Method for controlling station deformation caused by shield penetrating and cutting pile foundation

Abstract

The invention discloses a method for controlling station deformation caused by shield penetrating and cutting of a pile foundation, and relates to the technical field of constructional engineering, the method comprises the following steps: step 1, before shield excavation, grouting reinforcement is carried out on a soil body around the pile foundation to be penetrated and cut and a soil body between piles; 2, before a shield penetrates through and cuts a pile foundation, a settlement monitoring system is arranged for a station; thirdly, the shield tunneling machine conducts tunnel excavation underground, and part of pile foundations and soil bodies between the piles are cut off step by step; and fourthly, grouting materials are injected into the underground structure through the grouting pipeline. According to the method, the soil bodies among the piles are reinforced in advance, so that the soil bodies around the piles can be reinforced in advance, the influence on the underground construction environment is small, and urban underground space resources are effectively saved. The settlement deformation of a station in the shield pile penetrating and cutting process is monitored and fed back in real time, the settlement amount of a building in the shield pile cutting process is strictly controlled in cooperation with synchronous grouting reinforcement and emergency supplementary grouting reinforcement, and the stability of an underground structure is improved.

Description

Technical Field

[0001] The invention relates to the technical field of construction engineering, and in particular to a method for controlling deformation of a station caused by a shield machine penetrating a pile foundation. Background Art

[0002] Shield construction is an advanced construction technology used in underground tunnel or pipeline construction. Shield construction can reduce disturbance to the ground surface, which is especially important when constructing in urban central areas or environmentally sensitive areas. It can also be applied to various geological conditions. It is a safe and efficient underground tunnel construction method, which plays an important role in urban infrastructure construction. During shield construction, since the diameter of the cutterhead is larger than the outer diameter of the prefabricated segment, there is a certain gap between the outside of the segment and the soil. Grouting can be used to fill these gaps and reduce the settlement of the residual pile end. At the same time, during the shield excavation process, the disturbance of the soil by the shield machine causes the loss of soil around the pile, and part of the soil separates from the side of the pile foundation, which reduces the friction resistance on the pile side and the bearing capacity of the pile foundation.

[0003] Most of the existing construction devices for preventing pile foundation settlement are constructed by opening multiple inclined guide pipes around the pile foundation, making one end of the pipe contact the pile base body, and then filling it with cement. However, this method is inconvenient to install, and the pile base body is prone to collision during installation, affecting the contact between the pile foundation and the surrounding soil and the stability of the pile base body. Summary of the invention

[0004] The purpose of the present invention is to provide a method for controlling the deformation of a station caused by a shield machine cutting through a pile foundation, so as to solve the problem that the existing construction device for preventing pile foundation settlement is installed by opening a plurality of inclined guide pipes around the pile foundation, which is inconvenient to install and is prone to collision with the pile foundation during the installation process, thereby affecting the contact between the pile foundation and the surrounding soil and the stability of the pile foundation.

[0005] In order to achieve the above object, the present invention provides a method for controlling the deformation of a station caused by a shield machine cutting through a pile foundation, comprising the following steps: Step 1: Before shield excavation, grouting is performed to reinforce the soil around the pile foundation to be cut through at the bottom of the station body and the soil between the piles; Step 2: Before the shield machine penetrates the pile foundation, a settlement monitoring system is installed at the station to conduct dynamic real-time monitoring and feedback of the settlement deformation of the station during the process of the shield machine penetrating the pile foundation. Step 3: The shield machine excavates the tunnel underground, gradually removing part of the pile foundation and the soil between the piles, while removing the residue at the rear; Step 4: In front of the shield machine excavation, grouting material is injected into the underground structure through the grouting pipe to fill the gaps and cracks in the soil layer to form a reinforcement curtain; Step 5: After the shield machine has advanced a certain distance, the segments behind the shield machine begin to be spliced ​​together to form the basic structure of the assembled prefabricated pipeline; Step six: After the segments are spliced, grouting is immediately carried out at the shield tail. When the shield segments of the shield machine are separated from the shield tail, grouting is carried out simultaneously at the shield tail of the shield machine to fill the construction gap between the shield body of the shield machine and the lining structure in time.

