Protection structure of existing subway shield tunnel

Abstract

The utility model discloses a protection structure of an existing metro shield tunnel. The protection structure comprises a municipal road structural slab arranged above a metro shield tunnel area, underground diaphragm walls located on the two sides of the metro shield tunnel and a plurality of sets of cast-in-situ bored piles arranged between the two underground diaphragm walls. The municipal road structural plate is arranged above the cast-in-situ bored piles, the upper portion of at least one underground diaphragm wall is connected with a side plate of the municipal road structural plate, a right angle is formed at the joint of the inner side of the underground diaphragm wall and the side plate of the municipal road structural plate, and an underground diaphragm wall cattle foot is arranged at the right angle. The underground diaphragm wall and the cast-in-situ bored piles are vertically arranged on the ground. The influence of municipal road sinking tunnel construction on the existing urban subway tunnel section is reduced, and safe and stable operation of the existing urban subway tunnel is effectively guaranteed.

Description

Technical Field

[0001] The utility model belongs to the technical field of urban traffic road construction, and particularly relates to a protection structure for an existing subway shield tunnel. Background Art

[0002] With the large-scale construction of urban municipal engineering and subway engineering, the situation where newly built roads intersect with existing subway tunnels is gradually increasing. To improve the development and utilization rate of underground space, it is usually chosen to build the subway under the municipal road. However, when the municipal road needs to be widened or renovated, construction and load-bearing need to be carried out above or on the side above the existing subway tunnel, which will have a huge impact on the existing operating subway. For example, when building a sunken tunnel for a municipal road above an existing subway, three problems will occur:

[0003] 1. When constructing the retaining structure of the sunken tunnel for the municipal road, it will extend into the ground and squeeze the surrounding soil, affecting the displacement or deformation of the existing subway.

[0004] 2. When excavating and constructing the sunken tunnel for the municipal road, it will reduce the ballast above the existing subway tunnel, affecting the operation stability of the subway shield tunnel. In severe cases, it will cause the floating deformation of the subway tunnel.

[0005] 3. After the sunken tunnel for the municipal road is completed, the vehicle vibration load is transmitted to the soil through the road surface and then spreads to the existing subway, which will apply additional pressure to the existing subway tunnel and cause irreversible deformation.

[0006] The above three problems will all affect the structure and operation safety of the existing subway shield tunnel. Therefore, in view of the above problems, a protection structure for an existing subway shield tunnel is proposed to solve the above problems. Content of the Utility Model

[0007] To solve the above problems, the utility model provides a protection structure for an existing subway shield tunnel, so as to reduce the influence of the construction of the sunken tunnel for the municipal road on the existing urban subway tunnel section and effectively ensure the safe and stable operation of the existing urban subway tunnel.

[0008] The following is the specific scheme of the utility model:

[0009] A protection structure for an existing subway shield tunnel, the protection structure includes a municipal road structural slab arranged above the subway shield tunnel area, diaphragm walls located on both sides of the subway shield tunnel, and multiple groups of bored cast-in-place piles arranged between the two diaphragm walls. The municipal road structural slab is arranged above the bored cast-in-place piles. The municipal road structural slab includes a top plate, a bottom plate, and two side plates. The top plate and the bottom plate are both arranged parallel to the planned ground. The height of the top plate is lower than the height of the planned ground. The side plates are arranged vertically to the planned ground. The upper end of the side plate is connected to one end of the top plate, and the lower end of the side plate is connected to the end of the bottom plate on the same side as the top plate. A support plate is also arranged between the top plate and the bottom plate; The upper part of at least one diaphragm wall is connected to the side plate of the municipal road structural slab. The diaphragm wall and the bored cast-in-place piles are both arranged vertically to the planned ground.

[0010] Further, a retaining wall is arranged at the top of the diaphragm wall.

[0011] Further, a drainage ditch is arranged on the outer side of the retaining wall.

[0012] Further, at least one group of bored cast-in-place piles is arranged between the left subway tunnel line and the right subway tunnel line of the subway shield tunnel.

[0013] Further, the top plate of the municipal road structural slab is a detachable structure.

[0014] Further, a plain concrete wall can be arranged between the diaphragm wall and the side plate of the municipal road structural slab.

[0015] Further, a diaphragm wall corbel is arranged on the inner side of the upper part of the diaphragm wall, and the municipal road structural slab is installed on the diaphragm wall corbel.

[0016] Further, the diaphragm wall corbel can be replaced with a bored cast-in-place pile.

