摘要
在中国力学学会岩土力学专委会主办的“三峡库区地质灾害专题研讨会”上,与会专家以边(滑)坡引发的地质灾害为背景,集中讨论边(滑)坡工程治理中的力学问题。第一个中心议题关系到岩土材料的屈服与破坏准则,指出屈服与破坏的不同、屈服准则的不同形式,尤其是提出岩土材料统一强度理论、摩擦能的概念与岩土能量屈服准则以及基于三剪强度理论的智能岩土屈服准则;探讨岩土材料破坏准则及其可以表述的各种形式,提出应变表述的破坏准则,并研究砂土剪切带形成与渐进破坏进程;介绍我国应用能量原理研究岩石破坏机制及岩体水力劈裂机制的进展。第二个中心议题重点讨论边(滑)坡稳定分析方法中的有关问题,如边(滑)坡安全系数定义的分析与选用,提出c,?的双安全系数(双折减系数)的定义及其计算方法;讨论边(滑)坡传统稳定分析方法与数值方法的进展,提出多种新的解法,并进行相互比较。在传统稳定分析方法中给出简化Bishop法的解析解、边坡三维分析准严格极限平衡法以及用滑移线对边坡滑动区划分单元的运动单元法,并用于分析研究边坡在干湿循环条件下的长期稳定性,进一步扩展边坡传统分析方法。数值分析方法中,除应用有限元、离散元、有限差分等方法外,土体渗流分析与有限元强度折减法结合的边坡稳定分析方法正在迅速发展,并在边坡稳定分析中从经典弹塑性力学扩展到非平衡态弹塑性力学,从岩体变形理论扩展到岩体变形控制与加固理论。这表明数值分析在边坡稳定分析与边坡加固中将逐渐起主导作用。肯定有限元强度折减法的可行性、优越性与实用性,提出在其应用中需要解决的一些问题及应用中的一些经验,并把强度折减法应用到离散元法与岩石破裂过程分析方法中。研究讨论有限元强度折减法中岩土结构失稳破坏的判据,提出多种判据,主要有滑面上塑性应变或位移出现突变、有限元数值计算不收敛及从坡角到坡顶塑性区贯通等。但至今尚无一致的意见,认为各种判据的结果相差不大,与传统方法接近。最后,提出边坡三维分析的准严格传统方法与基于强度折减的数值分析方法,向三维分析迈进一大步。
In the special topic proseminar on geologic disasters in the Three Gorges Project Region sponsored by Committee of Rock and Soil Mechanics,Chinese Society of Theoretical and Applied Mechanics,aimed at the geologic disasters resulted from slope and landslide,specialists focus on the mechanical problems in the slope and landslide engineering.The first topic is about the yield and failure of geomaterials.The differences between yield and failure are pointed out;different expression forms of yield criterion are listed,especially the unified strength theory,the conception of friction energy,the energy yield criterion,and the intelligent yield criterion based on triple shear strength theory of geomaterials are put forward.Geomaterials′ failure criterion and its different expression forms are discussed;the strain failure criterion is deduced;and the processes of shear band formation and gradual failure of sand are researched.The advances of researching rock failure and hydraulic fracture mechanism by energy method are introduced.The second topic is about some problems in slope and landslide stability analysis including the analysis and selection of slope and landslide safety factor definition,the definition and computation method of double safety factor（double reduction factor）.The developments of traditional stability analysis methods and numerical methods are discussed;and some new methods are proposed and intercompared.In traditional stability analysis methods,the analytical solution of simplified Bishop method,the quasi-rigorous limit equilibrium method for three-dimensional slope analysis and the kinematical element method meshing slip section of slope using slip line are presented.In addition,the long-time stability of slope under drying and wetting cycle conditions is researched with shakedown theory,which extends the traditional slope analysis methods.In numerical methods,besides finite element method,discrete element method and finite difference method,the slope stability analysis method combining soil seepage analysis and finite element strength reduction method are being developed rapidly.Moreover,the slope stability analysis extends from classical elastoplastic mechanics to nonequilibrium elastoplastic mechanics,and from rock mass deformation theory to rock mass deformation control and reinforcement theory,which means numerical analysis will play a dominant role gradually in slope stability analysis and reinforcement.The feasibility,superiority and practicability of finite element strength reduction method are affirmed;some shortages and experiences in its application are proposed;and it′s also applied to discrete element method and rock failure process analysis（RFPA） method.The structure instability and failure criteria in computation for finite element strength reduction method are discussed.Many criteria are put forward,such as the saltation of plastic strain or displacement in slip surface,nonconvergence of finite element numerical computation,plastic zone connection from the top to the bottom of the slope and so on,but no consistent opinions are achieved yet.The results of various criteria have little difference,and are close to those of traditional methods.At last,the quasi-rigorous traditional methods and numerical methods based on strength reduction for three-dimensional slope analysis are brought forward,and it′s a huge advance toward three-dimensional analysis.
出处
《岩石力学与工程学报》
EI
CAS
CSCD
北大核心
2007年第4期649-661,共13页
Chinese Journal of Rock Mechanics and Engineering
基金
国家自然科学基金资助项目(40318002)
关键词
边坡工程
岩土材料
屈服准则
破坏准则
极限平衡法
有限元强度折减法
安全系数
三维分析
slope engineering
geomaterials
yield criterion
failure criterion
limit equilibrium method
finite element strength reduction method
factor of safety
three-dimensional analysis
