Built-in cementing material internal stress testing device and method

Abstract

The invention discloses a built-in cementing material internal stress testing device and method, the testing device comprises a spherical shell, a direction adjusting assembly, a central integration assembly and a stress testing element, the spherical shell is internally provided with a pair of supporting grooves which are centrally symmetrically arranged along the horizontal direction; the direction adjusting assembly comprises a first direction adjusting circular ring and a second direction adjusting circular ring of which the symmetry axes are perpendicular to each other; the first direction adjusting circular ring is rotationally connected with a supporting groove in the spherical shell; the central integrated assembly comprises a stand column rotationally arranged in the second direction adjusting ring and a spherical crown body fixedly arranged on the lower portion of the stand column, and the stand column is perpendicular to the plane where the first direction adjusting ring is located. The stress test element is installed in the central integrated assembly. According to the invention, automatic orientation and positioning of the stress sensor in the pouring and consolidation process of the cementing material are realized, and the stress sensor is in full contact with the cementing material, so that stress data in corresponding directions in the cementing material are accurately measured, and a more accurate data measurement method and device are provided for corresponding research.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of stress testing of cementitious materials, and particularly relates to an internal stress testing device and method for cementitious materials. BACKGROUND

[0002] There are various types of cementitious materials (such as concrete, cement mortar, cement, gypsum, etc.) in China, which are widely used in the fields of water conservancy, construction, transportation, new energy, etc. With the increase of the service time of these cementitious material structures, the requirements for their operation performance and maintenance are also increasing. As the basis for post-operation management, the internal stress condition of cementitious materials is particularly important. The existing technology has matured for how to measure the external stress data of cementitious material structures, but there are still great difficulties in how to measure the internal stress data thereof.

[0003] At present, there are mainly three methods for measuring the internal stress data of cementitious materials. The first method is to set a reinforcing body such as a steel bar in the cementitious material, and to paste a stress sensor on the reinforcing body. This method utilizes the good bonding performance and similar linear expansion coefficient principle between the reinforcing body and the cementitious material, and indirectly reflects the stress condition of the cementitious material by measuring the stress data of the reinforcing body. The main problems of this method are: (1) the reinforcing body has different material properties from the cementitious material, and indirect testing of the reinforcing body is easy to cause stress deviation; (2) the stress sensor needs to be connected to a data acquisition terminal by an external data line, but the data line is easy to be damaged during the pouring and vibrating of the cementitious material, thereby causing the stress sensor to fail, and too many external data lines are also easy to damage the integrity of the cementitious material after solidification, thereby reducing the overall strength and causing measurement errors, and failing to truly reflect the structural performance.

[0004] The second method is based on the first method, and uses a wireless transmission stress sensor to avoid the problem of stress sensor failure due to the pouring and vibrating of the cementitious material. However, since the stress sensor is still directly attached to the reinforcing body such as a steel bar, the stress measurement error caused by the different material properties cannot be overcome, and the main defect of this method is that the internal stress data of the cementitious material cannot be flexibly measured.

[0005] The third method is to reserve a hole when pouring the cementitious material structure, and then paste a stress sensor at the hole after the cementitious material has a certain strength. This method needs to reserve a hole on the cementitious material structure, thereby affecting the integrity of the cementitious material structure, and for large-volume cementitious material structures, the operation of this method is very complex, and the reserved hole can only be close to the outer surface of the structure, and cannot be deep into the internal structure for stress measurement. SUMMARY

[0006] In order to solve the above problems, the present application provides an internal stress testing device and method for cementitious materials.

