【作者】 王浩然；

【导师】 邵龙潭；

【作者基本信息】 大连理工大学 ， 工程力学， 2020， 硕士

【摘要】 边坡失稳是一种严重的地质灾害,灾害一旦发生就会造成大量人员伤亡与巨大财产损失,因此边坡稳定分析对于土工结构设计与灾害防治至关重要。同时,一些学者也认为,土压力与地基承载力问题亦可采用边坡稳定分析思想进行分析。目前工程应用中的边坡稳定分析方法大都存在一些不足,如,刚体极限平衡法需要引入一定假定条件才能求解;极限分析法计算过程较为复杂;有限元强度折减法在某些情况下可能会存在违背材料自身性质等问题。然而,有限元极限平衡法可以避免上述问题,该方法理论在任何工况下土体结构的稳定性分析中都可取得较好的效果。基于此,本文在前人研究的基础上,详细地介绍了有限元极限平衡法的理论,进而开发出了相应的计算程序,并将该程序应用于土体学三大经典问题的分析,同时与传统理论得到的结果进行对比。本文主要完成了以下工作:(1)讨论了土体内一点的极限平衡状态与土体沿整个滑动面的极限平衡状态之间的关系,在此基础上定义了土体沿整体与局部滑动面的安全系数,并以此作为土体整体与局部稳定性评价标准。(2)采用粒子群算法与模式搜索法结合进行临界滑动面的搜素,提高了局部和全局搜索能力,通过生成局部微小滑动面的方式实现了局部破坏区的搜索,并基于Qt框架与Python语言开发了相应程序。(3)本文中基于有限元极限平衡法开发的程序与传统理论方法在边坡稳定分析中得到的结果进行对比,有限元极限平衡法计算得到的临界滑动面上土体剪应力与抗剪强度分布符合实际特征,其位置和安全系数与瑞典圆弧法、简化Bishop法、有限元强度折减法得到的结果一致性较好。在土压力问题中,有限元极限平衡法得到的局部破坏区与临界滑动面符合Rankine土压力理论。在地基承载力分析中,采用逐渐增加地基载荷的方式,得到了地基的渐进破坏过程,有限元极限平衡法得到的极限载荷与Prandtl理论计算的结果同样具有较好的一致性。更多还原

【Abstract】 As a serious geological disaster,landslides will cause a large number of casualties and huge property losses.Therefore,slope stability analysis is very important for the design of geotechnical structures and landslide disaster prevention.Some scholars believe that the problem of earth pressure and foundation bearing capacity can also be analyzed by the theory of slope stability analysis.At present,most of the slope stability analysis methods in engineering applications have some deficiencies.For example,the rigid body limit equilibrium method requires certain assumptions to be solved;the limit analysis method calculation process is more complicated;the finite element strength reduction method may exist in some cases Problems that violate the nature of the material.However,the finite element limit equilibrium method can avoid the above problems,and the theory of this method can achieve good results in the stability analysis of soil structures under any working conditions.Based on previous studies,this paper introduced the theory of the finite element limit equilibrium method in detail,and develops a calculation program.Using the program to analyze the three classic problems of soil science and compare them with the results obtained by traditional theory to prove the reliability of the program.The main work are as follows:(1)The relationship between the limit equilibrium state of a point in the soil and the limit equilibrium state of the soil along the sliding surface is discussed.On this basis,the safety factors of the soil along the whole and local sliding surfaces are defined,and use them as the evaluation criteria for the overall and local stability of the soil.(2)The particle swarm algorithm and Hooke-Jeeves search method are used to search for the critical sliding surface,which improved the local and global search capabilities.The search for the local damage area is achieved by generating some local small sliding surfaces.The program was developed in Python language.(3)In this paper,the program developed based on the finite element limit equilibrium method is compared with the results obtained in the slope stability analysis by traditional theoretical methods.The distribution of the shear stress and shear strength of the soil on the critical sliding surface calculated by the finite element limit equilibrium method is satisfied with the actual feature,its position and safety factor are consistent with results of the Ordinary method,simplified Bishop method,and finite element strength reduction method.The results obtained by the reduction method are not much different.In the analysis of the earth pressure problem,the local failure and the critical sliding surface obtained by the finite element limit equilibrium method conform to Rankine earth pressure theory.In the analysis of the bearing capacity of the foundation,the progressive failure of the foundation is obtained by gradually increasing the foundation load.The limit load obtained by the finite element limit equilibrium method is similar to the result calculated by the Prandtl theory.更多还原