A method for breaking up steel joints in diaphragm walls

Abstract

This invention belongs to the field of diaphragm wall construction technology and relates to a method for removing steel joints in diaphragm walls. The method includes the following steps: reinforcing the soil outside the location of the steel joint to form a complete reinforced body; mechanically drilling a hole close to the diaphragm wall at the steel joint location and lowering a steel casing; grouting and sealing the bottom of the steel casing; removing the mud from inside the steel casing; erecting a construction platform inside the steel casing and grouting to reinforce the soil behind the diaphragm wall; cutting the steel casing in sections from bottom to top within the area where the steel joint needs to be removed; removing the steel joint; backfilling the removed area with plain concrete; welding the gap in the steel casing to seal it; after completing one section, raising the operating platform to proceed with the next section until the removal is complete; hoisting out the operating platform and equipment inside the steel casing and removing the steel casing; and then using a tunnel boring machine (TBM) to pass through the diaphragm wall. This invention solves many problems associated with traditional techniques for removing steel joints in diaphragm walls, such as high risk, large investment, and long construction period.

Description

Technical Field

[0001] This invention belongs to the field of diaphragm wall construction technology, and relates to a method for breaking diaphragm wall steel joints, and more particularly to a construction method for breaking diaphragm wall steel joints before a shield tunnel passes through a diaphragm wall without pre-reserved conditions. Background Technology

[0002] When constructing underground structures using the cut-and-cover method, diaphragm walls are often used as retaining structures. If the planning stage considers the long-term tunnel boring machine (TBM) passage conditions, the diaphragm walls will adopt forms such as milling joints or interlocking pipe joints to facilitate direct cutting and passage by the TBM.

[0003] Due to planning adjustments and other reasons, shield tunnels often need to pass through structures without pre-reserved diaphragm walls. Directly cutting through retaining piles and diaphragm walls with shields is already quite common, but there is no precedent for directly cutting through steel joints, making the construction extremely difficult and risky.

[0004] Currently, the commonly used methods involve excavating tunnels or creating vertical shafts adjacent to existing diaphragm walls to manually remove the steel structures within the shield tunnel's crossing area. Traditional demolition techniques involve high construction risks, long construction periods, and high project costs. They also easily impact existing structures and have significant environmental impacts, especially in saturated soft soil strata, where traditional methods are particularly unsuitable.

[0005] In view of the above situation, proposing a new method for breaking up steel joints in diaphragm walls has significant practical implications. Summary of the Invention

[0006] In view of the many shortcomings of traditional tunnel or shaft demolition methods, this invention proposes a method for demolishing diaphragm wall steel joints that has low construction risk, short cycle and low cost.

[0007] The technical solution of this invention is: a method for breaking up a steel joint in a diaphragm wall, comprising the following steps:

[0008] S1: Reinforce the soil outside the location of the diaphragm wall steel joint to form a complete reinforced body;

[0009] S2: At the location of the steel joint, a hole is mechanically drilled close to the ground diaphragm wall and a steel casing is installed. The bottom of the steel casing is grouted and sealed, and the mud inside the steel casing is removed.

[0010] S3: Erect an operating platform inside the steel casing and grout to reinforce the soil behind the diaphragm wall;

[0011] S4: Cut the steel casing in sections from bottom to top within the range of the steel joint to be removed, remove the steel joint, backfill the area with plain concrete, and weld the gap in the steel casing after backfilling. After completing one section, raise the operating platform to carry out the next section of construction until the steel joint in the shield tunneling area is removed.

[0012] S5: Lift out the operating platform and equipment inside the steel sleeve and remove the steel casing;

[0013] S6: Construction of shield tunneling through diaphragm wall.

[0014] Preferably, the method of soil reinforcement outside the steel joint structure in step S1 is selected according to the stratum conditions, and can be high-pressure jet grouting, mixing piles, sleeve valve pipe grouting, drilling and injection machine grouting reinforcement, etc.

[0015] More preferably, the range of the solidified body in step S1, the thickness of the bottom sealing in S2, and the range of the grouting reinforcement behind the wall in S3 are determined according to the stratum and water pressure.

[0016] More preferably, the diameter of the steel casing in step S2 is about 2m, but it can also be adjusted according to construction needs.

