A basement floor high-low span area structure construction method

Abstract

A basement bottom plate high-low span area structure construction method for accelerating high-span area construction, comprising the following steps: step 1, retaining wall design; step 2, earthwork slope excavation; step 3, low-span area bottom plate construction; step 4, retaining wall construction; step 5, waterproof construction, profile steel support installation; step 6, earthwork backfilling, low-span area outer wall construction; step 7, high-span area bottom plate construction, low-span area beam plate construction; step 8, high-low span area synchronous construction; the application adds a prefabricated retaining wall and corresponding inclined braces outside the low-span area outer wall, so that the earthwork slope area at the high-low span junction can be backfilled in advance, providing working conditions for high-span area and bottom plate construction, accelerating high-span area construction progress, enabling the high-low span area to be constructed synchronously with the low-span area structure, avoiding various construction problems caused by cross operation, and enabling the retaining wall to be integrated with the low-span area subsequently, increasing structural stability.

Description

Technical Field

[0001] This invention relates to the field of building construction technology, and in particular to a method for accelerating the construction of high-span areas in basement floor slabs with varying heights. Background Technology

[0002] During basement construction, some areas have foundation slabs with varying elevations, meaning the elevations of adjacent foundation slabs are inconsistent, resulting in a height difference. Furthermore, the top elevation of the foundation beneath each of the two foundation slabs is also different, leading to varying excavation depths on each side. According to standard construction procedures, at the junction of the high and low spans, sloping earthwork or piling retaining walls should be used on the higher span side to create a working surface for the lower span area's exterior wall construction. This also helps prevent soil collapse during construction in the lower span area.

[0003] However, the earthwork slope method involves a large amount of excavation, and backfilling can only be carried out on the sloped area after the low-span area has reached the design strength. This is to prevent the structure from cracking, tilting, and other quality problems caused by excessive soil stress. In addition, the large amount of backfill soil can only be transported by tower crane due to site road restrictions, which takes up a lot of tower crane operating time and affects the construction of other areas. While the pile retaining method reduces the amount of earthwork excavation, the cost of piles is relatively high, which is not conducive to cost savings. Moreover, the initial pile driving work for retaining the structure still takes up a certain amount of construction time, and it cannot effectively shorten the overall construction period.

[0004] After creating a working surface for the lower-span area's exterior wall construction by using earthwork slope protection or pile retaining, and after the lower-span area's earthwork excavation is completed and the lower-span area's base slab is constructed and reaches a certain strength, the exterior wall structure and waterproofing construction are carried out sequentially. Only then can the trench in the lower-span area be backfilled, that is, the earthwork on the higher-span side at the junction of the high and low spans is backfilled and leveled, and then the base slab construction work in the higher-span area can begin. Following this conventional construction process, when the base slab construction in the higher-span area begins, the lower-span area is usually already under construction up to the second or third floor. When the construction progress on both sides is inconsistent, it is easy to affect each other's construction, delay the overall construction progress, cause overlapping operations, and create significant safety hazards.

[0005] Based on the above problems, there is an urgent need to develop a method to accelerate the construction of the high-span area structure at the junction of high and low spans of the basement floor slab. This method can enable the construction of the high-span area of ​​the basement to start earlier, avoiding delays in the construction of the high-span area due to waiting for the construction of the low-span area structure and earthwork backfilling. Summary of the Invention

[0006] The present invention aims to overcome the defects in the prior art and provides a method for accelerating the construction of the high-span area structure in the basement floor slab, which can enable the construction of the high-span area structure to start earlier and avoid the delay in the construction of the high-span area structure due to waiting for the construction of the low-span area structure and earthwork backfilling.

[0007] To achieve the above objectives, the technical solution adopted by this invention is: a method for accelerating the construction of high-span areas in basement floor slabs, comprising the following steps:

[0008] Step 1, Retaining Wall Design: Based on the backfill soil parameters on the drawings, design the dimensions, reinforcement, and dimensions and spacing of the steel supports for the retaining wall.

[0009] Step 2, earthwork slope excavation: Excavate the foundation pit earthwork to the bottom elevation of the high span area bottom slab cushion layer, determine the starting point of earthwork slope excavation, and then excavate the bottom elevation of the low span area bottom slab cushion layer. The slope surface is excavated and supported by concrete spraying and anchoring at the same time.

