Large shield tail segment device in water-rich stratum and construction method

Abstract

The invention belongs to the technical field of shield construction, particularly relates to the field of shield construction of water-rich stratums, in particular to a large shield tail segment device in the water-rich stratums and a construction method, and solves the problems that shield segments in the water-rich stratums are prone to floating upwards and poor in water stopping effect. A gap between the periphery of a pipe piece and a stratum is filled through arc-shaped air bag grouting, floating of the pipe piece can be limited, a formed water stop ring can prevent underground water behind a shield tunneling machine from flowing to a soil bin, the pipe piece comprises a pipe piece unit, an arc-shaped mounting groove is formed in the outer arc face of the pipe piece unit in the peripheral direction, and an arc-shaped air bag is assembled in the mounting groove; when slurry is not injected into the arc-shaped air bag, the outer side of the arc-shaped air bag is located in the mounting groove, and when slurry is injected into the arc-shaped air bag, the outer side of the arc-shaped air bag extends out of the mounting groove.

Description

Technical Field

[0001] The present invention belongs to the technical field of shield construction, especially the shield construction in water-rich strata, and specifically relates to a large shield tail segment device and construction method in water-rich strata. Background Art

[0002] In recent years, when a shield machine tunnels in water-rich strata, the segments are prone to floating up after exiting the shield tail. The floating up of the segments will cause damage and water leakage of normal segments, bringing potential hazards to the normal operation of the shield tunnel. The existing solutions are: when the shield machine tunnels in water-rich strata, artificially lower the attitude of the shield machine, or, synchronously inject single-component slurry + secondary grouting with two-component slurry. This method is feasible for good geological conditions, but for soft strata such as silty soil, especially when passing through sensitive structures such as dams, old houses, bridges, and underground passages at close range, the deformation control effect is poor, and in severe cases, it will often cause excessive settlement of the structures, further leading to cracking.

[0003] At the same time, in water-rich strata, when opening the shield chamber, it is necessary to control the flow of groundwater, especially to control the water flow behind the shield from entering the soil chamber. The existing technology is: applying a water-stop ring hoop to the segments that have exited the shield tail to play a role in controlling the flow of groundwater behind the tunnel into the soil chamber. However, affected by factors such as hydrogeology and grouting quality, the water-stop effect is not good.

[0004] In addition, in actual projects, the shield machine often encounters underground obstacles (such as boulders, pipelines, etc.) or needs to open the chamber for treatment after the cutter head forms mud cakes. After the shield machine stops in these cases, the groundwater runoff behind the shield tail will recharge the excavation face, resulting in an increase in the water content of the soil mass on the excavation face and a decrease in the effective shear strength, which is likely to cause instability of the excavation face. Summary of the Invention

[0005] The present invention provides a large shield tail segment device and construction method in water-rich strata, which solves the problems that the shield segments in water-rich strata are prone to floating up and the water-stop effect is not good. Through a special segment device, the gap between the outer periphery of the segment and the strata is filled with slurry by an arc-shaped airbag grouting, which can limit the floating up of the segment, and the formed water-stop ring can prevent the groundwater behind the shield machine from flowing into the soil chamber.

[0006] The present invention is realized through the following technical solutions: A large shield tail segment device in water-rich strata, including a segment unit. An arc-shaped installation groove is arranged along the outer peripheral direction of the outer arc surface of the segment unit, and an arc-shaped airbag is assembled in the installation groove; At least two airbag connecting pipes communicating with the arc-shaped airbag are arranged on the inner arc surface of the segment unit; When the arc-shaped airbag is not injected with slurry, the outer side of the arc-shaped airbag is located in the installation groove, and when the arc-shaped airbag is injected with slurry, the outer side of the arc-shaped airbag extends out of the installation groove.

[0007] Furthermore, the cross-section of the installation groove is U-shaped, and the installation groove is welded integrally with the built-in longitudinal reinforcement of the segment unit.

[0008] Furthermore, the bottom surface of the arc-shaped airbag is fixed in the installation groove through an adhesive layer, and a protective rubber strip with a thickness of 0.5 - 0.8 mm is pasted on the outer side of the arc-shaped airbag.

[0009] Furthermore, the arc-shaped airbag is made of rubber material.

[0010] Furthermore, the number of the airbag connecting pipes is more than three, one of the airbag connecting pipes serves as an exhaust pipe, and the remaining airbag connecting pipes serve as grouting pipes and are provided with threaded interfaces.

