Study On Deformation And Stability Characteristics Of Highway Embankment Slopes Reinforced With Geogrids

With the implementation of the development strategy of western areas in China,high-grade highways have been rapidly developed in mountainous areas. Due to complextopography in mountainous areas, the high embankment has become the major roadbedform. It is prone to instability and deformation of the embankment slope influenced by avariety of factors. The geogrid has good physical and mechanical properties, which canremarkably enhanced the overall stiffness of the soil, and effectively improve thedeformation characteristics of embankment slope. The overall performance of theembankment will be significantly enhanced. Therefore, geogrid has been widely appliedto many fields of engineering construction.In this thesis, the deformation and stability characteristics of high embankmentslope reinforced by geogrid were studied by using the finite-difference StrengthReduction Method with numerical analysis model based on FLAC3D.Firstly, a series of triaxial tests were conducted to study the stress-strain relationshipand the shear strength of reinforce soil with different geogrid layers and confiningpressure. The results show that, the peak strength of the samples with1and2geogridlayers increases by2.1%~8.1%and14.6%~17.1%, respectively; the soil sample hasremarkable ductility and strong late effect; the normalized intensity parameter quite bigunder the confining pressure for200,300kpa, which proves the rationality of thereinforce effect by geogrid.Afterwards, the present research analyzed the effect factors the geogrid reinforcedhigh embankment stability and geogrid reinforced, and then put forward reasonableproposals. The results show that, geogrid with the length of26~45m can effectivelyreduce the displacement of the toe of embankment slope, and improves the overallstability of the embankment. With the same mechanical parameters, geogrid with tensile modulus of50~200kN/m and7~9layers has the best reinforced effect. For theembankment with variable slope, the reinforce effect will be remarkable when thegeogrid is located in range of8-26m in the lower part of the slope.Finally, using the same layout mode of geogrid obtained by the numerical analysisof high embankment slope, the slope stability under the seismic loading and rainfallinfiltration was analyzed in the present study. Inhibition of geogrid reinforced sloperoadbed deformation and the overall stability of the embankment slope in Rainfallinfiltration and embankment seismic performance enhancements were validated by usingdifferent shear strength reduction.