A prototype loading test device and test method for shaft-type shield segments

Abstract

The present invention proposes a prototype loading test device and test method for shaft-type shield segments, which relate to the technical field of shield tunnel engineering, wherein the test device includes a support body and a reaction frame body, and the reaction frame body is provided with a radial loading assembly, a hoop loading assembly and a hoisting loading assembly; the test ring segments are placed vertically, and equivalent bending moments are applied in stages by the radial loading assembly, equivalent axial forces are applied in stages by the hoop loading assembly, and lifting forces are applied in stages by the hoisting loading assembly to achieve self-weight balance. The present invention is a standing segment prototype loading test, which simulates the actual stress state of the segment more realistically than the flat-lying test of the prior art; in addition, the present invention achieves self-weight balance through the hoisting loading assembly, which can accurately simulate the self-weight reaction force of the segment provided by the stratum in actual working conditions, solves the problem of self-weight reaction concentration in the standing segment prototype loading test, and more realistically simulates the actual stress state of the segment.

Description

Technical Field

[0001] The present invention relates to the technical field of shield tunnel engineering, and in particular to a shaft-type shield segment prototype loading test device and a test method. Background Art

[0002] In recent years, with the continuous advancement of my country's overall urban planning, influenced by factors such as environmental conditions along the route and ground transportation, the use of shield tunnel construction has gradually become a trend when transportation routes enter urban areas or cross large rivers. The pipe segment is the permanent load-bearing structure of the shield tunnel, and it is responsible for resisting soil pressure, groundwater pressure and some special loads. The mechanical performance of the shield pipe segment is directly related to the overall stability, safety and durability of the tunnel structure.

[0003] Based on this, domestic and foreign methods mainly use numerical calculation analysis, scaled test and prototype loading test to carry out research on the mechanical properties of pipe segments; for numerical calculation analysis, the calculation model greatly simplifies the pipe segment structure, and the key calculation parameters of the model are difficult to obtain accurately, and the calculation results are difficult to truly reflect the mechanical state of the pipe segment; the scaled test also simplifies the pipe segment model. Due to issues such as the size and material properties of the scaled pipe segment model, the test results are often quite different from the actual situation; the prototype loading test is the research method that can more truly reflect the mechanical properties of the pipe segment at this stage.

[0004] At present, prototype loading tests of segments in the field of shield tunnel engineering technology are all conducted in a flat-lying manner based on indoor laboratory platforms. However, since the flat-lying segment prototype loading tests cannot take into account the important influence of the deadweight of the segment structure on the mechanical state of the segment ring, the accuracy of the test results still needs further review and evaluation. Summary of the Invention

[0005] In view of the above-mentioned defects or deficiencies in the prior art, the present invention aims to provide a prototype loading test device and test method for shaft-type shield segments.

[0006] In a first aspect, the present invention provides a prototype loading test device for a shaft-type shield segment, comprising:

[0007] A support body, the support body being used to support a test ring segment group, the test ring segment group comprising at least one test ring segment distributed and arranged along a first direction and interconnected, the test ring segment being a shield segment, each of the test ring segments being composed of a plurality of arc-shaped segments, the axis extension direction of the test ring segment being the first direction; the first direction being a horizontal direction;

[0008] A reaction frame body, wherein the reaction frame body includes at least one reaction frame group distributed along the first direction, each reaction frame group is arranged corresponding to the test ring segment, each reaction frame group includes at least one reaction frame, each reaction frame includes two columns distributed along the second direction, the bottom ends of the two columns are connected to the support body, and a first space is formed between the columns of each reaction frame group and the support body, the first space is used to place the test ring segment, and the second direction is perpendicular to the first direction;

[0009] A load loading system, the load loading system comprising at least one loading mechanism corresponding to the reaction frame, each loading mechanism comprising:

[0010] A radial loading assembly, wherein the radial loading assembly is used to apply an equivalent bending moment to the test ring segment, wherein the equivalent bending moment is used to simulate the bending moment to which the shield segment is subjected in actual working conditions;

[0011] A hoop loading assembly, wherein the hoop loading assembly is used to apply an equivalent axial force to the test ring segment, wherein the equivalent axial force is used to simulate the axial force to which the shield segment is subjected in actual working conditions;

[0012] A hoisting and loading assembly, wherein the hoisting and loading assembly is used to apply a pulling force to the test ring segment to achieve deadweight balance of the test ring segment;

[0013] A monitoring component is used to measure the structural internal force and deformation of the test ring segment.

[0014] According to the technical solution provided by the present invention, the test device is arranged in a vertical shaft structure, and the vertical shaft structure includes two vertical shaft walls distributed along the second direction. The two columns of each reaction frame are connected to the corresponding vertical shaft walls at ends away from each other; the test ring segment group is assembled and formed by a shield machine.

