CN114279947A - 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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- 230000007246 mechanism Effects 0.000 title claims abstract description 48
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- 238000006731 degradation reaction Methods 0.000 title claims abstract description 47
- 238000000034 method Methods 0.000 title claims abstract description 14
- FAPWRFPIFSIZLT-UHFFFAOYSA-M Sodium chloride Chemical compound [Na+].[Cl-] FAPWRFPIFSIZLT-UHFFFAOYSA-M 0.000 claims abstract description 46
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- VEXZGXHMUGYJMC-UHFFFAOYSA-M Chloride anion Chemical compound [Cl-] VEXZGXHMUGYJMC-UHFFFAOYSA-M 0.000 claims description 31
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Abstract
The invention belongs to the technical field of shield tunnel durability tests, and discloses an experimental device and a method for researching a performance degradation mechanism of a shield tunnel segment, wherein the experimental device comprises a base, a cover plate, a soil pressure loading assembly, a water tank and a constant current instrument, a concave arc of an arc-shaped segment is downwards arranged on a slide rail of the base, one end of the arc-shaped segment is hinged with the slide rail, and the other end of the arc-shaped segment is connected with the slide rail in a sliding manner; the cover plate is of a shell structure with an opening at one end, the cover plate is movably connected with the support on the base, and the opening end of the cover plate is covered on the surface of the arc-shaped duct piece and sealed to form a pressurizing bin; the soil pressure loading assembly loads simulated soil pressure to the arc-shaped pipe piece, the water tank provides sodium chloride solution for the pressurizing bin, the anode of the constant current instrument is connected with the stress main rib of the arc-shaped pipe piece, and the cathode 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 subjected to soil pressure, high water pressure and ion erosion, and is convenient for researching the performance degradation mechanism of the duct piece of the shield tunnel and the evolution law of the stress performance of the lining structure of the shield tunnel 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 the surrounding environment, strong adaptability to complex geological conditions, safe and quick construction and the like, and becomes one of the commonly adopted construction methods for tunnels such as urban subways, cross-rivers, cross-sea and the like in China. For the shield tunnel adopting the reinforced concrete segment, the problems of structural corrosion durability under the coupling action of long-time erosion environment and complex structural load are increasingly highlighted, including the phenomena of corrosion of inner-row reinforcing steel bars, exposed parts of connecting bolts and steel pull rods of the tunnel structure, peeling of a concrete protective layer of the segment, leakage at preformed holes and joints of the segment and the like, so that the generated tunnel facility has huge maintenance cost and maintenance cost.
The existing durability research and test mainly comprises modeling and testing the influence of harmful ion erosion in the environment as a main factor, and testing and researching the durability problem of the shield tunnel possibly caused by the lack of the combined action of the loading condition.
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 a shield tunnel segment under the action of chloride ion erosion and high-pressure water coupling and research the shield tunnel segment performance degradation mechanism and the stress performance evolution rule of a shield tunnel lining structure in service period.
In order to achieve the purpose, the invention adopts the following technical scheme:
the invention firstly provides an experimental device for researching the performance degradation mechanism of a shield tunnel segment, which comprises the following components:
the shield tunnel segment mounting device comprises a base, wherein a sliding rail and a support are arranged on the base, a section of arc-shaped segment of a shield tunnel segment is selected, a concave arc of the arc-shaped segment is downwards arranged on the sliding rail, one end of the arc-shaped segment is hinged with the sliding rail, and the other end of the arc-shaped segment is connected with the sliding rail in a sliding manner;
the cover plate is of a shell structure with an opening at one end, the cover plate is movably connected to the support, and the opening end of the cover plate covers 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 pressurizing bin and is in contact with the convex arc surface of the arc-shaped pipe piece to load simulated soil pressure;
the water tank is filled with sodium chloride solution and communicated with the pressurizing bin through a water conveying pipe;
and the anode of the constant current instrument is connected with the stressed main rib of the arc-shaped duct piece, and the cathode 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 arranged around the circumferential direction of the opening end of the cover plate and can be in sealing contact with the convex arc surface of the arc-shaped segment to form the pressurizing bin.
