Study On The Physical And Mechanical Characteristics Of Lacustrine Sedimentary Soft Soils In Changzhou Area

Taking the lacustrine sedimentary soft soils in Changzhou area as the research object,this paper presents a systematic investigation on the physical and mechanical characteristics of lacustrine soft soils in a given national highway project of roadbed widening and reconstruction in Changzhou area through laboratory tests,theoretical analysis and numerical simulation.Main conclusions are summarized as below:1.The topographic features,soil composition and distribution in Changzhou area are analyzed and summarized.Based on the advanced test equipment of a geotechnical laboratory in a survey unit in Changzhou City,the physical parameters such as water content,gravity,liquid and plastic limit are obtained.These physical parameters were analyzed by statistical regression analysis method and compared with the in situ measurement results.The normalized data which can reliably reflect the actual situation are obtained..2.Based on the triaxial apparatus in geotechnical laboratory of Changzhou survey and mapping institute,the mechanics parameters of lacustrine sedimentary soft soil are studied.The drainage and consolidation characteristics of lacustrine sedimentary soft soils under different loading conditions and confining pressures are analyzed by means of laboratory tests.The effects of confining pressures and loads on the drainage,volume strain and volume strain rate of soft soil are discussed and the corresponding conclusions are drawn.The variation of void ratio of soil samples with different depths under triaxial compression is discussed,and the effect of depth on the void ratio of lacustrine sedimentary soft soils is discussed.Based on the statistics and processing of triaxial UU shear test data,the comprehensive curve of shear strength versus deformation of lacustrine sedimentary soft soils is fitted.3.Based on ABAQUS finite element software,the finite element model of lacustrine soft soil of is established.Its deformation characteristics under load are analyzed by means of numerical simulation and the results are compared with those obtained by theoretical analysis method.Referring to the settlement monitoring data of similar buildings in Changzhou area andcombining with BP neural network method,the settlement and deformation of the roadbed widening and reconstruction project site in Changzhou section of a national highway are predicted.Finally,by comparing with the field measured data,it is found that the coincidence degree of the three is high,which indicates that the physical and mechanical indexes of the lacustrine sedimentary soft soils obtained by the geotechnical test method are in line with the actual situation.The data and applicability are verified.The results have certain reference value for similar site construction activities in Changzhou area.