本文關(guān)鍵詞： 超淺埋 超大斷面 軟土隧道 ANSYS 三次襯砌　出處：《武漢工程大學(xué)》2014年碩士論文　論文類型：學(xué)位論文

【摘要】：研究以某穿越軟土地層超大斷面、超淺埋雙層公路隧道為例，系統(tǒng)的研究了該地層下隧道的開挖支護(hù)形式，對開挖過程中的臨時支護(hù)、初期支護(hù)及二次襯砌進(jìn)行了數(shù)值模擬，同時對三次襯砌的強(qiáng)度和穩(wěn)定性進(jìn)行了分析，分析對比了兩種中板連接形式的優(yōu)劣。 首先對超淺埋、超大斷面的隧道的發(fā)展以及研究現(xiàn)狀進(jìn)行了分析，對現(xiàn)有隧道圍巖計算理論進(jìn)行了分析歸納，然后系統(tǒng)的介紹了拱北隧道的開挖支護(hù)方法，包括超前支護(hù)，冷凍法，注漿工法等。對隧道所采用的臨時支護(hù)、初期支護(hù)、二次襯砌及三次襯砌進(jìn)行了介紹。利用ANSYS有限元程序建立平面模型對隧道開挖支護(hù)的全過程進(jìn)行了模擬分析，對開挖過程中土體的應(yīng)力場和位移場進(jìn)行了分析，對臨時支撐、初期支護(hù)和二次襯砌的內(nèi)力進(jìn)行分析，并對該種地質(zhì)情況下的超前支護(hù)與初期支護(hù)的改進(jìn)措施進(jìn)行了初步的探討，得出結(jié)論： （1）隧道開挖時是做了型鋼臨時支撐，由分析計算可知，豎向支撐的軸力是由上到下越來越來大，且豎向臨時支撐的軸力較橫向臨時支撐大，故應(yīng)采用的豎向支撐要比橫向支撐強(qiáng)度，剛度大。 （2）水平臨時支撐與豎向臨時支撐都要承受一定的彎矩，特別是橫向與豎向支撐的連接節(jié)點處彎矩較大，所以施工時必須重視該節(jié)點的連接精度、連接強(qiáng)度與剛度，，以防止支撐在受彎時節(jié)點張開影響施工時的安全。 （3）隨著隧道臺階的開挖進(jìn)行，土體的塑性區(qū)也在向深部發(fā)展。第四臺階的開挖后，隧道拱頂圍巖除豎向支撐的支撐點附近外，均進(jìn)入受拉區(qū)，且受拉區(qū)的影響的區(qū)域變大，故在隧道施工中應(yīng)密切關(guān)注第四臺階的開挖，提前做好防范措施。 利用ANSYS對施工期間和運營期間的三次襯砌的強(qiáng)度進(jìn)行了分析檢算，對中板與邊墻的連接形式進(jìn)行了研究分析，同時對三次襯砌的施工及設(shè)計提出了建議。 最后對該隧道的設(shè)計與施工進(jìn)行了總結(jié)，并對城市超淺埋大斷面隧道的設(shè)計及研究提出了建議：對于穿越城市密集建筑及政治敏感區(qū)的隧道，若不能封閉地面交通，采用雙層暗挖隧道結(jié)構(gòu)是可行的。由于受到地面交通的影響，加之隧道本身的開挖跨度大、埋深小、地質(zhì)條件差，由隧道開挖引起的地層損失可能引起地表沉陷甚至冒頂，故隧道開挖前采取強(qiáng)有力的超前支護(hù)措施是必要的。超前管幕法的使用可以最大限度的減少地面沉降，并減低地面交通對隧道開挖的影響，可以推廣使用。同時配合冷凍法和洞內(nèi)注漿加固，可保施工期間的安全。同時也指出了有待進(jìn)一步研究的問題： 研究采用數(shù)值分析是基于設(shè)計施工提出的，能基本反映隧道在施工過程中力學(xué)動態(tài)，可為類似隧道工程的設(shè)計與施工提供參考。
[Abstract]:Taking a super-large section and super-shallow double-layer highway tunnel through soft soil as an example, this paper systematically studies the excavation support form of the tunnel under the stratum, and simulates the temporary support, the initial support and the secondary lining during the excavation process. At the same time, the strength and stability of the third lining are analyzed, and the advantages and disadvantages of the two kinds of medium plate connection are analyzed and compared. First of all, the development and research status of super-shallow buried tunnel and super-section tunnel are analyzed, and the calculation theory of surrounding rock of existing tunnel is analyzed and summarized. Then, the excavation and support methods of Gongbei tunnel are introduced systematically, including advance support. Freezing method, grouting method and so on. This paper introduces the temporary support, initial support, secondary lining and third lining used in tunnel. The whole process of tunnel excavation support is simulated and analyzed by using ANSYS finite element program to establish plane model. The stress field and displacement field of soil during excavation are analyzed, and the internal forces of temporary bracing, initial support and secondary lining are analyzed. The improvement measures of advance support and initial support under this kind of geological condition are discussed preliminarily, and the conclusion is drawn:. The axial force of vertical bracing is more and more large from top to bottom, and the axial force of vertical temporary bracing is larger than that of lateral temporary bracing. Therefore, the vertical support should be used than the transverse support strength, stiffness. 