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    Site Investigation and Laboratory Testing

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    hiran peiris
    The document discusses site investigation and laboratory testing for dam construction projects. It describes selecting suitable dam sites based on factors like foundation conditions, topography, geology, and availability of construction materials. Key site investigation methods are described, including test pits, boreholes, and laboratory testing of soil and rock samples to evaluate properties. Construction monitoring considerations are also outlined, such as testing borrow materials, conducting proctor tests, and ensuring proper compaction of earthen structures.

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    Site Investigation and Laboratory Testing

    Uploaded by

    hiran peiris
    24 views14 pages
    The document discusses site investigation and laboratory testing for dam construction projects. It describes selecting suitable dam sites based on factors like foundation conditions, topography, geology, and availability of construction materials. Key site investigation methods are described, including test pits, boreholes, and laboratory testing of soil and rock samples to evaluate properties. Construction monitoring considerations are also outlined, such as testing borrow materials, conducting proctor tests, and ensuring proper compaction of earthen structures.

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    SITE INVESTIGATION AND LABORATORY TESTING.pptx

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    The document discusses site investigation and laboratory testing for dam construction projects. It describes selecting suitable dam sites based on factors like foundation conditions, topography, geology, and availability of construction materials. Key site investigation methods are described, including test pits, boreholes, and laboratory testing of soil and rock samples to evaluate properties. Construction monitoring considerations are also outlined, such as testing borrow materials, conducting proctor tests, and ensuring proper compaction of earthen structures.

    Copyright:

    © All Rights Reserved
    Download as PPTX, PDF, TXT or read online from Scribd
    Download as pptx, pdf, or txt
    24 views14 pages

    Site Investigation and Laboratory Testing

    Uploaded by

    hiran peiris
    The document discusses site investigation and laboratory testing for dam construction projects. It describes selecting suitable dam sites based on factors like foundation conditions, topography, geology, and availability of construction materials. Key site investigation methods are described, including test pits, boreholes, and laboratory testing of soil and rock samples to evaluate properties. Construction monitoring considerations are also outlined, such as testing borrow materials, conducting proctor tests, and ensuring proper compaction of earthen structures.

    Copyright:

    © All Rights Reserved
    Download as PPTX, PDF, TXT or read online from Scribd
    Download as pptx, pdf, or txt
    of 14

    SITE INVESTIGATION AND

    LABORATORY TESTING
    Dams
    • Dams are barriers constructed across a river
    valley to impound water.
    • Dams are built mainly for controlling floods,
    irrigation, electricity generation and for urban
    water supply.
    • Dams may be constructed for a specific use or it
    may be ‘multipurpose’ which serves more than
    one use
    • Dams are generally classified according to its
    use, hydraulic design, construction design and
    material used in it
    Selection of Site for Dam
    The following are the requisite of good sites for
    dam.
    • Foundation:-
    • Topography:-
    • Site of Spillway :-
    • Material:-
    • Reservoir and catchment area:
    • Communication:-
    • Locality:
    Site investigation for dam site
    1. Topography
    Topography in large measures dictates a first
    choice of dams. Generally a dam site is ideal
    where a valley is constricted with steep rock
    slopes.
    2. Geology and foundation condition
    Foundation condition depend upon the
    geological character and thickness of the strata
    which are to carry the weight of the dam
    The most common methods of observing the
    soils below the surface, obtaining samples and
    determining physical properties of the soils and
    rocks include
    • excavation of test pits/trenches using a
    backhoe and various sized excavators
    • hand augers
    • drilling/boring, i.e. rotary, hollow-stem auger,
    continuousflight auger.
    SITE INVESTIGATION

    • The rock should be sound and resistant to the


    expected static and dynamic forces including
    earthquakes.
    • The valley slope should be stable when the
    reservoir is full. This requirement also applies to
    the rock abutments.
    • The foundation of the dam should be safe from
    sliding, especially in the case of gravity dam.
    • The rock used for the foundation should be of
    one geologic classification to avoid variations in
    the values of modulus of elasticity.
    • The foundation and the reservoir wall should
    be water tight.
    • The rock at the site should be resistant to
    solution, erosion, decomposition and other
    detriment effects of wetting and drying
    freezing and thawing.
    • The reservoir drainage area including rocks
    and overburden should be resistant to erosion
    and therefore not likely to contribute such
    heavy silt loads to the reservoir.
    • The geology and topographic conditions
    should permit favorably for the location of
    spillways and diversion tunnel, power house
    and outlet conduits
    • The location of construction materials
    particularly concrete aggregate should be with
    in an economically justified distances.
    Construction Monitoring

    MATERIALS
    Grain size distribution analysis of materials
    • Core, filters, drains
    • Make sure material installed meets
    specifications
    • Make sure that the borrow materials do not
    change…
    MATERIAL tests

    • Triaxial extension/shear – filter and core


    • Consolidation
    • Hydraulic conductivity

    Lab tests
    • filters - Constant or falling head
    • core – triaxial

    Field clay
    • Double ring infiltrometer
    • Centrifuge permeanometer
    Proctor Tests
    • Source materials in borrow pit
    • Materials hauled to site
    Field Compaction
    • Uncompacted layer thickness (300mm max)
    • Compaction equipment is suitable
    • Moisture content and Maximum dry density
    # Nuclear Density, sand cone, rubberballoon
    # Make sure Nuclear density is calibrated
    COMPACTION
    Place loose soil in the field and compact it to
    make soil strong as possible
    • Maximum shear strength
    • Very little settlement
    • Low hydraulic conductivity

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