Spherical soil stress testing device

Abstract

The utility model relates to the technical field of soil stress testing, in particular to a spherical soil stress testing device which comprises an elastic spherical shell, a cavity is formed in the elastic spherical shell, a Y-shaped air tap is arranged on the elastic spherical shell, the cavity is connected with an inflation pipeline through the Y-shaped air tap, six first pressure sensors are arranged in the cavity, and a second pressure sensor is arranged in the cavity. The first pressure sensors are distributed along the circumference of the center of the elastic spherical shell in an array mode, every two adjacent first pressure sensors are perpendicular to each other, the first pressure sensors are connected through a six-way support, and the center of the six-way support coincides with the center of the elastic spherical shell. According to the utility model, by arranging the six first pressure sensors which are distributed along the circumference of the sphere center of the elastic spherical shell in an array manner, the three-dimensional stress in the soil body where the elastic spherical shell is located can be tested at the same time; and the interior of the elastic spherical shell is inflated and pressurized to be equivalent to soil stress states under different working conditions, and detection is more comprehensive.

Description

Technical Field

[0001] The utility model relates to the technical field of soil stress testing, in particular to a spherical soil stress testing device. Background Art

[0002] With the development of information technology and civil engineering, economic benefits and safety issues are becoming more and more important. The accuracy of soil stress measurement is directly related to engineering benefits, engineering safety and potential hidden dangers. In soil stress measurement tests, since soil is a porous, multi-phase, heterogeneous medium, its mechanical properties are significantly affected by factors such as stress magnitude, stress direction, stress path, and stress history. Usually, in engineering practice, the stress of a point in the soil is expressed as a vector. However, in scientific experiments and engineering practice, it is necessary to measure the three-dimensional stress state. In three-dimensional space, a vector contains six degrees of freedom, so six independent variables are required to characterize the stress state of a point. According to elastic-plastic mechanics, it can be simplified to three stress components, three magnitude quantities, and three direction quantities of the principal stress coordinate system. Therefore, only by accurately obtaining the stress magnitude and direction of a point in the soil at the same time can the stress state of the soil be expressed, and then the safety and stability evaluation and construction maintenance analysis of geotechnical engineering can be carried out scientifically.

[0003] At present, in the engineering field, the three-dimensional stress state of soil is often obtained by orthogonalizing multiple unidirectional soil pressure test boxes. This method ignores the direction of each stress, ignores the shear stress of the stress unit body, and cannot fully reflect the changes in the stress state in the soil, resulting in inconsistency between the measured stress state and the actual stress state of the project.

[0004] In order to solve the above-mentioned engineering problems, the utility model provides a spherical soil stress testing device which can simultaneously test the three-dimensional stress inside the soil. Utility Model Content

[0005] The utility model aims to provide a spherical soil stress testing device, which can simultaneously test the three-dimensional stress inside the soil body and is simple and practical.

[0006] The utility model provides a spherical soil stress testing device, comprising an elastic spherical shell, wherein a cavity is arranged inside the elastic spherical shell, a Y-shaped air nozzle is arranged on the elastic spherical shell, the cavity is connected to an air charging pipe via the Y-shaped air nozzle, six first pressure sensors are arranged in the cavity, the first pressure sensors are distributed in an array along the circumference of the center of the elastic spherical shell, two adjacent first pressure sensors are perpendicular to each other, the first pressure sensors are connected via a six-way support, and the center of the six-way support coincides with the center of the elastic spherical shell.

[0007] Preferably, the six interfaces of the six-way support are all connected to one end of the telescopic sleeve, a support plate is provided in the middle of the telescopic sleeve, the first pressure sensor is located on the side of the support plate away from the six-way support, and the other end of the telescopic sleeve is slidably connected to the inner wall of the elastic spherical shell.

[0008] Preferably, the telescopic sleeve is provided with a six-legged claw at one end close to the center of the ball, and ratchets are provided on the outer sides of the claws, and the inner wall of the interface is engaged with the ratchets.

