CN114279947B - Experimental device and method for researching shield tunnel segment performance degradation mechanism - Google Patents
Experimental device and method for researching shield tunnel segment performance degradation mechanism Download PDFInfo
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- FAPWRFPIFSIZLT-UHFFFAOYSA-M Sodium chloride Chemical compound [Na+].[Cl-] FAPWRFPIFSIZLT-UHFFFAOYSA-M 0.000 claims abstract description 46
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Abstract
The invention belongs to the technical field of shield tunnel durability tests, and discloses an experimental device and method for researching a shield tunnel segment performance degradation mechanism, wherein the experimental device comprises a base, a cover plate, a soil pressure loading assembly, a water tank and a constant current meter, an arc segment concave arc is downwards arranged on a sliding rail of the base, one end of the arc segment is hinged with the sliding rail, and the other end of the arc segment is in sliding connection with the sliding rail; the cover plate is of a shell structure with one end open, the cover plate is movably connected to a bracket on the base, and the open end of the cover plate is covered on the surface of the arc-shaped duct piece to seal so as to form a pressurizing bin; the soil pressure loading assembly loads simulated soil pressure to the arc-shaped duct piece, the water tank provides sodium chloride solution for the pressurizing bin, the positive electrode of the constant current instrument is connected with the stressed main rib of the arc-shaped duct piece, and the negative electrode of the constant current instrument is arranged in the pressurizing bin. The invention can carry out durability test in the environment that the arc-shaped duct piece is corroded by soil pressure, high water pressure and ions, and is convenient for researching the degradation mechanism of the performance of the shield tunnel duct piece and the evolution rule of the stress performance of the shield tunnel lining structure in the service period.
Description
Technical Field
The invention relates to the technical field of shield tunnel durability tests, in particular to an experimental device and method for researching a shield tunnel segment performance degradation mechanism.
Background
The shield method has the advantages of small influence on surrounding environment, strong adaptability to complex geological conditions, safe and quick construction and the like, and becomes one of the common adopted methods for tunnels such as urban subways, river crossing, sea crossing and the like in China. For shield tunnels adopting reinforced concrete segments, the problem of structural corrosion durability under the coupling action of long-time erosion environment and complex structural load is increasingly remarkable, and the problems comprise phenomena such as corrosion of inner row steel bars, exposed parts of connecting bolts and steel pull rods of tunnel structures, stripping of concrete protective layers of the segments, leakage at segment reserved holes and joints, and the like, so that the generated tunnel facilities have huge maintenance cost and huge maintenance cost.
The durability problem of the shield tunnel occurs due to the complex working environment, complex load conditions and construction or other factors, and the existing durability research and test mainly takes the influence of harmful ion erosion in the environment as a main factor to model and test, and the durability problem of the shield tunnel possibly caused by the combined action of the load conditions is tested and researched.
Disclosure of Invention
The invention aims to provide an experimental device and method for researching a shield tunnel segment performance degradation mechanism so as to realize a durability test of the shield tunnel segment under the coupling effect of chloride ion erosion and high-pressure water and research the shield tunnel segment performance degradation mechanism and the stress performance evolution rule of a shield tunnel lining structure in the service period.
To achieve the purpose, the invention adopts the following technical scheme:
the invention firstly relates to an experimental device for researching a shield tunnel segment performance degradation mechanism, which comprises the following components:
the device comprises a base, wherein a sliding rail and a bracket are arranged on the base, an arc-shaped duct piece of the shield tunnel duct piece is selected, a concave arc of the arc-shaped duct piece is downwards arranged on the sliding rail, one end of the arc-shaped duct piece is hinged with the sliding rail, and the other end of the arc-shaped duct piece is connected with the sliding rail in a sliding manner;
the cover plate is of a shell structure with one end open, the cover plate is movably connected to the bracket, and the open end of the cover plate is covered on one side of the convex arc of the arc-shaped duct piece and is sealed with the surface of the convex arc to form a pressurizing bin;
the soil pressure loading assembly comprises a pressure head and a soil pressure driving piece, the soil pressure driving piece is arranged on the support, the output end of the soil pressure driving piece is connected with the pressure head, and the pressure head is arranged in the pressure bin and is in contact with the convex arc surface of the arc-shaped duct piece so as to load simulated soil pressure;
the water tank is internally provided with sodium chloride solution, and is communicated with the pressurizing bin through a water pipe;
and the positive electrode of the constant current instrument is connected with the stressed main rib of the arc-shaped duct piece, and the negative electrode of the constant current instrument is arranged in the pressurizing bin.
