Device and method for measuring soil state under water level change condition

Abstract

The invention relates to the technical field of geotechnical engineering testing, in particular to a device and a method for measuring a soil body state under a water level change condition, and mainly solves the technical problem that existing stratum soil body measurement cannot be suitable for soil body state measurement under the water level change condition. The device comprises a three-dimensional right-angle base and a seven-face cover body, an industrial control board and a soil humidity sensor are arranged in the three-dimensional right-angle base, and six soil pressure boxes and a pore water pressure sensor are arranged on the seven-face cover body. The sensor can comprehensively detect the total stress state of the soil body, then calculates the effective stress state according to the total stress state, and is high in result accuracy; moreover, the sensor not only can be suitable for detecting the effective stress state of the soil body in a saturated state, but also can be suitable for detecting the effective stress state of the soil body in an unsaturated state, so that the sensor can be suitable for detecting the effective stress state of the soil body in an underground water level change scene.

Description

Technical Field

[0001] The present invention relates to the technical field of geotechnical engineering testing, and in particular to a device and method for measuring soil state under water level fluctuation conditions. Background Art

[0002] The change of groundwater level will cause the soil in the formation to transform between saturated and unsaturated states, thus inducing a series of geotechnical engineering problems. Determining the effective stress state of the soil in the formation is the premise for revealing the disturbance mechanism of the mechanical response of the formation induced by groundwater level change.

[0003] The soil in the stratum is a porous medium material composed of soil particles. The effective stress is a basic constitutive variable that controls the mechanical behavior of the soil, and the effective stress is related to the saturation, pore water pressure and total stress of the soil. In the existing technology, the effective stress state of the soil can generally only be detected in the saturated state (there is only water but no air in the pores of the soil), but when the groundwater level changes, the volume ratio of water to air in the pores of the soil will change, that is, the saturation will change, so it is not suitable for measuring the state of the soil under the condition of water level changes. Summary of the invention

[0004] In order to overcome the technical defect that the existing stratum soil measurement is not applicable to the measurement of soil state under water level fluctuation conditions, the present invention provides a measuring device and a measuring method for soil state under water level fluctuation conditions.

[0005] The present invention provides a device for measuring soil state under water level fluctuation conditions, comprising:

[0006] A three-dimensional right-angle base, comprising three mounting plates that are perpendicular to each other, wherein the first mounting plate is provided with a threading hole to serve as a threading plate, the second mounting plate is provided with a first through hole to serve as a mounting side plate, and the third mounting plate serves as a mounting bottom plate and has a mounting groove on its upper surface;

[0007] A seven-sided mask body, comprising three square plates, three rectangular plates and one equilateral triangular plate, the three square plates are respectively parallel to the three mounting plates and a group of adjacent side walls of each square plate are respectively fixed on two perpendicular mounting plates, a mounting space is formed between every two perpendicular squares, the three rectangular plates are respectively located in the three mounting spaces, a group of opposite side walls of each rectangular plate are respectively connected to the corresponding two square plates and each rectangular plate forms an angle of 45° with the corresponding square plate, the equilateral triangular plate is connected in the area surrounded by the three rectangular plates, the square plate and the rectangular plate are both provided with a second through hole, and the equilateral triangular plate is provided with a third through hole;

[0008] A soil moisture sensor, which is embedded in the first through hole and has a probe extending outward from the mounting side plate, and the soil moisture sensor is used to collect the volume moisture content of the soil;

[0009] There are six earth pressure boxes, which are respectively embedded in the six second through holes, and the earth pressure boxes are used to collect the positive pressure of the corresponding surface;

[0010] A pore water pressure sensor, which is embedded in the third through hole and is used to collect the pore water pressure value of the soil;

[0011] An industrial control board is embedded in the installation groove. The industrial control board is provided with eight electrical signal receiving terminals and one digital signal output terminal. The eight electrical signal receiving terminals are respectively connected to the soil moisture sensor, six soil pressure boxes and the pore water pressure sensor through cables. The digital signal output terminal is connected to a cable and is led out from the threading hole.

[0012] Optionally, the mounting base plate and the threading plate are integrally formed to form an L-shaped plate.

[0013] Optionally, the mounting side plate and the threading plate are both pentagonal plates so as to be adaptable to the seven-sided cover body.