[0017] Compared with the prior art, the beneficial effects of the present utility model are as follows:

[0018] The present utility model provides a protection structure for an existing subway shield tunnel. Through the support system, the construction of the municipal road is effectively isolated, the disturbance of the soil body during tunnel construction is reduced, the influence of soil movement caused by construction on the structure of the existing subway shield tunnel is reduced, and the structural stability and operation safety of the existing subway tunnel are ensured. Description of the Drawings

[0019] Figure 1 It is a structural diagram of the protection structure of the existing subway shield tunnel in an embodiment;

[0020] Figure 2 For Figure 1Enlarged view of structure a;

[0021] Figure 3 Ground plan of the protection structure of an existing subway shield tunnel in an embodiment;

[0022] Figure 4 Structural diagram of the protection structure of an existing subway shield tunnel in another embodiment.

[0023] In the figure: 1, diaphragm wall; 2, corbel of diaphragm wall; 3, bored cast-in-place pile; 4, structural slab of municipal road; 5, right line of subway tunnel; 6, left line of subway tunnel; 7, retaining wall; 8, drainage ditch; 9, plain concrete wall. Detailed implementation manners

[0024] Next, the technical solutions in the embodiments of the present utility model will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present utility model. Obviously, the described embodiments are only a part of the embodiments of the present utility model, rather than all of the embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present utility model.

[0025] Among them, the orientation or positional relationship indicated by terms such as "top", "bottom", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. is based on the orientation or positional relationship shown in the accompanying drawings. It is only for the convenience of describing the present utility model 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 therefore cannot be construed as a limitation to the present utility model; in addition, unless otherwise clearly specified and limited, terms such as "connection" and "communication" should be understood in a broad sense. For example, they can be directly connected, or indirectly connected through an intermediate medium, and can be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present utility model can be understood in specific situations.

[0026] Embodiment 1

[0027] Figure 1 The structural diagram of the protection structure of an existing subway shield tunnel in an embodiment is disclosed, Figure 3 The ground plan of the protection structure of an existing subway shield tunnel in an embodiment is disclosed.

[0028] This embodiment discloses a protection structure for an existing subway shield tunnel, which includes a municipal road structural slab 4 arranged above the subway shield tunnel area, diaphragm walls 1 located on both sides of the subway shield tunnel, and multiple groups of bored cast-in-place piles 3 arranged between the two diaphragm walls 1. Among them, the diaphragm walls 1 are used to block the deformation of the subway tunnel caused by the change of soil pressure around the subway, and at the same time, the diaphragm wall support also has a good effect of preventing water leakage in the foundation pit; the municipal road structural slab 4 is arranged above the bored cast-in-place piles 3. The municipal road structural slab 4 includes a top plate, a bottom plate, and two side plates. The top plate and the bottom plate are both parallel to the planned ground. The height of the top plate is lower than the height of the planned ground. The side plates are vertically arranged on the planned ground. The upper end of the side plate is connected to one end of the top plate, and the lower end of the side plate is connected to the end of the bottom plate on the same side as the top plate. A support plate is also arranged between the top plate and the bottom plate, and the support plate is arranged at the middle position between the top plate and the bottom plate; the upper part of at least one diaphragm wall 1 is connected to the side plate of the municipal road structural slab 4, and a right angle is formed at the connection between the inner side of the upper part of the diaphragm wall 1 and the side plate of the municipal road structural slab 4. An underreamed footing 2 of the diaphragm wall is arranged at this right angle, and the municipal road structural slab 4 is installed on the underreamed footing of the diaphragm wall. The diaphragm walls 1 and the bored cast-in-place piles 3 are both vertically arranged on the planned ground.

[0029] In this embodiment, as Figure 2 , a retaining wall 7 is arranged at the top of the diaphragm wall 1, and a drainage ditch 8 is arranged on the outer side of the retaining wall 7.

[0030] In this embodiment, at least one group of bored cast-in-place piles 3 is arranged between the left line 6 of the subway tunnel and the right line 5 of the subway tunnel of the subway shield tunnel. The bored cast-in-place piles 3 are used to bear the permanent vertical load of the upper municipal road sinking tunnel structure.

[0031] In this embodiment, the number of bored cast-in-place piles 3 in each group is at least three, and multiple bored cast-in-place piles 3 are arranged along the direction of the subway shield tunnel.