Optionally, the experimental device for researching the performance degradation mechanism of the shield tunnel segment further comprises a rubber ring, wherein the rubber ring is circumferentially arranged around the opening end of the cover plate and can be in sealing contact with the convex arc surface of the arc segment to form the pressurizing bin.
Optionally, the experimental device for researching the shield tunnel segment performance degradation mechanism further comprises a hydraulic driving piece, wherein the hydraulic driving piece is arranged at the end part of the arc segment, the output end of the hydraulic driving piece is stopped against the arc segment, and the hydraulic driving piece is fixed on the base.
Optionally, the cover plate is connected with the support through a plurality of telescopic rods, and a plurality of telescopic rods can drive the cover plate to lift under the drive of the cover plate driving piece.
Optionally, the pressure head includes at least two mutually parallel depression bars, at least two the depression bars are followed the width direction setting of arc section of jurisdiction and symmetry set up on the protruding arc of arc section of jurisdiction.
Optionally, the experimental device for shield tunnel segment performance degradation mechanism research still includes image acquisition device, reinforcing bar corrosion degree detector, acoustic emission sensor and foil gage, image acquisition device is equipped with two at least, locates respectively the side and the bottom surface of arc section of jurisdiction, reinforcing bar corrosion degree detector's probe connect in the atress main muscle of arc section of jurisdiction, acoustic emission sensor with the foil gage is all located the concave arc surface of arc section of jurisdiction.
Optionally, the experimental device for researching the shield tunnel segment performance degradation mechanism further comprises a chloride ion concentration measuring instrument, and a probe of the chloride ion concentration measuring instrument is arranged in the pressurizing bin and used for detecting the concentration of chloride ions in the pressurizing bin.
Optionally, the experimental device for researching the shield tunnel segment performance degradation mechanism further comprises a booster pump, wherein the booster pump is arranged on the water delivery pipe to pressurize the sodium chloride solution and convey the sodium chloride solution to the pressurizing bin.
According to the experimental device for researching the shield tunnel segment performance degradation mechanism provided by the invention, the invention also provides an experimental method for researching the shield tunnel segment performance degradation mechanism, which comprises the following steps:
s1, connecting an electrified lead with a stressed main rib of an arc-shaped duct piece and extending out of the arc-shaped duct piece to be connected with the positive electrode of a constant current instrument to form an anode, and arranging a stainless steel wire mesh in a target corrosion area in a pressurizing bin and connecting the stainless steel wire mesh with the negative electrode of the constant current instrument to form a cathode;
s2, prefabricating initial cracks at the convex arc top and the hoisting hole of the arc-shaped duct piece, arranging an acoustic emission sensor probe and a strain gauge on the concave arc surface of the arc-shaped duct piece, and arranging an image acquisition device on the side surface of the arc-shaped duct piece and below the concave arc respectively;
s3, pressurizing the convex arc surface of the arc-shaped duct piece by the soil pressure loading assembly;
s4, after the arc-shaped duct piece is stable, a cover plate is covered on the convex arc surface of the arc-shaped duct piece and sealed to form a pressurizing bin, then sodium chloride solution is injected into the pressurizing bin at high pressure, and initial deformation data and initial crack data of the arc-shaped duct piece are recorded;
s5, starting the constant current instrument, controlling the current, and simulating the process of bearing high water pressure and chloride ion corrosion of the arc-shaped duct piece;
s6, performing a bending resistance test on the corroded arc-shaped duct piece to obtain the residual bearing capacity of the arc-shaped duct piece.
Optionally, step S5 further includes a step of monitoring the concentration of the chloride ions, and controlling the concentration of the chloride ions.
The invention has the beneficial effects that:
according to the experimental device for researching the shield tunnel segment performance degradation mechanism, the soil pressure loading assembly is arranged to simulate the soil pressure environment suffered by the shield tunnel segment, the water tank is arranged to inject sodium chloride solution into the pressurizing bin to simulate the high water pressure environment suffered by the shield tunnel segment, and the constant current instrument is arranged to simulate the chloride ion erosion environment suffered by the shield tunnel segment, so that the experimental device provided by the invention can realize the durability test of the shield tunnel segment under the coupling effect of chloride ion erosion and high pressure water, and is convenient for researching the shield tunnel segment performance degradation mechanism and the stress performance evolution rule of the shield tunnel lining structure in the service period.