[0009] Preferably, a limiting ring is provided at one end of the telescopic sleeve close to the elastic spherical shell, a double-cap nail is provided inside the telescopic sleeve, the nail head of the double-cap nail is provided with two layers of nail caps, the limiting ring is sleeved between the two layers of nail caps of the double-cap nail, the limiting ring can slide between the two layers of nail caps, and the nail body of the double-cap nail is fixedly connected to the elastic spherical shell.

[0010] Preferably, one end of the first pressure sensor contacts the support plate, and the other end contacts the head of the double-cap nail, and the first pressure sensor is continuously in a stress-bearing state.

[0011] Preferably, the Y-shaped air nozzle includes a main pipe and a branch pipe, one end of the main pipe is connected to the cavity, and the other end is connected to the inflation pipe through a one-way valve, the side wall of the main pipe is connected to one end of the branch pipe, and the other end of the branch pipe is connected to the deflation valve.

[0012] Preferably, the deflation valve includes a sleeve, which is detachably connected to the branch pipe, an elastic membrane is provided at one end of the sleeve close to the branch pipe, a filter is provided at one end of the sleeve away from the branch pipe, a puncture needle is provided on the side of the filter close to the elastic membrane, and the puncture needle is perpendicular to the filter.

[0013] Preferably, the elastic spherical shell includes two hemispherical shells, and the hemispherical shells are connected by mortise and tenon joints.

[0014] Preferably, a circle of tenons is provided at the edge of one of the hemispherical shells, and a circle of tenons is provided at the edge of the other hemispherical shell corresponding to the tenons, and steel bundles are provided in the two side walls of the tenons.

[0015] Preferably, a three-axis gravity direction measuring instrument is provided at the center of the six-way support.

[0016] Beneficial effects:

[0017] The utility model can simultaneously test the three-dimensional stress inside the soil body where the elastic spherical shell is located by arranging six first pressure sensors distributed in an array along the circumference of the center of the elastic spherical shell; and can be equivalent to the stress state of the soil body under different working conditions by inflating and pressurizing the inside of the elastic spherical shell, so that the detection is more comprehensive.

[0018] The utility model has ingenious structural design, is easy to operate and has broad application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the specific implementation methods of the utility model or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0020] Figure 1 It is a schematic diagram of the overall structure of the utility model;

[0021] Figure 2 This is a schematic diagram of the structure of the utility model in which a hemispherical shell is omitted;

[0022] Figure 3 This is a schematic diagram of the structure of the elastic spherical shell of the utility model in which the six-way support is omitted;

[0023] Figure 4 It is a schematic diagram of the cross-sectional structure of the utility model;

[0024] Figure 5 for Figure 4 The enlarged structural diagram at A in the middle;

[0025] Figure 6 It is a cross-sectional schematic diagram of the Y-shaped air nozzle in the utility model omitting the cylindrical hollow tube;

[0026] Figure 7 It is a cross-sectional schematic diagram of the air release valve in the utility model.

[0027] Description of reference numerals:

[0028] 1-elastic spherical shell, 101-hemispherical shell, 102-mortise, 103-tenon, 104-steel bundle, 2-Y-shaped air nozzle, 201-main pipe, 202-branch pipe, 203-columnar hollow pipe, 204-second pressure sensor, 3-six-way support, 301-interface, 4-telescopic sleeve, 401-claw, 402-support plate, 403-first pressure sensor, 404-limiting ring, 5-double-cap nail, 501-nail body, 502-nail cap, 6-three-axis gravity direction measuring instrument, 7-air release valve, 701-sleeve, 702-puncture needle, 703-crossbeam, 704-filter, 705-elastic membrane. DETAILED DESCRIPTION

[0029] The technical solution of the utility model will be clearly and completely described below in conjunction with the embodiments. Obviously, the described embodiments are part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments of the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0030] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise" and the like indicating directions or positional relationships are based on the directions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore should not be understood as a limitation on the present invention.

