Self-balancing hoop device for hydraulic loading test of shield tunnel prototype segments

Abstract

The present invention discloses a self-balancing hoop device for use in a hydrostatic loading test of a prototype segment of a shield tunnel. The device comprises a hoop beam, prestressed tendons, and a jack. The hoop beam comprises two opposing vertical side panels, one of which has anchor holes at its upper and lower portions and a central cable hole at its middle portion. The other side panel has branch cable holes at its upper and lower portions and a cable hole at its middle portion. A jack is mounted outside the cable hole in the hoop beam. One end of two sets of prestressed tendons are connected to the two anchor holes, respectively. The other ends of the two sets of prestressed tendons pass through the two branch cable holes, then pass through the central cable hole, and then pass through the cable hole to connect to the jack's push rod. By replacing the traditional two jacks on the same hoop beam with one, and connecting one end of the two sets of prestressed tendons to the same jack's push rod, the present invention improves the rationality of the force and loading capacity of the entire hoop device, thereby meeting the loading requirements of ultra-large cross-sections and ultra-high water pressures.

Description

Technical Field

[0001] The invention relates to a water pressure loading test device for a shield tunnel prototype segment, in particular to a self-balancing hoop device used for a water pressure loading test for a shield tunnel prototype segment. Background Art

[0002] In large-scale underwater shield tunnel projects, segments, the prefabricated lining structure of the shield tunnel, can severely impact construction and operation if damaged, making repair extremely difficult. Therefore, research on their stress and damage characteristics is crucial. Testing prototype segments under hydraulic loading can demonstrate the effects of hydraulic pressure on the tunnel structure, providing a reliable test basis for underwater shield tunnel structural design and construction.

[0003] The basic principle of the hydrostatic loading test for prototype segments of shield tunnels is to surround multiple groups of prestressed tendons (preferably steel strands) on the circumferential outer wall of a prototype segment assembled into a cylindrical shape. One end of each group of prestressed tendons is fixed through an anchor hole on a hoop beam, and the other end of each group of prestressed tendons is fixed through a top rod of a jack mounted on the hoop beam. By adjusting the extension length of the top rod of the jack, the prestressed tendons can be tightened or loosened to adjust the pressure of the prestressed tendons on the outer wall of the prototype segment, thereby simulating different water pressures on the prototype segment. The hoop beam, prestressed tendons, and jacks constitute a hoop device for the hydrostatic loading test of prototype segments of shield tunnels. The basic structure of the hoop beam is to connect a horizontal top plate, a horizontal bottom plate, and three or four vertical side plates. Each plate is preferably made of metal plate, such as steel plate, and the connection method is generally welding, wherein two opposing side plates are provided with through holes.

[0004] like Figure 1 and Figure 2 As shown in the figure, in the conventional hoop device for the hydrostatic loading test of the prototype segment of the shield tunnel, four vertically distributed side plate through-holes 2 are respectively provided on the two opposite and vertical side plates of the hoop beam 1, and two jacks 4 are installed on one hoop beam 1; when in use, one end of a set of prestressed tendons 3 is anchored to the corresponding side plate through a side plate through-hole 2, and the other end passes through the corresponding side plate through-hole 2 on the other side plate and is then fixed on the prototype segment ( Figure 1 and Figure 2 Not shown, reference Figure 6 The prestressed tendons 3 are connected to the other jack 4 in a similar manner except that they pass through different side plate through holes 2. By adjusting the extension length of the top rod of the jack 4, the pressure of the prestressed tendons 3 on the outer wall of the prototype segment can be adjusted, thereby simulating the different water pressures on the prototype segment.

[0005] In order to improve the overall force balance of the prototype segment and better complete the simulation test, it is necessary to keep the loading force of the prestressed tendons 3 on the single hoop beam 1 as balanced as possible, that is, the tension of the two jacks 4 on the two groups of prestressed tendons 3 should be as equal as possible. The specific force analysis is as follows: Take a single jack 4 and the corresponding prestressed tendons 3 (i.e. Figure 2 Looking at the upper or lower half of hoop beam 1, F1a and F1b are equal in magnitude and opposite in direction, while F2a and F2b are equal in magnitude and opposite in direction. However, F1a and F1b, and F2a and F2b, act on two points on the same vertical plane. This means that F1a and F1b, and F2a and F2b, are couples. The moment M1 generated by F1a and F1b, and the moment M2 generated by F2a and F2b, are both couple moments. If the jacks 4 extend to the same length, the couple moments M1 and M2 are balanced. This means that hoop beam 1 is balanced as a whole, acting only in tension and without any torque. This is the ideal state.

