Mechanical Characterization of Soil–Rock Mixture Under Varying Block Parameters, Matrix Properties and Matrix Water Content Using Destructive and Non-Destructive Testing

Soil–rock mixtures, sometimes referred to as Bimrock, are complex geomaterials described as rock mixes with finer-textured matrices. The interaction between the matrix material and the blocks governs the mechanical behaviour and strength of Bimrock. However, the effect of modifying individual components' physical qualities on Bimrock's behaviour has received a lack of focus. This study investigated the unconfined compressive strength of soil–rock mixtures and its correlations with an ultrasonic pulse velocity test to analyse the failure morphology of soil–rock mixtures with different volumetric block proportions, block size, matrix saturation, and matrix types. This study demonstrated no significant effect of unconfined compressive strength when the sample has a 25% volumetric block proportion mixture and small-size blocks. This type of Bimrock behaves like a matrix-only geomaterial. The unconfined compressive strength was observed to be maximum for the silty loam matrix compared to loamy sand and sandy loam. The failure patterns differ according to matrix type, VBP, size of blocks, and moisture content. In addition, the ultrasonic pulse velocity was conducted for every sample, and the test results illustrated that matrix moisture content and block size are crucial factors in influencing the pulse velocity. The pulse velocity reduces as the fine content increases in the matrix. It increases as the block size increases in the block content.