Lars O Ericsson | Chalmers University of Technology (original) (raw)

Papers by Lars O Ericsson

Dagens nyheter, 2019

Undermarksplanerin

IOP Conference Series: Earth and Environmental Science, 2021

The subsurface can be used for a variety of purposes in the urban environment and the subsurface ... more The subsurface can be used for a variety of purposes in the urban environment and the subsurface should ultimately be seen as a multifunctional resource, offering a multitude of benefits to humans and the society. Underground construction is commonly planned according to the first come, first served principle and later claims on other resources in the subsurface will have to adapt, often at high costs, or are made impossible. This pilot study is a first step in developing a method aiming to investigate a procedure for mapping an area’s subsurface resources, having the multifunctionality of the subsurface in mind, and integrating this information into urban planning processes. A mapping of the existing resources (supporting, provisioning, regulating, cultural) used at present and their future potential is presented, and an analysis, using an interaction matrix, of how the different subsurface resources can influence each other (conflicts and synergies) if the use(s) changes. Conclusi...

Det här verket har digitaliserats vid Göteborgs universitetsbibliotek och är fritt att använda. A... more Det här verket har digitaliserats vid Göteborgs universitetsbibliotek och är fritt att använda. Alla tryckta texter är OCR-tolkade till maskinläsbar text. Det betyder att du kan söka och kopiera texten från dokumentet. Vissa äldre dokument med dåligt tryck kan vara svåra att OCR-tolka korrekt vilket medför att den OCR-tolkade texten kan innehålla fel och därför bör man visuellt jämföra med verkets bilder för att avgöra vad som är riktigt. Th is work has been digitized at Gothenburg University Library and is free to use. All printed texts have been OCR-processed and converted to machine readable text. Th is means that you can search and copy text from the document. Some early printed books are hard to OCR-process correctly and the text may contain errors, so one should always visually compare it with the images to determine what is correct.

Over the years and within different R&D projects, SKB, the Swedish Nuclear Fuel and Waste Managem... more Over the years and within different R&D projects, SKB, the Swedish Nuclear Fuel and Waste Management Company (SKB), has studied various aspects of a possible generated disturbed or damaged zone around a deposition tunnel for spent nuclear fuel. According to international nomenclature EDZ, the Excavation Damaged Zone, is defined as the blast damaged zone around a tunnel where the damage is not reversible. Knowledge about the EDZ and its possible hydraulic connectivity is essential for underground construction design, underground facility layout, work environment issues and analysis of post-closure safety. This paper will focus on strategies and methodology for determine the hydraulic connectivity of the EDZ for a KBS-3 nuclear waste repository. The integrated use of geological and geophysical methods will also be presented. Due to the hard rock conditions SKB has chosen drill and blast method for excavation of the repository of high level nuclear waste at the suggested site, Forsmark...

The coupling between hydraulic conductivity and normal stress along a discrete fracture has been ... more The coupling between hydraulic conductivity and normal stress along a discrete fracture has been developed from laboratory tests on small-scale samples. Those results for crystalline rock show a strong coupling between flow and normal stress, particularly when the normal stress is less than approximately 10 MPa. The flow for 611 discrete fractures was determined at the Forsmark site over depths ranging from 100 to 800 m. The orientation of the these discrete fractures were determined using Bips images and the normal stress acting on the fracture calculated from the in-situ stress model for the site. The strong coupling between stress and flow observed in small-scale laboratory tests is not supported by the in situ results.

$Research paper thumbnail of Fracture mapping for geological prognoses. Comparison of fractures from boreholes, tunnel and 3-D blocks$

One of the reasons for uncertainty in geological prognoses is that geological investigations, suc... more One of the reasons for uncertainty in geological prognoses is that geological investigations, such as drillings, only represent a small part of the rock mass, and that they may be directionally biased. This study is based on a unique set of data consisting of geological mapping of a tunnel during construction, fracture mapping from three core-drilled boreholes along the tunnel, and fracture mapping of blocks sawed out from a section of the same tunnel. By comparison of the different data sets it is shown how input data to geological models vary depending on what type of fracture mapping it is based on. The study focusses on orientation analysis of fractures using stereographic projection. The results indicate that there are obvious differences in the models due to sampling scale and dimensionality. Yet, the fracture mapping of tunnel faces and boreholes respectively was found to give similar results even though the scanlines along the boreholes are perpendicular to the tunnel faces. The results also indicates that there is a need to improve the detailed conceptual understanding at the tunnel site of the generation and intensity of fracture sets in order to make a reliable interpretation of fracture intensities and orientations.