[0014] Optionally, the soil pressure box and the pore water pressure sensor are both silicon piezoresistive pressure sensors.

[0015] Optionally, the load-bearing surface of the earth pressure box is convex to the outer surface of the square plate or the outer surface of the rectangular plate.

[0016] Optionally, the permeable surface of the pore water pressure sensor is concave inside the outer surface of the equilateral triangle plate.

[0017] The measuring method provided by the present invention comprises the following steps:

[0018] S1. Connect the industrial control board to the data processor via a cable;

[0019] S2. Input the porosity ratio e and the hydraulic parameter a of the soil at the intended measurement location into the monitoring software. d and m;

[0020] S3. Place the measuring device in the air for data collection, and adjust the sensor feedback according to the collected values ​​to complete the initialization process;

[0021] S4. Prepare a model formation and place the measuring device at the intended measurement position of the model formation so that the installation base is perpendicular to the gravity direction, and then collect data. The data processor calculates the effective stress state based on the collected values, saves and displays them in real time;

[0022] S5. Inject water or drain water into the model formation and collect data simultaneously. The data processor calculates the effective stress state based on the collected values, saves and displays them in real time.

[0023] Optionally, the data processor calculates the effective stress state by the following algorithm:

[0024] 1) Calculate the total stress state at a point in the soil mass according to the following formula: :

[0025] ;

[0026] in, , and They represent the normal stress collected by the earth pressure boxes located on the three square plates, , and They represent the normal stresses collected by the earth pressure cells located on the three rectangular plates;

[0027] 2) Based on the pore water pressure value collected by the pore water pressure sensor Saturation determination: If , the soil is in a saturated state; if , the soil is in an unsaturated state;

[0028] 3) Calculate the effective stress state :

[0029] If the soil is saturated, Calculated according to the following formula:

[0030] ;

[0031] If the soil is unsaturated, Calculated according to the following formula:

[0032] ;

[0033] in, Indicates the volumetric moisture content of the soil collected by the soil moisture sensor.

[0034] The technical solution provided by the present invention has the following advantages compared with the prior art:

[0035] The measuring device of soil state under water level fluctuation conditions provided by the present invention can collect the normal stress of a point in the soil on six surfaces based on a dual orthogonal coordinate system through six soil pressure boxes, so that the shear stress of the point on three surfaces based on a three-dimensional rectangular coordinate system can be obtained by calculation, and then the total stress state at the point can be fully characterized; the saturation of the soil can be judged by a pore water pressure sensor, and then the effective stress state under saturation can be calculated according to the total stress state combined with the pore water pressure value collected by the pore water pressure sensor, and the effective stress state under unsaturation can be calculated according to the total stress state combined with the volume moisture content of the soil collected by the soil moisture sensor. The sensor can fully detect the total stress state of the soil, and then calculate the effective stress state according to the total stress state, and the result is highly accurate; and the sensor can be applied not only to the detection of effective stress state of soil under saturation, but also to the detection of effective stress state under unsaturated state, so it can be applied to the detection of effective stress state of soil under groundwater level fluctuation scenarios.

[0036] The measuring method provided by the present invention has the aforementioned advantages because it adopts the aforementioned sensor. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the invention and, together with the description, serve to explain the principles of the invention.

[0038] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0039] Figure 1 A schematic diagram showing the overall structure of a measuring device in an embodiment of the present invention;

[0040] Figure 2 It shows the assembly diagram of the three-dimensional right-angle base and its auxiliary structures in the embodiment of the present invention;

[0041] Figure 3 An exploded view showing a three-dimensional right-angle base according to an embodiment of the present invention;

[0042] Figure 4 An exploded view of a seven-sided cover body and its accessory structures in an embodiment of the present invention is shown;

[0043] Figure 5 A schematic diagram showing the use status of the measuring device in the embodiment of the present invention.

