Study on Basic Mechanical Properties of High Fill Materials in Chongqing

The high-fill project sites in Southwest China are mostly made by cutting mountains and filling valleys after blasting. The laboratory physical properties and direct shear tests were carried out to analyze the influence of rock content and water content on the shear strength index of soil-rock mix under different consolidation pressures. The results show that the cohesion of soil-rock mixture is positively correlated with the rock content, and the incremental effect of cohesion is most obvious when the rock content increases from 20% to 40%; the internal friction angle of the filler in the early stage shows a trend of increasing and then decreasing with the increase of rock content, and in the later stage with the increase of the rock content, the reduction of the internal friction angle has a significant effect. The cohesion is negatively correlated with the water content, and the decrease of cohesion is obvious when the water content increases from 5% to 8%; the internal friction angle of the filler shows the same trend of increasing and then decreasing with the increase of water content. According to the results of the indoor test, a range of values of shear strength index is given for the project site, and the corresponding key parameters can provide reference for similar projects.