A self-resetting energy dissipation device for shock absorption of shield tunnels

Abstract

The present invention belongs to the field of shock absorption for shield tunnels, and specifically discloses a self-resetting energy dissipation device for shock absorption of shield tunnels, which includes a steel core outer ring, a waterproof gasket, a rubber gasket, and a shape memory alloy ring. Among them: an inclination angle is provided on the inner side of the steel core outer ring, and a groove is opened on the outer side; the waterproof gasket is fixed in the groove on the outer side of the steel core outer ring, and the rubber gasket is attached to the waterproof gasket and the outer side of the steel core outer ring; the shape memory alloy ring is installed between the two steel core outer rings, and its surface is attached to the inclination angle on the inner side of the steel core outer ring; when an external force is applied, the distance between the two steel core outer rings is compressed, and the shape memory alloy ring deforms due to the extrusion of the steel core outer ring, expands outward and generates a restoring force, thereby dissipating energy and promoting the reset of the device structure. The device of the present invention has a good buffering effect, can dissipate energy, and can also provide a restoring force, playing a role of self-resetting after an earthquake and reducing the tunnel maintenance and replacement costs.

Description

Technical Field

[0001] The invention belongs to the field of shield tunnel shock absorption, and more specifically, relates to a self-resetting energy dissipation device for shield tunnel shock absorption. Background Art

[0002] At present, most urban underground rail transit adopts the underground structure form of shield tunnels. The seismic performance of shield tunnels directly affects the safety of urban traffic. A shield tunnel is composed of many segments and bolts connected to each other, and the segment joint part is its weak link. The performance of the joint determines the overall stiffness and deformation ability of the shield tunnel, and also plays a key role in the waterproofing of the structure.

[0003] The main manifestations of shield tunnel earthquake damage are segment cracking, dislocation, water leakage, and joint damage, etc. The stiffness of the connecting bolts is relatively low, and stress concentration is likely to occur under earthquake action and cause serious deformation. Therefore, the earthquake damage at the joint part is very prominent. Large deformations at the joint part of the shield tunnel during an earthquake will cause seismic damages such as bolt yield, fracture, and joint water leakage, resulting in tunnel dislocation and water leakage, and causing the shield tunnel to lose its normal use function without damage to the main body of the segment structure.

[0004] At present, there are very few devices studied and applied in tunnel shock absorption, and even fewer shock absorption structures that can play an energy dissipation and self-resetting role in shield tunnels. Most of the existing devices only play a buffering role, with a small energy dissipation effect, and do not have the ability to quickly restore the structural function after an earthquake. For example, Patent CN 110107577 A provides a shock absorption and energy dissipation device for shield tunnel bolt joints. This device has the following disadvantages: 1. This design uses rubber gaskets and ordinary springs as shock absorption elements, which only play a buffering role during an earthquake and have a very small energy dissipation effect; 2. When an earthquake occurs, the rubber gasket is compressed and deformed limitedly, which reduces the buffering effect to a certain extent. The deformation of the spring depends on the total deformation of the rubber gasket to achieve the corresponding effect, and the effect is limited; 3. This device does not have a self-resetting function after an earthquake. Therefore, the development and design of a shield tunnel shock absorption device based on self-resetting energy dissipation is of great significance. Summary of the Invention

[0005] Aiming at the above defects or improvement requirements of the prior art, the invention provides a self-resetting energy dissipation device for shield tunnel shock absorption. The purpose is to install the device composed of a shape memory alloy ring, a steel core, a rubber gasket, and a waterproof gasket at both ends of the connecting bolts of the tunnel segments. When displacement occurs between the segments during an earthquake, the device is squeezed between the bolt head / nut and the segment, playing a buffering role, dissipating part of the earthquake energy at the same time, and providing a restoring force after the earthquake to reduce the residual opening amount, thereby reducing the risk of bolt fracture and joint water leakage.