[0015] According to the technical solution provided by the present invention, the reaction frame also includes two top inclined beams, one end of the two top inclined beams is connected, and the other end is respectively connected to the two columns away from the support body end of the support, and a first angle is formed between the two top inclined beams, and the opening of the first angle is toward the test ring segment.

[0016] According to the technical solution provided by the present invention, the hoisting and loading assembly includes a hoisting steel strand arranged around the outer wall of the test ring segment close to the support body side of the support, and also includes a hoisting drive unit arranged on the two top inclined beams, the two hoisting drive units are respectively connected to the two ends of the hoisting steel strand, and the two hoisting drive units can synchronously apply a force along a third direction to the test ring segment, and the third direction is perpendicular to the first direction and the second direction.

[0017] According to the technical solution provided by the present invention, the radial loading assembly includes a horizontal loading part arranged on both sides of the test ring segment along the second direction, and a vertical loading part arranged on both sides of the test ring segment along the third direction. The horizontal loading part is used to apply a horizontal force to the test ring segment along the second direction, and the vertical loading part is used to apply a vertical force to the test ring segment along the third direction.

[0018] According to the technical solution provided by the present invention, the hoop loading assembly includes at least one hoop loading part, each of the hoop loading parts includes a hoop steel strand wrapped around the test ring segment, one end of the hoop steel strand is connected to the outer wall of the test ring segment, and the other end is connected to the hoop driving part, and the hoop driving part is used to apply tension to the hoop steel strand.

[0019] According to the technical solution provided by the present invention, the support body includes a base, the top surface of the base is provided with an arc-shaped groove, the arc-shaped groove has an arc-shaped surface matching the test ring segment, two steel rails are provided on the arc-shaped surface, the two steel rails are symmetrically distributed on both sides of the test ring segment along the second direction, and the extension direction of the steel rails is the first direction; the steel rails are used to support the test ring segment.

[0020] According to the technical solution provided by the present invention, a notch is provided on the top of the rail, and the notch is used for the hoop steel strand and the hoisting steel strand to pass through.

[0021] According to the technical solution provided by the present invention, polyethylene plates are pasted on both ends of the test ring segment group along the first direction to reduce the frictional resistance at the boundary positions of the test ring segment.

[0022] In a second aspect, the present invention provides a shaft shield segment prototype loading test method, using the shaft shield segment prototype loading test device as described above, comprising the following steps:

[0023] Obtaining the gravity magnitude and actual load set of the test ring segment, wherein the actual load set includes the top load, lateral top load, the load difference between the lateral top and lateral bottom, and the horizontal resistance of the triangular stratum;

[0024] Calculate the radial concentrated load and the hoop uniformly distributed load based on the actual load set;

[0025] actuating the hoisting and loading assembly according to the magnitude of the gravity to apply a counter-gravity force to the test ring segment in stages, wherein the magnitude of the counter-gravity force is equal to the magnitude of the gravity and the direction is opposite to the direction of gravity;

[0026] actuating a radial loading assembly according to the magnitude of the radial concentrated load to apply radial loads in stages to the test ring segment, and actuating a hoop loading assembly according to the magnitude of the hoop uniformly distributed load to apply hoop uniformly distributed loads in stages circumferentially to the outer wall of the test ring segment;

[0027] The structural internal forces and deformations of the test ring segments are recorded.

[0028] In summary, the present invention proposes a prototype loading test device for a vertical shaft shield segment, comprising a support body for supporting a test ring segment and a reaction frame body placed on both sides of the test ring segment, the reaction frame body being provided with a load loading system comprising a radial loading assembly, a hoop loading assembly, and a hoisting loading assembly; the test ring segment is placed vertically with its axis in the horizontal direction, an equivalent bending moment is applied to the test ring segment by the radial loading assembly, an equivalent axial force is applied to the test ring segment by the hoisting loading assembly, and a lifting force is applied to the test ring segment by the hoisting loading assembly to achieve deadweight balance. The present invention is a standing segment prototype loading test, which simulates the actual stress state of the segment more realistically than the flat-lying test of the prior art; in addition, the present invention achieves deadweight balance through the hoisting loading assembly, which can accurately simulate the deadweight reaction of the segment provided by the stratum in actual working conditions, solves the problem of deadweight reaction concentration in the standing segment prototype loading test, and more realistically simulates the actual stress state of the segment. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 A schematic structural diagram of a prototype loading test device for a shaft-type shield segment provided in Example 1 of the present invention;

[0030] Figure 2 A top view of the test ring segments and shield segments provided in Example 1 of the present invention within the shaft structure;

[0031] Figure 3 Flowchart of the shaft shield segment prototype loading test method provided in Example 2 of the present invention.