According to the experimental method for researching the shield tunnel segment performance degradation mechanism, the accelerated corrosion test of the arc segment is carried out in the environment that the arc segment is corroded by soil pressure, high water pressure and ions, and the residual bearing capacity of the arc segment is measured after the test, so that the shield tunnel segment performance degradation mechanism and the stress performance evolution rule of the shield tunnel lining structure in the service period can be researched.
Drawings
FIG. 1 is a schematic diagram of the whole structure of an experimental device for researching the shield tunnel segment performance degradation mechanism;
FIG. 2 is a schematic diagram of connection between a constant current meter and an arc-shaped duct piece in an experimental device for researching a shield tunnel duct piece performance degradation mechanism;
fig. 3 is a flow chart of an experimental method for researching a shield tunnel segment performance degradation mechanism.
In the figure:
100. arc-shaped duct pieces;
1. a base; 11. a slide rail; 12. a bracket;
2. a cover plate; 21. a pressurized bin; 22. a telescopic rod; 23. a cover plate driving member;
3. a soil pressure loading assembly; 31. a pressure head; 32. a soil pressure driving member; 4. a water tank; 41. a water pipe; 5. a constant current meter; 6. and a hydraulic driving member.
Detailed Description
The invention is described in further detail below with reference to the drawings and examples. It is to be understood that the specific embodiments described herein are merely illustrative of the invention and are not limiting thereof. It should be further noted that, for convenience of description, only some, but not all of the structures related to the present invention are shown in the drawings.
In the description of the present invention, unless explicitly stated and limited otherwise, the terms "connected," "connected," and "fixed" are to be construed broadly, and may be, for example, fixedly connected, detachably connected, or integrally formed; can be mechanically or electrically connected; can be directly connected or indirectly connected through an intermediate medium, and can be communicated with the inside of two elements or the interaction relationship of the two elements. The specific meaning of the above terms in the present invention can be understood as appropriate by those of ordinary skill in the art.
In the present invention, unless expressly stated or limited otherwise, a first feature "above" or "below" a second feature may include both the first and second features being in direct contact, as well as the first and second features not being in direct contact but being in contact with each other through additional features therebetween. Moreover, a first feature being "above," "over" and "on" a second feature includes the first feature being directly above and obliquely above the second feature, or simply indicating that the first feature is higher in level than the second feature. The first feature being "under", "below" and "beneath" the second feature includes the first feature being directly under and obliquely below the second feature, or simply means that the first feature is less level than the second feature.
In the description of the present embodiment, the terms "upper", "lower", "left", "right", and the like are orientation or positional relationships based on those shown in the drawings, merely for convenience of description and simplicity of operation, and do not indicate or imply that the apparatus or elements referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as limiting the invention. Furthermore, the terms "first," "second," and the like, are used merely for distinguishing between descriptions and not for distinguishing between them. The term "plurality" should be understood as more than two.
The invention provides an experimental device for researching a shield tunnel segment performance degradation mechanism, and aims to realize a durability test of a shield tunnel segment under the coupling effect of chloride ion erosion and high-pressure water so as to research the shield tunnel segment performance degradation mechanism and the stress performance evolution rule of a shield tunnel lining structure in the service period.
1-2, an experimental device for researching a shield tunnel segment performance degradation mechanism comprises a base 1, a cover plate 2, a soil pressure loading assembly 3, a water tank 4 and a constant current meter 5, wherein a sliding rail 11 and a bracket 12 are arranged on the base 1, one section of arc segment 100 of the shield tunnel segment is selected, the concave arc of the arc segment 100 is downwards arranged on the sliding rail 11, one end of the arc segment 100 is hinged with the sliding rail 11, and the other end of the arc segment 100 is in sliding connection with the sliding rail 11; the cover plate 2 is of a shell structure with one end open, the cover plate 2 is movably connected to the bracket 12, and the open end of the cover plate 2 is covered on one side of the convex arc of the arc-shaped duct piece 100 and is sealed with the surface of the convex arc to form a pressurizing bin 21; the soil pressure loading assembly 3 comprises a pressure head 31 and a soil pressure driving piece 32, the soil pressure driving piece 32 is arranged on the bracket 12, the output end of the soil pressure driving piece 32 is connected with the pressure head 31, and the pressure head 31 is arranged in the pressurizing bin 21 and is contacted with the convex arc surface of the arc-shaped duct piece 100 to load simulated soil pressure; the water tank 4 is filled with sodium chloride solution, and the water tank 4 is communicated with the pressurizing bin 21 through a water pipe 41; the positive electrode of the constant current meter 5 is connected with the stressed main rib of the arc-shaped duct piece 100, and the negative electrode is arranged in the pressurizing bin 21.
