Reverse construction joint remaining method for side wall of covered and excavated reverse station

Abstract

The invention discloses a cover-excavation top-down station side wall top-down construction joint retention method, which is used for a floor mold retention method and comprises the following steps: excavating a structural plate and a side wall in advance to form a structural outline, reserving reinforcing steel bars in the side wall, backfilling sandy soil at the excavation position of the side wall, and pouring a concrete leveling layer within the range of the structural plate. An isolating layer is arranged on the concrete leveling layer, and structural slabs and side walls are poured synchronously to form structural concrete; and after the structural concrete meets the design strength requirement, excavating the earthwork below the structural concrete, removing the concrete leveling layer, manually chiseling the construction joint, and pouring the side wall concrete below the construction joint through the pouring gate. The invention relates to the technical field of building construction, and can solve the problem that in the prior art, a construction joint of a side wall of a cover-excavation top-down station has a leakage risk.

Description

Technical Field

[0001] The invention relates to the technical field of building construction, and in particular to a method for leaving a reverse construction joint of a side wall of a cover-and-cut reverse construction station. Background Art

[0002] The construction process of the cover-excavation reverse method is: first build the retaining structure and intermediate piles of the foundation pit downward from the ground surface, then excavate the surface soil to the ground elevation of the top plate of the main structure, use the unexcavated soil as a soil mold to cast the top plate and waterproof structure to form the cover plate (i.e. the top plate). After the retaining structure and cover plate are completed, use the floor slabs and structural beams of each layer as the horizontal support of the foundation pit, and excavate and build the main structure layer by layer from top to bottom until the bottom plate.

[0003] The advantage of the cover-excavation reverse construction method is that the top plate construction can be completed as soon as possible, with less impact on ground traffic, and the side wall can form a support system in time during the construction process of the cover-excavation reverse construction method, so that the deformation of the enclosure structure is small. The cover-excavation reverse construction method will form a reverse construction joint at the intersection of the structural plate (including the top plate and floor slab) and the side wall. This construction joint is the main risk of leakage in the side wall.

[0004] Therefore, the construction joint at the node between the side wall and the structural plate is the key point of construction quality control and an important link in controlling water leakage of the side wall. It is necessary to provide a method for retaining the construction joint of the side wall of the cover-excavation reverse construction station, which can solve the problem of leakage risk in the construction joint of the side wall of the cover-excavation reverse construction station in the prior art. Summary of the invention

[0005] The purpose of the present invention is to provide a method for leaving a construction joint of a side wall of a cover-excavation and reverse-construction station, which can solve the problem of leakage risk in the construction joint of the side wall of a cover-excavation and reverse-construction station in the prior art.

[0006] The present invention is achieved in that: A method for retaining a construction joint of a side wall of a cover-and-trenches station is disclosed. The method is used in the cover-and-trenches construction of a ground formwork retention method. The method comprises the following steps: Step 1-1: Dig out the structural outline of the structural slab and side wall in advance. The design position of the construction joint is located below the structural slab, and the steel bars in the side wall above the construction joint are reserved below the design position of the construction joint; Step 1-2: Backfill sand and soil at the excavation position of the side wall, and backfill the sand and soil to the construction joint; Step 1-3: Pour the concrete leveling layer within the structural slab on the ground formwork; Step 1-4: An isolation layer is provided on the concrete leveling layer, the isolation layer extending to the backfilled sand, so that the isolation layer is located between the concrete leveling layer and the structural slab and between the sand and the side wall above the construction joint; Step 1-5: Simultaneously pour the structural slab and the side wall above the construction joint to form structural concrete; Step 1-6: After the structural concrete reaches the design strength requirements, excavate the earth below the structural concrete and remove the concrete leveling layer; Step 1-7: Manually chisel at the reverse joint position of the side wall to form a construction joint; Step 1-8: Carry out waterproofing at the construction joints; Step 1-9: Pour concrete of the side wall below the construction joint through the pouring port.

