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天然软土剪切带性状分析一直是岩土力学界的一个研究重点。采用电镜扫描和压汞法对珠海海积软土剪切带内外以及带边缘微观结构进行定量分析,研究结果表明:珠海软土的应力-应变曲线在低围压下表现出明显应变软化特征;软土在剪切破坏后,剪切带内的微观参数变化率最大,其次是剪切带边缘,最后是剪切带外;剪切带边缘上的颗粒逐渐沿着剪切应力的方向呈定向排列,而剪切带内,由于颗粒发生破碎、折断,颗粒排列是随机的,在剪切带外,颗粒的排列受剪切破坏的影响较小;珠海海积软土的孔隙入口孔径分布为主单峰分布,其主峰峰值的位置是沿着剪切带外——带边缘——剪切带内转移;Roscoe理论和Arthur经验公式预测的剪切带倾角与实测值相比都偏小,不适宜黏性土的剪切带倾角预测计算;Mohr-Coulomb理论计算出的倾角与实测值比较一致。
Natural soft soil shear zone character analysis has been a focus of research in geomechanics. The results show that the stress-strain curve of Zhuhai soft soil shows obvious strain-softening characteristics under low confining pressure. The microstructure of Zhuhai soft soil is characterized by SEM, After the shear failure, the change rate of microscopic parameters in the shear band is the largest, followed by the shear band edge, and finally the shear band; the particles on the edge of the shear band gradually follow the direction of the shear stress In the shear band, the particle arrangement is random and the particle arrangement is random. In the shear band, the particle arrangement is less affected by shear failure. The pore inlet pore size distribution of the Zhuhai seabed soft soil is In the main monomodal distribution, the position of the main peak is along the shear band, and the shear band dip predicted by Roscoe theory and Arthur empirical formula is smaller than the measured value. It is unsuitable for predicting the dip angle of shear zone in cohesive soil. The dip calculated by Mohr-Coulomb theory is in agreement with the measured value.