[0006] As a preferred solution of the present invention, in the step one, before the shield excavation, the grouting pipe is buried around the station body, and the grouting pipe is inserted into the soil in an oblique manner, and the end of the grouting pipe reaches the area to be reinforced. After the reinforcement is completed, the grouting pipe is completely pulled out and filled with filling materials.

[0007] As a preferred solution of the present invention, the grouting pipe is a rigid sleeve valve pipe, and the grouting pipe passes through the supplementary grouting pipeline reserved in the pipe segment into the surrounding soil.

[0008] As a preferred embodiment of the present invention, in step 1, the grouting process for pile foundation reinforcement is: The first step is to evaluate the soil area around the pile above the tunnel to be excavated and select the appropriate grouting material according to the specific ground conditions; The second step is to bury the grouting pipe and use professional grouting equipment to inject the slurry into the stratum to be reinforced so that the slurry can fully fill the voids in the soil layer; The third step, after the grouting is completed, is to carry out post-processing work, clean up the excess slurry and repair the construction traces, and finally carry out testing and evaluation work.

[0009] As a preferred solution of the present invention, in the step 2, during the shield tunneling through the pile foundation, the station settlement is dynamically monitored in real time to obtain timely result feedback; If the monitored deformation and settlement of the station is within the permissible range, the shield tunneling work will continue; If the monitored settlement is too large and exceeds the warning value or the station has uneven settlement, the shield excavation work will be stopped immediately and additional grouting will be carried out to control the problem of excessive settlement or uneven settlement of the station. Shield excavation construction will be continued after the monitored settlement returns to normal.

[0010] As a preferred embodiment of the present invention, in step 4, a cutter disc is provided on the shield machine, the diameter of the cutter disc is larger than the outer diameter of the segment, and there is a gap between the outside of the segment and the soil.

[0011] As a preferred solution of the present invention, in step five, the pipe segments are prefabricated pipe segments, and the pipe segments are fixed by bolts when splicing.

[0012] As a preferred embodiment of the present invention, in step six, the shield machine transports the slurry to the gap between the shield tunnel and the surrounding soil. Before the slurry is completely solidified, the assembled prefabricated pipe is located in the shield tunnel. Only when the slurry is solidified, the assembled prefabricated pipe is connected with the surrounding soil and the ends of the residual piles.

[0013] As a preferred solution of the present invention, in step 4, the grouting reinforcement needs to be synchronously controlled with the shield excavation, and the propulsion speed of the shield machine and the injection speed of the grouting material should be coordinated and consistent.

[0014] Compared with the prior art, the present invention has the following beneficial effects: 1. The present invention reinforces the soil between piles before the shield cuts through the pile foundation, which can realize the early reinforcement of the soil around the pile, has little impact on the underground construction environment, and has low construction cost and short construction period, effectively saving urban underground space resources. The settlement and deformation of the station during the shield cutting through the pile foundation are monitored and fed back in real time, and the settlement of the building during the shield cutting pile foundation is strictly controlled by synchronous grouting reinforcement and emergency supplementary grouting reinforcement. The project is of great significance and has significant social and economic benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the implementation methods of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for the implementation methods or the description of the prior art. Obviously, the drawings in the following description are only exemplary, and for ordinary technicians in this field, other implementation drawings can be derived from the provided drawings without creative work.

[0016] Figure 1 A structural schematic diagram of a method for controlling station deformation caused by a shield machine cutting through a pile foundation is provided for an embodiment of the present invention; Figure 2 A structural schematic diagram of a reinforcement area is provided for an embodiment of the present invention; Figure 3 A schematic diagram of a partial structure of a pipe segment is provided for an embodiment of the present invention; Figure 4 A schematic diagram of a shield tunneling through a pile foundation is provided for an embodiment of the present invention; Figure 5 A side view of shield excavation is provided for an embodiment of the present invention.

