Unconsolidated formation underneath pass civil house warehouse pressure stabilizing method

Abstract

The invention discloses a method for stabilizing warehouse pressure of an unconsolidated formation passing through a civil house under the unconsolidated formation. Relates to the technical field of shield method construction. 2, advanced grouting reinforcement is conducted in the hole; thirdly, radial hole grouting is conducted; 4, synchronous grouting is conducted; and fifthly, secondary grouting is conducted. According to the method, under the conditions that the shield penetrates through the house in the unconsolidated stratum and the ground grouting reinforcement condition is poor, grouting reinforcement is effectively conducted on the stratum, the purpose of stabilizing the bin pressure is achieved, the construction risk of penetrating through the house is reduced, and therefore the shield penetrates through the house safely and smoothly.

Description

Technical Field

[0001] The invention relates to the technical field of shield construction, and more particularly to a storage pressure stabilization method for passing through residential buildings under loose strata. Background Art

[0002] With the rapid development of cities, ground buildings have become taller and denser. To meet people's daily travel needs, more and more subways and intercity railways have been added. Shield tunneling is usually used for construction, which will cause the shield tunnel and ground buildings to overlap in space. How to ensure the safety and stability of the house when the shield tunnel passes under the house is the primary construction goal. When passing under the house in loose strata, the stratum loses a lot of air, the soil is easy to peel off, and the construction safety risk is extremely high.

[0003] Therefore, how to provide a method for stabilizing the chamber pressure when the shield machine passes through a building in loose strata, so as to keep the chamber pressure stable and pass through the house safely and smoothly, is an urgent problem that technicians in this field need to solve. Summary of the invention

[0004] In view of this, the present invention provides a method for stabilizing chamber pressure when passing through residential buildings in loose strata, aiming to solve one of the problems in the above-mentioned background technology. When the shield machine passes through a building in loose strata, the chamber pressure can be kept stable, so as to pass through the house safely and smoothly.

[0005] In order to achieve the above object, the present invention adopts the following technical solution:

[0006] A method for stabilizing loose strata underpasses residential buildings by pressure stabilization, comprising:

[0007] Step 1: Stop and maintain pressure

[0008] Before the shield machine reaches the house, it is stopped to maintain pressure, and the soil bin, shield body and shield tail are filled with bentonite;

[0009] Step 2: Pre-grouting reinforcement in the tunnel

[0010] Use advance grouting in the tunnel to reinforce the loose strata under the house. Use the advance grouting hole on the top of the shield machine and use the drilling and grouting machine to reinforce the soil in front of the cutterhead. After the shield machine has excavated the reinforcement range, immediately carry out the next cycle of advance grouting reinforcement in the tunnel until the shield machine successfully passes through the house.

[0011] Step 3: Radial hole grouting

[0012] During the excavation process, the radial holes of the middle shield are used to fill the gap between the shield body and the formation with grouting to block the leakage channel at the formation position of the middle shield. Chemical slurry is used as slurry.

[0013] Step 4: Synchronous grouting

[0014] Increase the amount of synchronous grouting to ensure sufficient synchronous grouting, shorten the grouting time, and fill the gap between the pipe segment and the formation in time to prevent formation collapse;

[0015] Step 5: Secondary Grouting

[0016] After the segment is out of the shield tail 3-5, secondary grouting is immediately carried out and a water stop ring is applied to fill the gap between the stratum and the segment densely and to block the water and air leakage channels behind the segment.

[0017] Furthermore, in step 1, the pressure maintaining pressure in the soil bin is 0.2-0.3 bar greater than that during normal excavation.

[0018] Furthermore, the reinforcement range of the grouting reinforcement in step 2 is 6-8m in front of the cutter head.

[0019] Furthermore, high viscosity bentonite or clay is used in step three.

[0020] Furthermore, in step five, the grouting pressure is controlled within 0.4 MPa.

[0021] It can be seen from the above technical scheme that compared with the prior art, the present invention discloses a method for stabilizing the storage pressure when passing through residential houses in loose strata, which solves the problem that when the shield passes through houses in loose strata and the ground grouting reinforcement conditions are poor, the strata can be effectively grouting reinforced, and the purpose of stabilizing the storage pressure can be achieved, thereby reducing the construction risk of passing through houses, thereby allowing the shield to pass through houses safely and smoothly. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying creative work.

[0023] Figure 1 A construction process flow chart provided by the present invention;

[0024] Figure 2 A flow chart of the in-hole advance grouting construction process provided by the present invention;

[0025] Figure 3 A schematic diagram of the overall construction scheme provided by the present invention;

[0026] Figure 4 This is a radial hole grouting hole arrangement diagram provided by the present invention. DETAILED DESCRIPTION

[0027] 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.

