CN111236970A - Shield segment and crack control method thereof - Google Patents
Shield segment and crack control method thereof Download PDFInfo
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- CN111236970A CN111236970A CN202010017415.5A CN202010017415A CN111236970A CN 111236970 A CN111236970 A CN 111236970A CN 202010017415 A CN202010017415 A CN 202010017415A CN 111236970 A CN111236970 A CN 111236970A
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- 238000000034 method Methods 0.000 title claims abstract description 43
- 238000004458 analytical method Methods 0.000 claims abstract description 24
- 238000005452 bending Methods 0.000 claims abstract description 22
- 230000002787 reinforcement Effects 0.000 claims abstract description 14
- 238000010276 construction Methods 0.000 claims description 11
- 239000004519 grease Substances 0.000 claims description 11
- 238000004519 manufacturing process Methods 0.000 claims description 9
- 230000003014 reinforcing effect Effects 0.000 claims description 7
- 230000001360 synchronised effect Effects 0.000 claims description 7
- 230000002457 bidirectional effect Effects 0.000 claims description 5
- 238000011161 development Methods 0.000 claims description 5
- 238000010586 diagram Methods 0.000 description 18
- 238000004364 calculation method Methods 0.000 description 11
- 238000013461 design Methods 0.000 description 7
- 230000000694 effects Effects 0.000 description 6
- 238000004088 simulation Methods 0.000 description 6
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 6
- 239000004567 concrete Substances 0.000 description 4
- 238000009826 distribution Methods 0.000 description 3
- 239000002689 soil Substances 0.000 description 3
- 238000012546 transfer Methods 0.000 description 3
- 229910001294 Reinforcing steel Inorganic materials 0.000 description 2
- 230000002411 adverse Effects 0.000 description 2
- 238000005336 cracking Methods 0.000 description 2
- 230000006378 damage Effects 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 230000000149 penetrating effect Effects 0.000 description 2
- 125000006850 spacer group Chemical group 0.000 description 2
- 230000003068 static effect Effects 0.000 description 2
- 238000005094 computer simulation Methods 0.000 description 1
- 238000012937 correction Methods 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 230000003111 delayed effect Effects 0.000 description 1
- 239000013013 elastic material Substances 0.000 description 1
- 230000002452 interceptive effect Effects 0.000 description 1
- 230000000670 limiting effect Effects 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 230000036961 partial effect Effects 0.000 description 1
- 238000002360 preparation method Methods 0.000 description 1
- 230000002829 reductive effect Effects 0.000 description 1
- 239000011150 reinforced concrete Substances 0.000 description 1
- 238000000926 separation method Methods 0.000 description 1
- 230000006641 stabilisation Effects 0.000 description 1
- 238000011105 stabilization Methods 0.000 description 1
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- E—FIXED CONSTRUCTIONS
- E21—EARTH OR ROCK DRILLING; MINING
- E21D—SHAFTS; TUNNELS; GALLERIES; LARGE UNDERGROUND CHAMBERS
- E21D11/00—Lining tunnels, galleries or other underground cavities, e.g. large underground chambers; Linings therefor; Making such linings in situ, e.g. by assembling
- E21D11/04—Lining with building materials
- E21D11/08—Lining with building materials with preformed concrete slabs
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- E—FIXED CONSTRUCTIONS
- E21—EARTH OR ROCK DRILLING; MINING
- E21D—SHAFTS; TUNNELS; GALLERIES; LARGE UNDERGROUND CHAMBERS
- E21D11/00—Lining tunnels, galleries or other underground cavities, e.g. large underground chambers; Linings therefor; Making such linings in situ, e.g. by assembling
- E21D11/04—Lining with building materials
- E21D11/08—Lining with building materials with preformed concrete slabs
- E21D11/083—Methods or devices for joining adjacent concrete segments
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- E—FIXED CONSTRUCTIONS
- E21—EARTH OR ROCK DRILLING; MINING
- E21D—SHAFTS; TUNNELS; GALLERIES; LARGE UNDERGROUND CHAMBERS
- E21D11/00—Lining tunnels, galleries or other underground cavities, e.g. large underground chambers; Linings therefor; Making such linings in situ, e.g. by assembling
- E21D11/04—Lining with building materials
- E21D11/10—Lining with building materials with concrete cast in situ; Shuttering also lost shutterings, e.g. made of blocks, of metal plates or other equipment adapted therefor
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Abstract
The application discloses a control method for a shield segment crack, which comprises the following steps: analyzing and calculating the load borne by the shield segment by using a first analysis model to obtain the most unfavorable combination of the transverse axial force and the bending moment of the shield segment; determining a contact mode of the circumferential seam parts of the adjacent shield segments; applying the maximum thrust load borne by the shield segment to the shield segment in a second analysis model, introducing the transverse axial force and the bending moment of the worst combination, simulating the contact mode, and analyzing to obtain the transverse and longitudinal internal forces borne by the shield segment; and respectively carrying out reinforcement arrangement on the shield segment envelope according to the internal force of the shield segment in different stages. Still provide a shield structure section of jurisdiction simultaneously. The shield segment and the crack control method thereof can effectively prevent the shield segment from generating cracks.