Optionally, the experimental device for researching the performance degradation mechanism of the shield tunnel segment further comprises a hydraulic driving part, the hydraulic driving part is arranged at the end part of the arc-shaped segment, the output end of the hydraulic driving part abuts against the arc-shaped segment, and the hydraulic driving part is fixed on the base.
Optionally, the cover plate is connected with the support through a plurality of telescopic rods, and the telescopic rods can drive the cover plate to lift under the driving of the cover plate driving part.
Optionally, the pressure head includes at least two depression bars that are parallel to each other, at least two the depression bar is followed the width direction setting of arc section of jurisdiction and symmetry setting are in the arc section of jurisdiction on the convex arc.
Optionally, the experimental device for researching the performance degradation mechanism of the shield tunnel segment further comprises at least two image acquisition devices, two steel bar corrosion degree detectors, an acoustic emission sensor and a strain gauge, the two image acquisition devices are respectively arranged on the side surface and the bottom surface of the arc-shaped segment, a probe of each steel bar corrosion degree detector is connected to a stressed main rib of the arc-shaped segment, and the acoustic emission sensor and the strain gauge are both arranged on the concave arc surface of the arc-shaped segment.
Optionally, the experimental apparatus for researching the performance degradation mechanism of the shield tunnel segment further comprises a chloride ion concentration tester, and a probe of the chloride ion concentration tester is arranged in the pressurizing bin and used for detecting the concentration of chloride ions in the pressurizing bin.
Optionally, the experimental apparatus for researching the performance degradation mechanism of the shield tunnel segment further comprises a booster pump, and the booster pump is arranged on the water conveying 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 performance degradation mechanism of the shield tunnel segment provided by the invention, the invention also provides an experimental method for researching the performance degradation mechanism of the shield tunnel segment, which comprises the following steps:
s1, connecting a power-on lead with a stressed main rib of the arc-shaped pipe piece, extending the power-on lead to the outside of the arc-shaped pipe piece to be connected with the anode of a constant current instrument to form an anode, and arranging a stainless steel wire mesh in a target corrosion area in the pressurizing bin and connecting the stainless steel wire mesh with the cathode of the constant current instrument to form a cathode;
s2, prefabricating initial cracks at the top of a convex arc and at a lifting hole of the arc-shaped duct piece, arranging an acoustic emission sensor probe and a strain gauge on the surface of a concave arc 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, pressing the convex arc surface of the arc-shaped pipe piece by the soil pressure loading assembly;
s4, after the arc-shaped duct piece is stabilized, covering a cover plate on the convex arc surface of the arc-shaped duct piece and sealing to form a pressurizing bin, then injecting a sodium chloride solution into the pressurizing bin at high pressure, and recording initial deformation data and initial crack data of the arc-shaped duct piece;
s5, starting the constant current instrument, controlling the current and simulating the arc-shaped pipe piece to bear the high water pressure and the erosion process of chloride ions;
s6, carrying out a bending resistance test on the corroded arc-shaped duct piece to obtain the residual bearing capacity of the arc-shaped duct piece.
Optionally, the 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 performance degradation mechanism of the shield tunnel segment, the soil pressure environment borne by the shield tunnel segment can be simulated by arranging the soil pressure loading assembly, the high water pressure environment borne by the shield tunnel segment can be simulated by arranging the water tank to inject the sodium chloride solution into the pressurizing bin, and the chloride ion erosion environment borne by the shield tunnel segment can be simulated by arranging the constant current instrument, so that the experimental device provided by the invention can realize the durability test of the shield tunnel segment under the coupling action of chloride ion erosion and high-pressure water, and is convenient for researching the performance degradation mechanism of the shield tunnel segment and the stress performance evolution rule of the shield tunnel lining structure in service period.