[0044] In the figure:

[0045] 1. Three-dimensional right-angle base; 11. Threading plate; 111. Threading hole; 12. Mounting side plate; 121. First through hole; 13. Mounting bottom plate; 131. Mounting slot; 2. Seven-sided cover; 21. Square plate; 22. Rectangular plate; 23. Regular triangle plate; 24. Second through hole; 25. Third through hole; 3. Soil moisture sensor; 31. Probe; 4. Soil pressure box; 41. Force surface; 5. Pore water pressure sensor; 51. Permeable surface; 6. Industrial control board; 61. Electrical signal receiving end; 62. Digital signal output end; 7. Data processor. DETAILED DESCRIPTION

[0046] In order to more clearly understand the above-mentioned objectives, features and advantages of the present invention, the scheme of the present invention will be further described below. It should be noted that the embodiments of the present invention and the features in the embodiments can be combined with each other without conflict.

[0047] In the description, it should be noted that the terms “first” and “second” are only used for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0048] In the following description, many specific details are set forth to facilitate a full understanding of the present invention, but the present invention may also be implemented in other ways different from those described herein; it is obvious that the embodiments in the specification are only part of the embodiments of the present invention, rather than all of the embodiments.

[0049] Combine the following Figures 1 to 5 The specific embodiments of the present invention are described in detail.

[0050] Example 1

[0051] This embodiment provides a device for measuring soil state under water level fluctuation conditions, including a three-dimensional right-angle base 1, a seven-sided mask 2, a soil moisture sensor 3, an earth pressure box 4, a pore water pressure sensor 5 and an industrial control board 6.

[0052] Among them, the three-dimensional right-angle base 1 includes three mounting plates that are perpendicular to each other, and the first mounting plate is provided with a threading hole 111 to serve as a threading plate 11, the second mounting plate is provided with a first through hole 121 to serve as a mounting side plate 12, and the third mounting plate serves as a mounting bottom plate 13 and has a mounting groove 131 on the upper surface.

[0053] Specifically, the mounting base plate 13 and the threading plate 11 of this embodiment are integrally formed to form an L-shaped plate. In other embodiments, the mounting base plate 13 and the threading plate 11 can also be provided separately, and can also be fixedly connected to form an L-shaped plate during assembly.

[0054] Specifically, the mounting side plate 12 and the threading plate 11 are both pentagonal plates so as to be able to fit the seven-sided cover body 2 .

[0055] It should be noted that when the side panels 12 , the threading plate 11 and the bottom panel 13 are connected, sealant is used to seal the joints to prevent water from entering the housing and damaging the industrial control board 6 .

[0056] Among them, the seven-sided mask body 2 includes three square plates 21, three rectangular plates 22 and an equilateral triangular plate 23, the three square plates 21 are respectively parallel to the three mounting plates and a group of adjacent side walls of each square plate 21 are respectively fixed on two perpendicular mounting plates, an installation space is formed between every two perpendicular squares, the three rectangular plates 22 are respectively located in the three installation spaces, a group of relative side walls of each rectangular plate 22 are respectively connected to the corresponding two square plates 21 and each rectangular plate 22 is at an angle of 45° with the corresponding square plate 21, the equilateral triangular plate 23 is connected in the area surrounded by the three rectangular plates 22, the square plates 21 and the rectangular plates 22 are both provided with a second through hole 24, and the equilateral triangular plate is provided with a third through hole 25.

[0057] It is easy to understand that the three square plates 21 and the three rectangular plates 22 all form three surfaces based on a three-dimensional rectangular coordinate system, and the six plates together form six surfaces based on a dual orthogonal coordinate system.

[0058] It should be noted that when the seven-sided cover body 2 is spliced ​​internally or spliced ​​with the three-dimensional right-angle base 1, a sealant needs to be used to seal the joints to prevent water from entering the shell and damaging the industrial control board 6.

[0059] The soil moisture sensor 3 is embedded in the first through hole 121 and the probe 31 extends outward from the mounting side plate 12 . The soil moisture sensor 3 is used to collect the volume moisture content of the soil.

[0060] Specifically, the soil moisture sensor 3 is a FDR (frequency domain reflectometry) type sensor, which has the advantages of being simple and safe, fast and accurate, fixed-point continuous, automated, with a wide range and less calibration.

[0061] It should be noted that after the soil moisture sensor 3 is embedded in the first through hole 121 , a sealant needs to be used to seal the joint to prevent water from entering the housing and damaging the industrial control board 6 .

[0062] There are six earth pressure boxes 4 which are respectively embedded in the six second through holes 24 . The earth pressure boxes 4 are used to collect the positive pressure of the corresponding surface.

