土工基础

土工基础 ›› 2022, Vol. 36 ›› Issue (6): 997-1001.

• 测试技术 • 上一篇    下一篇

厚粉黏土层中SMW工法桩围护基坑的开挖响应实测研究

刘洪伟   

  1. (中铁二十二局集团轨道工程有限公司，北京 100101)
  • 收稿日期:2022-08-21 修回日期:2022-09-01 出版日期:2022-12-31 发布日期:2022-12-28
  • 作者简介:刘洪伟(1990-)，男，工程师，研究方向为城市轨道交通工程的建设管理。
  • 基金资助:
    中铁二十二局集团有限公司科研计划课题资助（21-14C）

Construction Monitoring of Deep Excavation Response Supported by SMW Method Columns in Thick Silty Clay Soils

LIU Hongwei   

  1. (China Railway 22nd Bureau Group Track Engineering Co. Ltd., Beijing 100101)
  • Received:2022-08-21 Revised:2022-09-01 Online:2022-12-31 Published:2022-12-28

摘要： 目前，地下轨道交通已成为解决城市拥堵、形成城市主脉络的重要基建工程，但其建设过程涉及的基坑开挖往往会诱发地层变形，继而影响周围环境。以苏州地铁白荡南站基坑为例（SMW工法桩围护），选取标准段对内支撑轴力、围护墙顶竖向/水平位移、墙身水平位移、地下水位以及地表沉降进行实时监测数据分析。分析发现：①基坑内支撑轴力在土方开挖过程中整体呈现增大趋势，同时支撑力会逐渐向下部转移；②围护墙顶整体呈现向基坑外侧发生水平位移的趋势，且随基坑开挖愈发显著。同时，伴随基坑内外应力状态在开挖过程中发生变化，坑底土体隆起使得围护墙顶呈现整体抬升趋势；③围护墙身在基坑开挖过程中呈现胀肚型，且围护墙体的最大水平位移位置随着基坑开挖逐渐下移至坑底附近；④多数测点的地表沉降值持续累积，并在基坑开挖完成后逐渐趋于平缓，最大地表沉降约为基坑深度的0.16%，表明SMW工法桩支护方案在厚粉黏土中具有良好的适用性。 

关键词: 基坑, SMW工法桩, 粉黏土, 监测

Abstract: The underground rail transit has become an important infrastructure project type to solve the urban congestion and to form one of the major urban contexts. The deep excavation process often induces soil stratum deformation, which in turn might adversely affect the surrounding environment. This paper presents the case history of the Baidang South Station of Suzhou Metro deep excavation response supported by Soil Mixing Wall (SMW) columns. A typical section was selected to conduct that real-time monitoring data analysis on the axial force of the inner support, the vertical/horizontal displacement of the top of the retaining wall, the horizontal displacement of the retaining wall, the groundwater level and the ground surface subsidence. The results indicate that: 1) The supporting axial force in the supporting structure showed an overall increasing trend during the excavation process, and the supporting force would gradually transfer to the lower portion of the structure; 2) The top of the retaining wall showed a trend of horizontal displacement towards to direction of excavation, and with the deep excavation was becoming more and more pronounced. With the deeper excavation, the stress state inside and outside the excavated area changes, and the soil at the bottom of the excavation heaves, causing the retaining wall to show an overall uplift trend; 3) During the deeper excavation, the retaining wall shows a swelled belly shape, and with the excavation, the position of the maximum horizontal displacement of the retaining wall gradually moved down to the vicinity of the excavated bottom; 4) The surface settlement values of the most measuring points continue to accumulate, and gradually become flat after the completion of the excavation, and the maximum surface settlement is about 0.16% of the depth of the excavation, indicating that the SMW method column has a good applicability in deep excavation supporting in the thick silty clay soils.

Key words: Deep Excavation, SMW Method Column, Silty Clay, Monitoring

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