Unidirectional Consolidation To Resolve Complex Situations Under Continuous Boundary Conditions

The consolidation of the soil is one of the important problems in soil mechanics.Therein, the primary problem to be solved is the dissipation of the pore pressurevarying with time and space. To understand and control the distribution of porepressure with the change of time and space, we can intuitively know theconsolidation process of soil and soil’s degeneration law. Then, according to the rateof deformation, we can estimate the settlement regularity of structures well. Inpractical engineering, especially in the road engineering, the accurate predictionof sedimentation is very important.Terzaghi’s unidirectional consolidation theory is based on his assumption. Inpractice, this theory has been used very well. Later scholars launched tostudy deeper on the theoretical foundation that he set up. On the Terzaghi’sunidirectional consolidation theory, Gibson gave a series of analytical solution aboutthe unidirectional consolidation on the complicated situation of practical engineering,which had certain practical significance.In the theory of Terzaghi and later scholars’s, soil consolidation has somelimitations in the practical engineering problems. For the problem of the limitation,Guoxiong Mei transformed the drainage boundary in Terzaghi’s consolidationproblem and put forward to his new continuous boundary theory. And then he deriveand examined the continuous boundary, which was closed to the actual problems inEngineering.In this thesis, by using the continuous drainage boundary conditions, we analysethree kinds of comples unidirectional consolidation, and derived and examined thecomplex situations. The main research work:(1)As for the thickness of soil layer changing with time, many scholars discussthe unidirectional consolidation’s boundary problems with Terzaghi’s theory. But formany practical engineering, the continuous boundary condition is closer to the actualsituation. When studying unidirectional consolidation on soil thickness changing withtime, we divide it into single drainage and double-sided asymmetric and discuss themon the continuous boundary conditions. At last, we derive and get its analyticalsolutions.(2)In the unidirectional consolidation problem, one of the complex situations isexternal load changing with time. In the analysis of this complicated situation, we also use the continuous boundary conditions, and discuss the problems on two parts:construction stage and completion stage. We study the two problems, derive and getthe analytical solutions.(3)The Nishihara model is widely used on studying soft soil properties. Based onthe improved Nishihara model, we use the continuous boundary conditions and the‘Laplace’ transform, and get its unidirectional consolidation. Then we derve and getthe analytical solution.In this thesis, the analytical solutions are theoretical solutions. These can providesome valuable reference to the theoretical research of consolidation theory.