考虑非饱和渗流的谷幅变形对高拱坝影响分析  

Analysis of the influence of valley width deformation on high arch dam considering unsaturated seepage

作　　者：辛长虹 赵引[1] XIN Changhong;ZHAO Yin(College of Mechanics and Materials,Hohai University,Nanjing 210098,China)

机构地区：[1]河海大学力学与材料学院,江苏南京210098

出　　处：《水利水运工程学报》2021年第4期36-45,共10页Hydro-Science and Engineering

基　　金：国家自然科学基金资助项目(51739006)。

摘　　要：蓄水初期谷幅变形对拱坝当前工作性态和长期安全状况的影响是坝工界和学术界面临的新课题。针对我国锦屏一级拱坝蓄水期间出现的谷幅收缩问题,基于非饱和渗流分析理论,采用非线性有限元数值分析方法,通过对裂隙岩体吸湿曲线进行敏感性分析,研究了非饱和渗流过程中的谷幅变形规律,并分析了谷幅变形对大坝位移和应力的影响。结果表明:在非饱和渗流场作用下,两岸边坡向河谷中心变形,且上游比下游的谷幅变形值大。随着水位的升高,谷幅变形值不断增大,当渗流场达到饱和时谷幅收缩值最大。在非饱和渗流过程中坝体位移和应力的分布规律基本保持不变,但随水位的升高坝体最大顺河向位移和最大主压应力略有减小,最大主拉应力略有增加。谷幅收缩对坝体产生挤压作用,导致坝体最大顺河向位移减小,最大主拉应力由坝踵向坝肩上游侧转移,下游面高压应力区向拱冠梁中部扩展,且饱和渗流场对拱坝位移和应力的影响比非饱和渗流场明显,但渗流场作用的谷幅变形对坝体位移和应力的改变有限,不会影响坝体的整体稳定性。The effect of valley width deformation during the initial impoundment stage on the subsequent working behavior and the long-term safety of an arch dam has become an increasingly important chanllenge faced by dam engineering and academia.This study aims to analyze the sensitivity of valley width deformation to the absorption curve of fractured rock mass to address the challenge of valley width reduction during impoundment of the JinpingⅠarch dam in China.The methods of unsaturated seepage analysis theory and nonlinear finite element numerical analysis were applied to study the law of valley width deformation during unsaturated seepage process.The influence of valley width deformation on the displacement and stress of the dam was analyzed.The results showed that the slope on both sides of the valley deformed towards the center under the action of the unsaturated seepage field.The deformation of valley width upstream exceeded that downstream.The valley width deformation increased with an increasing elevation of the water level,and maximum valley width reduction occurred in the saturated seepage field.The distribution of displacement and stress of the dam changed little during the unsaturated seepage process.However,the maximum longitudinal displacement and the minor principal stress of the dam decreased gradually with increaseing elevation of the water level.There was a gradul increase in the major principal stress.The valley width reduction had a squeezing effect on the dam body,resulting in a decrease in the maximum longitudinal displacement,the transfer of the major principal tensile stress from the dam heel to the upstream side of the dam abutment,and the extension of the highpressure stress zone on the downstream surface to the middle of the crown cantilever.The influence of the saturated seepage field on the displacement and stress of the dam was more obvious than that of the unsaturated seepage field.However,the valley width deformation resulting from the seepage field had a limited effect on the displaceme

关 键 词：非饱和渗流 吸湿曲线 谷幅变形 特高拱坝 

分 类 号：TV311[水利工程—水工结构工程]