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墙体位移是影响土压力的核心要素。根据Rankine土压力模型,以试样在单剪试验中的剪切过程近似模拟墙后土体由静止进入极限状态的历程,构建土体剪应变与墙体位移在等极限应变条件下的几何方程和基于点应力状态的剪应力与土压力平衡方程,结合以双曲线表达且与几何方程相匹配的剪应变–剪应力理想非线弹塑性物理模型,建立综合反映土体变形与强度特性及初始应力状态影响的墙体位移–土压力函数关系,讨论极限状态下墙体位移的主要影响因素。分析表明:静止与被动(或主动)状态之间的墙体位移–土压力曲线是土体应力–应变特性的宏观体现,两者随变形的增加呈现出相似的变化规律;主动(或被动)状态下的墙体位移随土体极限剪应变、滑移区范围的增加而增大,随静止土压力系数的降低而减小(或增大);工程设计常用力学指标下的粗细粒土进入主动状态时,墙体位移与墙高之比为0.6‰~15.0‰,被动时为-0.5%~-5.9%,理论分析与相关文献模型试验结果吻合。
Wall displacement is the core element of earth pressure. According to the Rankine soil pressure model, the shear process of the specimen in a single shear test is used to simulate the course of the soils moving from the static limit state to the limit state. The geometrical equations of the soil shear strain and wall displacement under the condition of the same ultimate strain Based on the equilibrium equations of shear stress and earth pressure under the state of point stress, combining with the ideal non-linear elastic-plastic physical model of shear strain-shear stress that is expressed by hyperbola and matched with geometric equation, the deformation and strength characteristics and initial The relationship between wall displacement and earth pressure which is influenced by stress state is discussed. The main influencing factors of wall displacement under extreme state are discussed. The analysis shows that the wall displacement-soil pressure curve between the static and the passive (or active) state is the macroscopic manifestation of the stress-strain characteristics of the soil, both of which show a similar variation with the increase of deformation. The active (or passive) The displacement of the wall under the state increases with the increase of the ultimate shear strain and slip area of the soil and decreases (or increases) with the decrease of the static earth pressure coefficient; In the active state, the ratio of wall displacement to wall height is 0.6 ‰ ~ 15.0 ‰ and passive is -0.5% -5.9%. The theoretical analysis is in good agreement with the results from the model test.