[0007] The built-in cementitious material internal stress testing device comprises a spherical shell, the inside of the spherical shell has a pair of support grooves arranged symmetrically along the horizontal direction; a direction adjusting assembly, the direction adjusting assembly comprises a first direction adjusting ring and a second direction adjusting ring, the symmetry axes of the first direction adjusting ring and the second direction adjusting ring are perpendicular to each other, and the plane where the first direction adjusting ring is located is perpendicular to the plane where the second direction adjusting ring is located, wherein the first direction adjusting ring is rotationally connected with the support grooves in the inside of the spherical shell, and the second direction adjusting ring is rotationally arranged in the inside of the first direction adjusting ring; a central integrated assembly, the central integrated assembly comprises a column rotationally arranged in the inside of the second direction adjusting ring and a spherical cap fixedly arranged at the lower part of the column, and the length direction of the column is perpendicular to the plane where the first direction adjusting ring is located; and a stress testing element, the stress testing element is installed in the central integrated assembly.

[0008] Two first connecting rods are symmetrically arranged along the symmetry axis direction of the outer periphery of the first direction adjusting ring, the first connecting rods are installed in the support grooves in the inside of the spherical shell, and the first connecting rods are rotationally connected with the support grooves; the two first connecting rods of the first direction adjusting ring are arranged along a first preset direction, two first through holes are symmetrically formed on the outer periphery of the first direction adjusting ring along a second preset direction, and the second preset direction is perpendicular to the first preset direction.

[0009] Two second connecting rods are symmetrically arranged along the symmetry axis direction of the outer periphery of the second direction adjusting ring, the second connecting rods are matched with the first through holes, and the second connecting rods are rotationally connected with the first through holes; the two second connecting rods of the second direction adjusting ring are arranged along the second preset direction, two second through holes are symmetrically formed on the outer periphery of the second direction adjusting ring along a third preset direction, the third preset direction is perpendicular to the first preset direction and the second preset direction, and the third preset direction is consistent with the length direction of the column.

[0010] Third connecting rods are arranged at both ends of the column, the third connecting rods are matched with the second through holes, and the third connecting rods are rotationally connected with the second through holes.

[0011] The spherical cap and the column adopt an integrated forming mechanism, the inside of the spherical cap is hollow, the planar side of the spherical cap faces upward, and the curved side of the spherical cap faces downward.

[0012] The stress testing element comprises a sealed shell located in the inside of the spherical cap, the sealed shell is fixed to the inner wall of the spherical cap, and a signal transmitter, a positioning chip, a storage chip and a plurality of data lines are arranged in the inside of the sealed shell, and the signal transmitter is connected with the positioning chip and the storage chip respectively.

[0013] The stress testing element further comprises stress sensors, the stress sensors comprise vertical stress sensors uniformly distributed on the outer surface of the column and horizontal stress sensors on the planar side of the spherical cap, and the stress sensors are bidirectionally connected with the signal transmitter and the storage chip through the reserved data lines.

[0014] The use method of the built-in cementitious material internal stress testing device of the application comprises the following steps:

[0015] S1: According to the geometric size of the cementitious material structure and the internal force testing requirement, the measuring point position is set in advance, and the testing device is placed at the measuring point position;

[0016] S2: After the cementitious material is uniformly stirred according to the design mixing ratio, the pouring is started according to the design requirement, and the cementitious material is fully vibrated during the pouring process to ensure that the cementitious material is filled and dense;

[0017] S3: Accompanying the pouring of the cementitious material, the testing device is rotated through the steering assembly, so that the central integrated assembly always maintains a vertical state, and before the initial setting of the cementitious material, the spherical shell, the first steering ring and the second steering ring of the testing device gradually dissolve, and the internal stress sensor of the testing device is integrated with the cementitious material;

[0018] S4: After the cementitious material is completely set and the curing is completed, the data acquisition of the testing device is started, the accurate positioning of the testing point position is realized through the positioning chip, and the stress data stored in the storage chip is transmitted to the data collector through the signal transmitter;

[0019] S5: According to the collected sensor data, the stress of each testing point position in the cementitious material structure is calculated and analyzed in real time.

[0020] The spherical shell, the first steering ring and the second steering ring are made of easily soluble material, and the proportion of the components in the easily soluble material is adjusted, so that the dissolution time of the spherical shell, the first steering ring and the second steering ring after being placed in the cementitious material is 10-20 minutes earlier than the initial setting time of the cementitious material.

