Soil pressure gauge

Abstract

The invention discloses a soil pressure gauge. The soil pressure gauge comprises a first body, a strain gauge, a shielding structure, a fiber bragg grating and a second body, wherein the first body and the second body are correspondingly arranged; the first body is provided with an accommodating space which is formed by recessing inwards along the thickness direction of the first body; the shielding structure is arranged between the first body and the second body and is fixedly connected with the first body; the strain gauge is arranged between the first body and the shielding structure and is fixedly connected with the first body; the strain gauge is provided with a strain part; the fiber bragg grating is fixed on the strain gauge; at least one section of the fiber grating is arranged, and at least one section of the fiber grating is arranged corresponding to the strain part. According to the soil pressure meter, the problem of inaccurate precision caused by deformation of the back plate can be avoided, so that the soil pressure can be measured more accurately. The structure is simple, and operation is easy.

Description

Technical Field

[0001] The present invention relates to an earth pressure gauge, in particular to an optical fiber Bragg grating earth pressure gauge. Background Art

[0002] A fiber Bragg grating (FBG) earth pressure gauge is a soil pressure measurement device based on fiber Bragg grating (FBG) technology. It is widely used in civil engineering, underground engineering, building monitoring, and other fields. It is used to monitor the pressure exerted on soil and underground structures in real time, accurately reflecting external pressure changes. It is particularly suitable for complex pressure measurements in underground environments. Its core operating principle is based on the sensing properties of fiber Bragg grating (FBG). FBG is a section of optical fiber whose refractive index within the core varies periodically along the axial direction. When external pressure acts on the earth pressure gauge, it causes a certain deformation. This deformation is transmitted to the internal FBG, causing the period and effective refractive index of the FBG to change, which in turn causes the central wavelength of the reflected light from the FBG to drift. By detecting this wavelength drift, the soil pressure acting on the earth pressure gauge can be accurately measured.

[0003] Earth pressure gauges currently on the market are diaphragm structures, consisting of an upper diaphragm and a back plate. Two support points are welded inside the diaphragm, with a grating fixed between them. When the diaphragm bends inward, the distance between the two support points increases, increasing the tension in the grating and thereby measuring changes in external pressure. However, due to the high force at the interface between the soil and the back plate of the pressure gauge, and the presence of localized stress concentration, the back plate of the pressure gauge experiences uneven load distribution and significant deformation, causing abnormal deformation of the strain gauge within the sensor, resulting in measured values ​​deviating from the true earth pressure value. Summary of the Invention

[0004] In view of this, the present invention aims to provide an earth pressure gauge that can avoid the problem of inaccurate accuracy caused by back plate deformation, thereby more accurately measuring earth pressure. The present invention adopts the following technical solutions to achieve the above-mentioned purpose.

[0005] The present invention provides an earth pressure gauge, comprising a first body, a strain gauge, a shielding structure, a fiber Bragg grating and a second body; wherein, The first body is arranged corresponding to the second body; the first body has an accommodating space formed by being recessed inwardly along the thickness direction of the first body; The shielding structure is provided between the first body and the second body and is fixedly connected to the first body; The strain gauge is provided between the first body and the shielding structure and is fixedly connected to the first body; the strain gauge has a strain portion; The fiber Bragg grating is fixed on the strain gauge; the fiber Bragg grating is provided with at least one section, and at least one section of the fiber Bragg grating is provided corresponding to the strain portion.

[0006] In the present invention, a first body and a second body are disposed in correspondence with each other. The first body has a housing space formed by an inward depression along the thickness direction of the first body. A strain gauge, a shielding structure, and a fiber Bragg grating (FBG) can all be located within the housing space. The strain gauge is located between the first body and the shielding structure, and the fiber Bragg grating (FBG) is fixed to the strain gauge. The fiber Bragg grating is provided in at least one section, and at least one section of the fiber Bragg grating is disposed in correspondence with the strain portion of the strain gauge. Soil pressure from the first body side acts on the first body, causing the first body to deform and transmit the deformation to the strain portion of the strain gauge. When the strain portion deforms, it pulls the fiber Bragg grating, thereby measuring pressure. Simultaneously, when soil compresses the second body, although this causes uneven load distribution and significant deformation in the second body, since the strain gauge does not contact the second body, any abnormal deformation will not be transmitted to the interior of the fiber Bragg grating, resulting in a measurement value closer to the true value.

