A tunnel construction method

Abstract

A tunnel construction method includes the following steps: (S1) setting up a pipe jacking machine along an axis parallel to the adjacent tunnel for pipe jacking operation; (S2) detecting the offset and offset angle of the front end of the pipe jacking machine in real time; (S3) calculating the offset after jacking the next pipe section based on the detected offset and offset angle of the front end of the pipe jacking machine; (S4) suspending the pipe jacking operation when the offset after jacking the next pipe section exceeds the limiting standard of the jacking operation; (S5) driving multiple water-jet grouting piles between the front end of the pipe jacking machine and the adjacent tunnel; (S6) adjusting the front end of the pipe jacking machine; (S7) continuing the pipe jacking operation; (S8) cyclically implementing steps (S2) and (S7) until the pipe jacking operation is completed; the present invention drives multiple water-jet grouting piles between the pipe jacking machine and the adjacent tunnel, making the geological hardness around the pipe jacking machine more uniform, thereby allowing the pipe jacking machine to easily adjust the position and orientation of its front end.

Description

Technical Field

[0001] This invention relates to the field of tunnel construction technology, and in particular to a tunnel construction method. Background Technology

[0002] Currently, during the construction of the main structure of subway stations, due to external factors such as pipelines and existing buildings, the pipe jacking method is usually used when constructing tunnels for the platform level and track area. Two tunnels, the left and right lines, must be constructed separately. Since the two pipe jacking tunnels are very close together, the later-constructed tunnel is significantly affected by the earlier-constructed one. Specifically, during the construction of the pipe jacking tunnel, drag-reducing mud is injected into the tunnel wall to lubricate the pipe sections. After the jacking is completed, the fluid drag-reducing mud must be replaced with permanently solidified cement grout to stabilize the tunnel. After the earlier-constructed tunnel undergoes the replacement process with thixotropic mud, the cement grout diffuses into the surrounding strata, providing some ground reinforcement. When constructing the second tunnel, if the pipe jacking machine encounters strata with uneven hardness, the front end of the machine is prone to significant positional and directional deviations. Because the strata on one side are harder, and the pipe jacking machine has poor rock-breaking ability, it is difficult to correct the deviation using its active articulation and jacks. Summary of the Invention

[0003] The purpose of this invention is to provide a tunnel construction method to solve the technical problem that, in the construction of double-line close-fitting pipe jacking tunnels, it is difficult to correct the deviation of the front end of the pipe jacking machine after it has shifted during the subsequent tunnel construction.

[0004] To achieve the above objectives, the present invention provides a tunnel construction method, comprising the following steps: (S1) The pipe jacking machine is set up along the axis parallel to the adjacent tunnel, and the pipe jacking machine is used to carry out pipe jacking operations; (S2) Real-time detection of the offset and offset angle of the front end of the pipe jacking machine; (S3) Calculate the offset after jacking the next pipe section based on the detected offset and offset angle of the front end of the pipe jacking machine; (S4) When the offset after jacking the next pipe section exceeds the limit standard for jacking operation, jacking operation shall be suspended; (S5) Drive multiple jet grouting piles between the front end of the pipe jacking machine and the adjacent tunnel to soften the strata between the front end of the pipe jacking machine and the adjacent tunnel. (S6) Adjust the position and / or orientation of the front end of the pipe jacking machine; (S7) Continue the pipe jacking operation; (S8) Repeat steps (S2) and (S7) in sequence until the pipe jacking operation is completed.

[0005] Optionally, the following steps may also be included: After step (S5), the pile hole of the jet grouting pile is sealed with cement grout.

[0006] Optionally, in step (S5), each jet grouting pile is not positioned before the front end of the pipe jacking machine.

[0007] Optionally, in step (S4), the limiting standard for the jacking operation is that the offset of the front end of the pipe jacking machine does not exceed 50 mm in the vertical direction and 80 mm in the horizontal direction.

[0008] Optionally, in step (S5), each jet grouting pile is arranged parallel to the axial direction of the pipe jacking operation, with 8 to 10 jet grouting piles, a spacing of 400 mm to 500 mm between adjacent jet grouting piles, and a diameter of 550 mm to 650 mm.

[0009] Optionally, in step (S5), the depth of the jet grouting pile is 15m to 20m, the jet grouting depth is 5m to 10m, the vertical deviation of the jet grouting pile does not exceed 1%, and the positional deviation of the jet grouting pile does not exceed 20mm.

