A construction method for post-casting settlement strip

Abstract

The present invention discloses a method for constructing a settlement post-cast strip, S1, digging a group of symmetrical wedge-shaped grooves on both sides of a construction area; S2, arranging a plurality of prefabricated cover plates in a transverse manner and placing them in the wedge-shaped grooves, connecting the through-openings of the prefabricated cover plates end to end to complete the placement of the prefabricated cover plates, and vertically placing support rods under the prefabricated cover plates; S3, applying water-stop glue on the bottom of the long side of the prefabricated cover plates, and caulking with an asphalt layer on the outer side of the long side of the prefabricated cover plates and at the joints where the prefabricated cover plates are connected end to end to complete the waterproofing of the prefabricated cover plates; the vents are used as exhaust holes; the exhaust holes can be used for multiple purposes and are also used to detect the casting status of the upper casting layer. Through the prefabricated cover plates, not only can horizontal interlaced construction be effectively realized, but backfill soil can be backfilled in advance, and the post-cast strips are cast in high temperature weather, which can not only shorten the hardening time but also reduce the occurrence of cracks in the post-cast strips during the hardening process.

Description

Technical Field

[0001] The invention discloses a construction method for a post-settlement pouring strip, and belongs to the technical field of building construction. Background Art

[0002] A post-cast strip is a concrete strip left at the corresponding positions of the foundation slab, wall, and beam in accordance with design or construction specifications during construction to prevent harmful cracks that may be caused by uneven shrinkage or settlement of reinforced concrete structures.

[0003] Post-cast joints temporarily divide a structure into sections. After a period of time, after the internal contraction of the components, concrete is poured into these joints to connect the structure as a whole. Post-cast joints should be poured when temperatures are low. Cement or concrete with a trace amount of aluminum powder added to cement should be used. Its strength should be one level higher than the component strength to prevent cracks between the new and old concrete, creating weak spots. However, when construction deadlines are tight, pouring may be necessary even in the warm summer months.

[0004] At present, the post-settlement grouting strip is set up to prevent harmful cracks that may be caused by uneven settlement of the building. The pouring of the post-settlement grouting strip must be carried out after the main construction of the building is completed and the building has completed settlement. After the pouring hardens, backfill soil can be backfilled.

[0005] The existing pouring method basically adopts direct uniform concrete pouring, and since the depth of the post-casting strip is basically more than 1m, it takes a long time for it to fully harden. When the construction period is tight, the backfill soil needs to be backfilled in advance, but the depth of the post-casting strip will be further increased. Therefore, when pouring the settlement post-casting strip, it is easy to cause a hardening time difference between the upper and lower layers due to the deep depth in high temperature weather, resulting in cracks in the post-casting strip during the hardening process.

[0006] Therefore, the purpose of this invention is to effectively realize horizontal interlaced construction in Design 1, and after backfilling the backfill soil, the post-cast strip is cast in high temperature weather, which can shorten the hardening time and reduce the occurrence of cracks in the post-cast strip during the hardening process. Summary of the Invention

[0007] In view of the shortcomings of the existing technology, the purpose of the present invention is to provide a construction method for a settlement post-casting strip, so as to solve the problem that the existing casting method basically adopts direct casting of unified concrete, and since the depth of the post-casting strip is basically above 1m, it takes a long time for it to completely harden. When the construction period is tight, the backfill soil needs to be backfilled in advance, but the depth of the post-casting strip will be further increased. Therefore, when pouring the settlement post-casting strip, it is easy to cause a difference in hardening time between the upper and lower layers due to the deep depth in high temperature weather, resulting in cracks in the post-casting strip during the hardening process.

[0008] In order to achieve the above object, the present invention is implemented through the following technical solutions: a construction method of a settlement post-casting strip,

[0009] S1, dig a set of symmetrical wedge-shaped grooves on both sides of the construction area;

[0010] S2, arranging several prefabricated cover plates horizontally in the wedge-shaped groove, connecting the through openings of the prefabricated cover plates end to end, completing the placement of the prefabricated cover plates, and vertically placing support components under the prefabricated cover plates;

[0011] S3, after applying water stop glue on the bottom of the long side of the prefabricated cover plate, use asphalt layer to caulk the joints on the outside of the long side of the prefabricated cover plate and the joints where the prefabricated cover plates are connected from end to end, to complete the waterproofing of the prefabricated cover plate;

[0012] S4, backfilling the backfill soil around the prefabricated cover plate, and after the backfill is completed, removing the support assembly at the bottom of the prefabricated cover plate;

[0013] S5, pouring concrete into the pouring cavity through the input pipe above the precast cover plate;

[0014] pouring concrete of a first preset slump into the pouring cavity to a first height through an input pipe above the prefabricated cover plate to form a lower pouring layer;

[0015] pouring concrete of a second preset slump into the pouring cavity to a second height through an input pipe above the precast cover plate to form a mixed layer and an upper pouring layer, thereby forming a main waterstop layer;

[0016] S6. After pouring is completed, the adjacent precast cover plates are vibrated at the same time to form a complete post-pouring strip.

