20082008

Subsurface 3D Modeling:An Application to Waterfront Project

Planning and Site Evaluation

Andrew S. ThomasMoffatt & Nichol

600 University St, Ste 610Seattle, WA 98101T (206) 622-0222F (206) 622-4764

athomas@moffattnichol.com

20082008

INTRODUCTIONINTRODUCTION•Background / Significance

•Site Definition

•Subsurface 3D Models– Data Input– Applications– Sample Simulation

•Conclusions

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Background / SignificanceBackground / Significance

• Why is it important to know what lies Why is it important to know what lies beneath a project site?beneath a project site?

• How do subsurface conditions relate How do subsurface conditions relate to the waterborne transportation to the waterborne transportation industry?industry?

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Background / SignificanceBackground / Significance

Bodies of water have always provided a means of life

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Background / SignificanceBackground / Significance• Archaeological discoveries are Archaeological discoveries are

common near the waterfrontcommon near the waterfront

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Background / SignificanceBackground / Significance

• Archaeological discoveries can be Archaeological discoveries can be exciting and devastating at the same exciting and devastating at the same timetime

• Unanticipated finds can be costly to a Unanticipated finds can be costly to a projectproject

Archaeological InvestigationArchaeological InvestigationConstruction on scheduleConstruction on schedule

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Background / SignificanceBackground / Significance

• The waterborne transportation The waterborne transportation industry is vital in maintaining and industry is vital in maintaining and improving the world’s economyimproving the world’s economy

• Industry’s need for waterfront access Industry’s need for waterfront access pointspoints

• Waterfront sites have limited Waterfront sites have limited availability:availability:

increasing development = decreasing increasing development = decreasing availabilityavailability

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Site DefinitionSite Definition• Decreasing availability along the Decreasing availability along the

waterfront leads to increased waterfront leads to increased consideration of a site’s characteristicsconsideration of a site’s characteristics

• Site history – early considerationsSite history – early considerations– How will the development affect the site?How will the development affect the site?– How will the site affect the development?How will the site affect the development?– What lies beneath the site, and how can What lies beneath the site, and how can

its arrangement be conveyed to those that its arrangement be conveyed to those that need to know?need to know?

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Site DefinitionSite Definition

• Important to define and evaluate a Important to define and evaluate a site’s Area of Potential Effects (APE)site’s Area of Potential Effects (APE)

36 CFR Part 800 – Protection of Historic Properties36 CFR Part 800 – Protection of Historic Properties

Section 800.16 (Definitions):Section 800.16 (Definitions):

Area of Potential Effects: The geographic area or areas within which an undertaking may directly or indirectly cause alterations in the character or use of historic properties, if any such properties exist. The area of potential effects is influenced by the scale and nature of the undertaking and may be different for different kinds of effects caused by the undertaking.

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Site DefinitionSite Definition

-EXPERT INPUT-EXPERT INPUT-Aerial Photography-Aerial Photography-Historic Design -Historic Design DrawingsDrawings-Geologic Profiles-Geologic Profiles-Site Photographs-Site Photographs-Predictive & GIS Maps-Predictive & GIS Maps

• Sources of data for physical representation of APE:Sources of data for physical representation of APE:

-Survey Data-Survey Data-Environmental -Environmental StudiesStudies-Concept Drawings -Concept Drawings -Project Reports-Project Reports

• Data is collectively reviewed by:Data is collectively reviewed by:

• Widespread data collection and review can be Widespread data collection and review can be expensive and time-consuming; overall, data expensive and time-consuming; overall, data should be used effectively to justify the effortshould be used effectively to justify the effort

-Owners-Owners-Engineers & Planners-Engineers & Planners-Environmental Scientists-Environmental Scientists-Archaeologists-Archaeologists-Geologists-Geologists

-Geomorphologists-Geomorphologists-Cultural Resources -Cultural Resources ExpertsExperts-Regulatory Agencies-Regulatory Agencies-Other Stakeholders-Other Stakeholders

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Site DefinitionSite Definition

Subsurface Layers - Fence DiagramSubsurface Layers - Fence Diagram

• Data Data display display examplesexamples

Project Design - Plan & Section DrawingsProject Design - Plan & Section Drawings

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SUBSURFACE 3D SUBSURFACE 3D MODELSMODELS• A subsurface 3D model provides a single display A subsurface 3D model provides a single display of:of:– An existing site and its subsurface layersAn existing site and its subsurface layers– Historic excavations / impactsHistoric excavations / impacts– Proposed construction impactsProposed construction impacts

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SUBSURFACE 3D MODELSSUBSURFACE 3D MODELS

• Key features:Key features:– A subsurface 3D model exhibits thousands of A subsurface 3D model exhibits thousands of

precise, physical survey pointsprecise, physical survey points– 3D models are interactive3D models are interactive

• Users have the ability to rapidly zoom into or out of Users have the ability to rapidly zoom into or out of any point in the displayany point in the display

• A user can navigate around a 3D model by orbiting A user can navigate around a 3D model by orbiting the viewpoint so anything in the model can be seen the viewpoint so anything in the model can be seen from anywherefrom anywhere

– Sections cuts and measurements can be taken Sections cuts and measurements can be taken during a viewing sessionduring a viewing session

– Uninhibited display allows interpolations Uninhibited display allows interpolations between data points to be seen clearly at all between data points to be seen clearly at all timestimes