[0063] Specifically, the soil pressure box 4 is a silicon piezoresistive pressure sensor, which has the advantages of no initial value, high precision, high sensitivity and strong stability.

[0064] Specifically, the force-bearing surface 41 of the earth pressure box is convex from the outer surface of the square plate 21 or the outer surface of the rectangular plate 22 to ensure the accuracy of the detection.

[0065] It should be noted that after the earth pressure box 4 is embedded in the second through hole 24 , a sealant needs to be used to seal the joint to prevent water from entering the shell and damaging the industrial control board 6 .

[0066] The pore water pressure sensor 5 is embedded in the third through hole 25 and is used to collect the pore water pressure value of the soil.

[0067] Specifically, the pore water pressure sensor 5 is also a silicon piezoresistive pressure sensor.

[0068] Specifically, the water permeable surface 51 of the pore water pressure sensor 5 is recessed into the outer surface of the regular triangle plate 23 to prevent the water permeable surface 51 from being damaged.

[0069] It should be noted that after the pore water pressure sensor 5 is embedded in the third through hole 25 , a sealant needs to be used to seal the joint to prevent water from entering the housing and damaging the industrial control board 6 .

[0070] Among them, the industrial control board 6 is embedded in the installation groove 131, and the industrial control board 6 is provided with eight electrical signal receiving terminals 61 and one digital signal output terminal 62. The eight electrical signal receiving terminals 61 are respectively connected to the soil moisture sensor 3, six soil pressure boxes 4 and the pore water pressure sensor 5 through cables, and the digital signal output terminal 62 is connected to the cable and led out from the threading hole 111.

[0071] It is easy to understand that the main function of the industrial control board 6 is to receive the physical quantity signals collected by the eight sensors and convert the physical quantity signals into digital signals and output them from the digital signal output terminal 62 .

[0072] Specifically, the industrial control board 6 is adhered in the installation groove 131 by means of sealant.

[0073] It should be noted that after the cables are led out from the threading holes 111 , sealants are required to seal the joints to prevent water from entering the housing and damaging the industrial control board 6 .

[0074] The assembly process of the measuring device of this embodiment is as follows:

[0075] The first step is to stick the industrial control board 6 into the mounting groove 131 of the mounting base plate 13 with a sealant, and lead the cable of the digital signal output terminal 62 out from the threading hole 111;

[0076] In the second step, the soil moisture sensor 3 is fixed in the first through hole 121 by means of sealant, and the probe 31 is extended outward from the mounting side plate 12, and then the mounting side plate 12 is fixed to the L-shaped plate by means of sealant, and finally the cable of the soil moisture sensor 3 is connected to the electrical signal receiving end 61 corresponding to the industrial control board 6;

[0077] The third step is to fix the six earth pressure boxes 4 in the second through holes 24 by means of sealant, and make the force-bearing surface 41 protrude outward from the seven-sided cover body 2, and then fix the seven-sided cover body 2 without the regular triangle plate 23 installed on the L-shaped plate and the mounting side plate 12 by means of sealant, and finally connect the cable of the earth pressure box 4 to the electrical signal receiving end 61 corresponding to the industrial control board 6;

[0078] In the fourth step, the pore water pressure sensor 5 is fixed in the third through hole 25 by means of sealant, and the permeable surface 51 is recessed in the equilateral triangle plate 23, and then the cable of the pore water pressure sensor 5 is connected to the electrical signal receiving end 61 corresponding to the industrial control board 6, and finally the equilateral triangle plate 23 is fixed in the reserved position of the seven-sided cover body 2 by means of sealant.

[0079] The data processor 7 is connected to the digital signal output terminal 62 of the industrial control board 6, and the data processor 7 is used to calculate the effective stress state of the soil according to the six normal pressures, the pore water pressure value and the volume water content.

[0080] The working principle of the measuring device of this embodiment is as follows:

[0081] Eight values ​​can be collected through eight sensors: six normal stresses, one pore water pressure and one volumetric water content; the three-dimensional total stress state at a certain point in the soil can be calculated based on the six normal stresses; the saturation of the soil can be determined based on the pore water pressure, and then the effective stress state in the saturated state can be calculated based on the total stress state combined with the pore water pressure value, and the effective stress state in the unsaturated state can be calculated based on the total stress state combined with the volumetric water content, so that the device can be used in water level change scenarios where the saturation changes.