[0017] As a further improvement, the first preset slump is X, and the second preset slump range is 135%X-147%X.

[0018] As a further improvement, the casting cavity height Y, the first height is 2Y / 3, and the second height is 1Y / 3.

[0019] As a further improvement, the height ratio among the upper pouring layer, the mixed layer and the lower pouring layer is 2:3:4.

[0020] As a further improvement, before step S2, the prefabricated cover plate needs to be cast, and the specific steps are as follows:

[0021] Mould construction: Build a wooden mould with a set of support plates symmetrically arranged on the bottom edge;

[0022] Rebar construction: Build the reinforcement inside the wooden formwork and extend it to the support plate;

[0023] Pre-embedding: pre-embed an input pipe above the wooden formwork, and pre-embed two sets of ventilation pipes on the side close to the support plate;

[0024] Pouring: Pour the concrete into the wooden formwork, and pull out the vent pipe when it is semi-solidified to form a reserved through hole;

[0025] Forming: The wooden formwork is removed to form a prefabricated cover with an input pipe on top.

[0026] As a further improvement, in step S4, after the support assembly is provided below the prefabricated cover plate, and before the backfill soil around the prefabricated cover plate is backfilled, the method further includes:

[0027] Insert the two ends of the connector into the adjacent reserved holes on the adjacent prefabricated cover plates, and then backfill with soil.

[0028] As a further improvement, before step S2, an expansion strip is placed inside the groove.

[0029] As a further improvement, in step S3, while removing the support assembly, the method further includes:

[0030] Remove the connecting parts, clear the reserved through hole, and insert the casting height measuring rod into a reserved through hole on the prefabricated cover plate.

[0031] As a further improvement, in the step of pouring, it also includes:

[0032] An equal amount of cement was replaced in the concrete, and slag powder was added with 1 / 20 of the cement content.

[0033] As a further improvement, in the step of pouring, it also includes:

[0034] In the concrete, an equal amount of cement was replaced by adding crushed polystyrene foam plastic at 1 / 10 of the cement content.

[0035] The beneficial effects of the present invention are:

[0036] The present invention forms a lower casting layer by pouring concrete of a first preset slump in a casting cavity, and then pouring concrete of a second preset slump on the lower casting layer in the casting cavity. During the casting process, due to the internal height difference, the concrete of the second preset slump falls on the middle area of the lower casting layer, and can be fused with the upper part of the lower casting layer in the form of impact, and spread from the middle to both sides to form a middle mixed layer. When the mixed layer is formed, the concrete in the mixed layer contacts the expansion strip, and the expansion strip absorbs water to expand, thereby further sealing the gap thereof. After the nearby concrete absorbs a certain amount of water, the curing time of the concrete located at the gap is accelerated and can be completed before the internal concrete, thereby further improving the waterproof effect; and with the pouring of the concrete of the second preset slump, an upper casting layer is formed.

[0037] In order to ensure that the slump loss of the upper cast layer 33 remains stable in hot weather to prevent cracking, the present invention sets the first preset slump to X and the second preset slump range to 135% X - 147% X. Since the lower cast layer 31 is covered by the upper cast layer 33 after pouring, its slump loss is lower than that of the upper cast layer 33 even in hot weather. If the second preset slump range is greater than 147%X, the water content of the concrete is relatively high. Since a prefabricated cover plate 1 is provided above the upper casting layer 33, when the water content in the concrete is relatively high, not only will the lower casting layer 31 be excessively diluted, but the setting time will also be prolonged. When the second preset slump range is less than 135%X, even if a prefabricated cover plate 1 is provided above the upper casting layer 33, the slump of the upper casting layer 33 will still be lost in hot weather. Therefore, it is easy for the slump loss to be excessive and cracks will appear. Therefore, the second preset slump range is selected as 135%X-147%X. The slump ratio of the upper pouring layer and the lower pouring layer is set so that the slump of the lower pouring layer is slightly higher than that of the lower pouring layer. In the pouring process, a middle mixed layer can be naturally formed. Therefore, in hot weather, it can not only resist the slump loss of the upper pouring layer, but also reduce the slump loss rate under the cover of the prefabricated cover, thereby avoiding the occurrence of cracks.