[0032] The text annotations in the figure represent:

[0033] 1. Support body; 11. Base; 111. Arc groove; 112. Rail; 113. First groove; 2. Test ring segment group; 21. Test ring segment; 3. Reaction frame; 31. Column; 32. Top oblique beam; 33. Top horizontal beam; 34. Top vertical beam; 4. Radial loading assembly; 41. Triangular bracket; 42. Horizontal loading beam; 43. Horizontal drive unit; 44. Top loading unit; 441. Top loading beam; 442. Top drive unit; 45. Bottom loading unit; 451. Bottom drive unit; 5. Hoop loading assembly; 51. Hoop steel strand; 52. Hoop beam; 6. Hoisting loading assembly; 61. Hoisting steel strand; 62. Hoisting drive unit; 8. Shaft structure; 81. Shaft wall. DETAILED DESCRIPTION

[0034] The present invention will be further described in detail below with reference to the accompanying drawings and examples. It should be understood that the specific embodiments described herein are intended only to illustrate the relevant invention and are not intended to limit the invention. It should also be noted that, for ease of description, only portions relevant to the invention are shown in the accompanying drawings.

[0035] It should be noted that, in the absence of conflict, the embodiments and features of the embodiments of the present invention can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0036] Example 1

[0037] As the technical problem mentioned in the background technology, the present invention proposes a prototype loading test device for shaft shield segments, such as Figure 1 and Figure 2 Shown, including:

[0038] The support body 1 is used to support the test ring segment group 2. The test ring segment group 2 includes at least one test ring segment 21 distributed and arranged along a first direction and connected to each other. The test ring segment 21 is a shield segment. Each test ring segment 21 is composed of multiple arc-shaped segments. The direction of the extended axis of the test ring segment 21 is the first direction; the first direction is the horizontal direction.

[0039] Among them, such as Figure 1 As shown, the first direction is the front-back direction perpendicular to the paper surface. Optionally, the test ring segment group 2 includes three test ring segments 21, and two adjacent test ring segments 21 are connected by bolts.

[0040] The reaction frame body includes at least one reaction frame group distributed along the first direction, each reaction frame group is corresponding to the test ring segment 21, each reaction frame group includes at least one reaction frame 3, each reaction frame 3 includes two columns 31 distributed along the second direction, the bottom ends of the two columns 31 are connected to the support body 1, and a first space is formed between the columns 31 of each reaction frame group and the support body 1. The first space is used to place the test ring segment 21, and the second direction is perpendicular to the first direction;

[0041] The second direction is a horizontal direction. Optionally, the reaction frame group includes two reaction frames 3, that is, each test ring segment 21 corresponds to two reaction frames 3;

[0042] The load loading system includes at least one loading mechanism corresponding to the reaction frame 3, and each loading mechanism includes:

[0043] A radial loading assembly 4 is used to apply an equivalent bending moment to the test ring segment 21. The equivalent bending moment is used to simulate the bending moment to which the shield segment is subjected in actual working conditions.

[0044] The hoop loading assembly 5 is used to apply an equivalent axial force to the test ring segment 21. The equivalent axial force is used to simulate the axial force to which the shield segment is subjected in actual working conditions.

[0045] A hoisting and loading assembly 6 is used to apply a pulling force to the test ring segment 21 to achieve weight balance of the test ring segment 21;

[0046] In actual working conditions, shield segments are subject to bending moments due to various factors, such as surrounding soil and water pressure, uneven settlement, and temperature changes. Axial forces are generated in the axial direction of the shield segments due to the surrounding soil and water pressure, the pressure inside the tunnel, and the interaction between the shield segments. In the test, equivalent bending moments and equivalent axial forces are applied to the test ring segments 21 via the radial loading assembly 4 and the hoop loading assembly 5 to simulate the stress conditions of the shield segments in actual working conditions, thereby enabling testing and evaluation of the segment performance.

[0047] A monitoring component, which is used to measure the structural internal force and deformation of the test ring segment 21;

[0048] Optionally, the monitoring component is a strain gauge, and multiple strain gauges are arranged on the inner and outer surfaces of the test ring segment 21 to measure the structural internal force and deformation of the test ring segment 21. The obtained structural internal force and deformation are used to optimize the segment structure design and evaluate the safety of the segment. This is existing technology and will not be repeated here.

[0049] The present invention is a standing segment prototype loading test. Compared with the lying test in the prior art, it simulates the actual stress state of the segment more realistically. The present invention provides equivalent bending moment and equivalent axial force to the test ring segment 21 through the radial loading component 4 and the hoop loading component 5. The two sets of loading components are loaded independently, and the operation is simple. In addition, the present invention realizes the self-weight balance of the test ring segment 21 through the hoisting loading component 6, which can accurately simulate the self-weight reaction force of the segment provided by the formation in actual working conditions, solves the problem of self-weight reaction force concentration in the standing segment prototype loading test, and more realistically simulates the actual stress state of the segment.

[0050] In a preferred embodiment, the test device is arranged in a vertical shaft structure 8, which includes two vertical shaft walls 81 distributed along the second direction, and the two columns 31 of each reaction frame 3 are connected to the corresponding vertical shaft walls 81 at ends away from each other; the test ring segment group 2 is assembled and formed by a shield machine.