[0010] Step 3, Construction of the base slab in the low span area: The subbase and waterproof layer are constructed in sequence in the low span area;

[0011] Step 4, Retaining Wall Construction: Tie the retaining wall reinforcement at the cantilever of the bottom slab in the low span area, and then set up the formwork and pour the concrete. The height of the retaining wall should reach the bottom of the bottom slab in the high span area.

[0012] Step 5, Waterproofing construction and steel support installation: Lay a layer of external wall waterproofing membrane on the inside of the retaining wall; weld both ends of the steel support to the pre-embedded diagonal braces of the low-span area base plate and the retaining wall respectively;

[0013] Step 6: Earthwork backfilling and construction of the exterior wall of the low-span area: After the steel support is installed, backfill the triangular area outside the retaining wall with soil. At the same time, tie the steel reinforcement of the basement exterior wall in the low-span area, erect the side formwork, and pour the concrete.

[0014] Step 7: Construction of the base slab in the high span area and the beams and slabs in the low span area: The formwork for the base slab cushion layer in the high span area and the beams and slabs in the low span area are constructed simultaneously. Then, the reinforcement bars of the base slab in the high span area and the beams and slabs in the low span area are tied together, and concrete is poured at the same time.

[0015] Step 8: Simultaneous construction of high and low span areas: The construction of the superstructure in the subsequent high and low span areas will proceed at the same pace.

[0016] As a preferred embodiment of the present invention, the height of the retaining wall in step 1 is greater than or equal to 200mm, the material of the steel support is 10# or higher steel, and the spacing between adjacent steel supports is 2 to 4m.

[0017] As a preferred embodiment of the present invention, the construction speed of the retaining wall in step 4 is faster than the construction speed of the whole-story structure in the low-span area. The retaining wall can be constructed by on-site assembly of prefabricated components. When the height of the retaining wall is greater than 4 meters, it needs to be poured multiple times.

[0018] As a preferred embodiment of the present invention, the steel supports in step 5 are distributed at equal intervals along the longitudinal direction of the retaining wall.

[0019] As a preferred embodiment of the present invention, the lower interface of the exterior wall waterproof membrane in step 5 is connected to the upper part of the waterproof membrane of the low-span area base plate.

[0020] As a preferred embodiment of the present invention, the waterstop plate mentioned in step 5 should be located in the middle of the low-span basement exterior wall constructed later.

[0021] As a preferred embodiment of the present invention, the steel support in step 5 has a water-stop plate at the end near the retaining wall, and this end should be welded to the pre-embedded diagonal brace on the retaining wall.

[0022] As a preferred embodiment of the present invention, the angle formed between the steel support and the low-span area base plate in step 5 should be greater than or equal to 30°.

[0023] As a preferred embodiment of the present invention, the backfill soil in step 6 is made of low-grade concrete, and the backfill soil provides an operating surface for the construction of the base slab in the high-span area.

[0024] As a preferred embodiment of the present invention, in step 8, after the concrete strength of the basement exterior wall in the low-span area reaches 75%, the exposed part of the steel support is cut and removed.

[0025] The beneficial effects of this invention are:

[0026] 1. This invention adds a precast retaining wall and corresponding diagonal bracing to the outer side of the low-span area, allowing the backfilling of the earthwork slope area at the junction of the high and low spans to be carried out in advance. This provides working conditions for the construction of the high-span area and the base slab, speeds up the construction progress of the high-span area, and enables it to be constructed synchronously with the low-span area's same-layer structure. This avoids various construction problems caused by cross-operations, and the retaining wall can also be integrated with the low-span area in the future, increasing the structural stability.

[0027] 2. This invention eliminates the need to wait for the low-span area to reach its design strength before backfilling the slope location, allowing some steps in the high-span and low-span areas to be constructed simultaneously without affecting the construction of other areas, effectively shortening the overall construction period; at the same time, the cost of retaining walls and diagonal bracing is low, which is beneficial for practical application.