[0082] Example 2

[0083] This embodiment provides a measurement method, comprising the following steps:

[0084] S1. Connect the industrial control board 6 to the data processor 7 via a cable;

[0085] It is easy to understand that the data processor 7 needs to be integrated with monitoring software and calculation programs to be able to analyze and process the digital signal output by the industrial control board 6;

[0086] S2. Input the porosity ratio e and the hydraulic parameter a of the soil at the intended measurement location into the monitoring software. d and m;

[0087] S3. The measuring device described in the embodiment is placed in the air for data collection, and the sensor feedback is adjusted according to the collected value to complete the initialization process;

[0088] It should be noted that, for the silicon piezoresistive pressure sensor used in Example 1, its initial value is small, and this step can be omitted; however, if a strain gauge pressure sensor is used, the sensor needs to be zeroed in this step to ensure the accuracy of subsequent measurements;

[0089] S4. Prepare a model formation, and place the measuring device described in Example 1 at the intended measurement position of the model formation, so that the mounting base 13 is perpendicular to the direction of gravity, and then collect data, the data processor 7 calculates the effective stress state according to the collected values, saves and displays it in real time;

[0090] It is easy to understand that this step is mainly used to measure the initial state of the soil mass;

[0091] S5. Inject water or drain water into the model formation, collect data simultaneously, and the data processor 7 calculates the effective stress state according to the collected values, saves and displays them in real time;

[0092] It is easy to understand that this step is mainly used to measure the state change of the stratum soil during the water injection process or the drainage process to simulate the state change of the soil under the water level change scenario.

[0093] Specifically, the data processor calculates the effective stress state through the following algorithm:

[0094] 1) Calculate the total stress state at a point in the soil mass according to the following formula: :

[0095] ;

[0096] in, , and They represent the normal stress collected by the earth pressure cells 4 located on the three square plates 21, , and They respectively represent the normal stresses collected by the earth pressure cells 4 located on the three rectangular plates 22;

[0097] 2) Based on the pore water pressure value collected by pore water pressure sensor 5 Saturation determination: If , the soil is in a saturated state; if , the soil is in an unsaturated state;

[0098] 3) Calculate the effective stress state :

[0099] If the soil is saturated, Calculated according to the following formula:

[0100] ;

[0101] If the soil is unsaturated, Calculated according to the following formula:

[0102] ;

[0103] in, It represents the volumetric moisture content of the soil collected by the soil moisture sensor 3.

[0104] More specifically, the total stress state is The calculation formula is derived:

[0105] First, according to the Cauchy formula, the normal stress on the inclined plane can be expressed as:

[0106] ;

[0107] in, represents direction cosines, for For ,for For ,for For , substituting into the above formula, we can get:

[0108] ;

[0109] So it can be deduced that:

[0110] ;

[0111] The total stress state can be obtained .

[0112] More specifically, the effective stress state in the unsaturated state is The calculation formula is derived:

[0113] First, we know e and a d , m and θ, and , , , V represents the total volume of the soil at a certain point, V V represents the pore volume of the soil at that point, V S It represents the volume of soil particles at that point in the soil mass;

[0114] Saturation The expression is:

[0115] ;

[0116] Saturation The relationship between it and matrix suction s is:

[0117] ;

[0118] The above formula is available Express s, that is:

[0119] ;

[0120] but:

[0121] ;

[0122] The effective stress state under unsaturated condition can be obtained .

[0123] The above is only a specific implementation of the present invention, which enables those skilled in the art to understand or implement the present invention. Although detailed descriptions are given with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions recorded in the aforementioned embodiments, or replace some or all of the technical features therein by equivalents; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments, and they should all be covered by the protection scope of the claims.

