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Risk Management in Tunneling Projects: Estimation and Planning
KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Byggvetenskap, Jord- och bergmekanik.ORCID-id: 0000-0003-4824-420x
2024 (Engelska)Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
Abstract [en]

Cost overruns and schedule delays are frequently observed occurrences in the construction of transport infrastructure projects. Such phenomena lead to the mismanagement of significant amounts of both public and private resources.An examination of the literature reveals that uncertainty stands out as one of the potential primary causes of cost overruns and schedule delays. To address the impact of uncertainty on time and cost estimations in transport infrastructure projects, probabilistic approaches can be employed. 

In this doctoral thesis, first a conceptual risk model has been formulated specifically for the purpose of enhancing time and cost estimations in tunneling projects. This risk model serves as a tool to scrutinize and contrast existing probabilistic time and cost estimation models for tunnel projects, aiming to identify potential areas for improvement. Furthermore, the conceptual model is utilized to delve into the factors influencing the accuracy of subjective assessments regarding the input parameters in time estimation models. It also explores methods for incorporating the role of tunneling phases into the subjective assessment of these input parameters.

Then, enhancements and updates are introduced to the existingKTH model for time and cost estimation in tunneling projects. This model primarily targets three main sources of uncertainty: variability in construction performance, geological uncertainties, and the potential incidence of disruptive events. The analysis and improvements related to modelling of construction performance involve three sequential steps. In the first step, the construction process is modeled using the work breakdown structure (WBS), enabling a more realistic assessment of tunneling time. Subsequently, in the second step, PERT distributions are employed to model the uncertainty in the duration of unit activities, compared to the commonly used triangular distributions. The third step involves a detailed examination of a real tunnelling project's data to identify components contributing to construction performance variability for unit activities. This analysis pinpoints three main components: typical performance variability, minor performance delays, and minor machinery delays. These components are integrated into the KTH model, resulting in its further update concerning construction performance variability. 

A novel approach is introduced into the KTH model by leveraging the Metropolis-Hastings (MH) algorithm within the framework of Markov Chain Monte Carlo (MCMC) simulation to address geological uncertainties along the tunnel route. This method facilitates round-by-round simulation of the tunneling process and allows the model to accommodate uncertainty in the critical path for tunneling projects involving multiple headings. These enhancements aim to improve decision-making processes and mitigate risks associated with schedule delays and cost overruns. Additionally, the magnitude of disruptive events are now modeled as stochastic variables, an improvement on the original version of the KTH model.

Abstract [sv]

Kostnadsöverskridanden och förseningar i tidplanen inträffar ofta vidbyggande av transportinfrastrukturprojekt. Detta leder till slöseri av betydande resurser, både offentliga och privata. En genomgångav litteraturen visar att osäkerhet framträder som en av de potentiella primära orsakerna. För att hantera påverkan av osäkerhet på tid- och kostnadsuppskattningar i transportinfrastrukturprojekt kan probabilistiska metoder användas. I denna doktorsavhandling utarbetades först en konceptuell riskmodell som kan förbättra tid- och kostnadsuppskattningar specifikt i tunnelprojekt. Riskmodellen användes som ett verktyg för att granska och jämföra olika befintliga probabilistiska modeller för sådana skattningar, i syfte att identifiera möjliga förbättringsområden. Riskmodellen användes också för att undersöka faktorer som påverkar noggrannheten i subjektiva bedömningar av indata i tidsuppskattningsmodeller. Även metoder för att inkludera olika tunnelbyggnadsfaser i den subjektiva bedömningen av dessa indata utforskades. Forskningen har resulterat i förbättringar och uppdateringar av den befintliga KTH modellen för tid- och kostnadsuppskattning i tunnelprojekt. Modellen inriktar sig mot tre huvudsakliga källor till osäkerhet i skattningen: variabilitet i arbetsprestation, geologisk osäkerhet och förekomstav försenande händelser. Analysen och förbättringarna av modelleringen av arbetsprestation utfördes i tre steg. I det första stegetmodellerades byggprocessen med hjälp av en så kallad Work Breakdown Structure (WBS), vilket möjliggör en mer realistisk bedömningav tunnelprojektets byggtid. I det andra steget användes PERTfördelningar för att modellera osäkerheten i tidsåtgång för de olika aktiviteterna i produktionscykeln, istället för den annars ofta använda triangelfördelningen. Det tredje steget utgjordes av en detaljerad undersökning av data från ett verkligt tunnelprojekt föratt identifiera vilka komponenter som bidrar till variabiliteten i arbetsprestation i produktionscykelns olika aktiviteter. Denna analyspekar ut tre huvudkomponenter: typisk variabilitet i arbetsprestation, mindre prestationsförseningar och mindre maskinförseningar. Dessa komponenter integrerades i KTH-modellen, vilket resulteradei ytterligare uppdateringar avseende variabiliteten i arbetsprestation. En ny metod infördes i KTH-modellen genom att använda Metropolis-Hastings-algoritmen inom ramen för Monte Carlo-simuleringmed Markovkedjor, för att hantera geologiska osäkerheter längstunnelsträckningen. Denna metod möjliggör stegvis simulering av tunnelbyggnadsprocessen så att KTH-modellen nu kan beakta osäkerhet i kritiska linjen i tunnelprojekt med flera fronter. Dessa förbättringar syftar till att underlätta beslutsfattandet och minska riskerna för förseningar och kostnadsöverskridanden. Dessutom är det nu möjligt att modellera storleken på försenande händelser som stokastiska variabler, vilket är en annan förbättring jämfört med den ursprungliga versionen av KTH-modellen. 