Description
Technical Field
The application relates to the field of tunnel engineering, in particular to a shield segment and a crack control method thereof.
Background
With the rapid development of the country, the construction of infrastructures such as railways and highways in cities is well developed, and in order to meet the development of a new era, the section area of a tunnel has more and more requirements, along with high standard requirements on the construction process. The reinforced concrete segment is the most common structural member for the shield tunnel, and the safety of the segment structure is an important guarantee for the normal operation of the segment. With the application of the shield method in a large number of tunnel projects in China, the cases of segment cracking and water leakage are increased gradually, and the problems will affect the safety of the projects. In the current tunnel engineering, the problem that partial shield segments generate cracks exists.
Disclosure of Invention
In view of the above, embodiments of the present application are expected to provide a shield segment and a control method for cracks thereof.
In order to achieve the above object, an aspect of the embodiments of the present application provides a method for controlling a crack of a shield segment, including:
analyzing and calculating the load borne by the shield segment by using a first analysis model to obtain the most unfavorable combination of the transverse axial force and the bending moment of the shield segment;
determining a contact mode of the circumferential seam parts of the adjacent shield segments;
applying the maximum thrust load borne by the shield segment to the shield segment in a second analysis model, introducing the transverse axial force and the bending moment of the worst combination, simulating the contact mode, and analyzing to obtain the transverse and longitudinal internal forces borne by the shield segment;
and respectively carrying out reinforcement arrangement on the shield segment envelope according to the internal force of the shield segment in different stages.
Further, the first analysis model is a homogeneous ring model or a beam-spring model.
Further, the load comprises the grease pressure of a grease area, the synchronous grouting pressure of a stripping tail area and the transverse load in the operation period.
Further, the contact manner includes:
the contact mode of the boss comprises that a boss is arranged on one side, located on the thrust load, of the annular seam surface of the shield segment; or the like, or, alternatively,
and the gasket contact mode comprises that a gasket is arranged on one side, deviating from the thrust load, of the annular seam surface of the shield segment.
Further, when the boss contact mode is selected, the shield segment manufacturing precision is less than or equal to 0.3 mm;
when the gasket contact mode is selected, the shield segment manufacturing precision is less than or equal to 0.5 mm.
Further, among the boss contact mode, the boss sets up as the top seal piece the last quantity of shield constructs the section of jurisdiction is 1 ~ 2, sets up as standard block and adjacent piece the last quantity of shield constructs the section of jurisdiction is 2 ~ 4, a plurality of the boss interval sets up.
Furthermore, in the contact mode of the gasket, the distance between the edge of the gasket and the longitudinal seam corner of the shield segment is 5-10 mm; and/or the thickness of the gasket is 3-4 times of the maximum allowable error of the ring width size of the shield segment.
Furthermore, the boss contact mode is that the contact rigidity of the shield segment is calculated according to the geometric and physical characteristics of the shield segment, and a tension-free spring is adopted to simulate the contact between the shield segment and the boss.
Furthermore, the gasket contact mode is that a nonlinear hardening constitutive model is adopted to simulate the nonlinear gasket, and the connection between the gasket and the shield segment is simulated by a tension-free spring.
Further, to shield the tunnel segment envelope carry out the arrangement of reinforcement, include:
reinforcing ribs of the shield segment according to the deep beam requirement;
reinforcing ribs of the shield segments according to bidirectional bias stress; and
when the longitudinal load of the shield segment caused by the uneven annular seam surface is only the construction load, the shield segment is reinforced according to the strength requirement; when the longitudinal load of the shield segment caused by the uneven annular seam surface is a permanent load, the shield segment is reinforced according to the strength requirement and the crack development width requirement.
In another aspect of the embodiments of the present application, there is provided a shield segment manufactured by any one of the above-described control methods.
