Advanced construction method for underground ramp

Abstract

The invention discloses an advanced construction method for an underground ramp, and relates to the technical field of underground ramp construction. According to the method, the ramp plate is firstly constructed, namely, formwork erecting and pouring are conducted on the ramp plate while formwork erecting and pouring are conducted on the ramp walls, and the ramp plate bears load through anchor pulling of the ramp walls on the two sides; the reserved manhole is used for disassembling and assembling a template on the lower side of the ramp plate and filling a closed space on the lower side of the ramp, the ramp plate is cured to meet the strength requirement when the closed space is filled, and the problem of cracking of the ramp plate is avoided; and the foamed concrete is directly and fully filled at a time, so that the time of layered tamping is saved, the problem of non-uniform settlement of the foamed concrete is solved, and the construction efficiency and the construction quality are greatly improved.

Description

Technical Field

[0001] The invention relates to the technical field of underground ramp construction, and in particular to an advanced construction method for an underground ramp. Background Art

[0002] Generally, super high-rise buildings, commercial complexes, hospitals, schools and other buildings are designed with two to three basements, and some underground spaces can even be developed to four floors. Some of the ramps are directly from the raft surface to ±0, so that some confined spaces or double-layer ramps are formed at the bottom of the ramp. The construction method generally used for the lower ramp and the closed part is: first, the wall construction on both sides of the ramp is carried out, and the thickness of the ramp is reserved at the ramp elevation as a construction joint, and then the bottom of the ramp is backfilled with soil and compacted in layers to the bottom elevation of the ramp, and finally the ramp structure is constructed. This construction method has some limitations: (1) The enclosed space below the backfill ramp will experience uneven settlement. Even if the backfill is compacted in layers, settlement will still occur. If local settlement of the backfill occurs during the process of the ramp concrete pouring but not solidifying and hardening, the concrete at the settlement location will sink, and cracks will occur during the solidification process. If the lower side of the ramp slab settles uniformly as a whole, cracks will occur at the contact point between the ramp slab and the wall. If the lower side of the ramp slab settles locally, cracks will occur in the structure of the ramp slab at that location. (2) In order to avoid uneven settlement as much as possible, backfilling should be carried out in layers. After backfilling to a certain height, compaction of the new layer is carried out. After compaction is completed, backfilling continues on top of it. This reciprocating operation takes a long time, involves many processes, slows the construction speed, and has a high construction cost. (3) The construction space of double-layer ramps or ramps at corners is limited, making it difficult to interweave the space. Inserting different processes will increase the construction cost dramatically, and there is also a situation where the operation cannot be carried out, which increases the difficulty of protecting the finished product. Summary of the invention

[0003] In order to solve the above technical problems, the present invention provides an advanced construction method for an underground ramp, which first constructs the ramp and then fills it, thereby improving construction efficiency and avoiding settlement and cracking problems.

[0004] To achieve this technical purpose, the present invention adopts the following scheme: The underground ramp advance construction method comprises the following steps: S1. During the reinforcement binding process of the foundation slab, the ramp wall reinforcement is inserted (the top elevation of the inserted reinforcement is up to the top slab of the ramp) and the wall formwork is installed up to the bottom elevation of the ramp; S2. Install the formwork support system on the lower side of the ramp, and reserve a manhole on the ramp for later removal of the formwork support system; S3. Pour the ramp wall and ramp slab concrete, vibrate and compact them, and maintain them until the concrete strength reaches the standard requirements and design requirements; S4. Pour foamed concrete or fluidized soil into the enclosed space below the ramp plate through the manhole until it is filled to the same height as the manhole.

[0005] Compared with the prior art, the beneficial effects of the present invention are as follows: the present invention first constructs the ramp slab, that is, the ramp slab is formworked and cast while the ramp wall is formworked and cast, and the ramp slab relies on the ramp walls on both sides to anchor and bear the load; the reserved manhole is used to disassemble and assemble the formwork on the lower side of the ramp slab and fill the closed space on the lower side of the ramp, and when the closed space is filled, the ramp slab has been solidified to meet the strength requirements, and the ramp slab will not crack; and the foamed concrete is directly filled in one time, which saves the time of layered compaction, and the foamed concrete does not have the problem of uneven settlement, which greatly improves the construction efficiency and construction quality.

