stress đường dẫn Một cách thuận tiện để đại diện cho các kết quả kiểm tra, và thư từ của họ với những căng thẳng trong lĩnh vực này, là sử dụng một con đường căng thẳng. Trong kỹ thuật này nhấn mạnh một điểm được đại diện bởi hai (có lẽ ba) các thông số đặc trưng, và họ được vẽ trong một sơ đồ. Sơ đồ này được gọi là một con đường căng thẳng. | Chapter 26 STRESS PATHS A convenient way to represent test results and their correspondence with the stresses in the field is to use a stress path. In this technique the stresses in a point are represented by two perhaps three characteristic parameters and they are plotted in a diagram. This diagram is called a stress path. Parameters It is assumed that the state of stress in a point can be characterized by the average stress the isotropic stress 1 ơi ơ2 ơ3 and the difference of the major and minor principal stresses ơ1 ơ3. By doing so it is assumed that the behavior of a soil depends only upon these two parameters. This means that it is assumed that other parameters such as the intermediate principal stress ơ2 or the direction of the major principal stress are unimportant. ơ zx Alternatively the average value of the ma jor and minor principal stresses 2 ơi Ơ3 may be used rather than the average stress. The two variables will be denoted by ơ and T Ỷ ơxz ơ xx ơzz Figure Mohr s circle and stress point. ơ 2 ơi Ơ3 T 1 ơi ơ3 . The introduction of the factor 2 in the two definitions results in ơ and T being the location of the center and the magnitude of the circle in Mohr s diagram see Figure . By choosing these parameters it is implicitly assumed that other parameters are unimportant for the description of ơ the material behavior of the soil. It is assumed for instance that the intermediate principal stress is unimportant as is the orientation of the principal stresses. This is approximately correct for the failure state of a soil because the Mohr-Coulomb failure criterion can be formulated in ơ and T but for smaller stresses it may be a first approximation only. Actually even the failure criterion of a soil is often found to be dependent on 151 Arnold Verruijt Soil Mechanics 26. STRESS PATHS 152 other parameters such as the value of Ơ2 too so that the Mohr-Coulomb failure criterion should be considered as merely a first approximation of real .