中文摘要：

为了研究地铁基坑坑底加固对周边土体位移的影响,通过某软土地基地铁基坑南北测试段的水泥搅拌桩加固效果进行静力触探测试获得加固前、后锥尖阻力,计算得到南北测试段加固后土体无侧限抗压强度分别为0.58和1.17 MPa.对南北测试段表面沉降和地连墙水平位移进行实测,得到南北测试段地连墙最大水平位移分别为81.3、48.3mm,地表沉降最大值分别为-79.1、-40.2mm.建立Plaxis有限元计算模型,分析不同坑底加固效果工况下基坑开挖变形情况,模拟结果与实测结果基本一致.分析结果表明,南北测试段坑底加固后地连墙最大水平位移分别降低40%和64%,地表沉降分别降低26%和63%,地基加固能够有效地减小地铁基坑围护结构水平变形和地表沉降.

英文摘要：

The values of soil cone resistance were obtained by cone penetration tests before and after the foundation reinforcement in order to analyze the influence of foundation reinforcement on soil deformation surrounding metro excavation.The unconfined compressive strengths of soil reinforced in the south and north test sections were 0.58 MPa and 1.17 MPa respectively.The lateral wall deflections and the ground settlements were measured.The maximum lateral wall deflections in the south and north test sections were 81.3mm and 48.3mm respectively.The maximum ground settlements were -79.1mm and -40.2mm respectively.The finite element models were established by Plaxis,which parameters used results of field tests.The simulation results accorded with the measured results.The analysis results showed that the maximum lateral wall deflections were reduced by 40% and 64% respectively,after being reinforced in the south and north test sections.The maximum ground settlements were decreased by 26% and 63% respectively.Foundation reinforcement can effectively reduce the lateral wall deflections and the ground settlements of metro excavations.