According to the shield segment and the crack control method thereof, the first analysis model is used for analyzing and calculating the load borne by the shield segment, and the worst combination of the transverse axial force and the bending moment of the shield segment is obtained. Stress conditions of all directions of the shield segments are fully considered, a contact mode of a circular seam part of the adjacent shield segments is determined, and the stress state of the shield segments can be simulated more truly by selecting a proper contact mode. And applying the maximum thrust load borne by the shield segment to the shield segment in a second analytical model, simultaneously leading in the transverse axial force and the bending moment of the worst combination, simulating a contact mode, and analyzing to obtain the transverse and longitudinal internal forces borne by the shield segment. According to the internal force of the shield segment at different stages, the shield segment is respectively reinforced in enveloping manner, the shield strength is pertinently enhanced, and the generation of the shield segment cracks is effectively prevented.
Drawings
FIG. 1 is a structural diagram of a shield segment with cracks in the prior art;
FIG. 2 is a flow chart of shield segment reinforcement calculation in the prior art;
fig. 3 is a flowchart of a method for controlling a shield segment crack in an embodiment of the present application;
FIG. 4 is a schematic diagram of an analytical model of a homogeneous torus model in an embodiment of the present application;
FIG. 5 is a schematic view of an analytical model of a beam-spring model in an embodiment of the present application;
FIG. 6 is a schematic diagram of a simulated structure of shield segment boss contact in an embodiment of the present application;
FIG. 7 is a schematic diagram of a simulated structure of shield segment gasket contact according to an embodiment of the present application;
fig. 8A is a schematic diagram of reinforcing ribs at a circumferential seam surface of a shield segment in an embodiment of the present application;
fig. 8B is a schematic diagram of reinforcing ribs on a circumferential seam surface of a shield segment in an embodiment of the present application;
FIG. 9 is a schematic diagram illustrating a simulation of a shield segment in an embodiment of the present application in which a 2mm thick spacer is disposed to generate cracks;
FIG. 10 is a schematic diagram illustrating a simulation of a shield segment in an embodiment of the present application with a 3mm thick spacer to generate cracks;
FIG. 11 is a schematic view of a shield segment in an embodiment of the present application under longitudinal loading;
FIG. 12 is a schematic diagram of a shield segment boss contact simulation method according to an embodiment of the present application;
FIG. 13 is a schematic diagram of a shield segment gasket contact simulation method according to an embodiment of the present application;
FIG. 14 is a schematic diagram of the lateral loading of the grease zone of the shield segment in an embodiment of the present application;
FIG. 15 is a schematic diagram of the lateral load grouting pressure in the synchronous grouting area of the shield segments in an embodiment of the present application;
fig. 16 is a schematic diagram of static pressure in a lateral load in a synchronous grouting area of shield segments in an embodiment of the present application; and
fig. 17 is a schematic view of lateral loads of a shield segment in an operation period in an embodiment of the present application.
Description of reference numerals:
1. a shield segment; 2. a boss; 3. a gasket; 4. reinforcing steel bars; 5. pad contact; 6. loading; 7. the lug bosses are contacted; 8. cracking; 9. a tenon and a mortise; 10. a ring A; 11. a ring B; 12. a C ring; 13. a spring contact; n, the shield advancing direction; F. thrust load; s, unevenness value; k1, seam return spring; k2, radial shear spring; k3, tangential shear spring.
Detailed Description
It should be noted that, in the present application, technical features in examples and embodiments may be combined with each other without conflict, and the detailed description in the specific embodiment should be understood as an explanation of the gist of the present application and should not be construed as an improper limitation to the present application.
The directional terms used in the description of the present application are intended only to facilitate the description of the application and to simplify the description, and do not indicate or imply that the referenced device or element must have a particular orientation, be constructed and operated in a particular orientation, and thus should not be considered limiting of the application.
Before describing the embodiments of the present application, it is necessary to analyze the cause of the cracks generated in the shield segments in the prior art, and find out the defects of the technical solutions for solving the cracks in the prior art through reasonable analysis, so as to obtain the technical solutions of the embodiments of the present application.
In the prior art, as shown in fig. 1, the direction of a thrust load F is opposite to the shield advancing direction N, and a shield segment 1 is a prefabricated part, so that a size error cannot be avoided, and therefore, an uneven value S exists on a circumferential seam surface of the shield segment 1, and the uneven circumferential seam surface influences the stress of a structure, so that a crack 8 is generated on the shield segment 1.
