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Investigation of changes dynamics in the settlement properties of foundation soils by construction of soil piles using a vibratory loader


Author: Râșcovoi Alexandru
Degree:doctor of engineering
Speciality: 05.23.05 - Building Materials and Elements of Construction
Year:2019
Scientific adviser: Vladimir Polcanov
doctor, associate professor (docent)
Institution: Technical University of Moldova

Status

Term of presenting of the thesis 29 March, 2019

Abstract

Adobe PDF document2.67 Mb / in romanian

Thesis

CZU 624.131

Adobe PDF document 12.99 Mb / in russian
185 pages


Keywords

settlement, settlement sensit ive soil, eliminat ion of settlement, physicomechanical properties, microstructure, soil piles, vibrator

Summary

Specialty: 211.02 – Construction materials, elements and edifices Thesis structure: introduction, three chapters, conclusions and recommendations, references (180 tit les). The content is presented on 118 basic text pages, 12 tables (without appendices), 49 figures and 10 appendices. Research results are published in 7 scient ific papers.

Area of research: construction on settlement sensit ive soil.

Aim of the research: development a new technical solution to eliminate settlement of soils during construction in Moldova.

Objectives: to analyze the engineering-geological study degree of properties of settlement sensitive soils of Moldova; to study the main methods of settlement elimination; to generalize the experience of construction on settlement sensitive soils in Moldova; to obtain new data of physicomechanical, settlement and rheological characteristics of loess soils; to evaluate the effect of compaction on the soils characteristics, carried out with vibratory loader RG-installation; to study the microstructure of settlement sensitive soils and its change after the construction of soil piles; to investigate the stress-strain behavior of foundations; to substantiate the possibility of eliminating the settlement of foundation by execut ion the soil piles made with vibratory loader.

Scientific novelty and originality: are determined by development of an effective solution to compact settlement sensitive soils with vibrator. New data of settlement sensitive soils properties of Moldova was obtained; the values of the creep threshold for settlement sensitive loams were first determined; the reasons of possible decrease in strength of soils was investigated; for elimination the settlement properties, was used and scientifically substantiated the method of constructing soil piles using a vibratory loader; the effect of deep seals on the microstructure of settlement sensitive soils was been estimated by the method of decoding SEM images; the regional tables of characteristics of settlement sensitive soils of Moldova have been developed.

The importance of the scientific problem, solved in the study, is to obtain new data characterizing the properties of settlement sensitive soils in conditions of natural occurrence and after compaction by construction of soil piles using a vibratory loader.

Theoretical significance and applicative value of the thesis consists the possibility of using the obtained results for development the territories composed by II-nd type settlement soils. The role of rigid, irreversible structural cohesion links and water-colloidal links on the processes of strength reduction was identified. The effect of compaction of settlement sensitive soils using vibratory loader on its microstructure was investigated.

Implementation of the scientific results. The proposed technical solut ion for eliminat ion of settlement properties of so ils by execution of soil piles with vibrat ing loader RG-installat io n was used in preparing the foundations of residential buildings in the municipality of Chisinau. The tables of physico-mechanical characteristics of settlement sensitive soils developed by the author were accepted for use by the designers of the Incercom Inst itute.