Construction Method for Permanent-Temporary Combined Support Frame Beam-Ring Frame Slab of Ultra-Deep Foundation Pit

Abstract

The present invention relates to a construction method for a permanent-temporary combined support frame beam-ring frame slab in an ultra-deep foundation pit, including steps: temporary support at the bottom of the frame beam-ring frame slab, binding of the steel bar cage, formwork erection for the frame beam-ring frame slab, installation of built-in non-removable tie rods, erection of a cantilever-hanging combined operation platform, and concrete pouring. The beneficial effects of the present invention are as follows: a rapid steel bar cage binding device is beneficial to improving the binding efficiency of the steel bar cage of the frame beam-ring frame slab; the problems of difficult setting of the camber of the ring frame slab structure are solved by the jack and the cushion block, and the setting accuracy and efficiency of the camber are improved; different methods are adopted for bottom support according to the thickness of the ring frame slab, which is beneficial to improving the construction efficiency of the lower support structure of the frame beam-ring frame slab structure; built-in integral non-removable tie rods are used to connect the side formwork of the frame beam and the diaphragm wall, improving the stability of formwork erection; a cantilever-hanging combined operation platform is provided as an operation platform.

Description

Technical Field

[0001] The invention belongs to the technical field of super-deep foundation pit engineering construction, and particularly relates to a construction method for a permanent-temporary combined supporting frame beam-ring frame slab of a super-deep foundation pit. Background Technique

[0002] In the past 20-odd years, the design concept of foundation pit engineering has undergone a fundamental change. Early designs often focused on meeting the construction requirements of the underground main project. Due to the lack of standardized guidance, engineering design and construction were mainly based on experience or theory. Nowadays, meeting environmental protection requirements in foundation pit engineering has become the basic starting point for design and construction. It has become a common understanding in the industry that foundation pit engineering must attach great importance to environmental protection and adhere to the combination of theory and experience.

[0003] Under the working conditions of super-deep foundation pits, the implementation of the supporting structure will face many problems. At the same time, due to the structural complexity, it is quite difficult to set up the formwork for the frame beam-ring frame slab concrete structure and set the camber.

[0004] In view of this, how to improve the efficiency of setting up the supporting structure under super-deep foundation pits and at the same time solve the problem of setting the camber of the frame beam-ring frame slab concrete structure urgently requires the invention of a simple and effective construction method. Summary of the Invention

[0005] The purpose of the invention is to overcome the deficiencies in the prior art and provide a construction method for a permanent-temporary combined supporting frame beam-ring frame slab of a super-deep foundation pit.

[0006] This construction method for a permanent-temporary combined supporting frame beam-ring frame slab of a super-deep foundation pit includes the following steps:

[0007] Step 1. Temporary support at the bottom of the frame beam-ring frame slab: Different methods are used for bottom support according to the different thicknesses of the ring frame slab; when the thickness of the frame slab is greater than or equal to 900 mm, part of the soil under the frame slab in the foundation pit is excavated, and the original soil is reserved, and the lower support of the frame slab is formed by a height-adjustable angle steel support frame; when the thickness of the frame slab is less than 900 mm, all the soil under the frame beam-ring frame slab in the foundation pit is excavated, and the lower support of the frame slab is formed by a bottom unit-type scaffolding system;

[0008] Step 2. Binding of the steel bar cage: Build a rapid binding device for the steel bar cage, position and bind the bent steel bar components, then remove the formwork crossbars a and b of the falsework, and hoist the steel bar cage to the designated position;

[0009] Step 3. Formwork erection for the frame beam-ring frame slab: Place the formwork erection device for the frame beam-ring frame slab at the bottom plate of the frame slab, and use a jack and a wedging pad to keep the bottom formwork a with camber, and connect and fix the side formwork of the frame beam and the side formwork bottom plate;

[0010] Step 4. Built-in non-dismantling tie rods: Set tie rods between the diaphragm wall and the side formwork of the frame beam;

[0011] Step 5. Erection of the cantilever-suspension combined operation platform and concrete pouring: Erection of the cantilever-suspension combined operation platform on the diaphragm wall; then pour the frame beam-ring frame slab, and vibrate the concrete and perform other auxiliary construction operations through the cantilever-suspension combined operation platform.

