Construction method for foundation pit of existing station

Abstract

The present invention relates to a foundation pit construction method for an existing station, comprising the following steps: excavating a foundation pit on one side of the main structure of the existing station; wherein the main structure of the existing station includes a top structure and a wall structure, the top structure is connected to the side of the wall structure close to the ground, and a steel bar connector is built into the top structure; when digging down to the bottom of the top structure, a connection port is excavated at the connection between the wall structure and the top structure until the steel bar connector is exposed; a stabilizing member is cast at the connection port to connect the steel bars in the stabilizing member and the steel bar connector; wherein one end of the wall structure close to the ground abuts against one side of the stabilizing member; and the foundation pit is continued to be excavated until the target foundation pit depth. One end of the wall structure abuts against one side of the stabilizing member, and the stabilizing member can provide stable support for the wall structure to avoid collapse of the wall structure close to the ground during the digging process. The structural stability and reliability of the existing station are then guaranteed.

Description

Technical Field

[0001] The invention relates to the technical field of subway building construction, in particular to a foundation pit construction method for an existing station. Background Art

[0002] The purpose of building a rail transit network is to ensure smooth and fast travel for citizens and to provide passengers with a safe, convenient and comfortable environment. With the continuous expansion of urban transportation networks, the status of transfer stations has become increasingly prominent and has become a major factor affecting rail transit efficiency and service levels. With the continuous development of urban rail transit, especially for large cities (Shenzhen, Shanghai, Guangzhou, etc.), more and more subway stations have been put into operation, and there are more and more stations that transfer with existing operating lines in the newly planned and designed transportation lines. As transfer stations implemented later, the ground-connected walls and station roof soil of existing operating stations are often processed, which will not only affect the existing operating lines, but also the main body of the existing stations. Summary of the invention

[0003] Based on this, it is necessary to provide a foundation pit construction method for an existing station in order to address the issues that may affect the existing station body during the above-mentioned construction process.

[0004] A foundation pit construction method for an existing station comprises the following steps:

[0005] A foundation pit is excavated on one side of the existing station main structure; wherein the existing station main structure includes a top structure and a wall structure, the top structure is connected to a side of the wall structure close to the ground, and a steel bar connector is built into the top structure;

[0006] When digging down to below the top structure, a connection opening is excavated at the connection between the wall structure and the top structure until the steel bar connector is exposed;

[0007] Casting a stabilizing member at the connection port, connecting the steel bars in the stabilizing member to the steel bar connector; wherein one end of the wall structure close to the ground abuts against one side surface of the stabilizing member;

[0008] Continue to dig the foundation pit until the target foundation pit depth is reached.

[0009] In one embodiment, excavating a foundation pit on one side of the existing station main structure includes:

[0010] The top structure includes a top plate and a top beam, the top beam and the wall structure are respectively located on two opposite sides of the top plate and in the same vertical plane, the top plate is equipped with the steel bar connector; the steel bar connector is located at the connection between the top plate and the wall structure.

[0011] In one embodiment, a foundation pit is excavated on one side of the existing station main structure, including:

[0012] The wall structure includes a sealing wall and a diaphragm wall. The diaphragm wall and the sealing wall are arranged closely. One end of the sealing wall is connected to the top plate. The steel bar coupler is located at the connection between the top plate and the sealing wall. The connection opening is drilled on the diaphragm wall.

[0013] In one embodiment, before excavating down to below the top layer structure, it further includes:

[0014] A capping beam is constructed at one end of the wall structure close to the ground. The length direction of the capping beam is the same as the length direction of the wall structure.

[0015] In one embodiment, after constructing a capping beam at one end of the wall structure close to the ground, it further includes:

[0016] A first support member is arranged on one side of the capping beam. The first support member is used to stabilize the soil layer structure.

[0017] In one embodiment, a stabilizing member is cast at the connection opening, and the steel bars in the stabilizing member are connected to the steel bar coupler. After that, it includes:

[0018] When the structural strength of the stabilizing member reaches 80% of its design strength, continue to excavate the foundation pit.

[0019] In one embodiment, continuing to excavate the foundation pit includes:

[0020] While excavating the foundation pit, break the diaphragm wall on the side of the stabilizing member facing away from the ground.

[0021] In one embodiment, after breaking the diaphragm wall on the side of the stabilizing member facing away from the ground, it further includes:

[0022] A second support member is arranged. One end of the second support member abuts against the sealing wall, and the other end of the second support member abuts against the inner wall of the foundation pit.

