【作者】 朱亚林；

【导师】 孔宪京；

【作者基本信息】 大连理工大学 ， 岩土工程， 2011， 博士

【摘要】 高土石坝抗震研究的重点和目标,主要是根据结构的破坏特征以及工程的破坏机理来提出合理的抗震设计方法和抗震措施,同时研究相应抗震措施的作用机理,从而达到解除地震灾害之虞。本论文结合国家自然科学基金项目《强震区高土石坝抗震措施研究》(50679093)和国家自然科学基金重大研究计划重点项目《高土石坝地震灾变模拟及安全控制方法研究》(90815024),通过程序二次开发,发展了FLAC非线性弹塑性分析方法,研究了高土石坝的动力反应特性和破坏机理,同时对振动台试验进行数值模拟并与试验结果对比分析,研究了土工格栅抗震加固措施的效果及影响因素,最后通过工程实例进行验证,论文的主要内容如下：(1)发展了高土石坝的动力弹塑性分析方法,与有限元结果相比较,验证了FLAC程序模拟高土石坝地震反应的合理性。对高土石坝的地震反应特性和破坏机理进行了系统研究,主要研究了地震动作用下坝体的剪应变、永久位移以及网格变形的变化规律,同时分析了坝高、坝坡和地震动峰值参数变化对大坝破坏性态的影响。(2)在二维分析的基础上,应用三维非线性动力弹塑性分析方法,研究了狭窄河谷中高土石坝的动力反应特性,通过计算分析,给出了不同河谷形状系数下高土石坝的剪应变和永久位移分布规律。(3)在土石坝坝坡模型振动台破坏试验基础上,采用数值分析方法,对坝坡的动力特性、稳定性以及加筋抗震措施的性能进行研究。采用动力弹塑性分析方法,对坝坡模型振动台试验进行数值仿真,通过类比计算工况,比较、分析了坝坡的破坏过程及其破坏性态,以及永久位移的变化规律；同时采用拟静力方法对坝坡的稳定性进行分析,通过设定滑裂面参数,比较滑裂面的深浅,分析了加筋对坝坡稳定性的影响,并与试验结果进行对比验证。(4)在高土石坝动力反应特性的基础上,建立了土工格栅加筋高土石坝的弹塑性分析模型,并利用该模型对土工格栅加筋高土石坝的受力情况、变形和破坏机理进行研究,分析了土工格栅的连接方式、长度、刚度以及铺设间距等参数对高土石坝变形的影响。(5)通过对两河口高心墙坝进行实例分析,研究了大坝的动力反应和永久变形并与已知数值的比较,研究了加筋抗震措施的效果,从稳定和变形的角度初步分析了高土石坝抗震加固后的极限抗震能力。更多还原

【Abstract】 Reasonable seismic design methods and aseismic measures should be proposed according to the characteristic of damages and failure mechanism of structures, and anti-seismic mechanism of the corresponding measures should be studied, which are the key problems and aims in aseismic research on high earth-rockfill dam. The research is supported by the National Science Foundation of China "Study on Aseismic Meassures of High Earth-rockfill Dam in Strong Earthquake Zone" (No.50679093) and the Mega-project of Natural Science Foundation Program "Research on Earthquake Disaster Simulation and Safety Control Method of High Earth-rockfill Dam" (No.90815024). In this paper, the nonlinear elastoplastic analysis method of FLAC was used and the dynamic response characteristics and failure mechanism of high dam were studied firstly. Secondly, the numerical simulation was used and good agreements were obtained between the numerical results and those from shaking table tests. Thirdly, the effect of seismic of geogrid reinforcement measures was analysed. And finally an engineering example was verified using numerical simulation. The main contents of the current research are as follows:(1) The main purpose is to study the seismic response and failure mechanism of high earth-rockfill dams under earthquakes by using dynamic elasto-plastic methods. The results of the FEM verify the reasonableness of FLAC procedures in simulating the seismic response of high earth-rockfill dams. The main concerned aspects are the shear strain, the permanent deformation as well as the grid deformation during earthquakes. At the same time, the influences of parameters as dam height, slope and ground motion on failure modes of dams are systematically studied.(2) Based on two-dimensional analysis, the main purpose is to study the seismic response of high earth-rockfill dam in narrow valley by the method of three-dimensional nonlinear dynamic elasto-plastic analysis method. The distributions of shear strain and permanent deformation of different valleys of the dam are provided.(3) The seismic response, stability and reinforced the aseismic measures of earth-rockfill dam was studied based on shaking table test and numerical simulation. An elastic-plastic analysis method was applied to simulate and analyze the dynamic failure process and permanent deformation of earth-rockfill dam slope under seismic motion. At the same time, the stability of slope, the depth of slip surface and the effectiveness of reinforcement were investigated by the method of quasi-static. The calculated results and those obtained from shaking table tests are compared.(4) Based on the dynamic response of high earth-rockfill dam, a dynamic elasto-plastic analysis method for the high earth-rockfill dam slope reinforced with geogrids was set up. Based on this model, the behavior, deformation and failure mechanism of such a high earth-rockfilled dam slope, as well as the geogrid connection, the length, the spacing and the stiffness on the deformation of the high earth-rockfill dam are analyzed.(5) The Lianghekou high core rock-fill dam was taken as an example. The dynamic response of the dam and permanent deformation is analyzed and compared with the known values. At the same time, the effects of aseismic reinforcement measures are studied. And the maximum aseismic capability of dam is preliminarily evaluated from the stability and deformation after reinforcement.更多还原