[0006] The preferred embodiment of the present invention is: Before pouring the S4 enclosed space, the process also includes: entering the enclosed space below the ramp through a manhole to dismantle the formwork system and transporting it outward through the manhole; and then performing the S4 step.

[0007] The reserved dimensions of the manhole are (0.8~1.2m) × (0.8~1.2m).

[0008] It also includes S5, directly installing the formwork on the ramp surface to directly construct the structural top plate, thereby reducing the support height. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 A side view of the underground ramp advance construction structure provided by the present invention; Figure 2 A top view of the underground ramp advance construction structure provided by the present invention; Figure 3 The continuous ramp construction structure diagram provided by the present invention, wherein the raised part is a plate; Marked in the figure: 1. Foundation slab; 2. Ramp wall; 3. Ramp slab; 4. Enclosed space; 5. Manhole; 6. Structural top plate. DETAILED DESCRIPTION

[0010] In order to fully understand the purpose, features and effects of the present invention, the present invention is described in detail through the following specific implementation methods, but the present invention is not limited thereto.

[0011] like Figure 1 and Figure 2 As shown, the present invention provides an underground ramp advance construction method, the steps are as follows: S1. During the reinforcement tying process of the foundation slab 1, the slope wall reinforcement is inserted according to the requirements of the design drawings, the ramp wall reinforcement is tied below the ramp slab elevation and the wall formwork is installed, and then the foundation slab 1 concrete and ramp wall 2 concrete are poured until the ramp bottom elevation.

[0012] Alternatively, during the steel bar binding process of the foundation slab 1, the slope wall steel bars are inserted according to the design drawing requirements, the ramp wall steel bars are tied at the 300~500mm position (construction joint) on the foundation slab, and the wall formwork is installed within the upper return height, and then the foundation slab concrete and the ramp wall concrete within the upper return height are poured. After the concrete strength of the foundation slab 1 and the ramp wall 2 reaches the design strength, the construction joint joint surface at the top of the ramp wall is processed according to the specification requirements, the ramp wall steel bars from the ramp bottom elevation to the top of the upper return height are tied, and the ramp formwork support system and the ramp wall formwork are installed on the foundation slab 1 until the ramp bottom elevation.

[0013] S2. Process the construction joint surface at the top of the ramp wall in accordance with the specifications, install the formwork support system of the ramp plate 3 at the ramp position, leave reserved holes on the ramp plate 3 template, tie the ramp plate steel bars according to the design drawings, and then form a manhole 5 at the reserved hole position of the ramp plate 3 for later removal of the formwork support system. Preferably, the reserved size of the manhole is (0.8~1.2m)×(0.8~1.2m). It should be noted here that the number of manholes is determined according to the construction disclosure, and can be set from 1 to more. In the actual construction process, a ramp of 10 meters long and 4 meters wide can meet the construction requirements by opening two manholes; if construction efficiency is to be improved, the number of manholes should be increased.

[0014] S3. Continue pouring concrete for ramp wall 2 and ramp slab 3, vibrating and compacting them, and maintaining them until their strength reaches the standard requirements and design requirements.

[0015] S4, construction workers enter the closed space 4 through the manhole 5 to dismantle the formwork system and then transport it out through the manhole 5; Use foamed concrete or other fluid soil to pour directly into the closed space 4 at the lower side of the ramp from the manhole until it is flush with the height of the manhole 5.

[0016] S5. Next, formwork supports are installed on the ramp surface to construct the structural top plate 6 at the top of the ramp. The entire support height is reduced to avoid the occurrence of dangerous projects and reduce safety risks.

[0017] According to the actual construction case effect example, the construction period was saved by about 10 days, and the comprehensive cost (machinery, labor, materials, management, etc.) was reduced by 15%. The key ramp could be used in advance to ensure that the materials could enter the basement through the ramp, and the construction of other basements was carried out simultaneously. From the perspective of the overall arrangement of the entire project, the interweaving of time and space, it has broad construction reference value.