[0023] In one embodiment, casting a stabilizing member at the connection opening includes:

[0024] The length of the stabilizing member is greater than the thickness of the diaphragm wall; and / or

[0025] The shape of the stabilizing member is a frustum shape.

[0026] Specifically, the stabilizing member includes a boss portion and a main body portion. The boss portion is cast on one end of the main body portion. One side surface of the diaphragm wall abuts against one side surface of the main body portion, and the other side surface of the diaphragm wall abuts against the other side surface of the boss portion. The steel bars in the main body portion are connected to the steel bar couplers.

[0027] Specifically, the length of the main body portion is greater than or equal to 1.5 m, and the thickness of the main body portion is greater than or equal to the thickness of the top plate; the thickness of the boss portion is greater than or equal to 0.3 m, and the length of the boss portion is greater than or equal to 0.7 m.

[0028] For the above-mentioned construction method of the foundation pit of the existing station, when expanding the existing station, it is necessary to excavate the foundation pit on one side of the main body of the existing station. When the foundation pit is excavated to below the top structure, after opening a connection opening in the wall structure and exposing the steel bar couplers reserved in the top structure, a stabilizing member is formed by pouring at the connection opening. At the same time, the steel bars in the stabilizing member are connected to the steel bar couplers, and the steel bar couplers are arranged in the top structure, so that the stabilizing member can obtain the stable support of the top structure. At the same time, since the stabilizing member is cast at the connection opening and one end of the wall structure abuts against one side surface of the stabilizing member, the stabilizing member can provide stable support for the wall structure and prevent the wall structure near the ground end from collapsing during the excavation process. Thereby ensuring the structural stability and reliability of the existing station.

[0029] Before the excavation of the foundation pit, an area close to the main structure of the existing station and also a non-municipal road can be selected for excavation, thus avoiding the impact on municipal road traffic and expanding the existing station while ensuring the safety of the main structure of the existing station. Further improving the practicability and reliability of this construction method. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] The drawings forming a part of this application are used to provide a further understanding of the present invention. The schematic embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation to the present invention.

[0031] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for the description of the embodiments will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0032] Figure 1 It is a schematic structural diagram of the main structure of the existing station in an embodiment;

[0033] Figure 2 For Figure 1A schematic diagram of the structure of an existing station after foundation pit construction in the embodiment.

[0034] The components in the figure are marked as follows:

[0035] 10. Main structure of the existing station; 100. Top structure; 110. Top plate; 111. Steel bar connector; 120. Top beam; 200. Wall structure; 210. Ground-connected wall; 211. Connection port; 220. Blocking wall; 300. Stabilizer; 400. Crown beam. DETAILED DESCRIPTION

[0036] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific embodiments of the present invention are described in detail below in conjunction with the accompanying drawings. In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without violating the connotation of the present invention, so the present invention is not limited by the specific embodiments disclosed below.

[0037] See also Figure 1 and Figure 2 In one embodiment, a foundation pit construction method for an existing station includes:

[0038] A foundation pit construction method for an existing station comprises the following steps:

[0039] S100, excavating a foundation pit on one side of an existing station main structure 10; wherein the existing station main structure 10 includes a top structure 100 and a wall structure 200, the top structure 100 is connected to a side of the wall structure 200 close to the ground, and the top structure 100 is provided with a steel bar connector 111;

[0040] S200, when digging down to below the top structure 100, a connection opening 211 is excavated at the connection between the wall structure 200 and the top structure 100 until the steel bar connector 111 is exposed;

[0041] S300, casting a stabilizing member 300 at the connection port 211, connecting the steel bars in the stabilizing member 300 and the steel bar connector 111; wherein one end of the wall structure 200 close to the ground contacts a side surface of the stabilizing member 300;

[0042] S400, continue digging the foundation pit until the target foundation pit depth.

[0043] The above-mentioned construction method for the foundation pit of the existing station, when expanding the existing station, requires excavating a foundation pit on one side of the main body of the existing station. When the foundation pit is excavated to below the top structure 100, by cutting a connection opening 211 in the wall structure 200, after exposing the steel bar coupler 111 reserved in the top structure 100, pouring is carried out at the connection opening 211 to form a stabilizing member 300. At the same time, the steel bars in the stabilizing member 300 are connected to the steel bar coupler 111, and the steel bar coupler 111 is arranged in the top structure 100, so that the stabilizing member 300 can obtain the stable support of the top structure 100. At the same time, since the stabilizing member 300 is poured at the connection opening 211, one end of the wall structure 200 abuts against one side surface of the stabilizing member 300, and the stabilizing member 300 can provide stable support for the wall structure 200, avoiding the collapse of the wall structure 200 at the end close to the ground during the excavation process. Thereby ensuring the structural stability and reliability of the existing station.