[0028] 3. The retaining wall of the present invention is provided with a waterproof membrane on the side facing the low span area, and the waterproof membrane is connected to the waterproof membrane of the low span area, so as to prevent water from the other side of the retaining wall from entering the low span area through the gap, which is conducive to the comprehensive waterproofing of the low span area and the effective construction; at the same time, a water-stop plate is also provided behind the waterproof membrane to enhance the waterproofing of the low span area.

[0029] 4. The design steps of the retaining wall and steel support of the present invention, which know the size and installation position of the retaining wall, steel support and diagonal brace embedded parts in advance, are conducive to the rational layout of the whole structure and ensure the effective implementation of subsequent steps.

[0030] 5. The exposed portion of the steel support of the present invention can be cut and removed after the concrete strength of the basement exterior wall in the low-span area reaches 75%, which greatly improves the aesthetics and usability of the low-span area. Attached Figure Description

[0031] Figure 1 This is a schematic diagram of the structure of the present invention;

[0032] Figure 2 This is a flowchart of the present invention;

[0033] Figure 3 This is a construction diagram of step 2 of the present invention;

[0034] Figure 4-5 This is a construction diagram of step 3 of the present invention;

[0035] Figure 6 This is a construction diagram of step 4 of the present invention;

[0036] Figure 7 This is a construction diagram of step 5 of the present invention;

[0037] Figure 8 This is a construction diagram of step 6 of the present invention;

[0038] Figure 9-10 This is a construction diagram of step 7 of the present invention;

[0039] Figure 11 This is a construction diagram of step 8 of the present invention;

[0040] The attached diagram is labeled as follows: 1. Retaining wall; 2. Steel support; 3. Waterproof membrane for exterior walls; 4. Sprayed anchor support; 5. Backfill soil; 6. Low-span area base slab; 7. Low-span area base wall; 8. High-span area base slab; 9. Low-span area beam and slab; 21. Diagonal brace embedded part; 22. Waterstop plate. Detailed Implementation

[0041] The embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0042] like Figures 1-10 As shown, a method for accelerating the construction of high-span areas in basement floor slabs includes the following steps:

[0043] Step 1, Retaining Wall Design: Based on the backfill volume, backfill height and other corresponding parameters on the drawings, design the dimensions and reinforcement of retaining wall 1, as well as the dimensions and spacing of steel supports 2.

[0044] Step 2, earthwork slope excavation: After the earthwork of the foundation pit is excavated to the bottom elevation of the 8th cushion layer of the high span area, the starting point of earthwork slope excavation is determined. From this point, earthwork of the low span area is excavated. The slope surface is supported by concrete spraying and anchoring 4 while excavating until it is excavated to the bottom elevation of the 6th cushion layer of the low span area.

[0045] Step 3, Construction of the base slab in the low span area: The foundation layer and waterproof layer are constructed in sequence in the low span area. The base slab 6 in the low span area, together with its foundation, is simultaneously reinforced, poured with concrete and cured. During construction, the base wall 7 of the low span area base slab 6 should be turned up 300mm at the cantilever end.

[0046] Step 4, Retaining Wall Construction: Tie the reinforcing steel of retaining wall 1 at the overhang of the low-span area bottom slab 6, that is, the waterproof membrane under the low-span area bottom slab 6 is turned up to the inside of the retaining wall 1 at the turn-up point of the low-span area basement exterior wall 7. Tie the reinforcing steel of retaining wall 1 above the waterproof membrane, and then carry out formwork and concrete pouring. After the retaining wall 1 reaches the strength of the formwork removal requirements, remove its side formwork. If the retaining wall 1 is a precast component, there is no need for formwork support and removal. The height of the retaining wall 1 should reach the bottom of the high-span area bottom slab 8.

[0047] Step 5, Waterproofing construction and steel support installation: Lay an outer wall waterproof membrane 3 on the inside of the retaining wall 1. The lower interface of the outer wall waterproof membrane 3 is connected to the upper part of the waterproof membrane of the low span area base plate 6. Weld the two ends of the steel support 2 to the diagonal bracing embedded parts 21 of the low span area base plate 6 and the retaining wall 1 respectively. The end of the steel support 2 near the retaining wall 1 has a waterstop plate 22, which should be welded to the diagonal bracing embedded parts 21 on the retaining wall 1.

