Predeformation support method for pipeline foundation pit

Abstract

The invention discloses a pipe foundation pit predeformation support method. The method comprises the following steps: (A) a part above a final step is divided into multiple steps; and soil bodies on the step surfaces are removed, so that the active soil pressure on the sliding surfaces of the soil bodies is reduced, and the sliding of the soil bodies on the sliding surfaces is allowed; (B) steel plate piles or cavity piles are arranged on the vertical surfaces of all the steps; the acting force of the previous steps is not transferred to the later steps; the steel plate piles or the cavity piles bear the biggest value of the active soil pressure in the steps or the sliding force in the sliding soil bodies; and the deformation of the steel plate piles or the cavity piles satisfies the material and integrity requirements of a support structure; and (C) measuring points are preset on all the steel plate piles or the cavity piles, and are directly measured; the parts with the deformation exceeding a normal limit state are reinforced; and the generation of unstable state is controlled timely. The method allows the soil bodies on all the steps above the final step to generate large deformation, even the deformation exceeding dozens of centimeters, so that the construction process is simple, the procedures are easily realized, and the construction cost is far lower than that of the foundation pit support design controlled according to small deformation.

Description

Technical field: [0001] The invention relates to a pipeline foundation pit support technology, in particular to a pipeline foundation pit pre-deformation support method. Background technique: [0002] Foundation pit support is a temporary project for the construction of buildings below the ground. Its basic function is to ensure the short-term operation safety of the foundation pit, and the surrounding buildings (or structures) of the foundation pit will not be affected or although they are affected, the surrounding buildings will be affected. It has no effect on the function and use of the foundation pit, that is, the deformation generated after the excavation of the foundation pit is within the range of the anti-deformation value of the existing building. [0003] The difference between oil and natural gas pipeline foundation pit engineering and building foundation pit engineering is that in most cases, it is located in an open area without buildings-fields, rivers, floodp...

AI Technical Summary

Problems solved by technology

The interaction between the support structure and the soil is not considered in the deformation of the foundation pit, and the soil is still calculated according to the setting conditions of the homogeneous body, so there are theoretical defects

The rigidity of the top of the support structure (because of the role of the crown beam structure) is large enough compared to the rigidity of the lower structure. Engineering practice shows that the support structure often undergoes drum and dish deformation. Obviously, a single top deformation control design is adopted. Does not conform to the actual working conditions of the pipeline foundation pit project

[0005] There are still problems in this method: 1. The construction technology is complicated, and the small deformation foundation pit project has relatively high requirements on the construction technology of the support structure, and there are many links. The structure cannot be reused. Although the supporting structure is temporary, it is permanently buried around the building, causing environmental pollution or affecting the construction of adjacent buildings.

Therefore, the construction time of the foundation pit is long, and the time and space for the deformation of the rock and soil mass and the supporting structure are given. The process content is complicated, and it is not suitable for rapid foundation pit engineering.

2. Monitoring is expensive and has many links. The components are buried once and there is no chance of reuse. For example, the earth pressure box and the steel stress gauge are buried in the soil or concrete, and the supporting structure cannot be taken out after the function is completed.

These components are very expensive, are single-use, and do not meet the requirements for reuse

There are many steps to install the components, which require the construction party and the monitoring party to work together and adopt a variety of technological measures. In most cases, the construction party's welding, installation, protection and other technologies and awareness are relatively weak, and often cannot complete the work according to the established requirements.

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