CaCO_3与砂改良高液限红黏土对比试验研究

Research on comparative tests of CaCO_3 and sand improved high liquid limit red clay

基于高液限红黏土的特殊性质,利用CaCO_3和砂对其进行改良,通过直剪试验和无侧限抗压试验探讨两种改良土样的强度指标与掺料比的关系.研究表明:CaCO_3和砂均能改变高液限红黏土的性质.改良后土样的黏聚力和内摩擦角均比改良前高,掺CaCO_3改良土样的黏聚力和内摩擦角在掺料比为40%时达到最大,且整体的黏聚力和内摩擦角值比掺砂改良的土样大.随着掺料比的增大,掺CaCO_3改良土的无侧限抗压强度逐渐减小;而掺砂改良土的无侧限抗压强度则呈先增强后减弱趋势,掺料比为10%时出现最大值;当高液限红黏土的含水率为40%时,CaCO_3改良土最优的掺料比为40%.

Based on the unique nature of high liquid limit red clay, the research makes use of CaCO_3 and sand to improved clay and explores the relationship of their strength index and proportion of additive through direct shear test and non-lateral compression without lateral confinement test. The results show that both CaCO_3 and sand can change the nature of high liquid limit red clay. The cohesion and internal friction angle of the improved clay is greater than before, the cohesion and internal friction angle of the improved clay containing CaCO_3 reach its maximum when the admixture ratio is 40 %, overall cohesion and internal friction angle values is larger than soil mixed with sand samples. With the increase of additive proportion, the unconfined compressive strength of the improved clay with CaCO_3 decreases. The unconfined compressive strength of the improved clay with sand is showed a trend of first increased after decreased, maximum occurs when admixture ratio is 10 %. When the moisture content of high liquid limit red clay was 40 %, the optimal additive ratio of CaCO_3 improved soil is 40 %.