[0038] To ensure that the slump loss of the upper pouring layer 33 is stable and that it hardens as synchronously as possible with the lower pouring layer 31, the present invention sets the pouring heights of the upper pouring layer 33 and the lower pouring layer 31. When the first height of the lower pouring layer 31 is greater than 2Y / 3, the concrete pouring amount of the upper pouring layer 33 is severely squeezed. Once the second height of the upper pouring layer 33 is less than 1Y / 3, the slump loss rate of the upper pouring layer 33 is accelerated, causing cracks to appear on the upper side. When the first height of the lower pouring layer 31 is less than 2Y / 3, the concrete pouring amount of the upper pouring layer 33 is increased, causing the second height of the upper pouring layer 33 to exceed 1Y / 3. An overly thick upper pouring layer 33 will result in excessive moisture, affecting the hardening rate of the lower pouring layer 31. Therefore, the first height of the lower pouring layer 31 is set to 2Y / 3, and the second height of the upper pouring layer 33 is set to 1Y / 3. Therefore, the pouring heights of the upper and lower pouring layers are set so that the height of the lower pouring layer is greater than that of the mixed layer and the upper pouring layer. By filling the lower pouring layer with a lower slump, on the one hand, a mixing foundation can be provided for the mixed layer, and on the other hand, its hardening speed can be synchronized as much as possible with that of the upper pouring layer.

[0039] Since the present invention starts pouring from the middle during the pouring process, the height difference in the middle of the mixed layer is still large when it is formed, resulting in a deeper mixing depth in the middle that gradually decreases towards the sides. The ratio is not an absolute ratio, and actual pouring will produce certain fluctuations. However, by pouring according to the corresponding slumps of the lower pouring layer 31 and the upper pouring layer 33, a height ratio close to this can be formed. The height difference between the different pouring layers formed under this slump ratio can make the hardening time of the different pouring layers close to synchronization through the differentiation of slumps during the hardening process of the entire post-casting strip, and the slump configuration of the upper pouring layer 33 makes it the pouring layer with the highest water content in the entire post-casting strip. The slump loss can be reduced by cooperating with the covering of the prefabricated cover plate 1, so that the slump loss curve of the upper pouring layer 33 can be close to flat during the hardening process, thereby reducing the occurrence of more than 98% of conventional cracks.

[0040] Therefore, the prefabricated cover plate not only realizes the effective horizontal interlaced construction, but also allows the backfill soil to be backfilled in advance. Moreover, the post-cast strip is poured in high temperature weather, which can not only shorten the hardening time but also reduce the occurrence of cracks in the post-cast strip during the hardening process. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments. It should be understood that the following drawings only illustrate certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without paying any creative work.

[0042] Figure 1 It is a step diagram of a settlement post-casting strip construction method of the present invention.

[0043] Figure 2 It is a schematic diagram of a three-dimensional structure after the settlement post-casting strip is cast.

[0044] Figure 3 yes Figure 2 Schematic diagram of the enlarged structure at point A in the middle.

[0045] Figure 4 It is a schematic diagram of an uncasted post-settlement grouting strip of the present invention.

[0046] Figure 5 It is a schematic diagram of the completion of backfill construction of a post-settlement pouring zone according to the present invention.

[0047] Figure 6 It is a schematic diagram of the three-dimensional structure of a support assembly of the present invention. DETAILED DESCRIPTION

[0048] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention. Therefore, the following detailed description of the embodiments of the present invention provided in the drawings is not intended to limit the scope of the invention for which protection is sought, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0049] In the description of the present invention, the terms "first" and "second" are used for descriptive purposes only and should not be understood to indicate or imply relative importance or implicitly specify the number of the technical features indicated. Therefore, a feature specified as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, "plurality" means two or more, unless otherwise specifically defined.

[0050] In the description of the present invention, it should be noted that, unless otherwise expressly specified or limited, the terms "connected" and "connection" should be understood in a broad sense. For example, they can refer to fixed connection, detachable connection, or integral connection; mechanical connection, electrical connection; direct connection, or indirect connection through an intermediary. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on the specific circumstances.

[0051] The existing settlement post-casting strip is set to prevent harmful cracks that may be caused by uneven settlement of the building. The settlement post-casting strip needs to be closed after the main structure construction is completed, which takes a long time. Especially in the case of a tight construction period, it is not convenient to pour the post-casting strip because the main structure construction is not completed, but backfill 9 construction can be carried out. Therefore, the construction period can be further shortened by horizontal interlacing construction, and the backfill 9 construction needs to be carried out in advance. However, the forward construction of the backfill 9 will affect the subsequent construction of the post-casting strip. Therefore, the construction of the settlement post-casting strip restricts the forward construction of the backfill 9, causing a contradiction, making it difficult to implement horizontal interlacing construction. Even if the impact of backfill on the post-casting strip construction is reduced as much as possible, in hot weather, it is easy to make the hardening time difference between the upper and lower layers of the post-casting strip, resulting in cracks in the post-casting strip during the hardening process. Therefore, in order to solve the above technical problems, the present invention discloses the following technical solutions:

[0052] Reference Figure 1-6 As shown, a method for constructing a post-casting settlement strip comprises the following steps:

[0053] S1: Dig a set of symmetrical wedge-shaped grooves 4 on both sides of the construction area. The wedge-shaped grooves 4 are stepped, with the deepest part in the middle and decreasing in depth towards the sides. This creates a groove for the waterstop 5 in the deep middle groove, an edge-sealing notch for the asphalt layer 6 on the outside, and an inner sealing strip on the inside that is in full contact with the concrete.