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Data InputData Input• The accuracy of the model depends on The accuracy of the model depends on

the accuracy of the data collectedthe accuracy of the data collected– Historic ExcavationsHistoric Excavations

•As-built drawingsAs-built drawings– Proposed ExcavationsProposed Excavations

•Concept Drawings (Alternative Project Layouts)Concept Drawings (Alternative Project Layouts)•Plan & Section DrawingsPlan & Section Drawings

– Existing Subterranean ConditionsExisting Subterranean Conditions•Project Report Graphs & FiguresProject Report Graphs & Figures•Geotechnical Boring LogsGeotechnical Boring Logs•Stratigraphic SectionsStratigraphic Sections•Archaeological Trench ProfilesArchaeological Trench Profiles•Topography - Survey Data / Contour LinesTopography - Survey Data / Contour Lines

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Data Input – Terrain Data Input – Terrain DevelopmentDevelopment

SurveySurvey Contour Lines Contour Lines Surface Surface DisplayDisplay

3D Contour Lines3D Contour Lines Resultant SurfaceResultant Surface

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Data Input –ExcavationsData Input –Excavations• Available design drawings can be used to locate Available design drawings can be used to locate

proposed and/or historic excavations in plan viewproposed and/or historic excavations in plan view

• If section drawings and grading plans are not If section drawings and grading plans are not available, excavation depths can be estimatedavailable, excavation depths can be estimated

• Once defined, excavations are cut into the 3D terrainOnce defined, excavations are cut into the 3D terrain

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Data Input – Subsurface ConditionsData Input – Subsurface Conditions

• Borehole Data: basis for Borehole Data: basis for defining subsurface defining subsurface formationsformations– Soil sample locations Soil sample locations

should be chosen should be chosen appropriatelyappropriately

– Layers can be initially Layers can be initially identified by reviewing identified by reviewing borehole/well logsborehole/well logs

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Data Input – Subsurface Data Input – Subsurface ConditionsConditions• Archaeological Archaeological TrenchesTrenches– If archaeological If archaeological

remnants are remnants are suspected, a series of suspected, a series of archaeological archaeological trenches are trenches are excavated and excavated and exploredexplored

– Trench profiles can be Trench profiles can be reviewed to provide reviewed to provide further subsurface further subsurface definition (IE more definition (IE more points to combine with points to combine with borehole data)borehole data)

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Data Input – Subsurface Data Input – Subsurface ConditionsConditions

• With data points, a triangulated irregular network With data points, a triangulated irregular network (TIN) is formed for each layer(TIN) is formed for each layer

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Applications – Sample ViewsApplications – Sample Views

Plan ViewPlan ViewSubterranean ViewSubterranean View

Section CutSection Cut

Cross SectionCross Section

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Applications – Comparison of Project Applications – Comparison of Project AlternativesAlternatives• Excavations from multiple Excavations from multiple

alternatives can be compared in the alternatives can be compared in the same modelsame model

Subterranean View – comparison of alternative utility layoutsSubterranean View – comparison of alternative utility layouts

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Applications – Layer Definition ProcessApplications – Layer Definition Process

• Some subsurface layers are more Some subsurface layers are more significant than others and require significant than others and require special considerationspecial consideration

• Example:Example:

Borings and TIN lines for a subsurface layerBorings and TIN lines for a subsurface layer

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Applications – Layer Definition ProcessApplications – Layer Definition Process

• Example continuedExample continued

Borings and TIN lines for a subsurface layerBorings and TIN lines for a subsurface layer

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Applications – Layer Definition ProcessApplications – Layer Definition Process

• Example continuedExample continued

Borings and TIN lines for a subsurface layerBorings and TIN lines for a subsurface layer

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Applications – Layer Definition ProcessApplications – Layer Definition Process

• Example – Final Definition of LayerExample – Final Definition of Layer

Borings and TIN lines Borings and TIN lines

for a subsurface layerfor a subsurface layer

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Sample SimulationSample Simulation

~4 minutes, 30 seconds~4 minutes, 30 seconds

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Conclusions – Subsurface 3D Conclusions – Subsurface 3D ModelingModeling• The application is a benefit to the waterborne The application is a benefit to the waterborne

transportation industrytransportation industry

• Provides a focal point for all interested parties Provides a focal point for all interested parties to view a site’s physical arrangement – proves to view a site’s physical arrangement – proves a universal understanding among a groupa universal understanding among a group

• An interactive viewing section allows a user to An interactive viewing section allows a user to navigate through the modelnavigate through the model

• Maximizes effectiveness of data collectedMaximizes effectiveness of data collected

• The waterfront is an integral part of the world’s The waterfront is an integral part of the world’s economic infrustructure -its sites should be economic infrustructure -its sites should be evaluated before commencing any evaluated before commencing any undertakings that could alter its character or undertakings that could alter its character or useuse

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Questions?Questions?

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Subsurface 3D Modeling:Subsurface 3D Modeling:An Application to Waterfront Project An Application to Waterfront Project

Planning and Site EvaluationPlanning and Site Evaluation

Andrew S. Thomas, EITMoffatt & Nichol

600 University St, Ste 610Seattle, WA 98101T (206) 622-0222F (206) 622-4764

athomas@moffattnichol.com