[0006] To achieve the above object, the present invention proposes a self - resetting energy - dissipating device for shield tunnel shock absorption, which includes a steel - core outer ring, a waterproof gasket, a rubber gasket, and a shape - memory alloy ring, wherein:

[0007] An inclination angle is provided on the inner side of the steel - core outer ring, and a groove is provided on the outer side; the waterproof gasket is fixed in the groove on the outer side of the steel - core outer ring, and the rubber gasket is attached to the waterproof gasket and the outer side of the steel - core outer ring; the shape - memory alloy ring is installed between two steel - core outer rings, and its surface fits with the inclination angle on the inner side of the steel - core outer ring; when an external force is applied, the distance between the two steel - core outer rings is compressed, and the shape - memory alloy ring deforms due to the extrusion of the steel - core outer ring, expands outward and generates a restoring force, thereby dissipating energy and promoting the reset of the device structure.

[0008] As a further preference, the device further includes n steel - core inner rings, which are all arranged between two steel - core outer rings, and inclination angles are provided on both sides of each steel - core inner ring; the number of shape - memory alloy rings is n + 1, n≥1, wherein, for the shape - memory alloy rings at both ends, one side surface fits with the inclination angle on the inner side of the steel - core outer ring, and the other side surface fits with the inclination angle of the steel - core inner ring; for the shape - memory alloy rings in the middle, both side surfaces fit with the inclination angles of the steel - core inner rings.

[0009] As a further preference, the contact surface between the waterproof gasket and the steel - core outer ring, and the contact surface between the waterproof gasket and the rubber gasket are bonded with waterproof glue, and the contact surface between the rubber gasket and the steel - core outer ring is connected by vulcanization technology treatment or bonded with waterproof glue.

[0010] As a further preference, the inclination angle on the inner side of the steel - core outer ring and the inclination angles on both sides of the steel - core inner ring are 15° - 25°.

[0011] As a further preference, the contact surfaces of the shape - memory alloy ring with the steel - core outer ring and the steel - core inner ring are treated with grease, lubricating oil or plating coating.

[0012] As a further preference, the height of the inclined - angle part of the steel - core outer ring is greater than half of the height of the shape - memory alloy ring, and the height of the steel - core inner ring is greater than the height of the shape - memory alloy ring.

[0013] As a further preference, the maximum diameter of the upper end of the steel - core outer ring is greater than the maximum diameter of the shape - memory alloy ring after being extruded.

[0014] As a further preference, when the shape - memory alloy ring is extruded to reach the maximum diameter, the elongation rate relative to the initial minimum diameter of the shape - memory alloy ring is less than 7%.

[0015] As a further preference, the outer steel core ring and the inner steel core ring are made of 38CrMoAl alloy material, the shape memory alloy ring is made of nickel-titanium alloy material, and the waterproof gasket is made of water-swellable rubber material.

[0016] As a further preference, chamfers are made at the edges of the lower end of the outer steel core ring and the inclined surface of the inner inclined angle ring.

[0017] Generally speaking, compared with the prior art, the above technical solutions conceived by the present invention mainly have the following technical advantages:

[0018] 1. The device of the present invention is installed at both ends of the connecting bolts of the tunnel segment. When displacement occurs between the segments during an earthquake, the device is squeezed between the bolt head / nut and the segment, playing a buffering role, dissipating part of the seismic energy at the same time, and providing a restoring force after the earthquake to reduce the residual opening amount, thereby reducing the risk of bolt fracture and joint leakage. It can be applied to various working conditions of the shield tunnel bolt joint and has a self-resetting function.

[0019] 2. The device of the present invention uses a ring spring composed of an SMA ring and a steel core. Compared with an ordinary steel spring, it has the advantages of high stiffness, high bearing capacity and energy dissipation; and the SMA rings can be stacked and connected in series according to needs, with strong flexibility.