In this embodiment, as shown in fig. 1, a segment of an arc segment 100 of a shield tunnel segment is selected, and the arc segment 100 is obtained by casting concrete and stressing a main rib. The section department at both ends is equipped with articulated seat, articulates on base 1, specifically can articulate on slide rail 11 or support 12 with fixed displacement, and the other end of arc section of jurisdiction 100 can slide relatively between with slide rail 11, can obtain the deformation and the displacement of arc section of jurisdiction 100 under the simulated soil pressure when the convex arc surface of arc section of jurisdiction 100 has been applyed. The cover plate 2 has the same radian as the arc-shaped duct piece 100 at the opening end so as to completely cover and seal the space between the two, and in the experiment, the opening end of the cover plate 2 is downwards buckled on the arc-shaped duct piece 100, and the inner side surface of the top opposite to the opening end is contacted with the outer wall of the convex arc top of the arc-shaped duct piece 100 so as to be in compression joint with the arc-shaped duct piece 100. The sodium chloride solution stored in the water tank 4 is filled into the pressurizing bin 21, so that the high water pressure environment of the shield tunnel segment can be simulated, and the specific pressure value can be set according to the experimental working condition.
According to the experimental device for researching the shield tunnel segment performance degradation mechanism, the soil pressure loading assembly 3 is arranged to simulate the soil pressure environment suffered by the shield tunnel segment, the water tank 4 is arranged to inject sodium chloride solution into the pressurizing bin 21 to simulate the high water pressure environment suffered by the shield tunnel segment, and the constant current instrument 5 is arranged to simulate the chloride ion erosion environment suffered by the shield tunnel segment, so that the experimental device provided by the invention can realize the durability test of the shield tunnel segment under the coupling effect of chloride ion erosion and high pressure water, and is convenient for researching the shield tunnel segment performance degradation mechanism and the stress performance evolution rule of the shield tunnel lining structure in the service period.
Optionally, the experimental device for studying the performance degradation mechanism of the shield tunnel segment further comprises a rubber ring which is circumferentially arranged around the opening end of the cover plate 2 and can be in sealing contact with the convex arc surface of the arc segment 100 to form the pressurizing bin 21.
It should be noted that, the rubber ring is used for sealing the connection gap between the opening end of the cover plate 2 and the arc-shaped duct piece 100, so as to avoid the pressure release caused by the leakage of the sodium chloride solution in the pressurizing bin 21, and influence the test precision. The rubber ring is an elastic piece, and when the arc-shaped duct piece 100 is displaced or deformed under the action of simulated soil pressure, the rubber ring can always keep the sealing of the pressurizing bin 21.
Optionally, the experimental device for researching the shield tunnel segment performance degradation mechanism further comprises two hydraulic driving pieces 6, the two hydraulic driving pieces 6 are respectively arranged at two ends of the arc segment 100, the hydraulic driving pieces 6 are fixed with the base 1, and the output end of the hydraulic driving pieces is abutted against the arc segment 100.
In the embodiment shown in fig. 1, the left end of the arc segment 100 is hinged to the bracket 12, the bottom end of the arc segment 100 is slidably connected to the slide rail 11, the hydraulic driving part 6 is disposed on the base 1 and located at the right end of the arc segment 100, and during an experiment, the hydraulic driving part 6 can be supported at the end of the arc segment 100 to provide a fixing acting force of the arc segment 100, so as to provide an initial environment for the arc segment 100. The direction of the force is fixed and parallel to the slide rail 11. The hydraulic driving part 6 can adopt a hydraulic jack, an electrohydraulic servo control loading system (JAW-2000H) or an oil cylinder. In some embodiments, the hydraulic driving member 6 may be disposed at both ends of the arc segment 100 to fix the arc segment 100.
