Doctor of Philosophy

dissertationQuestar Corporation commissioned and funded this research, in partnership with the University of Utah and Bechtel Corporation, to develop methods of protecting steel natural gas pipelines crossing zones of permanent ground deformation. The goal of this research was the development and testing of an Expanded Polystyrene (EPS) Geofoam cover system for such pipelines across active faults or areas of permanent ground deformation (e.g., landslides, permafrost thaw, liquefaction-induced lateral spread). The goal of an EPS Geofoam cover system atop a buried pipeline is to reduce the lateral, longitudinal and vertical forces induced on the pipe as the surrounding ground undergoes permanent deformation. The properties of EPS Geofoam have distinct advantages that lead to improved pipe performance during large ground deformation. The most important of these are its low unit weight and relatively high compressibility. These advantages are the primary focus of this research. Further, the interaction of a pipe and EPS Geofoam was explored and analyzed in a loading case where the pipe was pushed directly into the EPS. In addition to laboratory-scale tests, full-scale tests were conducted with vertical and horizontal plane strain movement of pipe interacting with EPS Geofoam cover systems. Subsequently, numerical modeling was done of the field tests to further evaluate the use of an EPS cover system for applications experiencing large, permanent deformation. The results of the research program have shown that EPS Geofoam can be used as a cover system for steel pipelines crossings at active normal faults, or for other types of permanent ground deformation where the expected offset is predominately vertical

Settlement of Large Embankment Construction Adjacent to a Buried Gas Pipeline — A Case History in Settlement Mitigation Using Lightweight Fill

As part of the $1.7 Billion I-15 CORE highway reconstruction project in Utah, several new or enlarged large embankments were constructed adjacent to existing buried utilities. Lightweight fill was selected as the technology to limit distress to the adjacent utilities. In order to estimate the impact from new construction to the utilities, settlement estimates for the lightweight embankment were performed using traditional settlement estimating techniques. Numerical models using FLAC3D were then performed to refined estimates. Estimates of lightweight embankment foundation settlements from this construction were obtained from the finite difference modeling. Three-dimensional numerical modeling was used in order to evaluate the foundation settlements since numerical modeling can better estimate the induced stresses and deformations of subsurface soils for complicated geometry, loading history, and for locations outside of the loaded area. During and after construction of the embankments, foundation soil settlement was measured for the lightweight embankments. Settlement estimates from traditional engineering methods and the FLAC3D analyses were compared to the observed settlement data. Sensitive buried utilities were successfully protected by use of lightweight fills, and engineering settlement estimates were shown to agree well with measured settlement data. This case history shows how urban highway re-construction on soft soils, which will likely become more common in the future, can be designed and constructed to reliably protect existing structures

Resilient and Dynamic Modulus Testing For M-E Pavement Design

311247This project was originally funded with Principle Investigator (PI) Dr. Soonkie Nam, with Dr. Bret Lingwall as co-PI serving in a support role. The project began in late 2015, and the project was turned over to Dr. Lingwall as PI when Dr. Nam left SDSMT in August of 2017. Due to insurmountable equipment malfunctions, none of the dynamic modulus or flow number tests performed by the research team are reliable for use by SDDOT. The results are skewed by large temperature swings in the equipment. Despite many attempts to repair, the device continuous to pump heat into test specimens. As a result, we have agreed that the project be terminated. This report serves, by the mutual agreement reached on December 20th, 2019 at our in-person meeting in the Geotechnical Engineering Laboratory at The South Dakota School of Mines and Technology (SDSMT) (and confirmed in our follow-up communications) to summarize the work performed and close-out the research project SDDOT 2014-21

Surface Faulting Caused by the 2016 Central Italy Seismic Sequence: Field Mapping and LiDAR/UAV Imaging

The three mainshock events (M6.1 24 August, M5.9 26 October, and M6.5 30 October 2016) in the Central Italy earthquake sequence produced surface ruptures on known segments of the Mt. Vettore-Mt. Bove normal fault system. As a result, teams from Italian national research institutions and universities, working collaboratively with the U.S. Geothechnical Extreme Events Reconnaissance Association (GEER), were mobilized to collect perishable data. Our reconnaissance approach included field mapping and advanced imaging technique, both directed towards documenting the location and extent of surface rupture on the main fault exposure and secondary features. Mapping activity occurred after each mainshock (with different levels of detail at different times), which provides data on the progression of locations and amounts of slip between events. Along the full length of the Mt. Vettore-Mt. Bove fault system, vertical offsets ranged from 0-35 cm and 70-200 cm for the 24 August and 30 October events, respectively. Comparisons between observed surface rupture displacements and available empirical models show that the three events fit within expected ranges.Published1585-16104T. Sismicità dell'ItaliaJCR Journa

