Tunnel segment model test box and tunnel segment model test method
By designing a tunnel segment model test chamber, utilizing ball bearings to reduce friction and combining it with a multi-directional loading mechanism, the problems of axial displacement and loading difficulties in existing tunnel segment model tests were solved, enabling the study of transverse stress deformation and damage measurement of tunnel segment structures.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- CHINA RAILWAY SEVENTH GRP CO LTD
- Filing Date
- 2022-06-23
- Publication Date
- 2026-06-09
AI Technical Summary
Existing tunnel segment model testing instruments fail to effectively limit the axial displacement of tunnel segments during loading/unloading, and are difficult to achieve multi-directional coordinated loading and measure the stress, deformation and damage characteristics of segments in soil media environments.
A tunnel segment model test chamber was designed, comprising a chamber body, a loading mechanism, and a tunnel segment fixing mechanism. It utilizes ball bearings to reduce friction and limit axial displacement, and performs multi-directional loading through vertical and horizontal loading mechanisms. Deformation and damage are measured by observation holes.
This study enables a model test of the transverse stress deformation of tunnel segments in a soil environment, which can effectively measure and observe the damage development and failure characteristics of the structure, and improves the accuracy and flexibility of the test.
Smart Images
Figure CN115077965B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of civil engineering, and more particularly to a tunnel segment model test box. Background Technology
[0002] With the large-scale construction and operation of subways, the development and utilization of underground space has been greatly promoted, making urban rail transit a lifeline project for cities. As an indispensable component of urban transportation, subway tunnel segments are prefabricated and assembled structures. Under the influence of close-proximity construction, if the surrounding environment undergoes excessive deformation, the subway tunnel will shift, causing uneven loading and damage to the segments. This will affect the normal operation of the subway, and may even lead to structural failure, resulting in significant economic losses, negative social impacts, and threats to life safety. Therefore, studying the lateral mechanical properties of subway shield tunnel segments is particularly important.
[0003] The study of lateral mechanics problems in subway tunnels can be viewed as plane strain problems. Current testing instruments for tunnel segment models often fail to limit the axial displacement of tunnel segments during loading / unloading, or allow the segments to directly contact the inner wall of the test chamber, generating significant friction. This interferes with the deformation and internal forces of the tunnel segments under lateral stress, hindering the testing process. Furthermore, existing tunnel segment model testing instruments struggle to achieve multi-directional (vertical and horizontal) coordinated loading / unloading control in soil environments, and effectively measure segment stress, deformation, and observe damage and failure characteristics. Summary of the Invention
[0004] This invention provides a tunnel segment model test chamber to solve the aforementioned technical problems.
[0005] A tunnel segment model test chamber includes a chamber body, a loading mechanism, and two tunnel segment fixing mechanisms. The chamber body includes a bottom plate, a front baffle, a rear baffle, and connecting ribs connecting the front and rear baffles. The front and rear baffles are respectively fixed to the bottom plate and arranged parallel to each other in the front-rear direction. The connecting ribs are respectively fixed to the top sides of the front and rear baffles. The loading mechanism includes a vertical loading mechanism at the top of the chamber body and / or a horizontal loading mechanism on both sides of the chamber body. The tunnel segment fixing mechanism includes an annular sleeve plate for fitting the tunnel segment, an annular support plate fixed to one end face of the annular sleeve plate, and an annular sealing plate. The annular support plate is provided with a ring of multiple support units distributed in a circle. Each support unit includes a spring hole on the outer surface of the annular support plate, a compression spring in the spring hole, and a ball bearing that presses against the outer end of the compression spring. The diameter of the ball bearing is smaller than the diameter of the spring hole. The annular sealing plate is provided with a spherical annular through hole for the ball bearing to pass through. The annular sealing plate is fixed to the annular support plate by multiple screws distributed in the circumferential direction.
[0006] Preferably, the loading mechanism includes a vertical loading mechanism and a horizontal loading mechanism. The vertical loading mechanism includes at least one vertical hydraulic push rod, and a horizontal pressure plate is fixed to the push rod end of each vertical hydraulic push rod. The horizontal loading mechanism includes at least one horizontal hydraulic push rod, and a vertical pressure plate is fixed to the push rod end of each horizontal hydraulic push rod.
