Tunnel portal chiseling method for shield diaphragm wall

Abstract

The invention discloses a tunnel portal chiseling method for a shield diaphragm wall, which is used for enabling a shield tunneling machine to conveniently penetrate through a tunnel portal when a cutter head of the shield tunneling machine reaches a soil facing surface of the diaphragm wall, and comprises the following steps: after grouting reinforcement is completed, carrying out horizontal hole exploration, and chiseling H-shaped steel of the tunnel portal of the diaphragm wall in sections when no water flows and sand flows in the horizontal hole exploration process; after the H-shaped steel is chiseled away, steel bars on the soil facing face of the underground diaphragm wall tunnel portal are cut off in a segmented mode, and the segmented chiseling-away process of the H-shaped steel comprises the steps that joints, on the two sides of the tunnel portal, of the H-shaped steel are divided into three segments from top to bottom, the first segment of the H-shaped steel at the bottom is chiseled away, then the second segment of the H-shaped steel at the top is chiseled away, and after the second segment is chiseled away, the third segment of the middle is chiseled away. According to the method, the H-shaped steel of the underground diaphragm wall tunnel portal is chiseled away in a segmented mode, then the water drill is adopted for drilling to cut off the soil facing face steel bars, water-rich sand layer tunnel portal chiseling can be facilitated, the construction risk is reduced, and a shield can receive and use the tunnel portal conveniently.

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, the ground-connected wall (underground continuous wall) is a common retaining structure used to prevent groundwater infiltration and soil sliding. The shield machine needs to pass through the portal on the ground-connected wall for starting and receiving. 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] The process of chiseling out the shield tunnel portal often involves the processing of the steel sections and steel bars in the ground-anchored wall to ensure the smooth opening and closing of the tunnel portal. In the prior art, the structure of the ground-anchored 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 prior art, the general operating steps are as follows: first, the steel bars on the soil surface and the steel bar protective layer concrete are manually chiseled off, and then the concrete between the steel bars on the soil surface and the back soil surface of the ground-connected wall is chiseled off from top to bottom by a pneumatic pick, and then the steel bars on the soil surface are manually cut off. At this time, only 7 cm of the ground-connected wall concrete remains. There are great safety hazards in manual operations. 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 reason, 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 tunnel door of a shield ground-connected wall. The H-shaped steel of the tunnel door of the ground-connected wall is chiseled out in sections, and then a water drill is used to drill holes and cut off the steel bars facing the soil surface. This can facilitate the chiseling of the tunnel door 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 door of a shield ground-connected wall, which is used to facilitate the shield machine to pass through the tunnel door when the shield machine cutter head reaches the soil surface of the ground-connected wall, comprising:

[0009] After the shield 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;

[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 H-beam at the bottom, then chiseling the second section of the H-beam at the top, and after the chiseling of the second section is completed, chiseling the third section in the middle;

[0012] Each section in the segmented chiseling process does not exceed a specified length, and after completing a section of chiseling, mortar is used to fill the chiseling 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 position of 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 wing is cut off in blocks, and the steel bar protective layer facing the soil surface of the ground-connected 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 waterproofing 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 performed when there is no water leakage or sand leakage.

[0020] The present invention provides a method for chiseling out a tunnel of a shield ground-connected wall. Compared with the prior art, the present invention has the following beneficial effects:

[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 need to chisel 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 receive and use, and saves construction time, which is convenient for 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 tunnel portal structure is not reduced, the risk of construction site is effectively controlled, the risk of exposure and leakage and the collapse of the tunnel portal in the water-rich sand layer are reduced, and the problem of soil instability or groundwater leakage caused by one-time large-scale excavation is avoided. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The drawings constituting a part of the present application are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

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

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

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

[0027] Figure 4 A schematic diagram of the steel bar cut-off holes facing 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 of the present invention. DETAILED DESCRIPTION

[0029] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than 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 in 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 a tunnel portal of a shield ground-connected 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 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 tunnel, 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, horizontal drilling is carried out. When there is no water or sand flow during the horizontal drilling, the H-shaped steel of the ground-connected wall door is removed 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 reinforcement quality at the end.