[0010] Optionally, the distance between the inner wall of the tunnel generated by the pipe jacking operation in step (S1) and the inner wall of the adjacent tunnel is 1.4m to 1.6m.

[0011] Optionally, in step (S1), during the pipe jacking operation, the pressure of the slurry chamber of the pipe jacking machine is 150 kPa to 160 kPa.

[0012] Optionally, the pipe jacking machine includes a jacking jack device; Among them, the number of jacks used for correction in the direction of adjacent tunnels is greater than the number of jacks used for correction in the direction away from adjacent tunnels.

[0013] Optionally, the following steps may also be included: In step (S1), while the pipe jacking machine is performing pipe jacking operations, it injects drag-reducing mud into the tunnel wall. The amount of drag-reducing mud injected away from the adjacent tunnel is greater than the amount of drag-reducing mud injected towards the adjacent tunnel.

[0014] Compared with the prior art, the tunnel construction method of this invention has the following advantages: This invention detects the offset and orientation of the front end of the pipe jacking machine during the pipe jacking operation. When the offset and / or offset angle is too large, causing the pipe section to exceed the limit standard during subsequent pipe jacking operations, multiple jet grouting piles are driven between the pipe jacking machine and the adjacent tunnel to soften the geology in that area, making the geology hardness around the pipe jacking machine more uniform, thereby allowing the pipe jacking machine to easily adjust the position and orientation of its front end. Attached Figure Description

[0015] Figure 1 This is a top view of the front end of the pipe jacking machine of the present invention.

[0016] Figure 2 This is a cross-sectional view of the tunnels and jet grouting piles on both sides of the present invention.

[0017] Attached reference numerals: 1. Pipe jacking machine; 2. Jet grouting pile; 3. Pipe section. Detailed Implementation

[0018] The specific embodiments of the present invention will be described in further detail below with reference to the accompanying drawings and examples. The following examples are for illustrative purposes only and are not intended to limit the scope of the invention.

[0019] In the description of this invention, it should be understood that the terms "top", "bottom", "inner", "outer", "circumferential", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention.

[0020] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0021] like Figure 1 and 2 As shown, a tunnel construction method of the present invention includes the following steps: (S1) setting the pipe jacking machine 1 along the axial direction parallel to the adjacent tunnel and using the pipe jacking machine 1 to perform pipe jacking operations; (S2) detecting the offset and offset angle of the front end of the pipe jacking machine 1 in real time; (S3) calculating the offset after jacking the next pipe section 3 based on the detected offset and offset angle of the front end of the pipe jacking machine 1; (S4) suspending the pipe jacking operation when the offset after jacking the next pipe section 3 is greater than the limiting standard of the jacking operation; (S5) driving multiple jet grouting piles 2 for water spraying between the front end of the pipe jacking machine 1 and the adjacent tunnel to soften the strata between the front end of the pipe jacking machine 1 and the adjacent tunnel; (S6) adjusting the position and / or orientation of the front end of the pipe jacking machine 1; (S7) continuing the pipe jacking operation; (S8) cyclically implementing steps (S2) and (S7) until the pipe jacking operation is completed.

[0022] In the above technical solution, the jet grouting pile 2 is an empty pile, only sprayed with water, used to soften the soil between the front end of the pipe jacking machine 1 and the adjacent tunnel, in order to improve the situation where the difference in geological hardness on both sides of the pipe jacking machine 1 makes it difficult for the pipe jacking machine 1 to correct its deviation. Generally, the bottom of any jet grouting pile 2 is lower than the bottom of the tunnel. The jet grouting range of the jet grouting pile 2 in the vertical direction includes at least from the bottom to the top of the tunnel to ensure that enough soil is softened. In addition, the offset amount after advancing one pipe section thickness along the current offset angle plus the current offset amount can be used to obtain the offset amount after jacking the next pipe section 3. The offset amount in the vertical direction and the offset amount in the horizontal direction are calculated and judged separately. In the limiting standard, the allowable offset amount in the horizontal direction is greater than the allowable offset amount in the vertical direction. In addition, the front end of the pipe jacking machine 1 is specifically a cutterhead, used for breaking the soil.

