Portable undisturbed soil foundation physical property rapid determination device

Abstract

A portable undisturbed soil foundation physical property rapid determination device comprises a microwave heating device, a detection box body and a control panel, a furnace door is hinged to the top of the detection box body, an infrared temperature detector is arranged on the inner surface of the furnace door, a weighing table is arranged at the bottom of the detection box body, and the control panel is arranged on the detection box body. The microwave heating device, the infrared temperature measuring device and the weighing table are all electrically connected with the controller, and the controller is electrically connected with the control panel. Compared with a traditional device for detecting the soil basic physical property, the device can detect various soil basic characteristics through one device, the problem that detection devices are tedious and diverse is solved, and the device is simple in structure, low in cost, close to a common household microwave oven in size and weight, convenient to carry, convenient to use in the outdoor severe environment and suitable for popularization and application. The method is suitable for the use condition of an engineering field and can ensure that an accurate detection result is provided.

Description

Technical Field

[0001] The present invention belongs to the technical field of microwave devices and instruments, and in particular relates to a portable rapid determination device for original soil foundation physical properties, which can rapidly determine soil water content, void ratio, wet density and dry density based on microwave heating. Background Art

[0002] In the field of infrastructure construction, various basic physical properties of soil have an important impact on the stability and performance of the project, and are factors that must be considered during the design, construction and maintenance of infrastructure. Excessive soil moisture content will lead to a decrease in the strength of the soil. Especially for clay soil, the increase in moisture content will reduce its shear strength, thereby affecting the stability of the building foundation and increasing the risk of settlement and landslides. The moisture content of the soil also directly affects the bearing capacity of the foundation. Saturated soil has a low bearing capacity and is prone to settlement and uneven settlement, which has an adverse effect on the safety of the superstructure. Too large a soil porosity ratio will cause the soil to be more easily compressed and deformed when bearing loads, resulting in a lower soil bearing capacity. The dry density and wet density of the soil also reflect the bearing capacity of the soil to a certain extent. The soil with a high dry density has a tighter structure and a higher bearing capacity. Therefore, reasonable detection and control of the basic physical properties of the soil can effectively improve the stability and durability of the building.

[0003] At present, there are many commonly used methods for determining soil moisture content, including drying method, resistance method, tensiometer method and infrared spectroscopy, etc., through which soil moisture content can be determined. The principle of the drying method is to determine the mass difference before and after the soil is dried, that is, the moisture content in the soil. This method is suitable for laboratory measurement, and it takes a long time and is not suitable for rapid on-site detection. The resistance value of the soil is detected by a resistance sensor. The lower the resistance value, the higher the soil moisture content. Although this method is suitable for rapid on-site measurement, its accuracy is not high and is greatly affected by soil type and salt. Moreover, this method can only measure the volumetric moisture content and cannot accurately obtain the absolute moisture content in the soil. The tensiometer method measures the adsorption force of soil moisture and then calculates the moisture content of the soil, but the installation and maintenance are complicated and easily affected by the external environment. In addition, the tensiometer method requires the matrix suction of the soil to correspond to the moisture content, and requires additional experiments such as water retention experiments to measure the SWCC curve. The absorption characteristics of water in the soil are analyzed by infrared spectroscopy, so as to infer the soil water content. Infrared spectroscopy can quickly determine the soil water content, but the equipment required is very expensive and has requirements on the surrounding light, which is easily affected and is not suitable for on-site determination of soil water content. The methods for measuring soil porosity are usually direct measurement, density method, image analysis method, etc. The direct measurement method calculates the porosity by measuring the total volume, solid volume and pore volume of the soil sample. This method is complicated and time-consuming to operate, and it is difficult to ensure accurate volume measurement. The density method usually has large measurement errors and is not suitable for heterogeneous soils, while the image analysis method has high requirements for the cost of experimental equipment, and it is difficult to provide experimental conditions during the construction stage. In addition, the scope of application of this method is limited. For tiny pores or dense soils, the pores are difficult to directly identify and measure through images. In summary, the existing methods for determining the basic physical properties of soil cannot meet the detection needs of all fields, especially construction sites. Therefore, a device that can be easily carried and suitable for the rapid determination of the basic physical properties of soil on the construction site is needed to quickly determine the required basic physical properties of soil under the premise of ensuring the measurement accuracy, to ensure the construction and production efficiency, and to improve the long-term stability of the building. Summary of the invention

[0004] The purpose of the present invention is to provide a portable rapid determination device for the physical properties of undisturbed soil foundations, so as to address the problems that existing determination devices and methods are inconvenient to carry, the equipment is expensive, and the existing determination methods are time-consuming, so as to ensure the production efficiency of the construction site and improve the stability and durability of the building structure.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions:

[0006] A portable rapid determination device for physical properties of undisturbed soil foundation comprises a microwave heating device, a detection box and a control panel, wherein the top of the detection box is hinged to a furnace door through a hinge, an infrared thermometer is arranged on the inner surface of the furnace door, a weighing platform is arranged on the bottom of the detection box, the microwave heating device, the infrared thermometer and the weighing platform are all electrically connected to a controller, and the controller is electrically connected to the control panel.