[0012] Preferably, in Step 1: The elevation-adjustable angle steel support frame includes a transverse partition, an upper angle steel support frame and a lower angle steel support frame. Connect the upper angle steel support frame and the lower angle steel support frame and adjust to the suspended height below the ring frame slab, lock it with a limit nut, place the transverse partition inside the angle steel support frame, arrange multiple angle steel support frames side by side below the ring frame slab, and put concrete precast blocks into the partition areas of the angle steel support frames.

[0013] Preferably, in Step 1: The specific method for building the bottom unitary scaffolding system is to lay a steel plate bottom plate as the erection platform, lay the unitary grid plates in an array on the steel plate bottom plate, connect the adjacent unitary grid plates through the grid plate connection bolts passing through the grid plate bolt holes, place the scaffolding vertical rods in the scaffolding limit holes, and fix the scaffolding horizontal rods and scaffolding diagonal rods to the scaffolding vertical rods to form a multi-layer scaffolding. Implant the diaphragm wall reinforcement bars into the diaphragm wall, weld one end of the scaffolding through-length tie bars to the diaphragm wall reinforcement bars, and complete the fixation of the scaffolding by binding at the remaining contact parts with the bottom unitary scaffolding system.

[0014] Preferably, in Step 2: The rapid binding device for the steel bar cage includes a formwork cross bar a, a formwork cross bar b, a formwork vertical bar a, a platform bottom plate and a formwork vertical bar b. Fix the formwork cross bar a, the formwork cross bar b and the formwork vertical bar a with bolt a, place each bent steel bar component in position through the steel bar positioning groove and fasten it with wire. After the binding of the steel bar cage section of the frame beam-ring frame slab is completed, loosen bolt a to release the locking of the formwork cross bar a, the formwork cross bar b and the formwork vertical bar a, and remove the formwork cross bar a and the formwork cross bar b from the rapid binding device for the steel bar cage.

[0015] Preferably, step three is specifically as follows: Place the formwork support device for the frame beam - ring frame slab at the bottom plate of the frame slab. Place the side formwork bottom plate on the bottom formwork a, place the jack on the bottom formwork b, with the upper part of the jack against the bottom formwork a. Calculate the lifting amount x between the bottom formwork a and the bottom formwork b required for the camber of the frame slab. Start the jack to form an upward jacking force, driving the bottom formwork a to rise. When the lifting amount reaches x, wedge a spacer block between the bottom formwork a and the bottom formwork b to keep the bottom formwork with camber, and nail - connect the frame beam side formwork and the side formwork bottom plate. Connect the bottom ends of the side formwork brace a, the side formwork brace b, and the side formwork brace c to the bottom formwork a through the brace limiters respectively, and the top ends of the side formwork brace a, the side formwork brace b, and the side formwork brace c against the frame beam side formwork to complete the formwork erection for the frame beam - ring frame slab.

[0016] Preferably, step four is specifically as follows: First, embed the tie - bar rebars in the diaphragm wall. Weld one end of the tie - bar to the tie - bar rebar, and pass the other end through the side formwork tie - bar hole on the frame beam side formwork and fasten it with the tie - bar limiter.

[0017] Preferably, in step five: The erection method of the cantilever - suspended combined operation platform is specifically as follows. First, embed two rows of I - beam embedded bases, upper and lower, in the diaphragm wall. Connect the I - beams to the I - beam embedded bases by welding. Lay the operation platform bottom plate on the lower row of I - beams, and connect the cantilever parts of the upper and lower rows of I - beams with suspenders.

[0018] The super - deep foundation pit permanent - temporary combined support frame beam - ring frame slab is obtained according to any of the above methods.

[0019] The beneficial effects of the present invention are as follows:

[0020] 1) The structure involved in the present invention can solve the problem of the support construction of the frame beam - ring frame slab structure under super - deep foundation pits, and has good technical benefits.

[0021] 2) Adopting the steel bar cage rapid binding device is beneficial to improving the binding efficiency of the steel bar cage of the frame beam - ring frame slab.

[0022] 3) Adopting the formwork support device for the frame beam - ring frame slab and solving the problem of difficult camber setting of the ring frame slab structure through the jack and the spacer block, improving the setting accuracy and efficiency of the camber.

