CN111707511B - Method for manufacturing preset crack tunnel segment for joint mechanical test - Google Patents
Method for manufacturing preset crack tunnel segment for joint mechanical test Download PDFInfo
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- CN111707511B CN111707511B CN202010518042.XA CN202010518042A CN111707511B CN 111707511 B CN111707511 B CN 111707511B CN 202010518042 A CN202010518042 A CN 202010518042A CN 111707511 B CN111707511 B CN 111707511B
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N1/00—Sampling; Preparing specimens for investigation
- G01N1/28—Preparing specimens for investigation including physical details of (bio-)chemical methods covered elsewhere, e.g. G01N33/50, C12Q
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N1/00—Sampling; Preparing specimens for investigation
- G01N1/28—Preparing specimens for investigation including physical details of (bio-)chemical methods covered elsewhere, e.g. G01N33/50, C12Q
- G01N1/286—Preparing specimens for investigation including physical details of (bio-)chemical methods covered elsewhere, e.g. G01N33/50, C12Q involving mechanical work, e.g. chopping, disintegrating, compacting, homogenising
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N1/00—Sampling; Preparing specimens for investigation
- G01N1/28—Preparing specimens for investigation including physical details of (bio-)chemical methods covered elsewhere, e.g. G01N33/50, C12Q
- G01N1/36—Embedding or analogous mounting of samples
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N1/00—Sampling; Preparing specimens for investigation
- G01N1/28—Preparing specimens for investigation including physical details of (bio-)chemical methods covered elsewhere, e.g. G01N33/50, C12Q
- G01N1/286—Preparing specimens for investigation including physical details of (bio-)chemical methods covered elsewhere, e.g. G01N33/50, C12Q involving mechanical work, e.g. chopping, disintegrating, compacting, homogenising
- G01N2001/2873—Cutting or cleaving
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Abstract
The invention relates to a method for manufacturing a preset cracked tunnel segment for a joint mechanical test, which comprises the following steps of: 1) determining parameters of the position, angle, length and width of the crack of the tunnel segment joint according to the test scheme; 2) binding segment steel bars, placing the segment steel bars into a segment casting mold, performing preset cracked segment casting, and setting segment structure cracking; 3) cutting segments, and assembling to form segment joint test pieces meeting the requirements of the test scheme; 4) compared with the prior art, the method has the advantages of simple manufacture, convenient operation, no damage to the segment structural steel bars, capability of obtaining the cracks with different interface parameters by adjusting the pouring process, capability of providing reference for the research of the related field and the like.
Description
Technical Field
The invention relates to the field of tunnel cracked segment joint tests, in particular to a method for manufacturing a preset cracked tunnel segment for a joint mechanical test.
Background
The shield tunnel segment joint is a weak part of a tunnel structure, and under the action of various loads in a tunnel construction period and an operation period, the segment joint is usually cracked and damaged, so that the rigidity of the tunnel segment joint is further damaged. Along with the continuous development of segment prefabrication and tunnel construction technology, the segment structure is not only used for a shield tunnel, but also the two linings of the drilling and blasting method tunnel can adopt the prefabricated segment structure more and more in the near future. When the tunnel structure disease is evaluated, the reasonable determination of the rigidity of the cracked duct piece joint is related to the accuracy of the evaluation of the tunnel structure disease, the research on the rigidity of the duct piece joint is generally carried out on duct pieces in a good state at present, the research on the rigidity of the duct piece joint with initial cracking is less, and an effective method for manufacturing a preset cracked duct piece does not exist.
According to the investigation of the crack loss of the tunnel segment joint, the segment crack loss at the joint is mainly caused by the compression shear damage of concrete on the inner side and the outer side of the longitudinal joint, the segment body can not be cracked due to the structural stress in the operation period generally, the common prefabrication method of the cracked segment adopts a mode that the complete segment performs grooving at the corresponding position, the stress steel bar can be damaged due to the overlarge grooving depth, the grooving depth is too small, the grooving is only performed on a protective layer, the situation of the segment joint damage can not be reasonably reproduced, and the preset cracked segment which can be used for accurately describing the stress damage of the segment joint does not have an effective manufacturing method.
