【摘要】：外海大回淤沉管隧道軟基沉降特性及計算目前尚無比較成熟的經(jīng)驗可資借鑒，但其地基的沉降計算方法及參數(shù)取值、沉降控制對隧道設計和施工都具重要意義。論文通過現(xiàn)場試驗測試與室內(nèi)模型試驗相結合的方法，提出一套有效應用于沉降計算的參數(shù)取值方法；建立了符合施工工序的沉管隧道地基沉降計算方法；通過離心試驗的定性分析與沉降的定量計算，，揭示了沉管隧道天然地基的回彈再壓縮沉降特性；結合蒙特卡羅概率有限元方法，進行巖土參數(shù)變異性、施工偏差及回淤量對沉降影響的敏感性分析；建立考慮不均勻土層下的彈性地基梁計算力學模型，推導了沉管隧道沉降控制計算方法，為沉管隧道的基礎方案設計與優(yōu)化及施工工藝改進提供了重要支撐。 1.基于現(xiàn)場測試數(shù)據(jù)資料分析，依據(jù)模型相似理論和滲透固結理論，提出了模擬完整施工工序的小比尺離心模型試驗方案；結合工程實際及離心力場特性，確定了離心模型試驗中離心機加速度；選用特種有機玻璃為沉管材料，對其幾何尺寸進行部分修正，實現(xiàn)了模型與原型承力的相似；布設高靈敏度及高精密測試元件。試驗結果揭示了不同墊層厚度下基底應力變形變化及沉管應變分布規(guī)律，也為下一步小探頭CPTU試驗及室內(nèi)常規(guī)試驗提供土樣條件。 2.地基參數(shù)的確定決定沉降計算結果精度，為能快捷的獲取準確計算參數(shù)，且減小土樣采集制備過程產(chǎn)生的誤差，論文分別開展了2cm2和15cm2探頭CPTU原位測試，并借以2cm2探頭CPTU測試結果，擬合出CPTU原位測試數(shù)據(jù)與土性參數(shù)間的回歸公式，由此建立了由CPTU原位測試確定的海底特殊地層土性參數(shù)指標的計算方法，用以確定后期的計算參數(shù)。 3.基于計算參數(shù)確定方法，考慮沉管隧道基槽開挖、墊層鋪設、隧管沉放、管頂回淤、航道開挖等整個施工過程，建立模擬施工過程的有限元計算模型及沉降簡化計算模型，揭示了沉管隧道天然地基沉降特性，明確了回填-沉管-地基間的相互作用機理，確定縱向地基剛度變化較大區(qū)段。 4.結合傳統(tǒng)的有限元計算分析方法及蒙特卡羅理論，基于Spearman秩相關系數(shù)的靈敏度分析方法，對沉管隧道下臥土層的巖土參數(shù)變異性、可能的施工偏差及回淤量等因素對地基橫向及縱向沉降的影響敏感性進行分析，確定了敏感性較大的影響因素，得出了對沉降影響的最不利工況組合及分布形式，為施工控制提供參考。 5.結合彈性地基梁理論，建立考慮不均勻土層情況下的彈性地基梁計算力學模型，計算出隧道縱向位移曲線方程及隧道某一位置截面的剪力，推導沉管隧道沉降控制標準計算公式，為基礎方案設計優(yōu)化及施工工藝改進措施提供條件。
[Abstract]:At present, there is no mature experience to learn from the settlement characteristics and calculation of soft foundation of large silting pipe tunnel in the outer sea, but the settlement calculation method, parameter value and settlement control of the foundation are of great significance to tunnel design and construction. Through the combination of field test and indoor model test, this paper puts forward a set of parameter value method which is effectively applied to settlement calculation, and establishes a settlement calculation method of immersed pipe tunnel foundation in accordance with the construction process. Through the qualitative analysis of centrifugal test and the quantitative calculation of settlement, the springback and compression settlement characteristics of natural foundation of immersed pipe tunnel are revealed. Combined with Monte Carlo probabilistic finite element method, the sensitivity analysis of geotechnical parameter variability, construction deviation and siltation amount on settlement is carried out. The computational mechanical model of elastic foundation beam considering uneven soil layer is established, and the calculation method of settlement control of immersed pipe tunnel is deduced, which provides important support for the design and optimization of foundation scheme and improvement of construction technology of immersed pipe tunnel. 1. Based on the analysis of field test data, according to the model similarity theory and osmotic consolidation theory, a small scale centrifugal model test scheme is proposed to simulate the complete construction process. Combined with the engineering practice and the characteristics of centrifugal force field, the acceleration of centrifuge in centrifugal model test is determined, and the geometric size of special plexiglass is partly modified to realize the similarity between the model and the prototype. High sensitivity and high precision test elements are arranged. The test results reveal the variation of foundation stress and deformation and the strain distribution of sinking pipe under different cushion thickness, and also provide soil sample conditions for the next step of small probe CPTU test and laboratory routine test. 2. The determination of foundation parameters determines the accuracy of settlement calculation results. In order to obtain accurate calculation parameters quickly and reduce the error caused by soil sample collection and preparation process, 2cm2 and 15cm2 probe CPTU in situ tests are carried out in this paper. Based on the CPTU test results of 2cm2 probe, the regression formula between CPTU in situ test data and soil property parameters is fitted, and the calculation method of soil property parameters in special formation of seafloor determined by CPTU in situ test is established. Used to determine the later calculation parameters. 3. Based on the method of determining the calculation parameters, considering the whole construction process, such as foundation groove excavation, cushion laying, tunnel pipe subsidence, pipe top silting, channel excavation and so on, the finite element calculation model and the simplified settlement calculation model are established to simulate the construction process. The settlement characteristics of the natural foundation of the immersed pipe tunnel are revealed, the interaction mechanism between the backfill, the sinking pipe and the foundation is clarified, and the section with large variation of longitudinal foundation stiffness is determined. 4. Combined with the traditional finite element calculation and analysis method and Monte Carlo theory, based on the sensitivity analysis method of Spearman rank correlation coefficient, the variability of geotechnical parameters in the underlying soil layer of immersed pipe tunnel is studied. The influence sensitivity of the possible construction deviation and siltation amount on the transverse and longitudinal settlement of the foundation is analyzed, the sensitive factors are determined, and the most unfavorable working condition combination and distribution form of the influence on the settlement are obtained. Provide reference for construction control. 5. Based on the elastic foundation beam theory, the computational mechanics model of the elastic foundation beam considering the uneven soil layer is established, and the longitudinal displacement curve equation of the tunnel and the shear force of a section of the tunnel at a certain position are calculated. The calculation formula of settlement control standard for immersed pipe tunnel is derived, which provides conditions for the design optimization of foundation scheme and the improvement of construction technology.
【學位授予單位】：長安大學
【學位級別】：博士
【學位授予年份】：2014
【分類號】：U452.11;U459.5