[0044] Before the excavation of the foundation pit, an area close to the main structure 10 of the existing station and also a non-municipal road can be selected for excavation, thus avoiding the impact on municipal road traffic and the operation of the existing station, and the existing station can also be expanded while ensuring the safety of the main structure 10 of the existing station. Further improving the practicability and reliability of this construction method.

[0045] In one embodiment, excavating a foundation pit on one side of the main structure 10 of the existing station includes:

[0046] The top structure 100 includes a roof slab 110 and a coping beam 120. The coping beam 120 and the wall structure 200 are respectively located on two opposite sides of the roof slab 110 and are in the same vertical plane. The steel bar coupler 111 is built in the roof slab 110; the steel bar coupler 111 is located at the connection between the roof slab 110 and the wall structure 200.

[0047] The coping beam 120 can provide structural support for the roof slab 110, and the steel bar coupler 111 in the roof slab 110 can provide structural support for the stabilizing member 300, and then transfer the force of the stabilizing member 300 into the force on the coping beam 120 and the roof slab 110. Ensuring the reasonable force of the overall structure of the existing station and improving the safety and stability of the existing station during the construction process.

[0048] In one embodiment, excavating a foundation pit on one side of the main structure 10 of the existing station includes:

[0049] The wall structure 200 includes a sealing wall 220 and a diaphragm wall 210. The diaphragm wall 210 and the sealing wall 220 are arranged closely. One end of the sealing wall 220 is connected to the top plate 110. The steel bar coupler 111 is located at the connection between the top plate 110 and the sealing wall 220. The connection opening 211 is formed on the diaphragm wall 210.

[0050] The stabilizing member 300 is inserted into the connection opening 211 and connected to the steel bar coupler 111. One end of the diaphragm wall 210 close to the ground can abut against the stabilizing member 300, so that the stabilizing member 300 can provide stable support for the diaphragm wall 210, avoiding the diaphragm wall 210 close to the ground from collapsing underground during the subsequent excavation of the diaphragm wall 210. The stabilizing member 300 distributes the load to the top structure through the steel bar coupler 111, so that the main structure 10 of the existing station bears the load of the stabilizing member 300, further ensuring the reliability and safety of this construction method.

[0051] In one embodiment, before excavating below the top structure 100, it further includes:

[0052] Construct a capping beam 400 on one end of the wall structure 200 close to the ground. The length direction of the capping beam 400 is the same as the length direction of the wall structure 200.

[0053] Specifically, construct a capping beam 400 on one end of the diaphragm wall 210 close to the ground. The length direction of the capping beam 400 is the same as the length direction of the wall structure 200.

[0054] In one embodiment, the width dimension of the capping beam 400 is greater than or equal to the thickness of the diaphragm wall 210. The height dimension of the capping beam 400 is the same as the width dimension of the capping beam 400.

[0055] In one embodiment, after constructing a capping beam 400 on one end of the wall structure 200 close to the ground, it further includes:

[0056] A first support member is arranged on one side of the capping beam 400. The first support member is used to stabilize the soil layer structure.

[0057] The first support member stabilizes the soil layer structure, ensuring that the soil layer will not collapse into the foundation pit during construction, and thus ensuring the safety of construction.

[0058] In one embodiment, the stabilizing member 300 is formed by pouring at the connection opening 211, and the steel bars in the stabilizing member 300 are connected to the steel bar coupler 111. After that, it includes:

[0059] When the structural strength of the stabilizing member 300 reaches 80% of its design strength, continue to excavate the foundation pit.

[0060] After the stabilizer 300 meets the strength requirements, continue the construction to ensure the stability and structural safety of the wall structure 200.

[0061] In one embodiment, continuing to excavate the foundation pit includes:

[0062] While excavating the foundation pit, break the diaphragm wall 210 on the side of the stabilizer 300 facing away from the ground.

[0063] The diaphragm wall 210 is broken as it is excavated during the process of excavating the foundation pit.

[0064] In one embodiment, after breaking the diaphragm wall 210 on the side of the stabilizer 300 facing away from the ground, it includes:

[0065] Set a second support member, one end of the second support member abuts against the plugging wall 220, and the other end of the second support member abuts against the inner wall of the foundation pit.

