The Theoretical And Experimental Research On The Consolidation-Collapse Properties Of The Northeast Black Soil Based On Burland Model

The black soil of northeast China has complicate engineering properties,with the hard property,the well particle size,and the high compressibility.It is rare that research on the compressibility of the black soil of northeast China,and some experimental results and engineering projects showed the collapsibility of black earth.Therefore,this paper co MPared with the laboratory test and theoretical analysis,for research the compression,consolidation,and collapse properties of the black soil of northeast China,and modified the Burland intrinsic compression model and built a collapse model to research the influence of collapse.The main research result as follows:（1）the compressibility and collapsibility of the black earth with different organic and water content have been analyzed,and the consequence showed that water and organic content influence the a_v1-2,C_C,and C_V.The improvement of organic and water content can improve the compressibility of black soil,and the influence of water is most obviously.The improvement of organic content,water content and stress can reduce the consolidation coefficient and improve the consolidation time.The strong water-absorbing ability,decrease of void ratio,and stress history can influence the consolidation consequence.（2）There have three phases of compression-consolidation process:compression S1,transient collapse S2,and collapse S3.For organic content of 9%to 20%,the improvement of consolidation stress makes the phase S2 improved first and then decrease.The samples with organic content of 30%to 50%have no significant phase S2 basically,and the phase S3 shows stable with the improvement of organic content and stress,and the phase S3 just like a continue process of S1.The collapse coefficient shows that the obviously collapse at 25k Pa of organic content of 9%to 20%,and samples have the climax collapse at 100k Pa.The collapse coefficient has not arrived at 0.015 basically for organic content of 30%to 50%.The consolidation-collapse stability coefficient increased with organic content and stress.Mechanism analysis of consolidation-collapse of the black earth made by three part:organic matter can solve by water,consistence limit after collapse and tightness of soil.（3）Based on Burland intrinsic compression theory,a modified model had been built on suiting for black soil,and the work range of modified model has enlarged at 0.3 to 2.0 times liquid limit and5%to 85.36%organic content.Besides,a collapse model had been built to mirror collapsibility.according to multiple linear regression analysis,predicted the void ratio of compression and collapse process.