等应力比平面应变试验中主应力转换的研究

土的平面应变是岩土工程中常见的状态，其中零应变方向的主应力是十分复杂的。承德中密砂等应力比平面应变试验结果表明，平面应变状态下零应变方向的主应力在不同条件下可能是大主应力、中主应力或者小主应力。利用由等应力比三轴压缩试验确定的切线泊松比，可以合理地预测等应力比平面应变试验中零应变方向主应力的转换过程，这一认识对于一些实际工程问题的分析具有一定的意义。

Study on transforming of principal stresses in constant stress ratio plane strain tests

Plane strain state is familiar in geotechnical engineering,and estimating the principal stress in the plane strain state is very complicated.Based on the results of constant stress ratio plane strain tests,an interesting conclusion is drawn that the principal stress in the direction in which the principal strain keeps zero may be major principal stress,intermediate principal stress or minor principal stress.By using the tangent Poisson's ratio obtained from constant stress ratio triaxial compression tests,the behavior that the principal stress in zero strain direction transforms in constant stress ratio plane strain tests could be predicted.This conclusion is meaningful for analyzing some problems during engineering practice.