Finite Element Analysis Of Reinforced Sand Cushion Strengthening Of Embankment On Soft Ground

With the development of highway construction in China, it is usually confronted with building embankment on soft grounds. Because the soft soil has a lot of characterisitics such as the low strength, high deformability and low permeability, so the soft grounds have to be treated with some kind of method so as to improve their engineering properties to meet the standard of constraction. In recent years, the practice and study has proved, in the condition of the soft soil layer is not thick and embankment is not high, using geosynthetics reinforced sand blankets to improve the performance of soft grouds is simple, speedy and economical. However, the reinforcement theory of reinforced sand blankets is not clear. The backwardness of the theory limits the application of the geosynthetics in practice.In this paper, the finit element analysis software ANSYS is used to calculate different embankments. One is non-reinforced embankment, one is only sand blankets, one is one layer of Geogrid reinforced sand blankets on the bottom of the embankment, and the other is two layer of Geogrid reinforced sand blankets on the bottom of the embankment. The displacement, stress and reinforcement tension results are analyzed. All the results enunciation: (l)The main function of the reinforced sand blankets is decrease lateral deformation of the embankments and the shallow layer soft grounds,the restraint of vertical settlement is not obviouse. (2)Because of the stress diffusivity, reinforced sand blankets decreased the differential settlement on the bottom of the embankment. (3)The reinforced sand blankets decreased shearing strength more effective than vertical stress.In this paper, the finit element analysis software is also used to calculate some main influence factors of the reinforcement effect,such as thickness of the soft groud, strength of the soft ground and modulus of the geosynthetics. All the results enunciation: (1) The thicker the soft soil layer is, the smaller the reinforcement effect is, and the reinforced sand blankets is not effective to treat thick soft ground. (2) Within a certain scope, the weaker the soft soil grounds is, the more obvious the reinforcement effect is. (3) Modulus of the geosynthetics have a reasonable scope, we should consider every factors synthetically in engineering practice, choosing a appropriate reinforced material.This paper analyzed the reinforcement effect and the reinforcement mechanism, which provids some reference values for design calculations and further research.