本文選題：地鐵　切入點(diǎn)：單洞雙線隧道　出處：《南京大學(xué)》2015年碩士論文

【摘要】：地鐵列車運(yùn)行引發(fā)周圍土體動(dòng)力響應(yīng),具體包括加速度、應(yīng)力、應(yīng)變、位移、孔隙水壓力等。越江地鐵隧道所穿越地層工程地質(zhì)條件復(fù)雜,地鐵運(yùn)行所引起的土體動(dòng)力響應(yīng)對(duì)土體工程性質(zhì)可能產(chǎn)生的影響不容忽視。目前,國內(nèi)外對(duì)單洞雙線地鐵隧道周圍土體動(dòng)力響應(yīng)研究尚未系統(tǒng)開展。南京地鐵10號(hào)線過江段為國內(nèi)首條穿越長江的單洞雙線盾構(gòu)隧道,本文以該區(qū)段近江北大堤斷面為例,采用PLAXIS 2D,對(duì)地鐵列車運(yùn)行引起隧道周圍土體的動(dòng)力響應(yīng)進(jìn)行了有限元模擬；同時(shí),對(duì)隧道下臥層砂土可液化性進(jìn)行了分析,得到了以下結(jié)論：(1)列車動(dòng)力作用使土體的動(dòng)力響應(yīng)呈周期性變化。在列車通過的時(shí)間內(nèi),出現(xiàn)了24個(gè)峰值,對(duì)應(yīng)于輪軌接觸過程中單趟列車的12個(gè)轉(zhuǎn)向架、24個(gè)輪對(duì)的沖擊作用。(2)在列車動(dòng)荷載作用的時(shí)間內(nèi),隧道下臥層、拱腰位置,加速度隨著距隧道中心距離的增加而衰減。地表加速度在傳播過程中,水平方向距離隧道中心10m處出現(xiàn)一個(gè)極大值。(3)單線工況隧道基底以下動(dòng)應(yīng)力的最大值為3.6kPa,雙線工況隧道基底以下動(dòng)應(yīng)力最大值約為7.2kPa,雙線工況所產(chǎn)生的土體動(dòng)應(yīng)力最大值約為單線工況土體動(dòng)應(yīng)力最大值的2倍,動(dòng)應(yīng)力在隧道基底以下5m范圍內(nèi)衰減較快,且隨深度呈指數(shù)型衰減。(4)單線工況基底土體壓應(yīng)變明顯小于雙線工況下的土體壓應(yīng)變,雙線工況基底土體回彈應(yīng)變大于單線工況下的回彈應(yīng)變。(5)單線工況下基底超靜孔隙水壓力峰值約為2.5kPa,雙線工況下的峰值約為5kPa,且基底超孔隙水壓力最大值隨距離的增加呈指數(shù)型減小。(6)隧道下臥層孔隙水壓力與總應(yīng)力的比值在0.6左右波動(dòng),下臥層粉砂層不會(huì)發(fā)生液化。
[Abstract]:The dynamic response of surrounding soil is caused by train operation, including acceleration, stress, strain, displacement, pore water pressure and so on.The engineering geological conditions of the tunnel crossing the river are complex, and the influence of the dynamic response of the soil caused by the subway operation on the engineering properties of the soil can not be ignored.At present, the research of soil dynamic response around single tunnel and double line subway tunnel has not been carried out systematically at home and abroad.The crossing section of Nanjing Metro Line 10 is the first single-hole double-line shield tunnel across the Yangtze River in China. This paper takes the section of this section near the north of the Yangtze River as an example.Using PLAXIS 2D, the dynamic response of soil around the tunnel caused by subway train operation is simulated by finite element method, and the liquefaction of sand under tunnel is analyzed.The following conclusions are obtained: 1) the dynamic response of soil is periodically changed by train dynamic action.Within the train passing time, 24 peaks appear, corresponding to 12 bogies and 24 wheelsets of a single train during wheel-rail contact.The acceleration decreases with the increase of the distance from the center of the tunnel.In the course of ground acceleration propagation,A maximum value appeared in the horizontal direction 10 m from the center of the tunnel.) the maximum value of dynamic stress below the base of the tunnel is 3.6 KPA under the single-line working condition, and the maximum value of the dynamic stress under the base of the double-line working condition is about 7.2 KPA, and the dynamic response of the soil produced by the double-line working condition is about 7.2 KPA.The maximum value of force is about 2 times that of the maximum dynamic stress of soil under single line working condition.The dynamic stress attenuation is faster in the range of 5m below the tunnel base, and it is exponentially attenuated with the depth of the tunnel, and the compressive strain of the foundation soil under the single line condition is obviously smaller than that of the soil under the double line working condition.The springback strain of soil in double line working condition is larger than that in single line condition.) the peak value of excess pore water pressure in single line condition is about 2.5 KPA, the peak value in double line condition is about 5 KPA, and the maximum value of excess pore water pressure in basement is with distance.The ratio of pore water pressure to total stress fluctuates around 0.6.There is no liquefaction of the silt layer in the underlying layer.
【學(xué)位授予單位】：南京大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2015
【分類號(hào)】：U452.11;U231.1

【引證文獻(xiàn)】

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1 劉志亭;;跨海通道:橋梁與隧道的系統(tǒng)評(píng)價(jià)與決策——以青島膠州灣口跨海通道為例[A];中國企業(yè)運(yùn)籌學(xué)[2013(1)][C];2013年

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本文編號(hào)：1713360