[0007] In the step 1-1, the steel bars in the side wall are reserved to 500 mm below the design position of the construction joint; In the step 1-1, a first-level joint is reserved at the lower end of the steel bars in the side wall and a steel bar connector is installed; In the step 1-1, the structural plate is a roof plate or a floor plate.

[0008] In the steps 1-2, cement is added to the surface sand of the sandy soil, and an inclined surface is artificially built, and the inclined surface is located at the construction joint; 2% cement is added to the sand, and the inclination angle of the slope is 20°-30°, so that the inclination angle of the construction joint is 20°-30°, and the construction joint is 500mm away from the bottom of the structural plate.

[0009] In the steps 1-3, the concrete strength grade of the concrete leveling layer is not less than C15, and the thickness is not less than 50 mm.

[0010] In the steps 1-8, the composite wall of the cover-excavation reverse construction station adopts the installation method of external waterproofing and internal pasting, the waterproofing membrane is pre-laid on the inner surface of the enclosure structure outside the side wall, and a flexible waterproof layer is arranged between the side wall and the enclosure structure, and is connected to the waterproof layer of the top plate and the bottom plate of the main building structure to form an overall closed external waterproof system; The surface of the construction joint is roughened before pouring the concrete of the side wall below it, and the loose concrete on the surface is cleaned to expose the hard stones. Cement-based penetrating crystallization is applied, water-expanding waterstop strips are set, and the concrete of the side wall below the construction joint is poured in time.

[0011] In the steps 1-9, when pouring concrete at the construction joint, the top surface of the concrete in the pouring opening is higher than the high end of the construction joint by more than 200 mm, and the pouring opening is chiseled out in time after the concrete leveling layer is removed.

[0012] A method for retaining a construction joint of a side wall of a cover-excavation reverse construction station is provided. The method is used in the cover-excavation reverse construction of a plate buckle frame retention method. The method comprises the following steps: Step 2-1: When excavating the soil in the range of the structural plate and side wall, the design position of the construction joint is located below the structural plate. The working surface is excavated to below the design position of the construction joint, and the construction joint template is installed through the side wall buckle frame; Step 2-2: Reserve steel bars within the side wall above the construction joint; Step 2-3: Simultaneously pour the structural slab and the side wall above the construction joint to form structural concrete; Step 2-4: After the structural concrete reaches the design strength requirements, remove the side wall buckle frame and the top plate buckle frame; Step 2-5: Manually chisel at the reverse joint position of the side wall to form a construction joint; Step 2-6: Carry out waterproofing at the construction joints; Step 2-7: Pour concrete of the side wall below the construction joint through the pouring port.

[0013] In the step 2-1, the side wall buckle frame and the top plate buckle frame are connected to form an integrated low formwork buckle frame system; In the step 2-1, the working surface is excavated to 1 m below the designed position of the construction joint; In the step 2-1, the inclination angle of the construction joint template is 20°-30°, so that the inclination angle of the construction joint is 20°-30°, and the construction joint is 500mm away from the bottom of the structural plate; the construction joint template adopts a multi-layer template; In the step 2-1, the structural plate is a roof plate or a floor plate.

[0014] In the step 2-2, the lower end of the steel bar is pressed against the upper surface of the construction joint template, a primary joint is reserved at the lower end of the steel bar and a steel bar connector is installed to connect with the steel bar of the side wall below the construction joint through the primary joint; In the step 2-2, a through hole is formed on the construction joint template, so that the lower end of the steel bar passes through the through hole to the bottom of the construction joint template, and a first-level joint is reserved at the lower end of the steel bar and a steel bar connector is installed for connecting with the steel bar of the side wall below the construction joint through the first-level joint.