$Research paper thumbnail of A compilation of size-dependent fracture$

International Journal of Rock Mechanics and Mining Sciences, 2009

Characterisation of thermal conductivity of rock and its spatial variability by laboratory measur... more Characterisation of thermal conductivity of rock and its spatial variability by laboratory measurements is costly and time-consuming. There is an incentive to find more cost-effective and rapid methods. A new empirical relationship between density and thermal ...

BeFo - Rock engineering research foundation, 2020

The subsurface is a precious, multifunctional and finite resource that should be managed in accor... more The subsurface is a precious, multifunctional and finite resource that should be managed in accordance with its full potential and its value to society. It can be used for a wide variety of purposes, which are not always compatible, and short-term use can conflict with long-term use and future possibilities. In Sweden, as well as in many countries worldwide, the “first-come-first-served” principle applies to getting access to the resources in the subsurface, compromising fair inter- and intragenerational distributions of these resources, and sustainable development. This report summarises the outcomes of the research project Sustainable use of underground space (SUB), financed by the Swedish research Council Formas and BeFo Rock Engineering Research Foundation. The aim of the project has been to investigate how subsurface dimensions can be integrated in urban planning processes and legislation, as well as proposing a framework for sustainable planning and use of the subsurface. The report contains a list of words and terminology used in relation to subsurface planning. The term subsurface planning is here defined as both a) consideration of subsurface conditions in surface planning, as well as b) making strategic considerations regarding the use of the subsurface in terms of use for construction purposes, or other types of subsurface resources. Chapter 1 introduces the background to the project and describes the methods used in the studies within the project. The methods used are a systematic literature review; a document and interview study of Swedish practice on inclusion of subsurface aspects in planning of a number of underground projects; a review of legislation and policy relevant to subsurface planning; and a pilot study for method development and for an inventory of resources in the subsurface. Chapter 2 summarises the role of geoscience in society, and specifically in spatial planning. This includes uncertainties in the parameters that are used to describe geological, thermal, hydrogeological, mechanical, chemical and biological properties of soil and rock, as well as exemplifying databases and base line studies that can be used in comprehensive planning. Chapter 3 places the subsurface as a multifunctional resource in an international context. A literature review reveals a need to bridge communication and knowledge gaps by appropriate subsurface information, easily conveyable in the appropriate format and at the right time, in a balanced quantity and quality. Information on regulations and policies for subsurface use is limited and fragmented in literature, although the interest in, and use of, the subsurface, have significantly increased in the last two decades. Chapter 4 gives an overview of Swedish subsurface planning from the 1970s to 2020. As early as 1975, at the inaugural annual meeting of the International Tunneling Association (ITA), the term subsurface planning was introduced. A pioneering Swedish study that was already ongoing at that point, aimed at providing the basis for legal regulations on responsibility for planning of subsurface use in spatial planning processes. In the past 40 years, a number of studies have been carried out in Sweden to support the development of a strategic subsurface planning. The chapter also provides a short description of two contemporary national projects “HUMP” and “Eko-Geokalkyl” which have contributed to a better integration of subsurface aspects in planning processes.Chapter 5 provides an overview of the development of the planning legislation in Sweden and explains contemporary Swedish planning legislation and policy that have implications on the subsurface. The overview includes planning and other related laws from 1600s to 2000s. The chapter provides a detailed description of the role of the Planning and Building Act (2010:305), the Environmental Code (1998:808), the Road Act (1971:948), the Construction of Railways Act (1995:1649), the Expropriation Act (1972:719), the Historic Environment Act (1988:950), the Protection of Essential Facilities Act (2010:305), as well as environmental policies in planning processes.Chapter 6 discusses subsurface usage in Sweden, and how the legislation is applied in spatial planning. Focus is on the Planning and Building Act, and the interaction between planning levels for which the local councils are responsible. A description of national projects that aim for digitalisation of the planning process is included. Also, other legislation that impacts the subsurface is discussed, related to e.g. construction of roads and railways, cultural heritage, energy, water and sewage systems, waste management, subsurface structures that are classified. Chapter 7 presents a pilot study, Flat\ue5s, which is an area located in Gothenburg, South-West Sweden. The pilot study aimed at mapping subsurface resources, investigating potential opportunities and conflicts between uses of these resources, and developing a proposal for how…

