發(fā)布時間：2018-04-14 01:09

  本文選題：膨脹性黃土隧道 + 大變形演化特征��； 參考：《山東大學》2014年碩士論文

【摘要】：自人類在黃土地區(qū)開展工程建設(shè)以來,黃土的力學特性及防護一直都是科學家們千百年來奮斗的科學問題。但由于在工程施工前期,對黃土膨脹特性及圍巖大變形機理認識不清,往往出現(xiàn)常規(guī)設(shè)計、施工無法保證隧道施工安全的問題。因此,研究膨脹性黃土隧道大變形演化特征,提出有效控制膨脹性黃土隧道大變形的支護技術(shù)是黃土地區(qū)隧道建設(shè)亟需解決的核心技術(shù)難題。本文依托2011年度鐵道部科技研究開發(fā)計劃課題“膨脹性黃土隧道大變形演化特征及施工關(guān)鍵技術(shù)研究”,以某膨脹性黃土隧道為工程背景,針對膨脹性黃土隧道大變形演化特征及支護對策的研究,采用了現(xiàn)場觀測、監(jiān)測試驗和數(shù)值模擬相結(jié)合的研究方法開展了相關(guān)研究。 (1)利用條分法分析隧道塌方與山體滑坡關(guān)系,對比研究隧道理論松動荷載值與實際圍巖壓力值,揭示出膨脹力是造成該隧道塌方的主要因子；基于收斂-約束理論,向圍巖特征曲線中引入膨脹力,建立了降雨誘發(fā)上覆濕陷性黃土濕陷開裂,形成入滲通道,引起隧道圍巖膨脹性黃土膨脹泥化,產(chǎn)生的膨脹力導(dǎo)致隧道常規(guī)支護強度不足,引起隧道膨脹性圍巖大變形演化發(fā)展,誘發(fā)大體積塌方的破壞模式。 (2)基于熱膨脹與增濕膨脹外在形式的相似性,利用ABAQUS具有的材料熱膨脹理論模擬了膨脹性黃土隧道洞周土體膨脹變形,基于強度折減法,開展了膨脹性黃土隧道在不同膨脹應(yīng)力作用下的隧道大變形演化過程研究,并求解了隧道圍巖儲備安全系數(shù),綜合現(xiàn)場實際記錄和數(shù)值模擬結(jié)果提出了相應(yīng)隧道初期支護施工建議。 (3)基于膨脹性黃土隧道的破壞模式及圍巖變形規(guī)律,提出了“鋼拱架+鋼格柵”聯(lián)合支護技術(shù)。利用前人的研究成果從不同角度分析了鋼拱架與鋼格柵的不同,利用數(shù)值模擬技術(shù)模擬了四種支護工況的支護性能,開展了“鋼拱架+鋼格柵”聯(lián)合支護機理研究。 (4)以太興鐵路某膨脹性黃土隧道為依托,工程應(yīng)用了“一榀型鋼拱架+一榀鋼格柵”的聯(lián)合支護技術(shù),通過拱架應(yīng)力監(jiān)測、現(xiàn)場圍巖變形監(jiān)測對聯(lián)合支護技術(shù)的支護效果進行了評價,評價結(jié)果表明聯(lián)合支護技術(shù)對膨脹性黃土隧道圍巖變形有良好的控制作用,可以應(yīng)用于現(xiàn)場實踐。
[Abstract]:The mechanical properties and protection of loess have been a scientific problem for thousands of years since the engineering construction was carried out in loess area.However, in the early stage of engineering construction, the problem of tunnel construction safety can not be guaranteed because of the unclear understanding of loess expansion characteristics and large deformation mechanism of surrounding rock, which is often caused by conventional design.Therefore, studying the evolution characteristics of large deformation of expansive loess tunnel and putting forward the supporting technology of controlling the large deformation of expansive loess tunnel is the key technical problem that needs to be solved in tunnel construction in loess area.In this paper, the engineering background of an expansive loess tunnel is based on the project of the Ministry of Railways Research and Development Program of Science and Technology in 2011, "study on the Evolution characteristics of large deformation and key Construction Technology of expansive Loess Tunnel", and take a certain expansive loess tunnel as the engineering background.Based on the study of evolution characteristics of large deformation and supporting countermeasures of expansive loess tunnel, the research methods of field observation, monitoring test and numerical simulation are used to carry out related research.1) analyze the relationship between tunnel collapse and landslide by slice method, compare the theoretical loosening load value with the actual surrounding rock pressure value, reveal that the expansion force is the main factor causing the tunnel collapse, based on the convergence-constraint theory,The expansion force is introduced into the characteristic curve of surrounding rock, the overlying collapsible loess collapsibility cracking induced by rainfall is established, and the infiltration channel is formed, which causes the swelling loess swelling mudding of surrounding rock of tunnel, which results in the insufficient conventional support strength of the tunnel.It leads to the evolution and development of large deformation of tunnel expansive surrounding rock and the failure mode of mass collapse.2) based on the similarity of the external forms of thermal expansion and humidification expansion, the swelling deformation of soil around the cavity of expansive loess tunnel is simulated by using the material thermal expansion theory of ABAQUS, which is based on the strength reduction method.In this paper, the evolution process of large deformation of expansive loess tunnel under different expansive stress is studied, and the safety factor of tunnel surrounding rock reserve is solved.Based on the actual site records and numerical simulation results, the corresponding initial supporting construction suggestions are put forward.Based on the failure mode of expansive loess tunnel and the deformation law of surrounding rock, the combined support technology of steel arch frame steel grid is put forward.The difference between steel arch frame and steel grid is analyzed from different angles by using the previous research results. The support performance of four kinds of supporting conditions is simulated by numerical simulation technology, and the mechanism of "steel arch frame steel grid" combined support is studied.Based on an expansive loess tunnel of Taixing railway, the combined support technology of "one steel arch frame and one steel grid" is applied in the project, and the stress of the arch frame is monitored.The effect of combined support technology is evaluated by monitoring the deformation of surrounding rock on site. The evaluation results show that the combined support technology has good control effect on surrounding rock deformation of expansive loess tunnel and can be applied to field practice.
【學位授予單位】：山東大學
【學位級別】：碩士
【學位授予年份】：2014
【分類號】：U451;U455.7

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本文編號：1747026