[0007] Furthermore, the side wall of the detection box is provided with an exhaust device.

[0008] Furthermore, the outer shell of the microwave heating device is a rectangular parallelepiped structure, and a fan is arranged on the side wall, and the blowing direction of the fan is the inner space of the outer shell.

[0009] Furthermore, the control panel is fixed on the upper surface of the outer shell of the microwave heating device.

[0010] Furthermore, a heat-insulating material is provided on the inner wall of the detection box.

[0011] Furthermore, the control panel includes a digital display panel and operation buttons, and the digital display panel and the operation buttons are electrically connected to the controller. The digital display panel provides information such as temperature and time, soil weight and basic soil properties, and the operation buttons are used to control the heating temperature and heating time.

[0012] Furthermore, the microwave frequency of the microwave heating device is 2.45 GHz.

[0013] Furthermore, a portable handle is installed on the outer side wall of the detection box.

[0014] Furthermore, a plurality of foot pads are installed at the bottom of the detection box.

[0015] Furthermore, the weighing platform includes a self-leveling weighing platform or a common weighing platform.

[0016] The portable rapid determination device for physical properties of undisturbed soil foundation also includes a matching tool ring cutter, which is used to take soil and control the volume of the soil sample, so that the soil taken each time is of a fixed volume.

[0017] The detection box is heated by the microwave heating device, and the temperature inside the box rises to evaporate the moisture in the soil, thereby making the soil dry.

[0018] Compared with the prior art, the present invention has the following beneficial effects:

[0019] 1. The present invention adopts a microwave heating device, which can increase the temperature more quickly than the traditional drying method heating device, and utilizes an exhaust device to accelerate water evaporation, which significantly improves the soil drying efficiency. It is suitable for rapid detection of basic soil properties at engineering sites, and greatly improves the efficiency of detecting basic soil properties.

[0020] 2. The present invention solves the problem that the traditional microwave oven drying method is difficult to control the temperature. The present invention can accurately control the temperature and is equipped with an automatically leveled soil weighing platform to ensure high accuracy in measuring the basic physical properties of the soil.

[0021] 3. Compared with traditional devices for detecting basic soil properties, the present invention can detect multiple basic soil properties with one device, solving the problem of complicated and diverse detection equipment. In addition, the invention has a simple structure, low cost, and a size and weight close to that of an ordinary household microwave oven. It is easy to carry and can be used in harsh outdoor environments. It is suitable for use in engineering site conditions and can ensure accurate detection results. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 This is a schematic diagram of the structure of a portable rapid determination device for physical properties of undisturbed soil foundation;

[0023] Figure 2 It is a schematic diagram of the structure of a microwave heating device;

[0024] Figure 3 This is the front view of the portable rapid determination device for physical properties of undisturbed soil foundation;

[0025] Figure 4 This is the left view of the portable rapid determination device for physical properties of undisturbed soil foundation;

[0026] Figure 5 It is a top view of a portable rapid determination device for physical properties of undisturbed soil foundation;

[0027] Figure 6 This is the main view of the ring cutter;

[0028] Figure 7 It is the top view of the ring cutter;

[0029] Figure 8 It is the side view of the ring knife;

[0030] Fig. 9 This is the operation flow chart of the portable rapid determination device of original soil foundation physical properties;

[0031] In the figure, 1. microwave heating device, 2. detection box, 3. control panel, 4. infrared thermometer, 5. weighing platform, 6. fan, 7. foot pad, 8. ring knife, 9. portable handle, 11. waveguide, 12. magnetron, 13. capacitor, 14. transformer, 21. furnace door, 22. exhaust device, 31. digital display panel, 32. operation button. DETAILED DESCRIPTION

[0032] The technical solution of the present invention will be clearly and completely described below in conjunction with the drawings and embodiments. Obviously, the described embodiments are only part of the embodiments of the invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0033] Embodiment 1:

[0034] like Figure 1-8 As shown, the present invention provides a portable rapid determination device for physical properties of undisturbed soil foundation, comprising a microwave heating device 1, a detection box 2 and a control panel 3, wherein a furnace door 21 is hingedly connected to the top of the detection box 2, an infrared thermometer 4 is arranged on the inner surface of the furnace door 21, and the infrared thermometer 4 is used to detect the real-time temperature in the furnace, a weighing platform 5 is arranged at the bottom of the detection box 2, the microwave heating device 1, the infrared thermometer 4 and the weighing platform 5 are all electrically connected to a controller, and the controller is electrically connected to the control panel 3.