[0021] The column and the spherical crown body are made of a material having physical and chemical stability, being insoluble in the cementitious material and having good adhesion with the cementitious material.

[0022] The beneficial effects of the application are,

[0023] 1、The stress sensor is arranged on the spherical crown body and the column, compared with the traditional stress detection device and detection method, the stress sensor is directly and fully contacted with the cementitious material without damaging the structure of the cementitious material component, so that the corresponding direction stress data in the cementitious material is more accurately measured, and a more accurate data measurement method and device are provided for the corresponding research;

[0024] 2、The application solves the defect that the device fails due to the damage of the wire during the vibrating process caused by the wire leading out in the traditional wired stress measurement device, and ensures the integrity of the experimental data by setting the signal transmitter, positioning chip and storage chip in the spherical cap body, compared with the traditional wired stress measurement device.

[0025] 3、The application realizes the self-orientation positioning built-in stress testing device without paying attention to the device placement form during the arrangement process, which greatly reduces the workload, compared with the traditional stress detection device arrangement process which needs to pay attention to the arrangement direction of the stress sensor and cannot guarantee the arrangement direction of the stress sensor after vibrating.

[0026] 4、For large-volume cementitious material components such as dams and large piles, the application can determine the specific position of the stress sensor inside the structure after the installation of the traditional measurement equipment, and can display the position of the stress sensor on the computer by scanning the poured component as a whole after the component pouring is completed, compared with the disadvantage that the stress sensor cannot be located inside the structure after the installation of the traditional measurement equipment.

[0027] 5、The spherical shell and the direction adjusting ring of the application are made of water-soluble materials, which can prevent the data line from being damaged during vibrating, compared with the traditional wireless internal force detection device. BRIEF DESCRIPTION OF DRAWINGS

[0028] Figure 1 is a structural schematic diagram of the built-in cementitious material internal stress testing device of the application.

[0029] Figure 2 is a structural schematic diagram of the central integrated assembly of the application.

[0030] Figure 3 is a schematic diagram of the arrangement position of the horizontal stress sensor of the application.

[0031] Figure 4 is a distribution diagram of the stress testing elements inside the spherical cap body of the application.

[0032] Figure 5 is a structural schematic diagram of the first direction adjusting ring of the application.

[0033] Figure 6 is a structural schematic diagram of the second direction adjusting ring of the application.

[0034] Figure 7 is an effect diagram of measuring the peripheral cement mortar pile material internal force in the cement mortar pile of Example 1 of the application.

[0035] Figure 8 This is a diagram showing the effect of measuring the internal stress of a large-volume cementitious material structure in Embodiment 2 of the present invention.

[0036] Figure 9 This is a diagram showing the effect of measuring the internal stress of cementitious materials in a small-volume cementitious material component in Embodiment 3 of the present invention.

[0037] Figure label:

[0038] 1. Spherical shell; 2. Spherical crown; 3. Vertical stress sensor; 4. First connecting rod; 5. Third connecting rod; 6. Column; 7. First adjusting ring; 8. Second connecting rod; 9. Second adjusting ring; 10. Horizontal stress sensor; 11. Sealed shell; 12. Second through hole; 13. First through hole; 14. Signal transmitter; 15. Storage chip; 16. Positioning chip; 17. Cement mortar expansion material; 18. Connecting steel wire; 19. Precast concrete pile with inner core; 20. Embedded fixing pin; 21. Cast cementitious material; 22. Vertical positioning steel wire; 23. Precast steel cage; 24. Precast template. Detailed Implementation

