Tytuł Data publikacji Autor
N/A
2020
Jakub Konkol,
Lech Bałachowski
W ostatnich latach rzadko wykonuje się pale wiercone o bardzo dużych średnicach ze względu na: wymagany sprzęt, transport wydobytego urobku gruntowego, duże ilości stali zbrojeniowej. Konstrukcje inżynierskie na autostradzie A-1, na drodze ekspresowej S-7 i Obwodnicy Południowej Gdańska posadowiono na palach prefabrykowanych. Fundamenty największych mostów na autostradzie A-1 zbudowano na palach Vibro i Franki. W artykule zwrócono uwagę na pale w pełni przemieszczeniowe, charakteryzujące się dużą nośnością uzyskiwaną w krótkim czasie od wykonania i prostą technologią, które są stosowane w fundamentach obiektów drogowych. Spośród wszystkich, obecnie wykonywanych rodzajów pali, tę technologię można nazwać ekologiczną i ekonomiczną. Te aspekty mogą zmienić zakres zastosowania pali przemieszczeniowych w najbliższej przyszłości.
2020
Paweł Więcławski,
Kazimierz Gwizdała
Flow in flood dikes, earth dams, and embankments occurs in variably saturated conditions, with pores of the earth material filled partly with water and partly with air. In routine engineering analysis, the influence of pore air is neglected and the air pressure is assumed equal to atmospheric. In some circumstances, for example, during overtopping of the dike by water, the effect of pore air on water flow and stability of the structure can be important. These features cannot be captured with the commonly used Richards equation. In this paper, we analyze earlier experiments on the overtopping of a model dike made of fine sand. During the experiments, a significant amount of air was trapped near the outer slope of the dike, which later escaped through a fracture formed in wet sand. The observations were compared with numerical simulations using the Richards equation and the two-phase immiscible flow model. The deformation and damage of the dike were not modelled, but the initial evolution of the entrapped air pressure (before damage occurred) was in a good agreement with two-phase flow simulations.
2019
Witold Tisler,
Wioletta Gorczewska-Langner,
Leśniewska Danuta,
Maciejewski Stanisław,
Rafał Ossowski,
Adam Szymkiewicz
This paper presents a critical analysis of some selected codes and practical recommendations used as basic rules in the design procedures of modern marine fender systems. The first part of the discussion pertains to the existing equations used in calculating the eccentricity coefficient in the ship’s kinetic energy equation and the maximum allowable fender pitch (spacing) in a set of fenders installed along a quay wall. A new approach for the single-fender ship-to-fender contact mode during the side-berthing procedure is introduced, assuming three different special cases (i.e., the prequarter-point case, the quarter-point case, and the postquarter-point case) of the relative position of the ship’s hull with respect to the compressed fender unit. New equations are proposed for the maximum allowable fender pitch and the extreme berthing angles associated with the postquarter-point case of the single-fender and two-fender contact modes. Taking a ferry contact with an MV-type (or pi-type) modular fender as an example, a detailed computational analysis has been performed, illustrating permissible geometrical ship-fender-quay configurations and their influence on the eccentricity coefficient, and, consequently, on the effective kinetic energy of a berthing ship.
2019
Waldemar Magda
Addressed here is the Particle Finite Element Method (PFEM) modelling of undrained CPTu penetration with regard to a reference analytical solution based on the Spherical Cavity Expansion Method (SCEM). Also discussed is the choice of the soil model and its parameters. The effect of cone interface friction on CPTu simulation is analyzed in a series of penetration tests using Arbitrary Lagrangian-Eulerian (ALE) and Updated Lagrangian (UL) methods. The results of the simulations are compared with the Authors’ proposal.
2019
Jakub Konkol,
Lech Bałachowski
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