[0017] The numbers in the figure represent the following: 1. Soil; 2. Pile foundation; 3. Tunnel to be excavated; 4. Pipe segment; 5. Grouting pipe; 6. Shield tunnel; 7. Shield machine; 8. Supplementary grouting pipe; 9. Cutter head; 10. Gap; 11. Station body; 12. Assembled prefabricated pipe. DETAILED DESCRIPTION

[0018] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0019] like Figure 1-Figure 5 As shown, a method for controlling station deformation caused by shield tunneling through pile foundations comprises the following steps: Step 1: Before shield excavation, grouting is performed to reinforce the surrounding soil 1 and the soil 1 between the piles at the bottom of the station body 11 where the pile foundation 2 is to be cut; Step 2: Before the shield machine penetrates the pile foundation 2, a settlement monitoring system is installed at the station to dynamically monitor and feedback the settlement deformation of the station during the process of the shield machine penetrating the pile foundation; Step 3: The shield machine 7 excavates the tunnel underground, gradually removing part of the pile foundation 2 and the soil 1 between the piles, and removing the residue at the rear; Step 4: In front of the shield machine 7 excavation, grouting material is injected into the underground structure through the grouting pipe 5 to fill the gaps and cracks in the soil layer to form a reinforcement curtain; Step 5: After the shield machine 7 advances a certain distance, the segments 4 behind the shield body of the shield machine 7 begin to be spliced ​​to form the basic structure of the assembled prefabricated pipeline 12; Step six, after the segment 4 is spliced, grouting is immediately performed at the shield tail. When the shield segment 4 of the shield machine 7 is separated from the shield tail, grouting is performed synchronously at the shield tail of the shield machine 7 to fill the building gap between the shield body of the shield machine 7 and the lining structure in time.

[0020] Among them, in step one, before shield excavation, the grouting pipe 5 is buried around the station body 11, and the grouting pipe 5 is inserted into the soil 1 in an oblique manner. The end of the grouting pipe 5 reaches the area to be reinforced to ensure the reinforcement effect. After the reinforcement is completed, all the grouting pipes 5 are pulled out and filled with filling materials to maintain the stability of the formation.

[0021] Furthermore, the grouting pipe 5 is a rigid sleeve valve pipe, and the grouting pipe 5 penetrates into the surrounding soil 1 from the supplementary grouting pipe 8 reserved in the pipe segment 4. The grouting pipe 5 of synchronous grouting reinforcement during the construction process is to penetrate into the surrounding soil 1 from the supplementary grouting pipe 8 reserved in the prefabricated pipe segment 4, so that the slurry can be fully integrated with the surrounding strata during grouting reinforcement, thereby improving the reinforcement effect.

[0022] In step 1, the grouting process for reinforcing the pile foundation 2 is: In the first step, in order to pre-reinforce the soil around the pile above the tunnel 3 to be excavated, the soil around the pile 1 area above the tunnel 3 to be excavated is first evaluated, and the appropriate grouting material is selected according to the specific stratum conditions. The second step is to bury the grouting pipe 5 and use professional grouting equipment to inject the slurry into the stratum to be reinforced. During the grouting process, the pressure, flow rate and speed of the grouting need to be controlled so that the slurry can fully fill the gaps in the soil layer and achieve the expected reinforcement effect.

[0023] The third step is to carry out post-processing work after the grouting is completed, clean up the excess slurry and repair the construction traces, and finally carry out testing and evaluation work to ensure that the effect of grouting reinforcement meets the requirements.

[0024] In step 2, a settlement monitoring system is installed at the station before the shield cuts through the pile foundation. The settlement detection system is a prior art and is generally evenly arranged along the length or width of the station, or evenly arranged along the shield excavation direction. If the impact of the shield crossing on the track is to be monitored, the monitoring instrument needs to be arranged on the track bed. The working condition mentioned in the present invention is that the shield crosses perpendicularly to the length direction of the station, so the monitoring instrument can be evenly arranged along the shield excavation direction.

[0025] During the process of shield tunneling through pile foundations, dynamic and real-time monitoring and feedback of the station settlement and deformation during the process of shield tunneling through pile foundations are carried out. If the monitored deformation and settlement of the station is within the allowable range, and the allowable deformation value has different requirements according to the engineering construction specifications in different places, the shield excavation work will continue; if the monitored settlement is too large and exceeds the warning value or the station has uneven settlement, grouting is required. The additional grouting can have the effect of fixed-point grouting, that is, if the settlement at a certain place exceeds the allowable deformation value, slurry is added at that place to stabilize the stratum there and control the settlement rate until the settlement stabilizes.

[0026] The pile foundation 2 is the foundation of the station body 11. Friction piles are generally used in soft soil areas to provide support force by relying on the friction between the pile foundation and the surrounding soil layer.