[0011] A construction method for large shield tail segments in a water-rich stratum includes the following steps: S10. Fabricate the segment unit of the large shield tail segment device in the water-rich stratum as described above; S20. Install the arc-shaped airbag in the installation groove of the segment unit; S30. First, the shield machine assembles the segment units to form a segment ring; Then, according to the shield tunneling attitude, segment attitude, groundwater condition, segment floating data and control requirements, determine the grouting positions of the arc-shaped airbags of each segment unit, and divide the airbag connecting pipes into grouting pipes and exhaust pipes; S40. Install a ball valve, a grouting pressure gauge in sequence at the threaded joint of the grouting pipe, connect the grouting pipeline and the grouting pump, and start the grouting pump to inject grout into each arc-shaped airbag through the grouting pipe; S50. During the process of injecting grout into the arc-shaped airbag, the outer side of the arc-shaped airbag expands and protrudes out of the segment outer surface. The expanded arc-shaped airbag fills the gap between the outer periphery of the segment and the stratum. As the grouting volume increases, when slurry flows out of the exhaust pipe and the grouting reaches the set pressure, close the ball valve and stop grouting the arc-shaped airbag; S60. When the arc-shaped airbags of each segment unit are filled with grout, the arc-shaped airbags form a water stop ring on the outer periphery of the whole ring of segments, and the water stop ring is used to prevent the groundwater behind the shield machine from flowing into the soil bin; S70. Inject grout into the remaining gaps between the outer periphery of the segment and the stratum through grouting anchor rods to complete the grouting operation between the whole segment ring and the stratum.

[0012] Furthermore, it also includes S80. After the shield propulsion cylinder meets the segment assembly stroke, continue to assemble segments. After the segments are assembled, synchronous grouting is carried out during tunneling, and the shield construction is organized according to the normal shield tunneling process; for each ring of segment units of the segment device described in claim 1 constructed, at least one ring of ordinary segments is constructed in shield construction.

[0013] Further, in step S30, according to the assembly postures of the segment units, the airbag connecting pipes are divided. The airbag connecting pipe at the highest position is divided into an exhaust pipe, and the remaining airbag connecting pipes are divided into grouting pipes.

[0014] Further, in step S10, the steps for manufacturing the segment units of the above segment device are as follows: S1001. Install the mold of the airbag connecting pipe on the segment casting mold; S1002. Prefabricate an arc-shaped embedded groove as the installation groove, and spot-weld the installation groove to the longitudinal bars of the segment reinforcement cage. The distances from both ends of the installation groove to the two ends of the segment are equal, and the distance from the end of the installation groove to the end of the segment is within 30 mm; S1003. Fill the installation groove with foam-like materials to prevent concrete from flowing in during concrete pouring; S1004. Lift and place the reinforcement cage into the mold according to the segment production process, pour concrete, and complete the production and curing of the segment.

[0015] Further, in step S20, after the segments reach the construction site, clean the filler in the installation groove, clean the burrs at the corners of the installation groove, evenly apply an adhesive to the bottom of the installation groove, then fix and install the arc-shaped airbag, and paste a 0.5-mm-thick protective rubber strip on the outer surface of the arc-shaped airbag.

[0016] The beneficial effects achieved by the present invention compared with the prior art are as follows: 1. The present invention provides a large shield tail segment device in a water-rich stratum. An arc-shaped airbag is assembled in the installation groove on the outer arc surface of the segment unit. When the arc-shaped airbag is not injected with slurry, the outer side of the arc-shaped airbag is located in the installation groove. When the arc-shaped airbag is injected with slurry, the outer side of the arc-shaped airbag extends out of the installation groove. When the grouting pressure is reached, the arc-shaped airbag is in close contact with the stratum to control the floating of the segment and prevent groundwater from flowing into the soil bin; 2. The present invention provides a construction method for a large shield tail segment in a water-rich stratum. After the shield machine assembles the segment units to form a segment ring, start the grouting pump to inject slurry into each arc-shaped airbag through the grouting pipe; the amount of mortar filled in each arc-shaped airbag can be controlled separately, which can not only control the floating of the segment, but also adjust the pressure acting on the segment, making the force on the shield tail segment more balanced, so as to realize the circumferential pressure regulation of the segment; When the arc-shaped airbags of each segment are filled with mortar, they expand and squeeze each other to form a circumferential closed water-stop ring, which can block the groundwater or slurry in the soil layer behind the shield tail from flowing to the excavation face and the shield shell of the shield machine, avoid the instability of the excavation face of the shield machine, and at the same time prevent the shield shell from being caked with mud and causing too large frictional force between the shield shell and the stratum; 3. In the present invention, the grouting of the arc-shaped airbag ensures that the grout is not diluted or washed away by groundwater. After the grout solidifies in the airbag, it has good strength, avoiding the problem that fine particles in the grout are easily washed away in flowing water. 4. Through the present invention, when opening the chamber in a water-rich stratum, a water stop ring is formed by the airbag at the shield tail, which can effectively prevent the adverse impact of the groundwater runoff at the shield tail on the stability of the excavation face during the shutdown operation of the shield machine in the high-pressure soft soil stratum, and can effectively prevent the groundwater from flowing into the soil chamber, which is beneficial to improving the safety of shield chamber opening. Description of the Drawings

