Under The Action Of Impact Laboratory Test Research Of Saturated Soil Properties

Dynamic compaction has been invented by French engineer L.Menard in1969,it wasattracted by the world with its remarkable effect, simple equipment, convenient construction,applicable range, economic and feasible,save material and other advantages, dynamiccompaction was regarded as one way of the most economical and the most common treatment fordeep foundation. In contrast, the theory of dynamic compaction was researched superficially.quantitative estimation for degree of improvement was nearly blank, The design and calculationof dynamic compaction was still relied on experience highly.Dynamic compaction indoor test has an important role in researching dynamic properrties ofsoil, deepening dynamic consolidation mechanism understanding, perfecting the design andcalculation method of dynamic compaction. Predecessors have undertaken severl indoor impacttests, these tests focused to establish stress-strain relations at undrained impact, providingconstitutive relation for dynamic compaction numerical analysis, but the investigation about thedynamic response to impact and reconsolidation behavior after impact under different drainageconditions for saturated soils of different permeability were very little.Based on this condition, the paper combined with some research content from the NationalNatural Science Fund "consolidation effect the dynamic consolidation improvement effectevaluation based on ground deformation", through a large number of previous research results,automatic triaxial apparatus was refited. impacting test and reconsolidation test after impact wereconducted on three kinds of different permeability saturated soil with different drainage conditionand impact energy under triaxial condition, the dynamic response under impacting and thecharacteristic during reconsolidation were researched. The relaionship between pore waterpressure, axial strain, drainage, volume change and impact energy, impact number underimpacting and reconsolidation was discussed, the different characteristic of three kinds ofdifferent permeability saturated soil under impacting and reconsolidation was camparativeanalysied. The research results could deep the knowledge about properties of soil duringimpacting and reconsolidation, improve the study on mechanism of dynamic compaction.