[0035] Furthermore, an exhaust device 22 is provided on the side wall of the detection box 2 .

[0036] Furthermore, a fan 6 is provided on the side wall of the outer shell of the microwave heating device 1, and the blowing direction of the fan 6 is the inner space of the outer shell.

[0037] Furthermore, the control panel 3 is fixed on the upper surface of the outer shell of the microwave heating device 1 .

[0038] Furthermore, a heat-insulating material is provided on the inner wall of the detection box 2 .

[0039] Furthermore, the control panel 3 includes a digital display panel 31 and an operation button 32, and the digital display panel 31 and the operation button 32 are both electrically connected to the controller. The digital display panel 31 displays the temperature information, the material temperature range, and the material temperature time curve obtained by the infrared temperature detector 4; the operation button 32 is used to control the power input and switch of the microwave heating device 1.

[0040] Furthermore, the microwave frequency of the microwave heating device 1 is 2.45 GHz.

[0041] Furthermore, portable handles 9 are installed on both sides of the symmetrical outer side walls of the detection box.

[0042] Furthermore, a plurality of foot pads 7 are installed at the bottom of the detection box 2 . The number of the foot pads 7 is 4 and they are evenly distributed at the four bottom corners of the detection box 2 .

[0043] Furthermore, the weighing platform 5 includes a self-leveling weighing platform or a common weighing platform.

[0044] The portable rapid determination device for physical properties of undisturbed soil foundation also includes a matching tool ring knife 8, which is used to take soil and control the volume of the soil sample, so that the soil taken each time is a fixed volume. Since microwave heating is used, the material of the ring knife 8 is ceramic or other materials with similar properties. The ring knife 8 is placed on the weighing platform 5.

[0045] The microwave heating device 1 comprises a waveguide 11, a magnetron 12, a capacitor 13 and a transformer 14, which are all mounted on the bottom surface of the outer shell by bolts. The control panel 3 is located on the upper surface of the outer shell of the microwave heating device 1. After power is turned on, a 220V voltage is added to the primary of the transformer, and the secondary outputs two groups of AC voltages of 3V-4V and 1800V-2230V. The 3V-4V AC voltage directly supplies power to the operation button 32 and the digital display panel 31; the 1800V-2230V AC voltage is rectified and filtered by the capacitor 13 to become a negative DC voltage of 3600V-4500V, which is added to the magnetron 12 to generate 2.45GHz ultra-high frequency electromagnetic waves, i.e. microwaves.

[0046] The detection box 2 is heated by the microwave heating device 1, and the temperature inside the box rises to evaporate the moisture in the soil, thereby putting the soil in a dry state. The specific process is: the microwave heating device 1 generates microwaves through the magnetron 12, which quickly vibrates the water molecules in the soil, causing them to generate heat and evaporate. The water vapor generated by evaporation is quickly discharged from the inside of the cavity by the exhaust device 22, thereby accelerating the evaporation of moisture in the soil. The heating temperature is set by operating the button 32, and the time for the control circuit to provide 220V voltage to the transformer is changed, that is, a power supply cycle is set to ensure that the temperature of the soil fluctuates slightly within a precise temperature range, thereby solving the problem that the traditional microwave drying method cannot control the temperature.

[0047] In the present invention, a fixed volume of soil is taken by using a ring knife 8, and the self-leveling weighing platform at the bottom automatically records the weight of the water-containing soil before heating and displays it on the digital display panel 31. Since the weighing platform 5 has a self-leveling function, even when the soil moisture content is detected in an unstable place, it can be ensured that the soil in the ring knife 8 will not spill onto the weighing platform 5 or other places, thereby affecting the accuracy of the detection result.

[0048] In the present invention, the wet density of soil is calculated using the following formula:

[0049] In the formula, ρ w represents the wet density of soil, m w Represents the mass of wet soil, V a Indicates the volume of the ring cutter.

[0050] In the present invention, the soil dry density is calculated using the following formula:

[0051] In the formula, ρ d Represents the dry density of soil, M d is the dry soil mass, V a is the volume of the ring cutter.

[0052] In the present invention, the soil moisture content is calculated using the following formula:

[0053] In the formula, s represents soil moisture content, m w Indicates the mass of soil before drying, m d Indicates the mass of soil after drying.

[0054] In the present invention, the porosity ratio is measured by the following principle, that is, a fixed volume of soil sample is taken by a ring knife 8, and then the soil mass m after microwave heating and drying is obtained by using the peeling function of the self-leveling weighing table. d , the preset program automatically calculates the soil dry density ρ d , that is, the ratio of the mass of the dried soil to the volume of the ring cutter 8, and the particle density ρ of the dried soil sample is obtained by the pycnometer method s , the soil porosity ratio can be calculated using the following formula:

[0055] Where e represents the soil porosity, ρ d is the soil dry density, ρ s is the soil particle density.

