A method for determining the lateral additional internal force of side pipelines caused by foundation pit excavation

Abstract

The invention relates to a method for determining the lateral additional internal force of a side pipeline caused by excavation of a foundation pit. The horizontal displacement curve of the enclosure structure caused by the excavation construction; step S3: according to the horizontal displacement curve of the enclosure structure caused by the foundation pit excavation construction determined in step S2, the stress change value of the soil outside the pit under the action of the foundation pit excavation is obtained; step S4: according to the demand The obtained stress change value determines the additional load of the existing pipeline on the side under the action of the foundation pit excavation; step S5: according to the additional load, the additional internal force of the existing pipeline on the side under the action of the foundation pit excavation is determined. The invention can more conveniently determine the lateral additional internal force of the side pipeline under the action of the excavation of the foundation pit, and provides the basis for the support design of the foundation pit of the adjacent pipeline.

Description

technical field [0001] The invention relates to the technical field of construction engineering, in particular to a method for determining the lateral additional internal force of side pipelines caused by foundation pit excavation. Background technique [0002] The rapid development of urban rail transit construction has driven the construction of commercial and real estate projects along its lines and in protected areas. Excavation of foundation pits around existing pipelines is becoming more frequent and closer. Under the influence of the excavation and unloading of the foundation pit, the enclosure structure moves in the direction of the pit under the action of the difference between the water and soil pressure inside and outside the pit, resulting in the change of the earth pressure around the adjacent existing pipeline, which causes the pipeline to generate additional internal force, which seriously threatens the pipeline operational security. [0003] At present, the...

AI Technical Summary

Problems solved by technology

Under the influence of excavation and unloading of the foundation pit, the enclosure structure will move in the direction of the pit under the action of the water and soil pressure difference inside and outside the pit, resulting in changes in the soil pressure around the adjacent existing pipelines, causing additional internal forces on the pipelines, which seriously threatens the pipelines operational security

[0003] At present, there are many analytical studies on the longitudinal impact of foundation pit excavation on existing tunnels, and studies have shown that most of the diseases of subway shield tunnels in soft soil strata are caused by lateral deformation; There are few studies on lateral influence, and they are mainly numerical simulation methods (for example, Zheng Gang et al. used the finite element method to analyze the cross-sectional displacement of tunnels at different locations under different deformation modes and deformation amounts of the envelope structure, and carried out the analysis of the affected area. division); and when calculating the additional stress field of soil outside the pit under the action of foundation pit excavation in the above theoretical analysis studies, most of the unloading effect of foundation pit excavation is simplified to the horizontal load distributed on the side wall to the inside of the foundation pit, and then according to Mindlin stress solution to calculate the surrounding soil stress induced by foundation pit excavation

Images