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

[0036] Specifically, the H-shaped steel joints are processed in sections from bottom to top. According to the site conditions, the processing is divided into 3 sections, each section is no longer than 1.2m, and after one section is processed, mortar is used to fill it 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, and mortar is used to fill each section 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 process of segmented removal of H-beam specifically includes: dividing the joints of H-beam on both sides of the portal into three sections, firstly removing the first section of H-beam at the bottom, then removing the second section at the top, and then removing the third section in the middle after the second section is removed;

[0039] At this time, the H-steel can be processed without reducing the strength of the portal structure, effectively controlling the risks at 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 chiseling position is set at the bottom of the portal, and the chiseling width is 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 inner steel wing plate 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;

[0041] After a piece of the H-shaped inner steel wing is cut off, double-fast cement is used to seal the ground-connected 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 water-stopping agent can be injected through horizontal exploration holes with a depth of 1m behind the ground-connected wall, which can play a role in rapid water stopping, thereby preventing soil loss and ensuring the safety and stability of the construction site.

[0044] (2) After the H-beam is chiseled off, 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 concrete structure of the portal 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 use a water drill to drill holes and cut off the steel bars facing the soil surface. It does not need to chisel out concrete, and the construction risk is low. It is conducive to the chiseling of the portal in the water-rich sand layer, reduces construction risks, is convenient for the shield to accept and use, and saves construction time. It has high economic benefits and is easy to use efficiently.

[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 chiseling method is prone to cause soil instability, groundwater leakage and other problems. Therefore, this application uses the method of chiseling out the H-shaped steel in sections and backfilling the 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 principle of the present invention should be included in the protection scope 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 in a certain specific posture. If the specific posture changes, the directional indication 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 used for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In addition, the meaning of "and / or" appearing in the full text includes three parallel schemes. Taking "A and / or B" as an example, it includes scheme A, or scheme B, or schemes that A and B meet 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 the field to implement. When the combination of technical solutions is contradictory or cannot be implemented, it should be considered 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 door of a shield ground-connected wall, which is used to facilitate the shield machine to pass through the tunnel door when the shield machine cutter head reaches the soil surface of the ground-connected 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-connected wall opening are cut off in sections.

2. The method for removing the tunnel door of the shield ground-connected wall according to claim 1, characterized in that: 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 H-beam at the bottom, then chiseling the second section of the H-beam at the top, and after the chiseling of the second section is completed, chiseling the third section in the middle is performed; Each section in the segmented chiseling process does not exceed a specified length, and after completing a section of chiseling, mortar is used to fill the chiseling before proceeding to the next section of chiseling.

3. The method for removing the tunnel door of the shield ground-connected wall according to claim 2, characterized in that: The specific chiseling steps in each chiseling process in the segmented chiseling process include: Select the designated chiseling position, 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 wing is cut off in blocks, and the steel bar protective layer on the soil surface of the ground-connected wall is not damaged during the removal process; 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 is set on the outer layer to reinforce the backfill mortar.

4. The method for removing the tunnel door of the shield ground-connected wall according to claim 1, characterized in that: If there is water and sand flow during the horizontal drilling process, water-soluble polyurethane waterproofing is injected through the horizontal drilling, and the depth of the horizontal drilling is to a specified distance behind the ground-connected wall.

5. The method for removing the tunnel door of the shield ground-connected wall according to claim 1, characterized in that: 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.

6. The method for removing the tunnel door of the shield ground-connected wall according to claim 1, characterized in that: During the process of segmentally cutting off the steel bars facing the soil surface of the ground-connected wall opening, if water leakage or sand leakage occurs, double-liquid grouting is used for sealing, and drilling construction is performed when there is no water leakage or sand leakage.

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