Optionally, the cover plate 2 and the bracket 12 are connected through a plurality of telescopic rods 22, and the plurality of telescopic rods 22 can drive the cover plate 2 to lift under the drive of the cover plate driving piece 23.
As shown in fig. 1, four telescopic rods 22 are symmetrically arranged at the top end of the cover plate 2, and the telescopic rods 22 can be telescopic in the vertical direction to adjust the distance between the cover plate 2 and the arc-shaped duct piece 100. The top of apron 2 is connected to the bottom of telescopic link 22, and apron driving piece 23 is connected on the top of telescopic link 22, and hydraulic cylinder can be selected to apron driving piece 23, and apron driving piece 23 is fixed on support 12 for the lift of drive telescopic link 22 drive apron 2.
Optionally, the pressing head 31 includes at least two pressing rods parallel to each other, and the at least two pressing rods are disposed along the width direction of the arc-shaped segment 100 and symmetrically disposed on the convex arc of the arc-shaped segment 100.
As shown in fig. 1, the arc segment 100 is in a width direction perpendicular to the paper surface, and at least two compression rods are symmetrically arranged on the left and right sides of the arc segment 100, and are used for applying simulated soil pressure to the arc segment 100 in an experiment, and the lengths of the two compression rods are equal along the width direction of the arc segment 100, so that uniform soil pressure simulation can be provided for the arc segment 100. The pressing head 31 is disposed at the top end of the cover plate 2 from top to bottom, so that attention should be paid to sealing at the joint of the pressing head 31 and the cover plate 2 during installation, so as to ensure the sealing performance of the pressurizing bin 21.
Optionally, the experimental device for researching the shield tunnel segment performance degradation mechanism further comprises an image acquisition device, a steel bar corrosion degree detector, an acoustic emission sensor and a strain gauge, wherein the image acquisition device is at least two, the image acquisition device is respectively arranged on the side face and the bottom face of the arc segment 100, a probe of the steel bar corrosion degree detector is connected to the stressed main rib of the arc segment 100, and the acoustic emission sensor and the strain gauge are respectively arranged on the concave arc surface of the arc segment 100.
The image acquisition device generally adopts a CCD camera and is used for acquiring images of the side surface and the concave arc surface of the arc-shaped duct piece 100, and the images comprise images of crack initiation and expansion rules and the like of the outer crack of the arc-shaped duct piece 100, and the image acquisition device can be provided with ion imaging velocimetry technology analysis software GeoPIV to measure and record real-time displacement of the arc-shaped duct piece 100 so as to analyze and calculate stress deformation, displacement and other information of the arc-shaped duct piece 100 according to the images after a test. For arc segment 100 at different erosion times, the acoustic emission sensor is used to monitor the damage level inside the concrete in real time, and an acoustic emission detection system (DS 5-16C) is used to detect, in some embodiments, the probe of the acoustic emission sensor may be disposed on the bottom side of the stainless steel mesh. The strain gage may detect mechanical deformation of the surface of the arcuate segment 100. The steel bar corrosion degree detector is used for detecting the corrosion amount of the stressed main rib in the arc-shaped duct piece 100.
Optionally, the experimental device for researching the shield tunnel segment performance degradation mechanism further comprises a chloride ion concentration measuring instrument, and a probe of the chloride ion concentration measuring instrument is arranged in the pressurizing bin 21 and used for detecting the concentration of chloride ions in the pressurizing bin 21.
It will be appreciated that during the test, a portion of the sodium chloride solution will react with the arcuate segment 100 to reduce the chloride ion concentration, and that in order to more truly simulate a real erosion environment, it is necessary to supplement chloride ions. Specifically, according to the detection result of the chloride ion concentration meter, when the chloride ion concentration is lowered, chloride ions are added into the pressurizing chamber 21 through the feed port on the cover plate 2 to maintain the chloride ion concentration unchanged.
Optionally, the experimental device for researching the shield tunnel segment performance degradation mechanism further comprises a booster pump, and the booster pump is arranged on the water delivery pipe 41 to pressurize the sodium chloride solution and deliver the sodium chloride solution to the pressurizing bin 21.