Ort, förlag, år, upplaga, sidor
Stockholm: KTH Royal Institute of Technology, 2024.
Serie
TRITA-ABE-DLT ; 248
Nyckelord [en]
Cost overrun, Transport infrastructure projects, Time and cost estimation, Probabilistic approaches, Tunneling
Nationell ämneskategori
Teknik och teknologier
Forskningsämne
Byggvetenskap, Jord- och bergmekanik
Identifikatorer
URN: urn:nbn:se:kth:diva-345073ISBN: 978-91-8040-886-8 (tryckt)OAI: oai:DiVA.org:kth-345073DiVA, id: diva2:1849278
Disputation
2024-05-03, Kollegiesalen, Brinellvägen 8, https://kth-se.zoom.us/j/66341214998, Stockholm, 10:00 (Engelska)
Opponent
Handledare
Anmärkning

QC240410

Tillgänglig från: 2024-04-10 Skapad: 2024-04-05 Senast uppdaterad: 2024-04-10Bibliografiskt granskad
Delarbeten
1. Models to Analyze Risk in Time and Cost Estimation of Tunneling Projects
Öppna denna publikation i ny flik eller fönster >>Models to Analyze Risk in Time and Cost Estimation of Tunneling Projects
2024 (Engelska)Ingår i: Geotechnical and Geological Engineering, ISSN 0960-3182, E-ISSN 1573-1529, Vol. 42, nr 2, s. 1445-1457Artikel i tidskrift (Refereegranskat) Published
Abstract [en]

Time and cost estimation of tunnelingprojects is usually performed in a deterministic manner.However, because the deterministic approach isnot capable of dealing with uncertainty, probabilisticmethods have been developed over the years to betteraccount for this problem. Three models of this typeare the Decision Aids for Tunneling (DAT) and twomodels developed at KTH Royal Institute of Technologyand the Czech Technical University in Prague.To conduct a probabilistic time and cost estimation,it is important to understand and account for not onlythe uncertain factors that affect the project time andcost but also the involved parties’ different interestsand contractual responsibilities. This paper developsa risk model for the specific purpose of time andcost estimation of tunneling projects. In light of thismodel, the practical application of the three probabilisticmodels is discussed from a risk-aware decisionmaker’sperspective. The acquired insights can behelpful in increasing the experts’ risk-awareness inmodeling time and cost of tunneling projects.

Ort, förlag, år, upplaga, sidor
Springer Nature, 2024
Nyckelord
Time and cost estimation · Tunneling projects · Probabilistic approaches · Risk model · Uncertainty
Nationell ämneskategori
Samhällsbyggnadsteknik
Forskningsämne
Byggvetenskap, Jord- och bergmekanik
Identifikatorer
urn:nbn:se:kth:diva-344904 (URN)10.1007/s10706-023-02627-x (DOI)001062070900001 ()2-s2.0-85169165496 (Scopus ID)
Forskningsfinansiär
Forskningsrådet Formas, 2017-01218Stiftelsen Bergteknisk Forskning (BeFo), 400KTH
Anmärkning

