Method for plugging portal of shield tunnel at starting point and plugging device for portal

Abstract

The present invention discloses a shield tunnel portal plugging device, which includes a portal steel ring installed on an inner lining wall, at least two sets of sealing components provided on the portal steel ring, and a plurality of grouting holes pre-buried in the portal steel ring and located between the at least two sets of sealing components. The sealing components are arranged around the circumference of the portal steel ring and at least two sets of sealing components are arranged along the axial direction of the portal steel ring. The plurality of grouting holes are arranged at intervals along the circumference of the portal steel ring. The plugging device of the present invention provides a plurality of grouting holes between the two sets of sealing components, and the plurality of grouting holes correspond to the clock positions of the portal steel ring, so that slurry can be injected from the clock positions of the upper part of the portal steel ring during plugging. The slurry injection is more uniform and the plugging effect is better. Compared with the provision of a membrane bag, it is simpler and more efficient. The plugging method based on the plugging device has simple steps, is easy to operate, can quickly fill the gap, and has a good plugging effect.

Description

[0001] This application is a divisional application of the invention patent application with the application date of July 31, 2020, application number 2020107579190, and name of the portal sealing device and sealing method for the start of a shield tunnel. Technical Field

[0002] The invention relates to the field of slurry shield, and in particular to a tunnel portal blocking method and a tunnel portal blocking device for a shield tunnel. Background Art

[0003] The shield tunneling start-up process is the first step in shield tunneling construction, and its construction quality directly affects the subsequent successful tunneling and breakthrough of the shield tunnel. During the shield tunneling start-up process, an annular gap exists between the portal and the shield shell. To prevent mud and water from entering the well through the annular gap during start-up, preventing the shield machine from effectively building pressure, a high-performance water-stop sealing device must be installed to ensure initial mud-water balance and guarantee construction safety in the start-up section.

[0004] However, existing water-stopping sealing devices typically use a membrane bag placed inside the tunnel steel ring and injecting slurry into the bag to expand it to achieve a sealing effect. However, the membrane bag is expensive and inconvenient to replace if damaged. Furthermore, the membrane bag and the tunnel steel ring cannot be tightly fitted, resulting in blind spots in the sealing. Summary of the Invention

[0005] An object of the present invention is to overcome the deficiencies of the prior art and provide an improved tunnel door blocking device.

[0006] In order to achieve the above object, the technical solution adopted by the present invention is:

[0007] A shield tunnel portal sealing device comprises a portal steel ring mounted on an inner lining wall, at least two sets of sealing assemblies provided on the portal steel ring, and a plurality of grouting holes pre-buried in the portal steel ring and located between the at least two sets of sealing assemblies. The sealing assemblies are arranged around the circumference of the portal steel ring and the at least two sets of sealing assemblies are arranged axially along the portal steel ring. The plurality of grouting holes are arranged at intervals along the circumference of the portal steel ring.

[0008] Preferably, the multiple grouting holes correspond one-to-one to the clock positions of the portal steel ring.

[0009] According to the present invention, the hour positions of the tunnel gate steel ring correspond one-to-one to the twelve hour positions on a clock.

[0010] According to the present invention, there are twelve grouting holes, and they are respectively arranged at the corresponding hour positions.

[0011] Preferably, a plurality of grouting channels are provided on the inner lining wall, and the plurality of grouting holes correspond to and are interconnected with the plurality of grouting channels one by one.

[0012] Preferably, the sealing assembly includes a rubber curtain cloth, circular ring plates and flap plates located on both sides of the rubber curtain cloth, and the rubber curtain cloth, the circular ring plates and the flap plates are fixedly connected to each other.

[0013] Preferably, the portal plugging device further includes at least one set of wire brushes provided on the portal steel ring, and the wire brushes are located in front of the sealing assembly.

[0014] Another object of the present invention is to provide a plugging method based on the above plugging device.

[0015] To achieve the above object, the technical solution adopted by the present invention is:

[0016] A plugging method for the portal of a shield tunnel at the start of tunneling, which includes the following steps:

[0017] (1) Preparation of slurry: Slowly and evenly add NSHS-1 slurry agent and NSHS-3 slurry agent into clear water. After they are fully dissolved, slowly add NSHS-2 slurry agent and stir evenly to obtain the slurry.