According to the experimental method for researching the performance degradation mechanism of the shield tunnel segment, the accelerated corrosion test of the arc segment is carried out in the environment that the arc segment is subjected to soil pressure, high water pressure and ion erosion, and the residual bearing capacity of the arc segment is measured after the test, so that the performance degradation mechanism of the shield tunnel segment 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 overall structure diagram of an experimental device for researching shield tunnel segment performance degradation mechanism provided by the invention;
FIG. 2 is a schematic connection diagram of a constant current instrument and an arc-shaped segment in an experimental device for researching a degradation mechanism of shield tunnel segment performance provided by the invention;
fig. 3 is a flowchart of an experimental method for researching a shield tunnel segment performance degradation mechanism provided by the invention.
In the figure:
100. an arc-shaped duct piece;
1. a base; 11. a slide rail; 12. a support;
2. a cover plate; 21. a pressurizing bin; 22. a telescopic rod; 23. a cover plate driving member;
3. an earth pressure loading assembly; 31. a pressure head; 32. a soil pressure driving member; 4. a water tank; 41. a water delivery pipe; 5. a constant current meter; 6. a hydraulic drive.
Detailed Description
The present invention will be described in further detail with reference to the accompanying drawings and examples. It is to be understood that the specific embodiments described herein are merely illustrative of the invention and are not limiting of the invention. It should be further noted that, for the convenience of description, only some of the structures related to the present invention are shown in the drawings, not all of the structures.
In the description of the present invention, unless expressly stated or limited otherwise, the terms "connected," "connected," and "fixed" are to be construed broadly, e.g., as meaning permanently connected, removably connected, or integral to one another; can be mechanically or electrically connected; either directly or indirectly through intervening media, either internally or in any other relationship. 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 otherwise expressly stated or limited, "above" or "below" a first feature means that the first and second features are in direct contact, or that the first and second features are not in direct contact but are in contact with each other via another feature therebetween. Also, the first feature being "on," "above" and "over" the second feature includes the first feature being directly on and obliquely above the second feature, or merely indicating that the first feature is at a higher level than the second feature. A first feature being "under," "below," and "beneath" a second feature includes the first feature being directly under and obliquely below the second feature, or simply meaning that the first feature is at a lesser elevation than the second feature.
In the description of the present embodiment, the terms "upper", "lower", "left", "right", and the like are used based on the orientations and positional relationships shown in the drawings only for convenience of description and simplification of operation, and do not indicate or imply that the referred device or element must have a specific orientation, be configured and operated in a specific orientation, and thus, should not be construed as limiting the present invention. Furthermore, the terms "first" and "second" are used only for descriptive purposes and are not intended to have a special meaning. The term "plurality" is to 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 action 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 service period.
As shown in fig. 1-2, an experimental device for researching shield tunnel segment performance degradation mechanism comprises a base 1, a cover plate 2, an earth pressure loading assembly 3, a water tank 4 and a constant current instrument 5, wherein the base 1 is provided with a slide rail 11 and a support 12, a section of arc segment 100 of a shield tunnel segment is selected, a concave arc of the arc segment 100 is downwards arranged on the slide rail 11, one end of the arc segment 100 is hinged with the slide rail 11, and the other end of the arc segment 100 is slidably connected with the slide rail 11; the cover plate 2 is of a shell structure with an opening at one end, the cover plate 2 is movably connected to the support 12, and the opening end of the cover plate 2 is covered on one side of the convex arc of the arc-shaped duct piece 100 and 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 support 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 in contact with the convex arc surface of the arc-shaped pipe 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 conveying pipe 41; the positive pole of the constant current instrument 5 is connected with the stressed main rib of the arc-shaped duct piece 100, and the negative pole is arranged in the pressurizing bin 21.
