Construction method for foundation pit excavation

Abstract

The invention relates to the technical field of building construction, in particular to a construction method for foundation pit excavation. The construction method comprises the following steps: construction conditions are determined and a foundation pit model is established; the construction process is simulated and the axial force and deformation control method is utilized for carrying the construction; layered excavation is adopted and the automatic compensation function to the corresponding support axial force of the upper layer is simultaneously closed; the support axial force of the closest layer is adjusted in turn according to the axial force coherence control method; whether the support axial force reaches the support axial force limit value is judged, the current axial force value is taken as the axial force control value of the current layer, and the changed support axial force of the upper layer is taken as the axial force control value of the upper layer; then the excavation is continued and the automatic compensation function to the support axial force of the upper layer is simultaneously closed; and the excavation of the next layer is carried after the excavation ofthe current layer is finished and the process is repeated until the whole foundation pit is finished. By combining the axial force and deformation control method with the axial force coherence control method, the invention can be used for compensating and controlling the deformation of the excavation face and realizing the main control to the lateral soft soil for enclosing.

Description

Technical field [0001] The invention relates to the technical field of building construction, in particular to a foundation pit excavation construction method. Background technique [0002] In order to meet the more stringent environmental protection requirements around the foundation pit, the existing technology is to install an axial force servo system on the steel support to solve the problem of deformation of the foundation pit due to the loss of axial force, and it is widely used. The system can monitor the axial force in real time, and compensate the lost axial force based on the monitoring data, thereby realizing the active control of the axial force, effectively overcoming the shortcomings of incompletely knowable, uncontrollable and inconvenient adjustment of the follow-up axial force changes of traditional steel supports. Because the axial force servo system solves the possible influence of pit deformation caused by the axial force loss, it is widely used. [0003] Howev...

AI Technical Summary

Problems solved by technology

[0003] However, the axial force servo system only solves the problem of axial force loss. The goal of control is to support the axial force. When the corresponding relationship between the axial force and displacement is relatively consistent, the displacement control effect will be better. When the difference between the two is large, Often unsatisfactory even with servo system deformation control

There is still little research on how to use the servo system to control the deformation of the foundation pit. In particular, the maximum lateral deformation of the enclosure in soft soil foundation pits often occurs below the excavation surface, and it continues to develop downward as the excavation proceeds. There is still a lack of direct and effective means for controlling the deformation of the enclosure below the excavation face.

[0004] Moreover, in the deep foundation pit of iron in soft soil, the rheological characteristics of the soil have an important influence on the deformation of the foundation pit, and it is difficult to accurately calculate and control

Images