It will be appreciated that the pressurized compartment 21 is in a simulated high water pressure environment and therefore the sodium chloride solution in the water tank 4 needs to be injected into the pressurized compartment 21 by means of a booster pump. Conventionally, a check valve and a regulating valve are provided on the water pipe 41 to control the flow rate of the sodium chloride solution.
According to the experimental device for researching the shield tunnel segment performance degradation mechanism provided by the invention, the invention also provides an experimental method for researching the shield tunnel segment performance degradation mechanism, as shown in a flow chart shown in fig. 3, comprising the following steps:
s1, connecting an electrified wire with a stressed main rib of an arc-shaped duct piece 100 and extending out of the arc-shaped duct piece 100 to be connected with the positive electrode of a constant current instrument 5 to form an anode, and arranging a stainless steel wire mesh in a target corrosion area in a pressurizing bin 21 and connecting the stainless steel wire mesh with the negative electrode of the constant current instrument 5 to form a cathode;
as shown in fig. 2, a stainless steel wire mesh is arranged on the convex arc surface of the arc-shaped duct piece 100 in the pressurizing bin 21, the stainless steel wire mesh is communicated with sodium chloride solution, the stainless steel wire mesh completely covers the target corrosion area of the convex arc surface of the arc-shaped duct piece 100, and the negative electrode of the constant current meter 5 (model PS-1) is connected with the stainless steel wire mesh through a wire. The current of the constant current meter 5 is adjusted, so that different corrosion conditions of the arc-shaped duct piece 100 can be simulated and detected.
S2, prefabricating initial cracks at the convex arc top and the hoisting hole of the arc-shaped duct piece 100, arranging an acoustic emission sensor probe and a strain gauge on the concave arc surface of the arc-shaped duct piece 100, and arranging an image acquisition device on the side surface of the arc-shaped duct piece 100 and below the concave arc respectively;
the device can be additionally arranged or reasonably selected according to experimental test purposes and test requirements, the number of the acoustic emission sensors and the strain gauges is not limited, and the strain gauges are arranged at the initial crack positions so as to obtain the deformation characteristics of the crack. The acoustic emission sensors test defects of the concrete structure on the arc segment 100, and a plurality of acoustic emission sensors may be arranged according to experimental experience so as to obtain real-time test data. The initial cracks are generally arranged at the back, the hoisting holes and the like on the arc-shaped duct piece 100, and the cracks or grooves with different sizes and depths are prefabricated by a small stone sawing machine. The image acquisition device can shoot the side and bottom images of the arc segment 100, preferably adopts a high-definition CCD camera, and can record a plurality of images of crack initiation and extension rules and the like of corresponding parts on the arc segment 100.
S3, the soil pressure loading assembly 3 pressurizes the convex arc surface of the arc-shaped duct piece 100;
the soil pressure loading assembly 3 calculates and simulates the bending moment of the arc-shaped duct piece 100 under the action of the soil pressure according to the selected working condition, namely the axial force at the two ends, and drives the pressure head 31 to press the convex arc surface of the arc-shaped duct piece 100 through the soil pressure driving piece 32 so as to load.
S4, after the arc-shaped duct piece 100 is stable, covering the cover plate 2 on the convex arc surface of the arc-shaped duct piece 100 and sealing to form a pressurizing bin 21, then injecting sodium chloride solution into the pressurizing bin 21 at high pressure, and recording initial deformation data and initial crack data of the arc-shaped duct piece 100;
s5, starting a constant current meter 5, controlling the current, and simulating the process of bearing high water pressure and chloride ion corrosion of the arc-shaped duct piece 100;
in the test process, the concentration of chloride ions can be monitored in real time by adopting a chloride ion concentration detector (JH-PXS-CL type) and the concentration of the chloride ions can be controlled. In this embodiment, the concentration of the sodium chloride solution is 5% by mass, and the sodium chloride solution needs to be replenished in time when the concentration of chloride ions in the pressurized bin 21 is reduced. According to different erosion test time, the acoustic emission sensor can monitor the damage degree of the inside of the concrete in real time, and the corrosion amount of the stressed main rib inside the arc-shaped duct piece 100 can be intelligently read by adopting the steel bar corrosion degree detector (R62 in China), so that the data required by the experiment are obtained.