[0007] According to the soil pressure gauge of the present invention, preferably, the first body includes a first main body portion and a mounting portion; the first main body portion is configured as an internal cantilever structure, and two arc-shaped mounting portions are relatively arranged on the inner wall of the first main body portion, each of the mounting portions is provided with a second through hole, and a first groove and a third through hole are provided on the inner wall area of ​​the first main body portion located between the two mounting portions.

[0008] In the present invention, each mounting portion is provided with a second through-hole, allowing the shielding structure to be connected to the mounting portion via a fastener. A third through-hole is provided on the inner wall region of the first body portion, located between the two mounting portions, allowing the strain gauge to be compressed and secured via a fastener. In certain embodiments, due to the structure of the strain gauge, a first groove is further provided on the inner wall region of the first body portion, located between the two mounting portions, to retain a portion of the strain gauge and thereby better secure the strain gauge.

[0009] In certain embodiments of the present invention, a sealing ring may be provided. A first groove may be provided on the inner side of the lower edge of the first body portion, and the sealing ring may be embedded in the first groove. This can improve the sealing performance of the soil pressure gauge.

[0010] According to the soil pressure gauge of the present invention, preferably, it further includes a pressing structure, which is arranged between the strain gauge and the shielding structure; the pressing structure is configured to press the strain gauge against the inner wall of the first body.

[0011] In the present invention, a pressing mechanism is also provided, which is mainly used to press the strain gauge to prevent deviations in subsequent measurement results due to instability of the strain gauge.

[0012] According to the soil pressure gauge of the present invention, preferably, the strain portion is configured as a polygonal frame structure; the compression structure is provided through the strain portion and fixes the strain gauge on the first body.

[0013] In the present invention, the strain gauge can be configured as a polygonal frame structure, preferably a prismatic frame structure, and even more preferably a hexagonal hollow prism structure. This configuration ensures a linear pressure-deformation response when deformation transitions from vertical to horizontal. This deformation is transmitted to the internal fiber Bragg grating (FBG), causing changes in the FBG's period and effective refractive index, which in turn causes a shift in the central wavelength of the reflected light from the FBG. By detecting this wavelength shift, the soil pressure acting on the soil pressure gauge can be accurately measured, further improving measurement accuracy.

[0014] According to the soil pressure gauge of the present invention, preferably, the strain gauge further includes an extension portion; two extension portions are provided, and the two extension portions are respectively fixed to two ends of the strain portion, and a second groove is provided on the extension portion for fixing the fiber grating.

[0015] In the present invention, the strain gauge may further include a strain gauge body and a protrusion. At least one protrusion is provided, and the protrusion is disposed within the side surface of the strain gauge body. This arrangement allows the protrusion to cooperate with the compression structure, facilitating the tightening of the strain gauge and ensuring the accuracy of the measurement results.

[0016] In the present invention, a second groove is provided on the extension portion, and the second groove is mainly used to accommodate and fix the fiber Bragg grating. At least two fixing parts are provided in the second groove for fixing a section of the fiber Bragg grating. In some embodiments, three fixing parts are provided in the second groove, such as a first fixing part, a second fixing part, and a third fixing part. The first fixing part is provided on one side of the strain portion, and the second fixing part and the third fixing part are provided on the other side of the strain portion. The fiber Bragg grating is provided in two sections, the first section of the fiber Bragg grating is passed through the strain portion body through a through hole, and the two ends of the first section of the fiber Bragg grating are respectively fixed in the first fixing part and the second fixing part, and the second section of the fiber Bragg grating is located in the second groove, and the two ends of the second section of the fiber Bragg grating are respectively fixed in the second fixing part and the third fixing part. In this way, one section of the fiber Bragg grating is used to measure pressure, and the other section of the fiber Bragg grating is used to measure temperature, so that independent signals of pressure and temperature changes can be obtained. The influence caused by temperature is compensated by the reading of the temperature sensor, thereby accurately measuring soil pressure.

[0017] According to the soil pressure gauge of the present invention, preferably, the clamping structure includes a clamping plate, a first baffle and a second baffle; the clamping plate is arranged as a rectangular plate structure; the first baffle is arranged on the clamping plate along the width direction of the clamping plate; the second baffle is arranged on the edge of the clamping plate along the length direction of the clamping plate and is located inside the first baffle.

