Measurement device and measurement method for soil state under water level change conditions

Abstract

The present invention relates to the technical field of geotechnical engineering testing, and specifically relates to a measuring device and a measuring method for the state of soil under water level change conditions, mainly solving the technical problem that the existing measurement of stratum soil cannot be applied to the measurement of the state of soil under water level change conditions. The device includes a three-dimensional right-angle base and a seven-sided mask body. An industrial control board and a soil humidity sensor are arranged inside the three-dimensional right-angle base, and six earth pressure cells and a pore water pressure sensor are arranged on the seven-sided mask body. This sensor can comprehensively detect the total stress state of the soil body, and then calculate the effective stress state according to the total stress state, with high result accuracy; moreover, this sensor can not only be applied to the detection of the effective stress state of the soil body in the saturated state, but also be applied to the detection of the effective stress state of the soil body in the unsaturated state, so it can be applied to the detection of the effective stress state of the soil body in the scenario of underground water level change.

Description

Technical Field

[0001] The present invention relates to the technical field of geotechnical engineering testing, and particularly relates to a measuring device and a measuring method for the state of soil mass under the condition of water level change. Background Art

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

[0003] The stratum soil 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 mass, and the effective stress is related to the saturation degree, pore water pressure and total stress of the soil mass. In the prior art, generally only the effective stress state of the soil mass in the saturated state (only water and no air in the soil pores) can be detected. However, when the underground water level changes, the volume ratio of water to air in the soil pores will change, that is, the saturation degree will change. Therefore, it is not applicable to the measurement of the state of the soil mass under the condition of water level change. Summary of the Invention

[0004] In order to overcome the technical defect that the existing measurement of the stratum soil mass cannot be applied to the measurement of the state of the soil mass under the condition of water level change, the present invention provides a measuring device and a measuring method for the state of the soil mass under the condition of water level change.

[0005] The measuring device for the state of the soil mass under the condition of water level change provided by the present invention includes:

[0006] A three-dimensional right-angle base, which includes three mounting plates perpendicular to each other in pairs. The first mounting plate is provided with a wire passing hole to serve as a wire passing 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 an installation groove is opened on the upper surface;

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

[0008] A soil moisture sensor is embedded in the first through hole and the probe extends outside the mounting side plate. The soil moisture sensor is used to collect the volumetric water content of the soil body;

[0009] Six earth pressure cells are provided and are respectively embedded in six second through holes. The earth pressure cells are used to collect the normal pressure of the corresponding surface;

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

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

[0012] Optionally, the installation bottom plate and the wire passing plate are integrally formed into an L-shaped plate.

[0013] Optionally, the installation side plate and the wire passing plate are both pentagonal plates to be adapted to the seven-sided mask body.

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

[0015] Optionally, the stress-bearing surface of the earth pressure cell protrudes from the outer surface of the square plate or the outer surface of the rectangular plate.

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

[0017] The measurement method provided by the present invention includes the following steps:

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

[0019] S2. Input the void ratio e and the hydraulic parameters a d and m of the soil body at the position to be measured in the monitoring software;

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

[0021] S4. Prepare a model formation, place the measuring device at the position to be measured in the model formation, make the installation bottom plate perpendicular to the direction of gravity, and then conduct data collection. The data processor calculates the effective stress state according to the collected value, saves and displays it in real time;

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

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

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

[0025] ;

[0026] Wherein, , and respectively represent the normal stresses collected by the earth pressure cells located on three square plates, , and respectively represent the normal stresses collected by the earth pressure cells located on three rectangular plates;

[0027] 2) Judge the saturation degree according to the pore water pressure value collected by the pore water pressure sensor: If , the soil mass is in a saturated state; if , the soil mass is in an unsaturated state;

[0028] 3) Calculate the effective stress state :

[0029] If the soil mass is in a saturated state, calculate according to the following formula:

[0030] ;

[0031] If the soil mass is in an unsaturated state, calculate according to the following formula:

[0032] ;

[0033] Wherein, represents the volumetric water content of the soil mass 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 for the state of soil mass under water level change provided by the present invention can collect the normal stresses on six surfaces of a point in the soil mass based on a double orthogonal coordinate system through six earth pressure cells, so that the shear stresses on three surfaces of the point based on a three-dimensional rectangular coordinate system can be obtained through calculation, and then the total stress state of the point can be comprehensively characterized; the saturation degree of the soil mass can be judged through a pore water pressure sensor, and then the effective stress state under the saturated state 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 the unsaturated state can be calculated according to the total stress state combined with the volumetric water content of the soil mass collected by the soil moisture sensor. This sensor can comprehensively detect the total stress state of the soil mass, and then calculate the effective stress state according to the total stress state, and the result has high accuracy; moreover, this sensor can not only be applied to the detection of the effective stress state of the soil mass under the saturated state, but also be applied to the detection of the effective stress state under the unsaturated state, so it can be applied to the detection of the effective stress state of the soil mass under the scenario of underground water level change.

