A combined measuring device for water content and soil dynamic penetration characteristics

Abstract

The present invention relates to the field of geotechnical testing technology, and proposes a combined determination device for moisture content and soil dynamic probing characteristics, including a probing rod having a probe portion; an insulating sleeve arranged on the probing rod, located on a side away from the probe portion; four conductive members, evenly spaced around the insulating sleeve, the main body of the conductive member is located inside the insulating sleeve, and one end thereof is used to contact the soil. Through the above technical scheme, the problems existing in the existing testing technology, such as poor durability of moisture content measuring devices, high test errors, unclear test ranges, long test cycles, and the need to make substantial changes to the original instrument and equipment or the original equipment cannot be reused when using the instrument for testing, resulting in excessively high costs, and cumbersome operations during application are solved.

Description

Technical Field

[0001] The invention relates to the technical field of geotechnical testing, and in particular to a combined determination device for water content and soil dynamic penetration characteristics. Background Art

[0002] During the operation, the roadbed often produces settlement and deformation, which will threaten the safety of roadbed operation and seriously affect the traffic efficiency. In order to ensure the rapid and safe passage of vehicles, it is necessary to explore the soil with diseases to deeply explore the causes of the development of diseases. Drilling sampling and indoor testing are often used to determine the mechanical properties of the soil, and corresponding reinforcement plans are formulated based on the parameters. The existing sampling method is an important means to obtain on-site soil, but there are also some problems. For example, the drilling sampling method may disturb the soil sample, and the sampling process requires relatively large engineering machinery, resulting in high sampling costs. The on-site soil samples are sent to the laboratory for measurement by the drying method. The drying method for measuring the moisture content of the soil takes a certain amount of time, resulting in a long analysis cycle, which will have a great impact on busy transportation. Therefore, it is of great significance to develop a moisture content measurement device that can jointly measure the mechanical properties of the soil and the moisture content for the prevention and control of roadbed diseases.

[0003] In the process of roadbed soil exploration, dynamic probing is often used for detection. Dynamic probing is an in-situ test method commonly used in geotechnical engineering investigation and foundation testing. It is divided into light, heavy and super heavy according to the weight of the core hammer. A core hammer of a certain mass is used to fall freely from the top of the core rod along the core rod at a fixed height, so that the cone probe overcomes the friction resistance and tip resistance of the soil, and drives the cone probe into the soil layer. According to the number of hammer strikes required for the probe to penetrate a certain depth into the soil, the correlation between the number of hammer strikes and the soil density and liquefaction index is established based on relevant specifications or engineering experience, and the mechanical properties of the soil are determined. Lightweight dynamic penetration test has the advantages of easy operation and strong applicability, and is increasingly used in engineering surveys. However, penetration test can often only measure parameters such as soil density, and the important influencing parameter, soil moisture content, cannot be effectively measured. The measurement of roadbed moisture content often requires sending soil samples to the laboratory and measuring soil moisture content through indoor test methods, which will take a certain amount of time and will affect the disposal decision of the roadbed and even the roadbed traffic efficiency.

[0004] To solve the above problems, technical solutions for measuring soil moisture content have been proposed in the prior art. For example, the patent with announcement number CN219065170U discloses a probe with a moisture sensor protection structure. By adding a moisture sensor to the probe, the moisture content of the soil is measured with the help of the moisture sensor. The moisture sensor protection layer is easy to wear, and it is necessary to add a sensor protection structure. During the test, when the sensor measures the moisture content of the soil, the protection structure needs to be pulled out. There must be a gap between the sensor and the soil, which makes the moisture content measurement range unclear and often causes a high test error. At the same time, during the measurement of the next point, the protection structure needs to be inserted. The moisture sensor is often sticky with dirt such as mud from the previous test position, and the test error is large when measuring the next point. Since the moisture content test probe is buried in the soil, it is difficult to insert and remove the protection device under the action of soil resistance. In the field test, the tester needs to insert and remove the protection structure many times when measuring the moisture content of the soil. The use process is cumbersome and will greatly increase the workload. Moreover, the moisture content sensor is relatively fragile and often needs to be replaced when damaged, which will increase the engineering cost and is difficult to adapt to the harsh test environment in the field. At the same time, the implementation of this method requires major improvements or new modifications to the original device structure, which will limit its application scope and use effect.

[0005] Another example is the patent with announcement number CN214333871U, which discloses a dynamic probing device that can measure the moisture content of soil. The soil moisture content is measured by adding a resistivity sensor to the probing rod. However, the resistivity sensor of the device is installed on the probing rod, which will change the friction resistance and tip resistance of the device, causing changes in the interface characteristics. The dynamic probing device mainly measures the soil properties through the friction resistance of the probing rod, which will cause a large test error in the test results of the dynamic probing. In order to prevent the soil from entering the probing rod, protective devices such as permeable membranes and permeable stones are installed on the outside of the resistivity sensor. The permeable stones and permeable membranes will inevitably be wetted or dried during the test. When measuring the moisture content of the soil, the moisture content of the permeable stone will inevitably be calculated, which will cause errors in the measurement of the moisture content of the soil. At the same time, the moisture content test probe is located in a conical metal probe, which cannot rule out the influence of the metal conductor on the test. In the process of measuring the moisture content of the soil, the range of the measured soil moisture content is unclear.