Disclosure of Invention
The invention aims to overcome the defects in the prior art and provide a method for manufacturing a preset cracked tunnel segment for a joint mechanical test.
The purpose of the invention can be realized by the following technical scheme:
1. a method for manufacturing a preset cracked tunnel segment for a joint mechanical test is characterized by comprising the following steps:
1) determining parameters of the position, angle, length and width of the crack of the tunnel segment joint according to the test scheme;
2) binding segment steel bars, placing the segment steel bars into a segment casting mold, performing preset cracked segment casting, and setting segment structure cracking;
3) cutting segments, and assembling to form segment joint test pieces meeting the requirements of the test scheme;
4) and (4) putting the segment joint test piece with the prefabricated crack in place on test loading equipment, and carrying out the preset cracked segment joint multi-working-condition test.
In the step 2), the pouring of the preset damaged segment is specifically as follows:
the segment steel reinforcement cage is placed at first, concrete begins to be poured, when the segment steel reinforcement cage is poured to a preset crack position, the concrete pouring is stopped, and segment structure cracks are arranged in a manner of reserving construction cold joints.
And the construction cold joint is correspondingly processed according to the characteristics of the cracked concrete, and the cracked concrete is characterized by the bonding condition of the concrete on two sides of the cracked surface.
The treatment mode of the cold seam is different according to the test requirements of different crack surface adhesion degrees.
When the test requirement is to be used for researching the conditions that the duct piece has initial crack, the crack width is less than 0.2mm and the crack is slight, the adopted cold crack treatment mode is as follows:
and (5) pouring is suspended after the preset crack surface is poured, and pouring is continued after the concrete is initially set.
When the test requirement is to research that the duct piece has obvious crack loss, the crack width is more than 0.2mm but the occlusion force among the concrete coarse aggregates is not lost, the adopted cold crack treatment mode is specifically as follows:
and (5) pouring is suspended after the concrete is poured to the preset crack surface, and pouring is continued after the concrete is finally set.
When the test requirement is for being used for studying that the section of jurisdiction has appeared concrete pressure shear destruction, thick aggregate shearing dislocation promptly, still have atress reinforcing bar and construction reinforcing bar to link to each other, the processing mode of the cold joint of taking specifically is:
and (5) stopping pouring after pouring to a preset crack surface, leveling the concrete surface, and continuing pouring after the concrete is finally set.
After the concrete surface is leveled, a plastic film, a thin plastic plate, a wood plate, a fiber plate or a steel plate is adopted for covering so as to reduce the cohesive force between the front and the back poured concretes, and the cohesive force of the concretes at the two sides of the cold joint is completely eliminated by continuously pouring after final setting, so that the condition that concrete fracturing in actual engineering is reproduced and the reinforcing steel bars still play a part of connecting role is realized.
In the step 4), the segment joint test piece with the prefabricated crack comprises a segment joint test piece with initial crack under the condition of negative bending moment and a segment joint test piece with initial crack under the condition of positive bending moment.
The segment steel reinforcement cage is kept complete and used for reproducing the condition that the segment steel reinforcement cage is not damaged and concrete cracks in actual engineering.
Compared with the prior art, the invention has the following advantages:
firstly, the invention introduces the concrete construction 'cold joint' in the duct piece pouring process, utilizes the reduction of the concrete interface strength parameter caused by the 'cold joint' and simulates the cracking loss of the duct piece joint under the stress condition.
The invention provides a method for leveling an initial setting cold joint, a final setting cold joint and an interface and covering by using a plastic film, which is respectively used for describing the actual conditions of slight crack loss (crack width is less than 0.2mm), obvious crack loss (crack width is more than 0.2mm) but no obvious shearing damage and concrete compression shearing damage (coarse aggregate shearing dislocation) and has comprehensive simulation and good test effect.
The crack prefabrication method provided by the invention is different from a common grooving mode of a cutting machine, can effectively prevent the structural steel bars of the duct piece from being damaged, and has the same working condition as the concrete compression-shear damage in actual engineering.