Undermarken kan i den urbana miljon anvandas for en mangd olika andamal: grundlaggning, uttag av ... more Undermarken kan i den urbana miljon anvandas for en mangd olika andamal: grundlaggning, uttag av grundvatten for t.ex. dricksvatten, lagring av varme, kyla och koldioxid, anlaggningar under markytan t.ex. garage, tunnlar, offentliga utrymmen, sportanlaggningar. Dessutom kan undermarken innehalla arkeologiska lamningar. Vidare kan jord och grundvatten vara fororenade och behova saneras. I det hallbara samhallet maste alla resurser anvandas och skyddas pa ett optimalt satt. Idag sker undermarksbyggande mer eller mindre oplanerat sa att den som forst gor ansprak pa utrymme under markytan ofta far fortur. Senare ansprak far anpassa sig, och da ofta till hoga kostnader. Syftet med foreliggande pilotstudie har varit att kartlagga ett omrades undermarksresurser for att battre kunna forsta mojliga konflikter under mark samt att battre kunna kommunicera de resurser som finns under mark. Genom att gora den typen av kartlaggning ar sedan malet att kunna peka ut framtida potentiella mojligheter...

Bulletin of Engineering Geology and the Environment, 2016

This paper presents a study of the hydrochemical changes that took place during construction of a... more This paper presents a study of the hydrochemical changes that took place during construction of a section of the Hallandsås rail tunnel in southwest Sweden based on monitoring from spring 2011 to summer 2012. Leakage into the tunnel during construction caused lowering of the groundwater levels, which in turn resulted in a decrease in or absence of base flow in the streams. The water in the streams became dominated by meteoric water during the drawdown periods. Meanwhile, wetlands were aerated, and oxygen could penetrate to oxidise reduced S, releasing acids and SO 4. The results for the groundwater in the bedrock differed spatially depending on local geological conditions. In each of the three monitored boreholes, higher redox potentials, higher concentrations of organic matter and lower concentrations of dissolved Mn and Fe were observed. In two of the boreholes, oxidation of pyrite, FeS 2 , present as a fracture mineral, caused the formation of SO 4 and acids with subsequent falls in pH and alkalinity. Leakage into underground constructions generally shortens the residence time of the groundwater significantly. Silicate weathering would thus become less important for the hydrochemistry compared to processes that occur during shorter time frames. As regards the durability of the tunnel, the hydrochemical changes observed in two of the three boreholes indicate a more aggressive environment for several parameters known to increase corrosivity of steel. The recovery of the groundwater levels occurred rapidly following completion of the waterproofing systems in the Tunnel. However, hydrochemical recovery with regard to major ions and pH occurred gradually and with an expected duration of several years.

INGENJ5RSGEOLOGISKA F5RUTS~TTNINGAR 5. 1 SammansUillning av li tteratur och kartmaterial Som grun... more INGENJ5RSGEOLOGISKA F5RUTS~TTNINGAR 5. 1 SammansUillning av li tteratur och kartmaterial Som grund for infiltrationsmatningarna har en geologisk analys av omradet utforts. I denna analys ingar en oversiktlig geologisk beskrivning av omradet samt en sammanstallning av det kartmaterial som har statt till forfogande. En enkel form av ingenjorsgeologisk karta har darefter upprattats.