Influence of the wide range cement content on the properties of cement–treated marine soft soil and bound method of semi–solidified soil

In order to identify the upper and lower boundary cement content for modified marine soft soil (i.e., semi–solidified soils), physical, compaction, and unconfined compressive strength tests of cement–treated soils with a wide range of cement content were carried out to study their variation law of physical–compaction–mechanical properties. The test results show that cement–treated soil can be divided into uselessly treated soil, semi–solidified soil, and solidified soil with the increase of cement content. For uselessly treated soil, the treated soil cannot be compacted even after compaction delay. Cement hydration in semi–solidified soil significantly improved its physical and compaction properties. However, compaction destroyed the skeleton structure of solidified soil, resulting in lower strength than compacted semi–solidified soil. Based on the cement–soil particles–water relationship, soil particles–water transfer mechanism, cement hydration mechanism and the state of soil particles–water before and after treated, the bound method of semi–solidified soils based on cement content and moisture content ratio of untreated soil was established. The test parameters of bound method are simple, easily obtained and have small dispersion, which provides design basis and theoretical support for resource utilization of marine soft soil.