CN213985493U

CN213985493U - Three-dimensional soil pressure measuring device for model test

Info

Publication number: CN213985493U
Application number: CN202022939920.3U
Authority: CN
Inventors: 章慧健; 曹攀; 张帅; 赵磊; 董石林
Original assignee: Southwest Jiaotong University
Current assignee: Southwest Jiaotong University
Priority date: 2020-12-10
Filing date: 2020-12-10
Publication date: 2021-08-17
Anticipated expiration: 2030-12-10

Abstract

The utility model provides a three-dimensional soil pressure measurement device for model test relates to tunnel engineering research technical field, and it includes the base, and the outer wall parcel of base has the isolation layer, is provided with a minute pressure measurement mechanism on the three mutually perpendicular's of base face respectively. Every divides pressure measurement mechanism to include from the sunken measurement chamber in inboard in the base surface, measures fixedly connected with sac in the chamber, on the free end of sac all was fixed in the loading board, the loading board with measure the lateral wall sealing sliding connection in chamber, keep away from on the measurement chamber of sac one side at the loading board and be provided with spacing fender platform, be connected with the liquid column pipe and the blast pipe rather than inside intercommunication on the sac, liquid column pipe and blast pipe seal wear out the base back and extend along vertical top. The problem of only can measure vertical force and easily receive the transverse force interference among the current model test soil pressure measurement technique is solved.

Description

Three-dimensional soil pressure measuring device for model test

Technical Field

The utility model relates to a tunnel engineering research technical field especially relates to a three-dimensional soil pressure measurement device for model test.

Background

The internal soil pressure of structures such as slopes, foundation pits, roadbeds, dams, tunnels and the like is always one of the most important measurement items in the construction process. The common earth pressure measuring elements in the prior art mainly have structural forms of a vibrating wire type, a differential resistance type, a resistance strain type and the like, and the accuracy of an earth pressure actual measurement result is comprehensively controlled by an element measuring principle, construction interference, environmental factors and the like. Taking a vibrating wire type soil pressure cell as an example, the basic measuring element of the vibrating wire type soil pressure cell consists of an elastic membrane, a steel wire and a coil, if a measured medium is very loose, such as loose sand, soft soil and the like, the soil pressure measured value is basically close to an actual value, but along with the increase of the rigidity of the measured medium, the accuracy and the reliability of a result obtained by adopting a parameter obtained by calibrating the hydraulic pressure or the air pressure to calculate the soil pressure actual measurement data are sharply reduced.

The measurement of soil pressure requires that the soil pressure measuring element is buried in the soil, and the soil surrounds the soil pressure measuring element. Although the existing soil pressure cell basically meets the precision required by construction, the precision required by scientific research is far from being met, and the main reason for low precision is that a lot of uneven forces are generated on the stressed surface of the soil pressure cell in a direction perpendicular to the stressed surface and lateral forces on the side, and the forces can greatly influence the measured data of the soil pressure cell, so that the error of the measured data is large, and particularly the influence of the lateral forces is caused. The soil pressure cells in the prior art can only carry out one-dimensional pressure measurement in a single direction, and can not measure non-vertical forces at other measured positions such as lateral force, so that if soil pressure in other directions is measured, other soil pressure measurement cells can only be buried in a nearby area and towards different directions for measurement, and the measured pressure can cause errors due to the influence of factors such as soil, a buried construction method and the like because the soil pressure cells are not in the same position, and the requirement of experimental research can not be met.

SUMMERY OF THE UTILITY MODEL

To the above-mentioned problem among the prior art, the utility model provides a three-dimensional soil pressure measurement device for model test has solved and has only can measure the problem of getting vertical force and easily receiving the transverse force interference among the current model test soil pressure measurement technique.

In order to achieve the purpose of the invention, the technical scheme adopted by the utility model is as follows:

the utility model provides a three-dimensional soil pressure measurement device for model test, it includes the base, and the outer wall parcel of base has the isolation layer, is provided with a minute pressure measurement mechanism on the three mutually perpendicular's of base respectively. Every divides pressure measurement mechanism to include from the sunken measurement chamber in inboard in the base surface, measures fixedly connected with sac in the chamber, on the free end of sac all was fixed in the loading board, the loading board with measure the lateral wall sealing sliding connection in chamber, keep away from on the measurement chamber of sac one side at the loading board and be provided with spacing fender platform, be connected with the liquid column pipe and the blast pipe rather than inside intercommunication on the sac, liquid column pipe and blast pipe seal wear out the base back and extend along vertical top.