[0023] Furthermore, since all jet grouting piles 2 are empty piles, the construction method also includes the following steps: after step (S5), the pile holes of jet grouting piles 2 are sealed with cement grout. Specifically, all pile holes can be sealed at once after the pipe jacking operation is completed.

[0024] Furthermore, since the face of the cutterhead at the front end of the pipe jacking machine 1 must maintain water and soil pressure through slurry balance, if the front end of the pipe jacking machine 1 is behind the jet grouting pile 2, a pressure transmission channel will be formed from the face to the ground, causing the slurry pressure at the face to be transmitted to the ground, which will result in a decrease in the slurry pressure at the face and lead to soil settlement. Therefore, in step (S5), each jet grouting pile 2 is not ahead of the front end of the pipe jacking machine 1, which can also reduce the tendency of the pipe jacking machine 1 to deviate horizontally and facilitate the correction operation.

[0025] Furthermore, in step (S4), the limiting standard for the jacking operation is that the offset of the front end of the pipe jacking machine 1 does not exceed 50mm in the vertical direction and 80mm in the horizontal direction.

[0026] Furthermore, in step (S5), each jet grouting pile 2 is spaced parallel to the axial direction of the pipe jacking operation to ensure the continuity of the softened geological conditions. Furthermore, in order to ensure the softening effect and allow the pipe jacking machine 1 to smoothly adjust the position and orientation of its front end, in step (S5), the number of jet grouting piles 2 is 8 to 10, preferably 9, the spacing between adjacent jet grouting piles 2 is 400mm to 500mm, preferably 450mm, and the diameter of the jet grouting pile 2 is 550mm to 650mm, preferably 600mm.

[0027] Furthermore, in step (S5), the depth of the jet grouting pile 2 is 15m to 20m, preferably 17.5m, and the jet grouting depth is 5m to 10m, preferably 7.5m, to cope with the general tunnel depth in the construction of double-line close-fitting pipe jacking tunnel. In order to adapt to the depth of the jet grouting pile 2 and prevent the jet grouting pile 2 from being misaligned, the vertical deviation of the jet grouting pile 2 shall not exceed 1%, and the positional deviation of the jet grouting pile 2 shall not exceed 20mm.

[0028] Furthermore, in step (S1), the distance between the inner wall of the tunnel generated by the pipe jacking operation and the inner wall of the adjacent tunnel is 1.4m to 1.6m. In the construction of double-line close-fitting pipe jacking tunnels, this value is generally 1.5m.

[0029] Furthermore, in order to reduce the impact on the correction cylinder and reduce the pressure of the land on the side of the pipe section 3 near the adjacent tunnel, in step (S1), during the pipe jacking operation, the pressure of the slurry chamber of the pipe jacking machine 1 is 150 kPa to 160 kPa, preferably 155 kPa.

[0030] Furthermore, the pipe jacking machine includes a jacking jacking device; wherein, the geological conditions between the pipe jacking machine 1 and the adjacent tunnel are relatively hard, and the pipe jacking machine 1 is prone to deviating in a direction away from the adjacent tunnel. To facilitate the correction of the pipe jacking machine 1, the number of jacks used for correction in the direction of the adjacent tunnel is greater than the number of jacks used for correction in the direction away from the adjacent tunnel, thereby increasing the correction force in the direction of the adjacent tunnel. Specifically, when the adjacent tunnel is to the right of the pipe jacking machine 1, the number of jacks located on its left side in the jacking jacking device is greater than the number of jacks located on its right side. The jacking jack device has 7 jacks on the left side and 4 jacks on the right side. In addition, the pipe jacking machine 1 also includes an active hinge structure, which is the main correction device and the jacking jack device is the auxiliary correction device. Furthermore, due to gravity, the pipe jacking machine 1 tends to deflect downwards in most cases. The number of jacks on the lower side of the jacking jack device is greater than the number of jacks on the upper side. Specifically, the number of jacks on the lower side of the jacking jack device is 12, and the number of jacks on the upper side of the jacking jack device is 3.

