A construction method for preventing shield receiving formed segments from loosening

Abstract

A shield receiving formed pipe segment anti-loosening construction method, the steps are as follows: installing and fixing the shield receiving bracket, and controlling the excavation direction of the shield machine; when the shield machine cutter head contacts the retaining wall, installing a check valve in the shield tail pipe segment opening to inject double liquid slurry, and injecting double liquid slurry through the radial hole of the shield front shield at the same time; when the shield machine starts to grind pile excavation, reducing the soil bin pressure, and synchronously injecting double liquid slurry behind the wall; when the radial hole of the shield front shield reaches the main structure, the front shield and the main structure form a closed space, and then injecting double liquid slurry through the radial hole of the front shield, and stopping the machine after the grouting is completed until the slurry strength is reached; when the shield tail reaches the main structure, the synchronous wall injection of double liquid slurry continues to be injected, and stopping the machine after the grouting is completed until the slurry strength is reached. The method is simple to operate, safe and reliable, can prevent the pipe segment from loosening, ensure the quality of the formed pipe segment, and enhance the sealing and waterproof effect of the receiving section of the shield machine.

Description

Technical Field

[0001] The invention relates to the technical field of shield construction, and in particular to a shield receiving formed pipe segment anti-loosening construction method. Background Art

[0002] Conventional shield receiving segment anti-loosening construction technology: Before the shield machine is received, the shield machine is first stopped, and then a manual assisted method is used to tighten, adjust and fix the steel sections and the formed segments during reception in the tunnel. This method has many control influencing factors, and the tightening, adjustment and fixing effect of the fixed segments is poor. The construction time is long, the construction cost is high, and it is not conducive to the effective control of the safe reception of the shield. Summary of the invention

[0003] In order to solve the above technical problems, the present invention provides a shield receiving formed pipe segment anti-loosening construction method, which is simple to operate, safe and reliable, can prevent the pipe segment from loosening, ensure the quality of the formed pipe segment, and enhance the sealing and waterproof effect of the shield machine receiving section.

[0004] In order to achieve the above object, the technical solution adopted by the present invention is:

[0005] A shield receiving formed segment anti-loosening construction method is provided, comprising the following steps:

[0006] 1. Install and fix the shield receiving bracket, and control the shield machine's excavation direction according to the measured data of the tunnel portal;

[0007] 2. When the cutterhead of the shield machine contacts the retaining wall and after the segment assembly is completed, the tail segment of the shield is removed and a hole is opened on the segment. A check valve is installed at the hole position to inject double liquid slurry. At the same time, double liquid slurry is injected through the radial holes of the front shield of the shield machine. After the grouting is completed, the machine is stopped until the slurry strength is reached;

[0008] 3. The shield machine continues to excavate. When the shield machine starts to grind piles, the soil bin pressure is reduced and double liquid slurry is injected behind the wall simultaneously;

[0009] 4. When the radial hole of the front shield of the shield machine reaches the main structure, the curtain plate is tightened to form a closed space between the front shield and the main structure, and then the double liquid slurry is injected through the radial hole of the front shield. After the grouting is completed, the machine is stopped until the slurry strength is reached;

[0010] 5. The shield machine continues to advance. When the shield tail reaches the main structure, the double-liquid slurry is injected continuously behind the synchronous wall. After the grouting is completed, the machine is shut down until the slurry strength is reached.

[0011] As a further improvement of the present invention, in step 1, before the shield machine reaches the tunnel gate, horizontal water exploration is carried out at the tunnel gate to check the water volume of the tunnel gate. The exploration holes are arranged as 9 The exploration hole should have a depth of 2.5 to 3.5 m and the water volume at the tunnel entrance should not exceed 20 L / h.

[0012] As a further improvement of the present invention, in step 2, holes are opened in the three-ring segments of the shield tail, and the opening positions are selected at 1 and 11 o'clock in the clock direction.

[0013] As a further improvement of the present invention, in step three, the tunneling speed of the shield machine is controlled within 10 mm / min, and the pressure of the double-liquid slurry injected behind the wall is controlled at 0.25 MPa.

[0014] As a further improvement of the present invention, in step five, after the grouting is completed, check whether the pipe segment meets the waterproofing requirements, open the check valve on the pipe segment, and observe the water stains. If there are no obvious water stains, the waterproofing requirements are met.

[0015] As a further improvement of the present invention, double-liquid grouting of the radial holes of the front shield of the shield machine is carried out in a bottom-up order.