[0032] In this embodiment, the top plate of the municipal road structural slab 4 is a detachable structure. The municipal road structural slab 4 is arranged above the bored cast-in-place piles 3, and is used to distribute live loads such as the traffic load of the municipal road, and together with the bored cast-in-place piles 3, it forms a portal protection structure to prevent the permanent vertical load of the upper municipal road structure from being directly transmitted to the existing subway shield tunnel.

[0033] This embodiment also provides a construction method for the protection structure of an existing subway shield tunnel, and the specific steps are as follows:

[0034] Step 1, construction of the diaphragm wall 1:

[0035] Step 101, measurement and setting out: Determine the construction position of the diaphragm wall 1, and the construction accuracy needs to be ensured;

[0036] Step 102, Guide Wall Excavation and Pouring: Pour with concrete of grade C25, with a wall thickness of 200 mm;

[0037] Step 103, Hydraulic Grab Grooving and Excavating: The grooving machine shall not be lifted or dropped suddenly to prevent the formation of a negative pressure area in the groove and the occurrence of groove collapse;

[0038] Step 104, Scanning the Hole and Cleaning the Groove Joint: Use a specially made scraper with a 30-mm steel plate, installed on the grab of the grooving machine, to forcibly remove the flowing concrete attached to the H-shaped steel at the joint;

[0039] Step 105, Lifting and Placing the Steel Cage: When inserting the steel cage, align the steel cage with the center of the groove and insert it vertically and accurately into the groove. When the steel cage enters the groove, align the lifting point center with the center of the groove and lower it slowly to prevent collision with the groove wall;

[0040] Step 106, Lifting and Placing the Conduit: The embedded grouting pipe is made of a steel pipe with a diameter of Φ50 mm and a thickness of t = 3 mm, and is firmly connected by screw threads;

[0041] Step 107, Pouring Concrete: Pour the concrete from bottom to top at a uniform speed to ensure overall stability.

[0042] Step 2, Construction of Bored Cast-In-Place Pile 3:

[0043] Step 201, Surveying and Positioning: Use the polar coordinate method to lay out each pile hole. To ensure accurate layout, each pile must be positioned three times;

[0044] Step 202, Burying the Casing: The casing is generally fabricated from steel plates 4 - 10 mm thick, with a height of about 2 m. The inner diameter of the casing is 200 mm larger than the drill bit diameter and 0.5 m higher than the ground;

[0045] Step 203, Drilling and Hole Formation: When the drilling rig is accurately positioned, start drilling. The penetration per round trip during drilling is controlled at about 50 cm. At the beginning, slow down the rotary drilling speed, and pay attention to lowering the bucket steadily and lifting the bucket slowly;

[0046] Step 204, Hole Cleaning: Use the positive circulation or air compressor for hole cleaning. The steel cage should be inserted into the hole preferably before hole cleaning. If the pump suction reverse circulation hole cleaning method is used, the steel cage is generally inserted into the hole after hole cleaning;

[0047] Step 205, Installing the Steel Cage: The steel cage is installed by lifting with a large crane and aligned with the center of the pile hole and then placed into the hole. If the pile hole is relatively deep, the steel cage should be fabricated in sections and butt - jointed at the hole opening;

[0048] Step 206, Embedding the Sonic Logging Tube: When fabricating each section of the steel cage, cooperate with the sectional embedding of the sonic logging tube. The sonic logging tube is made of galvanized pipe and PVC pipe is not recommended. During the process of hoisting and lowering the sectional steel cage, connect the sectional sonic logging tubes through sleeves;

[0049] Step 207, underwater concrete pouring: The designed strength grade of the pile body concrete is underwater C35, and commercial concrete is used. During the underwater concrete pouring process, construction shall be carried out strictly in accordance with the specifications and design requirements.

[0050] Step 3, construction of the municipal road structural slab 4:

[0051] Step 301, formwork installation: The side formwork adopts wooden formwork and square timber backing, cooperates with tie rods and double butterfly buckle double nuts, and uses steel pipes as inclined braces to reinforce the outside formwork; the top formwork adopts full hall frame vertical poles with a spacing of 800×800; the vertical and horizontal pole step distance is 1500, and the floor sweeping pole is 200 higher than the floor surface. The platform slab support is leveled by top supports, and 50×100 wooden square timbers should be laid vertically on the top supports to support the formwork;

[0052] Step 302, steel bar binding: Spacers should be set between the steel bars and the formwork. The spacers should be tied tightly to the steel bars and staggered from each other; if there are several layers of steel bars in the component and the upper layer is heavier, special steel bar supports can be used during installation; the intersections of the steel bars should be tied firmly with iron wire, and if necessary, they can also be welded firmly with spot welding;