As shown in fig. 1, in this embodiment, a section of arc-shaped segment 100 of a shield tunnel segment is selected, and the arc-shaped segment 100 is obtained by pouring a stressed main rib with concrete. The section department in both ends is equipped with articulated seat, articulates on base 1, specifically can articulate on slide rail 11 or on support 12 with fixed displacement, the other end of arc section of jurisdiction 100 can with slide rail 11 between the relative slip, can obtain the deformation and the displacement of arc section of jurisdiction 100 under simulation soil pressure when the protruding arc surface of arc section of jurisdiction 100 is exerted and is simulated soil pressure. The cover plate 2 has the same radian as the arc-shaped duct piece 100 for the opening end so as to completely cover and seal the space between the two, during 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 end opposite to the opening end is contacted with the outer wall of the convex arc top end of the arc-shaped duct piece 100 so as to crimp the arc-shaped duct piece 100. The sodium chloride solution stored in the water tank 4 is filled into the pressurizing bin 21 to simulate the high-water-pressure environment of the shield tunnel segment, and the specific pressure value can be set according to the experimental working condition.
According to the experimental device for researching the performance degradation mechanism of the shield tunnel segment, the earth pressure environment borne by the shield tunnel segment can be simulated by arranging the earth pressure loading assembly 3, the high water pressure environment borne by the shield tunnel segment can be simulated by arranging the water tank 4 and injecting the sodium chloride solution into the pressurizing bin 21, and the chloride ion erosion environment borne by the shield tunnel segment can be simulated by arranging the constant current instrument 5.
Optionally, the experimental apparatus for researching the performance degradation mechanism of the shield tunnel segment further includes a rubber ring, the rubber ring is disposed around the circumference of 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 chamber 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 prevent the sodium chloride solution in the pressurizing bin 21 from leaking to cause pressure release and influence the test precision. The rubber ring is an elastic part, 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 performance degradation mechanism of the shield tunnel segment further comprises two hydraulic driving parts 6, the two hydraulic driving parts 6 are respectively arranged at two ends of the arc-shaped segment 100, the hydraulic driving parts 6 are fixed on the base 1, and the output end of the hydraulic driving part abuts against the arc-shaped segment 100.
In the embodiment shown in fig. 1, the left end of the arc-shaped duct piece 100 is hinged to the support 12, the bottom end is slidably connected to the slide rail 11, the hydraulic driving member 6 is disposed on the base 1 and located at the right end of the arc-shaped duct piece 100, and during the experiment, the hydraulic driving member 6 can support the end of the arc-shaped duct piece 100 to provide the fixing acting force of the arc-shaped duct piece 100, so as to provide the initial environment for the arc-shaped duct piece 100. The fixing force is directed parallel to the slide rail 11. The hydraulic driving piece 6 can adopt a hydraulic jack, an electro-hydraulic servo control loading system (JAW-2000H) or a cylinder. In some embodiments, hydraulic actuators 6 may be provided at each end of segment 100 to secure segment 100.
Optionally, the cover plate 2 and the bracket 12 are connected by a plurality of telescopic rods 22, and the plurality of telescopic rods 22 can drive the cover plate 2 to lift under the driving of the cover plate driving member 23.
As shown in fig. 1, four telescopic rods 22 are symmetrically disposed at the top end of the cover plate 2, and the telescopic rods 22 can be extended and retracted 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 drive telescopic link 22 drives the lift of 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 duct piece 100 and symmetrically disposed on the convex arc of the arc-shaped duct piece 100.
As shown in fig. 1, the arc-shaped duct piece 100 is in the width direction perpendicular to the paper surface, and at least two compression bars are arranged on the left and right sides of the arc-shaped duct piece 100 in a bilateral symmetry manner, so as to apply simulated soil pressure to the arc-shaped duct piece 100 during an experiment, wherein the two compression bars are equal in length along the width direction of the arc-shaped duct piece 100, and can provide uniform soil pressure simulation for the arc-shaped duct piece 100. It should be noted that, the indenter 31 is inserted into the top end of the cover plate 2 from top to bottom, so that attention should be paid to the sealing at the joint of the indenter 31 and the cover plate 2 during installation to ensure the sealing performance of the pressurized container 21.