[0015] In the steps 2-6, the composite wall of the cover-excavation reverse construction station adopts the installation method of external waterproofing and internal pasting, the waterproofing membrane is pre-laid on the inner surface of the enclosure structure outside the side wall, and a flexible waterproof layer is arranged between the side wall and the enclosure structure, and is connected to the waterproof layer of the top plate and the bottom plate of the main building structure to form an overall closed external waterproof system; The surface of the construction joint is roughened before pouring the concrete of the side wall below it, and the loose concrete on the surface is cleaned to expose the hard stones. Cement-based penetrating crystallization is applied, water-expanding waterstop strips are set, and the concrete of the side wall below the construction joint is poured in time.

[0016] In the steps 2-7, when pouring concrete at the construction joint, the top surface of the concrete in the pouring port is higher than the high end of the construction joint by more than 200 mm, and the pouring port is chiseled out in time after the top plate buckle frame and the side wall buckle frame are removed.

[0017] Compared with the prior art, the present invention has the following beneficial effects: The present invention provides a construction method for retaining construction joints at a structural plate and a side wall based on a ground form retaining method and a disc buckle frame retaining method. The forming and quality treatment effects of the construction joints are good, and the connection of the side wall steel bars above and below the construction joints is convenient. The side wall waterproofing has good integrity, greatly reducing the leakage risk at the construction joints of the side walls of a cover-excavation reverse construction station. The method is easier to construct and has a wide range of applications. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a construction schematic diagram of a method for retaining a construction joint of a side wall of a cover-and-cut reverse-construction station according to the present invention, which is used for a method for retaining a ground formwork; Figure 2 It is a construction schematic diagram of the method for retaining the construction joint of the side wall of the cover-excavation top-down station of the present invention for retaining the buckle frame (the first steel bar reservation method); Figure 3 It is a construction schematic diagram of the method for retaining the construction joint of the side wall of the cover-excavation top-down station of the present invention for retaining the buckle frame (the second steel bar reservation method); Figure 4 It is a schematic diagram of waterproof construction of construction joints of the method for retaining construction joints of the side wall of a cover-excavation reverse construction station of the present invention; Figure 5 The present invention is a schematic diagram of pouring concrete on the side wall below the construction joint of the method for leaving the construction joint of the side wall of the cover-excavation top-down station.

[0019] In the figure, 1 is the top plate, 2 is the side wall, 21 is the steel bar, 22 is the steel bar connector, 3 is the construction joint, 4 is the concrete leveling layer, 5 isolating layer, 6 is the ground formwork, 7 is the sand, 8 is the top plate buckle frame, 9 is the top plate formwork, 10 is the side wall buckle frame, 11 is the construction joint formwork, 12 is the floor slab, 13 is the enclosure structure, 14 is the flexible waterproof layer, 15 is the cement-based penetration crystallization, 16 is the water-expanding waterstop strip, and 17 is the pouring mouth. DETAILED DESCRIPTION

[0020] The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments.

[0021] Please see attached Figure 1A method for retaining construction joints of the side wall of a cover-cut and top-down construction station is used in the cover-cut and top-down construction of the ground formwork retention method, that is, the ground formwork 6 is retained as the earth formwork of the structural plate 1. The ground formwork 6 should meet the rigidity requirements of the structure's deadweight load and construction load, and be solid and flat, with a smooth surface and no cracks.

[0022] When the natural foundation cannot meet the construction requirements of the ground form retention method, ground reinforcement measures can be taken to form a ground form 6 that can meet the construction requirements. Preferably, the surface flatness tolerance of the ground form 6 should be ±5mm, the cross-sectional dimension tolerance should be ±10mm, the axis position tolerance should be ±5mm, and the layer height tolerance should be ±5mm.

[0023] The method for leaving a construction joint in the side wall of a cover-and-excavation reverse construction station comprises the following steps: Step 1-1: The structural outline of the structural plate and the side wall 2 needs to be dug out in advance. The design position of the construction joint 3 is located below the structural plate, and the steel bars 21 in the side wall 2 above the construction joint 3 are reserved below the design position of the construction joint 3.

[0024] Preferably, in step 1-1, the steel bars 21 in the side wall 2 are reserved to 500 mm below the designed position of the construction joint 3.

