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利用离心模型试验、Biot固结理论的有限元和现场观测数值相结合的方法,对上海地区⑤-2层浅承压水和⑦层深承压水间的⑥层隔水层的存在或缺失对基坑变形和降水影响的研究表明,承压水隔层将对基坑开挖时的变形产生较大的影响。基坑开挖深度14．4～18 m、承压水位降低4 m 以内、承压水隔层厚度为5．8 m时,承压水隔层缺失将导致地表沉降最大值增加10％～20％,连续墙墙脚水平位移、基底最大隆起增加30％左右。基坑开挖较深时,不能用单一的抗突涌安全系数来控制承压水的降低程度;当承压水隔层缺失时,深层承压水降对浅层承压水位、地面沉降有影响,但影响主要发生在后期。
Using the combination of the centrifugal model test, Biot consolidation theory and the on-site observation data, the existence or absence of ⑥ aquifuge between ⑤-2th layer of shallow confined water and ⑦stage of deep confined water in Shanghai The research on the influence of the deformation and precipitation of the foundation pit shows that the confined water layer will have a great influence on the deformation during excavation. When excavation depth of foundation pit is 14.4 ~ 18 m, bearing water level is reduced within 4 m and pressure water barrier thickness is 5.8 m, the loss of confined water layer will increase the maximum value of surface subsidence by 10% ~ 20 %, Horizontal displacement of continuous wall feet, the maximum base uplift about 30%. When deep pit excavation, can not use a single anti-surging safety factor to control the reduction of confined water; when the confined water barrier is missing, the deep confined water pressure on the shallow confined water level, ground subsidence Impact, but the impact occurred mainly in the late.