[0051] The shaft structure 8 is a square shield launch shaft. The bottom of the shaft structure 8 includes a reinforced concrete shaft floor. Two embedded steel plates are pre-buried in the shaft floor. These plates are arranged along the second direction on either side of the support body 1. These embedded steel plates are used to connect to the columns 31 of the reaction frames 3. Each reaction frame 3 abuts the shaft wall 81 of the shaft structure 8. By utilizing the existing shaft structure 8 and support body 1 of the shield tunneling project as a test platform and using the existing shield negative ring segments as the test ring segments 21, prototype loading tests can be conducted without affecting on-site shield tunneling construction, reducing the cost of segment prototype loading tests.

[0052] The present invention starts excavation by means of a shield machine, and assembles shield segments in the shaft structure 8 to form a plurality of shield segments connected by bolts. The three shield segments in the middle are selected as the test ring segment group 2, and the bolts between the test ring segment group 2 and the other shield segments are removed; therefore, the test ring segment 21 is the shield segment. The present invention uses a shield machine to complete the assembly, restores the actual assembly form of the shield segments, and uses the construction site as the test site, avoiding the problem of difficulty in finding the site, and can truly reflect the mechanical properties of the segments.

[0053] Specifically, each column 31 and the shaft wall 81 are connected through a column support assembly, and the column support assembly is arranged in the middle of the column 31. The column support assembly includes a column plate arranged at the end of the column 31 away from the test ring segment 21, a threaded screw threadedly connected to the column plate, a ball head connected to the end of the threaded screw away from the column plate, and a shaft wall plate arranged at the end of the shaft wall 81 close to the test ring segment 21; wherein, the extension direction of the threaded screw is the second direction, and its length can be adjusted telescopically; after adjustment, the ball head abuts against the shaft wall plate, and when the column 31 is subjected to a horizontal force, the ball head can ensure that the force can be evenly transmitted to the shaft structure 8 to avoid unbalanced loading.

[0054] In the prior art, since the diameter of the test ring segment 21 is large and the weight of each segment is about 15 tons, even a flat test requires finding a sufficiently large space, and using lifting equipment to complete the assembly of the test ring segment 21. This method has assembly errors, which will have a significant impact on the mechanical state of the segment ring. The present invention uses a shield machine to complete the assembly, avoiding assembly errors, and uses the construction site as a test site, avoiding the problem of difficulty in finding a site, and can truly reflect the mechanical properties of the segment.

[0055] In a preferred embodiment, polyethylene sheets are attached to both ends of the test ring segment group 2 along the first direction to reduce frictional resistance at the boundaries of the test ring segment 21 .

[0056] Among them, the polyethylene plate is pasted in the annular seam. Since the test ring segment 21 will be deformed under the load loading of the load loading system, the polyethylene plate is used to prevent the shield segments on both sides of the test ring segment group 2 from interfering with it.

[0057] In a preferred embodiment, the reaction frame 3 also includes two top inclined beams 32, one end of the two top inclined beams 32 is connected, and the other end is respectively connected to the two columns 31 away from the end of the support body 1, and a first angle is formed between the two top inclined beams 32, and the opening of the first angle is toward the test ring segment 21.

[0058] Among them, the reaction frame 3 structure is a gate-shaped steel frame, which is installed between the test ring segment 21 and the shaft wall 81, and includes a column 31, two top inclined beams 32, a top cross beam 33, and a top vertical beam 34. Among them, the extension direction of the top cross beam 33 is the second direction, and its two ends are respectively connected to the corresponding top inclined beams 32. The extension direction of the top vertical beam 34 is the vertical direction, one end of which is connected to the connection between the two top inclined beams 32, and the other end is connected to the top cross beam 33. The adjacent components are connected by high-strength bolts; the top cross beam 33 and the top inclined beam 32 form a triangular structure, which improves the stability of the reaction frame 3.

[0059] In a preferred embodiment, the support body 1 includes a base 11, and an arc-shaped groove 111 is opened on the top surface of the base 11. The arc-shaped groove 111 has an arc-shaped surface matching the test ring segment 21. Two steel rails 112 are provided on the arc-shaped surface. The two steel rails 112 are symmetrically distributed on both sides of the test ring segment 21 along the second direction, and the extension direction of the steel rails 112 is the first direction; the steel rails 112 are used to support the test ring segment 21.

[0060] Among them, the shield starting base is cast on the bottom plate of the vertical shaft as the base 11, and the extension direction of the base 11 is the first direction. The base 11 includes a first base, a second base and a third base distributed in sequence along the second direction. There is a gap between the three, and the top surfaces of the three have curved surfaces, which together form an arc-shaped curved surface. The first base and the third base are provided with steel rails 112. In addition to supporting the test ring segment 21, the steel rails 112 are also used for the shield machine to move.

