甫當隧道溫度應(yīng)力場數(shù)值模擬分析
發(fā)布時間：2018-06-06 13:41
本文選題：鐵路隧道 + 高地?zé)?/strong>�。� 參考：《蘭州交通大學(xué)》2015年碩士論文
【摘要】：近幾年來國家大力發(fā)展鐵路市場,來帶動國家經(jīng)濟的發(fā)展。國內(nèi)高速鐵路里程的日益增長,使得設(shè)計師們越來越多的使用橋梁與隧道來征服高山、跨越峽谷。隧道,作為線路中的一種常見的建筑結(jié)構(gòu)形式,近幾年來更是被廣泛的應(yīng)用,而且隧道的長度也在不斷的增加。長大隧道的出現(xiàn)及長度的不斷增長,在給線路選線工作提供便利的同時,以前不太明顯的隧道病害,逐漸成為影響隧道施工及運營的重要因素。高地?zé)釂栴}就是近年來逐漸開始顯現(xiàn)的一種隧道病害—地溫場對隧道結(jié)構(gòu)的影響程度也明顯的提高。本文以高海拔、高地溫的拉日線甫當隧道為依托,根據(jù)傳熱學(xué)所學(xué)的相關(guān)理論知識,運用ANSYS對現(xiàn)場實際情況進行數(shù)值模擬,分析了在施加了溫度荷載的前后,二次襯砌結(jié)構(gòu)的受力情況及安全系數(shù),決定使用隔熱材料來阻礙地層中熱量流向隧道二次襯砌結(jié)構(gòu)。結(jié)合現(xiàn)場實際情況,經(jīng)過綜合比選,確定了隔熱層的材料種類和施做厚度。然后分兩階段—施工階段及運營階段對隧道進行通風(fēng)降溫,并計算運營期間二次襯砌內(nèi)的應(yīng)力及安全系數(shù),確保隧道在施工過程中及使用年限內(nèi)都有足夠的可靠性。(1)運用ANSYS軟件,分別計算分析甫當隧道二次襯砌結(jié)構(gòu)僅在溫度場和在溫度應(yīng)力場耦合作用下,應(yīng)力分布特征及安全系數(shù)情況。結(jié)果顯示,溫度對結(jié)構(gòu)內(nèi)力影響較大,結(jié)構(gòu)的安全系數(shù)降低。(2)分別模擬結(jié)構(gòu)在施做隔熱層前后,隧道二次襯砌內(nèi)部結(jié)點溫度情況。計算結(jié)果表明在施做隔熱層后,二次襯砌結(jié)構(gòu)的溫度提升速率更為平緩,且在計算年限之內(nèi),隧道二次襯砌溫度明顯降低。(3)模擬分析不同材質(zhì)及不同厚度的隔熱層,結(jié)合實際情況,以經(jīng)濟合理為原則,選擇最優(yōu)隔熱層施做方案—在二次襯砌及復(fù)合防水層之間,施做10cm厚復(fù)合型硅酸鹽隔熱層,來阻礙地層中熱量流向隧道二次襯砌結(jié)構(gòu)。(4)考慮隧道貫通以前,隧道內(nèi)部空氣與隧道外空氣對流不明顯,為保證施工人員的安全,施工機械設(shè)備的正常運作,決定使用通風(fēng)機對隧道進行通風(fēng)降溫處理。模擬計算結(jié)果顯示,當空氣溫度15℃、風(fēng)管內(nèi)風(fēng)速大于15米/秒時,距離掌子面110米的范圍內(nèi),隧道內(nèi)部氣溫下降到30℃以內(nèi)。(5)運營過程中,假設(shè)隧道內(nèi)空氣充分與洞外空氣對流,計算結(jié)果顯示,隧道二次襯砌結(jié)構(gòu)在隧道內(nèi)氣溫及隔熱層的作用下,較不采取任何降溫措施情況下,結(jié)構(gòu)內(nèi)部應(yīng)力有所降低,整體安全性提高,運營通風(fēng)滿足要求。
[Abstract]:In recent years, the country has vigorously developed the railway market to drive the development of the national economy. With the increasing mileage of domestic high-speed railway, designers use bridges and tunnels to conquer mountains and cross canyons. Tunnel, as a common architectural structure, has been widely used in recent years, and the length of tunnel is increasing. With the appearance of long tunnel and the increasing length of long tunnel, it is convenient for the route selection work, but the tunnel disease, which was not obvious in the past, has gradually become an important factor affecting the tunnel construction and operation. The high geothermal problem is a kind of tunnel disease which gradually appears in recent years-the influence degree of the ground temperature field on the tunnel structure is also obviously improved. In this paper, based on the high altitude and high ground temperature pullout tunnel, according to the relevant theoretical knowledge of heat transfer, using ANSYS to carry out the numerical simulation of the actual situation in the field, the analysis is made before and after the temperature load is applied. Because of the stress and safety factor of the secondary lining structure, it is decided to use the heat insulation material to block the heat flow to the tunnel secondary lining structure. According to the actual situation in the field, the material types and the thickness of the heat insulation layer are determined by comprehensive comparison and selection. Then the tunnel is ventilated and cooled in two stages-construction phase and operation stage, and the stress and safety factor in the secondary lining during operation are calculated. To ensure that the tunnel has sufficient reliability during construction and service life. (1) using ANSYS software to calculate and analyze the secondary lining structure of the tunnel only under the coupling of temperature field and temperature stress field. Stress distribution and safety factor. The results show that the temperature has a great influence on the internal force of the structure, and the safety factor of the structure is reduced. 2) respectively, the temperature of the inner node of the tunnel secondary lining is simulated before and after the construction of the thermal insulation layer. The calculation results show that the temperature rise rate of the secondary lining structure is more gentle after the application of the heat insulation layer, and the temperature of the secondary lining of the tunnel decreases obviously within the calculated years. (3) the heat insulation layer of different materials and thickness is simulated and analyzed. In combination with the actual situation and taking the principle of economy and rationality as the principle, the best heat insulation layer is chosen-between the secondary lining and the composite waterproof layer, the 10cm thick composite silicate insulation layer is applied. To block the flow of heat in the formation to the secondary lining structure of the tunnel. (4) considering that before the tunnel is through, the convection between the air inside the tunnel and the air outside the tunnel is not obvious. In order to ensure the safety of the construction personnel, the normal operation of the construction machinery and equipment is ensured. It was decided to use ventilator for ventilation and cooling of tunnel. The simulation results show that, when the air temperature is 15 鈩，
本文編號：1986747
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