Compaction of the Railway Embankments During the New Highspeed Lines Construction

The Technical Regulations acting at present time on the highspeed lines construction has severe requirements to the quality of the railway embankments construction. They have to be practically without settlement and work at the stage of the elastic deformations. The purpose of this investigation is to study the process of soils compaction under repeated loads applications, which should have the amplitude- frequencies parameters such as produced by the highspeed running trains. Therefore, a special dynamic triaxial test apparatus was used for the laboratory investigation. The major features of this apparatus were to simulate the wave forms of the vibrations initiated by passing trains. The equipment and experimental procedure are described herein, as well as main results of testings. The first part of the report devoted to the theoretical substantiation of the possibility of the railway embankments construction without settlements. In the second part, the dynamic triaxial tests of the clay soils initially subjected to the elastic compression are described. The character of the void ratio changing during the dynamic elastic compression as compared with the static compression as well as the strength of the soils changing are shown. As the results, the method of compaction of the embankments to be applied during the new highspeed railroads construction is proposed.