[0061] In a preferred embodiment, the lifting and loading assembly 6 includes a lifting steel strand 61 arranged around the outer wall of the test ring segment 21 close to the side of the support body 1, and also includes a lifting drive unit 62 arranged on two top inclined beams 32. The two lifting drive units 62 are respectively connected to the two ends of the lifting steel strand 61. The two lifting drive units 62 can synchronously apply a force along a third direction to the test ring segment 21, and the third direction is perpendicular to the first direction and the second direction.

[0062] Among them, optionally, the lifting drive part 62 is a hollow cylinder, the third direction is the vertical direction, and a fixed steel plate is welded at the horizontal boundary position of the top inclined beam 32 corresponding to the test ring segment 21. The fixed steel plate is arranged at the ends of the two top inclined beams 32 that are far away from each other. The fixed steel plate is placed horizontally, and the lifting drive part 62 is arranged in the middle above the fixed steel plate. A through hole is opened in the center of the fixed steel plate and the top inclined beam 32 and its corresponding position. The lifting steel strand 61 passes through the through holes of the top inclined beam 32 and the fixed steel plate and is connected to the hollow cylinder. Through the synchronous action of the two hollow cylinders, the test ring segment 21 can be moved up and down in the vertical direction.

[0063] In a preferred embodiment, the radial loading assembly 4 includes a horizontal loading part provided on both sides of the test ring segment 21 along the second direction, and a vertical loading part provided on both sides of the test ring segment 21 along the third direction. The horizontal loading part is used to apply a horizontal force to the test ring segment 21 along the second direction, and the vertical loading part is used to apply a vertical force to the test ring segment 21 along the third direction.

[0064] Wherein, the horizontal loading part includes:

[0065] Triangular bracket 41, which is located in the middle of the column 31 near the end of the test ring segment 21. Triangular bracket 41 includes a horizontal bracket and an oblique bracket. One end of the horizontal bracket is connected to the column 31, and the other end is connected to the high end of the oblique bracket. The low end of the oblique bracket is connected to the column 31.

[0066] A horizontal loading beam 42 is provided on the outer wall of the test ring segment 21 , and extends in a vertical direction and is tangent to the outer wall of the test ring segment 21 ;

[0067] The horizontal driving part 43 is placed horizontally on the horizontal support. Optionally, the horizontal driving part 43 is a jack, the bottom of the jack is connected to the column 31 through a flange, and the top of the jack is in contact with the horizontal loading beam 42.

[0068] Wherein, the vertical loading part includes:

[0069] A top loading unit 44 includes a top loading beam 441 disposed on the top of the test ring segment 21. The top loading beam 441 is tangent to the top of the test ring segment 21. The top loading beam 441 also includes a top driving unit 442. The bottom of the top driving unit 442 is connected to the top cross beam 33, and the other end is in contact with the top loading beam 441. Optionally, the top driving unit 442 is a hydraulic jack.

[0070] The bottom loading part 45 includes a bottom loading beam arranged at the bottom of the test ring segment 21, and the bottom loading beam is tangent to the bottom of the test ring segment 21. It also includes a bottom driving part 451. Optionally, the bottom driving part 451 is a hydraulic jack, which is retractable and used to apply a load to the bottom of the test ring segment 21; a first groove 113 is provided on the second base, and in the initial state, the hydraulic jack is placed in the first groove 113. When a load is applied to the test ring segment 21, the piston rod of the hydraulic jack extends out of the first groove 113 and abuts against the bottom loading beam.

[0071] When the test ring segment group 2 includes multiple test ring segments 21, it includes multiple radial loading assemblies 4, all horizontal loading beams 42 on the left side of the test ring segment group 2 are integrated into one, and all horizontal loading beams 42 on the right side, all top loading beams 441 and all bottom loading beams are respectively integrated into one, and the first groove 113 is strip-shaped, and all bottom driving parts 451 are placed in the first groove 113.

[0072] Furthermore, a limiting groove is provided on the top crossbeam 33. The limiting groove opens toward the test ring segment 21 and extends in the first direction. A chute is provided on the bottom wall of the limiting groove. The chute extends in the first direction. A buckle slider matching the chute is provided on the top of the hydraulic jack. The buckle slider can drive the hydraulic jack to slide in the chute. Once in place, it is fixed to the chute by the buckle structure of the buckle slider. A limiting baffle is provided at the opening of the limiting groove. A limiting opening is provided on the limiting baffle. When the hydraulic jack is not extended, it is placed in the limiting groove. When a load is applied to the test ring segment 21, the piston of the hydraulic jack abuts against the top of the test ring segment 21 through the limiting opening. The limiting baffle avoids the risk of the hydraulic jack falling.

[0073] In a preferred embodiment, the hoop loading assembly 5 includes at least one hoop loading part, each hoop loading part includes a hoop steel strand 51 wrapped around the test ring segment 21, one end of the hoop steel strand 51 is connected to the outer wall of the test ring segment 21, and the other end is connected to the hoop driving part, which is used to apply tension to the hoop steel strand 51.