[0066] The second support member can further ensure the stability and safety of the foundation pit structure and the main structure 10 of the existing station.

[0067] In one implementation, pouring the stabilizer 300 at the connection port 211 includes:

[0068] The length of the stabilizer 300 is greater than the thickness of the diaphragm wall 210.

[0069] The length of the stabilizer 300 being greater than the thickness of the diaphragm wall 210 can ensure that the diaphragm wall is completely abutted on the stabilizer 300. At the same time, the stabilizer 300 can also be stably connected to the steel bar coupler 111, thereby ensuring the safety and reliability of the overall construction structure.

[0070] In one embodiment, the shape of the stabilizer 300 is a convex platform shape.

[0071] Specifically, the stabilizer 300 includes a convex platform part and a main body part. The convex platform part is poured on one end of the main body part. One side surface of the diaphragm wall 210 abuts against one side surface of the main body part, and the other side surface of the diaphragm wall 210 abuts against the other side surface of the convex platform part. The steel bars in the main body part are connected to the steel bar coupler 111. It improves the contact area between the stabilizer 300 and the diaphragm wall 210, and improves the support stability of the stabilizer 300 to the diaphragm wall 210. It avoids the collapse of the diaphragm wall 210, and further improves the structural safety and stability of the existing station.

[0072] Specifically, the length of the main body part is greater than or equal to 1.5 m, and the thickness of the main body part is greater than or equal to the thickness of the top plate 110; the thickness of the boss part is greater than or equal to 0.3 m, and the length of the boss part is greater than or equal to 0.7 m.

[0073] Specifically, the height of the connection port 211 is greater than or equal to the thickness of the top plate 110.

[0074] The purpose of building the rail transit network is to ensure the smoothness and speed of citizens' travel, and to provide a safe, convenient and comfortable environment for passengers. With the continuous expansion of the urban traffic network, the status of transfer stations has become increasingly prominent, becoming the main factor affecting the efficiency and service level of rail transit. With the continuous development of urban rail transit, especially for large cities (such as Shenzhen, Shanghai, Guangzhou, etc.), there are more and more subway stations that have been put into operation, and there are also more and more stations that transfer with the stations of existing operating lines in the newly planned and designed traffic lines in the later stage. As the transfer stations implemented in the later stage often need to deal with the diaphragm wall and the soil body of the station top plate of the existing operating station, in order to minimize the impact on the existing operating line, reasonable design and implementation measures are particularly important.

[0075] The treatment schemes for the diaphragm wall 210 and the soil body of the station top plate 110 of the already operating station during the implementation of the later-stage project of the existing transfer station are mainly divided into three types. The first type is to use the existing diaphragm wall 210 to retain soil during excavation and layer-by-layer chisel the interface diaphragm wall 210 during the main body backfilling; the second type is to slope-treat the soil body of the existing station top plate 110 and break the diaphragm wall 210 as it is excavated. The first type is not very applicable to stations with a relatively large storey height, and there is a relatively large risk during the breaking of the diaphragm wall 210; the second type is not applicable to stations without conditions for slope treatment, and there are usually municipal pipelines on the top plate 110 of general stations, and the pipelines often need to be temporarily relocated during slope excavation, resulting in an increase in the construction period and cost. No matter which treatment method, there are respective limitations such as applicable environments, self-conditions, applicable projects, etc. The existing construction schemes have respective limitations such as applicable environments, self-conditions, applicable projects, etc., so it is necessary to study a new treatment method to solve the actual problem of affecting the main body of the existing station. The construction method of the present application is safe and reliable, can avoid the impact on municipal road traffic and the operation of existing stations, and can also expand the existing station while ensuring the safety of the main structure 10 of the existing station.

[0076] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by terms such as "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as a limitation to the present invention.

[0077] In addition, the terms "first" and "second" are only used for descriptive purposes and should not be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include at least one such feature. In the description of the present invention, the meaning of "a plurality of" is at least two, such as two, three, etc., unless otherwise specifically and clearly defined.

[0078] In the present invention, unless otherwise clearly specified and defined, terms such as "mounted", "connected", "connected to", "fixed" should be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or integrated; it may be a mechanical connection or an electrical connection; it may be directly connected or indirectly connected through an intermediate medium, and it may be the communication inside two elements or the interaction relationship between two elements, unless otherwise clearly defined. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0079] In the present invention, unless otherwise clearly specified and defined, the first feature being "on" or "under" the second feature may be that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, the first feature being "above", "over" and "on top of" the second feature may be that the first feature is directly above or obliquely above the second feature, or merely indicates that the first feature has a higher horizontal height than the second feature. The first feature being "under", "beneath" and "underneath" the second feature may be that the first feature is directly below or obliquely below the second feature, or merely indicates that the first feature has a lower horizontal height than the second feature.

