Experimental and numerical analyses of lightweight foamed concrete as filler for widening embankment

Abstract In order to control the differential settlement between the existing and widened embankments, lightweight foamed concrete (LWFC) was proposed as a filler of the widened embankment to decrease its self-weight. A series of compressive strength tests, dynamic triaxial tests, dry–wet cycle tests, and water immersion tests were performed to analyze the variation of the LWFC strength with design dry density and the influence of water and adding glass fiber (GF) on the properties of the LWFC. Then two centrifugal models of the widened embankment, which was filled with the LWFC and traditional soil respectively, and their numerical models were established in this study. The results show that water adversely affects the LWFC strength. A lower density for LWFC is corresponded by greater compressive strength loss after the LWFC underwent 15 dry–wet cycles. When the LWFC with a design dry density of 300–800 kg/m3 was immersed in dead water, the compressive strength and dynamic stress threshold ratios of the LWFC decrease quickly at first and then increases slightly with increasing soaking days. While the LWFC was immersed in live water, these parameters gradually stabilize for a design dry density of no less than 600 kg/m3 and decrease for a design dry density of less than 500 kg/m3 with increasing soaking days. Mixing GF into the LWFC can significantly improve the compressive strength and dynamic stress threshold and reduce the influence of water. Furthermore, the use of the LWFC as a filler of the widened embankment can significantly decrease the settlement of the embankment surface, soil pressure on the foundation surface, and horizontal deformation of the foundation compared to the traditional soil used as filler for widening embankment.