QC 20240403

Tillgänglig från: 2024-04-02 Skapad: 2024-04-02 Senast uppdaterad: 2024-04-05Bibliografiskt granskad
2. Probabilistic Time Estimation of Tunneling Projects: The Uri Headrace Tunnel
Öppna denna publikation i ny flik eller fönster >>Probabilistic Time Estimation of Tunneling Projects: The Uri Headrace Tunnel
2023 (Engelska)Ingår i: Rock Mechanics and Rock Engineering, ISSN 0723-2632, E-ISSN 1434-453X, Vol. 56, nr 1, s. 703-717Artikel i tidskrift (Refereegranskat) Published
Abstract [en]

Probabilistic time estimation is an essential part of proper risk management in tunneling projects. In recent decades, several models have been developed for this purpose, one of which was developed by Isaksson and Stille (Rock Mech Rock Eng 38:373–398, 2005). In this paper, Isaksson and Stille’s probabilistic time and cost estimation model was improved and then applied to estimate the total tunneling time of the headrace tunnel in the Uri hydropower project in India. The improvements allow the user to more accurately account for different types of geological features and disruptive events. The result of the estimation is a distribution of tunneling time. The outcome illustrates how a proper understanding of the geological setting of the project and its effect on construction performance can contribute to effective risk management. 

Ort, förlag, år, upplaga, sidor
Springer Nature, 2023
Nyckelord
Overrun, Probabilistic approaches, Risk management, Time and cost estimation, Tunneling, Cost benefit analysis, Cost estimating, Geology, Project management, Risk perception, Uncertainty analysis, Cost estimations, Headrace tunnel, Probabilistics, Probabilistics approach, Risks management, Time estimation, Tunneling project, Tunneling time, hydroelectric power plant, numerical model, parameter estimation, probability, risk assessment, India
Nationell ämneskategori
Geoteknik
Identifikatorer
urn:nbn:se:kth:diva-326790 (URN)10.1007/s00603-022-03022-3 (DOI)000839440300001 ()2-s2.0-85135806373 (Scopus ID)
Anmärkning

QC 20230515

Tillgänglig från: 2023-05-15 Skapad: 2023-05-15 Senast uppdaterad: 2024-04-05Bibliografiskt granskad
3. Modeling uncertainty of activity duration in probabilistic time estimation of tunneling projects
Öppna denna publikation i ny flik eller fönster >>Modeling uncertainty of activity duration in probabilistic time estimation of tunneling projects
2023 (Engelska)Ingår i: Proceedings 15th ISRM Congress 2023 & 72nd Geomechanics Colloquium, Salzburg: Austrian Society for Geomechanics , 2023, s. 403-408Konferensbidrag, Poster (med eller utan abstract) (Refereegranskat)
Abstract [en]

The PERT distribution may be a suitable distribution for modeling activities’ duration in probabilistic time estimation of tunnel projects as it puts more emphasis on the mean value of the distribution. In this paper, we compared the outcome of time estimations for a tunnel, using the triangular and PERT distributions for modeling the uncertainty of activities’ duration. The results indicate that the choice of the distribution affects the total estimated time considerably. In addition, the skewness of the distribution also affects the results of estimation meaning that realistic assessment of the parameters of the distributions is important.

Ort, förlag, år, upplaga, sidor
Salzburg: Austrian Society for Geomechanics, 2023
Nyckelord
Time estimation, Probabilistic approaches, Tunneling, Activity duration, Production effort
Nationell ämneskategori
Samhällsbyggnadsteknik
Forskningsämne
Byggvetenskap, Jord- och bergmekanik
Identifikatorer
urn:nbn:se:kth:diva-344905 (URN)
Konferens
15th ISRM Congress 2023 & 72nd Geomechanics Colloquium, Salzburg, Austria, October 09th - 14th, 2023
Forskningsfinansiär
Forskningsrådet FormasStiftelsen Bergteknisk Forskning (BeFo), 400
Anmärkning

QC 20240403

Tillgänglig från: 2024-04-02 Skapad: 2024-04-02 Senast uppdaterad: 2024-04-05Bibliografiskt granskad
4. Modelling construction performance variability for probabilistic time estimation of tunneling projects
Öppna denna publikation i ny flik eller fönster >>Modelling construction performance variability for probabilistic time estimation of tunneling projects
2024 (Engelska)Manuskript (preprint) (Övrigt vetenskapligt)
Abstract [en]

Budget overrun and schedule delay of infrastructure projects result in mismanagement of huge amounts of resources. Studies show that accounting for uncertainties in time and cost estimation of such projects can help the decision-makers in better understanding the involved risks. Several probabilistic models have been developed during the last two decades to facilitate such estimations. A common aspect of all these models is the subjective assessment of unit activities’ duration, which affects the accuracy of the estimated time and cost significantly. Despite this, the mechanism governing the variability of unit activities’ duration has seldom been studied. Thus, this paper focuses on addressing this gap by using a unique set of data from a tunnel project. The variability in unit activities’ duration (construction performance variability) is governed by three main components: typical performance variability, minor machinery delays, and minor performance delays. Using these components, a novel method for modeling construction performance variability in probabilistic time estimation of tunneling projects is proposed. The application of the proposed method is demonstrated through a case example with a discussion on its important aspects, advantages, and limitations. The findings of this paper offer a resource to improve the accuracy of time estimation for tunneling projects.