[0054] S2, arrange several prefabricated cover plates 1 horizontally in the wedge-shaped groove 4, connect the through-openings of the prefabricated cover plates 1 end to end to complete the placement of the prefabricated cover plates 1, and place the support assembly 1a vertically under the prefabricated cover plates 1; wherein, the support assembly 1a only acts during the backfilling of the soil 9. In this embodiment, one support assembly 1a requires at least three support assembly 1a rods to support the middle part of the prefabricated cover plate 1.

[0055] S3, after applying water-stop glue 5 on the bottom of the long side of the prefabricated cover plate 1, use an asphalt layer 6 to caulking the outer side of the long side of the prefabricated cover plate 1 and the joints where the prefabricated cover plate 1 is connected from head to tail, so as to complete the waterproofing of the prefabricated cover plate 1; wherein, the water-stop glue 5 needs to be coated on the bottom edge and outer edge of the prefabricated cover plate 1.

[0056] S4, backfill the backfill soil 9 around the prefabricated cover plate 1, and after the backfill is completed, remove the support assembly 1a at the bottom of the prefabricated cover plate 1; during the backfill soil 9 construction, the backfill height does not exceed the height of the upper surface of the prefabricated cover plate 1;

[0057] S5, pouring concrete into the pouring cavity 2 through the input pipe 11 above the prefabricated cover plate 1;

[0058] S6, after pouring is completed, the adjacent prefabricated cover plates 1 are vibrated at the same time to form a complete post-casting strip.

[0059] Before step S2 , an expansion strip is placed inside the groove. After the expansion strip is placed, the prefabricated cover plate 1 is placed, wherein the expansion strip is in contact with the inner side surface of the prefabricated cover plate 1 .

[0060] In step S4, after the support assembly 1a is arranged below the prefabricated cover plate 1 and before the backfill soil 9 around the prefabricated cover plate 1 is backfilled, the following steps are further included:

[0061] Insert the two ends of the connector 7 into the adjacent reserved through holes on the adjacent prefabricated cover plates 1, and then backfill the backfill soil 9. The connector 7 constrains the adjacent prefabricated cover plates 1, so that the prefabricated cover plates 1 can be prevented from moving when the backfill soil 9 is backfilled later.

[0062] After the backfilling of the backfill soil 9 is completed in step S4 and before the concrete pouring is performed in step S5, the method further includes:

[0063] Take out and dismantle the connecting pieces 7 between adjacent prefabricated cover plates 1, and clear the reserved through holes to form observation holes. Insert a pouring height measuring rod 10 into any reserved through hole on the prefabricated cover plate 1. During the pouring process, the pouring height can be determined by pulling out the height measuring rod 10.

[0064] In step S5, pouring concrete into the pouring cavity 2 is specifically as follows:

[0065] S51, pouring concrete of a first preset slump into the pouring cavity 2 to a first height through the input pipe 11 above the precast cover plate 1, to form a lower pouring layer 31;

[0066] S52, pouring concrete of a second preset slump into the pouring cavity 2 to a second height through the input pipe 11 above the prefabricated cover plate 1, forming a mixed layer 32 and an upper pouring layer 33, and forming a main water-stop layer 3.

[0067] To ensure a stable slump loss in the upper cast layer 33 during hot weather and prevent cracking, the first preset slump is set to X, and the second preset slump range is 135%X-147%X. Since the lower cast layer 31 is covered by the upper cast layer 33 after pouring, its slump loss is lower than that of the upper cast layer 33, even in hot weather. If the second preset slump range is greater than 147%X, the concrete has a high water content. Because the upper cast layer 33 is also covered by the precast cover 1, high water content in the concrete not only over-dilutes the lower cast layer 31 but also prolongs the setting time. If the second preset slump range is less than 135%X, even with the precast cover 1 above the upper cast layer 33, slump loss in the upper cast layer 33 can still occur in hot weather, making it prone to cracking due to excessive slump loss. Therefore, the second preset slump range is selected as 135%X-147%X.

[0068] For example, the first preset slump of concrete in the lower casting layer 31 is 10, and the second preset slump of concrete in the upper casting layer 33 is 13.5-14.7. The slump error can be maintained between ±0.2. Furthermore, the second preset slump of concrete in the upper casting layer 33 is 15.