[0023] 4) Different methods are adopted for bottom support according to the different thicknesses of the ring frame slab. When the thickness of the frame slab is greater than or equal to 900 mm, the elevation - adjustable angle steel support frame is adopted to provide temporary support for the formwork support device of the frame beam - ring frame slab, which is beneficial to improving the construction efficiency of the lower support structure of the frame beam - ring frame slab structure. When the thickness of the frame slab is less than 900 mm, the bottom unit - type scaffolding system is adopted to provide temporary support for the formwork support device of the frame beam - ring frame slab. The bottom unit - type scaffolding system is convenient for erection and is beneficial to improving the construction efficiency.

[0024] 6) The side formwork of the frame beam and the diaphragm wall are connected by an internally built-in integral non-dismantling tie rod, which is beneficial to improving the stability of formwork erection and at the same time improving the formwork removal efficiency.

[0025] 7) An overhanging-suspension combined operation platform is adopted to provide a construction platform for workers, solving the problem that the lack of working space for workers during concrete pouring in ultra-deep foundation pits affects the construction quality. Description of the Drawings

[0026] Figure 1 It is a schematic diagram of the construction system of the permanent-temporary combined support frame beam-ring frame slab of the present invention;

[0027] Figure 2 It is a schematic diagram of the structure of the rapid steel bar skeleton binding device;

[0028] Figure 3 It is Figure 2 The enlarged view of area A in

[0029] Figure 4 It is a schematic diagram of the upper crossbar interface of the rapid steel bar skeleton binding device;

[0030] Figure 5 It is the front view of the structure of the rapid steel bar skeleton binding device;

[0031] Figure 6 It is the left view of the structure of the rapid steel bar skeleton binding device;

[0032] Figure 7 It is a schematic diagram of the formwork support device for the frame beam-ring frame slab;

[0033] Figure 8 It is the front view of the formwork support device for the frame beam-ring frame slab;

[0034] Figure 9 It is a schematic diagram of adjusting the camber of the formwork support device for the frame beam-ring frame slab;

[0035] Figure 10 It is a schematic diagram of the structure of the angle steel support bottom frame;

[0036] Figure 11 It is Figure 10 The enlarged view of area B in

[0037] Figure 12 It is a schematic diagram of the angle steel support bottom frame supporting the frame beam-ring frame slab;

[0038] Figure 13 It is a schematic diagram of the structure of the unitized grid plate;

[0039] Figure 14 It is the left view of the unitized grid plate;

[0040] Figure 15 It is a schematic diagram of the splicing of unit lattice plates;

[0041] Figure 16 It is a schematic diagram of the supporting frame beam - ring frame plate of the bottom unit scaffolding system;

[0042] Figure 17 It is a schematic diagram of the built - in integral non - removable tie rod structure;

[0043] Figure 18 It is Figure 17 an enlarged view of area C in

[0044] Figure 19 It is Figure 17 an enlarged view of area D in

[0045] Figure 20 It is a schematic diagram of the cantilever - hanging combined operation platform structure;

[0046] Figure 21 It is a top view of the cantilever - hanging combined operation platform.

[0047] Among them: 1. Bracket cross - bar a, 2. Bracket cross - bar b, 3. Bracket vertical bar a, 4. Platform bottom plate, 5. Platform diagonal brace a, 6. Platform diagonal brace b, 7. Bracket vertical bar b, 8. Platform side plate, 9. Bolt a, 10. Steel bar positioning groove, 11. Bracket cross - bar b bolt hole, 12. Bracket vertical bar connection groove, 13. Bracket cross - bar a bolt hole, 14. Bracket cross - bar a convex block, 15. Bracket vertical bar a bolt hole, 16. Frame beam side formwork, 17. Side formwork tie rod hole, 18. Side formwork diagonal brace a, 19. Side formwork diagonal brace b, 20. Side formwork diagonal brace c, 21. Diagonal brace limiter, 22. Jack, 23. Bottom formwork a, 24. Bottom formwork b, 25. Hinge, 26. Side formwork bottom plate, 27. Pad block, 28. Diaphragm, 29. Angle steel upper support frame, 30. Angle steel lower support frame, 31. Concrete precast block, 32. Limit nut, 33. Limit hole, 34. Unit lattice plate, 35. Lattice plate bolt hole, 36. Lattice plate connection bolt, 37. Steel plate bottom plate, 38. Diaphragm wall, 39. Diaphragm wall steel bar planting, 40. Tie rod, 41. Tie rod steel bar planting, 42. Tie rod limiter, 43. I - beam embedded base, 44. I - beam, 45. Suspender belt, 46. Operation platform bottom plate, 47. Scaffold vertical bar, 48. Scaffold cross - bar, 49. Scaffold diagonal bar, 50. Scaffold limit hole, 51. Scaffold long - length connecting steel bar, 52. Undisturbed soil. Specific implementation manners