[0007] Preferably, an observation hole is provided in the middle of the front baffle and / or rear baffle, and the diameter of the observation hole is smaller than the diameter of the tube segment.
[0008] Preferably, a horizontal plate is movably clamped at the top between the front baffle and the rear baffle, and vertical plates are movably clamped on both sides between the front baffle and the rear baffle.
[0009] Preferably, when the vertical plate is located on both sides of the box body, there is a gap between the vertical plate and the horizontal plate in the horizontal direction, and the two ends of the horizontal plate have flexible retaining plates.
[0010] The method for conducting tunnel segment model tests using the above-mentioned tunnel segment model test box includes the following steps: Step 1: First, fill the box with soil, compact it in layers, and the soil in the box reaches the set height; insert both ends of the tunnel segment into the tunnel segment fixing mechanism;
[0011] Step 2: Place the tunnel segments and tunnel segment fixing mechanism together on the backfill and insert them between the front baffle and the rear baffle. Continue to seal the soil and compact it in layers until the preset test height is reached.
[0012] Step 3: Start the loading mechanism to conduct vertical and / or horizontal loading / unloading tests on the sealed soil according to the test requirements. During the test, the stress on the pipe segment structure is measured by attaching strain gauges, and the deformation of the pipe segment structure is measured and the damage development and failure characteristics of the structure are observed by setting sensors through observation holes.
[0013] In the tunnel segment model test box of the present invention, soil is first filled into the box, then the two ends of the tunnel segment structure are inserted into the tunnel segment fixing mechanism, and then placed on the soil and locked between the front baffle and the rear baffle. Then, the soil is sealed again until the preset soil filling height is reached. Then, the loading mechanism is activated to conduct vertical and / or lateral loading / unloading tests on the sealed soil as needed. Since the tunnel segment fixing mechanism contains ball bearings, the friction is very small. The loading / unloading test in the soil medium environment can realize the lateral movement of the tunnel segment model. In addition, since the ball bearings are pressed against the front baffle and the rear baffle, the axial displacement of the tunnel segment can be greatly restricted, which can better carry out the lateral stress deformation model test research of the tunnel segment structure.
[0014] Furthermore, both the vertical and horizontal loading mechanisms are equipped with multiple hydraulic push rods, allowing for localized loading as needed and providing flexibility in use.
[0015] Furthermore, an observation hole is provided in the middle of the front baffle and / or rear baffle. The diameter of the observation hole is smaller than the diameter of the tunnel segment, which facilitates the measurement of the stress deformation of the tunnel segment structure and the observation of the damage development process and failure characteristics of the tunnel segment structure.
[0016] Furthermore, a horizontal plate is movably clamped at the top between the front baffle and the rear baffle, and vertical plates are movably clamped on both sides between the front baffle and the rear baffle to prevent soil overflow. The horizontal pressure plate of the loading mechanism presses on the horizontal plate, and the vertical pressure plate of the loading mechanism presses on the vertical plate, which facilitates the loading mechanism to perform loading.
[0017] Furthermore, when the vertical plates are located on both sides of the box body, there is a gap between the vertical plates and the horizontal plates in the horizontal direction, so that there is loading space in both the vertical and horizontal directions, and loading / unloading can be carried out simultaneously as needed. The two ends of the horizontal plates have flexible soil retaining plates to prevent soil from overflowing from above. Attached Figure Description
[0018] Figure 1 This is a schematic diagram of the tunnel segment model test box in this invention.
[0019] Figure 2 This is a side view of the tunnel segment model test chamber.