[0017] Figure 1 It is a schematic plan view of the segment device at the shield tail of a large shield in the water-rich stratum described in the present invention Figure 2 is Figure 1 Schematic view A-A in Figure 3 It is a schematic view of the arc-shaped airbag and the airbag connecting pipe described in the present invention Figure 4 It is a schematic view of the working state of the arc-shaped airbag described in the present invention Figure 5 It is a schematic view of the installation of the arc-shaped airbag on the integral ring segment described in the present invention In the figure: 1. Segment unit, 2. Installation groove, 3. Arc-shaped airbag, 4. Airbag connecting pipe, 5. Grouting pipe, 6. Exhaust pipe. Detailed Embodiments

[0018] Next, the technical solutions in the embodiments of the present application will be clearly and completely described in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments of the present application, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present application.

[0019] In the description of the invention, it should be understood that the orientation or positional relationship indicated by terms such as "front", "rear", "upper", "lower", "left", "right", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present invention.

[0020] Such as Figure 1 、 Figure 2 、 Figure 3As shown in the figure, this embodiment discloses a large shield tail segment device in a water-rich stratum, which mainly includes a segment unit 1, an installation groove 2, and an arc-shaped airbag 3. Among them, the segment unit 1 is formed by pouring concrete into a steel reinforcement cage, and the installation groove 2 is made of a precast arc-shaped embedded groove. The cross-section of the installation groove 2 is U-shaped, and the arc-shaped installation groove 2 is embedded along the outer circumference direction of the segment unit 1 on the outer arc surface of the segment unit 1. The installation groove 2 is welded to the internal longitudinal bars of the segment unit 1 as a whole. The distances from both ends of the installation groove to both ends of the segment unit are equal, and the distance from the end of the installation groove to the end of the segment is controlled within 5 mm.

[0021] The arc-shaped airbag 3 is made of rubber material. The bottom surface of the arc-shaped airbag 3 is fixed in the installation groove 2 through an adhesive layer. A protective rubber strip with a thickness of 0.5 - 0.8 mm is pasted on the outer side of the arc-shaped airbag 3 to improve the wear resistance with the stratum. Three airbag connecting pipes 4 communicating with the arc-shaped airbag 3 are embedded in the inner arc surface of the segment unit 1. One of the airbag connecting pipes 4 serves as an exhaust pipe 6, and the remaining two airbag connecting pipes 4 serve as grouting pipes 5 and are provided with threaded interfaces. When the arc-shaped airbag 3 is not filled with slurry, the outer side of the arc-shaped airbag 3 is located in the installation groove 2. When the arc-shaped airbag 3 is filled with slurry, the outer side of the arc-shaped airbag 3 extends out of the installation groove 2.

