Investigation on the seismic response of geogrid reinforced soil walls backfilled with cement-fiber-treated soil through 1-g shaking table tests

Improving the characteristics of local low-strength soils at the construction site is one of the appropriate approaches to employ the soils as a backfill of geogrid reinforced soil (GRS) walls. In this study, the fiber-cement-treated sand-silt mixture was used as the backfill of walls. The post-earthquake performance of the walls was evaluated by applying the sinusoidal waves on 1-m high reduced-scale physical models and conducting a series of 1-g shaking table tests. A comparison of the wall models constructed with treated and untreated backfill indicated the advantages of geogrid-reinforced fiber-cement-treated soil walls subjected to strong ground motion. The results revealed the better behavior of the wall models backfilled with treated soil mixtures under dynamic loading. Such improved performance was more evident in (1) deformation responses, including the lateral displacement of wall facing, deformation mode, failure surfaces, and settlement of backfill surface and (2) acceleration response in different locations, including facing, reinforced, and retained zone of walls.

Scientific multi-agent reinforcement learning for wall-models of turbulent flows

The predictive capabilities of turbulent flow simulations, critical for aerodynamic design and weather prediction, hinge on the choice of turbulence models. The abundance of data from experiments and simulations and the advent of machine learning have provided a boost to these modeling efforts. However, simulations of turbulent flows remain hindered by the inability of heuristics and supervised learning to model the near-wall dynamics. We address this challenge by introducing scientific multi-agent reinforcement learning (SciMARL) for the discovery of wall models for large-eddy simulations (LES). In SciMARL, discretization points act also as cooperating agents that learn to supply the LES closure model. The agents self-learn using limited data and generalise to extreme Reynolds numbers and previously unseen geometries. The present simulations reduce by several orders of magnitude the computational cost over fully-resolved simulations, while reproducing key flow quantities. We believe that SciMARL creates new capabilities for the simulation of turbulent flows.

Experimental study on the behavior of MSE wall having full-height rigid facing and segmental panel-type wall facing

The amount of the lateral displacements on the mechanically stabilized earth (MSE) wall depends on the reinforcement extensibility and length, reinforcement-to-facing connection, and the wall facing, among others. In this study, the deformation behavior of MSE wall models was focused considering two types of wall facing and three types of reinforcement. A series of small-scale model tests were undertaken on the MSE wall having a full-height rigid (FHR) facing and a segmental panel-type (SPT) wall facing. At the same time, the models were using discrete geogrids, geosynthetic strips, and steel rods as reinforcement. The results showed that the geogrids-reinforced MSE wall with FHR facing exhibited the highest load capacity with the least vertical displacements. The MSE wall models with steel reinforcements generally exhibited the least lateral displacements at wall facing than those with geosynthetics reinforcements. Finally, the results showed that MSE wall models with FHR facing have generally lesser lateral displacements at the wall facing compared to those with SPT wall facing.

Biocasting of an Elastin-Like Recombinamer and Collagen Bi-Layered Model of the Tunica Adventitia and External Elastic Lamina of the Vascular Wall

The development of vascular wall models will foster the development of preventive and therapeutic therapies for treating cardiovascular diseases. However, the physical and biological complexity of vascular tissue represents a...

An experimental study of the bearing capacity of wall models with openings under one and two-way loading

The results of an experimental and numerical studies of the stress-strain state of wall models under one and two way action are presented. The mechanisms of destruction of walls with openings are described. The functional dependencies between the destructive loads of the onset of crack formation and the influencing parameters are obtained. It is shown that the openings are stress concentrators, leading to the occurrence of micro and macro damage, the appearance and development of cracks, and in some cases to the loss of stability of structures (walls). The obtained influence functions can be included in traditional calculation methods with the aim of clarifying them. The factors affecting the process of cracking and fracture are given. Their modeling will allow to predict and prevent adverse events. Practical methods for regulating stresses, forces, and displacements that reduce the influence of various concentrators are considered. The analysis of the destruction mechanism of wall models carried out in this article allows one to study the influence of the size, position, and shape of window openings on the bearing capacity of walls. For example, the presence of stress concentrations in the region of the corners of square openings and their absence in round ones. The system of indicators of the sentry type ICh-10 made it possible to control the deformation of models from the plane of the walls, which is especially important under conditions of lateral pinching. The experimental values of the strength of the walls with openings compared with the calculated ones, which made it possible to see the degree of simplification of the classical calculation models used in design practice.