Application of non-contact testing technology in model tests on press-in piles

Based on the digital image correlation technology, the displacement information of the soil in the model pile tests is obtained without marking and touching the surface, and the displacement laws of the soil is analyzed. The calculation program is compiled by using the MATLAB. The soil displacement and its change at any position and at any time in the tests can be extracted by calculation. In addition, the soil displacement caused by different pile types and different diameters is dynamically analyzed, and the displacement trajectory of the soil is fitted. At the same time, by setting up a local camera, the disturbance layer at the pile-soil interface is observed and analyzed. The study shows that the horizontal displacement of soil increases gradually to stability during pile press-in. When the diameter of the pile is the same, the soil-squeezing effect of the square pile is obviously stronger than that of the circular pile, and the difference between them is more obvious at the deep depth of the soil. But when the discharge volume is the same, the difference between the square pile and the circular pile is small. The thickness of the disturbance layer is about 5.7~8.6 d₅₀ and the soil in this layer moves downward when the pile passes through, the displacement of the layer gradually decreases.