深基坑加深技术在某工程中的应用

Application of Deep Foundation Excavation Deepening Technology in Some Engineering

某工程在原有旧基坑位置设计新基坑,市政道路的人行道下埋设有多种地下电缆及水管等,对变形要求严格,选择钻孔桩基坑支护。旧基坑上部放坡段经3年观测位移、沉降已趋于稳定,新基坑支护保留上部,支护钻孔桩从-3.5m开始设置。新、旧基坑间回填土作固结处理。结合该工程介绍了基坑支护选择方式,新基坑支护设计方法,以及施工要点,包括钻孔桩施工、袖阀管注浆施工要点。

New foundation excavation is designed based on old foundation excavation for some engineering, underground cables and water pipes are buried under sidewalk, which requires strict for deformation, bored pile is selected to support foundation excavation. The displacement and settlement for step-slope segment tends to be stable by observation with 3 years on the top of old foundation excavation, new foundation excavation support hold upper part,bored piles for support set from -3.5m. Backfill is consolidated between new and old foundation excavation. Based on the engineering, the author introduces selection modes and design method of new foundation excavation support, and construction points, including construction of bored piles, construction points for sleeve valve pipe grouting.