五嘎冲拱坝坝肩加固效果分析及整体安全度评价
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摘要
五嘎冲拱坝右岸坝肩由于存在张性裂隙、软弱层以及泥化夹层等地质缺陷,坝肩抗滑稳定不能满足要求而采取加固措施。根据工程最新揭示的地质资料、拱坝结构设计成果以及加固处理措施,建立拱坝–地基整体三维数值模型。采用满足Mohr-Coulomb屈服准则的节理单元,模拟基岩中张性裂隙、软弱夹层、层间泥化夹层等构造。采用非线性有限元法,对加固前后坝基岩体及结构面的变形、屈服区进行对比分析,评价右岸坝肩加固处理措施的有效性,采用水容重超载法分析拱坝坝体和地基岩体的变形以及屈服状态的发展过程,给出加固处理后拱坝–地基系统的整体安全度,结合工程类比,综合评价五嘎冲拱坝的整体安全性。计算成果表明,针对右岸L1张性裂隙所进行的加固处理措施可明显提高右岸坝肩的稳定性,加固效果显著,五嘎冲拱坝坝肩加固处理后超载安全度较高,处于高坝工程的偏上位置。
Since there exist some geological defects such as extensional fractures, weak layers and clay interactions in the right dam abutment of Wugachong Arch Dam, the dam abutment anti-sliding stability cannot meet the safety requirements, thus some reinforcement measures need to be taken. According to the Wugachong Arch Dam's latest geologic data and the arch dam structure design results, a 3D numerical model for the whole arch dam is built. The joint elements for Mohr-Coulomb yield criterion are adopted to simulate the structure of the foundation's extensional fractures, weak layers and clay interactions. Using the nonlinear finite element method, the deformation and yield region of foundation rock and structural surfaces before and after reinforcement are compared; the effectiveness of the reinforcement measures to the right bank abutment is evaluated. The deformation and yield condition's development of arch dam and foundation rock is analyzed by using water density overload method. And the global safety of arch dam-foundation system after reinforcement is given. By comparison with similar engineering, the Wugachong Arch Dam's global safety is evaluated comprehensively. The results show that the reinforcement measures to the extensional fracture L1 can improve on the right bank abutment stability obviously. After reinforcement, Wugachong Arch Dam's abutment has high overload safety which is superior among the high dams.
Since there exist some geological defects such as extensional fractures, weak layers and clay interactions in the right dam abutment of Wugachong Arch Dam, the dam abutment anti-sliding stability cannot meet the safety requirements, thus some reinforcement measures need to be taken. According to the Wugachong Arch Dam's latest geologic data and the arch dam structure design results, a 3D numerical model for the whole arch dam is built. The joint elements for Mohr-Coulomb yield criterion are adopted to simulate the structure of the foundation's extensional fractures, weak layers and clay interactions. Using the nonlinear finite element method, the deformation and yield region of foundation rock and structural surfaces before and after reinforcement are compared; the effectiveness of the reinforcement measures to the right bank abutment is evaluated. The deformation and yield condition's development of arch dam and foundation rock is analyzed by using water density overload method. And the global safety of arch dam-foundation system after reinforcement is given. By comparison with similar engineering, the Wugachong Arch Dam's global safety is evaluated comprehensively. The results show that the reinforcement measures to the extensional fracture L1 can improve on the right bank abutment stability obviously. After reinforcement, Wugachong Arch Dam's abutment has high overload safety which is superior among the high dams.
引文
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[3]张磊,张国新.SAPTIS:结构多场仿真与非线性分析软件开发及应用(之三)[J].水利水电技术,2014,45(1):52-55.ZHANG Lei,ZHANG Guo-xin.Development and application of SAPTIS——A software of multi-field simulation and nonlinear analysis of complex structures(part III)[J].Water Resources and Hydropower Engineering,2014,45(1):52-55.
[4]张国新,沙莎.混凝土坝全过程多场耦合仿真分析[J].水利水电技术,2015,46(6):87-93.ZHANG Guo-xin,Sha sha.The multi-field coupling simulation analysis of concrete dams during the whole process[J].Water Resources and Hydropower Engineering,2015,46(6):87-93.
[5]SHI G H.Block System modeling by discontinuous deformation analysis[M].U.S.A:Computational Mechanics Publications,1993.
[6]张国新,李海枫,黄涛.三维不连续变形分析理论及其在岩质边坡工程中的应用[J].岩石力学与工程学报,2010,29(10):2116-2125.ZHANG Guo-xin,LI Hai-feng,HUANG Tao.Threedimensional discontinuous deformation analysis theory and its application to rock slopes[J].Chinese Journal of Rock Mechanics and Engineering,2010,29(10):2116-2125.
[7]周少怀,杨家岭.DDA数值方法及工程应用研究[J].岩土力学,2000,21(2):123-125.ZHOU Shao-huai,YANG Jia-ling.DDA method and its application to engineering[J].Rock and Soil Mechanics,2000,21(2):123-125.
[8]宁宇,徐卫亚,郑文棠,等.白鹤滩水电站拱坝及坝肩加固效果分析及整体安全度评价[J].岩石力学与工程学报,2008,27(9):1890-1898.NING Yu,XU Wei-ya,ZHENG Wen-tang,et al.Reinforcement effect analysis and global safety evaluation of arch dam and abutment of Baihetan Hydropower Station[J].Chinese Journal of Rock Mechanics and Engineering,2008,27(9):1890-1898.
[9]余天堂,任青文.锦屏高拱坝整体安全度评估[J].岩石力学与工程学报,2007,26(4):788-794.YU Tian-tang,REN Qing-wen.Evaluation of global safety degree of Jinping high arch dam[J].Chinese Journal of Rock Mechanics and Engineering,2007,26(4):788-794.
[10]李同春,王仁坤,游启升,等.高拱坝安全度评价方法研究[J].水利学报,2007,38(增刊):78-83,105.LI Tong-chun,WANG Ren-kun,YOU Qi-sheng,et al.Study on safety evaluation methods for high arch dams[J].Journal of Hydraulic Engineering,2007,38(Supp.):78-83,105.
[11]王仁坤,林鹏,周维垣.复杂地基上高拱坝开裂与稳定研究[J].岩石力学与工程学报,2007,26(10):1951-1958.WANG Ren-kun,LIN Peng,ZHOU Wei-yuan.Study on cracking and stability problems of high arch dams on complicated foundation[J].Chinese Journal of Rock Mechanics and Engineering,2007,26(10):1951-1958.