【參考文獻】

相關期刊論文 前10條

1 林永國,廖少明,劉國彬;地鐵隧道縱向變形影響因素的探討[J];地下空間;2000年04期

2 韋凱;雷震宇;周順華;;盾構隧道下穿地下管線的變形控制因素分析[J];地下空間與工程學報;2008年02期

3 馮震;王娜;王連俊;;沉降組合預測模型研究及其應用[J];北京交通大學學報;2008年01期

4 張延軍,張延詰;海積軟土彈粘塑性Biot固結的數(shù)值分析[J];吉林大學學報(地球科學版);2003年01期

5 周衛(wèi);基于MATLAB的灰色系統(tǒng)沉降預測[J];測繪通報;2002年06期

6 包承綱,饒錫保;土工離心模型的試驗原理[J];長江科學院院報;1998年02期

7 白冰,周健;土工離心模型試驗技術的一些進展[J];大壩觀測與土工測試;2001年01期

8 姜啟元,管攀峰,葉蓉;軟土盾構隧道的縱向變形分析[J];地下工程與隧道;1999年04期

9 梅甫良,曾德順;沉管隧道的進展[J];地下工程與隧道;2002年04期

10 韓立忠;地鐵越江隧道地基沉降的離心模型試驗分析[J];地下工程與隧道;2005年03期

相關博士學位論文 前4條

1 李建民;超深超大基坑回彈變形計算方法的試驗研究[D];中國建筑科學研究院;2010年

2 謝桂華;巖土參數(shù)隨機性分析與邊坡穩(wěn)定可靠度研究[D];中南大學;2009年

3 張莎莎;基于離心模型試驗的飽和土固結理論研究[D];長安大學;2011年

4 楊茜;盾構隧道縱向不均勻沉降及實時監(jiān)測方法研究[D];北京交通大學;2013年

本文編號：2472946