| There is still few analysis and study about the compaction effect to quanlity characteristic ,most of them are definition study. In the thesis ,on the basic of other people achievement we carry out study from those angles:We have completed 8 experimental study of loadings, partial inundating test, large area inundating test and great deal of test of soil characteristic. We summarized their effect and rule from improvement foundation. Through different centre distance of pole ,differen improvement width, depth and different filled soils ,comparing to one pile and more piles, pile themselves and pile between, and pile surrounding compaction soii affecting, natural condition compressing ,partial inundating, large area inundating three phase tests, exterinal loading collapsibility, themselves gravity collapsible external loading and gravity commonly affecting tests. We can conclude the affect and rule from compacting foundation in density degree,collapsible compress, bearing capacity ,precluding water and preventing filter and precluding water ect.When(?)ry unit weight of soil were more than 85% of the maximum,coefficient of collapsibility less than 0.015,initial pressure of collapsibility no less than 200kPa.Wh(?)ry unit weight of soil more than 80% of the maximum,in the 100kPa pressure,coefficient of collapsibility usually less than 0.015,initial pressure of collapsibility also more than 100kPa.When centre distance of piles were less than 2.25d,average dry unit weight of three pile soils usually close or more than 85% of the maximum , on this condition compacting ground will not collapse in the 200kPa pressure and inundating .When centre distance of piles were less than 2.75d,average dry unit weight of three pile soils usually close or more than 80%, compacting ground will not collapse in the 100kPa pressure and inundating.When damp of soil is suitable ,its dry unit weight of soil close or more than 84% of the maximum and dry unit weight of saturation soil close or more than 88% of the maximum ,under this conditions ,soil usually represent lower compressibility. coefficient of compressibility usually less than 0.2MPa-1,compression modulus more than 10MPa,this soil with compaction degree increase, the trend of compress decline keep a stable phase.When dry unit weight less than 79% of the maximum and dry unit weight of saturation soil less than 84% of the maximum soil usually represent higher compressibility.Coefficient of compressibility usually more than 0.5MPa-1, compressibility modulus less than 4MPa,this soil compressibilityincrease change is very slowly ,with the compaction decline.Between two condition soil ,its compressibility change greatly ,with the compaction increasing ,the trend of compressibility evidently decreasing.When centre distance of piles less than 2d,average compaction coefficient more than 0.97,minimum compaction coefficient more than 0.88,all of point soil of piles in any damp,compressing coefficient from 10～20MPa-1 to lower than 0.2 MPa-1.Settlement quantity of nature ground from 12cm to 0.4～1.6cm in the 200kPa pressure ,pressure ground bearing capacity increasing 2 times from 100kPa to 200kPa .Centre distance of pile less than 2.5d ,average compaction coefficient more than 0.87,minimum compaction coefficient more than 0.82 ,in the near of heartbeat of basic monad,most of compressing coefficient in the nature damp less than 0.2MPa-1,in the saturation less than 0.4MPa-1,besides partial in the nature damp range from 0.2 MPa-1 to 0.4MPa-1 ,in the saturation between 0.4MPa-1 and 1MPa-1.Settlement of compaction ground less than 2cm.Bearing capacity will improve to 150 200kPa,compared to nature ground increase by 50～100%.When centre distance of pile less than 2.25d,dry unit weight of soil more than 87% of the maximum or void ratio less than 0.89,water hardly have permeability through soil .When dry unit weight of soil more than 94% of the maximum or void ratio less than 0.7,it become no permeability water,in the compaction ground ,fully compacting region and I district of effective compacting region were hardly or cann't permeability water.
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