A method for removing the portal of a shield ground-connected wall

Abstract

The present invention discloses a method for chiseling a portal of a shield tunneling diaphragm wall, which is used to facilitate the shield machine to pass through the portal when the shield machine cutterhead reaches the soil surface of the diaphragm wall. The method comprises: performing a horizontal exploration after grouting reinforcement is completed. When there is no water or sand flowing during the horizontal exploration, the H-shaped steel of the diaphragm wall portal is chiseled out in sections; after the H-shaped steel is chiseled out, the steel bars of the diaphragm wall portal are cut off in sections. The process of chiseling out the H-shaped steel in sections includes: dividing the joints of the H-shaped steel on both sides of the portal into three sections, first chiseling out the first section of the H-shaped steel at the bottom, then chiseling out the second section of the H-shaped steel at the top, and after the second section is chiseled out, chiseling out the third section in the middle. By chiseling out the H-shaped steel of the diaphragm wall portal in sections and then using a water drill to drill and cut off the steel bars of the soil surface, the present invention can facilitate the chiseling of the portal in a water-rich sand layer, reduce construction risks, and facilitate the acceptance and use of the shield machine.

Description

Technical Field

[0001] The invention relates to the technical field of shield construction, and in particular to a method for chiseling out a tunnel door of a shield ground-connected wall. Background Art

[0002] When carrying out shield construction in water-rich sand layers, ground-connected walls (underground continuous walls) are common retaining structures used to prevent groundwater infiltration and soil sliding. The shield machine needs to pass through the portal on the ground-connected wall for departure and reception. At this time, in order to ensure that the shield machine can enter and exit smoothly, the portal usually needs to be chiseled out.

[0003] During the shield tunneling process, the steel sections and steel bars in the ground-connected wall are often processed to ensure the smooth opening and closing of the tunnel. In the existing technology, the structure of the ground-connected wall usually includes materials such as concrete, steel sections and steel mesh, which together constitute a solid enclosure structure.

[0004] In the conventional chiseling operation of the shield tunnel portal in the existing technology, the general operating steps are as follows: first, the steel bars on the facing soil surface and the steel bar protective layer concrete are manually chiseled off, and then the concrete between the steel bars on the facing soil surface and the back soil surface of the ground-connected wall is chiseled off from top to bottom with a jackhammer, and then the steel bars on the facing soil surface are manually cut off. At this time, only 7 cm of concrete remains in the ground-connected wall. There are great safety hazards in manual operation. If the quality of the end reinforcement is not in place, there is a risk of water and sand gushing out, causing ground collapse.

[0005] For this purpose, the present application proposes a method for chiseling out a tunnel door of a shield ground-connected wall to solve the above-mentioned technical problems. Summary of the Invention

[0006] The main purpose of the present invention is to provide a method for chiseling out the portal of a shield ground-connected wall. By chiseling out the H-shaped steel of the portal of the ground-connected wall in sections, and then using a water drill to drill holes and cut off the steel bars facing the soil surface, it is possible to facilitate the chiseling of the portal in the water-rich sand layer, reduce construction risks, and facilitate the acceptance and use of the shield.

[0007] The present invention adopts the following technical solutions to solve the above technical problems:

[0008] A method for chiseling out a tunnel portal of a shield ground-connected wall, used to facilitate the shield machine to pass through the tunnel portal when the shield machine cutter head reaches the soil surface of the ground-connected wall, comprising:

[0009] After the shield grouting reinforcement is completed, horizontal drilling is carried out. When there is no water or sand flow during the horizontal drilling process, the H-shaped steel of the ground-connected wall door is removed in sections;

[0010] After the H-shaped steel is removed, the steel bars facing the soil surface of the ground-connected wall opening are cut off in sections.

[0011] Preferably, the segmented chiseling process of the H-beam includes: dividing the joints of the H-beam on both sides of the portal into three sections, first chiseling the first section of the bottom H-beam, then chiseling the second section of the top H-beam, and after the second section is chiseled out, chiseling the third section in the middle is carried out;

[0012] Each section in the segmented chiseling process does not exceed a specified length, and after completing one section of chiseling, mortar is used to fill the gap before proceeding to the next section of chiseling.

[0013] Preferably, the specific chiseling steps in each chiseling process in the segmented chiseling process include:

[0014] Select the designated chiseling position and set the chiseling width to 0.5m outside the H-beam web to the portal steel ring inside the web. After chiseling the designated width, cut off the H-beam web.

[0015] After the H-shaped steel web is cut off, the inner H-shaped steel flange is cut off in blocks, and the steel bar protective layer on the soil surface of the ground diaphragm wall is not damaged during the removal process;

[0016] After a piece of the H-shaped inner steel wing plate is cut off, double-fast cement is used to seal the ground-connected wall at the processed position, and a round steel mesh with a diameter of 10 is set on the outer layer to reinforce the backfill mortar.

[0017] Preferably, if there is water and sand flow during the horizontal drilling process, water-soluble polyurethane waterstop is injected through the horizontal drilling, and the depth of the horizontal drilling is to a specified distance of 1m behind the ground-connected wall.