In the prior art, referring to fig. 2, the stress calculation of the overall structure formed by splicing shield segments 1 is divided into a transverse part and a longitudinal part according to the design specification, and the reinforcement allocation comprises the following steps:
s1': analyzing and calculating the load borne by the shield segment by using the first analysis model;
s2': obtaining the most unfavorable combination of the transverse axial force and the bending moment of the shield segment;
s3': and controlling the shield segment reinforcement according to the crack width.
In the prior art, the influence of an uneven value S on the stress of a structure existing on a circumferential weld surface of a shield segment 1 is not considered, the shield segment 1 is not subjected to both transverse bending moment and longitudinal bending moment for calculation, when the shield segment 1 is subjected to reinforcement distribution, a first analysis model is used for analyzing and calculating the load borne by the shield segment 1 to obtain the worst combination of the transverse axial force and the bending moment of the shield segment 1, the problem that other stresses are caused by uneven circumferential weld surface of the shield segment 1 is not considered, reinforcement is only distributed according to the width requirement of a crack 8 during final reinforcement distribution, and reinforcement distribution is not carried out according to the actual condition after whether the load 6 is a permanent load is judged, so that the crack 8 still can be generated when the shield segment 1 is used.
In one aspect of the embodiments of the present application, a method for controlling a crack of a shield segment is provided, as shown in fig. 3, including:
s1: analyzing and calculating the load borne by the shield segment by using a first analysis model to obtain the most unfavorable combination of the transverse axial force and the bending moment of the shield segment;
s2: determining a contact mode of a circular seam part of adjacent shield segments;
s3: applying the maximum thrust load borne by the shield segment to the shield segment in a second analysis model, introducing the transverse axial force and the bending moment which are the worst combination, simulating a contact mode, and analyzing to obtain the transverse and longitudinal internal forces borne by the shield segment;
s4: and respectively carrying out reinforcement arrangement on the shield segment envelope according to the internal force of the shield segment in different stages.
According to the control method for the shield segment crack, the load 6 borne by the shield segment 1 is analyzed and calculated by using the first analysis model, and the worst combination of the transverse axial force and the bending moment of the shield segment 1 is obtained. Neglected the shield structure machine maximum thrust load F for in the current design, do not consider the two-way moment of flexure atress characteristic that shield segment 1 horizontal moment of flexure and longitudinal bending moment formed simultaneously, when shield segment 1 precision control does not reach standard, very easily cause the fracture of shield segment 1, and this kind of fracture 8 generally link up along axial development and inside and outside, cause the percolating water, endanger structure safety and tunnel operation, harm is very big. Therefore, the stress condition of the shield segment 1 is fully considered, the shield segment 1 is pertinently analyzed according to the stress stage, and the configuration of the reinforcing steel bars 4 is increased, so that the strength is increased, and the generation of cracks 8 in the shield segment 1 is greatly reduced.
Each step of the method for controlling the shield segment crack according to the embodiment of the present application is specifically described below. It is understood that the order of steps S1 and S2 of the control method can be interchanged, i.e., determining S2 and then determining S1, without affecting the implementation of the control method of the embodiment of the present application.
S1: and analyzing and calculating the load borne by the shield segment by using a first analysis model to obtain the most unfavorable combination of the transverse axial force and the bending moment of the shield segment.
In one embodiment, referring to FIG. 4, the first analytical model is a homogeneous torus model. A shield segment 1 homogeneous torus method calculation model belongs to the category of a load 6 structure method, is high in experience, is mostly carried out by adopting a finite element analysis means, is a mainstream design method in the current engineering, is analyzed by considering a shield segment 1 lining torus as an elastic homogeneous torus, is adopted by an inertial method and a correction inertial method, D in figure 4 represents the outer diameter of a segment torus, H represents the thickness of tunnel covering soil, H represents the thickness of the tunnel covering soil, and H represents the thickness of the tunnel covering soil0Indicating the height of the water level above the vault of the tunnel.
