This work aimed to understand the mechanical behavior of siliceous and calcareous sand materials under uniaxial confined compression loading at high stress levels. For this purpose, a series of quasi-oedometric compression tests were conducted on sand materials, to examine the effects of grain size, nature, and moisture contents on the soil crushability and the compression behavior, using an upgraded thick pressure vessel device that can reach mean stress up to 500 MPa. All samples were prepared using an aspect ratio of 1:1 (diameter: height), placed inside a high strength steel vessel, and compressed at a uniform axial displacement rate of 5 µm/s. The vessel is instrumented with multiple strain gauges allowing for the characterization of the hydrostatic and deviatoric behavior of each test. The results of quasi-oedometric tests, conducted on these types of sand, up to a passive confinement of 500 MPa, show that particle breakage is enhanced by the presence of water. It was noticed that, for siliceous sand, smaller particles break more than larger particles, and that the calcareous grains manifest a rapid response to axial stress compared to siliceous sand. Testing various soil properties shows a great potential to better characterize the sensitivity to breakage of soils. Lastly, a post-mortem analysis of samples before and after testing, using the X-ray micro-tomography technique, was applied to study the mechanical damage of sand specimens.

To quantify the erosion parameters and thus assess the erodibility of soils, hole erosion tests (HET) are used with methods of interpretation developed recently by researchers. The application of these methods requires some input data, and the most critical one is the final diameter of the eroded hole that is determined after completion of the test. The precision of the hole diameter after erosion leads to a better and more reliable evaluation of the soil’s resistance against erosion, more precisely the soil erodibility characteristics, τc (critical shear stress) and ker (erosion coefficient). In the present study, three methods for determining the final hole diameter are used: M1, direct weighing of the paraffin skeleton of the eroded hole; M2, differential mass of the sample before and after erosion; and M3, 3-D scanning technique of the paraffin skeleton. These methods were applied on five HET tests performed on soil samples containing the same percentage of Armorican kaolinite mixed with Hostun sand. The soil samples are compacted at different densities and to the optimum water content, as determined from a standard Proctor test. The results indicate that method M3 based on a 3-D scanner acquisition and processing of the skeleton volume after erosion compares very well with the more usual ones, M1 and M2, with the obvious advantage of providing the full 3-D reconstruction of the post-erosion hole, allowing further investigations (morphological analyses). Furthermore, an assessment of the uncertainty in predicting erodibility, particularly associated with the post-erosion diameter calculated through the three methods, was conducted and yielded satisfactory outcomes.