Composed of a raft and pipe piles with embedded heat exchange devices, a pipe-type energy piled raft foundation can enhance both foundation performance and energy utilization efficiency. An urgently needed thermomechanical analysis method would facilitate the optimization design and the broader adoption of this fundamental form. Therefore, this paper proposes an efficient method for the thermo-mechanical analysis of pipe-type energy piles with a raft in layered transversely isotropic media. The pile-soil and raft-soil interaction equations are derived by coupled finite and boundary element method. A simplified approach is then proposed and applied to tackle the pile-raft-soil coupling interaction. The correctness and efficiency of the method are verified through comparisons with a field test and two finite element numerical cases. Finally, parametric analyses are conducted to investigate the influences of temperature increment, pile thickness, raft thickness, and soil anisotropy on the performance of the pipe-type energy piled raft foundation.

In comparison with plant fibers, wool is under-exploited in composite applications. Coarse wool with >50 micron diameter is generally not preferred for apparel, blankets, or carpets and remains underutilized. In the reported work, non-textile grade coarse wool fabric was coated with vinyl ester resin (VER), and subsequently, composites were developed. To increase the mechanical properties of the composite, nano kaolinite was introduced as a filler. The effect of various concentrations (0.25, 0.50, 1.0 %) of nano kaolinite (NK) on the physico-mechanical and aging characteristics of the developed composites was investigated. The results inferred that a minor addition of nano kaolinite (0.5%) in the wool + VER composite resulted in an increase of 16% tensile strength, 31% modulus, and 19 % impact strength, respectively. The findings of the dynamic mechanical analysis showed that, with 0.5% nano kaolinite addition, the composite's storage and loss modulus were exhibited as 1.9 and 0.22 GPa, respectively, which are higher than those of the control wool + VER composites (1.1 and 0.15 GPa storage and loss modulus respectively). The SEM images depicted a moderate adhesion between the wool fiber and the vinyl ester resin. The presence of nano kaolinite in the composite results in a marginal reduction in the water contact angle and an increase in the water diffusion properties. The thermal and UV aging properties of the wool-vinyl ester composites were improved with the addition of nano kaolinite; however, the developed composites showed poor soil degradation.

The discrete element method (DEM) is used to simulate the behavior of a model sand under cyclic stress. Two approaches are employed in the contact model to account for the effect of anisotropic particle shape: (1) spheres with a rolling resistance moment and (2) clumps of spheres. Model parameters are calibrated using experimental results from drained monotonic triaxial tests on NE34 sand. Then, a series of cyclic triaxial tests is done on a homogeneous elementary volume sample with varying density index (ID\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$I_D$$\end{document}) and cyclic stress ratio (CSR). Both macroscopic and micromechanical characteristics of the material are examined under cyclic loads. In particular, the evolution of Young's modulus (E) and the damping ratio (D) with strain amplitude are evaluated at varying ID\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$I_D$$\end{document} and compared with values from the literature. An analysis of the coordination number (Z), orientation of strong and weak contact forces, friction mobilization, sliding contacts and fabric evolution links the observed macroscopic behavior of energy dissipation to the phenomenon of frictional sliding at the grain scale.

The study delves into the elastoplastic deformation of a frozen wall (FW) with an unrestricted advance height, initially articulated by S.S.Vyalov. It scrutinizes the stress and displacement fields within the FW induced by external loads across various boundary scenarios, notably focusing on the inception and propagation of a plastic deformation zone throughout the FW's thickness. This delineation of the plastic deformation zone aligns with the FW's state of equilibrium, for which S.S.Vyalov derived a formula for FW thickness based on the strength criterion. These findings serve as a pivotal launchpad for the shift from a one-dimensional (1D) to a two-dimensional (2D) exploration of FW system deformation with finite advance height. The numerical simulation of FW deformation employs FreeFEM++ software, adopting a 2D axisymmetric approach and exploring two design schemes with distinct boundary conditions at the FW cylinder's upper base. The initial scheme fixes both vertical and radial displacements at the upper base, while the latter applies a vertical load equivalent to the weight of overlying soil layers. Building upon the research outcomes, a refined version of S.S.Vyalov's formula emerges, integrating the Mohr - Coulomb strength criterion and introducing a novel parameter -the advance height. The study elucidates conditions across various soil layers wherein the ultimate advance height minimally impacts the calculated FW thickness. This enables the pragmatic utilization of S.S. Vyalov's classical formula for FW thickness computation, predicated on the strength criterion and assuming an unrestricted advance height.