sample used in the simple evaporation test and the test duration requirement.

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