Drawings
Fig. 1 shows the tunnel segment reinforcement cage in place.
FIG. 2 shows the concrete poured to the predetermined fracture surface.
Fig. 3 shows the completion of segment concreting.
Fig. 4 illustrates the segment cut.
FIG. 5 is a segment joint assembly with a predetermined break.
Fig. 6 is a schematic diagram of setting of the operating conditions, where fig. 6a is a schematic diagram of setting of a normal operating condition with positive bending moment, fig. 6b is a schematic diagram of setting of a crack operating condition with positive bending moment, fig. 6c is a schematic diagram of setting of a normal operating condition with negative bending moment, and fig. 6d is a schematic diagram of setting of a crack operating condition with negative bending moment.
FIG. 7 is a flow chart of the steps of the present invention.
Detailed Description
The invention is described in detail below with reference to the figures and specific embodiments.
Examples
As shown in fig. 7, the invention provides a method for manufacturing a preset cracked tunnel segment for a joint mechanical test, which comprises the following steps as shown in fig. 1-5:
1) detecting tunnel diseases, namely detecting a crack damage mode, crack degree evaluation, crack opening conditions and the like, and determining parameters such as the position, angle, length, width and the like of crack of the segment joint;
2) formulating a cracked segment joint test scheme, and determining a test segment size, segment cutting and segment joint assembling scheme for a cracked segment joint mechanical test by considering the characteristics of test loading equipment;
3) a preset cracked duct piece pouring scheme is formulated, and parameters such as the position, the angle, the length and the width of a cracked duct piece are determined based on duct piece cracking state evaluation;
4) binding segment steel bars, placing the segment steel bars into a segment casting mold, and setting segment structure crack loss by adopting different cold joint treatment modes in the concrete casting process according to segment detection and evaluation conclusions; for different experimental requirements and simulation situations, the following three categories are specifically distinguished:
(1) after the cast is carried out to the preset crack surface, the casting is suspended, and the casting is continued after the initial setting of the concrete (the casting is continued after the initial setting, the cohesiveness of the concrete at two sides of the cold joint is still strong, and the method can be used for researching the condition that the segment has initial crack, the crack width is less than 0.2mm, and the crack loss is very slight);
(2) after the cast is carried out to the preset fracture surface, the casting is suspended, and the casting is continued after the concrete is finally solidified (the casting is continued after the concrete is finally solidified, the cohesiveness of the concrete at two sides of the cold joint is further weakened, the method can be used for researching that the segment is obviously fractured, the width of the crack is more than 0.2mm, but the biting force among the concrete coarse aggregates is still not lost);
(3) and after the concrete is poured to a preset crack surface, the pouring is stopped, the concrete surface is leveled, a plastic film is adopted for covering (or thin plastic plates, wood plates, fiber plates, steel plates and the like are adopted) to reduce the adhesive force between the front and back poured concrete, and the pouring is continued after final setting (the concrete on the two sides of the cold joint has no adhesive property basically, and can be used for researching that the concrete of the duct piece is subjected to compression shear damage and coarse aggregate shearing dislocation, but the stressed reinforcing steel bars are still connected with the constructional reinforcing steel bars).
5) Segment cutting is carried out according to a segment joint mechanical test scheme, and segment joint test pieces meeting the requirements of the test scheme are assembled; as shown in fig. 4.
6) And (4) putting the segment joint with the pre-crack on test loading equipment in place, and carrying out a multi-working-condition test on the segment joint with the pre-crack. As shown in fig. 5.
In the same procedure, a segment test piece having an initial crack in the case of a negative bending moment was obtained, as shown in fig. 6.