[0018] In the present invention, the clamping structure primarily adapts to the structure of the strain gauge. In certain embodiments, fifth through-holes are provided at both ends of the clamping plate, corresponding to the third through-hole. A first baffle is positioned between the two fifth through-holes. A second baffle is symmetrically positioned along the length of the clamping plate at its edge and within the first baffle. Thus, the clamping plate is inserted into the strain gauge portion, with the protrusion clamped between the two first baffles and the two second baffles. A fixing member passes through the fifth and third through-holes in sequence, pressing one end of the strain gauge portion against the first groove, while simultaneously connecting the clamping structure to the first main body. This structure can better compress the strain gauge, preventing deviations in subsequent measurement results due to an unstable strain gauge.

[0019] According to the soil pressure gauge of the present invention, preferably, the shielding structure includes a first shielding portion and a second shielding portion; the first shielding portion is arranged on the second shielding portion, and the length of the first shielding portion is less than the length of the second shielding portion; a second slot is provided on the first shielding portion, a pin hole is provided on the second shielding portion at a position corresponding to the second slot, a sixth through hole corresponding to the second through hole on the mounting portion is provided near both ends along the width direction of the second shielding portion, and a seventh through hole is provided on the side surface along the length direction of the second shielding portion. Such a structure can better isolate the strain gauge from the second body to prevent inaccurate measurement structure caused by abnormal deformation.

[0020] According to the earth pressure gauge of the present invention, the second body is preferably configured as a circular plate-shaped structure that is detachably connected to the first body. This structure of the second body can withstand and reduce the pressure of the soil on its side to a certain extent, thereby further reducing the impact of abnormal deformation on the measurement results.

[0021] In some embodiments, a plurality of first through holes may be provided on the lower edge of the first body portion, and a plurality of ninth through holes corresponding to the first through holes may be provided along the circumference of the second body portion. The first body and the second body are connected by a plurality of fixing members.

[0022] In other embodiments, a ring groove matching the fourth groove of the first body may be provided around the second body, and the sealing ring may be provided in the ring groove of the second body and embedded into the first body through the elastic force and friction force of the sealing ring.

[0023] According to the earth pressure gauge of the present invention, preferably, a third slot is further provided on the second body for accommodating the shielding structure.

[0024] According to the soil pressure gauge of the present invention, preferably, it further comprises a connecting head; the connecting head is connected to the side surface of the first body portion.

[0025] In the present invention, a plurality of connectors can be provided for locking and fixing the cables. In some embodiments, the connector can be provided as a cable connector.

[0026] Compared with the prior art, the soil pressure gauge of the present invention has the following beneficial effects: (1) It can better improve the influence of back plate deformation on accuracy and improve the accuracy of soil pressure measurement. (2) The special strain gauge structure can improve the nonlinearity of force transmission, so that the measurement results are highly accurate within different pressure ranges.

[0027] (3) By setting up multiple fiber Bragg gratings, independent signals of pressure and temperature changes can be obtained, which can compensate for the effects caused by temperature and thus accurately measure soil pressure.

[0028] (4) Fiber Bragg gratings are not easy to break, which improves their durability. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 Exploded view of the earth pressure gauge of the present invention.

[0030] Figure 2 This is a structural diagram of the first body of this embodiment 1.

[0031] Figure 3 Schematic diagram of the structure of the strain gauge and fiber Bragg grating of the present invention.

[0032] Figure 4 It is a structural schematic diagram of the compression structure of the present invention.

[0033] Figure 5 It is a structural schematic diagram of the shielding structure of the present invention.

[0034] Figure 6 This is a schematic diagram of the second main body structure of Example 1.

[0035] Figure 7 This is a schematic diagram of the second main body structure of Example 2.

[0036] Figure 8 This is a connection diagram of the first body and the second body of Example 2.

[0037] The following are the descriptions of the reference numerals: 1-first body, 11-first body portion, 111-first through hole, 112-first slot, 113-third through hole, 114-first groove, 12-mounting portion, 121-second through hole; 2 - strain gauge, 21 - strain portion, 211 - strain portion body, 2111 - eighth through hole, 212 - protruding portion, 213 - transition portion, 22 - extending portion, 221 - second groove, 2211 - first fixing portion, 2212 - second fixing portion, 2213 - third fixing portion; 3-pressing structure, 31-pressing plate, 311-fifth through hole, 32-first baffle, 33-second baffle; 4-shielding structure, 41-first shielding portion, 411-first slot, 42-second shielding portion, 421-pin hole, 422-sixth through hole, 423-seventh through hole; 5-Fiber Bragg grating; 6-second body, 61-ninth through hole, 62-third groove, 63-circular groove; 71-first fixing member, 72-second fixing member, 73-third fixing member, 74-fourth fixing member; 8-Connector. DETAILED DESCRIPTION

[0038] The present invention will be further described below with reference to specific embodiments, but the protection scope of the present invention is not limited thereto.

