The Effect Of Cyclic Dry-wet Process On The Dynamic Behavior Of Cement-Soil

With the development of economy and society, high-speed railway and heavily loadedrailway will be the mainstream in the construction of railway. So filling materials ofsubgrade-soil become very important. But there are lack of subgrade-soil which aresuitable to design demand along the railway, it is very expensive that soil in site arereplaced by soil which are suitable to design demand through transportation from the otherplace. The effective solution is to improve the soil. Dynamic properties are important forthe improved soil because it is used under the cyclic load of train. The change ofenvironment will affect the dynamic behavior of subgrade-soil and be the reason of failureof subgrade at last. In this dissertation, the following work will be carried out.Firstly, the effect of dry-wet process on the cyclic fatigue strength is studied. We simulatemulti-situation of environmental change in the laboratory and measure the cyclic fatiguestrength under different situation. The correlation of number of dry-wet process anddescend of cyclic fatigue strength is derived by comparing and analyzing of test results.Secondly, the relationship between dry-wet process and the deformation of improved soilis mainly studied according to the reality of subgrade-soil. The correlation between plasticstrain and elastic strain of improved soil and dry-wet process is derived by the dynamictriaxial test.Finally, the dynamic modulus and damp of cement-soil are discussed. This can support thecalculation of the deformation of subgrade.