堰塞体状态相关剪胀理论与坝体溃决演化规律研究构想  

Research Framework of the State-dependent Dilatancy Theory and Breach Evolution Law of Landslide Dam

作　　者：蔡正银[1,2] 钟启明 何宁[1,2] 夏云峰 朱俊高[4] CAI Zhengyin;ZHONG Qiming;HE Ning;XIA Yunfeng;ZHU Jungao(Geotechnical Eng.Dept.,Nanjing Hydraulic Research Inst.,Nanjing 210024,China;MWR Key Lab.of Reservoir Dam Safety,Nanjing 210029,China;River Harbor Eng.Dept.,Nanjing Hydraulic Research Inst.,Nanjing 210024,China;College of Civil and Transportation Eng.,Hohai Univ.,Nanjing 210098,China)

机构地区：[1]南京水利科学研究院岩土工程研究所,江苏南京210024 [2]水利部水库大坝安全重点实验室,江苏南京210029 [3]南京水利科学研究院河流海岸研究所,江苏南京210024 [4]河海大学土木与交通学院,江苏南京210098

出　　处：《工程科学与技术》2021年第6期21-32,共12页Advanced Engineering Sciences

基　　金：长江水科学研究联合基金重点支持项目(U2040221)。

摘　　要：堰塞体一般在自然力作用下瞬间形成,堆积体具有空间结构复杂、坝料级配宽泛、稳定性差、易在水流冲刷下发生溃决等特点。堰塞体作为一种重大的水旱自然灾害,其安全评价和灾害预测是国内外学者关注的焦点,目前尚有很多问题需要解决,包括:1)堆积体由天然宽级配土石料构成,表现出显著的状态相关性,缺乏正确描述这种宽级配堆石料状态的相关剪胀理论与本构模型;2)堰塞体形成后,会受上游堰塞湖水位抬升、持续非稳定渗流、湖区滑坡涌浪、后期地震等外荷载作用的影响,缺乏稳定性评判的标准和方法;3)堰塞体缺乏必要的洪水溢流设施,容易发生溃决,且溃决水流冲蚀过程呈明显的非线性特点,溃口水力要素指标呈强非恒定流特征,缺乏反映宽级配堰塞体材料冲蚀机理的溃决过程数学模型。为此,有必要采取现场勘查、多尺度物理模型试验、数值仿真等综合手段开展研究,揭示堰塞体外观形态、内部结构和材料宏观力学特性及其时空变异规律,提出状态相关(级配、孔隙比、应力水平)的宽级配堰塞体材料剪胀方程,建立能适应复杂应力路径的广义弹塑性本构模型与坝体极限平衡分析方法;开展大型水工模型试验和溃坝离心模型试验研究,揭示非恒定流作用下堰塞体材料的动态冲蚀特性与堰塞体溃口演化规律,建立非恒定流作用时溃口动边界条件下的挟砂水流冲蚀方程,提出考虑流固耦合的堰塞体溃决过程数学模型,实现堰塞体漫顶或渗透破坏溃坝全过程水流运动特征、坝料输移规律、溃口演化过程及结构失稳的数值模拟;综合可靠度理论与溃坝过程数值模拟方法,提出能考虑流固耦合的堰塞体渗流、变形、稳定和溃决过程的一体化数值仿真平台,构建堰塞体全生命周期安全评价与灾变模拟理论体系与方法,为提升中国堰塞体防灾减灾决策水平提供科�Landslide dams are usually formed instantaneously by natural forces,the accumulation bodies have the characteristics of complex space structure,wide gradation of dam materials,poor dam stability,and they are easy to fail under the flow erosion.As a major natural disaster of flood and drought,safety evaluation and disaster prediction of landslide dams have been the focus of attention by the scholars around the world,but many questions remain unanswered,which are mainly manifested in:1)Accumulation bodies are composed of natural wide-graded rockfill materials with significant state-dependent correlation,there is a lack of the state-dependent dilatancy theory and constitutive model of wide-graded rockfill materials.2)After the formation of landslide dams,they would be affected by external loads,such as the rise of upstream water level of dammed lake,continuous unsteady seepage,landslide surge in the dammed lake,and earthquake,there is also a lack of standards and methods for stability evaluation.3)Due to the lack of necessary flood relief facilities,the landslide dams are prone to fail;under the action of outburst flow,obvious nonlinear characteristics are manifested during the breach development,as well as strong unsteady flow characteristics of the hydraulic elements;there is a lack of numerical models for landslide dam breaching which can reflect the erosion mechanisms of wide graded materials.Therefore,it is necessary to conduct integrated scientific measures,such as field explorations,multi-scale physical model tests,and numerical simulation methods,so as to reveal the physical description,internal structure,macroscopic mechanical properties of the landslide dams and their spatial and temporal variations;and then,a state-dependent(i.e.,gradation,pore ratio,and stress level)dilatancy equation for wide-graded landslide deposit will be presented,and a generalized elastic-plastic constitutive model that can adapt to complex stress paths and the limit equilibrium analysis method of landslide dam body will be establi

关 键 词：堰塞体 剪胀理论 本构模型 冲蚀特性 溃决机理 多场耦合 溃决模型 稳定性评价 

分 类 号：TV16[水利工程]