[0018] When there is a continuous ramp or double ramp and the construction space is limited, such as Figure 3 As shown, using the filling method of the prior art, workers are not allowed to enter and exit the black triangle area, the operation is very difficult, and the construction is time-consuming and laborious; after adopting the construction method of the present invention, the black triangle area and other enclosed spaces on the lower side of the ramp are cast with foamed concrete or other fluid soil to avoid the occurrence of basement leakage due to inaccurate vibration. Furthermore, during the construction of the continuous ramp, the upper ramp is cast with foamed concrete, which reduces the weight, and reduces the requirements for the strength of the middle layer raft slab, the number of inserted bars, etc., saving the construction costs of other steps. Furthermore, after the continuous double-layer ramp is successfully built in advance, dual operations of underground construction and ground construction can be carried out simultaneously, which improves the overall construction efficiency and brings about broad benefits of improved construction efficiency.

[0019] The present invention first constructs the ramp plate, that is, while the ramp wall is being molded and poured, the ramp plate is molded and poured, and the ramp plate relies on the ramp walls on both sides to anchor and bear the load; the reserved manhole is used to disassemble and assemble the template on the lower side of the ramp plate and fill the closed space on the lower side of the ramp. When the closed space is filled, the ramp plate has been solidified to meet the strength requirements, and there will be no cracking of the ramp plate; and the foamed concrete is directly filled in one time, which simplifies the construction process, saves the time of layered compaction, and the foamed concrete does not have the problem of uneven settlement, which greatly improves the construction efficiency and construction quality; it avoids the traditional practice that the backfill soil on the lower side of the ramp settles due to the increase in weight during the process interval of layered backfilling and compaction as the support of ramp concrete, pouring ramp plate concrete and concrete hardening, which eventually leads to the quality problem of cracks in the local part of the ramp plate or the contact part with the wall. In general, the construction method of the present invention avoids the time and space interlaced compaction of the backfill soil on the lower side of the ramp, prolongs the construction period of the entire structure and the influence of cross-operation, and realizes the synchronous construction of the entire structure.

[0020] The underground ramp advance construction method of the present invention has the following advantages: (1) reducing the number of working procedures and not requiring other construction insertions, fast construction speed, and easy quality control; (2) reducing quality problems caused by backfill settlement and shortening the construction period; (3) reducing space insertions, reducing construction costs, and easy control of finished product protection; (4) having good implementation effects, improving the overall construction speed, and using the ramp in advance, which is safe; (5) reducing the formwork height of the ramp top plate, reducing safety risks, and reducing safety hazards.

[0021] Finally, it should be noted that the above are only preferred embodiments of the present invention. Of course, those skilled in the art can make changes and modifications to the present invention. If these modifications and variations fall within the scope of the claims of the present invention and their equivalent technologies, they should be considered to be within the scope of protection of the present invention.

Claims

1. A method for advanced construction of underground ramps, characterized in that: The steps include: S1. During the reinforcement tying process of the foundation slab, the ramp wall reinforcement is inserted and the wall formwork is installed until the ramp bottom elevation; S2. Install the formwork support system on the lower side of the ramp, and reserve a manhole on the ramp for later removal of the formwork support system; S3. Pour the ramp wall and ramp slab concrete, vibrate and compact them, and maintain them until the concrete strength reaches the standard requirements and design requirements; S4. Pour foamed concrete or fluidized soil into the enclosed space below the ramp plate through the manhole until it is filled to the same height as the manhole.

2. The underground ramp advance construction method according to claim 1, characterized in that: Before pouring the S4 enclosed space, the process also includes: entering the enclosed space below the ramp through a manhole to dismantle the formwork system and transporting it outward through the manhole; and then performing the S4 step.

3. The underground ramp advance construction method according to claim 1, characterized in that: The reserved dimensions of the manhole are (0.8~1.2m) × (0.8~1.2m).

4. The underground ramp advance construction method according to claim 1, characterized in that: It also includes S5, directly installing the formwork on the ramp surface to directly construct the structural top plate, thereby reducing the support height.

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