[0069] Since the settlement height of the building body is difficult to preset, after the settlement is completed and before pouring, the height of the pouring cavity 2 is measured by the height measuring rod 10;

[0070] Since there is a prefabricated cover plate 1 above the upper pouring layer 33, the prefabricated cover plate 1 has a certain blocking effect on direct sunlight and can reduce some temperatures. In order to make the hardening speed of the upper pouring layer 33 and the lower pouring layer 31 as synchronized as possible, the pouring interval height constraints of the upper pouring layer 33 and the lower pouring layer 31 are set. The height Y of the pouring cavity 2, the first height is 2Y / 3, and the second height is 1Y / 3.

[0071] To ensure that the slump loss of the upper casting layer 33 remains stable in hot weather and that it hardens as synchronously as possible with the lower casting layer 31, the casting heights of the upper casting layer 33 and the lower casting layer 31 are set. If the first height of the lower casting layer 31 is greater than 2Y / 3, the concrete pouring volume of the upper casting layer 33 is severely squeezed. Once the second height of the upper casting layer 33 is less than 1Y / 3, the slump loss rate of the upper casting layer 33 is accelerated, causing cracks to appear on the upper side. If the first height of the lower casting layer 31 is less than 2Y / 3, the concrete pouring volume of the upper casting layer 33 is increased, causing the second height of the upper casting layer 33 to exceed 1Y / 3. An overly thick upper casting layer 33 will result in excessive moisture, affecting the hardening rate of the lower casting layer 31. Therefore, in this embodiment, the first height of the lower casting layer 31 is set to 2Y / 3, and the second height of the upper casting layer 33 is set to 1Y / 3.

[0072] For example, if the total height of the casting chamber 2 is 90 cm, the first height of the lower casting layer 31 is 60 cm, and the second height of the upper casting layer 33 is 30 cm. When the lower casting layer 31, which has not yet mixed with the upper casting layer 33, is cast, its initial height is 60 cm. During the casting of the upper casting layer 33, the portion that first contacts and mixes with the lower casting layer 31 forms the mixed layer 32. After the upper casting layer 33 has finished casting its second height, the height ratio of the upper casting layer 33, the mixed layer 32, and the lower casting layer 31 is 2:3:4.

[0073] It should be emphasized that, since the pouring process starts from the middle, the height difference in the middle of the mixed layer is still large when it is formed, resulting in a deeper mixing depth in the middle and gradually decreasing towards the two sides. The ratio is not an absolute ratio, and the actual pouring will produce certain fluctuations. However, by pouring according to the corresponding slumps of the lower pouring layer 31 and the upper pouring layer 33, a height ratio close to this can be formed. The height difference between the different pouring layers formed under this slump ratio can make the hardening time of the different pouring layers close to synchronization through the difference in slump during the hardening process of the entire post-casting strip, and the slump configuration of the upper pouring layer 33 makes it the pouring layer with the highest water content in the entire post-casting strip. The covering of the prefabricated cover plate 1 can reduce the slump loss, so that the slump loss curve of the upper pouring layer 33 can be close to flat during the hardening process, thereby reducing the occurrence of more than 98% of conventional cracks.

[0074] A lower pouring layer 31 is formed by pouring concrete of a first preset slump in the pouring cavity 2. During the pouring process, the height of the lower pouring layer 31 is detected by a pouring height measuring rod 10. When the lower pouring layer 31 reaches the preset height, the pouring height measuring rod 10 is removed to serve as a vent 8.

[0075] Then, concrete with a second preset slump is poured on the lower casting layer 31 in the casting cavity 2. During the pouring process, due to the internal height difference, the concrete with the second preset slump falls on the middle area of the lower casting layer 31 and can be fused with the upper part of the lower casting layer 31 by impact. It spreads from the middle to both sides to form a middle mixed layer 32. As the concrete with the second preset slump is poured, the upper casting layer 33 is formed.

[0076] Among them, when the mixed layer 32 is formed, the concrete in the mixed layer 32 contacts the expansion strip, which can make the expansion strip absorb water and expand, further sealing the gap. When the nearby concrete absorbs a certain amount of water, the concrete located in the gap will accelerate its curing time and can complete curing before the internal concrete, thereby further improving the waterproof effect.

[0077] When the concrete is squeezed out of the vent hole 8, the pouring work is completed, and the fluidity of the upper pouring layer 33 is better than that of the lower pouring layer 31. When spreading laterally, it can actively fill the missed areas. Therefore, the pouring cavity 2 can be fully filled to form a high-quality pouring belt.