[0020] 3. The present invention sets the inner inclination angle of the outer steel core ring and the two-side inclination angles of the inner steel core ring to be 15°-25°, so that there is a certain angle at the contact part with the SMA ring. If the angle is too small, the contact surface friction force will be too large, resulting in incomplete recovery, and when the angle is too large, the compressive stress on the contact surface of the SMA ring will be too large, resulting in plastic deformation and affecting the performance.

[0021] 4. The contact surfaces of the SMA ring of the present invention with the outer steel core ring and the inner steel core ring are treated with grease, lubricating oil or coating, which can adjust the contact surface friction coefficient and improve the performance of the SMA ring.

[0022] 5. The present invention sets the height of the inclined part of the outer steel core ring to be greater than half of the height of the shape memory alloy ring, so that when the device is completely compressed, the SMA ring can fully expand, and the upper and lower surfaces will not contact the protruding part of the upper part of the outer steel core ring, avoiding damage. At the same time, the lower surfaces of the two outer steel core rings can contact to form self-locking, avoiding excessive expansion of the SMA ring and causing damage, and enabling the device to obtain greater bearing capacity.

[0023] 6. The maximum diameter of the upper part of the outer steel core ring is slightly larger than the maximum diameter of the SMA ring when the device is self-locked, which can avoid the SMA ring from contacting the tunnel segment or other structures when it expands to the maximum.

[0024] 7. When the device is self-locking, the elongation rate of the minimum inner diameter of the SMA ring is less than 7%, because if the elongation rate of the SMA material is too large, it may exceed the range of superelasticity of the component and cause residual deformation, resulting in the device being unable to fully reset.

[0025] 8. In the present invention, a waterproof gasket is installed in the groove of the outer ring of the steel core, and a rubber gasket is provided on the outer layer. The rubber gasket can play a buffering role and reduce the damage caused by possible stress concentration on the contact surfaces between the bolt head and the segment and the outer ring of the steel core; the waterproof gasket is made of a water-swellable material. When water seeps into the position of the bolt joint, the waterproof gasket swells when it encounters water, and can block the gap, thereby playing a waterproof role. Especially under the extrusion and restraint of the outer ring of the steel core and the rubber gasket, the deformation of the waterproof gasket can be restricted inside, greatly improving the waterproof performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 is a schematic structural diagram of the self-resetting energy dissipation device according to an embodiment of the present invention (single SMA ring);

[0027] Figure 2 is a schematic structural diagram of the self-resetting energy dissipation device according to an embodiment of the present invention (multiple SMA rings);

[0028] Figure 3 is a schematic diagram of the action process of the self-resetting energy dissipation device according to an embodiment of the present invention (single SMA ring);

[0029] Figure 4 is a schematic diagram of the action process of the self-resetting energy dissipation device according to an embodiment of the present invention (multiple SMA rings);

[0030] Figure 5 in which (a) and (b) are respectively the sectional view and top view of the outer ring of the steel core according to an embodiment of the present invention;

[0031] Figure 6 in which (a) and (b) are respectively the sectional view and top view of the rubber gasket according to an embodiment of the present invention;

[0032] Figure 7 in which (a) and (b) are respectively the sectional view and top view of the waterproof gasket according to an embodiment of the present invention;

[0033] Figure 8 in which (a) and (b) are respectively the sectional view and top view of the SMA ring according to an embodiment of the present invention;

[0034] Figure 9 is a schematic structural diagram of the SMA ring according to an embodiment of the present invention;

[0035] Figure 10 in which (a) and (b) are respectively the sectional view and top view of the inner ring of the steel core according to an embodiment of the present invention;

[0036] Figure 11 Structural schematic diagram of the steel core inner ring in the embodiment of the present invention;

[0037] Figure 12 Installation schematic diagram of the self-resetting energy dissipation device in the embodiment of the present invention on the inclined bolt joint;

[0038] Figure 13 Installation schematic diagram of the self-resetting energy dissipation device in the embodiment of the present invention on the bent bolt joint.