Claims (2)
1. A method for manufacturing a preset cracked tunnel segment for a joint mechanical test is characterized by comprising the following steps:
1) determining parameters of the position, angle, length and width of the crack of the tunnel segment joint according to the test scheme;
2) ligature section of jurisdiction reinforcing bar is placed into the section of jurisdiction and is pour the mould, predetermines the segment that splits and decreases and pour, sets up the segment structure and splits and decreases, predetermines the segment that splits and decreases and pour and specifically do:
firstly, placing a segment reinforcement cage, starting to pour concrete, stopping pouring concrete when pouring to a preset crack position, and setting segment structure cracks in a manner of reserving construction cold joints;
the construction cold joint carry out the corresponding processing of cold joint according to the crack face concrete characteristic, the crack face concrete characteristic be the bonding condition of crack face both sides concrete, the processing mode of cold joint is different according to the experimental requirement of different crack face adhesion degrees, specifically includes:
when the test requirement is to be used for researching the conditions that the duct piece has initial crack, the crack width is less than 0.2mm and the crack is slight, the adopted cold crack treatment mode is as follows:
pouring is suspended after the preset crack surface is poured, and pouring is continued after the concrete is initially set;
when the test requirement is to research that the duct piece has obvious crack loss, the crack width is more than 0.2mm but the occlusion force among the concrete coarse aggregates is not lost, the adopted cold crack treatment mode is specifically as follows:
pouring is suspended after the preset crack surface is poured, and pouring is continued after the concrete is finally set;
when the test requirement is for being used for studying that the section of jurisdiction has appeared concrete pressure shear destruction, thick aggregate shearing dislocation promptly, still have atress reinforcing bar and construction reinforcing bar to link to each other, the processing mode of the cold joint of taking specifically is:
pouring is suspended after the concrete is poured to a preset crack surface, and pouring is continued after the concrete surface is leveled and the concrete is finally set;
after the concrete surface is leveled, a plastic film, a thin plastic plate, a wood plate, a fiber plate or a steel plate is adopted for covering so as to reduce the cohesive force between the front and back poured concretes, the cohesive force of the concretes at the two sides of the cold joint is completely eliminated by continuously pouring after final setting, the condition that concrete fracturing in the actual engineering is realized, the reinforcing steel bars still play a part of connecting action is realized, and the segment steel reinforcement cage is kept complete so as to reproduce the condition that the segment steel reinforcement cage in the actual engineering is not damaged and the concrete is cracked;
3) cutting segments, and assembling to form segment joint test pieces meeting the requirements of the test scheme;
4) and (4) putting the segment joint test piece with the prefabricated crack in place on test loading equipment, and carrying out the preset cracked segment joint multi-working-condition test.
2. The method for manufacturing a pre-cracked tunnel segment for joint mechanical test according to claim 1, wherein in the step 4), the segment joint test pieces with pre-cracks comprise segment joint test pieces with initial cracks under negative bending moment and segment joint test pieces with initial cracks under positive bending moment.
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| Application Number | Priority Date | Filing Date | Title |
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| CN202010518042.XA CN111707511B (en) | 2020-06-09 | 2020-06-09 | Method for manufacturing preset crack tunnel segment for joint mechanical test |
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| CN202010518042.XA CN111707511B (en) | 2020-06-09 | 2020-06-09 | Method for manufacturing preset crack tunnel segment for joint mechanical test |
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| CN111707511B true CN111707511B (en) | 2021-07-20 |
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| CN112345186B (en) * | 2020-10-29 | 2022-03-08 | 同济大学 | Train-track-tunnel-soil body coupling vibration test system |
| CN115372170B (en) * | 2022-10-24 | 2023-02-07 | 西南石油大学 | Bending and twisting test device and method for steel-concrete suspension tunnel pipe joint with damaged outer pipe wall |
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| CN101464234B (en) * | 2008-12-31 | 2011-02-09 | 上海市隧道工程轨道交通设计研究院 | Duct test piece production method used for duct piece connector test |
| DE102009003726B3 (en) * | 2009-04-02 | 2010-11-04 | Herold Kunststofftechnik | Betontübbing and method for producing the same |
| CN105181252B (en) * | 2015-09-23 | 2019-01-25 | 同济大学 | Test specimen is used in a kind of test of duct pieces of shield tunnel circumferential weld anti-permeability performance |
| CN111044370A (en) * | 2019-12-19 | 2020-04-21 | 上海市基础工程集团有限公司 | Mechanical property test method for duct piece joint |
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