In one embodiment, the first analytical model employs a beam-spring model, as shown in FIG. 5. The method specifically considers a calculation model of the position of a joint and the rigidity of the joint while simulating the shield segment 1 by using a curved beam or a straight beam unit, generally adopts a middle whole ring and two front and rear half-width rings for calculation when a space structure model is adopted for analysis, and reflects the inter-ring force transfer effect of a longitudinal joint by using radial shear rigidity and tangential shear rigidity, and the calculation method utilizes a foundation spring to simulate a load 6, simplifies the main section of the shield segment 1 into a circular arc beam or a linear beam, considers the joint of the shield segment 1 as a rotary spring, and considers the ring joint of the shield segment 1 as a shear spring so as to evaluate the staggered joint splicing effect. The model simultaneously considers the joint rigidity, the joint position and the staggered joint splicing effect of the shield segment 1, can obtain ideal calculation results in various stratums, and is a reasonable calculation model. The computational model includes a-ring 10, B-ring 11, and C-ring 12, and also includes seam-slewing spring K1, radial shear spring K2, and tangential shear spring K3. The load 6 and the foundation spring are the same as in fig. 4.
In one embodiment, the load 6 comprises the grease pressure in the grease zone, the simultaneous grouting pressure out of the tail zone and the operational lateral load, see fig. 14-17. Fig. 14 is a schematic diagram of a transverse load of a grease zone of a shield segment in an embodiment of the present application; FIG. 15 is a schematic diagram of the lateral load grouting pressure in the synchronous grouting area of the shield segments in an embodiment of the present application; fig. 16 is a schematic diagram of static pressure in a lateral load in a synchronous grouting area of shield segments in an embodiment of the present application; fig. 17 is a schematic view of lateral loads of a shield segment in an operation period in an embodiment of the present application. The most unfavorable combination of the transverse axial force and the bending moment of the shield segment 1 is obtained by adopting the homogeneous circular ring model or the beam-spring model for calculation, the most unfavorable combination comprises the consideration of the grease pressure of a grease area, the synchronous grouting pressure of a separation tail area and the transverse load in an operation period, the stress condition of the shield segment 1 in each direction is fully considered, the stress state of the shield segment 1 is simulated more truly, and a reliable basis is provided for the simulated reinforcement of the shield segment 1.
S2: and determining the contact mode of the circular seam part of the adjacent shield segments.
In one embodiment, as shown in fig. 6, the contact means is in the form of a bump contact 7. When adopting boss contact 7, shield section of jurisdiction 1 circumferential weld face is located thrust load F one side and sets up boss 2, and shield section of jurisdiction 1 opposite side sets up to the plane, utilizes boss 2 to carry out vertical biography power between shield section of jurisdiction 1. As the shield segment 1 is a prefabricated part, the size error is inevitable, in order to reduce the adverse effect of the size error on the stress and the water resistance of the structure, the shield segment 1 manufacturing precision requirement is provided in the shield tunnel construction and acceptance standard (GB50446-2017), and when a boss contact mode is selected, the shield segment manufacturing precision is less than or equal to 0.3 mm. Because the number of the bosses 2 is large, when the annular seam surface is uneven, all the bosses 2 are difficult to be positioned on the same plane, the contact states of the bosses 2 and the adjacent shield segment 1 are divided into two types, and one type is that the bosses 2 are directly contacted with the shield segment 1; the other is that a gap is arranged between the boss 2 and the shield segment 1, and the direct contact is not formed. The quantity that boss 2 set up on the shield structure section of jurisdiction 1 as the top seal piece is 1 ~ 2, and the quantity that sets up on the shield structure section of jurisdiction 1 as standard block and adjacent block is 2 ~ 4, and a plurality of 2 intervals of boss set up. Therefore, when the boss contact 7 is adopted, the manufacturing precision of the shield segment 1 needs to be strictly controlled to be less than or equal to 0.3mm, so that more bosses 2 can be ensured to be in direct contact with the shield segment 1, and the purpose of controlling the generation of cracks 8 in the shield segment 1 is achieved.
In one embodiment, as shown in fig. 7, the contact is by way of a pad contact 5. A gasket 3 is arranged on one side, away from a thrust load F, of a circular seam surface of the shield segment 1, the other side of the shield segment 1 is arranged to be a plane, and the gasket 3 is utilized to longitudinally transfer force between the shield segments 1. When a gasket contact mode is selected, the shield segment manufacturing precision is less than or equal to 0.5 mm. When the mode of gasket contact 5 is adopted, due to the unevenness of the circumferential seam surface, the contact states of the gasket 3 and the adjacent shield segment 1 are also divided into two types, namely the gasket 3 is directly contacted with the shield segment 1; the other is that a gap is reserved between the gasket 3 and the shield segment 1, and the gasket is not in direct contact with the shield segment. The method needs to strictly control the manufacturing precision of the shield segment 1 to be less than or equal to 0.5 mm. In order to make the effect of gasket contact 5 better, the edge distance of gasket 3 is 5 ~ 10mm apart from the longitudinal joint corner of shield structure section of jurisdiction 1, and the thickness of gasket 3 is 3 ~ 4 times of the biggest permissible error of the ring width size of shield structure section of jurisdiction 1.