[0048] Step 6: Earthwork backfilling and construction of the low-span area exterior wall: After the steel support 2 is installed, backfill soil 5 is carried out on the triangular area outside the retaining wall 1. At the same time, the reinforcement of the low-span area basement exterior wall 7 is tied, the side formwork is erected, and concrete is poured.

[0049] Step 7: Construction of the base slab in the high-span area and the beam and slab in the low-span area: After the backfill soil 5 in the high-span and low-span junction area is completed and the concrete strength of the basement exterior wall 7 in the low-span area reaches the required level, the formwork of the base slab 8 in the high-span area and the beam and slab 9 in the low-span area are erected simultaneously. Then, the steel bars of the base slab 8 in the high-span area and the steel bars of the beam and slab 9 in the low-span area are tied together and concrete is poured at the same time. At this time, there is no vertical construction joint left in the junction area.

[0050] Step 8: Simultaneous construction of high and low span areas: The construction of the superstructure in the subsequent high and low span areas will proceed at the same pace.

[0051] This invention completes the construction of a basement with varying spans by sequentially following the steps of retaining wall design, earthwork slope excavation, low-span area foundation slab construction, retaining wall construction, waterproofing and steel support installation, earthwork backfilling and low-span area structural exterior wall construction, high-span area foundation slab construction, low-span area beam and slab construction, and simultaneous construction of high and low span areas.

[0052] Specifically, the waterproofing construction in the low-span area in step 5 can be carried out simultaneously with the installation of steel supports; the backfilling in step 6 can be carried out simultaneously with the construction of the exterior wall of the low-span area; and the construction of the base slab in the high-span area in step 7 can be carried out simultaneously with the construction of the beams and slabs in the low-span area. By simply adding a precast retaining wall and corresponding diagonal bracing, it is not necessary to wait for the low-span area to reach its design strength before backfilling the slope. This allows some steps in the high-span and low-span areas to be constructed simultaneously, effectively shortening the overall construction period. At the same time, the cost of the retaining wall and diagonal bracing is not high, and it will not affect the construction of other areas, avoiding various construction problems caused by cross-operations.

[0053] This invention adds a precast retaining wall and corresponding diagonal bracing to the outer side of the low-span area, allowing for backfilling of the earthwork slope area at the junction of the high and low spans in advance. This provides working conditions for the construction of the high-span area and the base slab, accelerates the construction progress of the high-span area, and enables it to be constructed synchronously with the low-span area's same-layer structure. The retaining wall can also be integrated with the low-span area in the future, increasing structural stability.

[0054] The reinforcement binding and side formwork erection of the basement exterior wall 7 in the low span area described in step 1 can also begin together with the reinforcement binding and formwork erection of the walls and columns in other low span areas, and the concrete pouring can be carried out before the backfill soil 5 is completed.

[0055] The height of the retaining wall 1 mentioned in step 1 is greater than or equal to 200mm. This design dimension is in line with reality, ensuring that the retaining wall 1 has sufficient strength to block the backfill soil 5 and can also effectively separate the low-span area and the high-span area. At the same time, the material of the steel support 2 is 10# or higher steel. The high-strength material further improves the support capacity of the steel support 2 for the retaining wall 1, preventing the backfill soil 5 from squeezing the retaining wall 1 and causing it to deform. The spacing between adjacent steel supports 2 is 2 to 4m. This avoids the cost of deploying too many steel supports 2 with too small a spacing, and also avoids the steel supports 2 not playing an effective supporting role if the spacing is too large.

[0056] The construction speed of retaining wall 1 in step 4 is much faster than that of the whole-story structure in the low-span area. Therefore, conventional construction machinery can be used to backfill one side of retaining wall 1 in a timely manner. When site conditions permit, especially when the lifting capacity of the crane meets the requirements, retaining wall 1 can also be constructed by on-site assembly of prefabricated components, which can further advance the start time of earthwork backfilling. When the height of retaining wall 1 is greater than 4 meters, it needs to be poured multiple times to ensure the strength of the retaining wall itself.

[0057] The steel supports 2 described in step 5 are distributed at equal intervals along the longitudinal direction of the retaining wall 1. The steel supports 2 provide the same support for each section of the retaining wall 1, ensuring that the retaining wall 1 can effectively support the backfill soil 5.

