Probabilistic Performance Analysis of Prefabricated Vertical Drains on Soft Soils

Abstract

Properties of soft soils largely influence their behavior and the design scheme of the ground improvement that would be required. The time for 90% consolidation could be estimated theoretically with time factor, coefficient of consolidation, compressibility and permeability. As the reproducibility of these tests is very less, estimating the properties accurately is highly challenging. Repeating the test also would usually result in obtaining a wide range of values. Since the ground improvement scheme is largely dependent on these properties, probabilistic tools and reliability-based design must be used. In soft soils, prefabricated vertical drains (PVDs) along with preloading is a popular method of increasing the bearing capacity of soils wherein the improvement is achieved by accelerating the consolidation process. The spatial and temporal variability of the soil properties affects the performance of the PVDs installed in the ground, and the same is investigated using probability distribution of the various properties used in the design of the ground improvement scheme. Monte Carlo simulations using the probability distribution and statistics of the design properties are used to capture the effect of variability of the design properties on the time for consolidation.