[0039] Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0040] like Figures 1-9 As shown, the built-in cementitious material internal stress testing device of the present invention includes: a spherical shell 1, an adjusting assembly, a central integrated assembly, and a stress testing element. The spherical shell 1 has a pair of support grooves centrally symmetrically arranged along a horizontal direction inside. The adjusting assembly includes a first adjusting ring 7 and a second adjusting ring 9 whose axes of symmetry are perpendicular to each other; that is, the plane of the first adjusting ring 7 is perpendicular to the plane of the second adjusting ring 9. The first adjusting ring 7 is rotatably connected to the support groove inside the spherical shell 1, meaning the first adjusting ring 7 can rotate relative to the support groove within the spherical shell 1. The second adjusting ring 9 is rotatably disposed inside the first adjusting ring 7; that is, the second adjusting ring 9 is located inside the first adjusting ring 7, and the second adjusting ring 9 can rotate relative to the first adjusting ring 7. The central integrated assembly includes a column 6 rotatably disposed inside the second aligning ring 9 and a spherical cap 2 fixedly disposed at the lower part of the column 6, with the length direction of the column 6 perpendicular to the plane of the first aligning ring 7; the column 6 coincides with one of the axes of symmetry of the second aligning ring 9, and can be regarded as the column 6 and the second aligning ring 9 being located in the same plane, and the column 6 being able to rotate relative to the second aligning ring 9. Stress testing elements are installed in the central integrated assembly.

[0041] The second aligning ring 9 is located inside the first aligning ring 7, and the first aligning ring 7 is located inside the spherical shell 1. That is, the inner diameter of the second aligning ring 9 is smaller than the inner diameter of the first aligning ring 7, and the inner diameter of the first aligning ring 7 is smaller than the inner diameter of the spherical shell 1.

[0042] Two first connecting rods 4 are symmetrically arranged on the outer periphery of the first adjusting ring 7 along one of its axes of symmetry. The first connecting rods 4 are installed in a support groove inside the spherical outer shell 1, and are rotatably connected to the support groove. The two first connecting rods 4 of the first adjusting ring 7 are arranged along a first preset direction. Two first through holes 13 are symmetrically opened on the outer periphery of the first adjusting ring 7 along a second preset direction, which is perpendicular to the first preset direction. Alternatively, the axis of symmetry of the two first connecting rods 4 is perpendicular to the axis of symmetry of the two first through holes 13.

[0043] Two second connecting rods 8 are symmetrically arranged on the outer periphery of the second adjusting ring 9 along one of its axes of symmetry. Each second connecting rod 8 engages with a first through hole 13 and is rotatably connected to the first through hole 13. This means that the two second connecting rods 8 can be inserted into the two first through holes 13 respectively, and can rotate relative to the first through holes 13. The two second connecting rods 8 of the second adjusting ring 9 are arranged along a second preset direction, meaning the direction of the axis of symmetry of the two second connecting rods 8 is the same as the direction of the axis of symmetry of the two first through holes 13. Two second through holes 12 are symmetrically opened on the outer periphery of the second adjusting ring 9 along a third preset direction. The third preset direction is perpendicular to both the first and second preset directions, and is consistent with the length direction of the column 6. The first and second preset directions are in the same plane, and the second and third preset directions are in the same plane. Specifically, as shown... Figure 1 As shown, when the first preset direction is set along the Y-axis, the second preset direction is set along the X-axis, and the third preset direction is set along the Z-axis.

[0044] The column 6 is provided with a third connecting rod 5 at both ends. The third connecting rod 5 cooperates with the second through hole 12 and is rotatably connected to the second through hole 12. That is to say, the two third connecting rods 5 can be inserted into the two second through holes 12 respectively, and the third connecting rod 5 can rotate relative to the second through hole 12. In other words, the column 6 can rotate in the second adjusting ring 9.

[0045] like Figure 1 and Figure 2 As shown, the spherical crown 2 and the column 6 are integrally molded, meaning that the spherical crown 2 and the column 6 are cast in one piece using a mold, forming a stable whole without relative displacement. The hollow interior of the spherical crown 2 is located at the lower end of the column 6, with the flat side of the spherical crown 2 facing upwards and the curved side facing downwards.

[0046] The stress testing element includes a stress sensor and a sealed housing 11 fixed to the inner wall of the spherical cap 2. Inside the sealed housing 11 are a signal transmitter 14, a positioning chip 16, a storage chip 15, and multiple data lines. The signal transmitter 14 is connected to the positioning chip 16 and the storage chip 15 to achieve wireless signal transmission and positioning of the entire testing device. The positioning chip 16 allows for precise positioning of the measuring device through a subsequent overall scan of the cementitious material component using a positioning device.

