Construction method for underground buildings by rotary-spray shaft digging method cooperating with semi-inverse method

Abstract

The invention discloses a construction method for underground building combining a rotary jet grouting open caisson method and a semi-inverse method, which relates to the building construction technical field. An underground structure outer wall is integrally preformed on the ground, and the construction method comprises the following construction steps: firstly, a groove is dug, and a guide wallis constructed; secondly, prestress is applied to a preformed underground structure outer wall: after the concrete strength of the preformed wall reaches 70 percent, the prestress is applied and the preformed underground structure outer wall is locked with a prestressed anchorage device; thirdly, jet grouting open caisson is performed to the whole preformed outer wall; fourthly, when the preformed outer wall is sunk to a set depth, mortar is changed to perform the mortar solidifying at the groove bottom and on the groove wall; fifthly, the underground structure is constructed through the semi-inverse method. The construction method adopts the integral jet grouting open caisson method to perform the underground structure, which not only saves a great amount of construction investment and guarantees the security and the quality, but also accelerates the construction progress and shortens the construction period. The construction method is particularly suitable for the rapid constructionof underground buildings, such as the basement of a large-scale civil architecture, a public underground garage and a subway station.

Description

technical field [0001] The invention belongs to the technical field of building construction, and relates to a design and construction method of an underground building, in particular to an underground building exterior wall which is prefabricated on the ground and prestressed by a post-tensioning method. A construction method for constructing deep and large underground structures in conjunction with the semi-upside-down method. Background technique [0002] For the exterior walls of underground buildings that are prefabricated on the ground as a whole, the current prior art mainly uses the jet caisson method to construct the foundation pit enclosure structure. The specific method is: set the caisson blade foot at the bottom of the reinforced concrete caisson wall prefabricated on the ground, the blade foot is made of steel or reinforced concrete, and the outer side of the bottom corner of the outer wall protrudes outward, wider than the outer wall body . When prefabricati...

AI Technical Summary

Problems solved by technology

[0004] 1. Since the position of the nozzle of the water jet is fixed at the foot of the foot, the water sprayed by it is directional, and the water sprayed by each nozzle can only form a soil hole with a limited diameter in the soil layer, and cannot make the bottom The soil plane underfoot is cut away, so that the wall cannot sink when encountering a slightly harder soil layer

When encountering a sandy soil layer, the stratum itself does not make slurry, and the sprayed water cannot discharge the sand particles out of the ground, causing the sand to settle in the water and also preventing the wall from sinking.

[0005] 2. During the sinking process of the water jet caisson, the sinking speed and deviation correction are controlled only by the pressure of the water jet, which is very prone to horizontal drift of the wellbore and failure of deviation correction, resulting in the scrapping of the well body

[0006] 3. If the mud of the jet caisson is not solidified, especially if the mud outside the wall is not solidified, it will easily cause the well body to have no bearing capacity and cannot bear the vertical load, and the outer wall and the soil cannot be tightly combined, resulting in The wall is extremely unstable; and when digging later, it is easy to cause excessive deformation of the ground outside the wall and affect the safety of the surrounding environment

[0007] 4. When the caisson is excavated to the bottom, it is easy to cause groundwater and soil to flow around in areas with high groundwater levels, and piping and soil uplift will occur at the bottom of the pit, which will have a bad impact on the environment outside the pit and may lead to the inability to continue construction

[0008] 5. The blade foot set at the bottom of the jet caisson is generally between 30° and 60°. Under the action of gravity, the blade angle will generate an outward horizontal component force, which will cause the deformation of the outer wall. If the deformation is too large, it will easily cause the structure of the outer wall destroy

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