Laboratory Investigation on Particle Breakage Characteristics of Calcareous Sands

Abstract

Many studies have demonstrated the fragility of calcareous sands even under small stresses. This bears an adverse influence on their engineering properties. A series of laboratory tests were carried out on poor-graded calcareous sands to investigate the crushability mechanism. Einav’s relative breakage and fractal dimension were used as the particle breakage indices. The results show that the particles broke into smaller fragments at the low-stress level by attrition which was caused by friction and slip between particles. In contrast, particles broke in the form of crushing at the relatively higher stresses. The evolution of the particle size was reflected by the variation in Einav’s relative breakage and fractal dimension. As testing commenced, the breakage index rapidly increased. When the stress was increased to 400 kPa, the rate of increase in the breakage index was retarded. As the stress was further increased beyond 800 kPa, the rate of increase in the fractal index became much smaller. This elucidated that the well-graded calcareous sands could resist crushing depending on the range of applied stresses. Based on the test findings, a new breakage law is proposed.

Changes in biochemical constituents and antioxidant enzyme activity in groundnut (Arachis hypogaea L.) by the addition of coated multi-nutrient fertilization in calcareous soil

“…Groundnut (Arachis hypogaea L.) serves as the world's largest source of edible oil, and ranks second among oilseed crops (Saranyadevi and Mohideen, 2022) in 70% of the world's groundnut cultivation occurs in the semi-arid and tropics, where the soils are predominantly calcareous and alkaline (Manasa et al, 2020). Soil calcareousness is the major growth limiting factor that limits plant growth and yield due to its poor soil organic matter and high pH with lesser availability of essential plant nutrients (Chen et al, 2021). The availability of essential nutrients such as phosphorous, sulphur, boron, zinc, iron, copper and manganese were deficient in calcareous soils due to various chemical reactions like precipitation, fixation and adsorption.…”