[0016] As a further improvement of the present invention, the double liquid slurry adopts cement slurry PO 42.5R and water glass 40Be°, the ratio of cement slurry is cement: water = 1:0.8~1:1, and the ratio of water glass is water glass: water 1:1.

[0017] As a further improvement of the present invention, when injecting the double liquid slurry, the double liquid slurry pressure is controlled at 0.3-0.4Mpa, and the grouting is continued after the pressure stabilizes until the pressure rises, and then the grouting is completed by injecting for another 10-20 minutes.

[0018] As a further improvement of the present invention, the machine is shut down for at least 5 hours after the grouting is completed.

[0019] The beneficial effects of the present invention are as follows: the present method performs grouting through the radial holes of the front shield and the synchronous grouting system, so that the soil and slurry around the shield machine wrap the shield machine, increasing the friction between the shield body and the soil body. When the shield machine is pushed forward by the jack, the friction is used to increase the reaction force of the jack, so that the jack of the shield machine can press the pipe segment, making it difficult for the pipe segment to loosen, and cut off the water in the stratum, thereby ensuring the quality of the formed pipe segment and the sealing quality. The method does not require manual assistance such as tensioning, adjusting and fixing of steel sections, has high construction efficiency, short cycle, will not affect the interruption of excavation, and has the characteristics of convenient construction, simple operation, safety and reliability, less consumables and low cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is a schematic diagram of the cross section of the shield machine cutter head contacting the enclosure structure;

[0021] Figure 2 This is a cross-sectional diagram of the shield machine reaching the main structure;

[0022] Marking instructions: 1-shield machine, 11-front shield, 12-shield tail, 2-cutter disc, 3-front shield radial hole, 4-synchronous grouting pipe, 5-retaining wall structure, 6-main structure, 7-segment, 8-waterstop curtain plate, 9-check valve. DETAILED DESCRIPTION

[0023] The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments.

[0024] A shield receiving formed segment anti-loosening construction method comprises the following steps:

[0025] 1. Install and fix the shield receiving bracket. According to the measured data of the tunnel gate, control the excavation direction of the shield machine 1. In addition, before the shield machine 1 reaches the tunnel gate, conduct horizontal water exploration at the tunnel gate to check the water volume at the tunnel gate. The exploration holes are arranged as 9 The exploration hole should have a depth of 2.5 to 3.5 m and the water volume at the tunnel entrance should not exceed 20 L / h.

[0026] 2. If Figure 1 As shown, when the cutter head 2 of the shield machine 1 contacts the retaining wall structure 5, and after the segment 7 is assembled, the segment 7 at the shield tail 12 is removed and a hole is opened on the segment 7. The hole opening position is selected at the 1 and 11 o'clock positions in the clock direction. A check valve 9 is installed at the hole opening position to inject double liquid slurry. At the same time, the double liquid slurry is injected from bottom to top through the front shield radial holes 3 on the front shield 11 of the shield machine 1. After the grouting is completed, the machine is shut down for 5 hours to achieve the strength of the slurry, thereby increasing the friction between the slurry and the shield machine 1.

[0027] 3. Shield machine 1 continues to advance. When shield machine 1 starts to grind piles for excavation, the soil bin pressure is reduced, the excavation speed of shield machine 1 is controlled within 10 mm / min, and double-liquid slurry is injected behind the wall synchronously through synchronous grouting pipe 4. Grouting pressure control is mainly used. The double-liquid slurry pressure injected behind the wall is controlled at 0.25 Mbar to ensure that the rear part has greater friction during shield excavation.

[0028] 4. Figure 2 As shown in the figure, when the radial hole 3 of the front shield of the shield machine 1 reaches the main structure 6, the waterproof curtain plate 8 is tightened by fixing the wire rope with a hand winch, so that the front shield 11 and the main structure 6 form a closed space, and then the double liquid slurry is injected from bottom to top through the radial hole 3 of the front shield, and the injection volume is about 8.87m 3 After the grouting is completed, the machine is shut down for 5 hours to achieve the strength of the slurry. This step mainly uses the slurry to fill the gap between the main structure 6 and the retaining wall structure 5 to prevent water leakage in the mechanism and the formed tunnel, and also serves to enhance the friction between the front shield 11 of the shield machine 1 and the main structure 6 and the retaining wall structure 5.

[0029] 5. The shield machine 1 continues to advance. When the shield tail 12 reaches the main structure 6, the synchronous wall back injection of double liquid slurry is continuously performed through the synchronous grouting pipe 4. After the grouting is completed, the machine is shut down for 5 hours to reach the slurry strength. This step is mainly secondary grouting. After the grouting is completed, check whether the pipe segment 7 meets the waterproofing requirements, open the check valve 9 on the pipe segment 7, and observe the water stains. If there is no obvious water stain, the waterproofing requirements are met.

