压实黄土抗剪强度参数影响因素研究

为了进一步研究河南三门峡地区黄土抗剪强度的影响因素,采用应变控制式三轴仪对不同含水量、不同压实度下的重塑黄土进行不固结不排水三轴试验。试验结果表明:相同压实度下,随着含水量的增加,应力应变关系曲线由弱应变硬化向强应变硬化转变;粘聚力与内摩擦角均随含水量的增加而减小,粘聚力与含水量的变化呈明显负线性相关,内摩擦角与含水量无明显的相关性。相同含水量下,粘聚力与内摩擦角随压实度的增加而逐渐增大,且呈现出明显的指数相关。含水量对抗剪强度参数的影响比压实度大。对以上强度参数采用最小二乘法进行拟合,得出考虑含水率和压实度的抗剪强度相关关系式,能够较为准确的反映在某种试验条件下强度参数的变化规律,为实际工程应用和数值模拟提供依据。

Study on Influencing Factors of Shear Strength Parameters of Compacted Loess

In order to study the influencing factors for shear strength of remolded loess in Sanmenxia area, a series of unconsolidated-undrained triaxial tests were carried out. The specimens with different water contents and compaction degrees were adopted in the tests. The results show that the stress-strain curve at the same compaction degree changes from weak strain hardening to strong strain hardening with the increase of water content. The cohesion and the internal friction angle both decrease with the increase of water content. A negative linear relationship was observed between the cohesion and the water content, but there is no obvious correlation between the internal friction angle and the water content. The cohesion and the internal friction angle both increase with the increase of compaction degree at a given water content. An obvious exponential correlation between them was disclosed. The results also illustrate that the water content has a greater influence on shear strength parameters than compaction degree. On the basis of the Coulomb formula, the relationship between shear strength parameters and the affecting factors including water content and compaction degree were obtained using the least square method. The presented formula can reflect the variation law of strength parameters under certain experimental conditions. Research findings can provide bases for engineering application and numerical simulation.