[0017] In a further preferred embodiment, the grouting reinforcement of the soil behind the diaphragm wall in step S3 can be carried out by grouting pipe or drilling and grouting machine, depending on the construction conditions. The grouting holes are arranged along both sides of the steel joint. When grouting pipe is used, the grouting pipe should be removed after grouting is completed.

[0018] In a further preferred embodiment, when the bottom of the diaphragm wall steel joint is located within the shield tunneling range in step S3, grouting reinforcement is also required for the bottom area of ​​the diaphragm wall.

[0019] In a further preferred embodiment, before cutting the steel casing in step S4, it should be calculated and determined whether to install temporary internal supports inside the steel casing based on the geological conditions and water pressure.

[0020] In a further preferred embodiment, the segment lengths of the steel sleeve cutting, diaphragm wall steel removal, plain concrete backfilling, and steel casing welding and sealing operations in step S4 generally do not exceed 1m.

[0021] More preferably, in step S5, the steel sleeve should be removed while backfilling is being done to prevent the hole from collapsing.

[0022] The present invention has the following significant advantages:

[0023] 1. This invention solves many problems of traditional technology, such as high risk, large investment, and long construction period, by adopting a steel casing support system through a simple construction procedure and segmented chiseling of the steel joints in the shield tunneling area.

[0024] 2. This invention uses steel casing support, which is simpler to construct, has a shorter construction period, and has less impact on the surrounding environment compared to traditional open-cut shafts.

[0025] 3. This invention has low requirements for construction sites, and the difficulty and cost of pipeline relocation and traffic diversion are relatively low.

[0026] 4. The invention has low engineering cost, the steel casing can be recycled and reused, and generates little waste.

[0027] In addition, the inventive step evidence for this invention is also reflected in the following important aspects:

[0028] 1. The technical solution of this invention fills a technical gap in the industry at home and abroad: traditional methods all adopt open-cut vertical shaft construction, while this invention creatively applies steel-cased concrete support and removes the I-beam joints in sections.

[0029] 2. Does the technical solution of this invention solve the technical problems that people have long wanted to solve but have never been able to solve successfully? This invention solves the problems of large land occupation, high difficulty in pipeline relocation and traffic diversion, and high cost of traditional methods. Attached Figure Description

[0030] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. However, it should be understood that these drawings are designed for illustrative purposes only and are not intended to limit the scope of the present invention. Furthermore, unless specifically indicated, these drawings are intended only to conceptually illustrate the structural construction described herein and are not necessarily drawn to scale.

[0031] Figure 1 This is a planar schematic diagram of step S1 of the present invention;

[0032] Figure 2 This is a planar schematic diagram of step S2 of the present invention;

[0033] Figure 3 This is a planar schematic diagram of step S3 of the present invention;

[0034] Figure 4 This is a schematic diagram of the steel sleeve cutting and diaphragm wall steel removal in step S4 of the present invention.

[0035] Figure 5 This is a schematic diagram of the plan view of step S4 of the present invention: grouting backfilling and steel casing welding closure.

[0036] Figure 6 This is a cross-sectional schematic diagram of Embodiment 1 of the present invention;

[0037] Figure 7 This is a cross-sectional schematic diagram of Embodiment 2 of the present invention;

[0038] Figure 8 This is a cross-sectional view of step S1 in Embodiment 1 of the present invention;

[0039] Figure 9 This is a cross-sectional view of step S2 in Embodiment 1 of the present invention;

[0040] Figure 10 This is a cross-sectional view of step S3 in Embodiment 1 of the present invention;

[0041] Figure 11 This is a cross-sectional view of the construction of the first section of the steel sleeve being cut off and the steel section of the diaphragm wall being demolished in step S4 of embodiment one of the present invention.