[0048] The present invention will be further described below in conjunction with embodiments. The description of the following embodiments is only for helping to understand the present invention. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present invention, several modifications can still be made to the present invention, and these improvements and modifications also fall within the protection scope of the claims of the present invention.

[0049] As an embodiment, as Figures 1 to 21 shown, a construction method for a permanent-temporary combined supporting frame beam-ring frame slab of an ultra-deep foundation pit, which is characterized by including the following steps:

[0050] Step 1. Temporary support at the bottom of the frame beam-ring frame slab. Different methods are used for bottom support according to the different thicknesses of the ring frame slab. When the thickness of the frame slab is greater than 900 mm, the soil under the frame slab in the foundation pit is excavated, and the original soil 52 of the frame beam is retained. The lower support of the frame slab is formed by a height-adjustable angle steel support frame. The height-adjustable angle steel support frame includes a transverse partition 28, an upper angle steel support frame 29, and a lower angle steel support frame 30. The upper angle steel support frame 29 is butt-jointed with the lower angle steel support frame 30 and adjusted to the suspended height under the ring frame slab, and locked by a limit nut 32. The transverse partition 28 is placed inside the angle steel support frame. Multiple angle steel support frames are arranged side by side under the ring frame slab, and concrete precast blocks 31 are placed in the partition areas of the angle steel support frames.

[0051] Temporary support at the bottom of the frame beam-ring frame slab. When the thickness of the frame slab is less than 900 mm, all the soil under the frame beam-ring frame slab in the foundation pit is excavated, and the lower support of the frame slab is formed by a bottom unitary scaffolding system. A steel plate bottom plate 37 is laid as a construction platform, and unitary grid plates 34 are arranged in an array on the steel plate bottom plate 37. Adjacent unitary grid plates 34 are connected by grid plate connecting bolts 36 passing through grid plate bolt holes 35. The scaffolding vertical rods 47 are placed in the scaffolding limit holes 50, and the scaffolding horizontal rods 48 and scaffolding diagonal rods 49 are fixed to the scaffolding vertical rods 47 to form a multi-layer scaffolding. Anchor bars 39 are implanted into the diaphragm wall 38. One end of the long connecting steel bars 51 of the scaffolding is welded to the anchor bars 39 in the diaphragm wall, and the other parts in contact with the bottom unitary scaffolding system are fixed by tying to complete the fixation of the scaffolding.

[0052] Step 2. Binding of the steel bar cage. Using the rapid steel bar cage binding device as the formwork beam - ring formwork slab steel bar cage binding jig, the rapid steel bar cage binding device includes a jig cross bar a1, a jig cross bar b2, a jig vertical bar a3, a platform bottom plate 4, and a jig vertical bar b7. Fix the jig cross bar a1 to the jig cross bar b2 and the jig vertical bar a3 with bolt a9. Position and fasten each bent steel bar member through the steel bar positioning groove 10 with wire. After the binding of the formwork beam - ring formwork slab steel bar cage segment is completed, loosen bolt a9 to unlock the jig cross bar a1, the jig cross bar b2, and the jig vertical bar a3. Remove the jig cross bar a1 and the jig cross bar b2 from the rapid steel bar cage binding device, and use a hoisting device to lift and place the steel bar cage to the designated position in the foundation pit.