[0047] The stress sensors include vertical stress sensors 3 uniformly distributed on the outer surface of the column 6 and horizontal stress sensors 10 on the planar side of the spherical cap 2.

[0048] One to three vertical stress sensors 3 are attached to the surface of the column 6, and four to eight horizontal stress sensors 10 are attached to the planar side surface of the spherical cap 2. The horizontal stress sensors 10 are attached radially and form a circle. The stress sensors are bidirectionally connected to the signal transmitter 14 and the storage chip 15 inside the spherical cap 2 through a reserved data line to realize the real-time transmission and storage of measurement data.

[0049] The orientation components and the spherical cap, along with the device's own weight, ensure that the column 6 of the central integrated component always maintains a vertical orientation, thereby enabling the measuring device to perform self-orientation. This ensures that the vertical stress sensor 3 on the surface of the column 6 collects the vertical internal force of the measured cementitious material, and the horizontal stress sensor 10 on the plane side of the spherical cap 2 collects the horizontal internal force of the measured cementitious material, thus avoiding measurement errors caused by sensor orientation deviation.

[0050] The spherical shell 1, the first aligning ring 7, and the second aligning ring 9 are made of easily soluble materials. The composition and proportion of the water-soluble materials are adjusted so that the dissolution time of the spherical shell 1, the first aligning ring 7, and the second aligning ring 9 after being placed in the cementitious material is 10-20 minutes earlier than the initial setting time of the cementitious material. This allows the stress sensor to directly contact the solidified cementitious material, improving the accuracy of internal force measurement.

[0051] Specifically, the cementing material can be an organic cementing material or an inorganic cementing material. When the cementing material is an inorganic cementing material, the soluble material used to make the spherical shell 1, the first orienting ring 7, and the second orienting ring 9 is a water-soluble material, specifically water-soluble polyvinyl alcohol (PVA). Sodium sulfate or ultrafine silica can be added to the PVA material to shorten or prolong the dissolution time of the PVA material.

[0052] When the cementing material is an organic cementing material, the easily soluble material used to make the spherical shell 1, the first orienting ring 7, and the second orienting ring 9 is low-melting-point paraffin wax. At the same time, polyethylene wax or white oil can be added to the paraffin wax to prolong or shorten the dissolution time of the paraffin wax.

[0053] The column 6 and the spherical crown 2 are made of a material that has physical and chemical stability, is insoluble in cementing materials, and has good adhesion to cementing materials.

[0054] The materials used to make the column 6 and the spherical crown 2 can be alumina ceramic or silicon oxide ceramic.

[0055] The spherical outer shell 1 has a diameter of 2-5 cm to accommodate the aggregate particle size of the cementitious material, preventing the entire testing device from shifting due to excessive size being squeezed by the aggregate during the cementitious material pouring and vibration process, or from being too small to accommodate the internal integrated structure. Furthermore, the spherical outer shell 1 is composed of two hemispheres joined together by adhesive or snap-fit ​​methods, which are existing technologies and will not be described in detail here.

[0056] The method of using the built-in cementitious material internal stress testing device of the present invention includes the following steps:

[0057] S1: Based on the geometric dimensions and internal force testing requirements of the cementitious material structure, the test point positions are pre-set, and the built-in cementitious material internal stress testing device (hereinafter referred to as the test device) is placed at the test point positions to avoid excessive displacement of the test device during cementitious material pouring;

[0058] S2: After the cementitious material is mixed evenly according to the design mix ratio, pouring begins according to the design requirements. During the pouring process, the cementitious material is vibrated thoroughly to ensure that it is filled densely.

[0059] S3: As the cementitious material is poured, the test device rotates through the directional component to keep the central integrated component in a vertical position. Before the cementitious material initially sets, the spherical shell 1, the first directional ring 7, and the second directional ring 9 of the test device gradually dissolve, causing the stress sensor inside the test device to solidify with the cementitious material.