[0027] Furthermore, the shield machine (7) is provided with a cutterhead (9), which is an important component of the shield machine 7 and plays a role in cutting the stratum and the reinforced concrete pile. The excavation process of the shield machine 7 is the process in which the cutterhead 9 cuts the soil 1 and the pile foundation 2 and advances. In the process of the shield machine penetrating the pile foundation in step 3, the working condition selected by the present invention is that the shield machine 7 directly breaks the pile foundation 2. Prior to this, it is required to make certain adaptive modifications to the cutterhead 9, the cutter and the screw conveyor of the shield machine 7. The strength requirement of the cutterhead 9 and the cutter is capable of breaking the reinforced concrete. For projects where the crossing conditions are reserved in advance, such as the pile foundation adopts glass fiber concrete, the strength requirement of the cutterhead 9 of the shield machine 7 can be appropriately reduced.

[0028] The installation of the segments 4 is another function of the shield machine 7. After the shield machine 7 advances a certain distance, the rear part of the shield body of the shield machine 7 begins to splice the prefabricated segments to form the basic structure of the assembled prefabricated pipeline 12.

[0029] In step five, the pipe segment 4 is a prefabricated pipe segment, and the pipe segment 4 is fixed by bolts when splicing. In addition, in step four, the diameter of the cutter head 9 is larger than the outer diameter of the pipe segment 4, and there is a gap 10 between the outside of the pipe segment 4 and the soil 1, which can be filled by grouting to reduce the settlement of the pile end. The diameter of the cutter head 9 is larger than the diameter of the shield body, so after the pipe segment 4 is spliced, there will still be a certain gap 10 between the pipe segment and the surrounding soil 1. The shield machine 7 implements an assembly function, and the workers tighten the bolts connecting the pipe segments 4 in time.

[0030] After the segments 4 are spliced, the shield tail grouting should be carried out immediately. The shield tail grouting is also one of the functions of the shield machine 7. In step six, the shield machine 7 transports the slurry to the gap 10 between the shield tunnel 6 and the surrounding soil 1. Before the slurry is completely solidified, the assembled prefabricated pipe 12 is located in the shield tunnel 6. Until the slurry solidifies, the assembled prefabricated pipe 12 is connected with the surrounding soil 1 and the pile end of the residual pile. The soil 1 here is the soil 1 around the shield excavation. The excavated part of the soil 1 will be removed in time through the screw conveyor.

[0031] In step 4, the grouting reinforcement needs to be synchronously controlled with the shield excavation, and the advancing speed of the shield machine 7 is coordinated with the injection speed of the grouting material to ensure that the shield tunnel 6 is reinforced and supported in time during the excavation process.

[0032] The present invention can realize the advance reinforcement of the soil around the piles by reinforcing the soil 1 between the piles in advance, which has little impact on the underground construction environment, and has fast construction progress, low construction cost, high construction safety, and effectively saves urban underground space resources. The settlement deformation of the station during the shield cutting through the pile foundation is monitored and fed back in real time, and the settlement of the building during the shield cutting pile foundation is strictly controlled by synchronous grouting reinforcement and emergency supplementary grouting reinforcement, thereby improving the stability of the underground structure. The project is of great significance and has significant social and economic benefits.

[0033] Among them, the early grouting not only plays a role in strengthening the stratum, but more importantly, the grouting at this time can strengthen the soil around the pile, making the connection between the soil around the pile and the pile foundation more stable and tight. Because after the shield cuts the pile foundation, the remaining pile ends have no support, and the pile ends lose the bearing capacity. More force is transferred to the connection between the pile and the soil around the pile. It relies on the friction resistance between the pile and the soil around the pile. If the soil around the pile is not reinforced in advance, relying only on the original pile side friction resistance may cause greater settlement.

[0034] The above embodiments are only exemplary embodiments of the present application and are not intended to limit the present application. The protection scope of the present application is defined by the claims. Those skilled in the art may make various modifications or equivalent substitutions to the present application within the essence and protection scope of the present application, and such modifications or equivalent substitutions shall also be deemed to fall within the protection scope of the present application.