[0006] Through the soil moisture measurement device and test method studied above, a moisture measurement device is often added to the probe part to measure the soil moisture content. However, the added moisture measurement device has the disadvantages of poor durability, unclear test range, added protection mechanism changes the interface effect, and large test error. Specifically: the added soil moisture measurement device has poor durability and needs to add additional auxiliary protection devices, which will increase the complexity of the structure and is not conducive to promotion during use. The addition of auxiliary protection devices changes the interface effect of the probe part, changes the friction resistance and tip resistance of the probe part, and cannot accurately measure the soil moisture content without interfering with the soil dynamic penetration test. At the same time, the addition of auxiliary protection devices often interferes with the moisture measurement and produces large test errors. Therefore, in the existing soil moisture measurement technology, due to the change of the interface characteristics of the penetration rod and the unclear test range, the addition of measurement auxiliary devices will affect the compaction characteristics of the soil, that is, the measured soil density and other related parameters are greatly different from the actual values, causing large test errors. At the same time, in the actual application process of the above devices, it is often necessary to redesign or transform the structure of the original devices, and it is necessary to eliminate existing equipment and purchase new equipment, which will create certain obstacles to the promotion and use of the measuring device. Summary of the invention

[0007] The present invention proposes a combined determination device for water content and dynamic penetration characteristics of soil, which solves the problems existing in the existing testing technology, namely, poor durability of water content measuring devices, high test error, unclear test range, long test cycle, and the need to make major changes to the original instruments and equipment or to reuse the original equipment when using the instrument for testing, resulting in excessively high costs, as well as the problem of complicated operations during the application process.

[0008] The technical solution of the present invention is as follows: a combined determination device for water content and soil dynamic penetration characteristics, comprising:

[0009] The feeler rod has a probe portion;

[0010] An insulating sleeve, the insulating sleeve is arranged on the probe rod and is located at a side away from the probe part;

[0011] The conductive member has four conductive members which are evenly spaced and arranged around the insulating sleeve. The main body of the conductive member is located inside the insulating sleeve, and one end of the conductive member is used to contact the soil.

[0012] Optionally, it also includes:

[0013] Conductors, wherein there are four conductors, and one end of each of the conductors is electrically connected to one of the conductive members;

[0014] The other end of the wire is electrically connected to the moisture content measuring device.

[0015] Optionally, the feeler rod has an inclined first slope surface, and the insulating sleeve has an inclined second slope surface, the first slope surface and the second slope surface are parallel to each other, and the end of the first slope surface close to the axis of the feeler rod is higher or lower than the end away from the axis of the feeler rod.

[0016] Optionally, the inclination angle of the first slope is α, 0.3≤tanα≤0.6.

[0017] Optionally, the insulating sleeve has a plurality of mounting holes for mounting the conductive member, the mounting holes have internal threads, the conductive member has external threads, the conductive member is threadedly connected to the mounting holes, the feeler rod has a first connecting hole, and the insulating sleeve has a second connecting hole; and further comprising:

[0018] A connecting member having a connecting portion, wherein the connecting portion passes through the second connecting hole, enters the first connecting hole, and is connected to the feeler rod.

[0019] Optionally, the connecting member has a pressing portion, and the pressing portion abuts against an end surface of the insulating sleeve away from the feeler rod.

[0020] Optionally, the insulating sleeve further has a plurality of first wire holes, the first wire holes are connected to the mounting hole, and the diameter of the first wire holes is smaller than the diameter of the mounting hole;

[0021] The connecting piece has a first inner cavity, the first inner cavity has a plurality of second wire holes, the apertures of the second wire holes are the same as the apertures of the first wire holes, and the second wire holes are communicated with the first wire holes.

[0022] The rod body is arranged on the connecting piece and has a second inner cavity. The first inner cavity is communicated with the second inner cavity. The wire passes through the first wire hole, the second wire hole, the first inner cavity and the second inner cavity.

[0023] Optionally, the four conductive members are numbered Q, W, E, and R in the same direction, and a constant current I is alternately applied to the conductive member Q and the conductive member W. QW , measure the voltage U between the conductive part E and the conductive part R ER , a constant current I is generated to the conductive parts E and R ER , measure the voltage U between the conductive part Q and the conductive part W QW , multiple groups I QW and U ER ,I ER and U QWSubstitute the value into the soil conductivity ρ calculation formula: ρ = K (U ER / I QW +U QW / I ER ), multiple groups of different soil conductivity ρ are calculated.

[0024] Optionally, multiple groups of soils with different electrical conductivities ρ are placed in a drying box for drying to obtain soil moisture content ω;

[0025] Put multiple groups of soils with different electrical conductivities ρ into a drying box for drying, and obtain the soil moisture content ω;

[0026] The soil moisture content at a distance of H*n from the ground is W Hn The measured soil moisture content at this point is W Hn1 , the interference term is denoted as W Hn2 ; Substitute the soil moisture content W into the correction calculation formula: W Hn = W Hn1 + W Hn2 .

[0027] Optionally, W Hn2 is the soil moisture content and W measured by the front X-stroke and the back X-stroke at the H*n position Hn1 The mean of the differences is:

[0028] W Hn2 ={(W （Hn1）-X -W Hn1 )+ (W （Hn1）-(X-1) -W Hn1 )+...+(W （Hn1）-1 -W Hn1 )+(W （Hn1）+1 -W Hn1 )+...+(W （Hn1）+X -W Hn1 )} / 2X.

[0029] The working principle and beneficial effects of the present invention are:

[0030] In the present invention, the sounding rod is the sounding end of the dynamic sounding, and is hammered into the roadbed to be measured by a sounding hammer. The size of the probe part of the sounding rod is completely the same as the specifications and dimensions of the sounding rod required by the specification, and the friction resistance of its cross section is consistent with the specification requirements, that is, the sounding rod realizes the joint measurement of water content and dynamic characteristics of soil without changing its interface properties.

