Shannon and Wilson Inc.
Shannon and Wilson Inc.
Anderson S.A.,BGC Engineering Inc. |
Vessely M.J.,Shannon and Wilson Inc. |
Ortiz T.,Geohazards Program Manager
Geotechnical Special Publication | Year: 2017
The Colorado Department of Transportation (CDOT) has recently implemented a risk-based transportation asset management plan (RB TAMP) that incorporates geotechnical assets and hazards. CDOT's RB TAMP includes an ancillary wall structures program that includes all earth retaining structures, and a geohazards management program which is used to manage multiple hazards related to slopes, embankments, and roadway subgrade. The RB TAMP states multiple performance goals to be achieved, including safety, infrastructure condition, reliability, congestion, and maintenance, and the state will measure and report progress in these areas. Natural hazards, physical failures, external agency impacts and operational risks are risk types that present threats to CDOT's achievement of their goals. The way these risks act on assets to impact performance goals can be visualized in a cubic form, and this allows for recognition of how many elements of risk there are, for making explicit decisions on which risks to address and how, and for communicating these decisions to others. Risk analysis at CDOT includes both qualitative and quantitative approaches in accordance with data availability. The quantitative estimate of risk is expressed in terms of exposure cost for all assets, risk types and performance goals and then used by CDOT subject matter experts for project selection and planning. © 2017 ASCE.
Mesri G.,University of Illinois at Urbana - Champaign |
Funk J.R.,Shannon and Wilson Inc.
Journal of Geotechnical and Geoenvironmental Engineering | Year: 2015
The Kansai International Airport was constructed in Osaka Bay in 18- to 20-m-deep seawater to avoid noise pollution and land acquisition disputes. Construction of the 511-ha Island I began in 1987 and Runway I began operation in 1994. Construction of the 545-ha Island II began in 1999, and Runway II began operation in 2007. Using more than 2.2 million vertical sand drains fully penetrating into the 17.3- to 24.1-m-thick Holocene clay layer and 430 million cubic meters of fill material, the project is viewed as an engineering marvel. On the basis of a detailed review of the geology of Osaka Bay, construction of the Airport Islands, and the permeability and compressibility of the Holocene and Pleistocene subseabed deposits that reached a depth of 400 m below the seafloor at the Kansai Airport site, settlement analyses were conducted assuming the uniqueness of end-of-primary void ratio-effective vertical stress relationship and the Cα/Cc law of compressibility. Airport Island I has already settled below the 4-m above sea level surface elevation required by the design specification, and the surface elevation of Island II is predicted to be 4 m above sea level by 2023-2036. Airport Islands I and II will be at sea level, respectively, by 2067 or sooner and by 2058-2100. By the end of the 21st century, Island I and Island II are predicted to settle, respectively, 17.6 and 24.4 m. © 2014 American Society of Civil Engineers.
Peterson C.D.,Portland State University |
Minor R.,Heritage Research Associates Inc. |
Peterson G.L.,Shannon and Wilson Inc. |
Gates E.B.,128 NW Harriman St.
Geomorphology | Year: 2011
Geomorphic landscape development in the pre-Holocene ancestral Columbia River Valley (1-5km width) in the Portland forearc basin (~50km length) is established from depositional sequences, which pre-date and post-date the glacial Lake Missoula floods. The sequences are observed from selected borehole logs (150 in number) and intact terrace soil profiles (56 in number) in backhoe trenches. Four sequences are widespread, including (1) a vertically aggraded Pleistocene alluvial plain, (2) a steep sided valley that is incised (125-150m) into the Pleistocene gravel plain, (3) Missoula flood terraces (19-13ka) abandoned on the sides of the ancestral valley, and (4) Holocene flooding surfaces (11-8ka) buried at 70-30m depth in the axial Columbia River Valley. Weathering rims and cementation are used for relative dating of incised Pleistocene gravel units. Soil development on the abandoned Missoula flood terraces is directly related to terrace deposit lithology, including thin Bw horizons in gravel, irregular podzols in sand, and multiple Bw horizons in thicker loess-capping layers. Radiocarbon dating of sand and mud alluvium in the submerged axial valley ties Holocene flooding surfaces to a local sea level curve and establishes Holocene sedimentation rates of 1.5cmyear-1 during 11-9ka and 0.3cmyear-1 during 9-0ka. The sequences of Pleistocene gravel aggradation, river valley incision, cataclysmic Missoula flooding, and Holocene submergence yield complex geomorphic landscapes in the ancestral lower Columbia River Valley. © 2011 Elsevier B.V.