[0006] The conventional hoop device used for the hydrostatic loading test of shield tunnel prototype segments has the following drawbacks: since it is difficult to adjust the tension of the two jacks 4 on the same hoop beam 1 to the same ideal state, and it is even more difficult to maintain consistency at all times during repeated adjustments, it will cause a situation that does not conform to the ideal moment balance model, thereby introducing uncertainty factors during the test process and easily causing errors in the test results. In addition, in actual application, multiple hoop beams 1 are required to cooperate to complete the test, which adds greater difficulty to the standardized operation test, reducing both test accuracy and test efficiency. If the tension of the two jacks 4 on the same hoop beam 1 differs too much, the hoop beam 1 will be deformed, resulting in uneven stress on the two groups of prestressed tendons 3. In severe cases, it may even cause some prestressed tendons 3 to break, further affecting the accuracy, rigor and safety of the test. In addition, because two jacks 4 are required, the height of the hoop beam 1 is relatively large. If the simulated hydrostatic loading is too large, without increasing the strength by increasing the thickness, the support strength of the middle part of the hoop beam 1 will not meet the pressure requirements, resulting in deformation or damage, making it difficult to meet the test requirements. Summary of the Invention

[0007] The purpose of the present invention is to provide a self-balancing hoop device for water pressure loading test of prototype segments of shield tunnels, in which a hoop beam is equipped with a jack in order to solve the above problems.

[0008] The present invention achieves the above-mentioned purpose through the following technical solutions:

[0009] A self-balancing hoop device for a hydrostatic loading test of a prototype segment of a shield tunnel comprises a hoop beam, prestressed tendons and a jack. In the two opposite and vertical side plates of the hoop beam, the upper and lower parts of one side plate are respectively provided with anchor holes and the middle part is provided with a main wire hole, the upper and lower parts of the other side plate are respectively provided with branch wire holes and the middle part is provided with a wire hole, a jack is installed on the outside of the wire hole of one hoop beam, one end of two groups of prestressed tendons are respectively connected to the two anchor holes, the other ends of the two groups of prestressed tendons respectively pass through the two branch wire holes, then pass through the main wire hole together, and then pass through the wire hole to be connected to the top rod of the jack.

[0010] Preferably, in order to improve the reliability of prestressed tendon wiring, the aperture of the main wire-passing hole is the same as the aperture of the wire-pulling hole, the center point of the main wire-passing hole and the center point of the wire-pulling hole are located in the same horizontal plane, the aperture of the two branch wire-passing holes is smaller than the aperture of the main wire-passing hole, and the vertical distance between the center point of the two branch wire-passing holes and the center point of the wire-pulling hole is smaller than the vertical distance between the center point of the two anchor holes and the center point of the main wire-passing hole.

[0011] Preferably, in order to meet the strength and elasticity requirements, the prestressed tendons are steel strands.

[0012] Preferably, in order to facilitate the installation of the jack, a jack mounting plate is provided on the outer wall of the hoop beam corresponding to the wire hole and the wire hole passes through the jack mounting plate, and the jack is installed on the jack mounting plate.

[0013] Preferably, in order to achieve a better water pressure loading effect and reduce the friction between two vertically adjacent hoop beams to avoid mutual influence, one hoop beam and the two groups of prestressed tendons on the hoop beam and one jack constitute a hoop unit, and the self-balancing hoop device for the water pressure loading test of the shield tunnel prototype segment includes a plurality of hoop units, and a polytetrafluoroethylene plate is provided between two vertically overlapping adjacent hoop units; the polytetrafluoroethylene plate has extremely small friction resistance while meeting the strength requirements, and can avoid mutual influence between two adjacent hoop beams.

[0014] The beneficial effects of the present invention are:

[0015] The present invention reduces the number of jacks on the same hoop beam from the traditional two to one, and connects one end of two sets of prestressed tendons to the mandrel of the same jack. This improves the rationality of the force and loading capacity of the entire hoop device, meeting the loading requirements of ultra-large cross-sections and ultra-high water pressures. The specific advantages are as follows:

[0016] The two sets of prestressed tendons on the same hoop beam have their tension adjusted by the same jack, resulting in consistent tension and balanced resultant force of the two sets of prestressed tendons. There is no moment on the hoop beam, which conforms to the ideal moment balance model. This significantly reduces the error in the test results, facilitates standardized test operation, and improves both test accuracy and test efficiency. Since there is no moment on the hoop beam, and since only one jack is required, the height of the hoop beam can be reduced and its support strength increased, so the hoop beam will not be deformed or damaged, which is conducive to improving the accuracy, rigor and safety of the test, and can adapt to the loading of ultra-high simulated water pressure, making it highly adaptable to engineering applications and usable in a variety of working conditions. The number of jacks can be an odd or even number as needed. Compared with the traditional structure where the number of jacks is always an even number, this improves the convenience of configuring the jacks according to actual needs, and is more flexible and scalable. Since the number of jacks is reduced and damage to the hoop beam is avoided, the test cost is reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is a schematic diagram of the main structure of the hoop beam of a traditional hoop device used for hydraulic loading tests on prototype shield tunnel segments;

[0018] Figure 2 This is a force analysis diagram of the hoop beam of a traditional hoop device used in a hydraulic loading test of a prototype shield tunnel segment, as shown in the main structural diagram during application.

[0019] Figure 3 This is a schematic diagram of the three-dimensional structure of the hoop beam of the self-balancing hoop device for the hydraulic loading test of the prototype segment of the shield tunnel according to the present invention;

[0020] Figure 4 This is a schematic diagram of the main structure of the hoop beam of the self-balancing hoop device for the hydraulic loading test of the prototype segment of the shield tunnel according to the present invention;

[0021] Figure 5 This is a schematic diagram of the three-dimensional structure of the self-balancing hoop device for the hydraulic loading test of the prototype segment of a shield tunnel according to the present invention after the hoop beam and prestressed reinforcement are connected;

[0022] Figure 6 This is a schematic diagram of the three-dimensional structure of the self-balancing hoop device used in the hydraulic loading test of the prototype segment of a shield tunnel according to the present invention;

[0023] Figure 7 This is a force analysis diagram of the hoop beam of the self-balancing hoop device for water pressure loading test of shield tunnel prototype segments described in the present invention when in use, in the main structural diagram. DETAILED DESCRIPTION

[0024] The present invention will be further described below in conjunction with the accompanying drawings:

[0025] like Figure 3-Figure 6 As shown, the self-balancing hoop device for the water pressure loading test of the prototype segment of the shield tunnel described in the present invention includes a hoop beam 5, prestressed tendons 3 and a jack 4. Among the two opposite and vertical side plates of the hoop beam 5, the upper and lower parts of one side plate are respectively provided with anchor holes 9 and the middle part is provided with a total wire hole 10, and the upper and lower parts of the other side plate are respectively provided with branch wire holes 8 and the middle part is provided with a wire hole 6. A jack 4 is installed on the outside of the wire hole 6 of a hoop beam 5, one end of the two groups of prestressed tendons 3 is respectively connected to the two anchor holes 9, and the other ends of the two groups of prestressed tendons 3 respectively pass through the two branch wire holes 8 and then pass through the total wire hole 10 together and then pass through the wire hole 6 to be connected to the top rod of the jack 4.

[0026] like Figure 3-Figure 6 As shown, the present invention also discloses the following multiple groups of more optimized specific structures:

[0027] In order to facilitate improving the reliability of the wiring of the prestressed tendons 3, the aperture of the main wire hole 10 is the same as the aperture of the wire hole 6, the center point of the main wire hole 10 and the center point of the wire hole 6 are located in the same horizontal plane, the aperture of the two branch wire holes 8 is smaller than the aperture of the main wire hole 10, and the vertical distance between the center point of the two branch wire holes 8 and the center point of the wire hole 6 is smaller than the vertical distance between the center point of the two anchor holes 9 and the center point of the main wire hole 10.

[0028] In order to meet the strength and elasticity requirements, the prestressed tendons 3 are steel strands.

[0029] In order to facilitate the installation of the jack 4 , a jack mounting plate 7 is provided on the outer wall of the hoop beam 5 corresponding to the wire hole 6 , and the wire hole 6 passes through the jack mounting plate 7 , and the jack 4 is installed on the jack mounting plate 7 .

[0030] In order to achieve a better water pressure loading effect and reduce the friction between two vertically adjacent hoop beams 5 to avoid mutual influence, a hoop beam 5 and two groups of prestressed tendons 3 and a jack 4 on the hoop beam 5 constitute a hoop unit. The self-balancing hoop device for the water pressure loading test of the shield tunnel prototype segment includes multiple hoop units, and a polytetrafluoroethylene plate (not marked in the figure) is provided between two vertically overlapping adjacent hoop units; the polytetrafluoroethylene plate has extremely small friction resistance while meeting the strength requirements, which can avoid mutual influence between the two adjacent hoop beams 5.