S6, performing a bending resistance test on the rusted arc-shaped duct piece 100 to obtain the residual bearing capacity of the arc-shaped duct piece 100.
The arc-shaped pipe piece 100 subjected to corrosion is subjected to performance degradation after corrosion, the arc-shaped pipe piece 100 is dismantled, and a grading loading mode is adopted, so that each grade of load is kept loaded for 5min by referring to a bending resistance test in the specification of prefabricated concrete lining pipe pieces (GB/T22082-2017). During loading, the displacement, crack expansion and maximum crack width of each measuring point on the arc-shaped segment 100 should be recorded. And finally, loading until the indication number of the vertical pressure sensor is not increased any more, and ending the bending resistance test, thereby obtaining the residual bearing capacity of the arc-shaped duct piece 100 after performance degradation.
The experimental device and the method for researching the shield tunnel segment performance degradation mechanism can be used for developing shield tunnel segment concrete test piece test researches under different mechanical fields, chemical fields and combined working conditions according to the test requirements, can be used for researching the deformation and strength corrosion of the segment concrete by the corrosion solution, and can also be used for researching the mechanism of concrete damage under the mechanical-permeation-chemical coupling effect.
According to the experimental method for researching the shield tunnel segment performance degradation mechanism, the accelerated corrosion test of the arc segment 100 is carried out in the environment where the arc segment 100 is subjected to soil pressure, high water pressure and ion erosion, and the residual bearing capacity of the arc segment 100 is measured after the test, so that the shield tunnel segment performance degradation mechanism and the stress performance evolution rule of the shield tunnel lining structure in the service period can be researched.
It is to be understood that the above examples of the present invention are provided for clarity of illustration only and are not limiting of the embodiments of the present invention. Various obvious changes, rearrangements and substitutions can be made by those skilled in the art without departing from the scope of the invention. It is not necessary here nor is it exhaustive of all embodiments. Any modification, equivalent replacement, improvement, etc. which come within the spirit and principles of the invention are desired to be protected by the following claims.
Claims (4)
1. The experimental method for the shield tunnel segment performance degradation mechanism research is characterized by comprising the following steps of:
s1, connecting an electrified wire with a stressed main rib of an arc-shaped duct piece (100) and extending to the outside of the arc-shaped duct piece (100) to be connected with the positive electrode of a constant current meter (5) to form an anode, and arranging a stainless steel wire mesh in a target corrosion area in a pressurizing bin (21) and connecting the stainless steel wire mesh with the negative electrode of the constant current meter (5) to form a cathode;
s2, prefabricating initial cracks at the convex arc top and the hoisting hole of the arc-shaped duct piece (100), arranging an acoustic emission sensor probe and a strain gauge on the concave arc surface of the arc-shaped duct piece (100), and arranging an image acquisition device on the side surface of the arc-shaped duct piece (100) and below the concave arc respectively;
s3, pressurizing the convex arc surface of the arc-shaped duct piece (100) by the soil pressure loading assembly (3);
s4, after the arc-shaped duct piece (100) is stable, a cover plate (2) is covered on the convex arc surface of the arc-shaped duct piece (100) and sealed to form a pressurizing bin (21), then sodium chloride solution is injected into the pressurizing bin (21) at high pressure, and initial deformation data and initial crack data of the arc-shaped duct piece (100) are recorded;
s5, starting the constant current instrument (5) and controlling the current to simulate the process that the arc-shaped duct piece (100) bears high water pressure and chloride ions; monitoring the concentration of the chloride ions in the erosion process, and controlling the mass percentage concentration of the chloride ions to be 5%;
s6, performing a bending resistance test on the corroded arc-shaped duct piece (100) to obtain the residual bearing capacity of the arc-shaped duct piece (100);
the experimental device for be used for shield tunnel section of jurisdiction performance degradation mechanism research includes:
the base (1), be equipped with slide rail (11) and support (12) on base (1), arc section of jurisdiction (100) concave arc is down located on slide rail (11), one end with slide rail (11) articulated, the other end sliding connection slide rail (11);