[0025] Preferably, in the step 1-1, a first-level joint is reserved at the lower end of the steel bar 21 in the side wall 2 and a steel bar connector 22 is installed. At the same time, the steel bar connector 22 needs to be protected, for example, by sealing it with a protective cap, plastic tape, etc., to prevent concrete slurry from entering the sleeve of the steel bar connector 22 during subsequent concrete pouring and affecting the subsequent connection of the steel bars.

[0026] Preferably, in step 1-1, the structural plate is a roof plate 1 or a floor plate 12.

[0027] The construction joint 3 between the top plate 1 and the side wall 2 and the construction joint 3 between the floor plate 12 and the side wall 2 are constructed using the same construction method.

[0028] Step 1-2: Backfill the excavated position of the side wall 2 with sand 7 until the construction joint 3 is reached.

[0029] Preferably, in the steps 1-2, cement is added to the surface sand of the sandy soil 7 and an inclined surface is artificially built, and the inclined surface is located at the construction joint 3.

[0030] The surface sand mixed with cement is shaped to form an inclined surface as the construction joint 3, thereby ensuring the shaping effect of the construction joint.

[0031] Preferably, 2% cement is added to the sand, the inclination angle of the slope is 20°-30°, so that the inclination angle of the construction joint 3 is 20°-30°, and the construction joint 3 is 500 mm away from the bottom of the structural plate.

[0032] The specific inclination angle of the construction joint 3 can be adaptively adjusted according to actual construction requirements.

[0033] Step 1-3: pouring a concrete leveling layer 4 within the structural slab range on the ground formwork 6.

[0034] Preferably, in steps 1-3, the concrete strength grade of the concrete leveling layer 4 is not less than C15, and the thickness is not less than 50 mm.

[0035] Step 1-4: an isolation layer 5 is provided on the concrete leveling layer 4 , and the isolation layer 5 extends to the backfilled sand 7 , so that the isolation layer 5 is located between the concrete leveling layer 4 and the structural slab and between the sand 7 and the side wall 2 above the construction joint 3 .

[0036] The isolation layer 5 is provided to facilitate the subsequent removal of the concrete leveling layer 4. Preferably, the isolation layer 5 can be made of a plastic film or the like, so as to facilitate the isolation of the concrete leveling layer 4 from the structural plate and the concrete of the side wall 2 above the construction joint 3.

[0037] Step 1-5: Synchronously pour the structural slab and the side wall 2 above the construction joint 3 to form structural concrete.

[0038] Step 1-6: After the structural concrete reaches the design strength requirement, excavate the earth below the structural concrete and remove the concrete leveling layer 4.

[0039] Step 1-7: Manually chisel at the reverse joint position of the side wall 2 to form a construction joint 3.

[0040] Please see attached Figure 4 , Step 1-8: Carry out waterproof construction at construction joint 3.

[0041] Preferably, in the steps 1-8, the composite wall of the cover-excavation reverse-construction station is often installed in an externally-protected and internally-pasted manner, and a waterproof membrane of polymer material is pre-laid on the inner surface of the retaining structure 13 outside the side wall 2, and a flexible waterproof layer 14 is arranged between the side wall 2 and the retaining structure 13, and should be connected to the waterproof layer of the top plate 1 and the bottom plate of the main building structure to form an overall closed external waterproof system.

[0042] Preferably, the flexible waterproof layer 14 can be made of waterproof coiled material in the prior art, and the specifications of the waterproof coiled material can be determined according to the waterproof requirements of the actual construction.

[0043] During waterproofing construction, the waterproofing roll material joints at the construction joint 3 should extend beyond the steel bars 21 of the side wall 2 by at least 20 cm. The joints can also be rolled up and fixed, and attention should be paid to later protection.

