Introduction to Advanced Geotechnical Testing

Hsin-yu ShanDept. of Civil Eng., NCTU

Concept of Site InvestigationPurpose of site investigation

A/E projects InfrastructuresFeasibility FeasibilityDevelopment permit PlanningEarthwork permit (grading) Basic designBuilding permit (structures) Detailed design

Stages of Site InvestigationSpatial: 3D 2D 1DExtent: large middle smallTime: past presentDifficulty: simple complexDensity: low highAmount of data: small largeCost: little a lot

Spatial3D: satellite images, aerial photos, geological maps, remote sensing data2D: geophysical exploration1D: boreholes, in-situ tests

ExtentLarge: regional geology, hydrogeologyMiddle: around the siteSmall: within the site

TimeHistorical information: geological history, history of development (land use)Present: boreholes, sampling, in-situ testing

DifficultyAvailable information collectionSite reconnaissance Site investigation – geophysical surveBorehole drilling, sampling, in-situ testing

DensityLow: 1/5000 mapsMiddle: accuracy of geophysical surveyHigh: density of boreholes, 1 /600 m2

Amount of InformationLittle: reports, mapsLarge: test results

CostLow: information collection, geophysical surveyHigh: drilling and sampling, in-situ testing

Values of InformationWhat types of information do we really need?Can we get these information by the methodology we employ today?Is the resources appropriately allocated to the methods we use?

What Do We Get from a Test?Index properties of soil/rockInformation of how a soil/rock behaves under certain conditions

What Do We Really Want to Know?

How the soil/rock behave under the “REAL” conditions in the futureHow can we design certain structuresMethods to deal with difficult conditionsPotential risks

“Advanced” Testing Methods?Data acquisitionAutomated controlAutomated report/graph generation

Additional soil properties

Value of InformationReliability Risk analysisValue engineering

Lowered costHigher degree of safety

Management of InformationValue chain analysis of informationDecision support systemQA/QC of information collection processKnowledge-base system

What Does “Advanced” Testing Means?

Save timeReduce errorFlexible testing scheme

Different type of informationMore accurate

What we get from these test results is still “data”, not

“information”, nor “knowledge”

What These “Advanced”Methods Cannot Provide

Knowledge of whether the information is neededKnowledge of whether the information is correctKnowledge of the value of informationKnowledge of how to utilize the information

What an Engineer RequiresKnowledge and wisdomFormulate information from test dataGenerate knowledge from the informationObtain wisdom from the experience

Before We Want to Specify a Test to be Conducted

The relevance of the testThe accuracy of the testThe cost of the testHow can we utilize the test results

DiscussionGeotechnical investigation for 5 ha site to be used as:

Semiconductor manufacturing factorySenior high school