Optionally, the experimental device for the research on the degradation mechanism of the shield tunnel segment performance further comprises at least two image acquisition devices, two steel bar corrosion degree detectors, two acoustic emission sensors and two strain gauges, the two image acquisition devices are respectively arranged on the side surface and the bottom surface of the arc-shaped segment 100, the probe of each steel bar corrosion degree detector is connected to the stressed main rib of the arc-shaped segment 100, and the acoustic emission sensors and the strain gauges are both arranged on the concave arc surface of the arc-shaped 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, including images of crack initiation and expansion rules and the like outside the arc-shaped duct piece 100, and the image acquisition device can be provided with GeoPIV (GeoPIV) analysis software for measuring and recording real-time displacement of the arc-shaped duct piece 100 so as to analyze and calculate information such as stress deformation and displacement of the arc-shaped duct piece 100 according to images after a test. Aiming at the arc-shaped duct pieces 100 under different erosion times, the acoustic emission sensor is used for monitoring the damage degree inside the concrete in real time and detecting the damage degree by adopting an acoustic emission detection system (DS5-16C), and in some embodiments, a probe of the acoustic emission sensor can be arranged on the bottom side of the stainless steel wire mesh. The strain gauge can detect mechanical deformation of the surface of the segment 100. The reinforcing steel bar corrosion degree detector is used for detecting the corrosion amount of the stressed main reinforcing steel bars inside the arc-shaped duct piece 100.
Optionally, the experimental apparatus for researching the performance degradation mechanism of the shield tunnel segment 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 can be understood that, in the test process, a part of the sodium chloride solution will have an erosion reaction with the arc-shaped duct piece 100 to reduce the concentration of the chloride ions, and in order to simulate a real erosion environment more truly, the chloride ions need to be supplemented. Specifically, according to the detection result of the chlorine ion concentration meter, when the chlorine ion concentration is reduced, the chlorine ion is added into the pressurizing chamber 21 through the feed opening of the cover plate 2 to maintain the chlorine ion concentration constant.
Optionally, the experimental apparatus for researching the performance degradation mechanism of the shield tunnel segment 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.
It will be appreciated that the pressurized chamber 21 simulates a high water pressure environment, and therefore, the sodium chloride solution in the water tank 4 needs to be injected into the pressurized chamber 21 by means of a booster pump. Conventionally, a check valve and an adjusting 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 performance degradation mechanism of the shield tunnel segment provided by the invention, the invention also provides an experimental method for researching the performance degradation mechanism of the shield tunnel segment, as shown in a flow chart shown in fig. 3, the experimental method comprises the following steps:
s1, connecting a power-on lead with a stressed main rib of the arc-shaped duct piece 100, extending the power-on lead out of the arc-shaped duct piece 100 to be connected with the anode of the constant current instrument 5 to form an anode, and arranging a stainless steel wire mesh in a target corrosion area in the pressurizing bin 21 and connecting the stainless steel wire mesh with the cathode 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 a sodium chloride solution, the stainless steel wire mesh completely covers a target corrosion area on the convex arc surface of the arc-shaped duct piece 100, and a negative electrode of the constant current instrument 5 (model PS-1) is connected with the stainless steel wire mesh through a wire. The current of the constant current instrument 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 top of a convex arc and at a lifting hole of the arc-shaped pipe piece 100, arranging an acoustic emission sensor probe and a strain gauge on the concave arc surface of the arc-shaped pipe piece 100, and arranging an image acquisition device on the side surface of the arc-shaped pipe piece 100 and below the concave arc respectively;
the device can be increased or reasonably chosen according to the experiment test purpose and the test requirement, the number of the acoustic emission sensors and the strain gauges is not limited, and the common strain gauges are arranged at the positions with the initial cracks so as to obtain the deformation characteristics of the cracks. The acoustic emission sensors are used for testing the defects of the concrete structure on the arc-shaped duct piece 100, and a plurality of acoustic emission sensors can be arranged according to experimental experience so as to obtain real-time test data. The initial cracks are generally arranged on the upper back part, the hoisting holes and the like of the arc-shaped duct piece 100, and cracks or grooves and the like with different sizes and depths are prefabricated by adopting a small stone sawing machine. The image acquisition device can shoot the side and bottom surface image of arc section of jurisdiction 100, and the image acquisition device preferably adopts high definition CCD camera, can record a plurality of images such as crack initiation and the extension law of corresponding part on the arc section of jurisdiction 100.