[0044] Preferably, in the steps 1-8, the surface of the construction joint 3 should be roughened before pouring the concrete of the side wall 2 below it, and the loose concrete on the surface should be cleaned to expose the hard stones, and a cement-based penetrating crystal 15 should be applied, a water-swelling waterstop strip 16 should be set, and the concrete of the side wall 2 below the construction joint 3 should be poured in time.

[0045] When the water-swellable waterstop strip 16 is provided, it should be ensured to be securely fixed.

[0046] Please see attached Figure 5 , step 1-9: pouring concrete of the side wall 2 below the construction joint 3 through the pouring port 17 .

[0047] Before pouring concrete, the pumping equipment should be selected according to the actual situation on site, the pump pipe should be arranged reasonably, and the number of elbows should be reduced. The slump of the pumped concrete at the side wall 2 should be 180~220mm, the spacing between the pouring ports 17 set on the side wall 2 should not be greater than 3m, and the height of the concrete poured at each pouring port 17 should not be greater than 0.5m.

[0048] Preferably, in the steps 1-9, when pouring concrete at the construction joint 3, the top surface of the concrete in the pouring port 17 should be higher than the construction joint 3. Preferably, the top surface of the concrete in the pouring port 17 is higher than the high end of the construction joint 3 by more than 200 mm, and the pouring port 17 is chiseled out in time after the concrete leveling layer 4 is removed.

[0049] Please see attached Figure 2 and attached Figure 3 A method for retaining construction joints in the side walls of a cover-cut and top-down construction station is used in the cover-cut and top-down construction of the disc-locking frame retention method, that is, soil excavation is carried out in the range of the structural plate and the side wall 2, the soil is excavated to the bottom of the structural plate and the top plate formwork 9 is installed through the top plate disc-locking frame 8.

[0050] Installing the top plate formwork 9 through the top plate buckle frame 8 is a conventional formwork support method in this field, and its specific structure and construction process will not be described in detail here.

[0051] The method for leaving a construction joint in the reverse construction of the side wall of a cover-and-excavation reverse construction station comprises the following steps: Step 2-1: When excavating the soil within the range of the structural plate and the side wall 2, the design position of the construction joint 3 is located below the structural plate. The working surface is excavated to below the design position of the construction joint 3, and the construction joint template 11 is installed through the side wall buckle frame 10.

[0052] Preferably, in the step 2-1, the side wall buckle frame 10 and the top plate buckle frame 8 are connected to form an integral low formwork buckle frame system to ensure the integrity and bearing capacity of the low formwork buckle frame system.

[0053] Preferably, in step 2-1, the working surface is excavated to 1 m below the designed position of the construction joint 3.

[0054] Preferably, in step 2-1, the inclination angle of the construction joint template 11 is 20°-30°, so that the inclination angle of the construction joint 3 is 20°-30°, and the construction joint 3 is 500 mm away from the bottom of the structural plate; the construction joint template 11 can adopt a multi-layer template.

[0055] The specific inclination angle of the construction joint 3 can be adaptively adjusted according to actual construction requirements.

[0056] Preferably, in step 2-1, the structural plate is a top plate 1 or a floor plate 12.

[0057] The construction joint 3 between the top plate 1 and the side wall 2 and the construction joint 3 between the floor plate 12 and the side wall 2 are constructed using the same construction method.

[0058] Step 2-2: Reserve steel bars 21 within the side wall 2 above the construction joint 3.

[0059] Please see attached Figure 2 As a preferred embodiment: in the step 2-2, the lower end of the steel bar 21 is pressed against the upper surface of the construction joint template 11, a primary joint is reserved at the lower end of the steel bar 21 and a steel bar connector 22 is installed to facilitate the subsequent connection with the steel bar 21 of the side wall 2 below the construction joint 3 through the primary joint.

[0060] Furthermore, the end of the steel bar connector 22 is sealed with a protective cap, plastic tape, etc. to prevent concrete slurry from entering the sleeve of the steel bar connector 22 during concrete pouring and affecting the subsequent connection of the steel bars 21.

