【作者】 胡军；

【导师】 李俊杰；

【作者基本信息】 大连理工大学 ， 防灾减灾及防护工程， 2008， 博士

【摘要】 高土石坝的抗震稳定分析是关系坝体安全的关键要素,以往的研究表明,土石坝遭遇强震而发生破坏时,破坏将首先从坝顶部开始,坝顶区的“鞭鞘”效应将使堆石处于不稳定状态,因此在高烈度区修建高土石坝应特别重视坝顶的稳定,采取必要的抗震加固措施。锚杆、锚索、土钉、框架格构梁近年来被广泛地应用于边坡加固工程中,由于加固构件与土体之间的接触面力学性质比较复杂,这些加固构件与土体的相互作用机理研究滞后于工程应用,因此加强设计理论研究,制定相应的规范,是一项重要的工作。结合国家电力公司科学技术项目（专题四:心墙堆石坝动力反应分析计算理论及抗震措施研究,合同编号:SP11-2002-03-50）开展了如下的研究工作:（1）FLAC^3D自带较多的本构模型,但是国内岩土工程界广泛采用的南水模型并没有包含在FLAC^3D中,这使得FLAC^3D在国内岩土工程数值分析中,尤其是在土石坝的数值分析中的应用受到了很大局限。为了弥补这一不足,利用FLAC^3D提供的二次开发平台,实现了南水模型在FLAC^3D软件中的应用。（2）对糯扎渡粘土心墙坝采用开发的南水模型进行静力计算,在此基础上进行动力反应分析,计算结果表明:在地震情况下,坝顶的加速度较大,最大加速度值为7.9 m╱s²,永久位移达到1.1m,土石坝的宏观破坏性态表现为坝顶沿坝坡浅层较大变形,需要采取局部加固措施以增强坝体的抗震稳定性。（3）在现有变分法求解边坡稳定的基础上,推导了一种能适用于非均质边坡的稳定分析方法。该方法没有对条间力做任何假定,它利用变分原理求解安全系数的泛函,进而确定极限平衡方程中的未知函数——滑裂面上的正应力和滑裂面。然后通过求解极限平衡方程,得到目标函数的极值——最小安全系数。依据推导过程,编制了三维变分法计算程序。该程序可以搜索边坡破坏的临界滑裂面,而且能够得到与其对应的最小安全系数。（4）采用有限差分法,对坝体及其抗震措施进行数值模拟,通过对加筋前后坝体永久位移的计算分析,研究了筋端处理方式、加筋的间距、锚筋长度、预应力大小、筋材的剪切抗力等因素对加固效果的影响。同时进一步考虑了锚筋的剪切抗力对边坡稳定有着不可忽视的贡献,提出了一种考虑锚筋单元剪切抗力的计算方法,并通过对工程实例的计算,说明锚筋单元剪切抗力对提高边坡稳定的作用。（5）以往的测试结果表明,土工格栅的抗拉拔能力远远超过钢带和土工织物,根据土工格栅的作用原理以及坝体动力和稳定分析结果,将混凝土框架格构梁平铺于坝体中坝高的3/4以上部分,研究了混凝土框格与土体的相互作用,提出了一种简便的混凝土框格计算模型。更多还原

【Abstract】 The analysis of the stability of high earth-rockfill dam under earthquake is important to the safety of dam. Previous research indicates that upper part is failed firstly when earth-rockfill dam is damaged under strongly earthquake loading, rockfill in upper part is unstable because of whiplash effect. So it is necessary to take earthquake-resistant measures to high earth-rockfill dam. Cable, soil nail, geogrid, etc. are widely used in stabilizing structure of slope reinforcement. However the mechanical character of contact surface between reinforced components and soil mass is complicated, studies on theory of these structure are delayed greatly than their applications. For theses reasons, it is pressing and significant to strengthen theorictical study and set design criterion. The work in this thesis is supported by the science and technology project of National Power Company（Study on calculation theory dynamic response and earthquake-resistant measures of Nuozhadu core rock-fill dam. No. SP11-2002-03-50） and relative horizontal projects. The main aehievements and highlights of the dissertation are asfollows:（1）There are several built-in materal models in FLAC^3D. But the nanshui model, which is widely used in the geotechnical engineering field, is not included in it. Which limit the application of FLAC^3D greatly. In order to fetch up this shortage, Utilizing the further developing platform, the Nanshui constitutive model is developed in FLAC^3D with Visual Studio 2005 environment.（2） Dynamic analysis is done to Nuozhadu rockfill dam, based on the static analysis using Nanshui model developed in FLAC^3D. Results show that, the maximum acceleration appears in the top of the dam and the maximum value is 7.9 m/s², the permanent displacement is 1.1 m. The macro breakage property behaves as the top area of the dam slides along the shallow area of the slope. To strengthen the stability of the dam, it is necessary toresort to some relevant reinforcement measures.（3） A new slope stability analysis method, explicitly satisfying all limiting-equilibriumequations is presented. To make the problem statically determinate variational approach is used. In this approach, the normal stress and the critical slip are got by solving the Euler’s equations. The minimum factor of safety for the critical surface is sought and obtained mathematically. A simple numerical routine, which can attain the safety factor for anisotropic soil slope is compiled. The critical slip surface can be automatically drawn by computer.（4） Through the numerical simulation of the reinforced dam by finite difference method, factors which might have effect on reinforcing effect are discussed, such as anchorage mode, cable space, cable length, prestress. At the same time, A new function is proposed for evaluating shear force in cables. Through the calculation of nuozhadu rockfill dam, result shows us the shear force of cable place an important role in mainting stability of slope.（5）According to the previous research, pulling out resistance of geogrid is superior to that of steel bar. Based on geogrid reinforcement theory, concrete framed beams are laid in 3/4 height upwards of earth-rockfill dam, Taking into account for the interaction between concrete frame and soil, a simple model of frame beam is put forwarded.更多还原