[0018] (2) Grouting before building the chamber: After the cutting ring of the shield machine completely enters the wire brush, synchronously inject slurry into the 11 o'clock position and 1 o'clock position of the portal steel ring. Stop grouting when the grouting pressure reaches the first set value. Wait for the slurry to completely flow into the cavity below the portal steel ring, and then synchronously inject slurry into the 9 o'clock position, 11 o'clock position, 1 o'clock position and 3 o'clock position of the portal steel ring. Stop grouting when the grouting pressure reaches the second set value; In this way, the slurry can completely flow into the cavity below the portal steel ring under the action of gravity and completely fill the lower cavity.

[0019] (3) Grouting during chamber building: When the liquid level of the heading face at the start of shield tunneling slowly rises, inject slurry into the 11 o'clock position to 8 o'clock position of the portal steel ring in a counterclockwise direction in sequence, then inject slurry into the 1 o'clock position to 4 o'clock position of the portal steel ring in a clockwise direction in sequence, and finally inject slurry into the 12 o'clock position of the portal steel ring. During the grouting process at each position, stop grouting when the grouting pressure reaches the third set value.

[0020] (4) Grouting during tunneling: During the tunneling process of the shield machine, observe the muddy water leakage situation of the portal steel ring, and according to the principle of proximity, inject slurry through the grouting hole on the portal steel ring closest to the muddy water leakage position for leak stoppage. Stop grouting when the muddy water leakage position no longer leaks.

[0021] Preferably, in the step (1), the mixing ratio of the NSHS-1 pulping agent, the NSHS-2 pulping agent, the NSHS-3 pulping agent and water is 1:4:1:20.

[0022] In a specific embodiment of the present invention, in the step (1), 50 kg of the NSHS-1 pulping agent and 50 kg of the NSHS-3 pulping agent are slowly and evenly added to 1 m³ of water. After being fully dissolved, 200 kg of the NSHS-2 pulping agent is slowly added and stirred evenly to obtain the slurry.

[0023] In a specific and preferred embodiment of the present invention, in the step (2), the first set value is 1 MPa, and the second set value is also 1 MPa.

[0024] In another specific and preferred embodiment of the present invention, in the step (3), the third set value is 1 MPa.

[0025] Due to the application of the above technical solutions, the present invention has the following advantages compared with the prior art: In the plugging device of the present invention, by arranging a plurality of grouting holes between two groups of sealing components, and the plurality of grouting holes corresponding to the hour positions of the portal steel ring, the slurry can be injected from the hour positions above the portal steel ring respectively during plugging, the slurry injection is more uniform and the plugging effect is better, which is simpler and more efficient than setting up a membrane bag; Based on the plugging method of this plugging device, the steps are simple, the operation is convenient, the gap can be quickly filled, and the leak stoppage effect is good. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Att Figure 1 is a radial cross-sectional view of the portal plugging device in a specific embodiment of the present invention;

[0027] Att Figure 2 is an axial cross-sectional view of the portal plugging device in a specific embodiment of the present invention.

[0028] In the figure: 1, inner lining wall; 2, portal steel ring; 3, grouting hole; 4, grouting channel; 5, rubber curtain cloth; 6, circular plate; 7, flap; 8, wire brush. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0029] The technical solutions of the present invention will be further described below with reference to the drawings.

[0030] The present invention relates to improvements to a plugging device and method for shield tunneling. The improved plugging device, by providing multiple grouting holes between two sets of sealing components, and the multiple grouting holes corresponding to the clock positions of the tunnel portal steel ring, allows slurry to be injected from the clock positions of the upper portion of the tunnel portal steel ring during plugging. This allows for more uniform slurry injection and a better plugging effect, and is simpler and more efficient than using membrane bags. The plugging method based on this plugging device has simple steps, is easy to operate, can quickly fill gaps, and has a good plugging effect.

[0031] See also Figure 1-2 As shown, a portal sealing device for the start of a shield tunnel is shown, which includes a portal steel ring 2 installed on the lining wall 1, at least two groups of sealing components arranged on the portal steel ring 2, and a plurality of grouting holes 3 pre-buried in the portal steel ring 2 and located between the at least two groups of sealing components. The sealing components are arranged around the circumference of the portal steel ring 2 and at least two groups of sealing components are arranged along the axial direction of the portal steel ring 2, and the plurality of grouting holes 3 are arranged at intervals along the circumference of the portal steel ring 2.

