This study builds up an elliptical cylindrical equivalent model (ECEM) of prefabricated vertical drains (PVD)‐improved foundation which incorporates the nonlinear variation of compressibility and permeability and the preconsolidate state of soil. An exact solution and a simplified solution are derived for the nonlinear consolidation model under a combined vacuum and surcharge preloading. Considering the stratification of improved soil and the reduction of vacuum pressure along PVD, a precise settlement prediction method is proposed. The rightness and applicability of present solutions are verified by carrying out a series of comparative analyses. Also, a parametric study is conducted to investigate the characteristics of nonlinear consolidation under different Nσ, Cnormalc/Cnormalk, over‐consolidation ratios (OCRs). The results show that, when Cnormalc/Cnormalk=1 the applied load has no impact on the dissipation of excess pore‐water pressure, whereas a larger applied load would induce a quicker settlement rate; the consolidation rate would be underestimated if the over‐consolidated stress history is neglected, and greater OCR produces more obvious underestimation.
Low strain integrity tests (LSITs) are the most popular non-destructive methods for pile testing. However, traditional LSITs have encountered unprecedented challenges as the need for long pile and existing pile testing keeps multiplying. Compared to traditional longitudinal excitations, the torsional wave is less influenced by the velocity attenuation effect and can be subjected at the pile shaft for existing piles. Distributed torsional LSIT is proposed in this article with the presentation of the corresponding analytical solutions that exhibiting the velocity responses along the pile shaft. The solution is verified with previous simplified theoretical and rigorous finite element method (FEM) answers. At the end, the application of this method is exhibited through the identification of necking and concrete segregation defects on pipe piles, which shows the advantage of this method on long pile testing.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.