The utility model has the advantages that: the isolating layer is directly wrapped outside the base, so that the processing technology is simplified, and the processing quality is easy to ensure; the acting force of the soil pressure on the base can be isolated through the isolation layer, the base is prevented from conducting the side pressure to the partial pressure measuring mechanism, the measuring precision of the partial pressure measuring mechanism is prevented from being influenced, and the accuracy of measuring the acting force perpendicular to the bearing plate of each partial pressure measuring mechanism is improved. The three partial pressure measuring mechanisms respectively measure acting forces in three mutually perpendicular directions, so that three-dimensional acting force measurement is realized at the same place, and the influence of external factors such as soil and difference of embedding modes on a force measurement result is reduced.

In the scheme, the bearing plate is pushed to extrude the liquid bag by acting the soil pressure on the bearing plate, so that the liquid in the liquid bag rises along the liquid column pipe, and the soil pressure can be calculated by recording the height of the liquid level in the liquid column pipe, so that the whole soil pressure measuring device has a simpler structure, does not have an electrical element, does not need to run a wire in a soil body, and is more convenient to maintain; the method has higher measurement precision, is more suitable for small-range measurement in a laboratory, and is simple to operate.

Drawings

Fig. 1 is a perspective view of a three-dimensional soil pressure measuring device used for a model test.

Fig. 2 is a sectional view of a three-dimensional soil pressure measuring device used for a model test.

Fig. 3 is an enlarged view of a portion a in fig. 2.

Fig. 4 is a perspective view of the flat exhaust pipe in fig. 2.

Wherein, 1, a base; 2. an isolation layer; 21. a rigid housing; 22. a buffer layer; 3. a measurement cavity; 4. a liquid sac; 5. a carrier plate; 51. enclosing plates; 6. a liquid column tube; 7. a flexible seal; 71. a flexible waterproof cloth; 72. an annular sleeve; 8. a limiting stop table; 9. an exhaust pipe; 91. an exhaust flat pipe; 92. an exhaust hole; 93. a flexible hose.

Detailed Description

The following description of the embodiments of the present invention is provided to facilitate the understanding of the present invention by those skilled in the art, but it should be understood that the present invention is not limited to the scope of the embodiments, and various changes will be apparent to those skilled in the art as long as they are within the spirit and scope of the present invention as defined and defined by the appended claims, and all inventions contemplated by the present invention are protected.

As shown in fig. 1 to 3, the three-dimensional soil pressure measuring device for model test comprises a base 1, wherein an isolation layer 2 is wrapped on the outer wall of the base 1, and three mutually perpendicular surfaces of the base 1 are respectively provided with a partial pressure measuring mechanism.

Every divides pressure measurement mechanism to include from the sunken measurement chamber 3 in the inboard in 1 surface of base, fixedly connected with sac 4 in the measurement chamber 3, on loading board 5 was all fixed in to the free end of sac 4, loading board 5 and the sealed sliding connection of lateral wall of measuring chamber 3, be provided with spacing fender platform 8 on the measurement chamber 3 of loading board 5 keeping away from sac 4 one side, be connected with on the sac 4 rather than the liquid column pipe 6 and the blast pipe 9 of inside intercommunication, liquid column pipe 6 and blast pipe 9 are sealed to be worn out and are extended along vertical top behind the base 1.

Preferably, the base 1 is a regular hexagonal structure, each surface is a plane, and adjacent surfaces are perpendicular to each other, so that the verticality of the base 1 can be ensured more easily when the base is buried in a soil body, and the accuracy of component force measured by the three component pressure measuring mechanisms can be improved. The base 1 is a solid structure to increase the stability of the base 1. The isolation layer 2 includes a rigid housing 21 and a buffer layer 22 filled between the rigid housing 21 and the outer wall of the base 1. The rigid shell 21 may be a carbon steel plate wrapped outside the base 1 and welded to the base 1, and the buffer layer 22 may be a medium having a buffer function, such as buffer cotton or foam balls, filled between the rigid shell 21 and the base 1. The rigid shell 21 can reduce the compression of the lateral static pressure, and the buffer ball can buffer the pressure transmitted by the rigid shell.

The liquid bag 4 is a sealed pressure container for containing liquid such as water. The liquid bag 4 is oval sphere, and the bottom of liquid bag 4 is fixed in the bottom plate of measuring chamber 3 through modes such as viscose on, and the side wall of liquid bag 4 is fixed in on the lateral wall of measuring chamber 3, and the top of liquid bag 4 is fixed in on the bottom surface of loading board 5. The top end of the oval spherical liquid bag 4 is an upward convex cambered surface, and the upward convex cambered surface is contacted with the bearing plate 5, so that the bearing plate 5 can quickly cause the change of liquid in the liquid bag 4 after being subjected to soil pressure, and the sensitivity of pressure measurement is improved. Simultaneously, only the top end of the liquid bag 4 is used as a free end, and the bottom end and the side surrounding edge are fixed with the measuring cavity 3, so that the liquid bag 4 can not move relative to the measuring cavity 3 and can only be squeezed by the bearing plate 5 to discharge the liquid contained in the liquid bag from the liquid column tube 6.