[0020] Figure 3 yes Figure 2 Enlarged structural diagram at point A in the middle. Detailed Implementation
[0021] Example 1
[0022] An embodiment of a tunnel segment model test chamber, such as... Figure 1-3As shown, it includes a box body, a loading mechanism, and two tunnel segment fixing mechanisms 9 and 9'. The box body includes a bottom plate 1, a front baffle 4, a rear baffle 4', a horizontal plate 10, two vertical plates 3 and 3', and a connecting rib 5 connecting the front baffle and the rear baffle. The front baffle and the rear baffle are respectively fixed on the bottom plate and are arranged parallel to each other in the front-rear direction. The horizontal plate is movably clamped at the top between the front baffle and the rear baffle, and the vertical plates are movably clamped on both sides between the front baffle and the rear baffle. The connecting ribs 5 are fixed to the top sides of the front baffle and the rear baffle respectively. The loading mechanism includes a vertical loading mechanism on the top of the box and a horizontal loading mechanism on both sides of the box. The vertical loading mechanism includes three vertical hydraulic push rods, and a horizontal pressure plate 6 is fixed to the push rod end of each vertical hydraulic push rod. The horizontal loading mechanism includes three horizontal hydraulic push rods, and a vertical pressure plate 2, 2' is fixed to the push rod end of each horizontal hydraulic push rod. The loading mechanism is existing technology and can be fixed by a reaction frame, etc., which will not be elaborated here. For ease of reading, only the horizontal pressure plate and the vertical pressure plate are shown in the figure. The tunnel segment fixing mechanism includes an annular sleeve plate 11 for mounting the tunnel segments, an annular support plate 12 fixed to one end face of the annular sleeve plate, and an annular sealing plate 13. The annular support plate has a ring of support units distributed in a circular pattern. Each support unit includes a spring hole 16 on the outer surface of the annular support plate, a compression spring 17 in the spring hole, and a ball bearing 15 that presses against the outer end of the compression spring. The diameter of the ball bearing is smaller than the diameter of the spring hole. The annular sealing plate has a spherical annular through hole for the ball bearing to pass through. The annular sealing plate is fixed to the annular support plate by a plurality of circumferentially distributed screws 14. An observation hole 7 is also provided in the middle of the front baffle and / or rear baffle. The diameter of the observation hole is smaller than the diameter of the tunnel segment, facilitating the measurement of the stress deformation of the tunnel segment structure and the observation of the damage development process and failure characteristics of the tunnel segment structure. In this embodiment, when the vertical plate is located on both sides of the box body, there is a gap between the vertical plate and the horizontal plate in the horizontal direction. The two ends of the horizontal plate have flexible retaining plates, which can be rubber plates (not shown in the figure). In this way, there is loading space in both the vertical and horizontal directions, and loading / unloading can be carried out simultaneously as needed. The two ends of the horizontal plate have flexible retaining plates to prevent soil from overflowing from above.
[0023] The tunnel segment model test chamber of this invention is used by first filling the chamber with soil, then inserting both ends of the tunnel segment structure into the tunnel segment fixing mechanism, placing it on the soil and locking it between the front and rear baffles, and then continuing to seal the soil until the preset filling height is reached. The loading mechanism is then activated to conduct vertical and / or lateral loading / unloading tests as needed. Because the tunnel segment fixing mechanism contains ball bearings, the friction is very low, and the loading / unloading test in the soil medium environment can achieve lateral movement of the tunnel segment model. Furthermore, because the ball bearings press against the front and rear baffles, the axial displacement of the tunnel segment can be greatly restricted, enabling better research on the lateral stress and deformation model test of the tunnel segment structure. Both the vertical and horizontal loading mechanisms are equipped with multiple hydraulic push rods, allowing for localized loading as needed, providing flexibility in use. A horizontal plate is movably clamped at the top between the front baffle and the rear baffle, and vertical plates are movably clamped on both sides between the front baffle and the rear baffle to prevent soil from overflowing. The horizontal pressure plate of the loading mechanism presses on the horizontal plate, and the vertical pressure plate of the loading mechanism presses on the vertical plate, which facilitates the loading mechanism to perform loading.
[0024] In other embodiments, unlike the embodiments described above, the loading mechanism includes a vertical loading mechanism located at the top of the box or a horizontal loading mechanism located on both sides of the box. The vertical loading mechanism includes one or more vertical hydraulic push rods, and the horizontal loading mechanism includes one or more transverse hydraulic push rods.
