Numerical Simulation Of Mechanical Behavior Of Widening Highway Embankment In Mountain Area Based On The Soil-structure Interaction

For the widening highway embankment in mountain area, the crucial is to control differential settlement at the top of the new and old roadbed and guarantee the subgrade stability.Around the project goals, the numerical simulation of the mechanical behavior of widening highway embankment in mountain area based on the soil-structure interaction and engineering treatment measures study was carried out.The retaining structures, including the balance weight retaining wall were set up outside the new embankment unilaterally in mountain region highway embankment widening reconstruction. The finite element software Phase2 was used to build a detailed numerical model for describing the interaction between soil-wall, which introducing the joint element. Based on two-step approach, the nonzero displacement constraints were imposed on metope to simulate the retaining wall trarislational and rotational (RBT) active extraversion deflection. The effect of the retaining wall’s different deformation amount of active extraversion deflection on the embankment differential settlement was analyzed. The results were testified and compared with the geotechnical centrifuge model test results. It shows that the rigid retaining wall and the new and old embankment are interaction and interdependence. Additional differential settlement, which caused by retaining wall’s active extraversion deflection, is 51%～67% of total differential settlement when the ratio of the extraversion value and wall height is 1%～3%.Combined with the particularity of the rigid retaining wall of widening highway embankment in mountain area,the finite element software Phase2 and strength reduction method are used to carry out the numerical simulation of reinforce stability of widening highway embankment in mountain area,which introducing the joint,structural interface unit.Exploring the dynamic evolution law of the filled soil,geogrid, soil-geogrid interaction and the influence to the embankment stability.The results were testified by the geotechnical centrifuge model test results. It shows that geogrid can reduce the settlement of the roadbed surface, limite wall extraversion, strengthen roadbed stability. The influence weightiness to the roadbed stability, which comes from the filled soil, geogrid and soil-geogrid interface, is dynamic changing. With the increase of SRF, soil-geogrid interface unit will slip failure, but not play a decisive role for the subgrade stability. The upper level Geogrid that outside the edge of balancing platform is pulled, and the axial tension decreased, leading to the failure of widening highway embankment.Combined with the practical experience on widening highway embankment engineering in our country and related research, the basic technical thought of engineering countermeasure in mountain region highway embankment widening reconstruction are put forward.At the same time, summarizing the engineering treatment measures of controlling the embankment differential settlement and stability. Such as embankment reinforced, set up the steps in the new and old roadbed joint, filling selection and compaction process controling, half road and half bridge structure setting, retaining wall setting, foundation treatment, slope protection etc.