For top sac 4 in the orientation shown in fig. 1, fluid column tube 6 is sealed into sac 4 from the side margins of sac 4. Liquid column pipe 6 passes base 1 and is fixed with base 1, and the side surrounding edge of liquid bag 4 bonds as an organic whole with measuring chamber 3, and liquid column pipe 6 lets in liquid bag 4 from this department in, with the help of base 1 fixed to liquid column pipe 6, can avoid at the junction of liquid column pipe 6 and liquid bag 4 because the liquid bag 4's that the fluid cross-section sudden change leads to removal or drift, can improve the stability that liquid bag 4 fixed in measuring chamber 3, and then improve the accurate nature of power measurement. The exhaust pipe 9 is arranged at the upper part of the liquid column pipe 6, the flat exhaust pipe 91 is fixed at the inner side of the top part of the liquid bag 4, the flat exhaust pipe 91 is a hard pipe with smooth appearance and is arranged in parallel with the bearing plate 5, so that the bearing plate 5 can act on the flat exhaust pipe 91 in the process of moving downwards,

one end of the flat exhaust pipe 91 is closed, the other end is open, and the open end penetrates through the liquid bag 4 in a sealing manner and then is connected with the exhaust pipe 9 fixed on the base 1 through the flexible hose 93. The exhaust pipe 9 needs to be located outside the moving range of the carrying plate 5, and the surplus length of the flexible hose 93 needs to be insufficient to prevent the carrying plate 5 from moving. As shown in fig. 4, at least one vent hole 92 is formed in the middle of the bottom plate of the flat vent pipe 91, and gas in the liquid bag 4 can be exhausted through the vent hole 92 in the process of filling liquid into the liquid bag 4 through the liquid column pipe 6.

For the liquid bag 4 on the left and front side of the orientation shown in fig. 1, the liquid column tube 6 is sealingly passed into the lower part of the liquid bag 4 from the side peripheral edge of the liquid bag 4, the air vent tube 9 is sealingly passed into the upper part of the liquid bag 4 from the side peripheral edge of the liquid bag 4, and when liquid is filled into the liquid bag 4 through the liquid column tube 6, air in the liquid bag 4 is exhausted from the air vent tube 9.

Bearing plate 5 and measurement chamber 3 clearance fit, there is the clearance between the outer wall of the inner wall of measurement chamber 3 and bearing plate 5 promptly to guarantee that bearing plate 5 can smoothly slide along the axial of measuring chamber 3. A shroud 51 extending away from the end of the reservoir 4 is integrally formed along the edge of the carrier plate 5, the shroud 51 being connected to the base 1 outside the measurement cavity 3 by a flexible seal 7. The arrangement of the coaming 51 can prolong the matching length of the bearing plate 5 and the measuring cavity 3 in the axial direction, so that the bearing plate is not easy to incline when being subjected to soil pressure, and the matching coaxiality of the bearing plate and the measuring cavity is improved. Meanwhile, the surrounding plate 51 is arranged at one end far away from the liquid bag 4, so that the surrounding plate 51 can be prevented from puncturing the liquid bag 4 in the moving process of the bearing plate 5; in addition, the gap between the inner wall of the measuring cavity 3 and the outer wall of the bearing plate 5, which is filled with soil, can be reduced, and the risk of blockage is reduced.

The flexible sealing element 7 comprises a flexible waterproof cloth 71 and annular sleeves 72 fixed at two ends of the flexible waterproof cloth 71, and the annular sleeves 72 at two ends are fixedly sleeved on the coaming 51 and the base 1 outside the measuring cavity 3 respectively. The flexible sealing element 7 can prevent soil from entering a gap between the inner wall of the measuring cavity 3 and the outer wall of the bearing plate 5 to cause the bearing plate 5 to be incapable of moving, and the reliability of the native pressure measuring device is improved.

The annular sleeve 72 is provided with an annular groove with an opening at the bottom surface and a rectangular cross section, so that the annular sleeve 72 can be straddled on the annular boss on the top surface of the coaming 51 or the base 1 and is bonded, and the bonding surface has three surfaces, so that the fixation is firmer. The length of the flexible tarp 71 is not less than the sliding range of the bearing plate 5, so that the bearing plate 5 cannot be pulled by the flexible tarp 71 in the whole up-and-down sliding process.