[0022] Based on the above large shield tail segment device in a water-rich stratum, this embodiment also discloses a construction method for a large shield tail segment in a water-rich stratum, including the following steps: S10. Fabricate the segment unit 1 of the above large shield tail segment device in a water-rich stratum; This step specifically includes the following steps: S1001. Install the mold of the airbag connecting pipe on the basis of the existing segment casting mold; S1002. Use the precast arc-shaped embedded groove as the installation groove, and spot-weld the installation groove to the longitudinal bars of the segment steel reinforcement cage. The distances from both ends of the installation groove to both ends of the segment are equal, and the distance from the end of the installation groove to the end of the segment is within 30 mm; S1003. Fill the installation groove with foam-like materials to prevent concrete from flowing in during concrete pouring; S1004. Lift and place the steel reinforcement cage into the mold according to the segment production process, pour concrete, and complete segment production and curing; S20. After the segment unit arrives at the construction site, clean the filler in the installation groove, clean the burrs at the corners of the installation groove, evenly apply an adhesive to the bottom of the installation groove, then fix and install the arc-shaped airbag 3 in the installation groove 2, and paste a 0.5 mm thick protective rubber strip on the outer surface of the arc-shaped airbag 3; S30. First, the shield machine assembles each segment unit 1 to form a segment ring; Then, according to the shield tunneling attitude, segment attitude, groundwater conditions, segment floating data and control requirements, determine the grouting positions of the arc-shaped airbags 3 of each segment unit 1, and divide the airbag connecting pipes 4 into grouting pipes 5 and exhaust pipes 6; According to the assembly attitude of each segment unit, divide the airbag connecting pipes. The principle of reference is that the airbag connecting pipe at the highest position is divided into the exhaust pipe, and the remaining airbag connecting pipes are divided into grouting pipes; S40. Install a ball valve, a grouting pressure gauge in sequence at the threaded joint of the grouting pipe 5, connect the grouting pipeline and the grouting pump. A diaphragm pressure gauge can be selected for the grouting pressure gauge. Start the grouting pump and inject the grout into each arc-shaped airbag 3 through the grouting pipe 5; S50. As Figure 4 shown, during the process of injecting grout into the arc-shaped airbag 3, the outer side of the arc-shaped airbag 3 expands and protrudes from the segment outer surface, and the cross-section is arched. The expanded arc-shaped airbag 3 fills the gap between the outer periphery of the segment and the formation. As the grouting volume increases, when the exhaust pipe 6 has grout flowing out and the grouting reaches the set pressure, close the ball valve and stop grouting the arc-shaped airbag 3; In this step, the amount of mortar filled in each arc-shaped airbag can be controlled individually. In this way, not only can the segment floating be controlled, but also the pressure acting on the segment can be adjusted, making the force on the segments at the shield tail more balanced, so as to realize the circumferential pressure control of the segments; S60. When the arc-shaped airbags 3 of each segment unit 1 are filled with grout, the arc-shaped airbags 3 form a water-stop ring on the outer periphery of the whole ring of segments, and the water-stop ring is used to prevent the groundwater behind the shield machine from flowing into the soil bin; S70. As Figure 5 shown, grout the gaps at the remaining positions between the outer periphery of the segment and the formation through the grouting anchor rods to complete the grouting operation between the whole pipe ring and the formation; S80. After the shield propulsion cylinder meets the segment assembly stroke, continue to assemble the segments. Synchronous grouting is carried out while tunneling after the segments are assembled. Organize the shield construction according to the normal shield tunneling process; for each ring of segment units of the above segment device constructed, at least one ring of ordinary segments is constructed by the shield. For example, according to the actual situation, the ordinary segments and the above segment device can be alternately shielded to form a ring.

[0023] Through the above construction method, after the arc-shaped airbags of each segment are filled with mortar, they expand and squeeze each other to form a circumferential closed water-stop ring. The arc-shaped airbags are closely attached to the formation to control the segment floating. At the same time, it can block the groundwater or grout in the soil layer behind the shield tail from flowing to the shield machine excavation face and the shield shell, avoid the instability of the shield machine excavation face, and also prevent the shield shell from being caked with mud, resulting in too large frictional force between the shield shell and the formation.

Claims

1. A shield tail segment device for a large shield machine in a water-rich stratum, characterized in that: It comprises a tube sheet unit (1), wherein the outer arc surface of the tube sheet unit (1) is provided with an arc-shaped installation groove (2) along the outer circumferential direction, and the installation groove (2) is equipped with an arc-shaped air bag (3); The inner arc surface of the tube sheet unit (1) is provided with at least two airbag connecting tubes (4) connected to the arc-shaped airbag (3); When the arc-shaped airbag (3) is not injected with slurry, the outer side of the arc-shaped airbag (3) is located in the installation groove (2); when the arc-shaped airbag (3) is injected with slurry, the outer side of the arc-shaped airbag (3) extends out of the installation groove (2).

2. The tail tube segment device for a large shield machine in a water-rich stratum according to claim 1 is characterized in that: The cross section of the installation groove (2) is U-shaped, and the installation groove (2) and the built-in longitudinal reinforcement of the segment unit (1) are welded together.

3. The tail tube segment device for a large shield machine in a water-rich stratum according to claim 1, characterized in that: The bottom surface of the arc-shaped airbag (3) is fixed in the mounting groove (2) via an adhesive layer, and a protective adhesive strip with a thickness of 0.5-0.8 mm is adhered to the outer side of the arc-shaped airbag (3).