[0025] Example 2
[0026] The method for conducting tunnel segment model tests using the aforementioned tunnel segment model test box, such as... Figure 1-3 As shown, the process includes the following steps: Step 1: First, fill the box with soil, compact it in layers, and the soil in the box reaches the set height; the two ends of the tunnel segment 8 are inserted into the tunnel segment fixing mechanism. The tunnel segment 8 is a prefabricated multi-ring tunnel segment.
[0027] Step 2: Place the tunnel segments and tunnel segment fixing mechanism together on the backfill and insert them between the front baffle and the rear baffle. Continue to seal the soil and compact it in layers until the preset test height is reached.
[0028] Step 3: Start the loading mechanism to conduct vertical and / or horizontal loading / unloading tests on the sealed soil according to the test requirements. During the test, the stress on the pipe segment structure is measured by attaching strain gauges, and the deformation of the pipe segment structure is measured and the damage development and failure characteristics of the structure are observed by setting sensors through observation holes.
Claims
1. A tunnel segment model test chamber, characterized in that: The system includes a housing, a loading mechanism, and two tunnel segment fixing mechanisms. The housing includes a base plate, a front baffle, a rear baffle, and connecting ribs connecting the front and rear baffles. The front and rear baffles are fixed to the base plate and arranged parallel to each other in the front-rear direction. The connecting ribs are fixed to the top sides of the front and rear baffles, respectively. The loading mechanism includes a vertical loading mechanism at the top of the housing and / or a horizontal loading mechanism on both sides of the housing. The tunnel segment fixing mechanism includes an annular sleeve for mounting the tunnel segments, an annular support plate fixed to one end face of the annular sleeve, and an annular sealing plate. The annular support plate is provided with a ring of multiple support units distributed in a circle. Each support unit includes a spring hole on the outer surface of the annular support plate, a compression spring in the spring hole, and a ball bearing that presses against the outer end of the compression spring. The diameter of the ball bearing is smaller than the diameter of the spring hole. The annular sealing plate is provided with a spherical annular through hole for the ball bearing to pass through. The annular sealing plate is fixed to the annular support plate by multiple screws distributed in the circumferential direction.
2. The tunnel segment model test chamber according to claim 1, characterized in that: The loading mechanism includes a vertical loading mechanism and a horizontal loading mechanism. The vertical loading mechanism includes at least one vertical hydraulic push rod, and a horizontal pressure plate is fixed to the push rod end of each vertical hydraulic push rod. The horizontal loading mechanism includes at least one horizontal hydraulic push rod, and a vertical pressure plate is fixed to the push rod end of each horizontal hydraulic push rod.
3. The tunnel segment model test chamber according to claim 2, characterized in that: An observation hole is also provided in the middle of the front baffle and / or rear baffle, and the diameter of the observation hole is smaller than the diameter of the tube segment.
4. The tunnel segment model test chamber according to claim 3, characterized in that: A horizontal plate is movably clamped at the top between the front baffle and the rear baffle, and vertical plates are movably clamped on both sides between the front baffle and the rear baffle.
5. A tunnel segment model test chamber according to claim 4, characterized in that: When the vertical plate is located on both sides of the box body, there is a gap between the vertical plate and the horizontal plate in the horizontal direction, and the two ends of the horizontal plate have flexible retaining plates.
6. A method for conducting tunnel segment model tests using the tunnel segment model test chamber of claim 5, characterized by the following steps: Step 1: First, fill the box with soil, compact it in layers, and wait for the soil in the box to reach the set height. Both ends of the tunnel segment are inserted into the tunnel segment fixing mechanism; Step 2: Place the tunnel segments and tunnel segment fixing mechanism together on the backfill and insert them between the front baffle and the rear baffle. Continue to seal the soil and compact it in layers until the preset test height is reached. Step 3: Start the loading mechanism to conduct vertical and / or horizontal loading / unloading tests on the sealed soil according to the test requirements. During the test, the stress on the pipe segment structure is measured by attaching strain gauges, and the deformation of the pipe segment structure is measured and the damage development and failure characteristics of the structure are observed by setting sensors through observation holes.