[0031] In addition, the terms "first" and "second" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present utility model, "multiple" means two or more, unless otherwise clearly and specifically defined. In addition, the terms "installed", "connected", and "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal connection of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present utility model can be understood according to specific circumstances.

[0032] Example 1

[0033] like Figure 1-Figure 7As shown, a spherical soil stress testing device includes an elastic spherical shell 1, a cavity is provided inside the elastic spherical shell 1, six first pressure sensors 403 are provided in the cavity, the first pressure sensors 403 are distributed in an array along the circumference of the center of the elastic spherical shell 1, and the force direction of the first pressure sensors 403 is along the diameter direction of the elastic spherical shell 1. Two adjacent first pressure sensors 403 are perpendicular to each other, and the first pressure sensors 403 are connected by a six-way support 3, and the center of the six-way support 3 coincides with the center of the elastic spherical shell 1. A three-axis gravity direction measuring instrument 6 is provided at the center of the six-way support 3. The three-axis gravity direction measuring instrument 6 can determine the direction of the elastic spherical shell 1 underground, confirm the angle between the first pressure sensor 403 and the three-axis gravity direction measuring instrument 6, clarify the measurement direction of each first pressure sensor 403, and facilitate recording the force direction of each first pressure sensor 403.

[0034] The six interfaces 301 of the six-way support 3 are all connected to one end of the telescopic sleeve 4. The telescopic sleeve 4 is provided with a six-legged claw 401 at the end close to the center of the ball. The outer sides of the claws 401 are provided with ratchets. The inner wall of the interface 301 engages with the ratchets. The side of the claw 401 close to the center of the ball is flat. The claw 401 can move toward the end away from the center of the ball. If the claw 401 needs to move toward the center of the ball, the staff needs to pinch the six-legged claw 401 to reduce the distance between adjacent claws 401, install the claw 401 into the interface 301, and pull the claw 401 to engage with the inner wall of the interface 301.

[0035] A support plate 402 is provided in the middle of the telescopic sleeve 4. The first pressure sensor 403 is located on the side of the support plate 402 away from the six-way support 3. A limit ring 404 is provided at one end of the telescopic sleeve 4 close to the elastic spherical shell 1. A double-cap nail 5 is provided inside the telescopic sleeve 4. The double-cap nail 5 is radially arranged along the elastic spherical shell 1. The head of the double-cap nail 5 is provided with two layers of nail caps 502. The limit ring 404 is sleeved between the two layers of nail caps 502 of the double-cap nail 5. The limit ring 404 can slide between the two layers of nail caps 502, which limits the movement trajectory of the telescopic sleeve 4. The nail body 501 of the double-cap nail 5 is fixedly connected to the elastic spherical shell 1. The end of the telescopic sleeve 4 close to the elastic spherical shell 1 can slide radially along the elastic spherical shell 1. One end of the first pressure sensor 403 contacts the support plate 402, and the other end contacts the head of the double-cap nail 5. The first pressure sensor 403 is continuously in a stressed state.

[0036] The elastic spherical shell 1 includes two hemispherical shells 101, and the hemispherical shells 101 are connected by mortise and tenon joints. A circle of tenons 103 is provided at the edge of one of the hemispherical shells 101, and a circle of tenons 102 is provided at the edge of the other hemispherical shell 101 corresponding to the tenons 103, and steel bundles 104 are provided in the two side walls of the tenon grooves 102. The steel bundles 104 are connected end to end along the edges of the hemispherical shells 101. When the inner cavity of the elastic spherical shell 1 is inflated, the hemispherical shells 101 expand outwards, and the steel bundles 104 can restrain the connection between the two hemispherical shells 101 to prevent the tenons 103 from coming out of the tenon grooves 102, thereby enhancing the sealing between the two hemispherical shells 101.