[0061] Please see attached Figure 3 As another preferred embodiment: in the step 2-2, a through hole (not shown in the figure) is formed on the construction joint template 11, so that the lower end of the steel bar 21 passes through the through hole to the bottom of the construction joint template 11, and a first-level joint is reserved at the lower end of the steel bar 21 and a steel bar connector 22 is installed, so as to facilitate the subsequent connection with the steel bar 21 of the side wall 2 below the construction joint 3 through the first-level joint.

[0062] Step 2-3: Synchronously pour the structural slab and the side wall 2 above the construction joint 3 to form structural concrete.

[0063] Step 2-4: After the structural concrete reaches the design strength requirement, remove the side wall buckle frame 10 and the top plate buckle frame 8.

[0064] Step 2-5: Manually chisel at the reverse joint position of the side wall 2 to form a construction joint 3.

[0065] Please see attached Figure 4 , Step 2-6: Carry out waterproof construction at construction joint 3.

[0066] Preferably, in the steps 2-6, the composite wall of the cover-excavation reverse construction station often adopts the installation method of external protection and internal paving, and a waterproof membrane of polymer material is pre-laid on the inner surface of the enclosure structure 13 outside the side wall 2, and a flexible waterproof layer 14 is arranged between the side wall 2 and the enclosure structure 13, and should be connected to the waterproof layer of the top plate 1 and the bottom plate of the main building structure to form an overall closed external waterproof system.

[0067] Preferably, the flexible waterproof layer 14 can be made of waterproof coiled material in the prior art, and the specifications of the waterproof coiled material can be determined according to the waterproof requirements of the actual construction.

[0068] During waterproofing construction, the waterproofing roll material joints at the construction joint 3 should extend beyond the steel bars 21 of the side wall 2 by at least 20 cm. The joints can also be rolled up and fixed, and attention should be paid to later protection.

[0069] Preferably, in the steps 2-6, the surface of the construction joint 3 should be roughened before pouring the concrete of the side wall 2 below it, and the loose concrete on the surface should be cleaned to expose the hard stones, and a cement-based penetrating crystal 15 should be applied, a water-expanding waterstop strip 16 should be set, and the concrete of the side wall 2 below the construction joint 3 should be poured in time.

[0070] When the water-swellable waterstop strip 16 is provided, it should be ensured to be securely fixed.

[0071] Please see attached Figure 5 , step 2-7: pouring concrete of the side wall 2 below the construction joint 3 through the pouring port 17.

[0072] Before pouring concrete, the pumping equipment should be selected according to the actual situation on site, the pump pipe should be arranged reasonably, and the number of elbows should be reduced. The slump of the pumped concrete at the side wall 2 should be 180~220mm, the spacing between the pouring ports 17 set on the side wall 2 should not be greater than 3m, and the height of the concrete poured at each pouring port 17 should not be greater than 0.5m.

[0073] Preferably, in the steps 2-7, when pouring concrete at the construction joint 3, the top surface of the concrete in the pouring port 17 should be higher than the construction joint 3. Preferably, the top surface of the concrete in the pouring port 17 is more than 200 mm higher than the high end of the construction joint 3, and the pouring port 17 is promptly chiseled out after the top plate buckle frame 8 and the side wall buckle frame 10 are removed.

[0074] The advantage of the method of retaining the buckle frame is that the construction joint 3 chiseling process is not affected by the reserved steel bars 21, the quality treatment effect of the construction joint 3 is better, and the mechanical equipment does not involve the problem of protecting the steel bars 21 during the subsequent earthwork excavation. The steel bars 21 of the side wall 2 below the construction joint 3 can be directly connected to the reserved steel bar connector 22, and the waterproofing of the side wall 2 is prevented from being damaged during earthwork excavation. The earthwork within the range of the top plate buckle frame 8 and the side wall buckle frame 10 can be excavated in advance by open excavation, reducing the amount of earthwork to be excavated.

