初始各向异性对软土力学特性影响研究

Study on Influence of Initial Anisotropy on Mechanical Properties of Soft Soil

开展固结排水剪切试验和场发射扫描电子显微镜试验研究不同沉积角度软土的宏观微观特性,并基于图像处理技术和分维理论研究初始各向异性对软土的力学特性影响的微观机理。结果表明:与不同沉积角度试样的峰值强度及初始切线模量为各向异性的,其中与沉积呈0°方向的强度和模量最高,颗粒及孔隙的形状分维数最大。形状分维数随着角度的升高而降低,复杂度随之减小,黏附力降低,以致土的强度也随之降低。孔隙定向角分布具有各向异性,初始各向异性会影响剪切作用下颗粒的重定向分布。

Consolidation-drained shear test and field emission scanning electron microscope test(FESEM)were carried out to study macro-and microscopic characteristics of soft soil with different deposition angles.Based on image processing technology and fractal dimension theory,the micro mechanism of mechanical properties for soft soil influenced by initial anisotropy was revealed.The results show that the peak strength and initial tangent modulus of soft soil with different deposition angles are anisotropic.The strength and modulus in the deposition direction of 0°are the highest,and the fractal dimension of particle and pore shape is the largest.With the increase of angle,the fractal dimension of shape decreases,the complexity decreases,the adhesion decreases,and the strength of soil decreases.The pore orientation angles are anisotropic,and the particle reorients subjected to shearing are influenced by initial anisotropy.