[0053] Step 3. Formwork erection for the formwork beam - ring formwork slab. After the binding of the steel bar cage is completed, carry out formwork erection. Place the formwork beam - ring formwork slab formwork erection device at the bottom of the formwork slab. Place the side formwork bottom plate on the bottom formwork a23, place the jack 22 on the bottom formwork b24, with the upper part of the jack against the bottom formwork a23. Calculate the lifting amount x between the bottom formwork a23 and the bottom formwork b24 required for the formwork slab camber. Start the jack 22 to lift it, forming an upward jacking force to drive the bottom formwork a23 to rise. When the lifting amount reaches x, wedge a spacer block 27 between the bottom formwork a23 and the bottom formwork b24 to keep the bottom formwork with camber. Nail and fix the formwork beam side form 16 to the side formwork bottom plate 26. Place the bottom ends of the side formwork brace a18, the side formwork brace b19, and the side formwork brace c20 against the brace stopper 21, and the upper ends against the formwork beam side form 16 to complete the formwork erection for the formwork beam - ring formwork slab.

[0054] Step 4. Embedded integral non - removable tie rods inside the formwork. Embed tie rod anchor bars 41 in the diaphragm wall 38. Weld one end of the tie rod 40 to the tie rod anchor bar 41, and pass the other end through the side formwork tie rod hole 17 on the formwork beam side form 16 and fasten it with a tie rod limiter 42.

[0055] Step 5. Erection of the cantilever - hanging combined operation platform. Embed two rows of upper and lower I - beam embedded bases 43 in the diaphragm wall 38, and fix the I - beam 44 to it by welding. Lay the operation platform bottom plate 46 on the lower row of I - beams 44, and connect the cantilever parts of the upper and lower two rows of I - beams with a sling 45.

[0056] Concrete pouring. Use commercial concrete to pour the formwork beam - ring formwork slab. During construction, workers can stand on the operation platform bottom plate 46 of the cantilever - hanging combined operation platform to vibrate the concrete or perform other auxiliary construction operations, and finally obtain the formwork beam - ring formwork slab for the permanent - temporary combined support of the ultra - deep foundation pit.

Claims

1. A construction method for a permanent-temporary combined support frame beam-ring frame slab in an ultra-deep foundation pit, characterized in that, It includes the following steps: Step 1. Temporary support at the bottom of the frame beam - ring frame slab: Different methods are adopted for bottom support according to the different thicknesses of the ring frame slab; when the thickness of the frame slab is greater than or equal to 900 mm, part of the soil under the frame slab in the foundation pit is excavated, and the original soil (52) is reserved, and the lower support of the frame slab is formed by the elevation-adjustable angle steel support frame; when the thickness of the frame slab is less than 900 mm, all the soil under the frame beam - ring frame slab in the foundation pit is excavated, and the lower support of the frame slab is formed by the bottom unit-type scaffolding system; Step 2. Binding of the steel bar skeleton: Build a device for quickly binding the steel bar skeleton, position and bind the bent steel bar components, then remove the formwork cross bar a (1) and formwork cross bar b (2), and hoist the steel bar skeleton to the designated position; Step 3. Formwork erection of the frame beam - ring frame slab: Place the formwork erection device of the frame beam - ring frame slab at the bottom plate of the frame slab, and keep the bottom formwork a (23) with a camber through the jack (22) and the wedging block (27), and connect and fix the side formwork of the frame beam (16) and the side formwork bottom plate (26); Step 4. Embedded non-removable tie rods: Set tie rods (40) between the diaphragm wall (38) and the side formwork of the frame beam (16); Step 5. Erection of the cantilever - hanging combined operation platform and concrete pouring: Erect the cantilever - hanging combined operation platform on the diaphragm wall (38); then pour the frame beam - ring frame slab, and vibrate the concrete and perform other auxiliary construction operations through the cantilever - hanging combined operation platform.

2. The construction method of the permanent-temporary combined supporting frame beam-ring frame slab for the ultra-deep foundation pit according to claim 1, characterized in that, In Step 1: The elevation-adjustable angle steel support frame includes a diaphragm plate (28), an upper angle steel support frame (29) and a lower angle steel support frame (30). Connect the upper angle steel support frame (29) and the lower angle steel support frame (30) and adjust them to the suspended height under the ring frame slab, lock them with the limit nut (32), place the diaphragm plate (28) inside the angle steel support frame, arrange multiple angle steel support frames side by side under the ring frame slab, and put the precast concrete blocks (31) into the partition areas of the angle steel support frames.