2) both horizontal temporary support and vertical temporary support have to bear some bending moment, especially the moment at the connection joint of horizontal and vertical support is large, so we must pay attention to the connection precision, connection strength and stiffness of the joint during construction. To prevent the support in the bending of the joint opening to affect the safety of construction. 3) with the excavation of the tunnel steps, the plastic zone of the soil is also developing to the deep. After the excavation of the 4th steps, the surrounding rock of the tunnel arch all enter the tensile zone except near the supporting point of vertical support, and the area affected by the tensile zone becomes larger. Therefore, the excavation of 4th steps should be paid close attention to in tunnel construction, and preventive measures should be taken in advance. This paper analyzes and calculates the strength of the third lining during construction and operation by using ANSYS, studies and analyzes the connection form between the plate and the side wall, and puts forward some suggestions for the construction and design of the third lining. Finally, the paper summarizes the design and construction of the tunnel, and puts forward some suggestions on the design and study of the super-shallow tunnel with large section: if the ground traffic can not be closed for the tunnel that passes through the dense buildings and politically sensitive areas of the city, It is feasible to adopt double-layer tunneling structure. Due to the influence of ground traffic, the tunnel itself has a large span of excavation, small buried depth and poor geological conditions, the ground loss caused by tunnel excavation may cause ground subsidence or even topping. Therefore, it is necessary to take strong advance support measures before tunnel excavation. The use of advanced pipe curtain method can minimize land subsidence and reduce the influence of ground traffic on tunnel excavation. It can be popularized and combined with freezing method and grouting in the hole, which can guarantee the safety during construction. At the same time, the problems that need further research are also pointed out. The numerical analysis is based on the design and construction, which can basically reflect the dynamics of the tunnel in the construction process, and can provide a reference for the design and construction of similar tunnel engineering.
【學(xué)位授予單位】：武漢工程大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2014
【分類號】：U455

【參考文獻(xiàn)】

相關(guān)期刊論文 前5條

1 師金鋒,張應(yīng)龍;超大斷面隧道圍巖的穩(wěn)定性分析[J];地下空間與工程學(xué)報;2005年02期

2 雷震宇,郭慶海,周順華;大跨度淺埋暗挖隧道拆撐的數(shù)值模擬[J];地下空間與工程學(xué)報;2005年02期

3 陳小良;劉元雪;李忠友;;雙層隧道中隔板的位置優(yōu)化[J];地下空間與工程學(xué)報;2010年S2期

4 牛澤林;李德武;;黃土地區(qū)單洞雙層公路隧道有限元分析與研究[J];公路;2007年11期

5 張程紅;李德武;李慎奎;齊美娟;;軟巖雙層隧道的力學(xué)性能分析[J];四川建筑;2009年01期

相關(guān)博士學(xué)位論文 前1條

1 萬明富;超大跨公路隧道開挖力學(xué)行為研究[D];東北大學(xué)　;2009年

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