【摘要】 <正> 以往,土力学中计算土体变形应用的是弹性理论,土被简化为直线变形体.在稳定性分析中应用的是塑性理论,土体的强度的发挥与变形无关.这些不妥当的假定沿用了很长的时间,一直到电子计算技术应用于土力学,人们才可根据试验获得的土的应力～应变关系来计算实际土体的应力和应变分布,从而判断土体各点所处的状态是弹性平衡,还是塑性平衡,这种判定需要一个量标～抗剪强度指标.土的强度的确定,是个复杂的问题.它不仅与应力条件和排水条件有关,而且与变形密切关联,过去,人们是应用一定的破坏准则从土体更多还原

【Abstract】 The first section of the report presents failure shape of clay specimen and analyses of the inducing sources by mohr-theory. A soft layer within the specimen can effect and control the strength and the failure shape of clay; In the second section of the report the whole process of deformation of the clay specimen under external loads is analysed. The relationship be-tween the deformation and strength is stated. The meaning of statical lim-it-equilibrium condition, kinematical equilibrium condition and limit kin-ematical equilibrium is delineated. The differencnces under various equili-brium condition were discussed; In the last section the use and the exis-ting problems of the various failure criterias of soil are discussed.更多还原