[0039] In all the drawings, the same reference numerals are used to represent the same elements or structures, where: 1 - bolt, 2 - bolt head, 3 - tunnel segment, 4 - segment manhole, 5 - rubber washer, 6 - waterproof washer, 7 - steel core outer ring, 8 - shape memory alloy ring, 9 - steel core inner ring, 10 - inclined bolt, 11 - bent bolt, 12 - nut. Specific embodiments

[0040] In order to make the objectives, technical solutions and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0041] A self-resetting energy dissipation device for shock absorption of shield tunnels provided by an embodiment of the present invention, as Figure 1 shown, includes a steel core outer ring 7, a waterproof washer 6, a rubber washer 5, and a shape memory alloy ring (SMA ring) 8, where:

[0042] The steel core outer ring 7 is as Figure 5 shown, with an inclination angle on its inner side and a groove on its outer side; the waterproof washer 6 is as Figure 7 shown, fixed in the groove on the outer side of the steel core outer ring 7 to prevent water from entering the interior of the device; the rubber washer 5 is as Figure 6 shown, attached to the outer sides of the waterproof washer 6 and the steel core outer ring 7 to play a buffering role; the shape memory alloy ring 8 is as Figure 8 and Figure 9 shown, installed between the two steel core outer rings 7, and its surface fits the inclination angle on the inner side of the steel core outer ring 7.

[0043] When multiple shape memory alloy rings 8 are connected in series (the number of shape memory alloy rings is n + 1, n ≥ 1), then n steel core inner rings 9 are also required, all of which are arranged between the two steel core outer rings 7, and both sides of each steel core inner ring 9 are provided with inclination angles, as Figure 10 and Figure 11As shown in the figure; among them, one side surface of the shape memory alloy rings 8 located at both ends is inclined and fitted to the inner side of the outer steel core ring 7, and the other side surface is inclined and fitted to the inner steel core ring 9; both side surfaces of the shape memory alloy rings 8 located in the middle are inclined and fitted to the inner steel core ring 9, as Figure 2 shown.

[0044] During use, the device is installed on the end heads of the shield tunnel segment connection bolts 1 (including inclined bolts, bent bolts, straight bolts, etc.), and the installation position is between the bolt head 2 or the nut 12 and the tunnel segment 3. During installation, a certain prestress will be applied, and the device will be compressed to a certain extent.

[0045] When an earthquake occurs or the external conditions change, causing the bolt to be in tension, a pressure is generated between the bolt head and the closely attached outer steel core ring, forcing the outer steel core ring to move inward. The device will be compressed, and there is an inclination angle between the contact surfaces of the outer steel core ring and the SMA ring, causing the SMA ring to expand outward during the compression process. Due to the superelasticity of the SMA material, it deforms under the action of an external tensile force and can completely return to its original state after the external force is unloaded, and energy will be dissipated during the process. At the same time, when the SMA ring expands outward, a pressure and frictional force are generated between the contact surfaces of the SMA ring and the outer steel core ring or the inner steel core ring, which will give the steel core an outward elastic force to generate a restoring force, and the friction between the contact surfaces will also dissipate energy. During the reciprocating loading and unloading process of the device, a large amount of energy will be dissipated by the device, and it has a restoring force to help the device structure reset and reduce the damage caused by the earthquake.

[0046] When the device is compressed and comes into play, as Figure 3 and Figure 4 shown, it can be seen that the SMA ring expands outward, and the device generates an elastic force, which can buffer the impact load during an earthquake. At the same time, the expansion of the SMA ring and the friction of the contact surface will both dissipate energy to reduce damage; after the earthquake, the restoring force of the device helps the tunnel segment to reset, reduces the opening amount, and lowers the repair cost.

