水下浅埋暗挖隧道的覆盖层安全厚度研究及开挖工序模拟

【作者】 张聚文；

【导师】 傅鹤林； 伍毅敏；

【作者基本信息】 中南大学 ， 桥梁与隧道工程， 2010， 硕士

【摘要】 随着我国建设的蓬勃发展,涌现了各种过江跨海隧道,而水下隧道的建设将直接面临选取隧道覆盖层安全厚度的问题。据以往经验,合理的隧道覆盖层安全厚度既是水下隧道建设的一个重要经济指标,又是控制水下隧道施工和运营安全的一个重要因素。由于岩土体通常都含有节理裂隙、破碎带等软弱夹层,并且水下隧道不可避免遇到渗流场与应力场相互作用的耦合问题,再加上水下隧道的地质环境复杂且难以探明,从而使得水下隧道施工具有高难度和高风险性。然而我国水下隧道的出现和研究较晚,水下隧道覆盖层安全厚度的系统研究较少,目前还没有明确的规范,仍处于探索研究阶段。因此,水下隧道覆盖层安全厚度的确定将日益成为目前隧道工程建设中的亟待解决的难题。为此本文以长沙市湘江大道浏阳河水下隧道为依托,结合国家自然科学基金(50878213)、长沙市科技计划项目(K0902027-11),主要开展如下工作：(1)比较借鉴国内外已建水下隧道的成功经验,总结确定水下隧道安全覆盖层厚度的主要经验方法,并结合浏阳河隧道实际工程情况,工程类比分析确定合理隧道安全覆盖层厚度的范围。(2)结合断裂损伤与流固耦合的基本理论,探讨了断裂损伤与流固耦合理论在有限三维差分程序FLAC3D中的运用。(3)基于己探明的隧道场地条件,并考虑围岩节理裂隙的断裂损伤效应,对浏阳河水下隧道动态施工过程进行数值模拟分析,研究不同工况下围岩和支护结构中应力场特征及其位移变化规律,对比分析得到节理裂隙的影响系数,并推出了经验修正公式。(4)采用FLAC3D数值方法,并考虑流固耦合效应,对静水平面17m下的隧道施工进行数值模拟分析,再结合日本最小涌水量法进行渗流分析研究,对隧道覆盖层厚度进行定性分析。更多还原

【Abstract】 With the vigorous development of the Chinese construction, it springs up various river-crossing or cross-sea tunnel. And subaqueous tunnel construction will directly face selection for the safe thickness of roof at first. According to the previous experience, reasonable safe thickness of tunnel roof is not only an important economic indicator for underwater tunnel construction, but also an important factor of safety for underwater tunnel construction and operation. As the rock mass usually contains soft interlayer such as joints, crack, fault fracture zone and so on, and underwater tunnel inevitably encounter the coupling interaction between the seepage field and stress field, and because the geologic environment around subaqueous tunnel is complex and difficult to proven, thus the underwater tunnel construction is difficult and high risk. However, the research of underwater tunnel in China initiated relatively late, the systematic study on the least security coping thickness for an underwater tunnel are less, and there is no clear specification, it is still at the exploratory research stage at present. So the determination of the coping thickness for an underwater tunnel is urgently needed to be settled for current tunnel construction building. Therefore, relying on Liuyang River Underwater Tunnel of Xiang River Road in Changsha City, National Natural Science Foundation(50878213), and Changsha Science and Technology Project(K0902027-11), the disseration presents a numerical simulation study as the following:1. compare with and refer to international main experience, summarized the main empirical method, based on practical engineering of Liuyang River Underwater Tunnel, determined the reasonable security coping thickness for underwater tunnel by engineering analogy analysis.2. Combined the basic theory of fracture damage with fluid-solid coupling, the theory is applied in the three-dimensional differential procedure FLAC3D.3. Based on the proved tunnel site conditions, and consider fracture damage of joint fissure, numerical simulation analysis is made of the dynamic construction process in Liuyang River Underwater Tunnel, study on the stress and displacement variation characteristics of surrounding rock and supporting structure in different conditions, obtained influence coefficients of joint fissure by comparative analysis, and deduce the experience correction formulae.4. By FLAC3D numerical methods, and consider the fluid-structure coupling effect, the numerical simulation analysis for the tunnel construction at horizontal 17m below, combined with Japan’s minimum water yield to research for seepage calculation, analyze tunnel coping thickness qualitatively.更多还原