Flashcards
Geo M3
Cards in this deck (83)
- 1“The theoretical and applied science of the mechanical behaviour of rock and rock masses in response to force fields of their physical environment.” ✓ Engineering Rock Mechanics ✓ Geological Rock MechanicsRock Mechanics
- 2➢ Strength of the rock is dependent on its physico-chemical composition. ➢ Physico-mechanical characteristics of same rock type may varyRock Features
- 3➢ Rocks are strong in taking compressive load but relatively weak in taking tensile load ➢ Rocks behave mostly as brittle material but may behave as ductile/plasticRock Features
- 4➢ intrinsic property ➢ the storage capacity of the geologic materialPorosity
- 5➢ ranges from < 1% in crystalline rocks like granite to over 55% in some soils.Primary Porosity
- 6➢ - porosity of some rock is increased through fractures or solution of the material itselfSecondary Porosity
- 7➢ igneous or metamorphic rocks (0-2%) ➢ sedimentary rocks (up to 40%)Porosity
- 8➢mass of water contained in a rock sample after one hour period of immersion ➢ ratio of difference between the saturated and dry weight of rock to dry weight of rockPorosity
➢ Void Index - 9➢ relative interconnection of pores ➢“If the material has high permeability than pore spaces are connected to one another allowing water to flow from one to another, however, if there is low permeability then the pore spaces are isolated and water is trapped within them.”Permeability
- 10➢ evaluates the degree of fissuring ➢ Uniaxial Compressive Strength (UCS) testing ▪ estimating in situ rock strength in coal minesSonic Velocity
- 11➢ inverse of the alterability of rocks ➢ controlling not only the stability of slopes, surface and underground excavations but also that of a great number of stone structures, buildings and monuments.Durability
- 12change is reversible, elasticity, shale,milestoneELASTIC
- 13change is not reversible, ductility, clay,micaDUCTILE
- 14change is irreversible and the rock breaks, brittle, quartz,feldsparFRACTURE
- 15Other factors: ➢ Rate of Stress ➢ Temperature ➢ Confining PressureDeformation
- 16Pressed togetherCOMPRESSION
- 17Stretched apartTENSION
- 18Slips horizontallySHEAR
- 19➢ Stress cause Strain ➢ Strain results in StructureStress
- 20➢ amount of deformationStrain
- 21➢ existing competency of the rock fabric binding components. ➢ Laboratory Tests 1) Unconfined Compression Tests 2) Triaxial Compression Test 3) Splitting Tension Test 4) Beam Bending Test 5) Ring Shear testStrength
- 22Types of an EarthquakeTectonic, Volcanic, Explosive, collapse Earthquake
- 23➢ Seismology ➢ Seismic Waves ➢ vital information about the internal structure of the Earth ➢ SeismogramsSeismic Waves
- 24➢ Body Waves (P-waves and S-waves) ➢ Surface Waves (Rayleigh waves and Love waves)Seismic Waves
- 25➢ travel through the interior of the EarthBody Wave
- 26➢ Longitudinal Waves / Compressional Waves ➢ has greatest speed and appears first on seismograms ➢ Rigidity (↑ Rigidity, faster P-waves) ➢ Compressibility (↑ Compressibility, faster P-waves) ➢ Density (↑ Density, slower P-waves)➢ P-waves (Primary or Push-Pull or Pressure)
- 27➢ Transverse Waves ➢ less speed than P – waves ➢ Rigidity (↑ Rigidity, faster S-waves) ➢ Density ↑ Density, slower S-waves)➢ S-waves (Secondary or Shear or Shake)
- 28➢ along the surface of the Earth and the layers near the surfaceSurface Wave
- 29➢ Lord Rayleigh ➢ Combined effect of P- and S-waves on the earth’s surface ➢ Ground Roll / Rolling Waves➢ Rayleigh waves
(Surface Wave) - 30➢ Augustus Love ➢ Shearing sideways and then returning to its original form as each wave passes.➢ Love waves (L – Waves)
(Surface Wave) - 31➢ Physical Deformation ➢ Seismic Wave ➢ Speed ➢ Direction ➢ LocationSeismic Velocity
- 32– viscoelastic microplastic behavior of rocks➢ Elastic Moduli
- 33– Stress and Strains➢ Elastic Constant
- 34- deformation induced in a material by the application of a force➢ Static Method
- 35– measuring the ultrasonic body wave velocities➢ Dynamic method
- 36➢ injection of appropriate materials under pressure into certain parts of the earth's crust ➢ sealing of cracks in manmade structuresGrouting
- 37➢ increase the density of the soil ➢ rehabilitate settlement of sensitive structures➢Compaction Grouting
- 38➢ Soil exploration is a part of site investigation. ➢ deals with determining in general, the suitability of the site for the proposed construction.Site Investigation
- 39Objective ➢ The nature and sequence of strata ➢ The ground water conditions at the site ➢ The physical properties of soil and rock underlying the site ➢ The mechanical properties such as strength of different soil or rock strataSite Investigation
- 40Importance1. Minimize Damages
2. Saves on Cost
3. Determine Construction Costs
4. Increases Project Safety - 41Initial Information1. Type of Structure
2. Structure Characteristics
3. Starting Date
4. Construction Method
5. Estimated Construction Period
6. Soil condition (Geological, Geotechnical or Aerial Analysis)
7. Behavior of Existing Structures - 42➢ Retaining Walls FailureSite Investigation - Failures
- 43➢Settlement Failure (ex. Leaning Tower of Pisa)Site Investigation - Failures
- 44➢Sinkholes (Guatemala, 2007) (Guangzhou, China 2013)Site Investigation - Failures
- 45➢ first stage of site investigation ➢ researching the site to gain as much geological and historical information as possible1. Site Reconnaissance