The liquid column pipes 6 in the three partial pressure measuring mechanisms penetrate out of the top surface of the base 1 and extend vertically upwards. Three liquid column pipe 6 all is located the top surface of base 1, when burying native pressure measurement device underground, and it is more convenient to protect liquid column pipe 6, also can effectively reduce the probability of damaging liquid column pipe 6 when backfilling the soil body.

The liquid column tube 6 is a transparent tube and is provided with liquid level scale marks on the tube wall outside the base 1. The transparent tube is convenient for observing the change of the liquid level height, in order to improve the identification degree, the color can be added into the liquid, and the liquid level scale mark is convenient for rapidly reading the liquid level height.

The use method of the three-dimensional soil pressure measuring device for the model test comprises the following steps:

s1, burying the three-way soil pressure measuring device in a soil body to be measured in pressure, enabling the inclination of the three-way soil pressure measuring device to be less than or equal to 0.5%, and tamping backfill soil to enable the upper part of the liquid column pipe 6 to be exposed out of the soil body;

s2, the liquid injection mechanism with flow record is used for connecting the liquid column tube 6 to inject liquid into the corresponding liquid bag 4, the liquid injection is stopped until the liquid injection cannot be continued, namely the bearing plate 5 moves up to the position of the limit stop table 8 when the liquid injection cannot be performed, the limit stop table 8 is an annular convex strip fixed on the inner wall of the measurement cavity 3 and used for stopping the bearing plate 5 from moving up to realize the limit function, at the moment, the liquid bag 4 is also the critical position for filling, and after the liquid filling, the liquid column tube 6 and the exhaust pipe 9 are ensured to have liquid. Recording the liquid level height in the liquid column pipe 6 as the initial liquid level height;

and S3, observing and recording the liquid level height change in the liquid column pipe 6 in real time.

Claims

1. The three-dimensional soil pressure measuring device for the model test is characterized by comprising a base (1), wherein an isolation layer (2) wraps the outer wall of the base (1), and three mutually vertical surfaces of the base (1) are respectively provided with a partial pressure measuring mechanism;

every divide pressure measurement mechanism to include from base (1) surface is to inboard sunken measurement chamber (3), fixedly connected with sac (4) in measurement chamber (3), the free end of sac (4) all is fixed in on loading board (5), loading board (5) with measure the sealed sliding connection of lateral wall in chamber (3) loading board (5) are kept away from sac (4) one side be provided with spacing fender platform (8) on measuring chamber (3), be connected with liquid column pipe (6) and blast pipe (9) rather than inside intercommunication on sac (4), blast pipe (9) with liquid column pipe (6) are sealed wear out extend along vertical top behind base (1).

2. The tri-directional soil pressure measuring apparatus for model test as claimed in claim 1, wherein the insulation layer (2) comprises a rigid outer shell (21) and a buffer layer (22) filled between the rigid outer shell (21) and the outer wall of the base (1).

3. The three-dimensional soil pressure measuring device for the model test according to claim 1, wherein the liquid bag (4) is in an oval sphere shape, the bottom end of the liquid bag (4) is fixed on the bottom plate of the measuring cavity (3), the side edges of the liquid bag (4) are fixed on the side walls of the measuring cavity (3), the top end of the liquid bag (4) is fixed on the bottom surface of the bearing plate (5), and the liquid column tube (6) is hermetically communicated into the liquid bag (4) from the side edges of the liquid bag (4).

4. The three-dimensional soil pressure measuring device for model test as claimed in claim 1, wherein said carrier plate (5) is clearance fitted with said measuring cavity (3), a shroud (51) extending away from said sac (4) is integrally formed along the edge of said carrier plate (5), and said shroud (51) is connected with said base (1) outside said measuring cavity (3) by a flexible seal (7).

5. The three-way soil pressure measuring device for model test according to claim 4, wherein the flexible sealing member (7) comprises a flexible tarp (71) and annular sleeves (72) fixed at both ends of the flexible tarp (71), the annular sleeves (72) at both ends are fixedly sleeved on the coaming (51) and the base (1) outside the measuring cavity (3), respectively, and the length of the flexible tarp (71) is not less than the sliding range of the bearing plate (5).

6. The tri-dimensional soil pressure measuring device for model test as claimed in claim 1, wherein the liquid column pipes (6) of the three partial pressure measuring mechanisms all penetrate out from the top surface of the base (1) and vertically extend upward.

7. The tri-directional soil pressure measuring device for model test according to claim 1 or 6, wherein the liquid column tube (6) is a transparent tube and liquid level scale lines are arranged on the tube wall outside the base (1).