[0060] S4: After the cementitious material has solidified and cured, data acquisition of the testing device begins. The positioning chip enables precise positioning of the test points, and the stress data stored in the storage chip is transmitted to the data acquisition unit via the signal transmitter.

[0061] S5: Based on the collected sensor data, perform real-time calculation and analysis of the stress at each test point inside the cementitious material structure.

[0062] In the specific casting process, in order to suppress the floating of the test device, multiple test devices are connected together by connecting steel wires. Specifically, it is necessary to open through holes as needed near the two support grooves in the spherical shell or near the top and bottom of the spherical shell, and tie the end of the steel wire rope into the through hole so that multiple test devices can be connected together.

[0063] Example 1

[0064] like Figure 7 As shown, this embodiment illustrates the specific application of an internal stress testing device for embedded cementitious materials in cement mortar expanded piles. The aim is to accurately measure the internal stress of the cement mortar expanded material surrounding the pile body using the device's self-orienting function. The specific implementation steps are as follows:

[0065] S1: Multiple built-in cementitious material internal stress testing devices are connected in sequence by connecting steel wire 18, with adjacent measuring devices spaced 1 meter apart, and assembled into a chain measuring device.

[0066] S2: Use pre-embedded fixing pins 20 to fix the chain test device to the pile end and pile head of the inner core precast concrete pile 19 respectively. The fixing pins 20 are made of high-strength alloy steel to ensure that they do not loosen or break during the sinking of the pile.

[0067] S3: Mix cement mortar expansion material 17 according to the design mix ratio;

[0068] S4: Drill the pile hole according to the predetermined pile driving position. The pile hole size is 200mm larger than the outer diameter of the inner core precast concrete pile 19. Then pour the cement mortar expansion material 17 into the drilled pile hole until the design elevation is reached.

[0069] S5: Use lifting equipment to slowly sink the precast concrete pile 19 with chain device into the bottom of the pile hole. During the sinking process, ensure that the pile body sinks into the pile hole vertically and coaxially. Avoid the grout disturbance caused by excessive speed, which may cause the measuring device to be squeezed and damaged.

[0070] S6: After the cement mortar expansion material 17 inside and outside the pile hole has been cured to the design strength, a cement mortar expansion pile composed of an inner core precast concrete pile 19 and cement mortar expansion material 17 is formed. The data acquisition system is started, the measuring device is positioned by the positioning chip 16, the position distribution map of the testing device in the cement mortar expansion pile is generated on the computer terminal, and the data in the storage chip 15 is received for later analysis.

[0071] Compared with traditional stress testing devices, the chain measuring device in this embodiment has the advantages of easy positioning, no need to pay attention to the shape of the device, minimal impact on the internal structure of cementitious materials, and stable device performance.

[0072] Example 2

[0073] like Figure 8 As shown, this embodiment illustrates the specific application of an embedded cementitious material internal stress testing device in large-volume cementitious material structures such as large foundations and dam foundations. Considering the characteristics of large-volume structures requiring reinforcing cages and large pour volumes, a chain-type measuring device is employed. The specific implementation steps are as follows:

[0074] S1: Based on the internal force testing requirements of large-volume cementitious material structures, determine the number and location of internal stress testing points for large-volume cementitious material structures; connect multiple built-in cementitious material internal stress testing devices in sequence through connecting steel wire 18 to form a chain-type self-orienting positioning built-in cementitious material internal stress testing device, which is a chain-type measuring device.

[0075] S2: Clean the surface of the pre-installed steel cage 23 of debris, and use the vertical positioning steel wire 22 to tie the chain measuring device to the pre-installed steel cage 23;

[0076] S3: The pre-installed steel cage 23 with the chain measuring device is hoisted as a whole into the casting form of the large-volume component. Then the form is closed and the sealing of the form is checked to prevent grout leakage during casting.