[0074] Because the internal forces of the test ring segment 21 are relatively large, each test ring segment 21 is loaded with multiple hoop loading units. Optionally, each test ring segment 21 employs four hoop loading units. A layer of rubber is sheathed around the outer surface of the hoop steel strand 51, and lubricating grease is filled between the rubber and the hoop steel strand 51. Each hoop loading unit also includes a hoop beam 52, which extends radially outward from the outer wall of the test ring segment 21 and has a steel strand passage hole in the middle. A hoop drive unit is provided on the hoop beam 52. Optionally, the hoop drive unit is a hollow cylinder. One end of the hoop steel strand 51 is fixed to the hoop beam 52 using a steel strand tool anchor, and the other end is wrapped around the test ring segment 21, passed through the steel strand passage hole, and connected to the hollow cylinder. Due to the limited width of the test ring segment 21, multiple hollow cylinders cannot be accommodated. Therefore, two hollow cylinders are placed at 180-degree diagonal positions.

[0075] In a preferred embodiment, a slot is formed on the top of the steel rail 112 for allowing the hoop steel strand 51 and the hoisting steel strand 61 to pass through the slot.

[0076] Among them, the number of slots is the same as the number of hoop steel strands 51 surrounding the outside of the test ring segment 21 and the number of lifting steel strands 61 wound around the outer wall of the test ring segment 21. Optionally, each test ring segment 21 is wrapped with 4 hoop steel strands 51 and one lifting steel strand 61, so the number of slots corresponding to each test ring segment 21 is 5.

[0077] Example 2

[0078] Based on Example 1, the present invention provides a test method for a shaft shield segment prototype loading test device, such as Figure 3 As shown, the following steps are included:

[0079] S100. Obtain the gravity magnitude and actual load set of the test ring segment 21, the actual load set including the top load, lateral top load, lateral top and lateral bottom load difference, and triangular stratum horizontal resistance under actual working conditions.

[0080] Before step S100, the following steps are also included:

[0081] S010. Construct the shield starting shaft and pre-embed steel plates at the corresponding positions on the shaft floor;

[0082] S020. Cast the shield starting base as the base 11 in the shaft bottom plate, and reserve a first groove 113 on the second base of the base 11, install the rail 112 on the first and third bases, and install the bottom drive portion 451 in the first groove 113;

[0083] S030 prefabricated test ring segment 21, the test ring segment 21 is provided with a monitoring assembly inside and outside, and the test ring segment group 2 is pasted with polyethylene sheets at both ends;

[0084] S040. The shield begins excavation and assembles the test ring segment 21 and other shield segments within the shaft structure 8. The adjacent segments are connected by bolts along the longitudinal seams.

[0085] S050. Install the reaction frame and load-loading system;

[0086] S060. After the test ring segment 21 is no longer affected by the thrust of the shield machine, remove the connecting bolts between the test ring segment 21 and the adjacent shield segment and start the test.

[0087] Optionally, before the shield machine is assembled, the weight of each segment can be obtained by a weighing device, and then the gravity of the test ring segment 21 can be calculated based on the number of segments required to assemble the test ring segment 21. The test personnel input the gravity into the control unit of the test device.

[0088] Furthermore, obtaining the actual load set includes the following steps:

[0089] S101 obtains the centroid radius of the test ring segment 21 and the soil and water information of the tunnel where the shaft structure 8 is located;

[0090] Among them, the centroid radius can be calculated by measuring the inner diameter and outer diameter of the test ring segment 21, and the soil information and water information can be obtained through hydrogeological survey. The soil information includes the type of soil, thickness of the overburden layer, stratum properties, loose zone width, etc. The water information includes the radial water pressure along the tunnel, the net water head height at the top of the tunnel, etc.

[0091] S102. Obtaining the actual load set based on the centroid radius, soil information, and water information;

[0092] Among them, the actual load set can be obtained by searching relevant specifications based on the centroid radius, soil information and water information;

[0093] S200. Calculate the radial concentrated load and the hoop uniform load based on the actual load set; calculate the hoop uniform load based on the actual load set using the following formula:

[0094] Formula (1)

[0095] Where, F h is the uniformly distributed load on the hoop, q c is the lateral top load; q s is the load difference between the lateral top and lateral bottom; q k is the horizontal resistance of the triangular stratum.

[0096] The radial concentrated load includes the horizontal concentrated load and the vertical concentrated load. The vertical concentrated load and the horizontal concentrated load are calculated based on the actual load set. The horizontal concentrated load and the vertical concentrated load can be obtained by the following formula:

[0097] Formula (2)

[0098] in: Formula (3)

[0099] Where: F z is the vertical concentrated load; F s is the horizontal concentrated load; q d is the top load; q c is the lateral top load; q s is the load difference between the lateral top and lateral bottom; q k is the horizontal resistance of the triangular stratum; R is the centroid radius;

[0100] In addition: the above formula involves a 、 b 、 c 、 d They are all coefficients, which serve to simplify the formula.

