At present, with the development of the city, the depth of the deep foundation pit is getting deeper and deeper, and the scale is getting larger and larger
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In the urban construction, it is easy to have a certain impact on the surrounding buildings, subway, etc., and there are potential safety hazards, which cause the surrounding complaints and rights protection events, and it is difficult to effectively promote the work of the project
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The traditional construction method of multi-storey basement is open excavation
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First, the enclosure is made
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Under the condition of layer by layer support, the excavation is made vertically downward
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After the elevation is set, the reinforced concrete bottom plate is poured
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Then, the basement structure is constructed layer by layer from bottom to top
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After the completion of the underground structure, the construction of the ground structure is carried out, which is a typical sequential construction method
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This method is familiar to all and widely used in cities
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However, the construction method also brings many problems
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The construction period of underground structure is long, accounting for about 1 / 4 ~ 1 / 3 of the total construction period of the whole high-rise building, and the support cost is high
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Secondly, some enclosure structures are only used as temporary structures in the whole basement construction process, which only provide safety guarantee for the basement structure construction
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With the completion of the construction of basement structure, its role will disappear, and the maintenance cost is considerable
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When building in a prosperous commercial city, in order to reduce the impact of commercial activities, traffic, residents’ life and owners’ requirements to shorten the construction period, the reverse construction method is produced
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The reverse construction method is just opposite to the traditional one
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That is, after the completion of maintenance construction and pile foundation construction, the construction shall be carried out first ± 0.00 floor, with excavation opening reserved, excavate the first underground floor, then construct the first underground floor, excavate the second underground floor, and then construct the second underground floor
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Repeat the above process until the basement floor
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During the excavation of underground earthwork, the floor slab with great rigidity is used as the horizontal support of enclosure structure, and many enclosure structures are used as the basement exterior wall
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At the same time of underground earthwork excavation and underground floor construction, the upper structure layer is also constructed layer by layer
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Therefore, compared with the conventional construction method, the reverse construction method can shorten the construction period, save the cost and reduce the impact of the surrounding environment
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It should be widely used in cities in the future
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The following foundation pit engineering support technology and construction process analysis of common problems.
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