[0056] Embodiment 2:

[0057] like Fig. 9 As shown, a method for measuring the basic physical properties of undisturbed soil using the measuring device described in Example 1 is carried out according to the following steps:

[0058] Step 1: Allow the self-leveling weighing platform to automatically level, place the ring knife 8 on the weighing platform 5 to zero, and use the ring knife 8 to take a fixed volume of soil at the testing site or indoor laboratory.

[0059] Step 2: Open the furnace door 21, place the ring knife 8 containing the test soil sample on the self-leveling weighing table that has been adjusted to zero, and the weight of the water-containing soil will be displayed on the digital display panel 31.

[0060] Step 3: Press the record button on the operation button 32, the detector records the initial weight of the soil sample, press the button to start heating, if the furnace door 21 is not closed, the buzzer will sound a reminder to close the furnace door 21, after closing the furnace door 21, enter the heating temperature T and start high-power heating, if the soil sample temperature detected by the infrared thermometer 4 is lower than the set temperature T, maintain high-power heating, otherwise adjust to low-power heating, ensure that the soil sample temperature is within the set temperature T±0.5℃, turn on the heating and the exhaust device 22 starts to operate, accelerate the discharge of water vapor in the soil sample from the cavity, the detector records the weight change of the soil sample obtained by the weighing platform 5 in real time, if within 1 minute, the soil mass remains unchanged at the 0.001g accuracy of the weighing platform, it is judged that the soil sample is in a dry state, then stop heating and automatically output the results of water content, dry density and wet density, then use the specific gravity bottle method to calculate the particle density of the dried soil, input the particle density value into the detector, and the internal program automatically calculates the soil porosity, thus completing the basic physical property detection of the soil.

[0061] The present invention sets the power of the microwave heating device 1 by operating a button, uses the microwave heating device 1 to heat the water-containing soil sample to make the soil sample dry, and uses a self-leveling weighing platform to obtain the weight of water in the soil sample to calculate the soil moisture content. A fixed volume of soil is taken by a ring knife 8 and combined with a specific gravity bottle method, so that the program can automatically calculate the dry density, wet density and porosity ratio of the detected soil. The present invention improves the efficiency of determining the basic physical properties of the original soil in actual engineering and avoids the disturbance of the original soil during transportation.

[0062] In addition, it should be understood that although the present specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

Claims

1. A portable rapid determination device for physical properties of undisturbed soil foundation, characterized in that: The invention comprises a microwave heating device (1), a detection box (2) and a control panel (3); a furnace door (21) is hinged on the top of the detection box (2); an infrared thermometer (4) is arranged on the inner surface of the furnace door (21); a weighing platform (5) is arranged on the bottom of the detection box (2); the microwave heating device (1), the infrared thermometer (4) and the weighing platform (5) are all electrically connected to a controller; and the controller is electrically connected to the control panel (3).

2. A portable rapid determination device for physical properties of undisturbed soil foundation according to claim 1, characterized in that: An exhaust device (22) is provided on the side wall of the detection box (2).

3. A portable rapid determination device for physical properties of undisturbed soil foundation according to claim 1, characterized in that: A fan (6) is arranged on the side wall of the outer shell of the microwave heating device (1), and the blowing direction of the fan (6) is the internal space of the outer shell.

4. A portable rapid determination device for physical properties of undisturbed soil foundation according to claim 1, characterized in that: The control panel (3) is fixed on the upper surface of the outer shell of the microwave heating device (1).

5. A portable rapid determination device for physical properties of undisturbed soil foundation according to claim 1, characterized in that: A heat-insulating material is provided on the inner side wall of the detection box (2).

6. A portable rapid determination device for physical properties of undisturbed soil foundation according to claim 1 or 4, characterized in that: The control panel (3) comprises a digital display panel (31) and operating buttons (32), and both the digital display panel (31) and the operating buttons (32) are electrically connected to the controller.

7. A portable rapid determination device for physical properties of undisturbed soil foundation according to claim 1, characterized in that: The microwave frequency of the microwave heating device (1) is 2.45 GHz.

8. The portable rapid determination device for physical properties of undisturbed soil foundation according to claim 1 is characterized by: A portable handle (9) is installed on the outer side wall of the detection box.

9. A portable rapid determination device for physical properties of undisturbed soil foundation according to claim 1, characterized in that: A plurality of foot pads (7) are installed at the bottom of the detection box (2).

10. The portable rapid determination device for physical properties of undisturbed soil foundation according to claim 1, characterized in that: The weighing platform (5) is a self-leveling weighing platform or a common weighing platform.

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