[0036] Since the measurement method provided by the present invention uses the aforementioned sensor, it has the aforementioned advantages. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] The accompanying drawings here are incorporated into the specification and form a part of this specification, showing embodiments consistent with the present invention, and are used together with the specification to explain the principles of the present invention.

[0038] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, for those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0039] Figure 1 It shows the overall structural schematic diagram of the measuring device in the embodiment of the present invention;

[0040] Figure 2 It shows the assembly drawing of the three-dimensional rectangular base and its attached structures in the embodiment of the present invention;

[0041] Figure 3 It shows the exploded view of the three-dimensional rectangular base in the embodiment of the present invention;

[0042] Figure 4 It shows the exploded view of the seven-face mask body and its attached structures in the embodiment of the present invention;

[0043] Figure 5 It shows the schematic diagram of the usage state of the measuring device in the embodiment of the present invention.

[0044] In the figure:

[0045] 1. Three-dimensional right-angle base; 11. Threading board; 111. Threading hole; 12. Installation side plate; 121. First through hole; 13. Installation bottom plate; 131. Installation groove; 2. Seven-sided mask body; 21. Square plate; 22. Rectangular plate; 23. Equilateral triangle plate; 24. Second through hole; 25. Third through hole; 3. Soil moisture sensor; 31. Probe; 4. Earth pressure cell; 41. Stress 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 implementation mode

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

[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 in order to fully understand the present invention, but the present invention can also be implemented in other ways different from those described herein; obviously, the embodiments in the specification are only part of the embodiments of the present invention, rather than all of the embodiments.

[0049] The following combines Figures 1 to 5 to describe in detail the specific embodiments of the present invention.

[0050] Embodiment 1

[0051] This embodiment provides a measuring device for the state of soil mass under water level change conditions, including a three-dimensional right-angle base 1, a seven-sided mask body 2, a soil moisture sensor 3, an earth pressure cell 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 in pairs. The first mounting plate is provided with a threading hole 111 to serve as a threading board 11, the second mounting plate is provided with a first through hole 121 to serve as an installation side plate 12, and the third mounting plate serves as an installation bottom plate 13 and an installation groove 131 is provided on the upper surface.

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

[0054] Specifically, both the installation side plate 12 and the threading board 11 are pentagonal plates to be adapted to the seven-sided mask body 2.

[0055] It should be noted that when the installation side plate 12, the wire threading plate 11 and the installation bottom plate 13 are spliced, a sealant should be 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 triangle plate 23. The three square plates 21 are respectively parallel to the three installation plates, and a set of adjacent side walls of each square plate 21 are respectively fixed on two perpendicular installation plates. An installation space is formed between every two perpendicular square plates. The three rectangular plates 22 are respectively located in the three installation spaces. A set of opposite side walls of each rectangular plate 22 are respectively connected to the corresponding two square plates 21, and each rectangular plate 22 forms a 45° angle with the corresponding square plate 21. The equilateral triangle plate 23 is connected within the area enclosed by the three rectangular plates 22. The square plates 21 and the rectangular plates 22 are both provided with second through holes 24, and the equilateral triangle plate 23 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 both form three faces based on the three-dimensional rectangular coordinate system, and the six plates together form six faces based on the bi-orthogonal coordinate system.

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

[0059] Among them, the soil moisture sensor 3 is embedded in the first through hole 121 and the probe 31 extends outside the installation side plate 12. The soil moisture sensor 3 is used to collect the volumetric water content of the soil mass.

[0060] Specifically, the soil moisture sensor 3 is an FDR (Frequency Domain Reflectometry) type sensor, which has the advantages of simplicity, safety, rapidity, accuracy, fixed-point continuity, automation, wide range, and few calibrations.

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

[0062] Among them, six soil pressure cells 4 are respectively embedded in the six second through holes 24, and the soil pressure cells 4 are used to collect the normal pressure of the corresponding surface.

[0063] Specifically, the soil pressure cell 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 stress surface 41 of the soil pressure cell 4 protrudes from the outer surface of the square plate 21 or the outer surface of the rectangular plate 22 to ensure the accuracy of detection.

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

[0066] Among them, 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 mass.

[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 concave with respect to the outer surface of the equilateral 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, the joint needs to be sealed with sealant 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. The industrial control board 6 is provided with eight electrical signal receiving ends 61 and one digital signal output end 62. The eight electrical signal receiving ends 61 are respectively connected to the soil humidity sensor 3, six earth pressure cells 4 and the pore water pressure sensor 5 through cables, and the digital signal output end 62 is connected with a cable and led out from the wire passing 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 end 62.

[0072] Specifically, the industrial control board 6 is pasted in the installation groove 131 with sealant.