[0078] A method for casting a prefabricated cover plate in a post-settlement cast zone, comprising the following specific steps:

[0079] Mould construction: Build a wooden mould with a set of support plates symmetrically arranged on the bottom edge;

[0080] Rebar construction: Build the reinforcement inside the wooden formwork and extend it to the support plate;

[0081] Pre-embedding: pre-embed an input pipe 11 above the wooden formwork, and pre-embed two sets of ventilation pipes on the side close to the support plate;

[0082] Pouring: Pour the concrete into the wooden formwork, and pull out the vent pipe when it is semi-solidified to form a reserved through hole;

[0083] Forming: The wooden formwork is removed to form a prefabricated cover plate 1 with an input pipe 11 on the top.

[0084] In the step pouring, it also includes:

[0085] Replacing cement in equal amounts in the concrete and adding a small amount of slag powder can improve the overall hardness of the prefabricated cover plate 1. Therefore, in this embodiment, slag powder with a cement content of 1 / 20 is added. In other embodiments, a trace amount of aluminum powder can also be added.

[0086] In the step pouring, it also includes:

[0087] Replacing cement in equal amounts in the concrete and adding a small amount of polystyrene foam can improve the thermal insulation performance of the prefabricated cover plate 1. Therefore, in this embodiment, crushed polystyrene foam with a cement content of 1 / 10 is added. In other embodiments, other thermal insulation materials can also be used instead.

[0088] A settlement post-casting strip comprises: a prefabricated cover plate 1 is provided above the casting trough to form a casting cavity 2; an input pipe 11 is provided above the prefabricated cover plate 1; concrete is introduced into the input pipe 11 to form a lower casting layer 31, a mixed layer 32, and an upper casting layer 33 from bottom to top in the casting cavity 2.

[0089] As mentioned above, the existing settlement post-casting strip requires a long curing time after pouring, and it is more likely to cause a time difference in hardening of the upper and lower layers in high temperature weather, resulting in cracks in the post-casting strip during the hardening process. Therefore, a lower casting layer 31, a mixed layer 32, and an upper casting layer 33 with different slumps are set, and a prefabricated cover plate 1 is set above the upper casting layer 33 for covering. On the one hand, it reduces direct sunlight, can have a certain thermal insulation effect, can slow down the slump loss of the upper casting layer 33, and make the lower casting layer 31, the mixed layer 32, and the upper casting layer 33 tend to harden synchronously. On the other hand, it can reduce the protection of the casting cavity 2, and then before pouring the post-casting strip, backfill soil 9 is constructed. Through the protection of the prefabricated cover plate 1, the backfill soil 9 can be backfilled without affecting the pouring of the subsequent post-casting strip.

[0090] In order to ensure that the prefabricated cover plate 1 can maintain a high degree of neatness after being arranged horizontally and installed, it also includes a group of wedge-shaped grooves 4 symmetrically arranged on both sides of the casting trough. A plug-in portion 12 is provided under the prefabricated cover plate 1. When the prefabricated cover plate 1 is placed, the plug-in portion 12 is inserted into the wedge-shaped groove 4, and the groove spacing of the wedge-shaped groove 4 is fixed, so that the horizontally arranged prefabricated cover plates 1 can be arranged neatly and can accurately cover the casting trough.

[0091] In order to improve the water-stopping effect, the wedge-shaped groove 4 includes stepped grooves arranged on both sides of the plug-in part 12, and the outside of the stepped groove is filled with water-stopping glue 5, and the water-stopping glue 5 is also filled with an asphalt layer 6. Specifically, the stepped groove includes a first groove bar 41 adjacent to the plug-in part 12, and a second groove bar 42 located above the side of the first groove bar 41. In this embodiment, when performing external water-stopping, the water-stopping glue 5 is applied to the bottom and outside of the first groove bar 41 on the outside of the stepped groove, and the asphalt layer 6 is filled on the second groove bar 42 on the outside of the stepped groove, wherein the asphalt layer 6 separates the water-stopping glue 5 from the outside. On the one hand, it can seal the outside, and at the same time, the asphalt layer 6 can also be filled in the gap between adjacent prefabricated cover plates 1.

[0092] In addition, an expansion strip 43 is filled in the first groove strip 41 on the inner side of the stepped groove. In this embodiment, the expansion strip 43 is a dry expansion agent. During the concrete pouring process, when the expansion strip 43 comes into contact with the concrete, the expansion strip 43 absorbs moisture in the contacted concrete and expands. On the one hand, it can squeeze the concrete in this area, and on the other hand, it can separate the concrete from the water-stop glue 5 to avoid direct contact between the wet concrete and the water-stop glue 5. It can also absorb the moisture of the concrete in this area, thereby reducing the slump of the concrete in this area, and allowing the upper pouring layer 33 covered by it to form a mixed layer 32.

