The application of a meso-structural test system under continuous load in ecological soil

The ecological soil is a pollution-free and reusable soil, which has led to the revolution of sustainable development of the engineering construction. A meso-structure test system was developed to study the failure mechanism of ecological soil under continuous loads. This test system primarily contains the test apparatus and three image processing methods to acquire more accurate information of the meso-structure. Five parameters were employed to describe the meso-structure characteristics of ecological soil. A series of experiments were conducted to evaluate the meso-structure variation of ecological soil in the process of initiation, development and formation of shear band. The experimental results show that under continuous loads the shear band of ecological soil develops continually but at different rates in different stages. During the whole process the meso-structure parameters, including fracture area ratio, fracture distribution fractal dimension and grain orientation degree, all increase, while grain roundness and grain distribution fractal dimension show a downward trend. The results also indicate that the changes of all the parameters present three distinct phases, which are caused by the impact of the connection between the particles and aggregates.