Wang Y.,Shannon and Wilson Inc. |
Wang Y.,University of Texas at Austin |
Tonon F.,University of Texas at Austin
International Journal of Rock Mechanics and Mining Sciences | Year: 2011
A discrete element code has been developed to simulate dynamic behavior of rock materials, particularly rock fragmentation upon impact in rock-fall analysis. Dynamic compression tests at a lower strain rate regime (ε<0.2s-1) and Split Hopkinson Pressure Bar tests at a higher strain rate regime (ε>10.0s-1) have been performed to validate the discrete element code. The dynamic strength and fragment size distribution of the tested granite showed clear strain rate dependence; the dynamic strength of granite increases with strain rate and a higher strain rate loading tends to produce more fragments. It has been found that the developed discrete element code can reasonably simulate the dynamic behavior in terms of strain rate dependent dynamic strength but not fragment size distribution. The strain rate dependent dynamic strength of granite can be explained as an inertial effect, in which material inertia inhibits crack propagations. The experimental fragment size distribution can be well represented by a two-parameter Weibull distribution. © 2011 Elsevier Ltd.
Wang Y.,Shannon and Wilson Inc. |
Wang Y.,University of Texas at Austin |
Tonon F.,University of Texas at Austin
Rock Mechanics and Rock Engineering | Year: 2011
A discrete element code has been used to simulate impact-induced rock fragmentation in rock fall analysis using a simplified impact model inspired by the theory of vibrations for foundations on elastic media. The impact velocity, the angle of incidence, pre-existing fractures, and the ground stiffness all play important roles in impact fragmentation. Based on the simulation results, impact fragmentation occurs locally at the impact zone without generating large fragments for a homogeneous rock block. Large fragments are generated only when there are open pre-existing fractures in the rock block or when there are fully persistent closed fractures. Softer ground tends to reduce the potential for impact fragmentation. Energy transformation and failure occur only during impact including approach and restitution stages. Friction energy loss accounts for most of the energy loss during the fragmentation process, while tensile cracking energy loss is not significant. © 2010 Springer-Verlag.
Nitschke A.G.,Shannon and Wilson Inc. |
Winterberg R.,EPC Elasto Plastic Concrete
ITA-AITES World Tunnel Congress 2016, WTC 2016 | Year: 2016
Macro synthetic fiber reinforced concrete or shotcrete is seen by many design engineers as offering a viable alternative to steel reinforcement in tunnel linings. The technology is now commonplace for primary and permanent ground support in both mining and civil tunnel applications. It has for instance become the standard form of reinforcement in the Australian mining industry, and has been used for a majority of permanent tunnel linings in recent tunnel construction in Norway. Similarly, macro synthetic fibers are becoming a standard solution for the initial lining in the USA. The use of macro synthetic fiber offers innovative solutions, yielding robust and sustainable tunnel lining designs. Citing recent research and actual projects, this paper presents state-of-the-art design considerations for fiber reinforced tunnel linings relating to structural and long-term performance. Topics include seismic resistance, crack width control, corrosion and durability, as well as sustainment of performance with age. Copyright © (2016) by the Society for Mining, Metallurgy and Exploration. All rights reserved.
Stuedlein A.W.,Oregon State University |
Neely W.J.,Flatiron West Inc. |
Gurtowski T.M.,Shannon and Wilson Inc.
Journal of Geotechnical and Geoenvironmental Engineering | Year: 2012
Although a variety of methods exist to estimate axial capacity for augered cast-in-place piles, they are generally limited to allowable stress design (ASD) procedures, with little consideration of design reliability. This paper describes the addition of static loading test results to a global augered cast-in-place pile data set to assess the accuracy of new and existing design methods and to address the current lack of reliability-based design methods for augered cast-in-place piles. The new static loading tests in western Washington were carried out on piles installed in granular materials, with pile diameters and lengths ranging from 0.41 to 0.51 m and 9.5 to 29 m, respectively. The preparation of beta coefficients and unit toe bearing resistance values is discussed within the framework of strain-dependent composite tangent moduli and observed residual loads. New relationships for the beta coefficient and toe bearing resistance values are proposed, and the accuracy of new and existing design procedures is statistically characterized using the updated global data set. Resistance factors for axial compression and uplift are calibrated at the strength limit for use in load and resistance factor design (LRFD). © 2012 American Society of Civil Engineers.