the cover plate (2) is of a shell structure with one end open, the cover plate (2) is movably connected to the bracket (12), and the open end of the cover plate (2) is covered on one side of a convex arc of the arc-shaped duct piece (100) and is sealed with the surface of the convex arc to form the pressurizing bin (21); the cover plate (2) is connected with the bracket (12) through a plurality of telescopic rods (22), and the telescopic rods (22) can drive the cover plate (2) to lift under the drive of a cover plate driving piece (23);
the soil pressure loading assembly (3), the soil pressure loading assembly (3) comprises a pressure head (31) and a soil pressure driving piece (32), the soil pressure driving piece (32) is arranged on the bracket (12), the output end of the soil pressure driving piece (32) is connected with the pressure head (31), and the pressure head (31) is arranged in the pressure bin (21) and is contacted with the convex arc surface of the arc-shaped duct piece (100) to load simulated soil pressure; the pressure head (31) comprises at least two mutually parallel pressure rods, and at least two pressure rods are arranged along the width direction of the arc-shaped duct piece (100) and symmetrically arranged on the convex arc of the arc-shaped duct piece (100);
the water tank (4) is internally provided with sodium chloride solution, and the water tank (4) is communicated with the pressurizing bin (21) through a water pipe (41);
the positive electrode of the constant current instrument (5) is connected with the stressed main rib of the arc-shaped duct piece (100), and the negative electrode of the constant current instrument (5) is arranged in the pressurizing bin (21);
the probe of the chloride ion concentration tester is arranged in the pressurizing bin (21) and used for detecting the concentration of chloride ions in the pressurizing bin (21);
still include image acquisition device, reinforcing bar corrosion degree detector, acoustic emission sensor and foil gage, image acquisition device is equipped with two at least, locates respectively the side and the bottom surface of arc section of jurisdiction (100), the probe of reinforcing bar corrosion degree detector connect in the atress owner muscle of arc section of jurisdiction (100), acoustic emission sensor with the foil gage is all located arc section of jurisdiction (100) concave arc surface.
2. The experimental method for the study of the degradation mechanism of the performance of the shield tunnel segment according to claim 1, wherein the experimental device for the study of the degradation mechanism of the performance of the shield tunnel segment further comprises a rubber ring which is circumferentially arranged around the open end of the cover plate (2) and can be in sealing contact with the convex arc surface of the arc segment (100) to form the pressurizing bin (21).
3. The experimental method for researching the shield tunnel segment performance degradation mechanism according to claim 1, wherein the experimental device for researching the shield tunnel segment performance degradation mechanism further comprises a hydraulic driving piece (6), the hydraulic driving piece (6) is arranged at the end part of the arc segment (100) and the output end of the hydraulic driving piece (6) is abutted against the arc segment (100), and the hydraulic driving piece (6) is fixed on the base (1).
4. The experimental method for the shield tunnel segment performance degradation mechanism research according to claim 1, wherein the experimental device for the shield tunnel segment performance degradation mechanism research further comprises a booster pump, and the booster pump is arranged on the water pipe (41) to pressurize the sodium chloride solution and convey the sodium chloride solution to the pressurizing bin (21).
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| CN117347252A (en) * | 2023-10-09 | 2024-01-05 | 中交三航(南通)海洋工程有限公司 | Corrosion-resistant degradation test device for shield tunnel segment |
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| CN105403366A (en) * | 2015-09-23 | 2016-03-16 | 同济大学 | Anti-permeability performance test system for shield tunnel segment circumferential seams |
| CN110243677A (en) * | 2019-05-22 | 2019-09-17 | 同济大学 | Shield duct piece steel bar corrosion causes the test method of Stiffness Deterioration under a kind of multifactor effect |
| CN112595533A (en) * | 2020-11-25 | 2021-04-02 | 山东大学 | Shield tunnel stratum action simulation test device and test method thereof |
| CN112763400A (en) * | 2020-12-31 | 2021-05-07 | 中铁第四勘察设计院集团有限公司 | Accelerated corrosion degradation test device for bearing shield tunnel segment under high water pressure effect |
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| CN105403366A (en) * | 2015-09-23 | 2016-03-16 | 同济大学 | Anti-permeability performance test system for shield tunnel segment circumferential seams |
| CN110243677A (en) * | 2019-05-22 | 2019-09-17 | 同济大学 | Shield duct piece steel bar corrosion causes the test method of Stiffness Deterioration under a kind of multifactor effect |
| CN112595533A (en) * | 2020-11-25 | 2021-04-02 | 山东大学 | Shield tunnel stratum action simulation test device and test method thereof |
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