[0037] An air inlet can be provided on the elastic spherical shell 1 to facilitate the connection of the Y-shaped air nozzle 2. The air inlet can be directly provided on the surface of the hemispherical shell 101, or can be located at the connection of the two hemispherical shells 101. When the air inlet is located at the connection of the two hemispherical shells 101, the air inlet can be provided as two semicircular tubes, each of which is provided with a semicircular tube, and the two semicircular tubes are engaged to form an air inlet. A Y-shaped air nozzle 2 is provided on the elastic spherical shell 1, and the cavity is connected to the inflation pipe through the Y-shaped air nozzle 2. The Y-shaped air nozzle 2 includes a main pipe 201 and a branch pipe 202. One end of the main pipe 201 is sleeved on the outside of the air inlet and is connected to the cavity, and the other end is connected to the inflation pipe through a one-way valve, so as to facilitate the inflation of the cavity and change the internal air pressure of the elastic spherical shell 1; one end of the branch pipe 202 is connected to the side wall of the main pipe 201, and the other end of the branch pipe 202 is connected to the deflation valve 7. The deflation valve 7 includes a sleeve 701, which is detachably connected to the branch pipe 202, and the sleeve 701 and the branch pipe 202 can be connected by threads. An elastic membrane 705 is provided at one end of the sleeve 701 close to the branch pipe 202, and a filter screen 704 is provided at one end of the sleeve 701 away from the branch pipe 202. A crossbeam 703 is provided on the side of the filter screen 704 close to the elastic membrane 705, and both ends of the crossbeam 703 are connected to the inner wall of the sleeve 701. A puncture needle 702 is provided on the side of the crossbeam 703 close to the elastic membrane 705, and the puncture needle 702 is perpendicular to the filter screen 704. When the air pressure in the elastic spherical shell 1 is too high, the elastic membrane 705 is stretched toward the side of the filter screen 704, and the puncture needle 702 is sufficient to puncture the elastic membrane 705 to deflate and reduce the air pressure in the elastic spherical shell 1. The filter screen 704 has small holes, and under the action of water tension, it can filter soil particles well and only allow gas to pass. The crossbeam 703 plays a supporting role and can fix the position of the puncture needle 702.

[0038] A columnar hollow tube 203 is embedded on the outer wall of the main pipe 201, and the outer wall of the columnar hollow tube 203 is parallel to the outer wall of the main pipe 201. A second pressure sensor 204 is radially arranged inside the main pipe 201 corresponding to the columnar hollow tube 203. The hollowing of the hollow tube is smaller than the diameter of soil particles and only allows water to enter. The second pressure sensor 204 can detect the pore water pressure at the current position of the main pipe 201.

[0039] A temperature measuring meter and an air pressure measuring meter are arranged on the inner wall of the elastic spherical shell 1, which can detect the temperature of the current position of the elastic spherical shell 1 and the internal air pressure of the elastic spherical shell 1, so as to consider the influence of temperature on air pressure.

[0040] The first pressure sensor 403, the second pressure sensor 204, the temperature meter and the air pressure detector are all electrically connected to the controller, and the controller is used to receive and process the test results. The connection method here is a common technology in the field and will not be repeated here.

[0041] Working process:

[0042] Insert the telescopic sleeve 4 loaded with the first pressure sensor 403 into the interface 301 of the six-way support 3 in sequence. At this time, the staff needs to pinch the six-foot claws 401 to reduce the distance between adjacent claws 401, install the claws 401 into the interface 301, and then pull the claws 401 to engage with the inner wall of the interface 301 to ensure that the center of the six-way support 3 is located at the center of the ball;

[0043] Insert the tenon 103 of one hemispherical shell 101 into the tenon groove 102 of the other hemispherical shell 101 to ensure a stable connection and good air tightness of the elastic spherical shell 1, then sleeve the main pipe 201 outside the air inlet channel and connect the inflation pipe;

[0044] The assembled elastic spherical shell 1 is buried in a designated position, and air is inflated and pressurized into the elastic spherical shell 1 through an air-inflating pipe to expand it. After the surrounding soil is consolidated to the previous stress history state, the detection begins.

