Study On The Consolidation Characteristics Of Layered Soils

Study on the consolidation characteristics of soil is one of basic tasks in soil mechanics. Soil is multi-phase and natural-historical, so it decides that the process of consolidation is complicated. During this process, water in the soil will be discharged accompany with void ratio decreasing, and the volume will be compressed and become smaller, the effective stress will increase, and shear strength be improved These characteristics of consolidation usually are used in engineering to improve bearing capacity and decrease settlement of foundation especially soft one.Layered soils are made of different attributes and thicknesses and components which were assembled according to some ways. Under long geologic effect, in situ stress, water, temperature and man-made effect, microcosmic damage and macrostructure were brought in soils, so their characteristics are very different from single soil. There are lots of layered-soils problem in design and construction of practical underground engineering such as foundation, road and slope. Instability and disaster of geotechnical engineering like differential settlement of foundation and sliding slope usually are encountered due to strength, deformation and breakage of layered soils. So there are theoretical and practical significance of this paper.The layered-soil ground of Du Jiangyan-Wen Chuan's expressway is engineering background of this paper. Firstly, according to Biot 2-D consolidation equation, author study the 2-D Biot consolidation problem using integral transform and matrix transfer. When lower boundary is rock, stress and displacement of any point in ground are got Then, combination geology analysis with laboratory test, some parameters of ground and filling of embankment are got Then, Adina which is a kind of FEA software is introduced simplely. Then, model of Finite Element is established by controlling the birth time of element to achieve to load step by step. The curve of settlement-time, pore pressure-time and Y-displacement-time are got. At last, contrasts with data from field were carried out, which were validated preferably.It was revealed by the research result that settlement of layered-soil ground most is down within embankment, whereabouts is up. Settlement and heave decrease with the depth increasing. From time settlement increase with time increasing, however heave become larger firstly and smaller lastly. The dissipation of pore pressure is slower within embankment and deeper position, and it is going along with time, but there is some fluctuation. Y-displacement is larger when deeper, and it is the largest near embankment from horizontal direction. From time it is the largest when load is over, and then decrease a little.