Further, as shown in fig. 9 and fig. 10, the shield segment 1 is provided with a schematic diagram of generating a crack 8 by a 2mm thickness gasket 3 and a 3mm thickness gasket 3, and it can be known from the diagram that when the unevenness value S of the shield segment 1 is 1mm, the situation that the crack 8 is generated by the gasket 3 with the thickness of 2mm and the stress of the gasket 3 with the thickness of 3mm is completely different, the shield segment 1 is provided with the 2mm thickness gasket 3 to generate a through crack 8, the shield segment 1 is provided with the 3mm thickness gasket 3 to generate a slight crack 8, and the crack 8 is not through, so the thickness of the gasket 3 has a certain influence on the control of the crack 8 of the shield segment 1.
Because the size error of the shield segment 1 can not be avoided, the unevenness of the annular seam surface after assembling into a ring always exists, the shield segment 1 bears the problems of larger longitudinal load and longitudinal bending moment in the construction and assembly process, and finally the shield segment 1 can be caused to generate the crack 8, so that the proper contact mode of the shield segment 1 is selected in the construction process, and the crack 8 of the shield segment 1 can be effectively prevented from being generated. Specifically, the contact mode of the shield segments can be selected according to the actual application condition of the shield segments, and when the shield segments are applied to a railway tunnel, a boss contact mode is adopted; when the device is applied to roads and other types of tunnels, a gasket contact mode is adopted.
S3: and applying the maximum thrust load borne by the shield segment to the shield segment in a second analytical model, simultaneously leading in the transverse axial force and the bending moment of the worst combination, simulating a contact mode, and analyzing to obtain the transverse and longitudinal internal forces borne by the shield segment. Referring to fig. 11 and fig. 14-17, although the shield construction load has a short action time, the load is large, the controlled factors are many, and the non-self-healing property of the structural damage and the vulnerability of the waterproof capability of the underground structure cause a large amount of penetrating cracks and water leakage hazards of the shield segments 1, even endanger the structural safety. Especially in recent years, along with the popularization on a large scale of super large diameter, ultrahigh water pressure and stratum shield tunnel, the shield construction thrust is more and more big, and the thrust is more outstanding to the influence of structure, has aggravated the shield section of jurisdiction 1 because of the not high adverse effect that causes of preparation precision. Therefore, in the simulation process of the embodiment, the maximum thrust load F borne by the shield segment 1 is led in, the transverse axial force and the bending moment which are the most unfavorable combination are led in, the contact mode is simulated, and the transverse and longitudinal internal forces borne by the shield segment 1 are obtained through analysis.
And the second analysis model is a finite element analysis model, and the finite element analysis simulates the real physical system by using a mathematical approximation method. With simple and interactive elements, a finite number of unknowns can be used to approximate a real system of infinite unknowns. Finite element analysis is solved by replacing a complex problem with a simpler one. It considers the solution domain as consisting of many small interconnected subdomains called finite elements, assuming a suitable approximate solution for each element, and then deducing the overall satisfaction conditions for solving this domain, to arrive at a solution to the problem. This solution is not an exact solution, but an approximate solution, since the actual problem is replaced by a simpler problem. Most practical problems are difficult to obtain accurate solutions, and finite elements not only have high calculation precision, but also can adapt to various complex shapes, so that the finite element becomes an effective engineering analysis means.
In an embodiment, referring to fig. 12, when the mode of boss contact 7 is adopted, the contact stiffness of the shield segment 1 is calculated according to the geometric and physical characteristics of the shield segment 1, and the contact between the shield segment 1 and the boss 2 is simulated by using a tension-free spring. The method comprises the steps of calculating the contact stiffness of a shield segment 1 according to the geometric and physical characteristics of the shield segment 1, converting the contact stiffness into spring stiffness according to the contact stiffness between the segments, simulating the contact between the shield segment 1 and a boss 2 by adopting a tension-free spring, simulating the contact between the shield segment 1 and the boss 2 by adopting spring contact 13 in a model, simulating the internal force applied when the shield segment 1 is in boss contact 7 by calculating, specifically simulating and calculating the shield segment 1 by adopting different contact models according to different contact modes, and obtaining more accurate transverse and longitudinal internal force applied to the shield segment 1.
