Dafalla Muawia, Shaker Abdullah, Elkady Tamer, Almajed Abdullah, Al-Shamrani Mosleh
Bughshan Research Chair in Expansive Soils, King Saud University, Civil Engineering, Riyadh, 11421, Saudi Arabia.
Civil Engineering, King Saud University, Riyadh, 11421, Saudi Arabia.
Sci Rep. 2020 Oct 26;10(1):18226. doi: 10.1038/s41598-020-75188-1.
This study investigated shear strength behaviour of compacted sand-clay mixtures used as liners, with 10%, 20%, and 30% clay contents. A natural high-plasticity and highly expansive clay found in the eastern province of Saudi Arabia was used. A series of consolidated undrained triaxial tests and pore water pressure measurements of saturated samples with various clay contents and confining pressures was conducted using a computer-controlled Bishop and Wesley triaxial cell. The unit was equipped with pressure volume controllers and a pressure transducer for measuring sample volume changes and excess pore water pressure. The experimental test results indicate that clay content and confining pressure significantly affect stress strain response curves, pore water pressure generation curves, and steady-state shear strength. Sand-clay mixtures with clay content less than 10% showed a tendency toward contractive behaviour. The failure line slope increased in accordance with clay content increase. The deviator stress versus axial strain of saturated sand-clay mixtures indicated a hyperbolic trend. The stress ratio versus axial strain representation was more informative for the shear strength behaviour assessment. Clay content did not significantly affect critical-state friction angle. Scanning electron microscope images of the sand-clay mixtures with different clay contents are presented.
本研究调查了用作衬垫的压实砂 - 粘土混合物的抗剪强度特性，其中粘土含量分别为10%、20%和30%。使用了在沙特阿拉伯东部省份发现的一种天然高塑性和高膨胀性粘土。采用计算机控制的毕肖普和韦斯利三轴试验仪，对不同粘土含量和围压的饱和试样进行了一系列固结不排水三轴试验和孔隙水压力测量。该试验仪配备了压力体积控制器和一个压力传感器，用于测量试样体积变化和超孔隙水压力。试验结果表明，粘土含量和围压显著影响应力应变响应曲线、孔隙水压力生成曲线和稳态抗剪强度。粘土含量小于10%的砂 - 粘土混合物表现出收缩行为的趋势。破坏线斜率随着粘土含量的增加而增大。饱和砂 - 粘土混合物的偏应力与轴向应变呈双曲线趋势。应力比与轴向应变的关系对于抗剪强度特性评估更具信息量。粘土含量对临界状态摩擦角没有显著影响。给出了不同粘土含量的砂 - 粘土混合物的扫描电子显微镜图像。