[0073] It should be noted that after the cable is led out from the wire passing hole 111, the joint needs to be sealed with sealant to prevent water from entering the housing and damaging the industrial control board 6.

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

[0075] The first step is to paste the industrial control board 6 in the installation groove 131 of the installation base plate 13 with sealant and lead out the cable of the digital signal output end 62 from the wire passing hole 111;

[0076] The second step is to fix the soil humidity sensor 3 in the first through hole 121 with sealant, make the probe 31 extend outside the installation side plate 12, then fix the installation side plate 12 on the L-shaped plate with sealant, and finally connect the cable of the soil humidity sensor 3 to the corresponding electrical signal receiving end 61 of the industrial control board 6;

[0077] In the third step, fix the six earth pressure cells 4 in the second through hole 24 with sealant, and make the stress-receiving surface 41 protrude from the seven-sided mask body 2. Then, fix the seven-sided mask body 2 without the equilateral triangle plate 23 on the L-shaped plate and the installation side plate 12 with sealant. Finally, connect the cable of the earth pressure cell 4 to the corresponding electrical signal receiving end 61 of the industrial control board 6;

[0078] In the fourth step, fix the pore water pressure sensor 5 in the third through hole 25 with sealant, and make the water-permeable surface 51 concave into the equilateral triangle plate 23. Then, connect the cable of the pore water pressure sensor 5 to the corresponding electrical signal receiving end 61 of the industrial control board 6. Finally, fix the equilateral triangle plate 23 at the reserved position of the seven-sided mask body 2 with sealant.

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

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

[0081] Eight values can be collected by eight sensors: six normal stresses, one pore water pressure, and one volumetric water content. According to the six normal stresses, the three-dimensional total stress state of a certain point of the soil mass can be calculated. According to the pore water pressure, the degree of saturation of the soil mass can be determined. Then, according to the total stress state combined with the pore water pressure value, the effective stress state under the saturated state can be calculated. According to the total stress state combined with the volumetric water content, the effective stress state under the unsaturated state can be calculated. In this way, the device can be applied to the water level fluctuation scenario where the degree of saturation is in a changing state.

[0082] Embodiment 2

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

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

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

[0086] S2. Input the void ratio e and the hydraulic parameters a d and m of the soil mass at the position to be measured in the monitoring software;

[0087] S3. Place the measuring device described in the embodiment in the air for data collection, and perform feedback adjustment on the sensor according to the collected values to complete the initialization process;

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

[0089] S4. Prepare the model formation and place the measuring device described in Embodiment 1 at the position to be measured in the model formation, making the mounting base plate 13 perpendicular to the direction of gravity, and then conduct data acquisition. The data processor 7 calculates the effective stress state based on the acquired 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 formation soil mass;

[0091] S5. Inject water or drain water from the model formation, synchronously conduct data acquisition, and the data processor 7 calculates the effective stress state based on the acquired values, saves and displays it in real time;

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

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

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

[0095] ;

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

[0097] 2) Conduct saturation judgment according to the pore water pressure value collected by the pore water pressure sensor 5: If , the soil mass is in a saturated state; if , the soil mass is in an unsaturated state;

[0098] 3) Calculate the effective stress state :

[0099] If the soil mass is in a saturated state, calculate according to the following formula:

[0100] ;

[0101] If the soil mass is in an unsaturated state, It is calculated according to the following formula:

[0102] ;

[0103] where, represents the volumetric water content of the soil mass collected by the soil moisture sensor 3.

[0104] More specifically, the calculation formula for the total stress state is derived as follows:

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

[0106] ;

[0107] where, represents the direction cosine. For it is , for it is , for it is Substituting into the above formula, we can get:

[0108] ;

[0109] Therefore, it can be deduced that:

[0110] ;

[0111] That is, the total stress state can be obtained.

[0112] More specifically, the calculation formula for the effective stress state under the unsaturated state is derived as follows:

[0113] First of all, it is known that e, a d , m and θ, and , , , V represents the total volume at a certain point of the soil mass, V V represents the pore volume at this point of the soil mass, V S represents the soil particle volume at this point of the soil mass;

[0114] The expression of the degree of saturation is:

[0115] ;

[0116] The relationship between the degree of saturation and the matrix suction s is:

[0117] ;

[0118] Through the above formula, s can be used to express s, that is:

[0119] ;

[0120] Then:

[0121] ;

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

[0123] The above is only the specific implementation manners of the present invention, enabling those skilled in the art to understand or implement the present invention. Although the foregoing embodiments have been described in detail, those of ordinary skill in the art should understand that: they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements on some or all of the technical features; and these modifications or replacements do not cause the essence of the corresponding technical solutions to 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 (23) 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 (4) 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 hydraulic parameters a of the soil at the intended measurement location into the monitoring software. d and m; 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; 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).

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