Experimental Study On Consolidation Deformation Characteristics Of Compacted Loess In Guanzhong Area

With the promotion and implementation of various strategic measures to develop the western region,a large number of loess engineering problems have been involved in the urbanization construction projects in Guanzhong region.Only by clarifying the consolidation deformation law of loess,can the post-construction settlement of the building be predicted correctly and the stability of the slope be analyzed effectively.Therefore,it is of great significance to study the consolidation deformation characteristics of compacted loess for predicting post-construction settlement and preventing engineering problems caused by creep in engineering construction.Based on a large number of literature,and after investigating the actual situation of loess in Guanzhong area,the soil selected from a construction site in Chang ’an District of Xi ’an.The basic physical property index of the soil sample was obtained after the basic physical property index test.Under the conditions of different water content,different compaction degrees and different vertical loads,indoor one-dimensional consolidation creep tests were carried out on the compacted loess.The stress and strain and time relation curve,stress and strain isochron curve and compression curve were obtained.Then the relationship between physical and mechanical parameters and deformation of compacted loess was analyzed,and the creep characteristics of one-dimensional consolidation of compacted loess were discussed.Through experimental research and theoretical analysis,it is found that under different water content and compaction degree,the stress-strain variation trend of compacted loess at different stress levels is basically the same,which has two deformation stages: initial creep and constant velocity creep.Water content and degree of compaction have great influence on the one-dimensional consolidation creep deformation of compacted loess.When the water content is higher or the compaction degree is smaller,the soil deformation is larger.When the water content is small,the stress-strain isochron curve of the compacted loess has no obvious yield point,and the soil deformation increases with the increase of the load.When the water content is 25%,the soil deformation shows obvious non-linearity.Under different water content conditions,the vertical stress of soil samples increases,and the porosity ratio decreases,and has a linear variation with the logarithm of the vertical stress.The higher the water content is,the worse the compressibility of soil samples is.With the increase of water content and vertical stress,the secondary consolidation coefficient increases.When the vertical stress is small,the increase trend of secondary consolidation coefficient is not obvious with the increase of water content.Based on the results of one-dimensional consolidation creep test in laboratory,the relationship between consolidation deformation and water content,degree of compaction and vertical stress was analyzed,and the boundary point of primary and secondary consolidation of compacted loess was determined to be about 40 min.The empirical formula is obtained by analyzing the ln(?/t)-ln(t)curve of compacted loess,and various parameters were determined.By fitting with the experimental results,it is found that the calculated values were consistent with the experimental values to a certain extent,and the one-dimensional empirical model of consolidation creep under different compaction degrees and different vertical stresses is obtained.The model has few parameters,is easy to determine,convenient and intuitive,and is easy to use.To a certain extent,it can reflect the one-dimensional consolidation creep characteristics of the compacted loess in Guanzhong area.