[0080] It should be noted that when an element is referred to as "fixed to" or "disposed on" another element, it can be directly on the other element or there may also be an intermediate element. When an element is considered to be "connected to" another element, it can be directly connected to the other element or there may be an intermediate element at the same time. The terms "vertical", "horizontal", "upper", "lower", "left", "right" and similar expressions used herein are for illustrative purposes only and do not represent the only implementation.

[0081] The technical features of the above-described embodiments can be combined arbitrarily. For the sake of brevity of description, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered as the scope described in this specification.

[0082] The above-described embodiments only represent several implementation manners of the present invention, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the invention patent. It should be pointed out that for those of ordinary skill in the art, without departing from the concept of the present invention, several modifications and improvements can be made, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the present invention patent shall be subject to the appended claims.

Claims

1. A construction method for the foundation pit of an existing station, characterized in that, The method comprises the following steps: A foundation pit is excavated on one side of the existing station main structure; wherein the existing station main structure includes a top structure and a wall structure, the top structure is connected to the side of the wall structure close to the ground, the top structure includes a top plate and a top beam, the top beam and the wall structure are respectively located on two opposite sides of the top plate and are located in the same vertical plane, and a steel bar connector is built into the top plate; the wall structure includes a blocking wall and a ground-connected wall, the ground-connected wall and the blocking wall are closely arranged, one end of the blocking wall is connected to the top plate, and the steel bar connector is located at the connection between the top plate and the blocking wall; When digging down to the bottom of the top structure, a connection opening is excavated at the connection between the wall structure and the top structure until the steel bar connector is exposed; a stabilizing member is cast at the connection opening, and the steel bars in the stabilizing member are connected to the steel bar connector; wherein one end of the wall structure close to the ground contacts a side surface of the stabilizing member; The foundation pit is continued to be excavated, and the ground-connected wall of the existing station below the stabilizing member is broken as the excavation progresses until the target foundation pit depth is reached.

2. The construction method of the foundation pit of the existing station according to claim 1, characterized in that, Excavation below the top structure, previously including: A crown beam is constructed on one end of the wall structure close to the ground, and the length direction of the crown beam is consistent with the length direction of the wall structure.

3. The construction method of the foundation pit of the existing station according to claim 2, characterized in that, A cap beam is formed on one end of the wall structure close to the ground, and then the following steps are further included: A first support member is arranged on one side of the cap beam, and the first support member is used to stabilize the soil layer structure.

4. The construction method of the foundation pit of the existing station according to claim 1, characterized in that, Casting a stabilizing member at the connection port, connecting the steel bars in the stabilizing member and the steel bar connector, and then comprising: When the structural strength of the stabilizing member reaches at least 80% of its designed strength, the foundation pit is continued to be excavated.

5. The construction method of the foundation pit of the existing station according to claim 2, wherein, Continue to dig the foundation pit, including: While digging the foundation pit, the ground-connected wall on the side of the stabilizing member facing away from the ground is removed.

6. The construction method of the foundation pit of the existing station according to claim 5, wherein, The ground-connected wall on the side of the stabilizing member facing away from the ground is broken, and then the method includes: A second support member is provided, one end of which abuts against the blocking wall, and the other end of which abuts against the inner wall of the foundation pit.

7. The construction method of the foundation pit of the existing station according to claim 1, characterized in that, The stable parts are cast at the connection ports, including: The length of the stabilizing member is greater than the thickness of the ground-connected wall; and / or The shape of the stabilizing member is a boss shape.

8. The construction method of the foundation pit of the existing station according to claim 7, characterized in that, The stable parts are cast at the connection ports, including: The stabilizing member includes a boss portion and a main body portion, the boss portion is cast on one end of the main body portion, one side surface of the ground-connected wall abuts against one side surface of the main body portion, and the other side surface of the ground-connected wall abuts against the other side surface of the boss portion, and the steel bars in the main body portion are connected to the steel bar connector; the length of the main body portion is greater than or equal to 1.5m, and the thickness of the main body portion is greater than or equal to the thickness of the top plate; the thickness of the boss portion is greater than or equal to 0.3m, and the length of the boss portion is greater than or equal to 0.7m.

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