[0058] In step 5, the lower interface of the external wall waterproof membrane 3 is connected to the upper part of the waterproof membrane of the low-span area bottom plate 6, so that the side of the retaining wall 1 facing the low-span area is completely sealed, preventing water from the other side of the retaining wall 1 from entering the low-span area through the gap, which is conducive to the comprehensive waterproofing of the low-span area and the effective construction.

[0059] The waterstop plate 22 mentioned in step 5 should be located in the middle of the low-span basement exterior wall 7 constructed later.

[0060] In step 5, the low-span area base plate 6 is also pre-embedded with a diagonal brace 21 that can be positioned and installed with the steel support 2. The diagonal brace 21 facilitates the positioning and connection between the low-span area base plate 6 and the steel support 2.

[0061] In step 5, the angle between the steel support 2 and the low-span area base plate 6 should be greater than or equal to 30° and less than 70°, which is conducive to the steel support 2 being located in the middle position between the low-span area base plate 6 and the retaining wall 1, so as to play a good supporting role.

[0062] In step 6, the backfill soil 5 is made of low-grade concrete. Low-grade concrete can speed up the backfilling process and improve the overall stability of the backfill area. At the same time, the backfill soil 5 provides an operating surface for the construction of the high-span area base slab 8.

[0063] After the concrete strength of the basement exterior wall 7 in the low-span area reaches 75% as described in step 8, the backfill soil 5 has been completed, the retaining wall 1 has been formed, and the strength of the basement exterior wall 7 in the low-span area is sufficient to support the retaining wall 1. At the same time, the basement exterior wall 7 in the low-span area combined with the retaining wall 1 is also sufficient to support the backfill soil 5. At this time, the supporting effect of the steel support 2 is weakened, and the exposed part of the steel support 2 can be cut and removed to avoid the exposed steel support 2 affecting the use effect of the low-span area and the aesthetics of the low-span area.

[0064] The retaining wall 1 of this invention is located between the low-span area and the high-span area, used for pre-filling and retaining the soil in the high-low span transition area, and also serves as the external formwork for the low-span area of ​​the basement. Correspondingly, when construction conditions permit, the retaining wall 1 can also be a precast retaining wall, further accelerating the construction progress. The steel support 2 is located between the retaining wall 1 and the low-span area, used to support the retaining wall 1 and prevent the backfill soil on one side of the retaining wall 1 from squeezing the retaining wall 1 and causing it to deform. The diagonal brace embedded part 21 is embedded in the retaining wall 1 and the low-span area, used for connecting the steel support 2 with the low-span area base plate 6 and the retaining wall 1. Meanwhile, the location of the steel support 2 was determined to facilitate its rapid installation and positioning with the low-span area base slab 6 and retaining wall 1; the waterstop 22 is located outside the diagonal brace embedded part 21 to prevent water leakage from the steel support 2 located on the exterior wall of the low-span area of ​​the basement; the exterior wall waterproof membrane 3 is used for waterproofing construction of the exterior wall of the low-span area of ​​the basement and the junction of the high and low span areas; the sprayed anchor support 4 is used for slope protection during earthwork excavation at the junction of the high and low span areas to prevent the collapse of the soil in the high span area; the backfill soil 5 is used for backfilling the earthwork (low grade concrete) between the slope and the retaining wall of the high span area to provide an operating surface for the construction of the high span area base slab.

[0065] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention; therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

[0066] Although this paper uses numerous reference numerals from the figures, such as retaining wall 1, steel support 2, exterior waterproof membrane 3, shotcrete and anchor support 4, backfill soil 5, low-span area base slab 6, low-span area basement exterior wall 7, high-span area base slab 8, low-span area beam and slab 9, diagonal brace embedded part 21, and waterstop plate 22, the possibility of using other terms is not excluded. These terms are used merely to more conveniently describe and explain the essence of the invention; interpreting them as any additional limitation would contradict the spirit of the invention.

