关键词: 既有建筑, 超深基坑, 支护结构, 钻孔咬合桩, 止水帷幕

Abstract: In order to avoid the impact of ultra deep foundation pit support on surrounding buildings and reduce the settlement of surrounding buildings after the completion of support construction, a new foundation pit support construction technology is proposed using a proposed project near the entrance and exit of Daminggong West Station on Xi'an Metro Line 2 as an example. Install drilling interlocking piles around the foundation pit to form the foundation pit enclosure structure, and use an equal thickness cement soil mixing wall. Set up a support system at the longitudinal diagonal of the ultra deep foundation pit to further protect the adjacent residential buildings. Based on the interlocking pile, the prestressed anchor cable installation is completed through four steps: drilling, anchor cable installation, grouting, and anchor cable tension, to strengthen the foundation pit support structure. Building a super deep foundation pit water stop curtain based on the double-sided overlap milling construction method to complete the overall construction of foundation pit support. The monitoring results show that five and a half months after the construction of ultra deep foundation pit support, the maximum settlement value of adjacent buildings is only 7.6 mm, which meets the requirements of foundation pit support construction.

Key words: existing buildings, ultra deep foundation pit, support structure, bored interlocking piles, water stop curtain