[0047] Furthermore, the inner hole diameters of the rubber washer and the waterproof washer should be smaller than the inner hole diameter of the outer steel core ring, but not less than the bolt diameter, so as to reduce the initial gap between the washer and the bolt during installation; the waterproof washer is made of water-swellable rubber material. Under the action of extrusion restraint, when the waterproof washer encounters water, it can only expand into the gap inside the bolt, thereby sealing the gap and preventing water seepage; the contact surfaces between the waterproof washer and the outer steel core ring, and between the waterproof washer and the rubber washer are bonded with waterproof glue. The contact surface between the rubber washer and the outer steel core ring is connected by vulcanization technology treatment or bonded with waterproof glue.

[0048] Furthermore, there is a certain angle at the contact part between each outer steel core ring and the SMA ring. This angle ranges from 15° to 25°. If the angle is too small, the frictional force on the contact surface will be too large, resulting in incomplete recovery. When the angle is too large, the compressive stress on the contact surface of the SMA ring will be too large, causing plastic deformation and affecting the performance. The contact surface can be treated with grease, lubricating oil, coating, etc. to adjust the friction coefficient of the contact surface and improve the performance of the SMA ring. The inclination angle of the inner steel core ring and the contact surface treatment are the same as those of the outer steel core ring.

[0049] Furthermore, the height of the inclined part of the outer steel core ring is slightly greater than half of the height of the shape memory alloy ring. In this way, when the device is fully compressed, the SMA ring can expand fully, and the upper and lower surfaces will not contact the protruding part at the upper part of the outer steel core ring, avoiding damage. At the same time, the lower surfaces of the two outer steel core rings can contact to form self-locking, preventing the SMA ring from over-expanding and causing damage, and enabling the device to obtain greater bearing capacity. A rubber gasket can also be installed on the lower surface of the outer steel core ring to avoid damage caused by stress mutation during self-locking. Similarly, the height of the inner steel core ring should be slightly greater than the height of the SMA ring.

[0050] Furthermore, the maximum diameter at the upper end of the outer steel core ring is slightly greater than the maximum diameter of the SMA ring when the device is self-locked, so as to prevent the SMA ring from possibly contacting the tunnel segment or other structures when it expands to the maximum.

[0051] Furthermore, when designing the dimensions of the device, there should be sufficient parts of the outer steel core ring and the inner steel core ring initially embedded in the SMA ring, which can improve the installation reliability and the stability of the device.

[0052] Furthermore, the edges and corners of the lower end of the outer steel core ring and the inclined outer ring surface on the inner side are chamfered, and the edges and corners are rounded to make the sliding with the SMA ring smoother and avoid cutting or embedding between the two.

[0053] Furthermore, when the shape memory alloy ring is compressed to the maximum diameter, that is, when the device is self-locked, the elongation rate relative to the initial minimum diameter of the shape memory alloy ring is less than 7%.

[0054] Furthermore, the outer steel core ring and the inner steel core ring are made of high-strength steel 38CrMoAl alloy material or other high-strength stainless steel materials, and the SMA ring is made of nickel-titanium alloy material, with strong corrosion resistance and can adapt to complex environmental working conditions.

[0055] Specifically, the stiffness, strength, recovery force magnitude, and energy dissipation capacity of the device can be adjusted by adjusting the inclination angle between the SMA ring and the steel core, the friction coefficient of the contact surface, and the thickness of the SMA ring. The performance and installation space can also be adjusted by changing the maximum diameter and height of the steel core and the SMA ring, and the performance can also be improved by connecting multiple SMA rings in series.

[0056] The device described in the present invention can be applicable to various bolt forms such as inclined bolts, bent bolts, straight bolts, double straight bolts, etc. for segment joints of shield tunnels; for example, Figure 12 as shown, it is for installing the device on the inclined bolt 10 at the segment manhole 4; as Figure 13 shown, it is for installing the device on the bent bolt 11 at the segment manhole 4. The assembly and installation process of this device is specifically as follows:

[0057] (1) Install the waterproof gasket in the groove of the outer ring of the steel core and bond it, then bond the rubber gasket on the upper surface of the outer ring of the steel core to form a complete outer ring of the steel core. This part can be processed in batches in advance;