[0042] Figure 12 This is a cross-sectional view of the first section of plain concrete backfilling and steel casing welding and sealing construction in step S4 of embodiment one of the present invention;

[0043] Figure 13 This is a cross-sectional view of the second section of construction in step S4 of embodiment one of the present invention;

[0044] Figure 14 This is a cross-sectional view after step S4 of embodiment one of the present invention has been completed;

[0045] Figure 15 This is a schematic diagram of the shield tunneling machine passing through after the steel sleeve is removed in step S5 of an embodiment of the present invention. Detailed Implementation

[0046] First, it should be noted that the specific structure, features, and advantages of the present invention will be described in detail below by way of examples. However, all descriptions are for illustrative purposes only and should not be construed as limiting the present invention in any way. Furthermore, any single technical feature described or implied in the embodiments mentioned herein, or any single technical feature shown or implied in the accompanying drawings, can still be arbitrarily combined or deleted among these technical features (or their equivalents) to obtain more other embodiments of the present invention that may not be directly mentioned herein. Additionally, for the sake of simplifying the drawings, the same or similar technical features may be indicated only in one place in the same drawing.

[0047] In the description of this invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0048] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances. The invention will now be described in detail with reference to the accompanying drawings. Example 1

[0049] like Figures 1-6 , Figures 8-15 A method for removing a steel joint in a diaphragm wall includes the following steps:

[0050] S1: Jet grouting piles are used to reinforce the soil outside the steel joint of the diaphragm wall to form a complete reinforced body. The range of the reinforced body is determined according to the stratum and water pressure.

[0051] S2: At the location of the steel joint, a hole is mechanically drilled close to the diaphragm wall and a steel casing is installed. The diameter of the steel casing is 2m. The bottom of the steel casing is sealed by grouting, and then the mud inside the steel casing is removed.

[0052] S3: An operating platform is erected inside the steel casing to reinforce the soil behind the diaphragm wall through grouting. Grouting reinforcement of the soil behind the diaphragm wall is performed using either grouting pipes or a drilling and grouting machine, depending on the construction conditions. Grouting holes are arranged along both sides of the steel joint. When using grouting pipes, the pipes should be removed after grouting is completed. If the bottom of the diaphragm wall steel joint is located within the shield tunneling area, grouting reinforcement is required for the bottom area of ​​the diaphragm wall. Taking this embodiment as an example, grouting pipes are used to reinforce the soil behind the diaphragm wall, with grouting holes arranged along both sides of the steel joint. The grouting pipes should be removed after grouting is completed.

[0053] S4: Grouting is carried out on the soil between the steel casing and the diaphragm wall. The I-beam joint is removed in 1m sections from bottom to top. The construction procedure is as follows: Temporary internal support is set up inside the steel casing, the steel casing within the range of the steel joint to be removed is cut off, the steel joint is removed, plain concrete is used to backfill the removed area, and the gap in the steel casing is welded and sealed after backfilling. After one section is completed, the operating platform is raised to carry out the next section until the removal is completed.

[0054] S5: Lift out the operating platform and equipment inside the steel sleeve, and remove the steel sleeve by grouting and removing it simultaneously;

[0055] S6: Construction of shield tunneling through diaphragm wall.

[0056] The method for removing the diaphragm wall steel joint in this embodiment adopts a steel casing support system and removes the steel joint in sections within the shield tunneling area. Compared with the traditional open-cut shaft, the construction method is simple, the construction period is short, the project cost is low, the construction risk is small, and the impact on the surrounding environment is small. Example 2

[0057] like Figures 1-7 A method for removing a steel joint in a diaphragm wall includes the following steps:

[0058] S1: Use sleeve valve pipe grouting to reinforce the soil outside the steel joint of the diaphragm wall to form a complete reinforced body. The range of the reinforced body is determined according to the stratum and water pressure.

[0059] S2: At the location of the steel joint, a hole is mechanically drilled close to the diaphragm wall and a steel casing is installed. The diameter of the steel casing is 2m. The bottom of the steel casing is sealed by grouting, and then the mud inside the steel casing is removed.

[0060] S3: An operating platform is erected inside the steel casing to reinforce the soil behind the diaphragm wall through grouting. Grouting reinforcement of the soil behind the diaphragm wall is performed using either grouting pipes or a drilling and grouting machine, depending on the construction conditions. Grouting holes are arranged along both sides of the steel joint. When using grouting pipes, the pipes should be removed after grouting is completed. If the bottom of the diaphragm wall steel joint is located within the shield tunneling area, grouting reinforcement is required for the bottom area of ​​the diaphragm wall. Taking this embodiment as an example, grouting pipes are used to reinforce the soil behind the diaphragm wall, with grouting holes arranged along both sides of the steel joint. The grouting pipes should be removed after grouting is completed.