[0039] Example 1 Figure 1 Exploded view of the earth pressure gauge of the present invention. Figure 2 Schematic diagram of the structure of the first body of this embodiment. Figure 3 Schematic diagram of the structure of the strain gauge and fiber Bragg grating of the present invention. Figure 4 It is a structural schematic diagram of the compression structure of the present invention. Figure 5 It is a structural schematic diagram of the shielding structure of the present invention. Figure 6 Schematic diagram of the second main body structure of this embodiment.

[0040] like Figure 1 and Figure 3As shown, the soil pressure gauge includes a first body 1, a strain gauge 2, a clamping structure 3, a shielding structure 4, a fiber grating 5, a second body 6, a fixing part and a connector 8. The first body 1 is arranged corresponding to the second body 6, and the first body 1 is located above the second body 6, and the two are detachably connected; the first body 1 has a accommodating space formed by an inward depression along the thickness direction of the first body 1; the shielding structure 4 is arranged between the first body 1 and the second body 6 and is fixed to the first body 1; the strain gauge 2 is arranged between the first body 1 and the shielding structure 4 and is fixed to the first body 1 through the clamping structure 3; the fiber grating 5 is fixed on the strain gauge 2. The soil pressure gauge formed in this way can better improve the influence of the deformation of the second body on the accuracy and improve the accuracy of measuring soil pressure. Specifically, like Figure 2 As shown, the first body 1 includes a first body portion 11, a mounting portion 12, and a sealing ring (not shown). The first body portion 11 is generally configured as an internal cantilever structure, with two arc-shaped mounting portions 12 disposed opposite each other on the inner wall of the first body portion 11. A plurality of first through-holes 111 are disposed on the lower edge of the first body portion 11, and each mounting portion 12 is provided with a second through-hole 121. A first groove 112 and a third through-hole 113 are disposed on the inner wall region of the first body portion 11 located between the two mounting portions 12. A first groove 114 is disposed on the inner side of the lower edge of the first body portion 11, and the sealing ring is embedded in the first groove 114. A fourth through-hole (not shown) is disposed on the side of the first body portion 11. Since the above through-holes and grooves need to cooperate with the corresponding subsequent structures, they will be described in detail in the following sections for easier understanding.

[0041] like Figure 3As shown, the strain gauge 2 includes a strain portion 21 and an extension portion 22. The strain portion 21 is configured as a prismatic frame structure, comprising a strain portion body 211, a protrusion 212, and a transition portion 213. The strain portion body 211 is generally in the shape of a hollow hexagonal prism. Two protrusions 212 are provided, one on each of two parallel side surfaces of the strain portion body 211 that form an obtuse angle with adjacent side surfaces. Each protrusion 212 is connected to two adjacent side surfaces via a transition portion 213. One end of the strain portion 21 with the protrusion 212 is positioned corresponding to the first groove 112 of the first main body 11. Two extensions 22 are provided, each of which is a rectangular plate-shaped structure. They are horizontally fixed to the strain portion body 211 at either end, away from the protruding portion 212. Through-holes are defined at the connection points. Each extension 22 is provided with a second groove 221, within which are located a first fixing portion 2211, a second fixing portion 2212, and a third fixing portion 2213. The first fixing portion 2211 is located on one side of the strain portion 21, while the second and third fixing portions 2212 and 2213 are located on the other side. In this embodiment, the fiber Bragg grating 5 is provided in two sections. The first section of the fiber Bragg grating 5 is inserted through the through-holes within the strain portion body 211, with its ends fixed to the first fixing portion 2211 and the second fixing portion 2212, respectively. The second section of the fiber Bragg grating 5 is located within the second groove 221, with its ends fixed to the second fixing portion 2212 and the third fixing portion 2213, respectively. The first section of the fiber Bragg grating 5 is used to measure pressure, and the second section of the fiber Bragg grating 5 is used to measure temperature. This allows independent signals of pressure and temperature changes to be obtained. The influence of temperature is compensated by the reading of the temperature sensor, resulting in a more accurate measurement of soil pressure.

