In this study, three-dimensional numerical analysis has been performed to comprehend the time-dependent behavior of large piled rafts founded in saturated clayey soil, explicitly for the time of superstructure construction and post-construction up to the end of soil consolidation. The performance under different construction times for the corresponding unpiled raft and the piled raft with uniform pile length configuration of varying pile number, spacing, and length have been examined and then compared with that of non-uniform length configuration for the same total pile length. The dissipation of excess pore water pressure, average settlement, and differential settlement are presented and discussed in detail. A quicker dissipation rate of excess pore pressure is noted with either fewer piles, wider pile spacing, or shorter-length piles. An increase in construction time results in a lesser total average settlement at the end of consolidation. The piled raft with uniform pile length configuration shows a higher differential settlement than the unpiled raft. However, by adopting a suitable nonuniform length configuration, negligible differential settlement, higher load-carrying capacity, and a significant reduction in pile material volume can be achieved. Predictive expressions have been proposed to estimate the average and differential settlements of piled raft with uniform length configuration.

A novel method for predicting the load-settlement response of a single pile in sands is developed based on an interface constitutive model. Firstly, a rigorous nonlinear load-transfer model for the pile-soil interface is derived from the soil-structure interface constitutive model. This model incorporates the beneficial features of the adopted interface constitutive model and effectively simulates fundamental interface characteristics, such as strain hardening (or softening), normal shear dilation, and stress path dependency occurring at the pile-soil interface. Additionally, a hyperbolic load-transfer model is employed to simulate the nonlinear stress-displacement relationship between the pile end and soil. The parameters for the aforementioned load-transfer model can be calibrated through experimental interface shear tests and geotechnical experiments. Subsequently, a one-dimensional computational model for analyzing the load-settlement response of a single pile is proposed based on the load transfer method, with numerical solutions obtained using an iterative algorithm. Finally, the theoretical results are compared with reported and independently conducted model pile tests to validate the accuracy of the proposed theoretical approach. The experimental results show a good agreement between the predicted and measured values, demonstrating the method's excellent capability in predicting the load-settlement response of both displacement and non-displacement piles. This paper presents an analytical framework based on the interface constitutive model for analyzing the load-settlement response of single piles, providing a theoretical reference for optimizing the design of pile foundations in sandy soils under vertical loads.

Progress in jet grouting technology has been focused on the cutting-edge observer of jets, which aims to generate large columns of jet grouting and increase the activity of construction sites. Since jet grouting techniques vary from conventional grouting methods to modern techniques, they can be used in a variety of soil types and their application areas are expanding quickly. So, grouting methods have become very popular methods for subsoil strengthening. This article includes finding the physical and mechanical properties of the soil of the AL-Rashdia site, using a single-jet grouting machine and a steel model to test concrete piles and jet piles, and a double-jet grouting machine to compare the results obtained from laboratory model of one-dimensional jet grouting column pile with those of a one-dimensional concrete pile. The comparison showed that the settlement of the jet pile was smaller than that of the concrete pile and the bearing load was higher with jet columns giving a high bearing capacity comparable with the concrete pile. Shen's method is more adequate to find the ultimate bearing load and the settlement for this load. Also, the ultimate pile ratio was 115.63% for the jet column, and the ultimate pile ratio for the concrete column was 123.49%. The compressive strength of the core sample of jet columns was large which improved the bearing capacity of the foundation.