S3, the soil pressure loading assembly 3 pressurizes the convex arc surface of the arc-shaped pipe piece 100;
the soil pressure loading assembly 3 calculates the bending moment applied to the arc-shaped duct piece 100 under the action of simulated soil pressure, namely the axial force at two ends according to the selected working condition, and drives the pressure head 31 to press the convex arc surface of the arc-shaped duct piece 100 to load through the soil pressure driving part 32.
S4, after the arc-shaped duct piece 100 is stabilized, 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 a 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 the constant current instrument 5 and controlling the current, and simulating the arc-shaped duct piece 100 to bear the high water pressure and the chloride ion erosion process;
in the test process, a chloride ion concentration detector (JH-PXS-CL type) can be used for monitoring the concentration of chloride ions in real time and controlling the concentration of the chloride ions. The mass percent concentration of the sodium chloride solution adopted in the embodiment is 5%, and the sodium chloride solution needs to be supplemented in time when the concentration of the chloride ions in the pressurizing bin 21 is reduced. Aiming at different erosion test time, the internal damage degree of the concrete can be monitored in real time by adopting an acoustic emission sensor, and the corrosion amount of the stressed main rib inside the arc-shaped duct piece 100 can be intelligently read by adopting a steel bar corrosion degree detector (Huashi R62), so that data required by an experiment can be obtained.
And 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.
After the corroded arc-shaped duct piece 100 is corroded, the performance is degraded, the arc-shaped duct piece 100 is dismantled, a graded loading mode is adopted according to a bending resistance test in the specification of precast concrete lining duct piece (GB/T22082-2017), and each grade of load is kept loaded for 5 min. The displacement of each measuring point on the arc-shaped duct piece 100, the crack propagation condition, the maximum crack width and the like should be recorded in the loading process. And finally, loading until the reading of the vertical pressure sensor does not rise any more, and finishing the bending resistance test to obtain the residual bearing capacity of the arc-shaped duct piece 100 with degraded performance.
By applying the experimental device and the method for researching the degradation mechanism of the shield tunnel segment performance, the experimental research on the shield tunnel segment concrete test piece under different mechanical fields, chemical fields and combined working conditions of the mechanical fields and the chemical fields can be developed according to the experimental requirements, and the experimental device and the method can be used for researching the deformation and strength corrosion of the segment concrete caused by erosion solution and the mechanism of concrete damage under the mechanical-permeation-chemical coupling action.
According to the experimental method for researching the performance degradation mechanism of the shield tunnel segment, the accelerated corrosion test of the arc segment 100 is carried out in the environment that 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 performance degradation mechanism of the shield tunnel segment and the stress performance evolution rule of the shield tunnel lining structure in the service period can be researched.
It should be understood that the above-described embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention. Numerous obvious variations, adaptations and substitutions will occur to those skilled in the art without departing from the scope of the invention. And are neither required nor exhaustive of all embodiments. Any modification, equivalent replacement, and improvement made within the spirit and principle of the present invention should be included in the protection scope of the claims of the present invention.
Claims (10)
1. The utility model provides an experimental apparatus for a shield tunnel section of jurisdiction performance degradation mechanism research which characterized in that includes:
the shield tunnel segment assembling device comprises a base (1), wherein a sliding rail (11) and a support (12) are arranged on the base (1), a section of arc-shaped segment (100) of a shield tunnel segment is selected, a concave arc of the arc-shaped segment (100) is downwards arranged on the sliding rail (11), one end of the arc-shaped segment is hinged with the sliding rail (11), and the other end of the arc-shaped segment is connected with the sliding rail (11) in a sliding manner;
the cover plate (2) is of a shell structure with an opening at one end, the cover plate (2) is movably connected to the support (12), and the opening end of the cover plate (2) is covered on one side of a convex arc of the arc-shaped duct piece (100) and 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 support (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 in contact with the convex arc surface of the arc-shaped pipe 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 conveying pipe (41);
the constant current instrument (5), the positive pole of constant current instrument (5) is connected the atress owner muscle of arc section of jurisdiction (100), and the negative pole is located in pressurization storehouse (21).