[0042] like Figure 4 As shown, the clamping structure 3 is configured as a plate-like structure, which includes a clamping plate 31, a first baffle 32, and a second baffle 33. Fifth through holes 311 are provided at both ends of the clamping plate 31, and the fifth through holes 311 are provided corresponding to the third through holes 113. The first baffle 32 is symmetrically arranged on the clamping plate 31 along the width direction of the clamping plate 31 and is located between the two fifth through holes 311. The second baffle 33 is symmetrically arranged at the edge of the clamping plate 31 along the length direction of the clamping plate 31 and is located inside the first baffle 32. That is, the clamping plate 31 is inserted into the strain part body 211, and the protrusion 212 is clamped between the two first baffles 31 and the two second baffles 33. The first fixing member 71 passes through the fifth through hole 311 and the third through hole 113 in sequence, and presses one end of the strain part 21 with the protrusion 212 into the first groove 112, while connecting the clamping structure 3 to the first body part 11.

[0043] like Figure 5As shown, the shielding structure 4 includes a first shielding portion 41 and a second shielding portion 42, both of which are configured as rectangular plate structures. The first shielding portion 41 is disposed on the second shielding portion 42, and the length of the first shielding portion 41 is shorter than that of the second shielding portion 42. A second slot 411 is provided on the first shielding portion 41, and a pin hole 421 is provided on the second shielding portion 42 at a position corresponding to the second slot 411. Sixth through holes 422 are provided near both ends along the width direction of the second shielding portion 42, and a seventh through hole 423 is provided on the side surface of the second shielding portion 42 along the length direction. Among them, the second groove body 31 is used to accommodate the other end of the strain part 21 with the protrusion 212, and an eighth through hole 2111 is opened on the end surface; the push pin is inserted into the pin hole 421 and the eighth through hole 2111, and at the same time the second fixing member 72 passes through the seventh through hole 423 and presses the push pin tightly, thereby fixing the strain part 21; the sixth through hole 422 and the second through hole 121 on the mounting part 12 are arranged correspondingly, and the third fixing member 73 passes through the sixth through hole 422 and the second through hole 121 in sequence to install the shielding structure 3 on the mounting part 12 of the first body 1.

[0044] like Figure 6 As shown, the second body 6 is configured as a circular plate-like structure. A plurality of ninth through holes 61 corresponding to the first through holes 111 are circumferentially provided along the upper edge of the second body 6. The fourth fixing member 74 sequentially passes through the first through holes 111 and the ninth through holes 61 to connect the first body 1 and the second body 6. A third slot 62 is also provided on the second body 6 for accommodating the shielding structure 4.

[0045] The connector 8 is provided with a threaded structure, which cooperates with the fourth through hole on the side of the first body portion 11, thereby connecting the connector to the first body portion 11. In this embodiment, the connector 8 can be configured as a cable connector.

[0046] The working process of the earth pressure gauge of this embodiment is described in detail below: The strain gauge 2 is mounted between the first body 1 and the shielding structure 4. The second body 2 reduces soil pressure on its side. Soil pressure on the first body 1 acts on the first body 1, causing it to deform and transmit this deformation to the strain gauge 2. The strain gauge 21 is then deformed, shifting the deformation from vertical to horizontal. This increases the distance between the first fixing portion 2211 and the second fixing portion 2212, pulling on the fiber Bragg grating 5, causing changes in its period and effective refractive index. This, in turn, shifts the central wavelength of the light reflected by the fiber Bragg grating 5. By detecting this wavelength shift, the soil pressure acting on the soil pressure gauge can be accurately measured. Furthermore, due to the unique structural design of the strain gauge 2, the pressure-deformation response is linear, resulting in highly accurate measurement results across a wide range of pressures.

[0047] Fiber Bragg Grating 5 uses two FBG sensors: one for measuring pressure and the other for measuring temperature. By installing the FBG sensors at different locations, independent signals for pressure and temperature changes can be obtained. Temperature effects are compensated for by the temperature sensor readings, resulting in more accurate soil pressure measurements.

[0048] Example 2 Figure 7 Schematic diagram of the structure of the second body of this embodiment. Figure 8 This is a connection diagram of the first body and the second body of this embodiment.