- 46➢ General Site Exploration ➢ to obtain an approximate picture of sub-soil conditions at low cost. ➢Soil sample (experimental borings and shallow test pits) ➢ Simple laboratory tests (moisture content test, density, unconfined compressive strength test, etc.)2. Preliminary Site Exploration
- 47➢ Approximates values of soil's compressive strength. ➢ Position of the groundwater table. ➢ Depth and extent of soil strata. ➢ Soil composition. ➢ Depth of hard stratum from ground level. ➢ Engineering properties of soil ( disturbed sample)2. Preliminary Site Exploration
- 48➢ complex projects, major engineering works, heavy structures ➢ field tests (in-situ vane shear test, plate load test, etc.) ➢ laboratory tests (permeability tests, compressive strength test on undistracted soil samples)3. Detailed Site Exploration
- 49Report4. Preparation of Report
- 50➢ Permits visual inspection of subsurface conditions in natural state. ➢ Max. depth limited to 18 -20 feet. ➢ Especially useful for gravelly soil where boreholes may be difficult. ➢ Sampling/testing done on exposed surfaces.1) Open Excavation (Test Pits)
- 51➢ Simplest method of exploration and sampling. ➢ Power driven or hand operated. ➢ Max. depth 10 m ➢ Suitable in all soils above GWT but only in cohesive soil below GWT ➢ Hollow stem augers used for sampling or conducting Standard Penetration Tests.2) Methods of Boring
(Auger Borings) - 52➢ used for boring to a depth of about 10 to 30 m ➢ set with a drill rig can be used to obtain samples from deeper strata. ➢ Some rigs can be used to drill a hole to 100 m depth.2) Methods of Boring
(Power Auger) - 53➢ Casing is driven with a drop hammer ➢ Soil is loosened and removed from the borehole using water or a drilling mud jetted under pressure ➢ The water reaches the ground level where the soil in suspension is allowed to settle and mud is re-circulated.2) Methods of Boring
(Wash Boring) - 54➢ A heavy string of the drill rod is used for choking action ➢ suitable for boring holes of diameter 10cm, or more preferably 15 to20cm in most of the rocks ➢ depth of various strata can be detected by inspection of cuttings.2) Methods of Boring
(Rotary Drilling) - 55➢ done by alternatively lifting and dropping a heavy drilling bit that is attached to the lower end of the drilling which is attached to the cable ➢ The stroke of bit varies according to the ground condition ➢ 45-100 cm in depth with rate of 35-60 drops/min. ➢ It cannot detect thin strata2) Methods of Boring
(Percussion Drilling) - 56• Geological character and thickness of the strata • Channels • Materials • Induced seismicity, destruction of flora and fauna, resettlement of displaced people • Geological investigationsDams
- 57• Type and strength of the rock or soil • Presence of groundwater and its flow characteristics • Possibility of seismic activity • Potential for geological hazardsTunnel
- 581.Rock or soil type 2.Rock mass quality 3.Geological structures 4.Groundwater 5.Seismicity 6.Slope stability 7.Environmental considerationsTunnel
- 59Soil Formation1) Climate
2) Substrate
composition
3) Slope
steepness
4) Wetness
5) Time
6) Vegetation
type - 60➢ the solid rock that exists at some depth below the ground surfaceBedrock
- 61➢ made up of igneous, sedimentary, or metamorphic rock, and it often serves as the parent material for regolith and soil.Bedrock
- 62➢ – a bedrock depositOutcrop
- 63➢ – conspicuous forms bedrockCirques
- 64➢ shows the geological features of a certain regionGeologic Maps
- 65Geologic Maps1) Map
2) Explanation
3) Scale
4) Symbols
5) Correlation of map
units - 66• location of the well, the geology encountered, and water-table elevation.1) Well construction reports
(WCRs) - 67• to interpret the geometry and distribution of rock or sediment boundaries.2) Ground-penetrating radar
(GPR) - 68• measure physical properties of bedrock3) Aeromagnetic and gravity
surveys - 69• properties are displayed as a graph, with the depth of the well hole and the rock property4) Well logs
- 70• came from a hole drilled into the earth5) Rock cores
- 71Aerial Photo, Geologic Map, Geologic Map on satellite image6) Putting the information
together - 72• extensive interval of time occupied by the geologic history of Earth.Geologic Time
- 73▪ – longest portions: Phanerozoic Eon, Proterozoic Eon, Archean Eoneons
- 74▪ – 2nd longest portions: Eoarchean Era, Paleoarchean Era, Mesoarchean Era, Neoarchean Era, Paleoproterozoic Era, Mesoproterozoic Era, Neoproterozoic Era, Paleozoic Era, Mesozoic Era, Cenozoic Eraeras (‘erathem’)
- 75▪ – basic unit during the time specific systems of rocks were formedperiods
- 76▪ – unit during which a rock series is deposited ▪ agesepochs
- 77➢ Structures in the Earth's crust that have geological causes.Geological Structure
- 78➢ – study of the processes that result in the formation of geologic structures and how these structures affect rocks.Structural geology
- 79➢ Due to high pressure caused by tectonics ➢ Tunnel, foundation, or slope constructionFault
- 801) movement parallel to the dip of the fault planeDip-slip faults:
- 812) movement that is predominantly horizontal and parallel to the strike of the fault planeStrike-slip faults:
- 823) movement with both vertical and horizontal componentsOblique-slip faults:
- 83—
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- Flashcards on Geo M3, created by Cassy Rivera on 19/03/2025.
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- Cassy Rivera
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