[0101] Among them, the loads applied to the test ring segment 21 by the horizontal loading parts on both sides along the second direction are in opposite directions, and the load magnitudes are equal to the horizontal concentrated load magnitude; the loads applied to the test ring segment 21 by the top loading part 44 and the bottom loading part 45 along the third direction are in opposite directions, and the load magnitudes are equal to the vertical concentrated load magnitude.

[0102] S300. Start the hoisting loading assembly 6 according to the gravity, and apply the anti-gravity force to the test ring segment 21 in a graded manner. The anti-gravity force is equal to the gravity and in the opposite direction to the gravity.

[0103] Among them, after the test ring segment group 2, the reaction frame body and the load loading system are assembled, the gravity of the test ring segment 21 is obtained by the control unit, and the horizontal concentrated load size and the vertical concentrated load size, as well as the hoop uniform load size are calculated. The control unit sends a lifting instruction to each lifting and loading component 6. After receiving the lifting instruction, all the lifting and loading components 6 synchronously pull the lifting steel strands 61 through the hollow cylinders of each lifting and loading component 6 to achieve the deadweight balance of the test ring segment 21;

[0104] S400. The radial loading assembly 4 is activated according to the magnitude of the radial concentrated load to apply a graded radial load to the test ring segment 21, and the hoop loading assembly 5 is simultaneously activated according to the magnitude of the hoop uniform load to apply a graded circumferential hoop uniform load to the outer wall of the test ring segment 21;

[0105] After the hoisting and loading assembly 6 lifts the test ring segment group 2, the test ring segment group 2 is separated from the rail 112, and then a load is applied to the test ring segment 21 through the radial loading assembly 4 and the hoop loading assembly 5, simulating the stress conditions of the shield segment in actual working conditions. Specifically, after the hoisting is completed, the hoisting and loading assembly 6 sends a hoisting completion signal to the control unit. After receiving the signal, the control unit sends a start signal to the top drive unit 442, the bottom drive unit 451, the horizontal drive unit 43, and the hoop drive unit. After receiving the signal, the top drive unit 442, the bottom drive unit 451, the horizontal drive unit 43, and the hoop drive unit perform graded loading on the test ring segment 21.

[0106] S500. Record the internal force and deformation of the test ring segment 21.

[0107] In summary, the present invention has the following beneficial effects:

[0108] By using the existing shaft structure 8 and support body 1 of the shield project as a test platform and the existing shield segments as test objects, prototype loading tests can be carried out without affecting on-site shield construction, thus reducing the cost of segment prototype loading tests.

[0109] This test is a standing segment prototype loading test. The test ring segment 21 is assembled by a shield machine. This solves the problem that the existing lying segment prototype loading test cannot consider the effect of the deadweight of the segment structure and the assembly error on the mechanical state of the segment ring. It simulates the actual stress condition of the segment more realistically.

[0110] The self-weight balance of the test ring segment 21 is achieved by hoisting the loading assembly 6, which can accurately simulate the self-weight reaction of the segment provided by the formation in actual working conditions, and solve the problem of self-weight reaction concentration in the standing segment prototype loading test;

[0111] The load borne by the reaction frame 3 is much smaller than the reaction frame 3 used in the laboratory flat-lying pipe segment loading test, and the vertical shaft structure 8 can be used as support. Therefore, the internal force of the reaction frame 3 is relatively small, the construction cost is low, and the structure is simple.

[0112] The above description is merely a preferred embodiment of the present invention and an illustration of the technical principles employed. Those skilled in the art should understand that the scope of the invention is not limited to the technical solutions formed by the specific combination of the above-mentioned technical features, but also encompasses other technical solutions formed by any combination of the above-mentioned technical features or their equivalents without departing from the inventive concept. For example, a technical solution formed by replacing the above-mentioned features with (but not limited to) technical features with similar functions disclosed in the present invention.