[0093] At the same time, in order to further improve the water-stopping effect, the expansion height of the expansion strip 43 is flush with the bottom of the second groove strip 42, so when the concrete enters the second groove strip 42 on the inner side of the step groove, a buckle can be formed. After it hardens, the mixed layer 32 and the upper casting layer 33 can form a buckle cover inside the prefabricated cover plate 1, thereby further improving the water-stopping effect.

[0094] To ensure a stable slump loss in the upper cast layer 33 during hot weather, preventing cracking and ensuring that it hardens as synchronously as possible with the lower cast layer 31, a slump ratio is set between the upper cast layer 33 and the lower cast layer 31. The first preset slump is X, and the second preset slump range is 135%X-147%X. Since the lower cast layer 31 is covered by the upper cast layer 33 after pouring, its slump loss is lower than that of the upper cast layer 33, even in hot weather. If the second preset slump range is greater than 147%X, the water content of the concrete is relatively high. Since a prefabricated cover plate 1 is provided above the upper casting layer 33, when the water content in the concrete is relatively high, not only will the lower casting layer 31 be excessively diluted, but the setting time will also be prolonged. When the second preset slump range is less than 135%X, even if there is a prefabricated cover plate 1 above the upper casting layer 33, the slump of the upper casting layer 33 will still be lost in high temperature weather, so it is easy for the slump loss to cause cracks.

[0095] For example, the first preset slump of concrete in the lower casting layer 31 is 10, and the second preset slump of concrete in the upper casting layer 33 is 13.5-14.7. The slump error can be maintained between ±0.2. Furthermore, the second preset slump of concrete in the upper casting layer 33 is 15.

[0096] Since the settlement height of the building body is difficult to preset, after the settlement is completed and before pouring, the height of the pouring cavity 2 is measured by the height measuring rod 10.

[0097] Since there is a prefabricated cover plate 1 above the upper pouring layer 33, the prefabricated cover plate 1 has a certain blocking effect on direct sunlight and can reduce some temperatures. In order to make the hardening speed of the upper pouring layer 33 and the lower pouring layer 31 as synchronized as possible, the pouring interval height constraints of the upper pouring layer 33 and the lower pouring layer 31 are set. The height Y of the pouring cavity 2, the first height is 2Y / 3, and the second height is 1Y / 3.

[0098] To ensure that the slump loss of the upper cast layer 33 remains stable in hot weather to prevent cracking and to harden as synchronously as possible with the lower cast layer 31, the casting heights of the upper cast layer 33 and the lower cast layer 31 are set. If the first height of the lower cast layer 31 is greater than 2Y / 3, the concrete pouring volume of the upper cast layer 33 is severely squeezed. Once the second height of the upper cast layer 33 is less than 1Y / 3, the slump loss rate of the upper cast layer 33 is accelerated, causing cracks to appear on the upper side. If the first height of the lower cast layer 31 is less than 2Y / 3, the concrete pouring volume of the upper cast layer 33 is increased, causing the second height of the upper cast layer 33 to exceed 1Y / 3. An overly thick upper cast layer 33 will result in excessive moisture, affecting the hardening rate of the lower cast layer 31. Therefore, in this embodiment, the first height of the lower cast layer 31 is set to 2Y / 3, and the second height of the upper cast layer 33 is set to 1Y / 3.

[0099] For example, the total height of the casting cavity 2 is 120 cm, the first height of the lower casting layer 31 is 80 cm, and the second height of the upper casting layer 33 is 40 cm.

[0100] In order to prevent the prefabricated cover plates 1 from moving due to impact during backfill construction, a connecting member 7 is also included. A connecting member 7 is clamped between two adjacent prefabricated cover plates 1. The connecting member 7 is a rod with two hooks, which is used to fit and fix the two prefabricated cover plates 1.

[0101] In order to provide auxiliary support for the interior of the prefabricated cover plate 1, a support component 1a is also included. The support component 1a abuts against the inner upper surface of the prefabricated cover plate 1. After the prefabricated cover plate 1 is installed, when concrete is not poured into the pouring cavity 2, it can protect the prefabricated cover plate 1, effectively increase the weight that the top of the prefabricated cover plate 1 can bear, and avoid collapse of the middle part before pouring.

[0102] In this embodiment, the support assembly 1a includes three support rods 1a1, and the three support rods 1a1 are connected by rubber strips 1a2, and one end of the three rubber strips 1a2 is fixed integrally, and a traction rope 1a3 is fixed in the middle of the fixed part. The traction rope 1a3 is connected to an adjacent support assembly 1a. Therefore, before pouring, the support assemblies 1a under a whole row of prefabricated cover plates 1 can be taken out by pulling the traction rope 1a3 on the edge.

[0103] The foregoing description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention are intended to be within the scope of protection of the present invention.