[0030] In the above steps, the double liquid slurry uses cement slurry PO 42.5R and water glass 40Be°, the ratio of cement slurry is cement: water = 1:0.8~1:1, and the ratio of water glass is water glass: water = 1:1. Grouting characteristics: The cohesion (c) and internal friction angle of the soil layer are The value increases, reduces its permeability, forms a relative waterproof layer, and ensures the sealing and waterproof quality of the receiving segment 7. When injecting double-liquid slurry, the double-liquid slurry pressure is controlled at 0.3-0.4Mpa. After the pressure stabilizes, continue to inject until the pressure rises, and then inject for another 10-20 minutes to complete the grouting.

[0031] After all the above steps are completed, the shield machine 1 can have sufficient reverse thrust to press the annular seams between the segments 7 tightly, and the waterproof requirement of the receiving section formed tunnel can be achieved without manual adjustment in the tunnel.

[0032] The above embodiments are only used to illustrate the present invention and are not intended to limit the present invention in any form. Any person with ordinary knowledge in the technical field may make partial changes or modifications to the technical contents disclosed in the present invention without departing from the scope of the technical features of the present invention, and the equivalent embodiments without departing from the technical features of the present invention are still within the scope of the technical features of the present invention.

Claims

1. A shield receiving formed segment anti-loosening construction method, characterized in that The following steps are involved:

1. Install and fix the shield receiving bracket, and control the shield machine's excavation direction according to the measured data of the tunnel portal; 2. When the cutterhead of the shield machine contacts the retaining wall and after the segment assembly is completed, the tail segment of the shield is removed and a hole is opened on the segment. A check valve is installed at the hole position to inject double liquid slurry. At the same time, double liquid slurry is injected through the radial holes of the front shield of the shield machine. After the grouting is completed, the machine is stopped until the slurry strength is reached; 3. The shield machine continues to excavate. When the shield machine starts to grind piles, the soil bin pressure is reduced and double liquid slurry is injected behind the wall simultaneously; 4. When the radial hole of the front shield of the shield machine reaches the main structure, the curtain plate is tightened to form a closed space between the front shield and the main structure, and then the double liquid slurry is injected through the radial hole of the front shield. After the grouting is completed, the machine is stopped until the slurry strength is reached; 5. The shield machine continues to advance. When the shield tail reaches the main structure, the double-liquid slurry is injected continuously behind the synchronous wall. After the grouting is completed, the machine is shut down until the slurry strength is reached.

2. A shield receiving formed segment anti-loosening construction method according to claim 1, characterized in that: In step one, before the shield machine reaches the tunnel portal, horizontal water exploration is carried out at the tunnel portal to check the water volume at the tunnel portal. The exploration holes are arranged in 9 holes with a hole depth of 2.5 to 3.5 m. The water volume at the tunnel portal shall not be higher than 20 L / h.

3. A shield receiving formed segment anti-loosening construction method according to claim 1, characterized in that: In step three, the shield machine excavation speed is controlled within 10mm / min, and the double liquid slurry pressure injected into the wall is controlled at 0.25Mpa.

4. A shield receiving formed segment anti-loosening construction method according to claim 1, characterized in that: In step five, after the grouting is completed, check whether the pipe segment meets the waterproofing requirements. Open the check valve on the pipe segment and observe the water stains. If there are no obvious water stains, the waterproofing requirements are met.

5. A shield receiving formed segment anti-loosening construction method according to claim 1, characterized in that: The double-liquid grouting of the radial holes of the front shield of the shield machine is carried out from bottom to top.

6. A shield receiving formed segment anti-loosening construction method according to claim 1, characterized in that: The double liquid slurry uses cement slurry PO 42.5R and water glass 40Be°. The ratio of cement slurry is cement: water = 1:0.8~1:1, and the ratio of water glass is water glass: water 1:

1.

7. A shield receiving formed segment anti-loosening construction method according to claim 6, characterized in that: When injecting double liquid slurry, the double liquid slurry pressure is controlled at 0.3-0.4Mpa. After the pressure stabilizes, grouting is continued until the pressure rises, and then injection is continued for 10-20 minutes to complete the grouting.

8. A shield receiving formed segment anti-loosening construction method according to claim 1, characterized in that: After the grouting is completed, the machine will be shut down for at least 5 hours.

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