【摘要】：隨著西部大開發(fā)戰(zhàn)略穩(wěn)步實施，我國交通基礎(chǔ)設(shè)施建設(shè)得到了高速發(fā)展，給公路建設(shè)帶來了前所未有的機(jī)遇和挑戰(zhàn)。由于隧道工程具有獨特的優(yōu)勢，因而在公路工程中被廣泛的應(yīng)用，并且取得了良好的社會經(jīng)濟(jì)效益。但是由于隧道支護(hù)結(jié)構(gòu)通常所處的地質(zhì)環(huán)境條件一般都比較復(fù)雜，，圍巖力學(xué)參數(shù)指標(biāo)、計算模式、荷載和結(jié)構(gòu)抵抗能力等比較難確定，使得目前采用傳統(tǒng)的隧道支護(hù)結(jié)構(gòu)的設(shè)計方法難以同時兼顧斷面形式的經(jīng)濟(jì)合理性和支護(hù)結(jié)構(gòu)的穩(wěn)定性，具有一定的盲目性。因此，用結(jié)構(gòu)可靠度理論來研究分析隧道支護(hù)結(jié)構(gòu)的穩(wěn)定可靠性，使隧道設(shè)計更加合理、科學(xué)，減少運營期間隧道的安全隱患，具有十分重要的實踐和理論意義。 本文在大量閱讀和參考國內(nèi)外相關(guān)文獻(xiàn)的基礎(chǔ)上，依托國家高速公路網(wǎng)鄖縣至十堰高速公路大華山隧道，通過對隧道區(qū)工程地質(zhì)條件的研究，結(jié)合現(xiàn)場對圍巖拱頂下沉和洞周收斂變形的監(jiān)測，并對監(jiān)測數(shù)據(jù)進(jìn)行處理分析，利用FLAC3D建立隧道模型，對大華山隧道施工開挖過程中圍巖應(yīng)力應(yīng)變特征進(jìn)行分析，為施工中采用合理的支護(hù)提供依據(jù)。同時，建立功能函數(shù)及各參變量分布形態(tài)，采用蒙特卡羅法對大華山隧道支護(hù)結(jié)構(gòu)進(jìn)行可靠度研究。本文的主要內(nèi)容和取得成果如下： （1）深入研究了隧道開挖過程中力學(xué)特性，分析了圍巖應(yīng)力、應(yīng)變的變化過程，從地質(zhì)因素、工程因素兩大方面分析了影響大華山隧道圍巖穩(wěn)定性的不利因素，得出地下水、時間因素對大華山圍巖穩(wěn)定性影響比較大。 （2）分析了隧道支護(hù)結(jié)構(gòu)失穩(wěn)破壞的原因和收斂比、變形速率比值、容許極限位移和變形速率與加速度等四種常用失穩(wěn)判據(jù)，在此基礎(chǔ)上通過對大華山隧道Ⅳ級與Ⅲ級圍巖的相交圍巖段的圍巖變形監(jiān)測數(shù)據(jù)進(jìn)行回歸分析，得出此段圍巖變形趨于穩(wěn)定的時間節(jié)點為27天左右，為隧道二襯施作時間提供參考依據(jù)。 （3）采用FLAC3D軟件對大華山隧道施工過程進(jìn)行了數(shù)值模擬，對開挖過程中隧道的應(yīng)力、應(yīng)變進(jìn)行了分析，得出隧道位移變形量與現(xiàn)場監(jiān)測數(shù)據(jù)基本一致。并找出隧道拱腰（上下臺階開挖分界處）、拱頂和拱腳部位是圍巖穩(wěn)定性的薄弱部位，為隧道后續(xù)施工和監(jiān)測提供指導(dǎo)。 （4）基于MATLAB軟件采用蒙特卡洛算法和設(shè)計驗算點法計算比較各種工況下的可靠指標(biāo)并對其分析，得出隧道支護(hù)結(jié)構(gòu)是穩(wěn)定的，采用的支護(hù)結(jié)構(gòu)是合理的，為大華山特長隧道圍巖穩(wěn)定性評價及其支護(hù)技術(shù)提供理論依據(jù)和科學(xué)指導(dǎo)，也對其他類似工程施工有一定的借鑒和指導(dǎo)意義。
[Abstract]:With the steady implementation of the strategy of western development, the construction of transportation infrastructure in China has been developing at a high speed, which has brought unprecedented opportunities and challenges to highway construction. Because of its unique advantages, tunnel engineering has been widely used in highway engineering, and has achieved good social and economic benefits. However, because the geological environment of tunnel support structure is usually complicated, it is difficult to determine the mechanical parameters of surrounding rock, the calculation model, the load and the resistance of the structure, etc. It is difficult to take account of the economic rationality of section form and the stability of supporting structure at the same time because of the traditional design method of tunnel support structure, which is blind to a certain extent. Therefore, it is of great practical and theoretical significance to use the theory of structural reliability to study and analyze the stability and reliability of tunnel support structure, to make the tunnel design more reasonable and scientific, and to reduce the hidden danger of tunnel safety during operation. On the basis of reading and referring to domestic and foreign related documents, this paper, relying on the national highway network Yun county to Shiyan highway Dahuashan tunnel, through the study of the tunnel area engineering geological conditions, Combined with the site monitoring of surrounding rock arch roof subsidence and convergence deformation around the tunnel, the monitoring data are processed and analyzed, and the tunnel model is established by using FLAC3D to analyze the stress and strain characteristics of surrounding rock during the construction and excavation of Dahuashan Tunnel. It provides the basis for reasonable support in construction. At the same time, the function and the distribution form of each parameter are established, and the reliability of the supporting structure of Dahuashan tunnel is studied by Monte Carlo method. The main contents and achievements of this paper are as follows: (1) the mechanical characteristics of tunnel excavation are deeply studied, and the variation process of stress and strain of surrounding rock is analyzed. The unfavorable factors affecting the stability of surrounding rock of Dahuashan Tunnel are analyzed in two aspects of engineering factors. It is concluded that the groundwater and time factors have great influence on the stability of surrounding rock of Dahua Mountain. (2) the causes and convergent ratio, the ratio of deformation rate, the allowable limit displacement and deformation rate and acceleration are analyzed. On this basis, through the regression analysis of the surrounding rock deformation monitoring data of the intersection of grade 鈪

本文編號：2320429