[0075] The above are only preferred embodiments of the present invention and are not intended to limit the scope of protection of the invention. Therefore, any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for retaining construction joints of the side wall of a cover-excavation reverse construction station, characterized by: The method for retaining a construction joint of the side wall of a cover-excavation reverse construction station is used in the cover-excavation reverse construction of the ground formwork retention method. The method for retaining a construction joint of the side wall of a cover-excavation reverse construction station comprises the following steps: Step 1-1: The structural slab and the side wall (2) are excavated in advance to form a structural outline, the design position of the construction joint (3) is located below the structural slab, and the steel bars (21) in the side wall (2) above the construction joint (3) are reserved to below the design position of the construction joint (3); Step 1-2: backfilling sand (7) at the excavated position of the side wall (2), and backfilling the sand (7) to the construction joint (3); Step 1-3: pouring a concrete leveling layer (4) within the range of the structural slab on the ground formwork (6); Step 1-4: an isolation layer (5) is provided on the concrete leveling layer (4), the isolation layer (5) extending to the backfilled sand (7), so that the isolation layer (5) is located between the concrete leveling layer (4) and the structural slab and between the sand (7) and the side wall (2) above the construction joint (3); Step 1-5: synchronously pouring the structural slab and the side wall (2) above the construction joint (3) to form structural concrete; Step 1-6: After the structural concrete reaches the design strength requirement, excavate the earth below the structural concrete and remove the concrete leveling layer (4); Step 1-7: Manually chisel at the reverse joint position of the side wall (2) to form a construction joint (3); Step 1-8: Perform waterproofing at the construction joint (3); Step 1-9: Pour concrete of the side wall (2) below the construction joint (3) through the pouring port (17).

2. The method for leaving construction joints of the side wall of a cover-and-cut reverse construction station according to claim 1, wherein: In the step 1-1, the steel bars (21) in the side wall (2) are reserved to 500 mm below the designed position of the construction joint (3); In the step 1-1, a first-level joint is reserved at the lower end of the steel bar (21) in the side wall (2) and a steel bar connector (22) is installed; In the step 1-1, the structural plate is a roof plate (1) or a floor plate (12).

3. The method for leaving construction joints of the side wall of a cover-and-cut reverse construction station according to claim 1 is characterized in that: In the above-mentioned step 1-2, cement is added to the surface sand of the sandy soil (7), and an inclined surface is artificially built, wherein the inclined surface is located at the construction joint (3); 2% cement is mixed into the sand, and the inclination angle of the slope is 20°-30°, so that the inclination angle of the construction joint (3) is 20°-30°, and the construction joint (3) is 500 mm away from the bottom of the structural plate.

4. The method for leaving construction joints of the side wall of a cover-and-cut reverse construction station according to claim 1 is characterized by: In the steps 1-3, the concrete strength grade of the concrete leveling layer (4) is not less than C15, and the thickness is not less than 50 mm.

5. The method for leaving construction joints of the side wall of a cover-and-cut reverse construction station according to claim 1 is characterized by: In the steps 1-8, the composite wall of the cover-excavation reverse construction station adopts an installation method of external waterproofing and internal pasting, a waterproofing membrane is pre-laid on the inner surface of the enclosure structure (13) outside the side wall (2), a flexible waterproof layer (14) is arranged between the side wall (2) and the enclosure structure (13), and is connected to the waterproof layer of the top plate (1) and the bottom plate of the main building structure, so as to form an overall closed external waterproof system; The surface of the construction joint (3) is roughened before pouring the concrete of the side wall (2) below it, and the loose concrete on the surface is cleaned to expose the hard stones, and a cement-based penetrating crystal (15) is applied, a water-expanding water stop strip (16) is provided, and the concrete of the side wall (2) below the construction joint (3) is poured in time.

6. The method for leaving construction joints of the side wall of a cover-and-cut reverse construction station according to claim 1 is characterized by: In the above steps 1-9, when pouring concrete at the construction joint (3), the top surface of the concrete in the pouring opening (17) is higher than the top end of the construction joint (3) by more than 200 mm, and the pouring opening (17) is promptly chiseled out after the concrete leveling layer (4) is removed.

