Large-Strain Radial Consolidation Model For Layered Soils

The deep soft clays are widely distributed in the coastal areas in China.The clayey soil cannot satisfy the requirement of any constructions.The surcharge preloading combined with vertical drains is commonly used to improve the bearing capacity of soft foundations.A large strain radial consolidation model for layered soils,called RCS2(Radial Consolidation Settlement 2)was developed in this research.The main contents studied in this thesis are as follows:(1)Based on the theory of soil consolidation,RCS2 model was developed and introduced from the aspects of model geometry,constitutive relationships,stress,pore pressure,flow,settlement,and time increment.(2)Consolidation of multi-layered soil with vertical and radial drainage was analyzed by RCS2 and compared with other analytical and numerical solutions.The accuracy of RCS2 was verified from the comparisons.(3)A parametric study was performed using RCS2 to investigate the effects of three influencing factors(i.e.,ratio of radial to vertical permeability coefficient,length of vertical drain,and the orders of soil layers)on the large strain radial consolidation.The simulated results indicated that the radial permeability coefficient has a greater influence on the consolidation than the vertical permeability coefficient.The soil penetrated by the vertical drains is mainly subjected to radial drainage.Longer vertical drains result in higher consolidation efficiency.The consolidation effect of soft soil is closely related to the orders of soil layers.The radial permeability coefficient of the bottom soil layer accelerated the consolidation of the lower soil layer when it was increased.The reason is that radial permeability coefficient plays a decisive role in radial consolidation of layered soil.(4)RCS2 was applied to ananlyze the Shenzhen-Hongkong Western Corridor project.The results calculated from RCS2 is in reasonable agreement with actual monitoring data.The RCS2 model has good accuracy in practice.In general,RCS2 is an effective model to predict the radial consolidation with consideration of non-linear constitutive model,large strain and multilayer of soil.This consolidation model can provide guidings for soil consolidation calculation for engineering practice.