[0031] The insulating sleeve is arranged on the feeler rod, preferably, on the side of the feeler rod away from the probe part. During the measurement process, the feeler rod contacts the soil. Under the hammering action of the core hammer, the feeler rod moves downward. When the insulating sleeve reaches the predetermined moisture content test position, it is connected to the moisture content measuring device on the top through four conductive parts evenly distributed on its outside. At the same time, the insulating sleeve arranged on the feeler rod has high strength, durability and wear resistance. Therefore, the device does not need to be equipped with additional protective devices during the test process to reduce structural redundancy, reduce workload during operation, improve labor efficiency, and further increase the possibility of its promotion and application. At the same time, according to the material selection and field test, on the basis of meeting strength, durability, wear resistance, insulation and economy, it is appropriate to select polytetrafluoroethylene as the material of the insulating sleeve.

[0032] The conductive parts are installed on the insulating sleeve. There are four conductive parts, which are evenly spaced, that is, 90 degrees apart from each other. This arrangement can form a more uniform electric field distribution in the soil. In the electric field simulation experiment, the electric field uniformity coefficient under this arrangement is as high as 0.92. Compared with the unevenly arranged conductive parts, the standard deviation of the test results is reduced by at least 10%, which makes it possible to more accurately measure the conductivity of the soil and obtain more accurate moisture content data.

[0033] The probing rod composed of the probe part, insulating sleeve, conductive part and connecting assembly was found to have basically the same friction resistance and dynamic properties as the probing rod of the traditional light dynamic probe during the test. The test found that on the same test roadbed section, when the same depth was hammered, the number of hammering times differed by ±2, which basically met the requirements of the relevant design specifications, that is, the soil moisture content was measured while the dynamic characteristics of the soil were measured, and the impact was reduced to a minimum. At the same time, it was found that after the four conductive parts were tested, their surfaces still had a good smoothness, and the possibility of contaminated soil and the like causing errors in the test was reduced. After a long period of observation, the composite composed of the conductive part and the insulating sleeve had a low degree of wear during long-term use, and could basically adapt to the measurement of moisture content and dynamic characteristics in complex outdoor geological conditions.

[0034] When the sounding rod composed of a conductive part and an insulating sleeve is used to measure the moisture content of soil, its basic principle is that the moisture content measuring device located at the top is connected to the four conductive parts through four wires respectively, and the test system transmits electrical signals to two of the four conductive parts, and the other two conductive parts receive the electrical signals. Due to the different moisture contents of the soil, their conductive properties will also be different, so the strength of the received electrical signals will be changed, and then the moisture content of the soil at this position is measured by transmitting the electrical signals to the moisture content measuring device at the top.

[0035] During the measurement process, the frequency of the transmitting and receiving signals can be adjusted. By setting a fixed frequency, the soil at the position can be measured and recorded according to the set sampling frequency during the hammering process. At the same time, the moisture content measuring device can also realize manual measurement of the moisture content when it reaches the specified measurement position. That is, when it reaches the specified position, the moisture content of the point can be roughly measured by manually entering the test depth and pressing the moisture content measurement button. When the probe and the connecting rod move under the action of the core hammer, the position of the complex composed of the conductive part and the insulating sleeve will move. The conductive part measures the moisture content at the established frequency under the action of the moisture content measuring device. After calculation, it is known that the hammering interval is ≥15S each time the technician hammers, so the sampling interval of the moisture content measuring device is ≤6S. During the hammering process, the position will change suddenly, which will cause the strength of the signal received by the test electrode receiving the electrical signal to change, so the moisture content measuring device will capture the corresponding changes. By setting a suitable threshold, it is possible to distinguish between small fluctuations during normal measurement and large changes caused by hammering and displacement. By recording the number of current or voltage changes exceeding the threshold, the soil conductivity and the number of knocks can be recorded simultaneously. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] The preferred implementation modes will be described below in a clear and understandable manner with reference to the accompanying drawings to further illustrate the above-mentioned characteristics, technical features, advantages and implementation methods of the present invention.

[0037] Figure 1 It is a schematic diagram of the structure of the present invention;

[0038] Figure 2 It is a schematic diagram of the internal cross-sectional structure of the present invention;

[0039] Figure 3 It is a schematic diagram of the explosion structure of the probe rod, the insulating sleeve and the connecting piece of the present invention;

[0040] Figure 4 It is a schematic diagram of the structure of the feeler rod and the insulating sleeve of the present invention (the first slope is inclined upward);

[0041] Figure 5 The electric field distribution diagram is measured for the present invention.

[0042] In the figure: 1. probe rod; 101. probe part; 102. first connecting hole; 2. insulating sleeve; 201. mounting hole; 202. first wire hole; 203. second connecting hole; 3. conductive part; 4. conductive wire; 5. moisture content measuring device; 6. first slope surface; 7. second slope surface; 8. connecting part; 801. connecting part; 802. pressing part; 803. first inner cavity; 804. second wire hole; 9. rod body; 10. marking line. DETAILED DESCRIPTION

[0043] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the specific implementation methods of the present invention will be described below with reference to the accompanying drawings. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings and other implementation methods can be obtained based on these drawings without creative work.

[0044] In order to simplify the drawings, only the parts related to the invention are schematically shown in each figure, and they do not represent the actual structure of the product. In addition, in order to simplify the drawings and facilitate understanding, in some figures, only one of the parts with the same structure or function is schematically shown, or only one of them is marked. In this article, "one" not only means "only one", but also means "more than one", and "several" includes "two" and "more than two".

[0045] In this document, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0046] In addition, in the description of the present application, the terms "first", "second", etc. are only used to distinguish the description and cannot be understood as indicating or implying relative importance.

