木质素磺酸钙改良的低液限黏土三轴压缩特性

通过对具有不同木质素磺酸钙掺量、不同养护时间的改良低液限黏土进行一系列三轴剪切试验，分析了改良土应力应变曲线、峰值偏应力及抗剪强度参数的变化规律，结合扫描电镜探究了其内在机制。试验结果表明：木质素磺酸钙的掺入能够显著提升土体抗剪强度，随着掺量的增加，改良土的抗剪强度先增加后减小，最优掺量为8%;随着养护时间的增加，改良土的抗剪强度提升，且增强速度逐渐变缓；养护7 d后8%掺量的改良土获得最大峰值偏应力2 017.23 kPa,比养护相同时间的纯黏土高236.25%;改良土黏聚力随着木质素磺酸钙掺量的增加先增加后减小，而内摩擦角增大到一定值后趋于稳定。改良土强度提升的内在机制可以概括为填充孔隙、离子交换、吸附包裹土粒以及胶结土粒团聚体。

Triaxial compression properties of calcium lignosulfonate-modified low liquid limit clay

A series of triaxial shear tests were carried out on improved low liquid limit clay with different amounts of calcium lignosulfonate (Ca-LS) and different curing time. The law of the stress-strain curve, peak deviator stress and shear strength parameters were analyzed. The internal mechanism of the improved soil was analyzed with the scanning electron microscope. The test results show that Ca-LS can significantly improve the shear strength of clay. With the increase of Ca-LS content, the shear strength of improved soil first increases and then decreases, and the optimal content is 8%. With the increase of curing time, the shear strength of the improved soil becomes stronger, but the strengthening speed gradually slows down. After 7.d of curing, the peak deviator stress of the improved soil containing 8% of Ca-LS is 2 017.23.kPa, which is 236.25% higher than the pure clay that cured for the same time. The cohesion force of the improved soil first increases and then decreases with the Ca-LS content, and the internal friction angle of the improved soil first increases and then remains stable. The internal mechanism of the modified soil strength improvement can be summarized as filling pores, ion exchange, adsorption of wrapped soil particles and cemented soil particle aggregates.