Claims

1. A method for controlling station deformation caused by shield tunneling through pile foundations, characterized by the following steps: Step 1: before shield excavation, grouting is performed to reinforce the surrounding soil (1) and the soil (1) between the piles at the bottom of the station body (11) to be penetrated by the pile foundation (2); Step 2: before the shield machine penetrates the pile foundation (2), a settlement monitoring system is installed at the station to dynamically monitor and feedback the settlement deformation of the station during the process of the shield machine penetrating the pile foundation (2); Step 3: The shield machine (7) excavates the tunnel underground, gradually advancing to remove part of the pile foundation (2) and the soil between the piles (1), while removing the residue at the rear; Step 4: Inject grouting material into the underground structure through the grouting pipe (5) in front of the excavation of the shield machine (7) to fill the gaps and cracks in the soil layer to form a reinforcement curtain; Step 5: After the shield machine (7) advances a certain distance, the segments (4) behind the shield body of the shield machine (7) begin to be spliced ​​to form the basic structure of the assembled prefabricated pipeline (12); Step six, after the segment (4) is spliced, grouting is immediately performed at the shield tail. When the shield segment (4) of the shield machine (7) is separated from the shield tail, grouting is performed synchronously at the shield tail of the shield machine (7) to timely fill the building gap between the shield body of the shield machine (7) and the lining structure.

2. A method for controlling station deformation caused by shield tunneling through pile foundations according to claim 1, characterized in that: In the step 1, before the shield excavation, the grouting pipe (5) is buried around the station body (11), and the grouting pipe (5) is inserted into the soil (1) in an oblique manner, until the end of the grouting pipe (5) reaches the area to be reinforced. After the reinforcement is completed, the grouting pipe (5) is completely pulled out and filled with filling material.

3. A method for controlling station deformation caused by shield tunneling through pile foundations according to claim 2, characterized in that: The grouting pipe (5) is a rigid sleeve valve pipe, and the grouting pipe (5) penetrates into the surrounding soil (1) from a supplementary grouting pipeline (8) reserved in the pipe segment (4).

4. A method for controlling station deformation caused by shield tunneling through pile foundations according to claim 2, characterized in that: In step 1, the grouting process for reinforcing the pile foundation (2) is as follows: The first step is to evaluate the soil mass (1) around the pile above the tunnel (3) to be excavated and select appropriate grouting materials according to the specific ground conditions; The second step is to bury the grouting pipe (5) and use professional grouting equipment to inject slurry into the stratum to be reinforced so that the slurry can fully fill the gaps in the soil layer; The third step, after the grouting is completed, is to carry out post-processing work, clean up the excess slurry and repair the construction traces, and finally carry out testing and evaluation work.

5. The method for controlling station deformation caused by shield tunneling through pile foundation according to claim 1, characterized in that: In the step 2, during the shield tunneling through the pile foundation (2), the station settlement is dynamically monitored in real time to obtain timely feedback of the results; If the monitored deformation and settlement of the station is within the allowable range, shield excavation work will continue; if the monitored settlement is too large and exceeds the warning value or the station has uneven settlement, shield excavation work will be stopped immediately, and additional grouting will be carried out to control the problem of excessive settlement or uneven settlement of the station, and shield excavation construction will be continued after the monitored settlement returns to normal.

6. The method for controlling station deformation caused by shield tunneling through pile foundation according to claim 1, characterized in that: In step 4, the diameter of the cutter head (9) is greater than the outer diameter of the pipe segment (4), and a gap (10) is provided between the outside of the pipe segment (4) and the soil (1).

7. A method for controlling station deformation caused by shield tunneling through pile foundations according to claim 6, characterized in that: In step five, the pipe segments (4) are prefabricated pipe segments, and the pipe segments (4) are fixed by bolts when being spliced.

8. The method for controlling station deformation caused by shield tunneling through pile foundation according to claim 1, characterized in that: In step six, the shield machine (7) transports the slurry to the gap between the shield tunnel (6) and the surrounding soil (1). Before the slurry is completely solidified, the assembled prefabricated pipe (12) is located in the shield tunnel (6). Only after the slurry is solidified, the assembled prefabricated pipe (12) is connected to the surrounding soil (1) and the end of the residual pile.

9. The method for controlling station deformation caused by shield tunneling through pile foundation according to claim 1, characterized in that: In step 4, the grouting reinforcement needs to be synchronously controlled with the shield excavation, and the advancing speed of the shield machine (7) and the injection speed of the grouting material should be kept consistent.

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