Compression Characteristics of Highly Compacted and Tamped Loess Soil Fills

A comprehensive compaction technology combining layered compaction by vibratory rollers and interlayer heavy tamping is proposed and applied to an embankment project to improve the compaction effects of high loess embankments. The compression characteristics of the highly compacted soil layers after re-tamping are investigated through soil mechanics tests and onsite settlement monitoring. The results of the soil mechanics tests show that the working mechanism of heavy tamping is a re-compacting effect. After the heavy tamping after layered rolling, the degree of compaction and compression modulus are greatly improved and change periodically with filling depth since tamping is conducted approximately every 3 m of filling. Compared with the condition of layered rolling using rollers only, the compression modulus was improved by 50–100% with comprehensive compaction, and the settlement of the fill body can be reduced by nearly 40%. The comprehensive compaction technology can be used to effectively reduce post-construction settlement and shorten the post-construction settlement period for the loess-filled high embankment. The post-construction settlement follows a logarithmic relationship with time. Therefore, a corresponding prediction formula for the post-construction settlement is proposed.