4. The shield tail segment device for a large shield machine in a water-rich stratum according to claim 3 is characterized in that: The arc-shaped airbag (3) is made of rubber material.

5. The tail tube segment device for a large shield machine in a water-rich stratum according to any one of claims 1 to 4, characterized in that: The number of the airbag connecting tubes (4) is three or more, one of which is used as an exhaust pipe (6), and the remaining airbag connecting tubes (4) are used as grouting pipes (5) and are provided with threaded interfaces.

6. A method for constructing a large shield tail segment in a water-rich stratum, characterized in that: The following steps are involved: S10, manufacturing the segment unit (1) of the tail segment device of a large shield machine in a water-rich stratum according to claim 1; S20, installing the arc-shaped airbag (3) in the installation groove (2) of the tube segment unit (1); S30, first, the shield machine assembles the segment units (1) to form a pipe ring; Then, according to the shield tunneling posture, the segment posture, the groundwater conditions, the segment floating data and the control requirements, the grouting position of the arc-shaped airbag (3) of each segment unit (1) is determined, and the airbag connecting pipe (4) is divided into a grouting pipe (5) and an exhaust pipe (6); S40, sequentially installing a ball valve and a grouting pressure gauge on the threaded joint of the grouting pipe (5), connecting the grouting pipeline and the grouting pump, and starting the grouting pump to inject slurry into each arc-shaped air bag (3) through the grouting pipe (5); S50, during the process of injecting slurry into the arc-shaped airbag (3), the outer side of the arc-shaped airbag (3) expands and protrudes from the outer surface of the pipe segment, and the expanded arc-shaped airbag (3) fills the gap between the outer periphery of the pipe segment and the formation. As the grouting amount increases, when slurry flows out of the exhaust pipe (6) and the grouting reaches the set pressure, the ball valve is closed to stop grouting the arc-shaped airbag (3); S60, after the slurry is injected into the arc-shaped airbags (3) of each segment unit (1), the arc-shaped airbags (3) form a water stop ring on the outer periphery of the entire ring of segments, and the water stop ring is used to prevent groundwater behind the shield machine from flowing into the soil bin; S70, grouting is performed on the remaining gaps between the outer periphery of the pipe segment and the stratum through grouting anchor rods to complete the grouting operation between the entire pipe ring and the stratum.

7. The method for constructing a large shield tail segment in a water-rich stratum according to claim 6, characterized in that: Also includes, S80. After the shield thrust cylinder meets the segment assembly stroke, continue to assemble the segments. After the segment assembly is completed, synchronous grouting is carried out while excavating, and the shield construction is organized according to the normal shield excavation process; for each ring of segment units of the large shield tail segment device in the water-rich stratum as described in claim 1, the shield constructs at least one ring of ordinary segments.

8. The method for constructing a large shield tail segment in a water-rich stratum according to claim 6, characterized in that: In step S30, the airbag connecting pipes are divided according to the assembly posture of each pipe segment unit, the airbag connecting pipe at the highest position is divided into the exhaust pipe, and the remaining airbag connecting pipes are divided into the grouting pipes.

9. The method for constructing a large shield tail segment in a water-rich stratum according to claim 6, characterized in that: In step S10, manufacturing the segment unit of the tail segment device of the large shield machine in the water-rich formation according to claim 1 comprises the following steps: S1001. Installing a mold for the airbag connecting pipe on the segment casting mold; S1002. Use the prefabricated arc-shaped embedded groove as the installation groove, and fix the installation groove and the longitudinal reinforcement of the segment reinforcement cage by spot welding. The distance between the two ends of the installation groove and the two ends of the segment is equal, and the distance between the end of the installation groove and the end of the segment is within 30mm; S1003. Fill the installation groove with foam material to prevent the concrete from flowing into it during concrete pouring; S1004. According to the segment production process, the steel cage is hoisted into the mold, concrete is poured, and the segment production and maintenance are completed.

10. The method for constructing a large shield tail segment in a water-rich stratum according to claim 9, characterized in that: In step S20, after the pipe segment arrives at the construction site, the filler in the installation groove is cleaned, the burrs on the corners of the installation groove are cleaned, the adhesive is evenly applied to the bottom of the installation groove, and then the arc airbag is fixed and installed, and a 0.5 mm thick protective tape is pasted on the outer surface of the arc airbag.

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