[0077] S4: During the first pour, pour cementitious material 21 into the formwork to a height not exceeding 50 cm and vibrate it thoroughly;

[0078] S5: In subsequent layered pouring, before the initial setting of the next layer of cementitious material 21, the pouring and vibration of the previous layer of cementitious material 21 shall be carried out. The height of each layer of cementitious material 21 shall not exceed 50 cm. Repeat the above operation until the large-volume cementitious material component is poured.

[0079] S6: After the pouring is completed, the large-volume cementitious material components shall be cured for no less than 28 days. At the same time, the signal transmission status of the chain measuring device shall be initially detected by the signal transmitter 14 to ensure that the storage chip 15 can record data normally.

[0080] S7: After maintenance is completed, the data acquisition system is used to receive signals from the positioning chip 16 built into each measuring device, generate a location distribution map of the chain measuring devices on the computer terminal, and receive the measurement data in the storage chip 15 for subsequent analysis.

[0081] In step S2 of this embodiment, the use of vertical positioning steel wire 22 to bind the chain measuring device can not only fix the chain measuring device in the designated position, but also prevent the chain measuring device from floating after the large-volume cementitious material component is poured, thus ensuring the accuracy of data measurement.

[0082] Compared with traditional stress testing devices, the built-in internal stress testing device for cementitious materials used in this embodiment solves the problems of being unable to control the position and shape of the stress sensor in the cementitious material, and the data cable being easily damaged during vibration, which can cause the device to fail. At the same time, it ensures the integrity of the cementitious material component structure and the accuracy of the measured data.

[0083] Example 3

[0084] like Figure 9As shown in the figure, this embodiment illustrates the specific application method of the built-in cementitious material internal stress testing device in small-volume cementitious material components such as small precast blocks and laboratory test blocks. Taking advantage of the ease of casting small-volume components, the measuring device is deployed using a throwing method, simplifying the operation process while ensuring testing accuracy. The specific implementation steps are as follows:

[0085] S1: Mark 5 to 6 throwing points at the bottom of the casting template of small volume components, i.e. the bottom of the pre-set template 24, according to the test requirements, to ensure that the center and edge areas of the components are covered.

[0086] S2: Manually throw the built-in cementitious material internal stress testing device into the pre-set template 24, so that the testing device is placed at the marked throwing point;

[0087] S3: After the pouring is completed, pour cementitious material 21 into the pre-set template 24 until the pouring height reaches the design elevation of the template, and vibrate it thoroughly; after vibration, observe whether there is any water bleeding on the surface of the poured cementitious material 21. If so, remove it in time to ensure that the surface of the component is flat.

[0088] S4: After pouring, place the small-volume components in a standard curing environment for 28 days; during the curing period, regularly observe the surface of the components to avoid cracks.

[0089] S5: After maintenance is completed, the data acquisition system is used to receive signals from the positioning chips 16 built into each measuring device, generate a location distribution map of the measuring devices on the computer terminal, and receive data from the storage chip 15 for subsequent analysis.

[0090] Compared with traditional stress testing devices, the built-in cementitious material internal stress testing device used in this embodiment has the advantages of higher data measurement accuracy, more convenient device installation, less impact on the cementitious material component structure, and more intuitive measurement data results.

[0091] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0092] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0093] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, an electrical connection, or a connection that allows communication between them; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0094] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "over," and "on top" of the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0095] In this invention, the terms "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to a specific feature, structure, material, or characteristic described in connection with that embodiment or example, which is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0096] Although the above embodiments have been shown and described, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Any changes, modifications, substitutions and variations made to the above embodiments by those skilled in the art are within the protection scope of the present invention.

Claims

1. A built-in device for testing internal stress in cementitious materials, characterized in that, include: A spherical shell, wherein the interior of the spherical shell has a pair of support grooves that are centrally symmetrically arranged along the horizontal direction; The directional assembly includes a first directional ring and a second directional ring whose axes of symmetry are perpendicular to each other, and the plane on which the first directional ring is located is perpendicular to the plane on which the second directional ring is located. The first directional ring is rotatably connected to a support groove inside the spherical shell, and the second directional ring is rotatably disposed inside the first directional ring. The central integration component includes a column rotatably disposed inside the second directional ring and a spherical cap fixedly disposed at the lower part of the column, wherein the length direction of the column is perpendicular to the plane where the first directional ring is located. A stress testing element, which is installed in a central integrated assembly.