[0031] Furthermore, the following steps are also included: In step (S1), while the pipe jacking machine 1 is performing pipe jacking operations, the pipe jacking machine 1 injects drag-reducing mud into the tunnel wall. The drag-reducing mud serves to lubricate and bear pressure, so as to facilitate the jacking of the pipe jacking machine and the movement of the pipe sections. The drag-reducing mud is thixotropic mud. The geological conditions between the pipe jacking machine 1 and the adjacent tunnel are relatively hard, and the pipe jacking machine 1 is prone to deviating in the direction away from the adjacent tunnel. In order to reduce the damage to the geological conditions in the direction away from the adjacent tunnel when the pipe jacking machine 1 is corrected, the amount of drag-reducing mud injected in the direction away from the adjacent tunnel is greater than the amount of drag-reducing mud injected in the direction towards the adjacent tunnel.

[0032] Furthermore, after step (S5), the drag-reducing mud in the tunnel wall is replaced with cement slurry to reinforce the geology around the tunnel. Specifically, this can be achieved by extracting the drag-reducing mud and then injecting cement slurry for replacement.

[0033] In summary, the embodiments of the present invention provide a tunnel construction method, the technical effects of which are as follows: This invention detects the offset and orientation of the front end of the pipe jacking machine during the pipe jacking operation. When the offset and / or offset angle is large, causing the pipe section to exceed the limit standard during subsequent pipe jacking operations, multiple jet grouting piles without cement and only sprayed with water are driven between the pipe jacking machine and the adjacent tunnel to soften the geology in that area, making the geological hardness around the pipe jacking machine more uniform, thereby allowing the pipe jacking machine to easily adjust the position and orientation of its front end.

[0034] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and substitutions can be made without departing from the technical principles of the present invention, and these improvements and substitutions should also be considered within the scope of protection of the present invention.

Claims

1. A tunnel construction method, characterized in that, Includes the following steps: (S1) The pipe jacking machine is set up along the axis parallel to the adjacent tunnel, and the pipe jacking machine is used to carry out pipe jacking operation. At the same time as the pipe jacking machine is carrying out pipe jacking operation, the pipe jacking machine injects drag-reducing mud into the tunnel wall. The amount of drag-reducing mud injected away from the adjacent tunnel is greater than the amount of drag-reducing mud injected towards the adjacent tunnel. The pipe jacking machine includes a jacking jack device. The number of jacks used for correction towards the adjacent tunnel is greater than the number of jacks used for correction away from the adjacent tunnel. (S2) Real-time detection of the offset and offset angle of the front end of the pipe jacking machine; (S3) Calculate the offset after jacking the next pipe section based on the detected offset and offset angle of the front end of the pipe jacking machine; (S4) When the offset after jacking the next pipe section exceeds the limit standard for jacking operation, jacking operation shall be suspended; (S5) Drive multiple jet grouting piles between the front end of the pipe jacking machine and the adjacent tunnel to soften the strata between the front end of the pipe jacking machine and the adjacent tunnel. The depth of the jet grouting piles is 15m to 20m, the jet grouting depth is 5m to 10m, the vertical deviation of the jet grouting piles does not exceed 1%, and the positional deviation of the jet grouting piles does not exceed 20mm. (S6) Adjust the position and / or orientation of the front end of the pipe jacking machine; (S7) Continue the pipe jacking operation; (S8) Repeat steps (S2) and (S7) in sequence until the pipe jacking operation is completed.

2. The tunnel construction method according to claim 1, characterized in that, It also includes the following steps: After step (S5), the pile hole of the jet grouting pile is sealed with cement grout.

3. The tunnel construction method according to claim 1, characterized in that, In step (S5), each jet grouting pile is not positioned before the front end of the pipe jacking machine.

4. The tunnel construction method according to claim 1, characterized in that, In step (S4), the limiting standard for jacking operation is that the offset of the front end of the pipe jacking machine shall not exceed 50 mm in the vertical direction and 80 mm in the horizontal direction.

5. The tunnel construction method according to claim 1, characterized in that, In step (S5), each jet grouting pile is spaced parallel to the axial direction of the pipe jacking operation. The number of jet grouting piles is 8 to 10, the spacing between adjacent jet grouting piles is 400 mm to 500 mm, and the diameter of the jet grouting pile is 550 mm to 650 mm.

6. The tunnel construction method according to claim 1, characterized in that, In step (S1), the distance between the inner wall of the tunnel generated by the pipe jacking operation and the inner wall of the adjacent tunnel is 1.4m to 1.6m.

7. The tunnel construction method according to claim 1, characterized in that, In step (S1), during the pipe jacking operation, the pressure of the slurry chamber of the pipe jacking machine is 150 kPa to 160 kPa.

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