Mariusz Lech

The use of resistivity and seismic cone penetration tests for site characterization

The use of resistivity and seismic cone penetration tests for site characterization The use of resistivity and seismic cone penetration tests for site characterization. Recent application of cone penetration tests to geotechnical and environmental site characterization has generated a wide collection of new sensors. This paper presents methods of interpreting geotechnical in situ investigations carried out by electrical resistivity (RCPT) and seismic (SCPT) cones. It contains some fundamental equations and the description of in situ electrical resistivity and shear wave velocity measurements and presents the results of SCPT and RCPT investigations at the experimental Stegny site in Warsaw. The aim of the paper is to present the approach to determination of shear wave velocity and porosity of clayey soils. According to the test results obtained, it can be concluded that both applied techniques are very useful to estimate the distribution of clay deposits and some of their geotechnical parameters. Obecnie obserwuje się dynamiczny rozwój zastosowań badań geotechnicznych, w tym zwłaszcza sondowań, do oceny stanu środowiska. W związku z tym można zaobserwować zapotrzebowanie na specjalistyczne badania podłoża gruntowego, mogące pomóc w określeniu różnych parametrów stosowanych w geotechnice środowiskowej, takich jak np. temperatura gruntu, oporność elektryczna, odczyn pH gruntu, potencjał redoks i innych. W niniejszym artykule przestawione zostały wyniki sondowań geotechnicznych stożkiem wyposażonym w moduł do pomiaru oporności elektrycznej gruntu (RCPT) oraz stożkiem sejsmicznym (SCPT). W artykule przedstawiono podstawowe informacje na temat techniki badań, opis stosowanych urządzeń oraz wyniki badań na terenie poligonu badawczego na Stegnach w Warszawie. Celem pracy było określenie zależności empirycznych pomiędzy parametrami uzyskanymi z badań sondami RCPT oraz SCPT a porowatością i prędkością fali poprzecznej badanych gruntów spoistych. Na podstawie przeprowadzonych badań można wnioskować, że zastosowane urządzenia pozwalające na pomiar oporności elektrycznej i prędkości rozchodzenia się fali poprzecznej w gruncie mogą być z powodzeniem wykorzystane do rozpoznania budowy geologicznej podłoża i określania pewnych parametrów gruntu.

Application of column tests and electrical resistivity methods for leachate transport monitoring

Abstract Development of the human civilization leads to the pollution of environment. One of the contamination which are a real threat to soil and groundwater are leachates from landfills. In this paper the solute transport through soil was considered. For this purpose, the laboratory column tests of chlorides tracer and leachates transport on two soil samples have been carried out. Furthermore, the electrical resistivity method was applied as auxiliary tool to follow the movements of solute through the soil column what allowed to compare between the results obtained with column test method and electrical resistivity measurements. Breakthrough curves obtained by conductivity and resistivity methods represents similar trends which leads to the conclusion about the suitability of electrical resistivity methods for contamination transport monitoring in soil-water systems.

Small strain stiffness in overconsolidated Pliocene clays

Abstract Small strain stiffness in overconsolidated Pliocene clays. A huge development of technical infrastructure, including the construction of many high-rise buildings, roads, railroads and extension of subway lines, took place over the recent years in Poland. Therefore, numerous planned investment projects require geotechnical data documenting the variation of soil parameters found in the subsoil. The shear wave velocity is one of the most important input parameters to represent the stiffness of the soil deposits. This paper focuses on the methods and devices using measurements of the shear wave velocity to estimate the initial shear modulus in cohesive soil. It is preferable to measure VS by in situ wave propagation tests, however it is often economically not feasible in all regions of Poland. Hence, a reliable correlation between shear wave velocity and parameters measured in triaxial cell or static penetration parameters would be a considerable advantage. This study shows results obtained from the bender elements tests and field techniques - seismic cone penetration test and seismic flat dilatometer, performed on overconsolidated cohesive soils in Warsaw. On the basis of the test results possible correlations between shear wave velocity (initial shear modulus), mean effective stress and void ratio are considered and four original empirical relationships are proposed. Moreover, the proposed formulas by two different techniques using triaxial apparatus and also RCPT cone were examined. The proposed formulas show a reasonable agreement with direct shear wave velocity profiles for clays and might be incorporated into routine laboratory and field practice

Electrical resistivity methods for landfill monitoring

Abstract Every single investment affects the natural environment, and that is why it is so important to eliminate nuisance it could cause. Extremely harmful effect on environment or human health could be expected from waste treatment facilities. One of the kinds of contamination which is a real threat to soil and water environment are leachates from landfills. They contain random chemical composition and can migrate from landfill through soil water flux leading to environmental pollution and degradation of groundwater. This paper focuses on the use of geophysical methods to assess migration of pollutants from the landfill through the subsoil. The laboratory tests of solute transport have been conducted on three soil samples from Łubna site to simulate the contamination flow. Migration of leachates through soil samples was controlled using the column test and electrical resistivity measurements which allow to com pare the results obtained with the standard column test method and electrical resistivity measurements. It leads to the conclusion that electrical resistivity methods for contamination transport monitoring in soil–water systems are suitable. Furthermore, field electrical resistivity tomography have been used for monitoring of the vertical sealing system in Łubna landfill.