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Lech Bałachowski

Abstract

The physical modelling of subsoil behaviour and soil-structure interaction is essential for the proper design of offshore structures and port infrastructure. A brief introduction to such modelling of geoengineering problems is presented and some methods and experimental devices are described. The relationships between modelling scales are given. Some examples of penetration testing results in centrifuge and calibration chamber are presented. Prospects for physical modelling in geotechnics are also described.

Open access

Katarzyna Białek and Lech Bałachowski

Abstract

Bearing capacity of the working platform for heavy tracks was analysed using Distinct Layout Optimization (DLO) method. The platform layer constructed from cohesionless soils is resting on weak cohesive subgrade. Different thickness of the platform, its effective angle of internal friction and undrained shear strength of the soft soil were taken into consideration. Kinematic method permits different failure mechanisms to be analyzed. Margin of safety for a given load and subsoil conditions was determined using two approaches: increasing the load or decreasing the shear strength up to failure. The results were compared with solution proposed in BRE recommendations.

Open access

Lech Bałachowski and Zbigniew Sikora

Abstract

Bottom ash from EC Gdańsk and dredged material taken from the mouth of The Vistula were mixed to form an engineering material used for dike construction. Mixtures with different bottom ash content were tested in laboratory to determine its basic physical and mechanical properties. The optimum bottom ash-dredged material mixture, built in the corps of the test dike, contains 70% of ash. The optimum bottom ash content in the mixture was chosen taking into account high internal friction angle, good compaction and reduced filtration coefficient. The maximum dry density of the mixtures was measured in Proctor test for the mixtures formed in laboratory and on samples taken from the test dike. Minimum and maximum void ratio were also determined.

Open access

Jakub Konkol and Lech Bałachowski

Abstract

In this paper, a numerical undrained analysis of pile jacking into the subsoil using Abaqus software suit has been presented. Two different approaches, including traditional Finite Element Method (FEM) and Arbitrary Lagrangian–Eulerian (ALE) formulation, were tested. In the first method, the soil was modelled as a two-phase medium and effective stress analysis was performed. In the second one (ALE), a single-phase medium was assumed and total stress analysis was carried out. The fitting between effective stress parameters and total stress parameters has been presented and both solutions have been compared. The results, discussion and verification of numerical analyzes have been introduced. Possible applications and limitations of large deformation modelling techniques have been explained.

Open access

Lech Bałachowski and Norbert Kurek

Abstract

Vibroflotation, vibratory compaction, micro-blasting or heavy tamping are typical improvement methods for the cohesionless deposits of high thickness. The complex mechanism of deep soil compaction is related to void ratio decrease with grain rearrangements, lateral stress increase, prestressing effect of certain number of load cycles, water pressure dissipation, aging and other effects. Calibration chamber based interpretation of CPTU/DMT can be used to take into account vertical and horizontal stress and void ratio effects. Some examples of interpretation of soundings in pre-treated and compacted sands are given. Some acceptance criteria for compaction control are discussed. The improvement factors are analysed including the normalised approach based on the soil behaviour type index.

Open access

Jakub Konkol and Lech Bałachowski

Abstract

In this paper, the whole process of pile construction and performance during loading is modelled via large deformation finite element methods such as Coupled Eulerian Lagrangian (CEL) and Updated Lagrangian (UL). Numerical study consists of installation process, consolidation phase and following pile static load test (SLT). The Poznań site is chosen as the reference location for the numerical analysis, where series of pile SLTs have been performed in highly overconsolidated clay (OCR ≈ 12). The results of numerical analysis are compared with corresponding field tests and with so-called “wish-in-place” numerical model of pile, where no installation effects are taken into account. The advantages of using large deformation numerical analysis are presented and its application to the pile designing is shown.