Abstract: Many scholars have performed a large amount of researches on soil strength with considerable achievements. But the influence of soil structure on its strength has always been the difficult point. A soil structure strength model is established based on soil particle connection. From the analysis of this soil structure model established, it is found that the strength of soil mass is directly associated with the connection strength among particles and the distribution pattern of connections. When the stress-strength curve family in statistical domains is used to macroscopically analyze the soil mass properties, the yield surface composed of several curved surfaces can be gained. The analysis of examples of simplified soil structure morphology indicates that an isotropic stress-strength model can be obtained when the connection in each direction is evenly distributed. In addition, when the spatial characteristics of statistical domains are considered, for different local coordinates of macroscopic stress in the statistical domain, the stress gradient may influence the soil strength. This is exactly what the classical theories can not explain. Therefore, the strength model of soil structure being established is a kind of new and effective analysis method for structural soil.

Key words: particle structure, model, strength theory particle structure, model, strength theory particle structure, model, strength theory