On Frost Heave Characteristics Of Different Fines Contents’ Graded Broken Stones Mixed With Cements

The non-ballasted track has a strictly demanding for the deformation of the system under rail. Laying the non-ballasted track in the Northeast severe cold region and due to its extremely sensitivity to the frost heave, it occurs an important task for Harbin-Dalian passenger line subgrade now and following-up operations how to control the deformation within the permitted standard range of the non-ballasted track.This paper has studied the factors which effect the frost heaving of graded broken stones such as fines content, the water mass fraction and temperature, cement contents’influence on the frost heave rate,mechanical properties and durability of the graded broken stones based on the Key Program for Science and Technology Development promoted by Former Ministry of Railways which reads "On Continuous Observation Techniques and Frost Heaving Remediation Technology along Harbin-Dalian High-Speed Rail Operation". The influence of fines content,water mass fraction, temperature on the graded broken stones has been analyzed as well as that of cement contents on the frost heave characteristics, mechanical properties and durability. Based on this, the reasonable suggested value of cement contents has been proposed. The major researches and tested results are list below:1. With the cement contents as zero, and the fines contents as3%,5%,8%,12%respectively,the four sets of sample had been conducted the frost heave tests in situ under the conditions of different water mass fractions.the result shows that the fines content and the water mass fraction are the key factors effecting the frost heave rate of the graded broken stones.The more the fines content and the water mass fraction are higher, the more the frost heave is higher; Meanwhile, with the decreased temperature, the frost heave will increase. However, when the temperature decreases to a specific value,the frost heave will stop mcreasmg.2. With the cement contents as5%, the fines contents as3%,5%,8%,12%respectively, the twelve sets of samples had been conducted the frost heave tests in situ under the conditions of different water mass fractions.the result shows that after the graded broken stones were mixed with cements, the frost heave of the graded broken stones had been depressed significantly.Meanwhile, with the increment of cements, its modulus of deformation had increased. After experienced50frozen-melting, the groups of sample with different added cements still met the demand of the track ride for the high-speed train running under the conditions of filling with water at the max frost heave. Taking into account of the economical efficiency and workability, it is suitable to add5%to7%cement.