Experimental and numerical study of the behavior of a stone column subject to the loading effect

The realization of engineering structures in compressible sites, requires in-depth geotechnical reconnaissance, as well as a study of the mechanical behavior of the soil, in order to adapt suitable soil improvement solutions. This is the case with the Annaba viaduct in Algeria, where it was found during the site survey that the soil is poor and very compressible. The foundations in these soils eventually pose the problem of their low bearing capacity and significant settlement. This, therefore, leads to the choice of reinforcement techniques. Among the many methods of improving soils, we have selected the stone column technique. The object of our article is to study the behavior of these columns, in terms of settlement and, through the loading tests on real site, we have found out that the intermediate columns are stiffer and more confined than the bank columns and the percentage reduction in settlements of these two types is important. Then, this experimental study is validated by the Plaxis 2D software, where the configurations are studied to find the best model that approximates the real behavior of the reinforced soil.

Effect of gait protocols and postoperative shoes on off-loading of forefoot in preoperative patients for forefoot disorders

ABSTRACT Objectives The purpose of this study was to clarify the effect of gait protocols and postoperative shoes on forefoot load in preoperative patients for forefoot disorders and compare footwear comfort between different types of postoperative shoes. Methods Fourteen subjects scheduled to undergo forefoot surgeries were recruited. The maximum force under the forefoot region was measured during 10 m straight walking in two gait patterns with six different shoe types. Visual analogue scale (VAS) scores for footwear comfort, subjective lower thigh pain, and electrical activities of lower thigh muscles were also evaluated. Results The body weight-normalized maximum force under the forefoot region significantly decreased in step-to gait compared to normal gait regardless of the shoe types used. Under the same gait condition, no significant difference was observed in the forefoot off-loading effect between the different shoe types used. Significantly worse VAS scores, significantly higher tibialis anterior muscle activities, and complaints of lower thigh pain were demonstrated in the gait with the reverse camber shoe. Conclusions Gait protocol of step-to gait had more forefoot off-loading effect than postoperative shoes. The forefoot off-loading effect did not differ among the postoperative shoes, suggesting that postoperative shoes can be selected with an emphasis on footwear comfort.

Economic Emission Load Dispatch Problem with Valve-Point Loading Using A Novel Quasi-Oppositional-Based Political Optimizer

In the present paper, a novel meta-heuristic algorithm, namely quasi-oppositional search-based political optimizer (QOPO), is proposed to solve a non-convex single and bi-objective economic and emission load dispatch problem (EELDP). In the proposed QOPO technique, an opposite estimate candidate solution is performed simultaneously on each candidate solution of the political optimizer to find a better solution of EELDP. In the bi-objective EELDP, QOPSO is applied to simultaneously minimize fuel costs and emissions by considering various constraints such as the valve-point loading effect (VPLE) and generator limits for a generation. The effectiveness of the proposed QOPO technique has been applied on three units, six units, 10-units, 11-units, 13-units, and 40-unit systems by considering the VPLE, transmission line losses, and generator limits. The results obtained using the proposed QOPO are compared with those obtained by other techniques reported in the literature. The relative results divulge that the proposed QOPO technique has a good exploration and exploitation capability to determine the optimal global solution compared to the other methods provided in the literature without violation of any constraints and bounded limits.