foundations Flashcards
_____ is the members which provide support for the structure and its loads.
foundation
_____ is a connecting link between the superstructure and the soil in the ground.
foundation
What are the materials which will be used as foundation of structure?
concrete, steels, stones, bricks
Hard undisturbed rock in its native location of indefinitely great extent, not broken up by harmful cracks.
bedrock
The geological type of material composing ____ be such materials, as igneous, sedimentary, metamorphic rocks.
bedrock
In the design building foundations, what are the three essential steps needed?
- calculating the loads to be transmitted by the structure to the strata supporting
- determining the nature of the foundation beds that are to act as support
- designing the foundation structure to fit the conditions of loading and capacity of foundation bed
_______ are rarely due to faulty design of the foundation structure but rather to failure of the foundation beds to carry the loads put upon ot.
foundation failures
Foundation loads may be transmitted to the unconsolidated strata in two ways.
- constructing a continuous raft or spread footing or a system of stratum
- by forcing piles into the soil and joining uses structurally to the bearing column at the structures
What are the two factors that an engineer should consider in the construction of roads?
- geological condition which may affect the permanence of the roadboard, drainage, etc.
- kind of rock to be used for the road
What are the requisite condition for a reservoir site and dam site? (7-wnoaasa)
- water tight basin of ample size
- narrow outlet requiring a relatively small and economical dam having safe foundation
- opportunity for building a spillway to dispose the surplus water
- available materials for the construction of the dam
- assurance that the basic will not split up in too short time
- sufficient supply of water
- adequate reason to justify the cost of the project
In the examination of a reservoir site, an engineer should include the following:
examination of the rocks at the bottom and sides of the depressions
A study of depth of the deposition and depth of the water table, location of springs under discharge which may require the drilling of wells, underground stream, if possible, should be located.
exploration
____ is a geologic map which shows the types and the structure of the area or land mass.
topographic map
What are the methods of constructing piers? (3-oou)
- open cofferdam
- open dredging caissons
- use of compressed air-air caissons
____ consists of a single continuous wall on interlocking pilings, driven into the foundation strata.
open cofferdam
_______ represents substantial danger to humans and their works which may exist as consequences off natural events, but often they are the result of human activities.
geologic hazards
What are the four types of geologic hazards?
floods, slope failures, ground subsidence, earthquake
What are the causes of floods? (3-nhecbr)
- natural floods
- human activities
- earthquake
- construction in the river floodplain
- broken dam
- rapid icemelt
_____ occurs during or after heavy rainfall and snow melt.
natural floods
_____ increases the incidence of flooding.
human activities
What are ways of flood control? (5-fcdcf)
- floodplain zoning
- constructions in high elevations
- diking to contain water
- channel straightening and lining
- flood-control dams
____ affords the best protection against flooding.
floodplain zoning
_____ as a necessary solution for many rapidly growing cities which are greatly affected by natural and development changes.
diking to contain water
_____ is a solution often applied to small rivers and streams to increase the flow velocity and reduce the flood hazard and bank erosion.
channel straightening and lining
_____ constructed upstream service as a storage reservoir and are the most effective construction solution to flood protection.
flood-control dams
What are the classifications of slope failures?
creep, flow, slides, fall, avalanche and landslides
What are the factors affecting slope failures? (4-tgws)
- topography
- geology
- weather
- seismic activity
What are causes of slope failure or slide? (4-girg)
- gravity of the weight of the slope materials which have saturated by water
- increase in gravity and decrease in shearing strength acting together of the soil and rocks present along the slopes
- removal of the lateral support particularly the removal of the toe of the slope emplacement of building or highway
- ground movements cause by volcanic and tectonic movement like earthquake
What are the methods of controlling slides? (3-ccp)
- change the slope geometry to decrease the driving forces or increase the resisting forces by removal of very large volume of loose materials or debris along the top and side of the slopes
- control surface water infiltration to reduce seepage forces
- planting the slope with thick, fast growing native vegetation and should be applied with burlaps bags and sprayed with mulch to increase growth
_____ is the sinking or downward settling of the ground surface resulting from the settlement of native low density soils, or the caving in of natural or man-made underground voids.