[0031] Combine Figure 3-Figure 6 When used, multiple hoop units are installed on the outer wall of the prototype segment 11. The specific number and arrangement are determined according to actual needs. Figure 6In the figure, three groups of hoop units are evenly arranged in the circumferential direction of the prototype segment 11 , each group includes four hoop units arranged vertically, and the prestressed tendons 3 of all hoop units are staggered and distributed on the outer wall of the prototype segment 11 .

[0032] Each hoop unit is installed as follows: one end of a group of prestressed tendons 3 is fixed through the anchor hole 9 at the upper end, and the other end of the group of prestressed tendons 3 is passed through the corresponding branch wire holes 8 on the other side panel, then looped around the circumferential outer wall of the prototype segment 11, then passed through the main wire hole 10 and the wire hole 6, and finally connected to the top rod of the jack 4. At the same time, one end of another group of prestressed tendons 3 is fixed through the anchor hole 9 at the lower end, and the other end of the group of prestressed tendons 3 is passed through the corresponding branch wire holes 8 on the other side panel, then looped around the circumferential outer wall of the prototype segment 11, then passed through the main wire hole 10 and the wire hole 6 together with the previous group of prestressed tendons 3, and finally connected to the top rod of the jack 4. In this way, the installation of a hoop unit is completed. Then, by adjusting the extension length of the top rod of the jack 4, the pressure of the prestressed tendons 3 on the circumferential outer wall of the prototype segment 11 can be changed to simulate the stress situation of the prototype segment 11 under different loading forces.

[0033] like Figure 7 As shown, the specific force analysis of the hoop beam 5 of each hoop unit of the present invention is as follows: in the vertical direction, F3a is balanced with F'3a; in the horizontal direction, the horizontal resultant force of F3a and F'3a is balanced with F3b; that is, the single hoop beam 5 is balanced and no torque is generated.

[0034] Note: The above-mentioned prestressed tendons 3 and jacks 4 correspond one-to-one with the prestressed tendons 3 and jacks 4 in the background technology content and have the same structure, so the same component names and marking numbers are used. The above-mentioned hoop beam body 5 corresponds to the hoop beam 1 in the background technology content, but the structure has changed, so different component names and marking numbers are used.

[0035] The above embodiments are only preferred embodiments of the present invention and are not limitations on the technical solutions of the present invention. Any technical solution that can be implemented on the basis of the above embodiments without creative work should be deemed to fall within the scope of protection of the patent of the present invention.

Claims

1. A self-balancing hoop device for hydraulic loading testing of prototype shield tunnel segments, comprising a hoop beam, prestressed tendons, and a jack, characterized in that: In the two opposite and vertical side plates of the hoop beam, the upper and lower parts of one side plate are respectively provided with anchor holes and the middle part is provided with a total wire hole, the upper and lower parts of the other side plate are respectively provided with branch wire holes and the middle part is provided with a wire pulling hole, a jack is installed on the outside of the wire pulling hole of one hoop beam, one end of the two groups of prestressed tendons are respectively connected with the two anchor holes, the other ends of the two groups of prestressed tendons respectively pass through the two branch wire holes and then pass through the total wire hole together and then pass through the wire pulling hole and are connected with the top rod of the jack; a hoop beam and the two groups of prestressed tendons on the hoop beam and one jack constitute a hoop unit, and the self-balancing hoop device for water pressure loading test of prototype segments of shield tunnels includes multiple hoop units.

2. The self-balancing hoop device for hydraulic loading test of shield tunnel prototype segments according to claim 1 is characterized in that: The aperture of the total wire passing hole is the same as the aperture of the wire pulling hole, the center point of the total wire passing hole and the center point of the wire pulling hole are located in the same horizontal plane, the aperture of the two branch wire passing holes is smaller than the aperture of the total wire passing hole, and the vertical distance between the center point of the two branch wire passing holes and the center point of the wire pulling hole is smaller than the vertical distance between the center point of the two anchoring holes and the center point of the total wire passing hole.

3. The self-balancing hoop device for hydraulic loading test of shield tunnel prototype segments according to claim 1 is characterized in that: The prestressed tendons are steel strands.

4. The self-balancing hoop device for a shield tunnel prototype segment hydraulic loading test according to claim 1, 2 or 3, characterized in that: A jack mounting plate is provided on the outer wall of the hoop beam body corresponding to the wire pulling hole, and the wire pulling hole passes through the jack mounting plate, and the jack is mounted on the jack mounting plate.

5. The self-balancing hoop device for the hydraulic loading test of a prototype segment of a shield tunnel according to claim 4 is characterized in that: A polytetrafluoroethylene plate is provided between two adjacent vertically overlapping hoop units.

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