[0047] Reference Figure 1~Figure 5 A combined determination device for moisture content and soil dynamic probing characteristics is proposed, comprising: a probing rod 1 having a probe portion 101; an insulating sleeve 2 is arranged on the probing rod 1 and is located on a side away from the probe portion 101; four conductive members 3 are evenly spaced and arranged around the insulating sleeve 2, the main body of the conductive member 3 is located inside the insulating sleeve 2, and one end of the conductive member 3 is used to contact the soil.

[0048] In this embodiment, the sounding rod 1 is the sounding end of the dynamic sounding, and is hammered into the roadbed to be measured by a sounding hammer. The size of the probe part 101 of the sounding rod 1 is exactly the same as the specifications and dimensions of the sounding rod 1 required by the specification. At the same time, the friction resistance of its cross section is consistent with the specification requirements, that is, the sounding rod 1 realizes the combined measurement of water content and dynamic characteristics of soil without changing its interface properties.

[0049] The insulating sleeve 2 is arranged on the feeler rod 1, preferably, it is arranged on the side of the feeler rod 1 away from the probe part 101. During the measurement process, the feeler rod 1 contacts the soil. Under the hammering action of the core hammer, the feeler rod 1 moves downward. When the insulating sleeve 2 reaches the predetermined moisture content test position, it is connected to the moisture content measuring device 5 on the top through four conductive parts 3 evenly distributed on its outside, wherein the moisture content measuring device 5 is composed of several single-chip microcomputers containing digital processing chips and electrical signal processing chips, a power supply module, and a voltage measurement module, which can realize data collection and processing, and can export test data to a specified position. At the same time, the insulating sleeve 2 arranged on the feeler rod 1 has high strength, durability and wear resistance. Therefore, the device does not need to be provided with additional protective devices during the test process, so as to reduce the redundancy of the structure, reduce the workload during the operation process, improve labor efficiency, and further increase the possibility of its promotion and application. At the same time, according to the material selection and field test, on the basis of meeting the strength, durability, wear resistance, insulation and economy, it is appropriate to select polytetrafluoroethylene as the material of the insulating sleeve 2.

[0050] The conductive member 3 is installed on the insulating sleeve 2. There are four conductive members 3, which are evenly spaced, that is, 90 degrees apart from each other. Such an arrangement can form a more uniform electric field distribution in the soil. In the electric field simulation experiment, the electric field uniformity coefficient under this arrangement is as high as 0.92. Compared with the unevenly arranged conductive members 3, the standard deviation of the test results is reduced by at least 10%, which makes it possible to more accurately measure the conductivity of the soil and obtain more accurate moisture content data.

[0051] The sounding rod 1 composed of the probe part 101, the insulating sleeve 2, the conductive part 3, and the connecting assembly was found to have basically the same friction resistance and dynamic properties as the sounding rod 1 of the traditional light dynamic sounding instrument during the test. Through the test, it was found that on the same test roadbed section, when the hammer hits the same depth, the number of hammer hits differed by ±2, which basically met the requirements of the relevant design specifications, that is, the soil moisture content was measured while the dynamic characteristics of the soil were measured, and the impact was reduced to a minimum. At the same time, it was found that after the test of the four conductive parts 3 was completed, their surfaces still had a good smoothness, and the possibility of contaminated soil and the like causing errors in the test was reduced. After a long period of observation, the composite composed of the conductive part 3 and the insulating sleeve 2 had a low degree of wear during long-term use, and could basically adapt to the measurement of moisture content and dynamic characteristics of complex outdoor geological conditions.

[0052] When the sounding rod 1 composed of a conductive part 3 and an insulating sleeve 2 is used to measure the moisture content of soil, its basic principle is that the moisture content measuring device 5 located at the top is connected to the four conductive parts 3 through four wires 4 respectively, and the test system transmits electrical signals to two conductive parts 3 among the four conductive parts 3, and the other two conductive parts 3 receive the electrical signals. Different soil moisture contents correspond to different strengths of received electrical signals, and then the soil moisture content at this position is measured by transmitting the electrical signal to the moisture content measuring device 5 at the top.

[0053] During the measurement process, the frequency of the transmitting and receiving signals can be adjusted, and a fixed frequency can be set, so that the soil moisture content ω can be automatically recorded during the hammering process. At the same time, the moisture content measuring device 5 can also realize the manual measurement of the soil moisture content ω when it reaches the specified measurement position. When the probe rod 1 moves under the action of the core hammer, the position of the complex composed of the conductive member 3 and the insulating sleeve 2 will move. The conductive member 3 measures the moisture content according to the established frequency under the action of the moisture content measuring device 5. After calculation, it is known that the hammering interval is ≥15S each time the technician hammers, so the sampling interval of the moisture content measuring device 5 is ≤6S. During the hammering process, the position change will also cause a sudden change in the electric field, so the moisture content measuring device 5 will capture the corresponding changes. By setting a suitable threshold, it is possible to distinguish between small fluctuations during normal measurement and large changes caused by hammering and displacement. The simultaneous recording of soil conductivity and the number of knocks can be achieved by recording the number of current or voltage changes exceeding the threshold.

[0054] Furthermore, it also includes: there are four wires 4, one end of each wire 4 is electrically connected to a conductive member 3; and the other end of the wire 4 is electrically connected to the moisture content measuring device 5.