Nyckelord
Probabilistic approaches; Time estimation; Construction variability; Activity duration; Production effort
Nationell ämneskategori
Samhällsbyggnadsteknik
Forskningsämne
Byggvetenskap, Jord- och bergmekanik
Identifikatorer
urn:nbn:se:kth:diva-344906 (URN)
Anmärkning

QC 20240403

Tillgänglig från: 2024-04-02 Skapad: 2024-04-02 Senast uppdaterad: 2024-04-05Bibliografiskt granskad
5. Probabilistic time estimation of underground structures constructed with multiple headings
Öppna denna publikation i ny flik eller fönster >>Probabilistic time estimation of underground structures constructed with multiple headings
(Engelska)Manuskript (preprint) (Övrigt vetenskapligt)
Abstract [en]

Transport infrastructure projects frequently encounter challenges such as schedule delays and cost overruns, leading to substantial misallocation of public or private resources. These issues are often exacerbated by uncertainties in time and cost estimation outcomes. To address this, various models have been developed in recent years to enable probabilistic estimation for tunneling projects, considering uncertainties. However, the impact of uncertainties on the critical path and its implications on time and cost estimations have not been explored for network underground structures encompassing multiple construction paths. In this study, we update the KTH time and cost estimation model using the Markov Chain Monte Carlo (MCMC) method. This updated model enables simultaneous round-by-round construction simulation across all paths in network underground structures. Consequently, it accommodates uncertainty in the critical path and its influence on time estimation outcomes. Additionally, the updated model introduces an innovative technique to model geological uncertainties along tunnel routes, thereby contributing to the field's diversity. Practical application of the updated model is showcased using the Uri Hearace tunnel as an illustrative example. The paper also delves into the practical implications of the findings from a decision-maker's standpoint, as well as discussing the model's limitations.

Nyckelord
Construction time, Construction path, Underground structure, Markov Chain Monte Carlo, Production effort
Nationell ämneskategori
Teknik och teknologier
Forskningsämne
Byggvetenskap, Jord- och bergmekanik
Identifikatorer
urn:nbn:se:kth:diva-345071 (URN)
Anmärkning

QC 20240411

Tillgänglig från: 2024-04-05 Skapad: 2024-04-05 Senast uppdaterad: 2024-04-11Bibliografiskt granskad
6. RISK MODEL FOR UNDERSTANDING UNCERTAINTY IN TIME AND COST ESTIMATION IN TUNNELING PHASES
Öppna denna publikation i ny flik eller fönster >>RISK MODEL FOR UNDERSTANDING UNCERTAINTY IN TIME AND COST ESTIMATION IN TUNNELING PHASES
2023 (Engelska)Konferensbidrag, Poster (med eller utan abstract) (Refereegranskat)
Abstract [en]

Probabilistic time and cost estimation is a useful approach to assist decision-making under uncertainty concerning budget and duration of tunneling projects. In recent years, several models have been developed that can be used for this purpose, where the subjective assessments of the values of input parameters conducted by estimators are of crucial importance for the accuracy of the estimated time and cost. However, the factors that can affect the accuracy of the subjective assessments are not studied thoroughly in the literature. Thus, we discuss these affecting factors from the perspective of a conceptual risk model that can be used for the specific purpose of time and cost estimation of tunneling projects. In addition, by defining three pre-operational phases in the lifetime of tunneling projects (initiation, planning, and construction), we explain how these phases come into play when assessing the input parameters of the models. 

Nationell ämneskategori
Reglerteknik
Forskningsämne
Byggvetenskap, Jord- och bergmekanik
Identifikatorer
urn:nbn:se:kth:diva-345072 (URN)
Konferens
Underground construction Prague 2023, 29-05-2023 - 31-05-2023
Anmärkning

QC 20240409

Tillgänglig från: 2024-04-05 Skapad: 2024-04-05 Senast uppdaterad: 2024-04-10Bibliografiskt granskad

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