基于地质力学模型试验的拱坝整体稳定性分析  

Global Stability Analysis of Arch Dam based on Geomechanical Model Test

作　　者：朱涛[1] 刘耀儒[2] 庄文宇 于海江[1] 王兴旺 ZHU Tao;LIU Yaoru;ZHUANG Wenyu;YU Haijiang;WANG Xingwang(China Water Resources Beifang Investigation,Design and Research Corporation Limited,Tianjin 300222,China;State Key Laboratory of Hydroscience and Engineering,Tsinghua University,Beijing 100084,China)

机构地区：[1]中水北方勘测设计研究有限责任公司,天津300222 [2]清华大学水沙科学与水利水电工程国家重点实验室,北京100084

出　　处：《西北水电》2022年第6期111-119,126,共10页Northwest Hydropower

基　　金：国家自然科学基金(41961134032;51739006)。

摘　　要：地质力学模型试验是评价拱坝整体稳定性和加固处理效果的有效手段,采用200∶1几何比尺对新疆某高拱坝进行三维地质力学模型试验;模型采用小块体砌筑技术对坝址区不同质量分级岩体的变形、强度特性以及优势节理裂隙进行模拟,基于压缩变形相等的原则模拟断层、岩脉等软弱结构面,并且考虑了建基面槽挖填换混凝土、抗剪洞等加固处理措施;基于油压千斤顶加载系统模拟坝面分布式水载,采用数据采集系统和视频监控系统记录分析坝体及坝基在超载过程中的变形、应力和开裂破坏过程;确立了拱坝起裂安全度K_(1)、非线性起始安全度K_(2)、极限荷载安全度K_(3)三个稳定性评价指标;此外建立数值模型,基于变形加固理论对比分析了拱坝的整体稳定性,确定工程稳定的控制部位和值得注意的薄弱区域。结果表明:拱坝的3个安全度分别为K_(1)=2.0、K_(2)=4.5~6.0、K_(3)=11~12。在超载过程中,河床右岸坝踵破坏程度较左岸严重,断层jef36、jef4局部出现开裂但未见明显错动。整体而言,地基和坝体的破坏程度均较小,整体上是稳定的。The geomechanical model test is an effective means to evaluate the global stability of the arch dam and the effect of reinforcement.The three-dimensional geomechanical model test of an arch dam is carried out with a geometric scale of 200∶1.The model adopts small block masonry technique to simulate the deformation,strength characteristics and dominant joint fissures of rock masses with different quality grades at the dam site.Based on the principle of equal compression deformation,the model simulated the weak structural planes such as faults and dykes,and considered the reinforcement measures such as concrete replacement and anti-shear tunnel.Based on the hydraulic jack loading system,the distributed water load on the dam surface is simulated.The deformation,stress and cracking process of the dam and foundation in the process of overload are recorded and analyzed by the data acquisition system and the video monitoring system.Three stability evaluation indexes of dam,i.e.crack initiation safety degree K_(1),nonlinear initial safety degree K_(2)and ultimate load safety degree K_(3),are proposed.In addition,a numerical model is established.Based on the deformation reinforcement theory,the global stability of arch dam is compared and analyzed,and the control areas for the project stability and the weak areas worthy of attention are determined.The results show that K_(1)=2.0,K_(2)=4.5~6.0,K_(3)=11~12.In the process of overloading,the dam heel on the right bank is more severely damaged than that on the left bank.The faults jef36 and jef4 are cracked locally but no obvious dislocation is found.The damage degree of the foundation and dam is small,and the dam is stable on the whole.

关 键 词：地质力学模型试验 整体稳定性 拱坝 小块体砌筑技术 变形加固 

分 类 号：TV698.11[水利工程—水利水电工程] TV642.42