[0055] In this embodiment, four conductive members 3 are taken as an example, each conductive member 3 is electrically connected to a moisture content measuring device 5 through a wire 4, wherein the moisture content measuring device 5 is a voltage tester and a current source, the voltage tester is used to test the voltage signal between two adjacent conductive members 3, and the current source is used to provide current to the other two adjacent conductive members 3 through the wire 4. Specifically, in actual use, the four conductive members 3 are numbered Q, W, E, and R, respectively, and the four are arranged in sequence in one direction, and a constant current I is generated to the conductive members 3Q and 3W. QW , measure the voltage U between conductive part 3E and conductive part 3R ER , a constant current I is generated to the conductive member 3E and the conductive member 3R ER , measure the voltage U between the conductive part 3Q and the conductive part 3W QW , and refer to the formula: ρ = K (U ER / I QW +U QW / I ER), K is a parameter related to the diameter of the conductive part 3 and the size of the insulating sleeve 2, K=(1 / r+1 / h)*1 / ln2, where r is the diameter of the conductive part 3 and h is the height of the insulating sleeve 2. The soil moisture content is further calculated by the soil conductivity, and the calculation theoretical equation is ω=Aρ B , where ω is the soil moisture content, A and B are fitting parameters obtained through experimental calibration. Further, through the above calculation theory, the electrical signal is converted into a moisture content signal and displayed and recorded.

[0056] According to the requirements of the Geotechnical Investigation Code, the number of times the cone head penetrates 30cm into the soil should be recorded, so a marking line is drawn every 30cm on the probe. In order to meet the test accuracy requirements of the roadbed moisture content, the roadbed height is often as high as 7-10m, so the moisture content is measured every 15cm, which can basically meet the accuracy requirements of drawing the moisture content curve with depth. Therefore, the following moisture content algorithm is illustrated by the above embodiment. In order to reduce the interference of system errors on the test results, the moisture content calculation method is improved.

[0057] Since the soil moisture content is measured every 15 cm from the reference surface (or ground), the moisture content at this point is recorded as W 15n The soil moisture content at this point measured by the probe is W 15n1 , the interference term of the system on the test results is reduced by the calculation algorithm and recorded as W 15n2 .

[0058] The calculation formula for soil moisture content correction is: W 15n = W 15n1 + W 15n2 , W 15n2 The moisture content and W measured by the first 3 hits and the last 3 hits at the 15n position 15n1 The mean of the difference in moisture content measured at the location is calculated as: W 15n2 ={(W （15n1）-3 -W 15n1 )+(W （15n1）-2 -W 15n1 )+(W （15n1）-1 -W 15n1 )+(W （15n1）+1 -W 15n1 )+(W （15n1）+2 -W 15n1 )+(W （15n1）+3 -W 15n1 )} / 6.

[0059] The moisture content calculation method can substantially eliminate the systematic error of the moisture content measurement at the specified position. The moisture content calculation method and the operation logic are encoded to the moisture content measurement device 5 through the encoder.

[0060] Furthermore, the feeler rod 1 has an inclined first slope 6, and the insulating sleeve 2 has an inclined second slope 7. The first slope 6 and the second slope 7 are parallel to each other, and the end of the first slope 6 close to the axis of the feeler rod 1 is higher or lower than the end away from the axis of the feeler rod 1.

[0061] In this embodiment, reference Figure 2 and Figure 4 The first slope 6 has two inclined settings. The first is that the end of the first slope 6 close to the axis of the probe rod 1 is higher than the end away from the axis of the probe rod 1, that is, it is inclined downward. The second is that the end of the first slope 6 close to the axis of the probe rod 1 is lower than the end away from the axis of the probe rod 1, that is, it is inclined upward. Both methods can effectively prevent soil particles from entering between the probe rod 1 and the insulating sleeve 2, providing better sealing.

[0062] Furthermore, the end of the first slope 6 close to the axis of the feeler rod 1 is lower than the end away from the axis of the feeler rod 1, and the inclination angle is α, 0.3≤tanα≤0.6.

[0063] In this embodiment, reference Figure 4 As a preferred method, the second type is selected, which is inclined upward, because its inclined direction is opposite to the drilling direction of the probe rod 1, which can better improve the soil-proof effect and sealing of the equipment and reduce the entry of soil particles and impurities into the gap between the probe rod 1 and the insulating sleeve 2. This design not only improves the accuracy and reliability of the test results, but also extends the service life of the equipment, reduces maintenance costs, and enables the probe rod 1 to provide consistent test results under a variety of soil types and environmental conditions.

[0064] Furthermore, the insulating sleeve 2 has a plurality of mounting holes 201 for mounting the conductive member 3, the mounting holes 201 have internal threads, the conductive member 3 has external threads, and the conductive member 3 is threadedly connected to the mounting holes 201; the feeler rod 1 has a first connection hole 102, and the insulating sleeve 2 has a second connection hole; and further includes: a connector 8, the connector 8 has a connecting portion 801, the connecting portion 801 passes through the second connection hole, enters the first connection hole 102, and is connected to the feeler rod 1. The connector 8 has a pressing portion 802, and the pressing portion 802 abuts against the end face of the insulating sleeve 2 away from the feeler rod 1;

[0065] In this embodiment, the conductive member 3 is fixed to the insulating sleeve 2 by means of a threaded connection. A plurality of mounting holes 201 with internal threads are preset inside the insulating sleeve 2, and the conductive member 3 is provided with corresponding external threads. When the conductive member 3 needs to be installed, it is only necessary to align the external thread portion of the conductive member 3 with the mounting hole 201 on the insulating sleeve 2 and rotate it until it is fully tightened to complete the installation. When the probe rod 1 reaches the specified position, an electric field is passed through the four conductive members 3 to measure the corresponding electric field distribution. This connection method can not only ensure a stable physical connection between the conductive member 3 and the insulating sleeve 2, but also ensure good electrical continuity. In addition, since the threaded connection has a certain self-locking function, it can effectively prevent the conductive member 3 from loosening due to external factors (such as temperature changes, mechanical vibrations, etc.) under normal operating conditions, thereby ensuring the stable operation of the entire system. The setting of the insulating sleeve 2 will help to isolate the influence of the metal part of the probe rod 1 on the electric field distribution.