[0028] See also Figure 1-4 The embodiment of the present invention discloses a method for stabilizing the pressure of a loose stratum under a residential building, comprising:

[0029] Step 1: Stop and maintain pressure

[0030] Before the shield machine reaches the house, it is stopped to maintain pressure, and the soil bin, shield body and shield tail are filled with bentonite; before the shield machine reaches the loose stratum under the house, bentonite is used to maintain pressure, and the air pressure auxiliary mode is turned off to maintain pressure, and the bin, shield body and shield tail are filled with bentonite. The pressure maintenance pressure is well controlled. When the bin pressure drops, bentonite is injected into the soil bin in time to keep the soil bin pressure stable;

[0031] Step 2: Pre-grouting reinforcement in the tunnel

[0032] Use advance grouting in the tunnel to reinforce the loose stratum under the house. Use the advance grouting hole on the top of the shield machine and the drilling and grouting machine to reinforce the soil in front of the cutter head. After the shield machine has excavated the reinforcement range, immediately carry out the next cycle of advance grouting in the tunnel until the shield machine successfully passes through the house. The advance reinforcement adopts backward grouting, phosphoric acid sealing, double liquid slurry to reinforce the stratum, water-cement ratio of 1:1, drilling depth of 16 meters, and 3 advance grouting holes on the upper part of the shield machine. Two of them are selected for grouting. The grouting is controlled by the soil bin pressure and the grouting machine pressure. The grouting pressure shall not be higher than 2MPa, and the soil bin pressure shall not be higher than the shutdown pressure maintenance pressure of more than 1bar. After the soil bin pressure reaches the control pressure, the cutter head is immediately rotated to discharge the bin and reduce the pressure, and the drill rod is retreated;

[0033] Step 3: Radial hole grouting

[0034] During the excavation process, the radial holes of the middle shield are used to grout the gaps between the shield body and the formation to block the air leakage channel at the middle shield formation position. Chemical slurry is used as the slurry. During the excavation process, chemical slurry (water glass + phosphoric acid AB mixture) is injected through the radial holes of the middle shield, which can effectively stabilize the excavation chamber pressure and fill the outer cavity of the shield body in time to block the air leakage channel at the middle shield formation position. The chemical slurry is in a colloidal state at the initial stage of fusion, which can be stacked and penetrated into the formation to effectively fill the formation pores. In the later stage, it is in a crystalline state with a certain self-stabilizing ability, and can be replaced by high-viscosity bentonite or clay effect.

[0035] Step 4: Synchronous grouting

[0036] Increase the grouting volume of synchronous grouting to ensure sufficient synchronous grouting, shorten the grouting setting time, and fill the gap between the pipe segment and the formation in time to prevent formation collapse; during the crossing, the quality of each ring of grout should be strictly checked. On the premise that the amount of each ring is sufficient, the grouting cement ratio and viscosity should be appropriately adjusted to reduce the synchronous grouting setting time;

[0037] Step 5: Secondary Grouting

[0038] After the segment comes out of the shield tail 3-5, secondary grouting is immediately carried out, and a water stop ring is applied to fill the gap between the stratum and the segment densely, and to block the water and air leakage channels behind the segment; while the shield machine passes under the house, secondary grouting is carried out at the position of 3-5 rings out of the shield tail using the reserved grouting holes on the ground grouting backstage and the segment in the tunnel. Open hole grouting is carried out every other ring. The grouting points are selected at the upper points, and the slurry uses cement + water glass double liquid slurry.

[0039] In this embodiment, the pressure maintaining pressure in the soil bin in step 1 is 0.2-0.3 bar greater than that during normal excavation.

[0040] In this embodiment, the reinforcement range of the grouting reinforcement in step 2 is 6-8m in front of the cutter head.

[0041] In this embodiment, high viscosity bentonite or clay is used in step three.

[0042] In this embodiment, the grouting pressure in step five is controlled within 0.4 MPa.

[0043] In this specification, each embodiment is described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the embodiments can be referred to each other. For the device disclosed in the embodiment, since it corresponds to the method disclosed in the embodiment, the description is relatively simple, and the relevant parts can be referred to the method part.

[0044] The above description of the disclosed embodiments enables one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for stabilizing loose strata underpasses residential buildings, characterized in that: The following steps are involved: Step 1: Stop and maintain pressure Before the shield machine reaches the house, it is stopped to maintain pressure, and the soil bin, shield body and shield tail are filled with bentonite; Step 2: Pre-grouting reinforcement in the tunnel Use advance grouting in the tunnel to reinforce the loose strata under the house. Use the advance grouting hole on the top of the shield machine and use the drilling and grouting machine to reinforce the soil in front of the cutterhead. After the shield machine has excavated the reinforcement range, immediately carry out the next cycle of advance grouting reinforcement in the tunnel until the shield machine successfully passes through the house. Step 3: Radial hole grouting During the excavation process, the radial holes of the middle shield are used to fill the gap between the shield body and the formation with grouting to block the leakage channel at the formation position of the middle shield. Chemical slurry is used as slurry. Step 4: Synchronous grouting Increase the amount of synchronous grouting to ensure sufficient synchronous grouting, shorten the grouting time, and fill the gap between the pipe segment and the formation in time to prevent formation collapse; Step 5: Secondary Grouting After the segment is out of the shield tail 3-5, secondary grouting is immediately carried out and a water stop ring is applied to fill the gap between the stratum and the segment densely and to block the water and air leakage channels behind the segment.

2. A method for stabilizing the loose strata under the residential buildings according to claim 1, characterized in that: In step 1, the pressure in the soil bin is 0.2-0.3 bar greater than that during normal excavation.

3. The method for stabilizing the loose strata under the residential buildings according to claim 1 is characterized in that: The reinforcement range of grouting reinforcement in step 2 is 6-8m in front of the cutter head.

4. The method for stabilizing the loose strata under the residential buildings according to claim 1 is characterized in that: In step three, high viscosity bentonite or clay is used.

5. The method for stabilizing the loose strata under the residential buildings according to claim 1 is characterized in that: In step five, the grouting pressure is controlled within 0.4Mpa.

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