[0032] As a preferred solution, there are twelve grouting holes 3, located at twelve o'clock positions on the portal steel ring 2. This allows grouting to be simultaneously injected from the corresponding o'clock positions on both sides of the portal steel ring 2 to seal the hole. This allows the slurry to flow completely downward into the cavity of the portal steel ring 2, sealing the hole. Furthermore, multiple grouting channels 4 are formed on the inner lining wall 1. The multiple grouting holes 3 correspond to the multiple grouting channels 4 in a one-to-one manner and are interconnected. A grouting machine is connected to the outside of the grouting channels 4 to provide slurry.

[0033] The sealing assembly includes a rubber curtain 5, an annular plate 6, and a flap 7 located on either side of the rubber curtain 5. The rubber curtain 5, the annular plate 6, and the flap 7 are fixedly connected by bolts. The portal sealing device also includes at least one set of wire brushes 8 mounted on the portal steel ring 2 and located at the front of the sealing assembly.

[0034] As the shield machine advances, the rubber curtain 5 and flap 7 bend in the same direction as the shield's advance, opposing the flow of mud and water, providing a preliminary seal. Two sets of wire brushes 8 are provided, each with a grease injection hole. Grease is injected into the brushes to enhance the water blocking effect. Finally, slurry is injected into the two layers of rubber curtain 5. Once the slurry solidifies, the tunnel portal gap is completely sealed.

[0035] The blocking method based on the above-mentioned blocking device comprises the following steps:

[0036] (1) Preparation of slurry: Put clear water into a stirrer, start the stirrer, and then slowly and evenly add NSHS-1 slurry agent and NSHS-3 slurry agent into the clear water. After they are fully dissolved, slowly add NSHS-2 slurry agent and stir evenly to obtain the slurry.

[0037] Among them, the NSHS-1 type slurry agent has a viscosity increasing effect, which can simultaneously increase the mud funnel viscosity and plastic viscosity and reduce the water separation rate; the main use of the NSHS-2 type slurry agent is to block water at the portal ring, prevent slurry from gushing out in shallow overlying soil layers, block pores in sandy soil layers, gravel layers, weathered rock layers, etc., form a dense mud film in combination with other materials, prevent the excavation face from collapsing, and play a role in stabilizing the excavation face, also known as a plugging agent; the NSHS-3 type slurry agent has a viscosity increasing effect, which can simultaneously increase the mud funnel viscosity and plastic viscosity and reduce the water separation rate.

[0038] In this example, the mixing ratio of NSHS-1 slurry agent, NSHS-2 slurry agent, NSHS-3 slurry agent and clear water is 1:4:1:20. Further, slowly and evenly add 50 kg of NSHS-1 slurry agent and 50 kg of NSHS-3 slurry agent into 1 m³ of clear water. After they are fully dissolved, slowly add 200 kg of NSHS-2 slurry agent and stir evenly to obtain the slurry.

[0039] (2) Grouting before bin construction: After the cutting ring of the shield machine completely enters the wire brush 8, synchronously inject slurry into the 11 o'clock position and 1 o'clock position of the portal steel ring 2. Stop grouting when the grouting pressure reaches the first set value. Wait until the slurry completely flows into the cavity below the portal steel ring 2, and then synchronously inject slurry into the 9 o'clock position, 11 o'clock position, 1 o'clock position and 3 o'clock position of the portal steel ring 2. Stop grouting when the grouting pressure reaches the second set value. In this example, the first set value is 1 MPa, and the second set value is also 1 MPa,

[0040] Here, according to the length of the shield machine body, after the negative segments of the shield starting are assembled to a certain number of segments, observe the distance between the top of the cutter head and the face through the manhole. Adjust the propulsion stroke according to the actual distance. According to the designed axis slope, when the cutting ring of the shield completely enters the wire brush 8 and the minimum distance between the top of the cutter head and the face is about 50 mm, try to rotate the cutter head. This position is the grouting position before bin construction.

[0041] (3) Grouting during bin construction: When the liquid level of the face during shield starting slowly rises, inject slurry in sequence along the counterclockwise direction from the 11 o'clock position to the 8 o'clock position of the portal steel ring 2, then inject slurry in sequence along the clockwise direction from the 1 o'clock position to the 4 o'clock position of the portal steel ring 2, and finally inject slurry into the 12 o'clock position of the portal steel ring 2. During the grouting process at each position, stop grouting when the grouting pressure reaches the third set value. In this example, the third set value is 1 MPa.