[0066] In addition, one end of the conductive part 3 is located inside the insulating sleeve 2 and connected to the connecting wire 4, and the other end is located slightly protruding outside the insulating sleeve 2. The protruding part can be elliptical or circular. This shape gives the conductive part 3 higher strength and self-cleaning properties. During the hammering process, the conductive part 3 maintains good contact with the outer soil. Due to its good wear resistance and high strength, it does not need to set up additional protective mechanisms. During the measurement process, such as from one depth through hammering, in the process of descending to another specified depth, the surface of the conductive part 3 will basically not have the soil of the previous measuring point, so the test result is the true value of the position of the probe rod 1, avoiding the test error caused by the moisture content test result caused by the protective mechanisms such as permeable stone and permeable membrane, and at the same time reducing the hysteresis of the test result caused by the migration of soil moisture to its structure due to the setting of protective mechanisms such as permeable stone and permeable membrane. At the same time, if the next measuring point is tested, it is necessary to redistribute the moisture of the protective structures such as the permeable stone and the permeable membrane. This will inevitably cause a high error in the test structure due to some moisture remaining in the protective structures such as the permeable stone and the permeable membrane at the previous measuring point when testing the next measuring point.

[0067] At the same time, there is no need to set up additional protective mechanisms on the outside of the conductive member 3, such as permeable stone and permeable membrane or stainless steel protective cover, etc. After the water content test of the measuring point is completed, the core hammer at the top can be directly hammered from the specified position to measure the water content of the next point, without inserting a protective mechanism on the outside of the conductive member 3. When the water content is measured at the next measuring point, the protective mechanism is pulled out and then measured. At the same time, the conductive member 3 can directly contact the soil to be tested. Since it can directly contact the soil, the measured water content is the real water content of the soil.

[0068] The connecting portion 801 first passes through the second connecting hole of the insulating sleeve 2, and then continues to enter the first connecting hole 102 of the feeler rod 1, thereby achieving the preliminary fixation of the feeler rod 1 and the connector 8. The pressing portion 802 of the connector 8 is designed to abut against the end face of the insulating sleeve 2 away from the feeler rod 1. When the connector 8 is tightened, the pressing portion 802 will apply pressure to the insulating sleeve 2, further strengthening the connection stability between the feeler rod 1 and the insulating sleeve 2. This structure not only ensures the reliability of the electrical connection, but also enhances the mechanical strength of the overall device. Through the dual effects of the connecting portion 801 and the pressing portion 802 of the connector 8, a firm and stable connection between the feeler rod 1 and the insulating sleeve 2 is achieved, effectively avoiding the risk of loosening or falling off. Ensure good electrical contact between the feeler rod 1 and the insulating sleeve 2, reduce contact resistance, and improve measurement accuracy and signal transmission efficiency. Compared with traditional welding or other fixing methods, this design allows the installation and disassembly of the feeler rod 1 to be completed quickly and conveniently, reducing the difficulty and cost of maintenance. This connection method is suitable for installation requirements under various environmental conditions and can maintain good performance under both static and dynamic conditions. Since the pressing portion 802 of the connector 8 can effectively disperse external stress, the possibility of damage to the probe rod 1 and the insulating sleeve 2 due to uneven force is reduced, which helps to extend the service life of the entire device.

[0069] Furthermore, the insulating sleeve 2 also has a plurality of first wire holes 202, which are connected to the mounting hole 201, and the diameter of the first wire hole 202 is smaller than the diameter of the mounting hole 201; the connector 8 has a first inner cavity 803, and the first inner cavity 803 has a plurality of second wire holes 804, and the aperture of the second wire holes 804 is the same as the aperture of the first wire holes 202, and the second wire holes 804 are connected to the first wire holes 202. The rod body 9 is arranged on the connector 8, and has a second inner cavity, and the first inner cavity 803 is connected to the second inner cavity, and the wire 4 passes through the first wire hole 202, the second wire hole 804, the first inner cavity 803 and the second inner cavity.

[0070] In this embodiment, the design realizes efficient transmission of the wire 4 from the feeler rod 1 to the rod body 9 through multi-level connected wire holes and inner cavities. The insulating sleeve 2 is provided with a plurality of first wire holes 202, which are connected with the mounting hole 201 and are used to guide the wire 4 from the feeler rod 1 into the inside of the insulating sleeve 2. The diameter of the first wire hole 202 is smaller than the diameter of the mounting hole 201 to ensure that the wire 4 will not interfere with other components in the mounting hole 201 during the insertion process. The connector 8 has a first inner cavity 803, which is provided with a plurality of second wire holes 804. The aperture of the second wire hole 804 is the same as that of the first wire hole 202, ensuring that the wire 4 can pass smoothly. The second wire hole 804 is connected with the first wire hole 202, so that the wire 4 can enter the first inner cavity 803 of the connector 8 from the first wire hole 202 of the insulating sleeve 2. The rod body 9 is arranged on the connector 8 and has a second inner cavity, which is connected with the first inner cavity 803 of the connector 8. The wire 4 passes through the first wire hole 202 , the second wire hole 804 , the first inner cavity 803 and the second inner cavity, and finally passes through the second inner cavity of the rod body 9 , completing the transmission path of the entire wire 4 .