ground subsidence
_____ is the downward vertical movement of the ground or soil due to changes in stresses within the earth, often cause by the settlement load in the surface.
settlement or collapse
What are the cause of ground subsidence? (4 - eepe)
- extraction of fluid or solids
- erosion
- physicochemical changes
- earthquakes or tectonic movements
What are the causes of ground settlement? (5-lmdui)
- lowering of the groundwater
- migration of soils fines
- deep voids
- underground excavation
- induced ground vibration and seismic events
What are the sources of earthquakes? (4- vtmm)
- volcanic eruptions
- tectonic movements
- minor earth shaking
- man-made disturbances
____ is the point where the earthquake starts or originates.
focus
____ is the point on the surface of the earth directly above the focus.
epicenter
_____ is the measure of the earthquake and remains unchanged with distance from earthquake.
magnitude
____ is the amount of energy released at the earthquake source.
magnitude
_____ is the degree or amount of shaking caused by an earthquake at a given place and decreases with distance from the earthquake epicenter.
intensity
What are the effects of earthquakes? (8-cdfgstfa)
- collapse of manmade structures
- disruption of utilities
- fires cause by short circuits
- ground subsidence and settlement
- slope failures
- tsunamis
- floods
- avalanches and landslides
____ is structure which prevents the flow of water and accumulates it is a reservoir.
dams
_____ is an open channel that generally consists of an inlet channel and an exit channel.
spillways
____ is a subsurface body of rock having sufficient porosity and permeability to store and transmit fluids.
reservoir
Exploration of foundation site: things to be considered before the site of an important structure is selected:
- knowledge of the geology of the size is of great importance before it is finally selected
- after the geologist has made a general reconnaissance of the area to be surveyed, he examines all exposures of solid rock, noting and recording his observations for incorporation in the geologic map
What consists the geologic map?
topographic map into which are indicated the types and the structures of the area
Why must underground exploratory work be accomplished?
rarely will a geological survey alone provide sufficient reliable information with regards to underground conditions of the foundation.
The following suggestions may be useful with regards to underground exploratory work:
- no boreholes should be driven before a general geological survey of the area has been made
- boreholes should be located in relation to the local geologic structures in order to obtain as much information of the geology of the area as possible
- in exploring superficial deposits, at least one borehole should be carried to a rock
For structures as pavements, small buildings, retaining walls, and small tanks, shallow explorations are probably sufficient. This may involve any or all of the following techniques: (3)
- drilling a pipe or road a few feet into the ground with a sledge hammer
- by drilling holes with an unusual welded at the end of the pipe in which sample of the soil may stick to the auger
- test pits enable one to examine the materials in their natural stage, to judge their firmness by the resistance to digging, and to see first-hand what the ground water conditions are
____ are characterized by a sudden dislodgment of single or multiple blocks of soil or rock which fall in free descent.
falls
_____ is caused by the undercutting of slopes due to stream or wave erosion, usually assisted by seepage forces.
falls
____ is the act, process, or fact of moving from a higher to a lower position.
descent
_____ are characterized by a slow to fast movement of soil and rocks along some well defined planar failure surface.
slides
_____ are rapid to very rapid movement of incoherent mass of rock or soil debris wherein the original structure of the formation is no longer discernable, occurring an ill-defined surface.
avalanches and landslides
____ is caused by hydraulic excavation during intense storms.
avalanches and landslides
_____ are characterized by soil or soil-rock debris moving as a viscous fluid or slurry usually terminating at distances far beyond the failure zone. This is caused quite similar to avalanches.
flows
_____ are characterized by a slow, imperceptible downslope movement of slope materials under low stress levels, which normally affects only the shallow portion of the slope, but it can be deep-seated where a weak zone exists.
creep
_____ is an unconsolidated and consolidated mantle beneath the earth’s crust where it can support lands of vegetation.
soil
____ is a vertical section of the soil that depicts all of its horizons.
soil profile
What are the types of soil deposits? (5)
glacial deposit, beach deposit, river deposit, wind deposit, gravity deposit
