关键词: 基坑支护, 管线保护, 数值模拟, 变形规律

Abstract: During the foundation pit excavation, how to reduce the disturbance to the existed pipeline is a key problem to be solved urgently under the premise of meeting the supporting requirement of foundation pit. Based on a heat pipeline project, several pipeline models in the deep foundation pit excavation are established to obtain the stress and displacement change regularity of sidewall and pipeline. When the pipeline crosses the foundation pit horizontally, the deformation mode before support was U-shaped, and then it changed to W-shaped under suspension support, and the deformation mode became VVV-shape under simply support, and the stress is 1/10~1/7 times of the original. The horizontal displacement of pit sidewall decreased at first, then increased and finally decreased again with the excavation depth increasing, and the maximum displacement occurred beneath the pipe culvert. Using the steel I-piles + lateral support for side wall and simply support for pipe culvert, the horizontal displacement of the side wall reduced from 125.43 mm to 20.53 mm. The proposed method not only can meet the requirements of on-site construction, but also effectively can control the deformation of existing pipeline.

Key words: foundation pit support, pipeline protection, numerical simulation, deformation law