[0061] S4: Grouting is carried out on the soil between the steel casing and the diaphragm wall. The steel joint is removed in 1m sections from bottom to top. The construction procedure is as follows: cut off the steel casing in the area where the steel joint needs to be removed, remove the steel joint, backfill the area with plain concrete, and weld the gap in the steel casing after backfilling. After completing one section, raise the operating platform to carry out the next section of construction until the removal is completed.

[0062] S5: Lift out the operating platform and equipment inside the steel sleeve, and remove the steel sleeve by grouting and removing it simultaneously;

[0063] S6: Construction of shield tunneling through diaphragm wall.

[0064] The method for removing the diaphragm wall steel joint in this embodiment adopts a steel casing support system and removes the steel joint in sections within the shield tunneling area. Compared with the traditional open-cut shaft, the construction method is simple, the construction period is short, the project cost is low, the construction risk is small, and the impact on the surrounding environment is small.

[0065] The above embodiments have provided a detailed description of the present invention, but the content described is only a preferred embodiment of the present invention and should not be considered as limiting the scope of the present invention. All equivalent variations and improvements made within the scope of the present invention should still fall within the patent coverage of the present invention.

Claims

1. A method for breaking up a steel joint in a diaphragm wall, characterized in that, The method for breaking steel joints when a tunnel boring machine (TBM) passes through a diaphragm wall without pre-reserved conditions includes the following steps: S1: Reinforce the soil outside the location of the diaphragm wall steel joint to form a complete reinforced body; S2: At the location of the steel joint, a hole is mechanically drilled close to the ground diaphragm wall and a steel casing is installed. The bottom of the steel casing is grouted and sealed, and the mud inside the steel casing is removed. S3: Erect an operating platform inside the steel casing and grout to reinforce the soil behind the diaphragm wall; S4: Cut the steel casing in sections from bottom to top, removing the steel joints. After removing the steel joints, backfill the area with plain concrete. After backfilling, weld the gaps in the steel casing to seal them. After completing one section, raise the operating platform to start the next section until the removal is complete. Note: Before cutting the steel casing, calculate and determine whether to install temporary internal supports inside the steel casing based on the stratum and water pressure conditions. S5: Lift out the operating platform and equipment inside the steel sleeve, remove the steel casing. When removing the steel sleeve, backfill and remove it simultaneously to prevent the hole from collapsing. S6: Construction of shield tunneling through diaphragm wall.

2. The method for breaking up a steel joint in a diaphragm wall according to claim 1, characterized in that, In step S1, the method of soil reinforcement outside the location of the diaphragm wall steel joint is selected according to the stratum conditions, and one or more of the following methods are adopted: high-pressure jet grouting, mixing piles, sleeve valve pipe grouting, and drilling and injection machine grouting reinforcement.

3. The method for removing the steel joint of a diaphragm wall according to claim 1, characterized in that, The range of the solidified body in step S1, the thickness of the bottom sealing in step S2, and the range of the grouting reinforcement on the back of the diaphragm wall in step S3 are determined according to the stratum and water pressure.

4. The method for breaking up a steel joint in a diaphragm wall according to claim 1, characterized in that, In step S2, the diameter of the steel casing is 2m, and it can be adjusted according to construction needs.

5. The method for removing a steel joint in a diaphragm wall according to claim 1, characterized in that, In step S3, the soil behind the diaphragm wall is reinforced by grouting. Grouting can be done using grouting pipes or drilling and grouting machines depending on the construction conditions. The grouting holes are arranged along both sides of the steel joint. When grouting is done using grouting pipes, the grouting pipes should be removed after grouting is completed.

6. The method for breaking up a steel joint in a diaphragm wall according to claim 1, characterized in that, In step S3, when the bottom of the diaphragm wall steel joint is located within the shield tunneling area, grouting reinforcement is required for the bottom area of ​​the diaphragm wall.

7. The method for removing the steel joint of a diaphragm wall according to claim 1, characterized in that, In step S4, the length of each segment for the steel sleeve removal, diaphragm wall steel demolition, plain concrete backfilling, and steel casing welding and sealing operations shall not exceed 1m.

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