[0053] Step 303, concrete pouring: To reduce the self-shrinkage of the structural concrete and avoid structural cracking caused by uneven settlement of the structure, strictly control the longitudinal main structure segmentation and the vertical layered pouring construction sequence. The buried section is longitudinally divided into sections at a spacing of 25 meters and combined with the design deformation joints as one section. The buried section is vertically poured in three layers (bottom slab → wall → top slab) for the main structure. The horizontal construction joint is set at 300 mm above the bottom slab axil angle and 300 mm below the top slab axil angle; the U-shaped groove section is longitudinally and vertically poured in two layers (bottom slab, wall → wall), and the horizontal construction joint is set at 1800 mm above the bottom slab axil angle.

[0054] After the diaphragm wall 1, diaphragm wall corbel 2, bored pile 3, and municipal road structural slab 4 are all constructed, a U-shaped protection structure is formed. This structure can effectively isolate and reduce the disturbance of the soil body during the construction of the municipal road sinking tunnel, and ensure the structural stability and operation safety of the existing subway tunnel.

[0055] Embodiment 2

[0056] Figure 4 The structural diagram of the protection structure of the existing subway shield tunnel of an embodiment is disclosed.

[0057] In this embodiment, the upper part of the left diaphragm wall 1 is connected to the side plate of the municipal road structural slab 4, and a right angle is formed at the connection between the inner side of the diaphragm wall 1 and the side plate of the municipal road structural slab 4. At least one group of bored piles 3 is arranged at this right angle.

[0058] In this embodiment, a plain concrete wall 9 is arranged between the right diaphragm wall 1 and the side plate of the municipal road structural slab 4. Its connection with the municipal road structural slab 4 can play a certain supporting role and prevent the diaphragm walls 1 on both sides from converging and deforming inward.

[0059] In the above specific embodiments, the purpose, technical solution and beneficial effects of the present utility model have been further described in detail. It should be understood that the above are only specific embodiments of the present utility model and are not used to limit the present utility model. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present utility model shall be included within the protection scope of the present utility model.

Claims

1. A protective structure for an existing subway shield tunnel, characterized in that: The protective structure comprises a municipal road structure plate (4) arranged above the subway shield tunnel area, underground continuous walls (1) located on both sides of the subway shield tunnel, and a plurality of bored cast-in-place piles (3) arranged between the two underground continuous walls (1); the municipal road structure plate (4) is arranged above the bored cast-in-place piles (3), the municipal road structure plate (4) comprises a top plate, a bottom plate and two side plates, the top plate and the bottom plate are both arranged parallel to the planned ground, the height of the top plate is lower than the height of the planned ground, the side plates are arranged vertically to the planned ground, the upper end of the side plate is connected to one end of the top plate, the lower end of the side plate is connected to one end of the bottom plate on the same side as the top plate, and a support plate is also arranged between the top plate and the bottom plate; the upper part of at least one of the underground continuous walls (1) is connected to the side plate of the municipal road structure plate (4), and the underground continuous wall (1) and the bored cast-in-place piles (3) are both arranged vertically to the planned ground.

2. The protective structure of an existing subway shield tunnel as claimed in claim 1, characterized in that: A retaining wall (7) is arranged on the top of the underground continuous wall (1).

3. The protective structure of an existing subway shield tunnel as claimed in claim 2, characterized in that: A drainage ditch (8) is provided on the outer side of the retaining wall (7).

4. The protective structure of an existing subway shield tunnel as claimed in claim 1, characterized in that: At least one group of bored cast-in-place piles (3) is arranged between a left subway tunnel line (6) and a right subway tunnel line (5) of a subway shield tunnel.

5. The protective structure of an existing subway shield tunnel as claimed in claim 1, characterized in that: The top plate of the municipal road structural plate (4) is a removable structure.

6. The protective structure of an existing subway shield tunnel as claimed in claim 1, characterized in that: A plain concrete wall (9) may be provided between the underground continuous wall (1) and the side plate of the municipal road structure plate (4).

7. The protective structure of an existing subway shield tunnel as claimed in claim 1, characterized in that: An underground continuous wall foot (2) is provided on the inner side of the upper part of the underground continuous wall (1), and the municipal road structure plate (4) is installed on the underground continuous wall foot (2).

8. The protective structure of an existing subway shield tunnel as claimed in claim 7, characterized in that: The underground continuous wall bull feet (2) can be replaced by bored cast-in-place piles (3).

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