Bio-inspired geotechnical engineering: Principles, current work, opportunities and challenges

publishedVersio

Bio-inspired geotechnical engineering: principles, current work, opportunities and challenges

A broad diversity of biological organisms and systems interact with soil in ways that facilitate their growth and survival. These interactions are made possible by strategies that enable organisms to accomplish functions that can be analogous to those required in geotechnical engineering systems. Examples include anchorage in soft and weak ground, penetration into hard and stiff subsurface materials and movement in loose sand. Since the biological strategies have been ‘vetted’ by the process of natural selection, and the functions they accomplish are governed by the same physical laws in both the natural and engineered environments, they represent a unique source of principles and design ideas for addressing geotechnical challenges. Prior to implementation as engineering solutions, however, the differences in spatial and temporal scales and material properties between the biological environment and engineered system must be addressed. Current bio-inspired geotechnics research is addressing topics such as soil excavation and penetration, soil–structure interface shearing, load transfer between foundation and anchorage elements and soils, and mass and thermal transport, having gained inspiration from organisms such as worms, clams, ants, termites, fish, snakes and plant roots. This work highlights the potential benefits to both geotechnical engineering through new or improved solutions and biology through understanding of mechanisms as a result of cross-disciplinary interactions and collaborations

Engineering Reconnaissance Following the October 2016 Central Italy Earthquakes - Version 2

Between August and November 2016, three major earthquake events occurred in Central Italy. The first event, with M6.1, took place on 24 August 2016, the second (M5.9) on 26 October, and the third (M6.5) on 30 October 2016. Each event was followed by numerous aftershocks. As shown in Figure 1.1, this earthquake sequence occurred in a gap between two earlier damaging events, the 1997 M6.1 Umbria-Marche earthquake to the north-west and the 2009 M6.1 L’Aquila earthquake to the south-east. This gap had been previously recognized as a zone of elevated risk (GdL INGV sul terremoto di Amatrice, 2016). These events occurred along the spine of the Apennine Mountain range on normal faults and had rake angles ranging from -80 to -100 deg, which corresponds to normal faulting. Each of these events produced substantial damage to local towns and villages. The 24 August event caused massive damages to the following villages: Arquata del Tronto, Accumoli, Amatrice, and Pescara del Tronto. In total, there were 299 fatalities (www.ilgiornale.it), generally from collapses of unreinforced masonry dwellings. The October events caused significant new damage in the villages of Visso, Ussita, and Norcia, although they did not produce fatalities, since the area had largely been evacuated. The NSF-funded Geotechnical Extreme Events Reconnaissance (GEER) association, with co-funding from the B. John Garrick Institute for the Risk Sciences at UCLA and the NSF I/UCRC Center for Unmanned Aircraft Systems (C-UAS) at BYU, mobilized a US-based team to the area in two main phases: (1) following the 24 August event, from early September to early October 2016, and (2) following the October events, between the end of November and the beginning of December 2016. The US team worked in close collaboration with Italian researchers organized under the auspices of the Italian Geotechnical Society, the Italian Center for Seismic Microzonation and its Applications, the Consortium ReLUIS, Centre of Competence of Department of Civil Protection and the DIsaster RECovery Team of Politecnico di Torino. The objective of the Italy-US GEER team was to collect and document perishable data that is essential to advance knowledge of earthquake effects, which ultimately leads to improved procedures for characterization and mitigation of seismic risk. The Italy-US GEER team was multi-disciplinary, with expertise in geology, seismology, geomatics, geotechnical engineering, and structural engineering. The composition of the team was largely the same for the two mobilizations, particularly on the Italian side. Our approach was to combine traditional reconnaissance activities of on-ground recording and mapping of field conditions, with advanced imaging and damage detection routines enabled by state-of-the-art geomatics technology. GEER coordinated its reconnaissance activities with those of the Earthquake Engineering Research Institute (EERI), although the EERI mobilization to the October events was delayed and remains pending as of this writing (April 2017). For the August event reconnaissance, EERI focused on emergency response and recovery, in combination with documenting the effectiveness of public policies related to seismic retrofit. As such, GEER had responsibility for documenting structural damage patterns in addition to geotechnical effects. This report is focused on the reconnaissance activities performed following the October 2016 events. More information about the GEER reconnaissance activities and main findings following the 24 August 2016 event, can be found in GEER (2016). The objective of this document is to provide a summary of our findings, with an emphasis of documentation of data. In general, we do not seek to interpret data, but rather to present it as thoroughly as practical. Moreover, we minimize the presentation of background information already given in GEER (2016), so that the focus is on the effects of the October events. As such, this report and GEER (2016) are inseparable companion documents. Similar to reconnaissance activities following the 24 August 2016 event, the GEER team investigated earthquake effects on slopes, villages, and major infrastructure. Figure 1.2 shows the most strongly affected region and locations described subsequently pertaining to: 1. Surface fault rupture; 2. Recorded ground motions; 3. Landslides and rockfalls; 4. Mud volcanoes; 5. Investigated bridge structures; 6. Villages and hamlets for which mapping of building performance was performed