2. The experimental device for researching the performance degradation mechanism of the shield tunnel segment according to claim 1, further comprising a rubber ring which is arranged around the circumference of the opening end of the cover plate (2) and can be in sealing contact with the convex arc surface of the arc-shaped segment (100) to form the pressurizing bin (21).
3. The experimental device for researching the performance degradation mechanism of the shield tunnel segment according to claim 1, further comprising a hydraulic driving member (6), wherein the hydraulic driving member (6) is arranged at an end portion of the arc-shaped segment (100), an output end of the hydraulic driving member (6) abuts against the arc-shaped segment (100), and the hydraulic driving member (6) is fixed on the base (1).
4. The experimental device for researching the performance degradation mechanism of the shield tunnel segment as claimed in claim 1, wherein the cover plate (2) and the support (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 driving of a cover plate driving member (23).
5. The experimental device for researching the performance degradation mechanism of the shield tunnel segment as claimed in claim 1, wherein the pressing head (31) comprises at least two pressing rods which are parallel to each other, and the at least two pressing rods are arranged along the width direction of the arc-shaped segment (100) and symmetrically arranged on the convex arc of the arc-shaped segment (100).
6. The experimental device for researching the performance degradation mechanism of the shield tunnel segment according to claim 1, further comprising at least two image acquisition devices, at least two steel bar corrosion degree detectors, at least two acoustic emission sensors and at least two strain gauges, wherein the at least two image acquisition devices are respectively arranged on the side surface and the bottom surface of the arc-shaped segment (100), the probe of each steel bar corrosion degree detector is connected to a stressed main rib of the arc-shaped segment (100), and the acoustic emission sensors and the strain gauges are both arranged on the concave arc surface of the arc-shaped segment (100).
7. The experimental device for researching the performance degradation mechanism of the shield tunnel segment according to claim 1, further comprising a chloride ion concentration tester, wherein a probe of the chloride ion concentration tester is arranged in the pressurizing bin (21) and used for detecting the concentration of the chloride ions in the pressurizing bin (21).
8. The experimental device for researching the performance degradation mechanism of the shield tunnel segment according to claim 1, further comprising a booster pump, wherein the booster pump is arranged on the water conveying pipe (41) to pressurize the sodium chloride solution and convey the sodium chloride solution to the pressurizing bin (21).
9. An experimental method for researching a shield tunnel segment performance degradation mechanism is characterized in that the experimental device for researching the shield tunnel segment performance degradation mechanism according to any one of claims 1 to 8 comprises the following steps:
s1, connecting a power-on lead with a stressed main rib of an arc-shaped pipe piece (100), extending the power-on lead to the outside of the arc-shaped pipe piece (100) to be connected with the positive electrode of a constant current instrument (5) to form a positive electrode, 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 negative electrode;
s2, prefabricating initial cracks at the top and the lifting hole of the convex arc 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, pressing the convex arc surface of the arc-shaped pipe piece (100) by the soil pressure loading assembly (3);
s4, after the arc-shaped duct piece (100) is stabilized, covering a 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 a 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 the constant current instrument (5), controlling the current and simulating the erosion process of the arc-shaped duct piece (100) under high water pressure and chloride ions;
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).
10. The experimental method for researching the performance degradation mechanism of the shield tunnel segment of claim 9, wherein the step S5 further comprises a step of monitoring the concentration of the chloride ions, and the concentration of the chloride ions is controlled.
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| CN114813337A (en) * | 2022-04-06 | 2022-07-29 | 北京科技大学 | Stress corrosion test device and method for duct piece under continuous stress |
| 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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