Claims

1. A method for constructing a post-casting zone, characterized in that: The steps include: S1, dig a set of symmetrical wedge-shaped grooves (4) on both sides of the construction area; The wedge-shaped groove (4) comprises stepped grooves arranged on both sides of the plug-in portion (12) of the prefabricated cover plate (1), wherein the depth is the highest in the middle and the depth decreases in a stepped manner toward both sides, the stepped groove comprising a first groove bar (41) adjacent to the plug-in portion (12), and a second groove bar (42) located above the first groove bar (41), and an expansion bar (43) is filled in the first groove bar (41) on the inner side of the stepped groove; S2, arranging a plurality of prefabricated cover plates (1) in a transverse manner and placing them in the wedge-shaped groove (4), connecting the through openings of the prefabricated cover plates (1) end to end, completing the placement of the prefabricated cover plates (1), and vertically placing a support assembly (1a) below the prefabricated cover plates (1); The support assembly (1a) abuts against the inner upper surface of the prefabricated cover plate (1), and the support assembly (1a) includes three support rods (1a1), and the three support rods (1a1) are connected by rubber strips (1a2), and one end of the three rubber strips (1a2) is fixed integrally, and a traction rope (1a3) is fixed in the middle of the fixed part, and the traction rope (1a3) is connected to an adjacent support assembly (1a). Before pouring, the traction rope (1a3) on the outermost side can be pulled to remove all the support assemblies (1a) under the entire row of prefabricated cover plates (1); S3, after applying water-stop glue (5) to the bottom of the long side of the prefabricated cover plate (1), an asphalt layer (6) is used to caulk the outer side of the long side of the prefabricated cover plate (1) and the joints where the prefabricated cover plate (1) is connected from end to end, thereby completing the waterproofing of the prefabricated cover plate (1); S4, backfilling the backfill soil (9) around the prefabricated cover plate (1), and after the backfill is completed, removing the support assembly (1a) at the bottom of the prefabricated cover plate (1); S5, pouring concrete into the pouring cavity (2) through the input pipe (11) above the prefabricated cover plate (1); Concrete with a first preset slump is poured into the pouring cavity (2) to a first height through an input pipe (11) above the prefabricated cover plate (1) to form a lower pouring layer (31); Concrete with a second preset slump is poured into the pouring cavity (2) at a second height through an input pipe (11) above the prefabricated cover plate (1) to form a mixed layer (32) and an upper pouring layer (33), thereby forming a main water-stop layer (3). The first preset slump is X, and the second preset slump range is 135%X-147%X; S6, after pouring is completed, the adjacent prefabricated cover plates (1) are vibrated simultaneously to form a complete post-casting strip.

2. A method for constructing a post-casting zone according to claim 1, characterized in that: The casting cavity (2) has a height Y, wherein the first height is 2Y / 3 and the second height is 1Y / 3.

3. A method for constructing a post-casting zone according to claim 2, characterized in that: The height ratio among the upper pouring layer (33), the mixed layer (32) and the lower pouring layer (31) is 2:3:

4.

4. A method for constructing a post-casting zone according to claim 1, characterized in that: Before step S2, the prefabricated cover plate (1) needs to be cast, and the specific steps are as follows: Mould construction: Build a wooden mould with a set of support plates symmetrically arranged on the bottom edge; Rebar construction: Build the reinforcement inside the wooden formwork and extend it to the support plate; Pre-embedding: pre-embedding an input pipe (11) above the wooden formwork, and pre-embedding two sets of ventilation pipes on one side close to the support plate; Pouring: Pour concrete into the wooden formwork, and pull out the vent pipe in a semi-solidified state to form a reserved through hole; Forming: The wooden formwork is removed to form a prefabricated cover plate (1) with an input pipe (11) on the top.

5. A settlement post-casting strip construction method according to claim 1, characterized in that: In step S4, after the support assembly (1a) is arranged below the prefabricated cover plate (1), and before the backfill soil (9) around the prefabricated cover plate (1) is backfilled, the following steps are further included: The two ends of the connecting piece (7) are respectively inserted into the adjacent reserved through holes on the adjacent prefabricated cover plates (1), and then backfilling is performed with backfill soil (9).

6. A method for constructing a post-casting zone according to claim 1 or 5, characterized in that: In step S3, while removing the support assembly (1a), the process also includes: The connecting piece (7) is removed, and the reserved through hole is cleared, and a casting height measuring rod (10) is inserted into a reserved through hole on the prefabricated cover plate (1).

7. A method for constructing a post-casting zone according to claim 4, characterized in that: In the step pouring, it also includes: An equal amount of cement was replaced in the concrete, and slag powder was added with 1 / 20 of the cement content.

8. A method for constructing a post-casting zone according to claim 4, characterized in that: In the step pouring, it also includes: In the concrete, an equal amount of cement was replaced by adding crushed polystyrene foam plastic at 1 / 10 of the cement content.

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