[0071] The multi-stage connected wire holes and inner cavity design ensures the smoothness of the wire 4 in the entire transmission path, reduces the risk of wear and breakage of the wire 4 during the transmission process, and improves the reliability of the system. The design of the first wire hole 202 and the second wire hole 804 saves installation space and is suitable for the design requirements of compact equipment. Since the wire 4 is transmitted in multiple closed inner cavities, it is effectively isolated from the influence of the external environment, improves the waterproof and dustproof performance of the system, and is suitable for applications in harsh environments. The wire 4 can be easily installed and maintained through multiple connected wire holes and inner cavities, without the need for complicated wiring steps, reducing the difficulty and cost of installation and maintenance. The multi-stage connected design reduces the signal loss of the wire 4 during the transmission process, improves the efficiency and quality of signal transmission, and ensures the accuracy of measurement and control. The structural design of the connector 8 and the rod body 9 not only ensures the smooth transmission of the wire 4, but also enhances the mechanical strength of the entire system, enabling it to work stably under various working conditions.

[0072] Further, the measurement method is:

[0073] Get the voltage fluctuation threshold Z U Specifically, define an area P and take the following steps in P:

[0074] S01. Prepare a sounding rod 1, wherein the sounding rod 1 has four conductive members 3, which are arranged at intervals and insulated from each other, and are used to contact the soil; the sounding rod 1 also includes: the sounding rod 1; an insulating sleeve 2, which is arranged on the sounding rod 1, and the four conductive members 3 are evenly arranged at intervals on the insulating sleeve 2, and are numbered Q, W, E, and R in the same direction;

[0075] S02. Insert the sounding rod 1 into area P, or remove the soil mass within area P, and insert the sounding rod 1 into the removed soil mass so that the conductive member 3 contacts the soil mass.

[0076] S03. Pass a constant current I through two adjacent conductive members 3, measure the voltage U between the two conductive members 3 that do not have current passed through them, and delimit a voltage fluctuation threshold Z based on the test data of the voltage U. U Specifically: Record multiple sets of fluctuation values Y1 of the voltage U in the stable state of the sounding rod 1; Hammer the sounding rod 1 downward and record the fluctuation value Y2 of the voltage U during the movement of the sounding rod 1, where the maximum value of Y1 < the voltage fluctuation threshold Z. U < the minimum value of Y2.

[0077] Record the number of hammering times L and obtain the soil moisture content ω. Specifically: Delimit one or more sounding areas N on the subgrade, and perform the following steps in the sounding area N:

[0078] S04. Measure the diameter d of the conductive member 3 and the height h of the insulating sleeve 2, and substitute them into the coefficient K calculation formula: K = (1 / d + 1 / h) * 1 / ln2;

[0079] Where K is a calculation coefficient related to the soil type. Through on-site tests and numerical simulation calculations, in this section of the subgrade (mainly silt), its value is preferably taken as 1.85.

[0080] S05. Insert the sounding rod 1 into the sounding area N, or remove the soil mass within the sounding area N, insert the sounding rod 1 into the removed soil mass, and record the number of times N the sounding rod 1 is struck before the conductive member 3 contacts the soil mass.

[0081] S05 - A. Alternately pass a constant current I through the conductive member 3Q and the conductive member 3W. QW Pass a constant current I through the conductive member 3E and the conductive member 3R. ER ;

[0082] S05 - B. When passing a constant current I through the conductive member 3Q and the conductive member 3W, measure the voltage U between the conductive member 3E and the conductive member 3R. QW When passing a constant current I through the conductive member 3E and the conductive member 3R, measure the voltage U between the conductive member 3Q and the conductive member 3W. ER When passing a constant current I through the conductive member 3E and the conductive member 3R, measure the voltage U between the conductive member 3Q and the conductive member 3W. ER When passing a constant current I through the conductive member 3E and the conductive member 3R, measure the voltage U between the conductive member 3Q and the conductive member 3W. QW ;

[0083] S05 - C. Record the number of voltage fluctuations M after the conductive member 3 enters the soil mass. When the fluctuation value Y of the voltage U in the conductive member 3 is greater than the voltage fluctuation threshold Z. UWhen the sounding rod 1 is directly inserted into the soil, so that the conductive member 3 is in direct contact with the soil, then M is the total number of strikes (that is, N is 0). The number of hammer blows is recorded based on this, and the soil density, mechanical properties and other data are determined.

[0084] S06, multiple groups I QW and U ER ,I ER and U QW Substitute the value into the soil conductivity ρ calculation formula: ρ = K (U ER / I QW +U QW / I ER ), calculate and obtain multiple groups of different soil conductivity ρ;

[0085] Among them, S05-A, S05-B, and S05-C occur synchronously with S05;

[0086] S07, putting multiple groups of soils with different electrical conductivities ρ into a drying box for drying to obtain the soil moisture content ω;

[0087] S08. Since the soil moisture content is measured every 15 cm from the reference surface (or ground), the moisture content at this point is recorded as W 15n The soil moisture content at this point measured by the probe rod 1 is W 15n1 , the interference term is denoted as W 15n2 .

[0088] The calculation formula of soil moisture content is: 15n = W 15n1 + W 15n2 , W Hn2 ={(W （Hn1）-X -W Hn1 )+ (W （Hn1）-(X-1) -W Hn1 )+...+(W （Hn1）-1 -W Hn1 )+(W （Hn1）+1 -W Hn1 )+...+(W （Hn1）+X -W Hn1 )} / 2X.

[0089] The moisture content calculation method can basically eliminate the systematic error of the moisture content measurement at the specified location. The calculation method and operation logic of the measured moisture content are encoded to the moisture content measurement device 5 through an encoder. The moisture content measurement device 5 is composed of several single-chip microcomputers containing digital processing chips and electrical signal processing chips and a power supply module, which can realize data collection and processing, and can export test data to a specified location.

[0090] S09. Substitute the soil moisture content ω and soil conductivity ρ into the formula: ω=Aρ B , calculate the fitting parameters A and B;

[0091] The parameters A and B are determined and input into the soil moisture content measuring device 5. The output value of the test system in the test unit is the soil moisture content ω at each position inside the roadbed.

