Experimental Study on the Time-Dependent Oedometric Compression Behavior of Calcareous Sand

A series of compression tests were carried out on two types of calcareous sand to study the time-dependent behavior of calcareous sand under oedometric conditions. Consolidation, creep, stress relaxation, and constant strain/stress rate tests were conducted. At the same time, the effects of input energy and grain shape on particle breakage were investigated. The test results show that a large amount of particle breakage occurs in the calcareous soils under different modes of loading, leading to a significant time effect on the oedometric compression responses. Under the same level of vertical stress, the large-grain calcareous sand has a higher creep or relaxation rate. Over-consolidated sand has a much smaller creep or relaxation response than normally consolidated sand, and the response decreases with an increase in the overconsolidation ratio. Loading rate has an influence on the compressibility of calcareous sand, especially when the particle breakage is significant. In addition, it is also shown that a unique relationship exists between the relative breakage and the input energy for the same kind of calcareous sand, which is independent of the loading mode.