冻融作用对海相软土压缩性及抗剪强度影响研究

为揭示原状海相软土冻融前后变形及强度差异性，对宁波原状海相软土及不同冻融条件下的融土进行了压缩实验和三轴固结不排水剪切实验。研究结果表明：单向冻结条件下，冻融作用使海相软土压缩性增强，且对试样不同部位处产生的影响程度不同，对靠近冷端的下部融土压缩性影响最大，中部其次，上部最小；冷端温度越低，冻融作用对融土压缩性影响越小，且逐渐趋于稳定；自然解冻比强制解冻对融土压缩性影响程度更大。冻融作用使融土黏聚力明显减小，内摩擦角略有增大；冷端温度越低，冻融作用对黏聚力和内摩擦角影响程度越大，在一定法向应力范围内，融土破坏强度越小。

A study on influence of freezing and thawing on compressibility and shear strength of marine soft soil

In order to reveal the difference in deformation and strength of undisturbed marine soft soils before and after freezing and thawing, compression tests and triaxial consolidation undrained shear tests were performed on the undisturbed Ningbo marine soft soil and the thawing soil under different freezing and thawing conditions. The results show that under the condition of one-way freezing, the freezing and thawing effect enhances the compressibility of the marine soft soil, and the degree of influence on different parts of the sample is different. The compressive property of the lower part near the cold end has the greatest effect, and the middle part has the second and the upper part has the smallest effect. The lower the temperature of the cold end, the smaller the effect of freezing and thawing on the compressibility of the thawing soil, and tends to be stable gradually. Natural thawing has a great influence on compressibility of thawing soil than forced thawing. Freezing and thawing effect obviously decreases the cohesive force of the thawing soil and slightly increases the internal friction angle. The lower the temperature of the cold end, the greater the effect of freezing and thawing on the cohesion and internal friction angle, and the smaller the failure strength of the thawing soil within a certain range of normal stress.