Claims

1. A device for measuring soil state under water level fluctuation conditions, characterized in that: include: A three-dimensional right-angle base (1) comprising three mounting plates arranged perpendicular to each other, wherein the first mounting plate is provided with a threading hole (111) to serve as a threading plate (11), the second mounting plate is provided with a first through hole (121) to serve as a mounting side plate (12), and the third mounting plate serves as a mounting bottom plate (13) and has a mounting groove (131) on its upper surface; A seven-sided mask body (2), comprising three square plates (21), three rectangular plates (22) and an equilateral triangular plate (23), the three square plates (21) being parallel to the three mounting plates respectively and a group of adjacent side walls of each square plate (21) being fixed to two perpendicular mounting plates respectively, a mounting space being formed between every two perpendicular squares, the three rectangular plates (22) being located in the three mounting spaces respectively, a group of opposite side walls of each rectangular plate (22) being connected to the corresponding two square plates (21) respectively and each rectangular plate (22) forming an angle of 45° with the corresponding square plate (21), the equilateral triangular plate (23) being connected to the area enclosed by the three rectangular plates (22), the square plate (21) and the rectangular plate (22) both being provided with a second through hole (24), and the equilateral triangular plate being provided with a third through hole (25); A soil moisture sensor (3), which is embedded in the first through hole (121) and the probe (31) extends outward from the mounting side plate (12), and the soil moisture sensor (3) is used to collect the volume moisture content of the soil; Earth pressure boxes (4), six of which are provided and respectively embedded in the six second through holes (24), the earth pressure boxes (4) being used to collect the positive pressure of the corresponding surface; A pore water pressure sensor (5), which is embedded in the third through hole (25) and is used to collect the pore water pressure value of the soil; An industrial control board (6) is embedded in the mounting groove (131), and is provided with eight electrical signal receiving terminals (61) and a digital signal output terminal (62). The eight electrical signal receiving terminals (61) are respectively connected to a soil moisture sensor (3), six soil pressure boxes (4), and a pore water pressure sensor (5) via cables, and the digital signal output terminal (62) is connected to a cable and is led out from the threading hole (111) for connection to a data processor (7).

2. The device for measuring soil state under water level fluctuation conditions according to claim 1, characterized in that: The mounting base plate (13) and the threading plate (11) are integrally formed to form an L-shaped plate.

3. The device for measuring soil state under water level fluctuation conditions according to claim 2, characterized in that: The mounting side plate (12) and the threading plate (11) are both pentagonal plates so as to be compatible with the seven-sided cover body (2).

4. The device for measuring soil state under water level fluctuation conditions according to claim 1, characterized in that: The soil pressure box (4) and the pore water pressure sensor (5) are both silicon piezoresistive pressure sensors.

5. The device for measuring soil state under water level fluctuation conditions according to any one of claims 1 to 4, characterized in that: The force-bearing surface (41) of the earth pressure box is convex from the outer surface of the square plate (21) or the outer surface of the rectangular plate (22).

6. The device for measuring soil state under water level fluctuation conditions according to any one of claims 1 to 4, characterized in that: The water permeable surface (51) of the pore water pressure sensor (5) is recessed into the outer surface of the equilateral triangle plate (23).

7. A method for measuring soil state under water level fluctuation conditions using a measuring device as claimed in any one of claims 1 to 6, characterized in that: The steps include: S1. Connecting the industrial control board (6) to the data processor (7) via a cable; S2. Input the porosity ratio e and the hydraulic parameter a of the soil at the intended measurement location into the monitoring software. d and m; S3. Place the measuring device in the air to collect data, and adjust the sensor feedback according to the collected value to complete the initialization process; S4. Prepare a model formation and place the measuring device at the intended measuring position of the model formation so that the mounting base (13) is perpendicular to the gravity direction, and then collect data. The data processor (7) calculates the effective stress state based on the collected values, saves and displays them in real time; S5. The model formation is injected with water or drained, and data is collected simultaneously. The data processor (7) calculates the effective stress state based on the collected values, and saves and displays them in real time.

8. The measuring method according to claim 7, characterized in that: The data processor (7) calculates the effective stress state by the following algorithm: 1) Calculate the total stress state at a point in the soil mass according to the following formula: : ； in, , and They represent the normal stress collected by the earth pressure boxes (4) located on the three square plates (21), , and Respectively represent the normal stress collected by the earth pressure boxes (4) located on the three rectangular plates (22); 2) Based on the pore water pressure value collected by the pore water pressure sensor (5) Saturation determination: If , the soil is in a saturated state; if , the soil is in an unsaturated state; 3) Calculate the effective stress state : If the soil is saturated, Calculated according to the following formula: ； If the soil is unsaturated, Calculated according to the following formula: ； in, It represents the volumetric moisture content of the soil collected by the soil moisture sensor (3).

Images