[0018] Preferably, a water drill is used to cut the steel bars facing the soil surface of the ground-connected wall opening in sections, and the length of each section is set within a specified range, generally not more than 30 cm.

[0019] Preferably, if water leakage or sand leakage occurs during the process of segmented cutting of the steel bars facing the soil surface of the ground-connected wall opening, double-liquid grouting is used for sealing, and drilling construction is carried out when there is no water leakage or sand leakage.

[0020] The present invention provides a method for removing a portal in a shield tunneling ground-connected wall. Compared with the prior art, the present invention has the following advantages:

[0021] 1. The present invention can maintain the stability of the portal structure while gradually weakening the strength of the portal concrete structure. It does not require the removal of concrete, and the construction risk is low. It is conducive to the removal of the portal in the water-rich sand layer, reducing the construction risk, facilitating the shield machine to accept and use it, and at the same time saving the construction period and facilitating efficient use.

[0022] 2. The present invention removes the first section of H-shaped steel in sections and then backfills the hole. While processing the H-shaped steel, the strength of the portal structure is not reduced, the risks at the construction site are effectively controlled, the risks of exposure and leakage and the collapse of the portal in the water-rich sand layer are reduced, and the problems of soil instability or groundwater leakage caused by one-time large-scale excavation are avoided. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The accompanying drawings, which constitute part of this application, are intended to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are intended to explain the present invention and do not constitute an undue limitation of the present invention. In the accompanying drawings:

[0024] Figure 1 It is a schematic diagram of the overall process of the present invention;

[0025] Figure 2 This is a schematic diagram of the H-beam joint processing process of the present invention;

[0026] Figure 3 This is a schematic plan view of the H-shaped steel joint structure of the present invention;

[0027] Figure 4 Schematic diagram of the cut-off holes for the steel bars on the soil surface of the ground-connected wall of the present invention;

[0028] Figure 5 This is a construction site diagram of the soil surface steel bar water drill cutting method of the present invention. DETAILED DESCRIPTION

[0029] 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 embodiments described are only part of the embodiments of the present invention, not all of the embodiments. In the absence of conflict, the embodiments in this application and the features in the embodiments can be combined with each other. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0030] In the embodiment, see Figures 1 to 5 .

[0031] The present invention provides a method for chiseling out the portal of a shield ground-connected wall, which is used to facilitate the shield machine to pass through the portal when the shield machine cutter head reaches the soil surface of the ground-connected wall. At this time, the soil surface of the ground-connected wall is glass fiber reinforcement, and the back-soil surface is steel bar. When the shield machine receives the wall, the back-soil surface steel bar is stripped off, and the shield machine cuts and grinds through. Under normal circumstances, when the shield machine excavates to about 150 rings remaining, the back-soil surface steel bar can be stripped off to prepare for receiving.

[0032] like Figure 1 As shown, the method for removing the tunnel door includes:

[0033] (1) After the shield grouting reinforcement is completed, conduct horizontal drilling. When there is no water or sand flow during the horizontal drilling process, remove the H-shaped steel of the ground-connected wall door in sections;

[0034] At this time, by conducting horizontal exploration holes after the grouting reinforcement is completed, the stability of the ground-connected wall can be tested, thereby ensuring the safety of the construction and avoiding the risk of water and sand gushing caused by inadequate end reinforcement quality.

[0035] Grouting reinforcement and horizontal drilling are both routine technical operations in shield construction, and their specific operating steps and principles will not be described here.

[0036] Specifically, the H-shaped steel joints are processed in sections from bottom to top. According to the site conditions, the treatment is divided into 3 sections, each section is no longer than 1.2m, and after one section is processed, it is filled with mortar before the next section is processed.

[0037] At this time, the H-shaped steel on the windward side of the ground-connected wall opening is removed in sections. After each section is removed, mortar is filled in before the next section is removed. This can gradually weaken the structural strength while maintaining local stability, thereby reducing the overall construction risk.

[0038] The specific process of segmented removal of H-beams includes: dividing the joints of H-beams on both sides of the portal into three sections, first removing the first section of H-beams at the bottom, then the second section at the top, and after the second section is removed, the third section in the middle is removed;

[0039] At this time, the H-shaped steel can be processed without reducing the strength of the portal structure, effectively controlling the risks on the construction site, reducing the risk of exposure and leakage and the collapse of the portal in the water-rich sand layer, and avoiding soil instability or groundwater leakage caused by one-time large-scale excavation.

[0040] For further reference, Figure 3 The first section of steel plate is chiseled out at the bottom of the portal, with a chiseling width from 0.5m outside the H-shaped steel web to the portal steel ring inside the web. After the chiseling is completed, the H-shaped steel web is cut off. After the web is cut off, the inner H-shaped steel wing is cut off in blocks. The steel bar protective layer facing the soil surface of the ground-connected wall must not be damaged during the chiseling process.