7. A method for retaining construction joints in the side wall of a cover-excavation reverse construction station, characterized by: The method for retaining a construction joint of a side wall of a cover-excavation reverse construction station is used in the cover-excavation reverse construction of a plate buckle frame retention method. The method for retaining a construction joint of a side wall of a cover-excavation reverse construction station comprises the following steps: Step 2-1: When excavating the soil in the range of the structural plate and the side wall (2), the design position of the construction joint (3) is located below the structural plate, the working surface is excavated to below the design position of the construction joint (3), and the construction joint template (11) is installed through the side wall buckle frame (10); Step 2-2: Reserving steel bars (21) within the range of the side wall (2) above the construction joint (3); Step 2-3: Simultaneously pouring the structural slab and the side wall (2) above the construction joint (3) to form structural concrete; Step 2-4: After the structural concrete reaches the design strength requirement, the side wall buckle frame (10) and the top plate buckle frame (8) are removed; Step 2-5: Manually chisel at the reverse joint position of the side wall (2) to form a construction joint (3); Step 2-6: Perform waterproofing at the construction joint (3); Step 2-7: Pour concrete of the side wall (2) below the construction joint (3) through the pouring port (17).

8. The method for leaving construction joints of the side wall of a cover-and-cut reverse construction station according to claim 7 is characterized by: In the step 2-1, the side wall buckle frame (10) and the top plate buckle frame (8) are connected to form an integrated low formwork buckle frame system; In the step 2-1, the working surface is excavated to 1 m below the designed position of the construction joint (3); In the step 2-1, the inclination angle of the construction joint template (11) is 20°-30°, so that the inclination angle of the construction joint (3) is 20°-30°, and the construction joint (3) is 500 mm away from the bottom of the structural plate; the construction joint template (11) adopts a multi-layer template; In the step 2-1, the structural plate is a roof plate (1) or a floor plate (12).

9. The method for leaving construction joints of the side wall of a cover-and-cut reverse construction station according to claim 7, characterized in that: In the step 2-2, the lower end of the steel bar (21) is pressed against the upper surface of the construction joint template (11), a primary joint is reserved at the lower end of the steel bar (21) and a steel bar connector (22) is installed to connect the steel bar (21) of the side wall (2) below the construction joint (3) through the primary joint; In the step 2-2, a through hole is formed on the construction joint template (11), so that the lower end of the steel bar (21) passes through the through hole to the bottom of the construction joint template (11), and a first-level joint is reserved at the lower end of the steel bar (21) and a steel bar connector (22) is installed for connecting with the steel bar (21) of the side wall (2) below the construction joint (3) through the first-level joint.

10. The method for leaving construction joints of the side wall of a cover-and-cut top-down station according to claim 7, characterized in that: In the steps 2-6, an external waterproofing and internal pasting installation method is adopted in the composite wall of the cover-excavation reverse construction station, a waterproofing membrane is pre-laid on the inner surface of the enclosure structure (13) outside the side wall (2), a flexible waterproof layer (14) is arranged between the side wall (2) and the enclosure structure (13), and is connected to the waterproof layer of the top plate (1) and the bottom plate of the main building structure, so as to form an overall closed external waterproof system; The surface of the construction joint (3) is roughened before pouring the concrete of the side wall (2) below it, and the loose concrete on the surface is cleaned to expose the hard stones, and a cement-based permeable crystal (15) is applied, a water-expandable water stop strip (16) is provided, and the concrete of the side wall (2) below the construction joint (3) is poured in time; In the above steps 2-7, when pouring concrete at the construction joint (3), the top surface of the concrete in the pouring opening (17) is higher than the top end of the construction joint (3) by more than 200 mm, and the pouring opening (17) is promptly chiseled out after the top plate buckle frame (8) and the side wall buckle frame (10) are removed.

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