[0042] During the initial lining construction, grouting is carried out simultaneously with the tunneling of the shield machine, which can prevent the slurry from sticking to the shield machine.

[0043] When the grouting pressure is greater than 1 MPa, the slurry cannot be injected anymore, indicating that the gap between the portal steel ring 2 and the shield machine has been sealed.

[0044] (4)Grouting during tunneling: During the tunneling of the shield machine, observe the muddy water leakage situation of the portal steel ring 2, and according to the principle of proximity, inject slurry through the grouting hole on the portal steel ring 2 that is closest to the muddy water leakage position to stop the leakage. Stop grouting when the muddy water leakage position no longer leaks.

[0045] During the tunneling of the shield machine, according to the actual tunneling situation of the tunnel, new gaps may appear between the shield machine and the portal steel ring 2. At this time, leakage stoppage can be carried out according to the principle of proximity.

[0046] Applying the sealing method of this embodiment can simply and efficiently seal the gap between the portal steel ring 2 and the shield machine, and solve the problem of muddy water leakage of the portal steel ring 2 during the initial stage of shield tunneling in the prior art.

[0047] The above embodiments are only for illustrating the technical concept and characteristics of the present invention, and their purpose is to enable those who are familiar with this technology to understand the content of the present invention and implement it. It cannot be used to limit the protection scope of the present invention. Any equivalent changes or modifications made according to the spirit of the present invention should be covered within the protection scope of the present invention.

Claims

1. A method for sealing a tunnel portal at the start of a shield tunnel, the method using a tunnel portal sealing device, characterized in that: The tunnel door sealing device includes a tunnel door steel ring installed on the inner lining wall and at least one set of steel brushes provided on the tunnel door steel ring. The tunnel door sealing device also includes a plurality of grouting holes pre-buried in the tunnel door steel ring. The plurality of grouting holes correspond to the clock positions of the tunnel door steel ring one by one. The tunnel door sealing method includes the following steps: (1) Preparation of slurry; (2) Grouting before building: After the cut ring of the shield machine completely enters the wire brush, slurry is injected into the 11 o'clock position and 1 o'clock position of the tunnel portal steel ring simultaneously. When the grouting pressure reaches the first set value, grouting is stopped. After the slurry completely flows into the cavity below the tunnel portal steel ring, slurry is injected into the 9 o'clock position, 11 o'clock position, 1 o'clock position and 3 o'clock position of the tunnel portal steel ring simultaneously. When the grouting pressure reaches the second set value, grouting is stopped; (3) Grouting during chamber construction: When the liquid level at the tunnel face where the shield machine starts slowly rises, slurry is injected into the positions of 11 o'clock to 8 o'clock of the tunnel portal steel ring in a counterclockwise direction, and then into the positions of 1 o'clock to 4 o'clock of the tunnel portal steel ring in a clockwise direction, and finally into the position of 12 o'clock of the tunnel portal steel ring. During the grouting process at each position, grouting is stopped when the grouting pressure reaches the third set value; (4) Grouting during excavation: During the excavation of the shield machine, the mud and water leakage of the tunnel portal steel ring is observed, and based on the principle of proximity, slurry is injected through the grouting hole on the tunnel portal steel ring closest to the mud and water leakage location to plug the leakage. Grouting is stopped when the mud and water leakage location no longer leaks.

2. The method for blocking a tunnel portal at the start of a shield tunnel according to claim 1, characterized in that: A plurality of grouting channels are provided on the inner lining wall, and the plurality of grouting holes correspond to the plurality of grouting channels one by one and are interconnected.

3. The method for sealing a tunnel portal at the start of a shield tunnel according to claim 1, characterized in that: The tunnel door sealing device also includes at least two sets of sealing components arranged on the tunnel door steel ring, and the wire brush is located in the front part of the sealing component.

4. The method for sealing a tunnel portal at the start of a shield tunnel according to claim 3, characterized in that: The sealing assembly includes a rubber curtain, an annular plate and a flap located on both sides of the rubber curtain, and the rubber curtain, the annular plate and the flap are fixedly connected.

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