摘 要
隨著現代城市建設的快速發(fā)展，地下空間的進一步開發(fā)利用，深基坑工程施工對周圍環(huán)境的影響已受到高度重視。如何有效控制基坑開挖過程中圍護結構變形、坑周土體位移，保護周圍建筑及公用設施安全是基坑工程必須考慮的問題。本文以上海市長江西路越江隧道工程浦東工作井深基坑工程為背景，對軟土地區(qū)深基坑的開挖、支護施工全過程中圍護結構及土體變形規(guī)律及控制措施展開研究，主要內容如下：
1、對上海長江西路越江隧道工程浦東工作井28m超深基坑開挖過程中的圍護結構及周邊土體位移進行實測研究，根據該基坑的支護結構設計及施工方案，制定了相應的監(jiān)測方案；對不同工況下地下連續(xù)墻側向位移、墻頂沉降、墻后土體沉降、支撐軸力、格構柱沉降以及基坑周圍建筑物沉降進行全過程監(jiān)測；對監(jiān)測結果進行了深入分析，得到了多支撐基坑在不同工況下，圍護墻體位移隨深度的變化規(guī)律、格構柱沉降和連續(xù)墻墻頂沉降隨時間變化規(guī)律、支撐軸力隨時間變化規(guī)律、墻后土體沉降與水平距離之間的變化規(guī)律等，為同類基坑設計提供參考。
2、對工程圍護方案，按照實際施工工況，進行施工全過程三維有限元模擬，模擬過程中考慮土體非線性、土與結構的共同作用等；借助ADINA有限元軟件，求得不同工況下圍護墻體位移、坑底回彈、支撐軸力、墻后土體的位移等。
3、對上海市長江西路越江隧道新建工程浦東工作井深基坑工程現場實測數據與數值模擬結果進行比較，分析存在差別的原因及數值模擬的不足，為超深基坑設計提出合理建議。



關鍵詞 軟土；超深基坑；監(jiān)測分析；有限元；變形特性


Abstract
With the rapid development of modern urban construction, and further development and utilization of underground space, the deep foundation construction on the surrounding environment influence has been highly valued. How to control the retaining structure deformation and soil displacement around deep foundation, protect the surrounding buildings and public facilities is the question which must be considered in excavation process. Background in Pudong working well of Shanghai West Changjiang Road Tunnel, a series of studies for deformation law and control measures of retaining structure and soil in the whole process of excavation and supporting construction of deep foundation in soft soil area is carried out, the main contents are as follows:
1.At the excavation process of foundation with depth of 28m of Pudong working well of Shanghai West Changjiang Road Tunnel, retaining structure deformation and surrounding displacement of soil are actually measured and researched, and the appropriate monitoring scheme is formulated according to the design and construction project of supporting structure of this foundation. In different conditions, the lateral displacement and the vertical displacement of diaphragm wall, the settlement of lattice column and soil behind the wall, the axial force of struts, and the settlement of existing buildings are made on monitoring in the whole process. A profoundly analysis is made to monitoring results, then obtained the laws of the displacement of diaphragm wall varied with depth, the settlement of lattice column and the vertical displacement of diaphragm wall varied with time, the axial force of struts varied with time, and the settlement of soil behind the wall varied with horizontal distance, can provide a reference to design of same foundation.
2.The full construction process of the retaining scheme in this project was simulated by three-dimensional finite element software-ADINA according to the actual construction conditions, the nonlinear of soil and interaction between soil and structure are considered in simulation process. The displacement of diaphragm wall, soil resilience, the axial force of struts, the displacement of soil behind the wall, and so on are obtained in different conditions.
3.The actual measurement data and numerical simulation results are compared in the project of Pudong working well of Shanghai West Changjiang Road Tunnel, the reason of being differences and lack of numerical simulation is analyzed, can propose a reasonable advice for the design of deep foundation.

Key words soft soil; super-deep foundation; monitoring analysis; finite element; deformation characteristics

目 錄

摘 要 I
Abstract III
第1章 緒論 1
1.1 引言 1
1.2國內外研究現狀 1
1.2.1 坑底回彈研究 2
1.2.2 坑周土體變形研究 3
1.2.3 基坑工程變形特性時間效應研究 5
1.2.4 土與支護結構的相互作用研究 6
1.3 本文研究的主要內容 7
第2章 軟土中大型深基坑工程實測研究 9
2.1 軟土及軟土地區(qū)基坑工程特點 9
2.2 工程概況 10
2.2.1 工程簡介 10
2.2.2 工程地質及水文地質概況 10
2.3 基坑支護設計方案 12
2.4 施工工況 13
2.5 監(jiān)測點的布設 14
2.5.1 監(jiān)測控制網的布設 14
2.5.2 浦東工作井監(jiān)測點的布設 14
2.6 監(jiān)測作業(yè)方法 17
2.6.1 控制測量 17
2.6.2 地下連續(xù)墻測斜 18
2.6.3 沉降觀測 19
2.6.4 支撐軸力監(jiān)測 19
2.7 監(jiān)測結果分析 20
2.7.1 連續(xù)墻側向位移 20
2.7.2 連續(xù)墻墻頂沉降 26
2.7.3 格構柱沉降 27
2.7.4 支撐軸力 28
2.7.5 墻后地表沉降 31
2.7.6 建筑物沉降監(jiān)測 33
2.8 本章小結 34
第3章 基坑開挖有限元分析 36
3.1本構模型 36
3.1.1 支護結構的本構模型 36
3.1.2 土體本構模型 36
3.2土與結構接觸單元模型 38-br..