3. The construction method of the permanent-temporary combined support frame beam-ring frame slab for ultra-deep foundation pits according to claim 1, characterized in that In Step 1: The specific method for building the bottom unit-type scaffolding system is to lay the steel plate bottom plate (37) as the erection platform, array-lay the unit-type grid plates (34) on the steel plate bottom plate (37), connect the adjacent unit-type grid plates (34) by passing the grid plate connection bolts (36) through the grid plate bolt holes (35), place the scaffolding vertical rods (47) in the scaffolding limit holes (50), and fix the scaffolding cross bars (48) and scaffolding diagonal bars (49) to the scaffolding vertical rods (47) to form a multi-layer scaffolding. Implant the diaphragm wall reinforcing bars (39) into the diaphragm wall (38), weld one end of the scaffolding through-long connecting steel bars (51) to the diaphragm wall reinforcing bars (39), and complete the fixation of the scaffolding by binding at the other contact parts with the bottom unit-type scaffolding system.

4. The construction method of the permanent-temporary combined supporting frame beam-ring frame slab for ultra-deep foundation pits according to claim 1, characterized in that, In step 2: the steel frame quick binding device comprises a tire frame cross bar a (1), a tire frame cross bar b (2), a tire frame vertical bar a (3), a platform bottom plate (4) and a tire frame vertical bar b (7), the tire frame cross bar a (1) is fixed with the tire frame cross bar b (2) and the tire frame vertical bar a (3) by bolts a (9), each bent steel bar component is positioned and placed through the steel bar positioning groove (10) and fastened with iron wire, after the frame beam-ring frame plate steel frame segment is bound, the bolts a (9) are loosened to release the lock of the tire frame cross bar a (1), the tire frame cross bar b (2) and the tire frame vertical bar a (3), and the tire frame cross bar a (1) and the tire frame cross bar b (2) are removed from the steel frame quick binding device.

5. The construction method of the permanent-temporary combined support frame beam-ring frame slab for super-deep foundation pits according to claim 1, characterized in that, Step three is as follows: placing the frame beam-ring frame plate formwork device on the frame plate bottom plate, placing the side form bottom plate (26) on the bottom form plate a (23), placing the jack (22) on the bottom form plate b (24), with the upper part of the jack against the bottom form plate a (23), calculating the lifting amount x between the bottom form plate a (23) and the bottom form plate b (24) required for the pre-camber of the frame plate, starting the jack (22) to form an upward force, driving the bottom form plate a (23) to rise, and when the lifting amount reaches x, A pad (27) is wedged between the plate a (23) and the bottom plate b (24), and the frame beam side plate (16) is nailed and fixed to the side plate bottom plate (26); the bottom ends of the side plate diagonal brace a (18), the side plate diagonal brace b (19) and the side plate diagonal brace c (20) are connected to the bottom plate a (23) through diagonal brace limiters (21), and the top ends of the side plate diagonal brace a (18), the side plate diagonal brace b (19) and the side plate diagonal brace c (20) are pressed against the frame beam side plate (16), thereby completing the frame beam-ring frame plate plate support.

6. The construction method of the permanent-temporary combined support frame beam-ring frame slab for ultra-deep foundation pits according to claim 1, characterized in that, Step 4 is as follows: first, pre-embed the tie rod reinforcement (41) on the ground-connected wall (38), weld one end of the tie rod (40) to the tie rod reinforcement (41), and pass the other end through the side mold tie rod hole (17) on the frame beam side mold (16) and fasten it with a tie rod limiter (42).

7. The construction method of the permanent-temporary combined support frame beam-ring frame slab for ultra-deep foundation pits according to claim 1, characterized in that In step 5, the method for erecting the cantilever-hanging combined operating platform is specifically as follows: first, two rows of I-beam embedded bases (43) are embedded on the ground-connected wall (38), the I-beams (44) are connected to the embedded bases (43) by welding, the operating platform bottom plate (46) is laid on the lower row of I-beams (44), and the cantilever parts of the upper and lower rows of I-beams are pulled together by slings (45).

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