Claims

1. A method for accelerating the construction of high-span areas in basement floor slabs with varying heights, characterized in that, Includes the following steps: Step 1, Retaining wall design: Based on the parameters of the backfill soil (5) on the drawings, design the dimensions and reinforcement of the retaining wall (1) and the dimensions and spacing of the steel support (2); Step 2, earthwork slope excavation: the earthwork of the foundation pit is excavated to the bottom elevation of the high span area bottom slab (8) cushion layer, the starting point of earthwork slope is determined, and then the bottom elevation of the low span area bottom slab (6) cushion layer is excavated. The slope surface is excavated while being supported by concrete spraying and anchoring (4). Step 3, Construction of the base slab in the low span area: The subbase and waterproof layer are constructed in sequence in the low span area; Step 4, Retaining wall construction: Tie the reinforcing bars of the retaining wall (1) at the cantilever of the bottom slab (6) in the low span area, and carry out formwork and concrete pouring. The height of the retaining wall (1) should reach the bottom of the bottom slab (8) in the high span area. Step 5, Waterproofing construction and steel support installation: Lay a layer of external wall waterproof membrane (3) on the inside of the retaining wall (1); weld the two ends of the steel support (2) to the diagonal bracing embedded parts (21) of the low span area bottom plate (6) and the retaining wall (1) respectively. The end of the steel support (2) near the retaining wall (1) has a water-stop plate (22), which should be welded to the diagonal bracing embedded parts (21) on the retaining wall (1). Step 6, earthwork backfilling and low-span area exterior wall construction: After the steel support (2) is installed, backfill soil (5) is carried out on the triangular area outside the retaining wall (1). At the same time, the reinforcement of the basement exterior wall (7) in the low-span area is tied, the side formwork is erected, and concrete is poured. Step 7: Construction of the base slab in the high span area and the beam and slab in the low span area: The formwork of the base slab (8) in the high span area and the beam and slab (9) in the low span area are constructed simultaneously. Then the steel bars of the base slab (8) in the high span area and the steel bars of the beam and slab (9) in the low span area are tied together and concrete is poured at the same time. Step 8: Simultaneous construction of high and low span areas: The construction of the superstructure in the subsequent high and low span areas will proceed at the same pace.

2. The method for accelerating the construction of high-span areas at the junction of different heights in a basement floor slab according to claim 1, characterized in that, The height of the retaining wall (1) mentioned in step 1 is greater than or equal to 200mm, the material of the steel support (2) is 10# or higher steel, and the spacing between adjacent steel supports (2) is 2 to 4m.

3. The method for accelerating the construction of high-span areas at the junction of different heights in a basement floor slab according to claim 1, characterized in that, The construction speed of the retaining wall (1) in step 4 is faster than that of the whole-story structure in the low-span area. The retaining wall (1) can be constructed by on-site assembly of prefabricated components. When the height of the retaining wall (1) is greater than 4 meters, it needs to be poured multiple times.

4. The method for accelerating the construction of high-span areas at the junction of different heights in a basement floor slab according to claim 1, characterized in that, The steel supports (2) mentioned in step 5 are distributed at equal intervals along the longitudinal direction of the retaining wall (1).

5. The method for accelerating the construction of high-span areas at the junction of different heights in a basement floor slab according to claim 1, characterized in that, In step 5, the lower interface of the exterior wall waterproof membrane (3) is connected to the upper part of the waterproof membrane of the low-span area base plate (6).

6. The method for accelerating the construction of high-span areas at the junction of different heights in a basement floor slab according to claim 1, characterized in that, The waterstop plate (22) mentioned in step 5 is located in the middle of the basement exterior wall (7) of the low-span area constructed later.

7. The method for accelerating the construction of high-span areas at the junction of different heights in a basement floor slab according to claim 1, characterized in that, The angle between the steel support (2) and the low-span area base plate (6) in step 5 should be greater than or equal to 30°.

8. The method for accelerating the construction of high-span areas at the junction of different heights in a basement floor slab according to claim 1, characterized in that, The backfill soil (5) mentioned in step 6 uses low-grade concrete, and the backfill soil (5) provides an operating surface for the construction of the high-span area base slab (8).

9. A method for accelerating the construction of high-span areas at the junction of different heights in a basement floor slab, as described in claim 1, is characterized in that... After the concrete strength of the basement exterior wall (7) in the low span area mentioned in step 8 reaches 75%, the exposed part of the steel support (2) will be cut and removed.

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