Reconnaissance of 2016 Central Italy Earthquake Sequence

The Central Italy earthquake sequence nominally began on 24 August 2016 with a M6.1 event on a normal fault that produced devastating effects in the town of Amatrice and several nearby villages and hamlets. A major international response was undertaken to record the effects of this disaster, including surface faulting, ground motions, landslides, and damage patterns to structures. This work targeted the development of high-value case histories useful to future research. Subsequent events in October 2016 exacerbated the damage in previously affected areas and caused damage to new areas in the north, particularly the relatively large town of Norcia. Additional reconnaissance after a M6.5 event on 30 October 2016 documented and mapped several large landslide features and increased damage states for structures in villages and hamlets throughout the region. This paper provides an overview of the reconnaissance activities undertaken to document and map these and other effects, and highlights valuable lessons learned regarding faulting and ground motions, engineering effects, and emergency response to this disaster

Protection of Pipelines and Buried Structures Using EPS Geofoam

Expanded Polystyrene (EPS) geofoam is a lightweight, compressible material that can be used to protect buried infrastructure in areas with high to moderate seismicity. This paper summarizes recent research conducted at the University of Utah regarding the seismic design and construction of EPS geosystems to improve the seismic resiliency of pipelines and buried structures, particularly at normal fault crossings. It discusses the development and verification of an EPS cover/backfill system to protect buried pipelines and other structures from potential rupture caused by permanent ground deformation (e.g., tectonic faulting, subsidence, liquefaction, land sliding, etc. Full-scale experiments and numerical modeling show that a light-weight cover system constructed, in part, with EPS block offers significant benefits in protecting buried pipelines from the damaging effects of offset caused by permanent ground deformation. The prototype EPS cover system significantly reduced the vertical uplift force and stresses imposed on the buried pipe system as it was subjected to uplift through the EPS cover system

Review and Refinement of SDDOT\u2019s LRFD Shallow Foundation Design Method

311232The objective of this project was to conduct a comprehensive review of Load Resistance Factor Design (LRFD) for bridge and wall shallow foundations. LRFD is a limit state design methodology based on reliability and probability. Specifically, this study investigated the concept, application, and implementation status of LRFD in shallow foundation designs for the South Dakota Department of Transportation (SDDOT) based on a review of the published research papers, American Association of State Highway and Transportation Officials (AASHTO) LRFD Bridge Design Specifications, bridge design manuals and/or geotechnical manuals of instruction (MOI) from other states, research reports published by many US state and federal agencies including Federal Highway Administration (FHWA), National Cooperative Highway Research Program (NCHRP), and the National Highway Institute (NHI), in addition to specifications used internationally. The results of this study show that the LRFD approach has already been adopted by most US states due to mandatory use on federally funded projects. However, whereas deep foundation design parameters are relatively well established for LRFD methods, local calibration of shallow foundation design parameters has not yet been performed in most states. This report examines the current status of LRFD and discusses its limited level of implementation for shallow foundation design in South Dakota, provides a set of recommendations that SDDOT can consider as it pursues implementation of LRFD in its construction projects with the ultimate goal of economical designs incorporating quantitative estimations of failure