[0058] (2) Lubricate the contacting surfaces of the outer ring of the steel core, the inner ring of the steel core and the SMA ring, apply lubricating oil or plating. After the treatment, insert the bolts in the order of "completed assembled outer ring of the steel core - SMA ring - inner ring of the steel core - SMA ring -..... - completed assembled outer ring of the steel core" and embed them into the rings with each other; this step can be pre-connected and encapsulated into a complete device, and then the whole is inserted into the bolt to improve the assembly accuracy and stability of the device;

[0059] (3) Apply prestress according to the construction requirements. The prestress can be estimated by observing the compression amount of the device or the number of thread rotations, and then the installation is completed.

[0060] It is easy for those skilled in the art to understand that the above is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A self-resetting energy dissipation device for shock absorption of shield tunnels, characterized in that It includes a steel core outer ring, a waterproof gasket, a rubber gasket, a shape memory alloy ring and n steel core inner rings, where: An inclination angle is provided on the inner side of the steel core outer ring, and a groove is provided on the outer side; the waterproof gasket is fixed in the groove on the outer side of the steel core outer ring, and the rubber gasket is attached to the waterproof gasket and the outer side of the steel core outer ring; the shape memory alloy ring is installed between the two steel core outer rings, and its surface fits the inclination angle on the inner side of the steel core outer ring; when an external force is applied, the distance between the two steel core outer rings is compressed, and the shape memory alloy ring deforms due to the extrusion of the steel core outer ring, expands outward and generates a restoring force, thereby dissipating energy and prompting the device structure to reset; The n steel core inner rings are all arranged between the two steel core outer rings, and inclination angles are provided on both sides of each steel core inner ring; the number of the shape memory alloy rings is n + 1, n≥1, where the surface of the shape memory alloy rings at both ends on one side fits the inclination angle on the inner side of the steel core outer ring, and the surface on the other side fits the inclination angle of the steel core inner ring; the surfaces on both sides of the shape memory alloy rings in the middle fit the inclination angles of the steel core inner rings; The inclination angle on the inner side of the steel core outer ring and the inclination angles on both sides of the steel core inner ring are 15° - 25°; the height of the inclined angle part of the steel core outer ring is greater than half of the height of the shape memory alloy ring, and the height of the steel core inner ring is greater than the height of the shape memory alloy ring.

2. The self-resetting energy dissipation device for shield tunnel shock absorption according to claim 1, characterized in that, The contact surface between the waterproof gasket and the steel core outer ring, and the contact surface between the waterproof gasket and the rubber gasket are bonded with waterproof glue, and the contact surface between the rubber gasket and the steel core outer ring is connected by vulcanization technology treatment or bonded with waterproof glue.

3. The self-resetting energy dissipation device for shield tunnel shock absorption according to claim 1, characterized in that The contact surfaces of the shape memory alloy ring with the steel core outer ring and the steel core inner ring are treated with grease, lubricating oil or plating coating.

4. The self-resetting energy dissipation device for shield tunnel shock absorption according to claim 1, characterized in that, The maximum diameter of the upper end of the steel core outer ring is greater than the maximum diameter of the shape memory alloy ring after being extruded.

5. The self-resetting energy dissipation device for shield tunnel shock absorption according to claim 1, characterized in that, When the shape memory alloy ring is extruded to reach the maximum diameter, the elongation rate relative to the initial minimum diameter of the shape memory alloy ring is less than 7%.

6. The self-resetting energy dissipation device for shield tunnel shock absorption according to claim 1, wherein The steel core outer ring and the steel core inner ring are made of 38CrMoAl alloy material, the shape memory alloy ring is made of nickel-titanium alloy material, and the waterproof gasket is made of water-swellable rubber material.

7. The self-resetting energy dissipation device for shield tunnel shock absorption according to any one of claims 1-6, characterized in that, The edges and corners of the lower end of the steel core outer ring and the outer ring surface of the inner side inclined angle are chamfered.

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