Robinson R.A.,Shannon and Wilson Inc.
Proceedings - Rapid Excavation and Tunneling Conference | Year: 2013
Seattle has experienced 130 years of increasingly challenging tunneling with more than 150 tunnels totaling over 120 km beneath hilly topography and through complexly interbedded glacial and inter-glacial soils. Local geotechnical challenges include: multiple perched groundwater levels, abrasive granular soils, sticky clogging clays, high strength boulders, "mixed-face" conditions, isolated methane inflows, and man-made obstructions and various contaminants. To handle these conditions local tunneling has evolved through at least four phases defined by: (1) hand-mining and timber support augmented with compressed air ground stabilization; (2) excavation with pneumatic spaders, electric and diesel powered equipment, chemical grouting, and mechanized concrete shuttle forms; (3) digger shields with steel and concrete segment support, deep well and eductor/ejector dewatering, waterpro of membranes, jet and compaction grouting, and risk sharing with baseline reports and dispute review boards; and (4) today's closed-face tunnel boring machines (TBMs) with on-line monitoring and single pass gasketed pre-cast segments, all capable of handling over 60 m of groundwater head. Current and recent projects include TBMs with excavation diameters of 1.5 m to 17.5 m and capable of working at groundwater pressure of over 6 bars.
Hoopes O.,Shannon and Wilson Inc. |
Hughes J.,Hughes Insitu Engineering Ltd.
Journal of Geotechnical and Geoenvironmental Engineering | Year: 2014
Pressuremeter testing was conducted for the State Route (SR) 99 Bored Tunnel project in Seattle, Washington, to estimate in situ soil stress-deformation parameters along the tunnel alignment. Many of the tests were conducted in a very stiff to hard glaciolacustrine clay known as Seattle clay. This unit is historically known for deep-seated slope failures and many of these failures have been attributed to the release of high, locked-in lateral stresses. Estimation in situ lateral stresses along the tunnel alignment was a primary focus of the exploration program. Due to the hard consistency of this unit and the potential for cobbles, neither self-boring pressuremeter nor dilatometer testing was feasible; therefore, pre-bored pressuremeter testing was used. Using several lateral stress estimation techniques, including a novel in situ creep testing approach, the in situ lateral stresses in the Seattle clay were estimated to be significantly higher than what would be expected by assuming a simple, laterally constrained, vertical loading and unloading stress path due to glaciation. Deformational features commonly encountered in Seattle clay indicate its stress history also has included significant lateral shearing. The memory of this shearing within the fabric of the clay may influence the in situ stress state and response to lateral unloading. © 2013 American Society of Civil Engineers.
Brennan K.,Shannon and Wilson Inc.
Proceedings of the International Conference on Cold Regions Engineering | Year: 2015
The Port MacKenzie Rail Extension project is an approximately 51.5-km-long rail spur extending south from the existing Alaska Railroad mainline in Houston, Alaska, to Port MacKenzie on the north end of the Cook Inlet. The rail spur alignment crosses largely undeveloped land and approximately 8 km of poorly drained, boggy wetland areas. Many of the wetland areas are incapable of supporting construction vehicle traffic during the summer season. To facilitate embankment construction in these wetlands during the summer, an approach to constructing the base of embankments over firm, frozen ground during the winter (winter embankment base stabilization (WEBS)) was developed. Several configurations to the WEBS construction were considered using soil fill and geosynthetics. A test section was constructed and instrumented using horizontal slope indicators and vertical thermistor strings during the first winter season of construction for four variations of fill thickness and reinforcement. The results of the test section and observations during construction of the WEBS during the first summer construction season were used to refine the approach for subsequent construction seasons. After three construction seasons, a significant amount of real-world performance and construction observations were available to evaluate the effectiveness of the WEBS over seasonally frozen ground. Additional comparisons of the WEBS construction approach to several embankments constructed in wetlands under summer conditions were also available. This paper provides settlement and ground temperature data collected at the WEBS test sections, observations of WEBS performance, recommended construction approaches over seasonally frozen ground, and a review of the efficacy of the recommended approaches. Conditions where WEBS should be utilized and lessons learned are discussed. © ASCE.