In one embodiment, referring to fig. 13, when the mode of contact 5 of the gasket is used for simulation, the nonlinear hardened constitutive model is used for simulating the nonlinear gasket 3, and the connection between the gasket 3 and the shield segment 1 is simulated by using a tension-free spring. The method adopts a tension-free spring to simulate the spring contact between the gasket 3 and the shield segment 1, and simulates and calculates the internal force applied when the shield segment 1 adopts the gasket contact 5, so as to obtain more accurate transverse and longitudinal internal force applied to the shield segment 1.
S4: and respectively carrying out reinforcement arrangement on the shield segment envelope according to the internal force of the shield segment in different stages.
Referring to fig. 8A and 8B, according to the internal force of the shield segment 1 in different stages, the envelope of the shield segment 1 is reinforced, the stress of the shield segment 1 in different construction stages is different, the shield segment 1 is assembled, a shield tail grease area is formed, a shield tail is separated, the operation stabilization period is delayed, and the like, according to the transverse and longitudinal construction load condition borne by the structure of the shield segment 1, the stress state of the shield segment 1 is analyzed, the envelope of the shield segment 1 is reinforced in a targeted manner, the strength of the shield segment 1 is improved in a targeted manner, and the generation of the circumferential weld surface of the shield segment 1 penetrating through the crack 8 is effectively controlled.
In one embodiment, the shield segment 1 is wrapped and reinforced, when the shield segment 1 is applied to a deep beam, the shield segment 1 is reinforced according to the requirement of the deep beam, and the requirement of the deep beam is designed according to concrete structure design specification (GB 50010).
In one embodiment, the shield segment 1 is wrapped and reinforced, when the shield segment 1 is applied to a ring state, the shield segment 1 is pressed in a bidirectional eccentric mode, the shield segment 1 is reinforced according to bidirectional bias stress, and the bidirectional bias stress is reinforced according to concrete structure design specification (GB 50010).
In one embodiment, the shield segment 1 is wrapped and reinforced, and when the longitudinal load of the shield segment 1 caused by the uneven annular seam surface is a temporary load, the shield segment 1 is reinforced according to the concrete structure design specification (GB50010) and the strength requirement.
In one embodiment, the shield segment 1 is wrapped and reinforced, and when the longitudinal load of the shield segment 1 caused by the uneven circular seam surface is a permanent load, the shield segment 1 is reinforced according to the concrete structure design specification (GB50010) according to the requirements of strength and width of a crack 8.
In another aspect of the embodiments of the present application, a shield segment 1 is provided, where the shield segment 1 is manufactured by any one of the above-mentioned control methods.
In an embodiment, referring to fig. 6, in the mode of the boss contact 7, the shield segment 1 is provided with a boss 2 on one side of the circumferential joint surface where the thrust load is located, the other side of the shield segment 1 is a plane, the boss 2 is utilized to transmit force longitudinally between the shield segments 1, the number of the bosses 2 arranged on the shield segment 1 as the capping block is 1-2, the number of the bosses arranged on the shield segment 1 as the standard block and the adjacent block is 2-4, and the plurality of bosses 2 are arranged at intervals.
In an embodiment, as shown in fig. 7, in the manner of gasket contact 5, a gasket 3 is arranged on one side of a circular seam surface of the shield segment 1, which is away from a thrust load, the other side of the shield segment 1 is a plane, the gasket 3 is utilized to carry out longitudinal force transfer between the shield segments 1, the edge of the gasket 3 is 5-10 mm away from a longitudinal seam corner of the shield segment 1, and the thickness of the gasket 3 is 3-4 times of the maximum allowable error of the circular width dimension of the shield segment 1.
Under the preferred condition, when using gasket contact 5, set up the cooperation of tenon 9 and use in shield structure section of jurisdiction 1 circumferential weld department, when cooperation tenon 9 used together, the structure can be more firm.
In an embodiment, referring to fig. 7, the gasket 3 disposed on the shield segment 1 may be a flexible buffer material, or may be an elastic material such as rubber, and the shield segment 1 utilizes the gasket 3 to transmit force in the longitudinal direction, so as to reduce the generation of longitudinal bending moment, improve the durability of the shield segment 1, and prevent the generation of the segment circumferential seam surface crack 8.
The various embodiments/implementations provided herein may be combined with each other without contradiction.
