一、前言土的变形问题,已成为土力学的主要课题。可是,自库伦(Coulomb)、朗肯(Rankine)以来,却主要关心于土的应力关系。原因在于,土的应力应变关系复杂,其特性难于掌握。因此,土的平衡问题,避不开超静定。作为这一问题的解决办法,本质上都是一样的。不论是库伦提出的滑动线的意见,还是朗肯提出的极限平衡的概念,都实现了静定化,其成果至今在土力学的各分支有着大的影响。事实上,关于土的剪切 I. INTRODUCTION The problem of soil deformation has become a major topic of soil mechanics. However, since Coulomb and Rankine, they have been mainly concerned with the stress relationship of soil. The reason is that the stress-strain relationship of soil is complex and its characteristics are difficult to grasp. Therefore, the problem of soil balance cannot be avoided by static indeterminate. The solution to this problem is essentially the same. Whether it is the observation of the sliding line proposed by Coulomb, or the concept of limit equilibrium proposed by Rankine, all the static definiteizations have been achieved, and their results so far have a great influence on the various branches of soil mechanics. In fact, about the cutting of soil