[0045] During the test, the pressure can be gradually increased according to the test requirements to measure the mechanical parameters of different soil mechanical states. The data of the first pressure sensor 403, the measurement data of the three-axis gravity direction measuring instrument 6, and the temperature and air pressure parameters in the cavity are transmitted to the controller on the ground.

[0046] After the test, the pressure can be increased further until the air pressure reaches the threshold value, and the elastic membrane 705 is stretched toward the side of the filter screen 704. The puncture needle 702 is sufficient to puncture the elastic membrane 705 to release the air and release the air pressure in the sphere. The elastic sphere can be taken out of the soil and reused.

[0047] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the utility model, rather than to limit it. Although the utility model has been described in detail with reference to the aforementioned embodiments, ordinary technicians in this field 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 with equivalents. However, these modifications or replacements do not make the essence of the corresponding technical solution deviate from the scope of the technical solution of the embodiments of the utility model.

Claims

1. A spherical soil stress testing device, characterized in that: It includes an elastic spherical shell, a cavity is provided inside the elastic spherical shell, a Y-shaped air nozzle is provided on the elastic spherical shell, the cavity is connected to the inflation pipe through the Y-shaped air nozzle, six first pressure sensors are provided in the cavity, the first pressure sensors are distributed in an array along the circumference of the center of the elastic spherical shell, two adjacent first pressure sensors are perpendicular to each other, the first pressure sensors are connected by a six-way support, and the center of the six-way support coincides with the center of the elastic spherical shell.

2. The spherical soil stress testing device according to claim 1, characterized in that: The six interfaces of the six-way support are all connected to one end of the telescopic sleeve. A support plate is provided in the middle of the telescopic sleeve. The first pressure sensor is located on the side of the support plate away from the six-way support. The other end of the telescopic sleeve is slidably connected to the inner wall of the elastic spherical shell.

3. The spherical soil stress testing device according to claim 2, characterized in that: The telescopic sleeve is provided with a six-legged claw at one end close to the center of the ball, and ratchets are provided on the outer sides of the claws, and the inner wall of the interface is engaged with the ratchets.

4. The spherical soil stress testing device according to claim 2, characterized in that: The telescopic sleeve is provided with a limiting ring at one end close to the elastic spherical shell, a double-cap nail is provided inside the telescopic sleeve, the double-cap nail head is provided with two layers of nail caps, the limiting ring is sleeved between the two layers of nail caps of the double-cap nail, the limiting ring can slide between the two layers of nail caps, and the double-cap nail body is fixedly connected to the elastic spherical shell.

5. The spherical soil stress testing device according to claim 4, characterized in that: One end of the first pressure sensor contacts the support plate, and the other end contacts the head of the double-cap nail, and the first pressure sensor is continuously in a stress state.

6. The spherical soil stress testing device according to claim 1, characterized in that: The Y-shaped air nozzle includes a main pipe and a branch pipe, one end of the main pipe is connected to the cavity, and the other end is connected to the inflation pipe through a one-way valve. The side wall of the main pipe is connected to one end of the branch pipe, and the other end of the branch pipe is connected to the deflation valve.

7. The spherical soil stress testing device according to claim 6, characterized in that: The deflation valve includes a sleeve, which is detachably connected to the branch pipe, an elastic membrane is provided at one end of the sleeve close to the branch pipe, a filter is provided at one end of the sleeve away from the branch pipe, a puncture needle is provided on the side of the filter close to the elastic membrane, and the puncture needle is perpendicular to the filter.

8. The spherical soil stress testing device according to claim 1, characterized in that: The elastic spherical shell comprises two hemispherical shells, and the hemispherical shells are connected by mortise and tenon joints.

9. The spherical soil stress testing device according to claim 8, characterized in that: A circle of tenons is arranged at the edge of one of the hemispherical shells, and a circle of tenon grooves is arranged at the edge of the other hemispherical shell corresponding to the tenons, and steel bundles are arranged in the two side walls of the tenon grooves.

10. The spherical soil stress testing device according to claim 1, characterized in that: A three-axis gravity direction measuring instrument is arranged at the center of the six-way support.

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