The above description is only a preferred embodiment of the present application and is not intended to limit the present application, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, improvement and the like made within the spirit and principle of the present application shall be included in the protection scope of the present application.
Claims (10)
1. A control method for shield segment cracks is characterized by comprising the following steps:
analyzing and calculating the load borne by the shield segment by using a first analysis model to obtain the most unfavorable combination of the transverse axial force and the bending moment of the shield segment;
determining a contact mode of the circumferential seam parts of the adjacent shield segments;
applying the maximum thrust load borne by the shield segment to the shield segment in a second analysis model, introducing the transverse axial force and the bending moment of the worst combination, simulating the contact mode, and analyzing to obtain the transverse and longitudinal internal forces borne by the shield segment;
and respectively carrying out reinforcement arrangement on the shield segment envelope according to the internal force of the shield segment in different stages.
2. The control method according to claim 1, wherein the first analysis model is a homogeneous torus model or a beam-spring model; or the like, or, alternatively,
the load comprises the grease pressure of a grease area, the synchronous grouting pressure of a tail area of a shield and the transverse load in the operation period.
3. The control method according to claim 1, wherein the contact manner includes:
the contact mode of the boss comprises that a boss is arranged on one side, located on the thrust load, of the annular seam surface of the shield segment; or the like, or, alternatively,
and the gasket contact mode comprises that a gasket is arranged on one side, deviating from the thrust load, of the annular seam surface of the shield segment.
4. The control method according to claim 3,
when the boss contact mode is selected, the shield segment manufacturing precision is less than or equal to 0.3 mm;
when the gasket contact mode is selected, the shield segment manufacturing precision is less than or equal to 0.5 mm.
5. The control method according to claim 3, wherein in the boss contact manner, the number of the bosses provided on the shield segment as the capping block is 1 to 2, the number of the bosses provided on the shield segment as the standard block and the adjacent block is 2 to 4, and the plurality of bosses are provided at intervals.
6. The control method according to claim 3, wherein in the gasket contact mode, the distance between the edge of the gasket and the longitudinal seam corner of the shield segment is 5-10 mm; and/or the thickness of the gasket is 3-4 times of the maximum allowable error of the ring width size of the shield segment.
7. The control method according to claim 3, wherein the boss contact mode is to calculate the contact stiffness of the shield segment according to the geometric and physical characteristics of the shield segment, and a tension-free spring is used to simulate the contact between the shield segment and the boss.
8. The control method according to claim 3, wherein the gasket contact mode is a mode of simulating the nonlinear gasket by using a nonlinear hardened constitutive model, and the connection between the gasket and the shield segment is simulated by using a tension-free spring.
9. The control method according to claim 1, wherein reinforcing the shield segment envelope comprises:
reinforcing ribs of the shield segment according to the deep beam requirement;
reinforcing ribs of the shield segments according to bidirectional bias stress; and
when the longitudinal load of the shield segment caused by the uneven annular seam surface is only the construction load, the shield segment is reinforced according to the strength requirement; when the longitudinal load of the shield segment caused by the uneven annular seam surface is a permanent load, the shield segment is reinforced according to the strength requirement and the crack development width requirement.
10. A shield segment, characterized by being manufactured according to the control method of any one of claims 1 to 9.
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| CN202010017415.5A CN111236970B (en) | 2020-01-08 | 2020-01-08 | Shield segment and crack control method thereof |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN114086986A (en) * | 2021-11-30 | 2022-02-25 | 中铁第四勘察设计院集团有限公司 | Method and device applied to shield method tunnel segment of reserved pipeline installation hole |
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| CN108086995A (en) * | 2017-11-27 | 2018-05-29 | 中国铁路总公司 | A kind of shield（TBM）Tunnel pipe sheet built seam tests loading method |
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| JPH02308096A (en) * | 1989-05-23 | 1990-12-21 | Kubota Corp | Segment ring for tunnel lining |
| JPH03110298A (en) * | 1989-09-25 | 1991-05-10 | Daiho Constr Co Ltd | Tunnel |
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| CN114086986A (en) * | 2021-11-30 | 2022-02-25 | 中铁第四勘察设计院集团有限公司 | Method and device applied to shield method tunnel segment of reserved pipeline installation hole |
| CN114086986B (en) * | 2021-11-30 | 2023-12-22 | 中铁第四勘察设计院集团有限公司 | Method and device applied to shield-method tunnel segment with reserved pipeline installation pore canal |
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| CN111236970B (en) | 2021-06-11 |
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