Vibratory Compaction And Settlement-Deformation Of Loess-high Fill Highway Embankment

The settlement of subgrade has a relationship to stress, strain, strength and stability of subgrade. With regard to the subgrade of highway and railway, it relates to fill velocity, compacting methods and the utilization of compacting machineries. In use of compacting machineries, the vibrating compactor has been mainly using to be compacted in domestic and foreign. Even though people study the road settlement in consolidation theory respect, but no still to research the soil mass settlement-deformation law of vibrating compacting and vibrating compacted. As engineering practice, selection and utilization of vibrating compaction machineries have closed connection with subgrade settlement. In compacting, the frequency and running speed of vibrating compaction machineries and the vibrating compaction time influence the consolidation deformation of subgrade. Therefore, correct master the relationship of vibrating compaction machineries and subgrade settlement deformation, can increase efficacy, and decrease energy consumption, and the subgrade settlement-deformation can be further decreased.First, based on the design theory of vibrating compactor, this paper mainly consider the vibrating compactor behavior, assume the compacted soil mass as elastic body and elastic-plastic solid, use engineering wave theory, obtain rigidity coefficients and resistance coefficients of soil mass under vibrating load, propagate equations of the elastic wave and elastic-plastic wave and its stress (displacement) response equations.Second, regard subgrade fill as unsaturated soil, based on unsaturated soil theory, derivate the unsaturated soil three-dimensional consolidation equation, and compose the unsaturated soil three-dimensional settlement-deformation procedure that can easy be used.Third, the consolidation numerical calculation of unsaturated soil demonstrate that, for unsaturated soil, after instantaneous load, its surface settlement contain distortion settlement (starting settlement) and soil mass consolidation settlement which caused by interstitial pressure dissipation of soil mass (primary pore air pressure), and the former is mainly deformation.Forth, it takes 69m high loess-high fill embankment as research medium, through centrifuge test and unsaturated soil three-dimensional numerical calculation, obtain: 1) After vibrating compaction by loess-high fill embankment under self-weight pressure, the subgrade settlement-deformation appear "sag", that is, max settlement lies in center road and shoulder settlement are min, and l/3~2/3 of embankment high appear outward "extrusion" tendency; 2) Stress and displacement have same change tendency, that is, stress change tendency is inward and downward increasing, max shear stress lies in slope toe, definite depth of foundation and slope toe connected to foundation.Fifth, proceed from the relationship vibrating roller and soil mass consolidation deformation, obtain that: 1) From property, the compactive effort of vibrating roller is better, productivity is higher, compactive region is bigger, uniform compaction, better stability, small settlement deformation and widely used than static roller who have the same quality; 2) "vibrating velocity and vibrating compactor pass which have the intently relationship with soil mass compaction degree; 3) At the soil mass vibrating compacting, suitable increase the tonnage of vibrating roller can beneficial to the vibrating compaction of soil mass; 4) Suitable increase the frequency or amplitude of vibrating roller can heighten vibrating depth, increase compactive effort, generally, the vibrating frequency field is 30~45Hz.Final, based on the centrifuge test and unsaturated soil three-dimensional numerical calculation, obtain the relationship law between vibrating compaction and the settlement-deformation of loess-high fill embankment, and mainly consider the vibrating compaction that, advance the suggestions and measures of special handle for high embankment of stress and displacement which have fierce change, as enhance soil mass compac...