本文選題：季節(jié)性凍土　切入點：隧道　出處：《中國鐵道科學(xué)研究院》2014年碩士論文　論文類型：學(xué)位論文

【摘要】：隧道襯砌裂縫在季節(jié)性凍土隧道中的大量存在，嚴(yán)重影響了隧道襯砌結(jié)構(gòu)的穩(wěn)定性、適用性、耐久性，且襯砌裂縫的進一步發(fā)展同時會誘發(fā)其它隧道病害，影響到隧道的安全性。本文以梁家坪2#隧道工程為依托，從現(xiàn)場的試驗監(jiān)測出發(fā)，通過運用大型通用有限元軟件ANSYS，對季節(jié)性凍土隧道溫度場、應(yīng)力場進行計算和分析。并對季節(jié)性凍土隧道襯砌開裂機理進行研究分析，為預(yù)防和治理此類病害隧道提供理論參考。主要結(jié)論如下： （1）由梁家坪2#隧道室內(nèi)實驗可得：圍巖含水量約為10.8%，飽和原狀土樣的含水量則約為12.3%，圍巖飽水自由凍脹率約為1.41%，泥巖自由膨脹率為15%，砂巖自由膨脹率為8%，根據(jù)規(guī)范圍巖屬非膨脹土。 （2）在對能夠造成襯砌開裂的可能性原因分析的基礎(chǔ)上，排除了由高地應(yīng)力、水壓力、膨脹土壓力、圍巖壓力等因素導(dǎo)致該隧道開裂的可能性。通過對梁家坪2#隧道進行現(xiàn)場試驗監(jiān)測分析，發(fā)現(xiàn)邊墻縱向裂縫的變化規(guī)律符合由圍巖凍脹導(dǎo)致襯砌開裂的變化規(guī)律。因此，初步判斷該隧道襯砌開裂的主要原因是由于圍巖的季節(jié)性凍脹所引起。 （3）通過對該地區(qū)的氣溫、降雨統(tǒng)計分析可知，近幾年該地區(qū)夏季雨量比較豐富，冬季氣溫比較低，負(fù)溫持續(xù)時間達(dá)4個月左右，最冷月份平均氣溫在-10℃左右。 （4）隧道溫度場數(shù)值計算結(jié)果表明圍巖凍結(jié)圈深度為104cm，與實測100cm基本相符合，且最大凍結(jié)深度發(fā)生的時間均在次年的1月19日前后。 （5）由凍脹力計算結(jié)果可知，梁家坪2#隧道在凍脹力作用下隧道邊墻處拉應(yīng)力大于混凝土極限抗拉強度，與實際病害相符。 （6）通過對不同圍巖凍結(jié)圈下隧道襯砌配筋設(shè)計得出，隧道襯砌配筋面積與圍巖凍結(jié)圈深度呈線性關(guān)系。因此對于在季節(jié)性凍土區(qū)修建隧道應(yīng)考慮凍脹設(shè)防。 （7）通過對三種不同方案的配筋加固方案設(shè)計，，建議采用第三種方案即切槽放鋼筋籠，并在隧道邊墻受拉區(qū)范圍內(nèi)上下各打設(shè)3根Φ25錨桿，以抵抗季節(jié)凍脹力，抑制邊墻向隧道內(nèi)擠出，防止襯砌進一步開裂。同時在隧道襯砌背后進行注漿（其注漿范圍為0.6m～0.8m）加固，以減小土體孔隙率，減小圍巖存水空隙，降低圍巖凍脹率，進而有效減小圍巖凍脹。
[Abstract]:The existence of tunnel lining cracks in seasonal permafrost tunnels seriously affects the stability, applicability and durability of tunnel lining structures, and the further development of lining cracks will induce other tunnel diseases at the same time. Based on the Liangjiaping2# tunnel project, the temperature field of the seasonal frozen soil tunnel is studied by using the large-scale finite element software ANSYS. based on the field test and monitoring. The stress field is calculated and analyzed, and the cracking mechanism of tunnel lining in seasonal frozen soil is studied and analyzed, which provides a theoretical reference for the prevention and treatment of this kind of disease tunnel. The main conclusions are as follows:. (1) the indoor experiment of Liangjiaping2# tunnel shows that the water content of surrounding rock is about 10.8, the water content of saturated undisturbed soil is about 12.3, the free frost heaving rate of surrounding rock is about 1.41, the free expansion rate of mudstone is 15, the free expansion rate of sandstone is 8. The range of rock is non-expansive soil. (2) on the basis of the analysis of the possible causes of the cracking of the lining, the high ground stress, water pressure and expansive soil pressure are excluded. The possibility of cracking in the tunnel caused by surrounding rock pressure and other factors. Through field test and analysis of Liangjiaping2# tunnel, it is found that the variation law of longitudinal crack of sidewall conforms to the variation law of lining cracking caused by frost heaving of surrounding rock. The main reason for the tunnel lining cracking is the seasonal frost heaving of surrounding rock. 3) through the statistical analysis of the temperature and rainfall in this area, it can be seen that the summer rainfall in this area is relatively abundant in recent years, the winter temperature is relatively low, the negative temperature lasts for about 4 months, and the average temperature in the coldest month is about -10 鈩

本文編號：1632388