Red Sandstone Soil Weathering Effects Under Load Impact Action At Multiple Points

Red sandstone existed in large quantity in china, southern Jiangxi is a highly developed areaof it. Red sandstone is widely used in backfilling the foundation, Dynamic Compaction and otherimpaction load are all common methods to reinforce the foundation, specially for DynamicCompaction, it is getting more and more application because of its wide range of trial, significantstrengthening effect, deep effective reinforcement, simple construction machine, inconsumablevaluable materials even inconsumable any materials, low cost, and short construction period. Butthe theoretical study of the Dynamic Compaction and other impaction load for reinforcingfoundation is a little bit lag behind. Red sandstone is studying object in this article, we gain thefollowing conclusion after studying multipoint impact load’s effect of action and overlay effectunder red sandstone outside and inside.1,Under impact loading effect, the soil within the temper diameter of red sandstone mainlymove vertically, the soil out of the temper diameter of red sandstone mainly move horizontally.The vertical displacement and density first increase and then decrease with the enlarge of thedeep. The vertical displacement and density overlay effect in the temper centre enhance with theincreasing of strike and fall. Vertical displacement and density overlay effect decrease with theincrease of distance between the tamping points.2,With the increase of strike, the cohesive force and internal friction angle of the soil in thetemper center all increase. The overlay effect of shearing strength of soil weakens with theincrease of distance between the tamping points. Weaken degree is so obvious when thedistance between tamping points increase from3.5times hammer size to4times hammer size.The key factor for the strength of shearing of red sandstone is cohesive force.3,Two-point tamping, the density and effect of shearing strength is better when movevertically with3times track hammer in distance of the temper point,5.0cm in distance of tempercenter, and the density and effect of shearing strength is better when move vertically with12.0cmdeep distance of them than any other test. It is much better when move vertically with7.5cm indistance of temper center,4times track hammer in distance of the temper point than that with4.5times track hammer.4,Four-point tamping, when the distance of temper point is3,3.5,4,4.5times track hammer,the distance of temper center is7.5cm,8.75cm,10.0cm,11.25cm in sequence, however the densityand effect of shearing strength is best when move vertically with12.0cm deep distance of themand distance of temper point3.5times. The density and effect of shearing strength is obviouslybetter with distance of temper center12.0cm, move vertically, than that the distance of temperpoint are3and3.5times track hammer, the distance of temper center is5.0cm and the distance of temper point are4and4.5times track hammer, the distance of temper center is7.5cm. Overlayeffect of Shearing strength enhance with the increase of strike.5,After dynamic compaction reinforce to a project’s red sandstone filling ground with theparameter we tried out in this essay, the carrying capacity feature of foundation reach190kPaafter testing, project properties meet the design requirement.The related conclusion obtained in this essay will have a certain help for further research,design and construction of red sandstone fill ground dynamic reinforcement in Southern Jiangxi.