本文根据实验和理论分析，提出一种单轴、三轴压缩试验的新的破坏判据，分析其机理是体积或密度连续原则的破坏。指出这一判据有可能应用在这种试验的自动控制上。同时讨论了低围压情况下土样单轴、三轴压缩试验橡皮套产生附加围压的影响及一种计算方法，用以校正Ｃ值的计算 Based on experimental and theoretical analysis, this paper proposes a new failure criterion for uniaxial and triaxial compression tests. The mechanism of the analysis is the destruction of the continuous principle of volume or density. It is pointed out that this criterion may be applied to the automatic control of this test. At the same time, the influence of the confining pressure produced by the rubber sleeves of the uniaxial and triaxial compression tests of soil samples under low confining pressure and a calculation method are discussed to calculate the correction of C values.