【作者】 于跃；

【导师】 钟登华；

【作者基本信息】 天津大学 ， 水工结构工程， 2010， 博士

【摘要】 观音岩水电站坝址工程地质条件复杂,坝基为软硬相间的层状地层岩体,且局部区域有岩溶现象发育。在这样复杂的地基条件下,修建高达160m级的碾压混凝土重力坝,准确认识与把握复杂岩体特性,通过进行科学的计算与分析,提出切实可行的基础处理方案,是确保整个工程安全的必要条件。本文针对观音岩水电工程复杂的地质条件,基于所建立的三维地质分析模型,充分考虑坝基存在软硬相间、有岩溶发育等多种结构面组合的岩体特性,重点研究了各种工况下坝体、坝基的应力变形特性。考虑到岩溶发育的不确定性,采用随机有限元仿真分析方法,研究了溶蚀区域在坝址基岩部位分布对大坝安全性的影响。在对提出的坝基处理方案进行计算、分析与评价基础上,提出了较优的地基处理方案。论文主要研究内容及成果如下:(1)充分考虑包括岩溶发育在内的复杂坝基地质条件,建立了工程三维地质分析模型并进行精细的可视化分析研究。在此基础上,采用数值模拟的方法建立三维整体地质的有限元模型,可完全模拟坝基岩层软硬相间、有岩溶发育及多种结构面组合的坝基岩体特性。(2)运用有限元结构数值仿真分析方法,研究复杂层状坝基基岩条件下,特别是溶蚀区域存在时坝体、坝基的静、动力特性,并对坝基基岩内有无溶蚀区域分布的不同计算结果进行比较。(3)在考虑实体模拟溶蚀分布对坝体影响分析基础上,加入了溶蚀区域材料参数随机和溶蚀区域位置随机两种方法,进行了溶蚀区域在坝址基岩部位分布对典型坝段安全性影响的有限元分析研究工作。(4)基于随机场理论建立整个坝址区溶蚀分布整体随机场,并选取典型坝段,建立典型坝段溶孔分布频率随高程变化的若干种回归模型。确定最优的回归模型并根据该模型随机抽取若干方案进行有限元计算,得到多方案下坝体应力、应变结果,对典型坝段进行安全性评价。(5)基于三维地质分析模型,提出了多种地基处理方式,并进行三维非线性有限元敏感性分析,基于计算结果对这些地基处理方式进行评价,提出较优的地基处理方案,为工程设计提供参考。更多还原

【Abstract】 The engineering geological conditions of the dam foundation of Guan Yinyan hydropower project are quite complex. The dam foundations are consisted of soft and hard layered rock masses alternately distributed where occasionally exist corrosion phenomenons in some area. To build a RCC gravity dam with a height of nearly 160m under such complex foundation condition, it is quite necessary to recognize the characteristics of the complicated rock masses and provide feasible foundation treatment scheme according to scientific calculation and analysis to ensure the project safty.In this paper, aiming at the complex engineering geological condition of Guan Yinyan hydropower project, a 3D geological analysis models are established which expressed integrated geological information of the dam foundation including alternately distributed soft and hard layered rock masses and occasionally existed corrosion. The stress and deformation characteristics of the dam and its foundation under different calculation conditions have been mainly studied. Considering the uncertainty of karst development, the influence of regional distribution of corrosion on dam safety is researched using the SFEM simulation analysis method. The optimal dam foundation treatment measure is proposed according to computing, analyzing and evaluating these proposed dam foundation treatment measures.The main research contents and achievements are as follows:(1) 3D geological analysis models of Guan Yinyan hydropower project are established considering soft and hard layered rock masses alternately distributed where occasionally exist corrosion phenomenons in some area. The refined 3D visualization analysis research is carried out through the 3D geological analysis models. The finite element model of the whole 3D geological models, which can completely simulate dam foundation rock mass characteristics of soft and hard layered rock masses alternately distributed, corrosion development and various structure surface combination, is set up adopting numerical simulation method.(2) By applying the finite element structure numerical simulation analysis method, static and dynamic characteristics of dam body and foundation is reasearched under the complex layered bedrock condition where occasionally exist corrosion phenomenons in some area. The computation results with or withnot corrosion region in dam foundation are compared and analyzed. (3) Based on analyzing the influence of corrosion distribution on dam body using entity simulation method, considering the material randomicity and position randomicity of corrosion region, the influence of regional distribution of corrosion on safety of the typical dam section is researched using the FEM simulation analysis method.(4) The whole random field of corrosion distribution in dam site region is established based on the random field theory. And several regression models, which reflect the distribution frequency of dissolution pore with the elevation change, are built through choosing the type dam section. The best regression model can be confirmed and some schemes can be obtained. By computing using the FEM, the stress and strain results of multiple schemes are acquired, which can be used to estimate the security of the typical dam section.(5) Several foundation treatment schemes are proposed based on 3D geological analysis model. These schemes are compared and evaluated through 3D nonlinear finite element sensitivity analysis. The optimal dam foundation treatment measure is confirmed, which can provide some references to engineering design.更多还原