[0049] like Figure 7 and 8 As shown, this embodiment is the same as in Example 1, except that the first through hole 111 is not provided on the first body 1, and a ring groove 63 is provided around the second body 6 to match the fourth groove, and the sealing ring is disposed in the ring groove 63 of the second body 6. In this embodiment, the second body 6 is embedded in the first body 1 by the elastic force and friction of the sealing ring, which can further improve the measurement accuracy.

[0050] The present invention is not limited to the above-mentioned embodiments. Any modification, improvement, or substitution that can be conceived by those skilled in the art without departing from the essential content of the present invention shall fall within the scope of the present invention.

Claims

1. An earth pressure gauge, characterized in that: It comprises a first body (1), a strain gauge (2), a shielding structure (4), a fiber grating (5) and a second body (6); wherein, The first body (1) and the second body (6) are arranged correspondingly; the first body (1) has an accommodation space formed by being recessed inwardly along the thickness direction of the first body (1); The shielding structure (4) is provided between the first body (1) and the second body (6) and is fixedly connected to the first body (1); The strain gauge (2) is provided between the first body (1) and the shielding structure (4) and is fixedly connected to the first body (1); the strain gauge (2) has a strain portion (21); The optical fiber Bragg grating (5) is fixed on the strain gauge (2); the optical fiber Bragg grating (5) is provided with at least one section, and at least one section of the optical fiber Bragg grating (5) is provided corresponding to the strain portion (21).

2. The earth pressure gauge according to claim 1, characterized in that: The first body (1) comprises a first body portion (11) and a mounting portion (12); the first body portion (11) is configured as an inner cantilever structure, two arc-shaped mounting portions (12) are arranged opposite to each other on the inner wall of the first body portion (11), each mounting portion (12) is provided with a second through hole (121), and a first groove (112) and a third through hole (113) are provided on the inner wall area of ​​the first body portion (11) located between the two mounting portions (12).

3. The earth pressure gauge according to claim 1, characterized in that: It also includes a pressing structure (3), which is arranged between the strain gauge (2) and the shielding structure (4); the pressing structure (3) is configured to press the strain gauge (2) onto the inner wall of the first body (1).

4. The earth pressure gauge according to claim 3, characterized in that The strain portion (21) is configured as a polygonal frame structure; the pressing structure (3) is passed through the strain portion (21) and fixes the strain gauge (2) on the first body (1).

5. The earth pressure gauge according to claim 4, characterized in that: The strain gauge (2) further comprises an extension portion (22); two extension portions (22) are provided, and the two extension portions are respectively fixed to two ends of the strain portion (21); a second groove (221) is provided on the extension portion (22) for fixing the optical fiber Bragg grating (5).

6. The earth pressure gauge according to claim 3, characterized in that: The clamping structure (3) comprises a clamping plate (31), a first baffle (32) and a second baffle (33); the clamping plate (31) is configured as a rectangular plate-shaped structure; the first baffle (32) is disposed on the clamping plate (31) along the width direction of the clamping plate (31); and the second baffle (33) is disposed at the edge of the clamping plate (31) along the length direction of the clamping plate (31) and is located within the first baffle (32).

7. The earth pressure gauge according to claim 2, characterized in that: The shielding structure (4) comprises a first shielding portion (41) and a second shielding portion (42); the first shielding portion (41) is arranged on the second shielding portion (42), and the length of the first shielding portion (41) is less than the length of the second shielding portion (42); a second slot body (31) is arranged on the first shielding portion (41), and the second slot body (31) is arranged corresponding to the first slot body (112); a pin hole (421) is provided on the second shielding portion (42) at a position corresponding to the second slot body (31), a sixth through hole (422) corresponding to the second through hole (121) on the mounting portion (12) is provided near both ends along the width direction of the second shielding portion (42), and a seventh through hole (423) is provided on the side surface along the length direction of the second shielding portion (42).

8. The earth pressure gauge according to claim 2, characterized in that: The second body (6) is configured as a circular plate-shaped structure, which is detachably connected to the first body (1).

9. The earth pressure gauge according to claim 8, characterized in that A third slot (62) is also provided on the second body (6) for accommodating the shielding structure (4).

10. The earth pressure gauge according to claim 2, characterized in that: It also includes a connecting head (8); the connecting head (8) is connected to the side surface of the first main body portion (11).

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