Reversed construction method for suspension-type containment deep, large and long foundation pit fabricated structure

Abstract

The invention relates to the field of building underground engineering, in particular to a reversed construction method for a suspension-type containment deep, large and long foundation pit fabricated structure. The method includes the several steps of (1) design calculation, (2) foundation pit engineering construction, (3) underwater control, (4) foundation pit bracing construction, (5) establishment of a basement reinforcement impermeable layer, (6) reversed construction and (7) floor slab structural construction. According to the reversed construction method for the suspension-type containment deep, large and long foundation pit fabricated structure, construction quality of a foundation pit can be controlled easily, the waterproof effect of a basement is good and can be monitored easily, and quality control, overhaul and maintenance are made easy.

Description

technical field [0001] The invention relates to the field of building underground engineering, in particular to an upside-down construction method for an assembled structure of a suspended enclosure protecting a deep, large and long foundation pit. Background technique [0002] At present, similar to the geological characteristics of the binary structure of Wuhan's Class I terraces, the upper part is a fine-grained sedimentary layer of floodplain facies, the lower part is a coarse-grained sedimentary layer of riverbed facies, and the bottom layer is a geological structure of rock strata. The traditional basement construction needs to enclose the foundation pit The design depth of the wall goes up to the rock layer, resulting in a huge expenditure of cost. For the construction of the underground enclosure structure of the alluvial soft soil layer along the river, river and sea, and the geological structure with a high groundwater level, in order to achieve the effect of water...

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Problems solved by technology

[0003] However, this construction method has the following disadvantages: 1. The depth of the diaphragm wall is large, and the construction cost is high. On the basis of meeting the anti-uplift and stability requirements of the pit bottom, the underground diaphragm wall generally needs to exceed the depth by more than 2 to 4 times; 2. The cast-in-place wall is deep. Due to the difficulty in verticality control, the pouring quality is difficult to guarantee when the depth of the groove is large, so it is easy to form weak parts at the joints of adjacent underground diaphragm walls; causing hidden dangers of water leakage and causing the surrounding ground to collapse and threaten the stability of the foundation pit

3. As the scale of underground engineering increases, the construction of the foundation pit takes a long time, which is not conducive to the environmental protection around the foundation pit due to the influence of "time and space effect"

4. The ratio of the reinforcement area in the passive area to the foundation pit area is extremely low, and the contribution of soil reinforcement in the passive area to the stability of the foundation pit cannot be fully utilized

5. The water pressure on the side wall of the fully enclosed water-stop curtain on the side wall of the low-level foundation pit near the river is high. Due to the influence of the geological conditions of the dual structure of the terrace, it is easy to cause side wall leakage or piping to cause excessive settlement of the surrounding area, and in severe cases, it will cause collapse and endanger the foundation. pit stability

6. The excavation efficiency of the traditional upside-down method is low, which greatly affects the construction efficiency of the foundation pit; while the removal and replacement of the temporary horizontal support and the formwork consumption required for the construction of the basement floor slab in the down-to-earth method have caused huge human and material resources to the project. expenditure

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