2. The built-in cementitious material internal stress testing device according to claim 1, characterized in that, Two first connecting rods are symmetrically arranged on the outer periphery of the first directional ring along its axis of symmetry. The first connecting rods are installed in the support groove inside the spherical shell and are rotatably connected to the support groove. The two first connecting rods of the first directional ring are arranged along a first preset direction. Two first through holes are symmetrically opened on the outer periphery of the first directional ring along a second preset direction. The second preset direction is perpendicular to the first preset direction.

3. The built-in cementitious material internal stress testing device according to claim 2, characterized in that, Two second connecting rods are symmetrically arranged on the outer periphery of the second adjusting ring along its axis of symmetry. The second connecting rods cooperate with the first through hole and are rotatably connected to the first through hole. The two second connecting rods of the second adjusting ring are arranged along a second preset direction. Two second through holes are symmetrically opened on the outer periphery of the second adjusting ring along a third preset direction. The third preset direction is perpendicular to the first and second preset directions and is consistent with the length direction of the column.

4. The built-in cementitious material internal stress testing device according to claim 3, characterized in that, The column is provided with a third connecting rod at both ends. The third connecting rod is engaged with the second through hole and is rotatably connected to the second through hole.

5. The built-in cementitious material internal stress testing device according to claim 1, characterized in that, The spherical crown and the column are integrally formed. The spherical crown is hollow inside, with the flat side facing up and the curved side facing down.

6. The built-in cementitious material internal stress testing device according to claim 1, characterized in that, The stress testing element includes a sealed housing fixed to the inner wall of the spherical crown. Inside the sealed housing are a signal transmitter, a positioning chip, a storage chip, and multiple data lines. The signal transmitter is connected to the positioning chip and the storage chip, respectively.

7. The built-in cementitious material internal stress testing device according to claim 6, characterized in that, The stress testing element also includes a stress sensor, which includes a vertical stress sensor evenly distributed on the outer surface of the column and a horizontal stress sensor on the planar side of the spherical cap. The stress sensor is bidirectionally connected to the signal transmitter and the storage chip via a data line.

8. A method of using the built-in cementitious material internal stress testing device according to claim 1, characterized in that, Includes the following steps: S1: Based on the geometric dimensions and internal force testing requirements of the cementitious material structure, the measuring point positions are pre-set, and the testing device is placed at the measuring point positions; S2: After the cementitious material is mixed evenly according to the design mix ratio, pouring begins according to the design requirements. During the pouring process, the cementitious material is vibrated thoroughly to ensure that it is filled densely. S3: As the cementitious material is poured, the test device rotates through the directional component to keep the central integrated component in a vertical position. Before the cementitious material initially sets, the spherical shell, the first directional ring, and the second directional ring of the test device gradually dissolve, allowing the stress sensor inside the test device to come into direct and full contact with the cementitious material. S4: After the cementitious material has solidified and cured, data acquisition of the testing device begins. The positioning chip enables precise positioning of the test points, and the stress data stored in the storage chip is transmitted to the data acquisition unit via the signal transmitter. S5: Based on the collected sensor data, perform real-time calculation and analysis of the stress at each test point inside the cementitious material structure.

9. The method of using the built-in cementitious material internal stress testing device according to claim 8, characterized in that, The spherical shell, the first aligning ring, and the second aligning ring are made of easily soluble materials, and the dissolution time of the spherical shell, the first aligning ring, and the second aligning ring after being placed in the cementitious material is 10-20 minutes earlier than the initial setting time of the cementitious material.

10. The method of using the built-in cementitious material internal stress testing device according to claim 8, characterized in that, The columns and spherical crowns are made of materials that are physically and chemically stable, insoluble in cementing materials, and have good adhesion to cementing materials.

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