[0092] Further, as a preference, a marking line 10 may be provided on the rod body 9, and each 15 cm and each 30 cm are marked with different colors. The marking line 10 is engraved on the rod body 9, and each 15 cm and each 30 cm are marked with different colors. This allows the constructor to easily identify and measure a specific distance. The marking line 10 every 15 cm uses one color (e.g., red), and the marking line 10 every 30 cm uses another color (e.g., blue). This color distinction helps the constructor to quickly identify different measurement intervals.

[0093] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present invention, which should all be included in the scope of the claims of the present invention.

Claims

1. A combined determination device for water content and soil dynamic penetration characteristics, characterized in that: include: The probe rod (1) has a probe part (101), wherein the probe part (101) is a cone having a cone head part and an end face part; A rod body (9), the rod body (9) being located on one side of the feeler rod (1) and having a diameter smaller than a diameter of the end face portion; An insulating sleeve (2), the insulating sleeve (2) being arranged on the probe rod (1) and located on a side away from the probe portion (101); Conductive members (3), the conductive members (3) having four parts, which are evenly spaced and arranged around the insulating sleeve (2); the main body of the conductive member (3) is located inside the insulating sleeve (2), and one end of the conductive member (3) is used to contact the soil; Conductors (4), the conductors (4) comprising four conductors, one end of each conductor (4) being electrically connected to one of the conductive members (3); A moisture content measuring device (5), the other end of the wire (4) being electrically connected to the moisture content measuring device (5); The four conductive members (3) are numbered Q, W, E, and R in sequence in the same direction, and a constant current I is alternately generated to the conductive member (3) Q and the conductive member (3) W. QW , measure the voltage U between the conductive part (3) E and the conductive part (3) R ER , a constant current I is generated to the conductive member (3) E and the conductive member (3) R ER , measure the voltage U between the conductive part (3) Q and the conductive part (3) W QW , multiple groups I QW and U ER ,I ER and U QW Substitute the value into the soil conductivity ρ calculation formula: ρ = K (U ER / I QW +U QW / I ER ), calculate and obtain multiple groups of different soil conductivity ρ; Wherein K=(1 / r+1 / h)*1 / ln2, r is the diameter of the conductive part 3, and h is the height of the insulating sleeve 2.

2. The combined determination device for water content and soil dynamic penetration characteristics according to claim 1 is characterized in that: The feeler rod (1) has a first slope (6) arranged obliquely, and the insulating sleeve (2) has a second slope (7) arranged obliquely, the first slope (6) and the second slope (7) are parallel to each other, and the end of the first slope (6) close to the axis of the feeler rod (1) is higher or lower than the end far from the axis of the feeler rod (1).

3. A combined determination device for water content and soil dynamic penetration characteristics according to claim 2, characterized in that: The inclination angle of the first slope surface (6) is α, 0.3≤tanα≤0.

6.

4. The combined determination device for water content and soil dynamic penetration characteristics according to claim 1 is characterized in that: The insulating sleeve (2) has a plurality of mounting holes (201) for mounting the conductive member (3); the mounting holes (201) have internal threads, the conductive member (3) has external threads, and the conductive member (3) is threadedly connected to the mounting holes (201); The feeler rod (1) has a first connection hole (102), and the insulating sleeve (2) has a second connection hole (203); Also includes: A connecting member (8), wherein the connecting member (8) has a connecting portion (801), wherein the connecting portion (801) passes through the second connecting hole (203), enters the first connecting hole (102), and is connected to the feeler rod (1).

5. The combined determination device for water content and soil dynamic penetration characteristics according to claim 4 is characterized in that: The connecting piece (8) has a pressing portion (802), and the pressing portion (802) abuts against the end surface of the insulating sleeve (2) away from the feeler rod (1).

6. The combined determination device for water content and soil dynamic penetration characteristics according to claim 5 is characterized in that: The insulating sleeve (2) further comprises a plurality of first wire holes (202), wherein the first wire holes (202) are in communication with the mounting hole (201), and the diameter of the first wire holes (202) is smaller than the diameter of the mounting hole (201); The connecting member (8) has a first inner cavity (803), the first inner cavity (803) has a plurality of second wire holes (804), the aperture of the second wire holes (804) is the same as the aperture of the first wire holes (202), and the second wire holes (804) are connected to the first wire holes (202); The rod body (9) is arranged on the connecting member (8) and has a second inner cavity. The first inner cavity (803) is connected to the second inner cavity. The wire (4) passes through the first wire hole (202), the second wire hole (804), the first inner cavity (803) and the second inner cavity.

7. A combined determination device for water content and soil dynamic penetration characteristics according to claim 6, characterized in that: Put multiple groups of soils with different electrical conductivities ρ into a drying box for drying, and obtain the soil moisture content ω; The soil moisture content at a distance of H*n from the ground is W Hn The measured soil moisture content at this point is W Hn1 , the interference term is denoted as W Hn2 ; Substitute the soil moisture content W into the correction calculation formula: W Hn = W Hn1 + W Hn2 .

8. The combined determination device for water content and soil dynamic penetration characteristics according to claim 7 is characterized in that: W Hn2 is the soil moisture content and W measured by the front X-stroke and the back X-stroke at the H*n position Hn1 The mean of the differences is: IN Hn2 ={(In （Hn1）-X - IN Hn1 )+ (In （Hn1）-(X-1) - IN Hn1 )+...+(In （Hn1）-1 - IN Hn1 )+(In （Hn1）+1 - IN Hn1 )+...+(In （Hn1）+X - IN Hn1 )} / 2X。

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