[0041] After a piece of H-shaped inner steel wing is cut off, double-fast cement is used to seal the ground wall at the processed position, and a 10-diameter round steel mesh is set on the outer layer to reinforce the backfill mortar. After the first section is processed, the next section is processed, and so on. Figure 2 As shown, it can enhance the strength of temporary support and ensure the stability of the working environment;

[0042] It can be explained that during the chiseling process, the deformation of the ground-connected wall needs to be continuously monitored;

[0043] In addition, it is necessary to further add that if there is a phenomenon of flowing water and sand, water-soluble polyurethane waterstop should be injected through a horizontal exploration hole. The depth of the horizontal exploration hole should be 1m behind the ground-connected wall, which can quickly stop the water, thereby preventing soil loss and ensuring the safety and stability of the construction site.

[0044] (2) After the H-beam is chiseled out, refer to Figure 4 and Figure 5 The vertical main reinforcement of the ground-connected wall is cut into sections with a water drill, and the length of each section is no more than 30 cm. During the cutting process, if water leakage or sand leakage occurs, double-liquid grouting is used to seal it. Drilling construction is carried out when there is no water leakage or sand leakage. The cutting depth and range can be accurately controlled to improve construction efficiency and safety.

[0045] In summary, this method can gradually weaken the strength of the portal concrete structure while maintaining the stability of the portal structure by chiseling out the H-shaped steel of the ground-connected wall portal in sections, and then using a water drill to drill holes and cut off the steel bars facing the soil. It does not require chiseling out concrete, has a low construction risk, is conducive to chiseling out the portal in the water-rich sand layer, reduces construction risks, is convenient for the shield to accept and use, and at the same time saves construction time, has high economic benefits, and is convenient for efficient use.

[0046] It should also be noted that the geological structures in different regions vary greatly. The method of this application is designed based on specific geological conditions and is suitable for sand layer areas rich in groundwater. In this environment, the traditional overall removal method is prone to cause soil instability, groundwater leakage and other problems. Therefore, this application uses the method of removing H-shaped steel in sections and backfilling mortar in time to effectively control such risks.

[0047] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

[0048] In addition, it should be noted that if the embodiments of the present invention involve directional indications (such as up, down, left, right, front, back, etc.), the directional indications are only used to explain the relative position relationship, movement status, etc. between the components under a certain specific posture. If the specific posture changes, the directional indications will also change accordingly.

[0049] In addition, if there are descriptions involving "first", "second", etc. in the embodiments of the present invention, the descriptions of "first", "second", etc. are only for descriptive purposes and cannot be understood as indicating or suggesting their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of such features. In addition, the meaning of "and / or" appearing throughout the text includes three parallel schemes. Taking "A and / or B" as an example, it includes scheme A, or scheme B, or schemes in which A and B are satisfied at the same time. In addition, in the embodiments of the present invention, "multiple" refers to more than two. In addition, the technical solutions between the various embodiments can be combined with each other, but it must be based on the ability of ordinary technicians in this field to implement. When the combination of technical solutions is mutually contradictory or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

Claims

1. A method for chiseling out a tunnel portal of a shield tunneling diaphragm wall, which is used to facilitate the shield machine to pass through the tunnel portal when the shield machine cutter head reaches the soil surface of the diaphragm wall, and is characterized in that: include: After the grouting reinforcement is completed, a horizontal exploration hole is carried out. When there is no water or sand flow during the horizontal exploration hole, the H-shaped steel of the ground-connected wall door is removed in sections; After the H-shaped steel is removed, the steel bars facing the soil surface of the ground diaphragm wall opening are cut off in sections; The H-beam segmented chiseling process includes: dividing the joints of the H-beam on both sides of the portal into three sections, first chiseling the first section of the bottom H-beam, then chiseling the second section of the top H-beam, and after the second section is chiseled out, chiseling the third section in the middle is carried out; Each section in the segmented chiseling process does not exceed a specified length, and after completing one section of chiseling, mortar is used to fill the gap before proceeding to the next section of chiseling; The specific chiseling steps in each chiseling process in the segmented chiseling process include: Select the designated chiseling location and cut off the H-beam web after chiseling to the designated width; After the H-shaped steel web is cut off, the inner H-shaped steel flange is cut off in blocks, and the steel bar protective layer on the soil surface of the ground diaphragm wall is not damaged during the removal process; After a piece of the H-shaped inner steel wing is cut off, double-fast cement is used to seal the treated location of the ground wall, and round steel mesh is installed on the outer layer to reinforce the backfill mortar; If there is water and sand flow during the horizontal drilling process, water-soluble polyurethane waterstop is injected through the horizontal drilling, and the depth of the horizontal drilling is to the specified distance behind the ground-connected wall.

2. The method for removing the tunnel door of a shield ground-connected wall according to claim 1, wherein: In the process of segmented cutting of the steel bars facing the soil surface of the ground-connected wall opening, a water drill is used for cutting, and the length of each segment is set within a specified range.

3. The method for removing the tunnel door of a shield ground-connected wall according to claim 1, wherein: During the process of segmented cutting of the steel bars facing the soil surface of the ground-connected wall opening, if water and sand leakage occurs, double-liquid grouting is used to seal it, and drilling construction is carried out when there is no water and sand leakage.

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