Claims

1. A prototype loading test device for shaft-type shield segments, characterized in that: include: A support body (1), the support body (1) is used to support a test ring segment group (2), the test ring segment group (2) includes at least one test ring segment (21) distributed and arranged along a first direction and connected to each other, the test ring segment (21) is a shield segment, each of the test ring segments (21) is composed of a plurality of arc segments, the axis extension direction of the test ring segment (21) is the first direction, and the first direction is a horizontal direction; A reaction frame body, wherein the reaction frame body includes at least one reaction frame group distributed along the first direction, each reaction frame group is corresponding to the test ring segment (21), each reaction frame group includes at least one reaction frame (3), each reaction frame (3) includes two columns (31) distributed along the second direction, the bottom ends of the two columns (31) are connected to the support body (1), a first space is formed between the columns (31) of each reaction frame group and the support body (1), the first space is used to place the test ring segment (21), and the second direction is perpendicular to the first direction; the reaction frame (3) also includes two top inclined beams (32), one end of the two top inclined beams (32) is connected, and the other end is respectively connected to the two columns (31) away from the support body (1), a first angle is formed between the two top inclined beams (32), and the first angle opens toward the test ring segment (21); A load loading system, the load loading system comprising at least one loading mechanism corresponding to the reaction frame (3), each loading mechanism comprising: A radial loading assembly (4), the radial loading assembly (4) is used to apply an equivalent bending moment to the test ring segment (21), the equivalent bending moment being used to simulate the bending moment to which the shield segment is subjected in actual working conditions; A hoop loading assembly (5), the hoop loading assembly (5) is used to apply an equivalent axial force to the test ring segment (21), the equivalent axial force being used to simulate the axial force to which the shield segment is subjected in actual working conditions; A hoisting and loading assembly (6), wherein the hoisting and loading assembly (6) is used to apply a pulling force to the test ring segment (21) to achieve the self-weight balance of the test ring segment (21); the hoisting and loading assembly (6) includes a hoisting steel strand (61) arranged around the outer wall of the test ring segment (21) near the side of the support body (1), and also includes a hoisting drive unit (62) provided on the two top inclined beams (32), the two hoisting drive units (62) are respectively connected to the two ends of the hoisting steel strand (61), and the two hoisting drive units (62) can synchronously apply a force along a third direction to the test ring segment (21), wherein the third direction is perpendicular to the first direction and the second direction; A monitoring component, the monitoring component is used to measure the structural internal force and deformation of the test ring segment (21); The test device is arranged in a shaft structure (8), the shaft structure (8) includes two shaft walls (81) distributed along the second direction, and the two columns (31) of each reaction frame (3) are connected to the corresponding shaft wall (81) at ends away from each other; the test ring segment group (2) is assembled by a shield machine; the existing shaft structure (8) and the support body (1) of the shield project are used as a test platform, and the existing shield segments are used as test objects. The prototype loading test is carried out without affecting the on-site shield construction, thereby reducing the cost of the segment prototype loading test.

2. The shaft shield segment prototype loading test device according to claim 1 is characterized in that: The radial loading assembly (4) includes a horizontal loading portion provided on both sides of the test ring segment (21) along the second direction, and a vertical loading portion provided on both sides of the test ring segment (21) along the third direction, wherein the horizontal loading portion is used to apply a horizontal force to the test ring segment (21) along the second direction, and the vertical loading portion is used to apply a vertical force to the test ring segment (21) along the third direction.

3. The shaft shield segment prototype loading test device according to claim 1 is characterized in that: The hoop loading assembly (5) includes at least one hoop loading part, each of the hoop loading parts includes a hoop steel strand (51) wound around the test ring segment (21), one end of the hoop steel strand (51) is connected to the outer wall of the test ring segment (21), and the other end is connected to a hoop driving part, and the hoop driving part is used to apply tension to the hoop steel strand (51).

4. The shaft shield segment prototype loading test device according to claim 3 is characterized in that: The support body (1) includes a base (11), a top surface of the base (11) is provided with an arc-shaped groove (111), the arc-shaped groove (111) has an arc-shaped surface matching the test ring segment (21), two steel rails (112) are provided on the arc-shaped surface, the two steel rails (112) are symmetrically distributed on both sides of the test ring segment (21) along the second direction, and the extension direction of the steel rails (112) is the first direction; the steel rails (112) are used to support the test ring segment (21).

5. The shaft shield segment prototype loading test device according to claim 4 is characterized in that: A notch is provided on the top of the steel rail (112), and the notch is used for the hoop steel strand (51) and the hoisting steel strand (61) to pass through.

6. The shaft shield segment prototype loading test device according to claim 1 is characterized in that: Polyethylene plates are adhered to both ends of the test ring segment group (2) along the first direction, so as to reduce the frictional resistance at the boundary positions of the test ring segment (21).

7. A shaft shield segment prototype loading test method, using the shaft shield segment prototype loading test device according to any one of claims 1 to 6, characterized in that: The steps include: Obtaining the gravity magnitude and actual load set of the test ring segment (21), wherein the actual load set includes the top load, the lateral top load, the load difference between the lateral top and the lateral bottom, and the horizontal resistance of the triangular stratum that the shield segment is subjected to in actual working conditions; Calculate the radial concentrated load and the hoop uniformly distributed load based on the actual load set; According to the magnitude of the gravity, the hoisting loading assembly (6) is activated to apply a counter-gravity force to the test ring segment (21) in stages, wherein the magnitude of the counter-gravity force is equal to the magnitude of the gravity and the direction is opposite to the direction of gravity; Starting the radial loading assembly (4) according to the magnitude of the radial concentrated load to apply radial loads in stages to the test ring segment (21), and synchronously starting the hoop loading assembly (5) according to the magnitude of the hoop uniform load to apply hoop uniform loads in stages to the outer wall of the test ring segment (21); The structural internal forces and deformations of the test ring segment (21) are recorded.

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