【摘要】：隨著近年來西部大開發(fā)戰(zhàn)略的不斷推進(jìn),西部高寒地區(qū)公路和鐵路工程建設(shè)規(guī)模日漸擴(kuò)大。在寒區(qū)公路和鐵路工程建設(shè)過程中,修建了大量的隧道工程,然而在工程運(yùn)營過程中,普遍出現(xiàn)了不同程度的凍害問題。本文針對寒區(qū)隧道的凍害問題,分析了凍害產(chǎn)生的機(jī)理,研究了寒區(qū)隧道圍巖在凍融變化下的物理力學(xué)特性,推導(dǎo)了巖體的水、熱、力三場耦合控制方程,并以巴哈達(dá)坂公路隧道為背景,建立了水、熱、力三場耦合數(shù)學(xué)模型,對隧道建成后50年內(nèi)的溫度場、應(yīng)力場及變形場進(jìn)行模擬,計(jì)算分析了該隧道工程的變形可靠度和失效概率。主要內(nèi)容包括:(1)歸納分析寒區(qū)隧道的凍害現(xiàn)象,主要表現(xiàn)為:襯砌滲漏水、掛冰,地道翻漿冒泥、凍脹結(jié)冰,襯砌破裂,洞門墻開裂,排水系統(tǒng)凍結(jié)堵塞,洞口處巖體和積雪熱融滑塌等。(2)分析了隧道襯砌結(jié)構(gòu)的凍害機(jī)理。寒區(qū)隧道凍害產(chǎn)生的主要原因是隧道巖體內(nèi)部水分在溫度降低到水的冰點(diǎn)以下時(shí),水分凍結(jié)成冰產(chǎn)生體積膨脹對巖體和隧道襯砌產(chǎn)生凍脹力。(3)總結(jié)分析了溫度場、滲流場、應(yīng)力場耦合的基本理論,并建立了溫度場、滲流場、應(yīng)力場耦合控制方程。(4)以巴哈達(dá)坂隧道為背景,建立了溫度場、滲流場、應(yīng)力場耦合的數(shù)學(xué)模型,模擬分析了隧道建成后50年內(nèi)的溫度場、應(yīng)力場及變形場的變化規(guī)律。結(jié)果表明:(1)溫度場方面:隧道建成后第50年7月份,未鋪設(shè)保溫層隧道二次襯砌外側(cè)的溫度為5.26℃,鋪設(shè)保溫層隧道二次襯砌外側(cè)的溫度為1.64℃。未鋪設(shè)保溫層隧道圍巖的融化深度為2.0m,鋪設(shè)保溫層隧道融化深度為1.1m,由此可知,鋪設(shè)5cm厚的保溫層對該隧道降溫效果明顯。(2)應(yīng)力場方面:巴哈達(dá)坂隧道施工結(jié)束時(shí),仰拱底部最大拉應(yīng)力為0.32MPa,拱頂最大壓應(yīng)力為4.12MPa;隧道建成后第50年1月份,仰拱底部最大拉應(yīng)力為1.36MPa,拱頂最大壓應(yīng)力為5.67MPa,由此可知,隧道建成后第50年,隧道仰拱底部襯砌的最大拉應(yīng)力對隧道穩(wěn)定性有較大影響。(3)變形場方面:巴哈達(dá)坂隧道施工結(jié)束時(shí),隧道拱頂豎直向下的位移為2.07mm,仰拱豎直向上的位移為5.39mm;隧道建成后第50年1月份,拱頂豎直向下的位移為6.30mm,仰拱豎直向上的位移為9.32mm;隧道施工結(jié)束時(shí),隧道側(cè)墻的水平位移為2.98mm,隧道建成第50年1月份隧道側(cè)墻的水平位移為6.59mm。(5)在巴哈達(dá)坂隧道溫度場、應(yīng)力場及變形場分析的基礎(chǔ)上,采用響應(yīng)面法和驗(yàn)算點(diǎn)法,并編寫相應(yīng)的計(jì)算程序,計(jì)算分析了隧道建成后50年內(nèi)的可靠度指標(biāo)和失效概率。計(jì)算結(jié)果表明,在容許變形量為8mm的情況下,巴哈達(dá)坂隧道施工結(jié)束時(shí),隧道的可靠度指標(biāo)為4.5052,隧道的失效概率為0.0016%;隧道的可靠度指標(biāo)隨時(shí)間的推移不斷降低,隧道的失效概率不斷增加,且增長速率逐漸增大,巴哈達(dá)坂隧道建成后第50年的變形可靠度指標(biāo)為1.9736,相應(yīng)的失效概率為5.6900%。
[Abstract]:With the development of the western region in recent years, the construction scale of highway and railway in the western alpine region is expanding day by day. In the process of highway and railway construction in cold region, a large number of tunnel projects have been built. In this paper, the mechanism of freezing damage is analyzed, and the physical and mechanical properties of surrounding rock in freezing and thawing are studied. The coupling control equations of water, heat and force of rock mass are deduced. Taking the Bahadaban Highway Tunnel as the background, the coupled mathematical model of water, heat and force is established to simulate the temperature field, stress field and deformation field within 50 years after the tunnel is completed. The deformation reliability and failure probability of the tunnel are calculated and analyzed. The main contents are as follows: (1) the freezing damage phenomenon of the tunnel in cold region is summarized and analyzed, which are mainly manifested as follows: lining leakage, ice hanging, tunnel mudding, frost heaving and icing, lining cracking, portal wall cracking, drainage system freezing and blocking, The mechanism of freezing damage of tunnel lining is analyzed. The main cause of tunnel frost injury in cold region is that when the water content in tunnel rock mass decreases below the freezing point of water, the volume expansion of water frozen into ice produces frost heaving force on rock mass and tunnel lining. (3) the temperature field is summarized and analyzed. The coupling control equations of temperature field, seepage field and stress field are established. (4) the mathematical model of temperature field, seepage field and stress field coupling is established based on the Bahadaban Tunnel. The variation of temperature field, stress field and deformation field within 50 years after tunnel completion is simulated and analyzed. The results show that: (1) the temperature field of the tunnel is 5.26 鈩，

本文編號：2392291