44431662 Ensayo de Penetracion Estandar Spt

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SOIL ANALYSIS STANDARDPENETRATION TEST (SPT)

Paulo Cesar Garrido

UNIVERSIDAD SAN CARLOS DE GUATEMALFACULTAD DE INGENIERIA CIVIL

11/10/2011


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INTRODUCTIONAll civil works are based on the soil of one formor another, and many also use the land as alandfill construction in general, so, consequently,

its stability and behavior will be functional andaesthetic determined, among other factors, theperformance of the seat material located withinthe depths of influence of the efforts that aregenerated, or the shape of land used for landfill.

Standard penetration test (SPT)


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METHODS OF SOIL

ANALYSIS1 ... Rock and soil2 ... Methods of preliminary exploration

3 ... Method of standard penetration

4 ... cone penetration method

5 ... rock revolving Methods

6 Geophysical Methods



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STANDARD PENETRATIONTEST (SPT)

is the best results because we provide more informationabout groundwater, unlike previous methods which onlygives us a description. Depend on soil type and give usdifferent results, for example if we get the fractional soilcompactness of the robes, if you have a plastic floorknow the resistance of the simple compression. Thismethod gives us disturbed samples which allow itsstudy.


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SPT TEST OBJECTIVES

Getting the measure of the resistance to

penetration with a sampler in a cohesive soilRepresentative samples of soil

Find correlation between:The # of hits, N, measured and compactness,

and simple compression strength through existingtables or abacus.



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QUIPMENT1. Drilling Equipment

STANDARD PENETRATION TEST (SPT)

Penetrometer tube Penetrometer in the hole used as a jacketliner


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EQUIPMENT2. Sampling rods



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EQUIPMENT

3. sampler tube



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EQUIPMENT4. 140lbs ram. weight system with fall


Rig, the hammer is at its highest point to be driven The hammer comes down to hit the penetrometerwhich is inside the well.


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TEST PROCEDURE

The trial itself is party to sink the pipe to penetrate30 cm (1 ft) on the ground, aided by a hammerweighing 140 lbs and a height of 75 cm drop,counting the number of hits "N".



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TEST PROCEDURE

1. For the test the sampler is screwed to the end ofthe drill pipe and down into the deep mantle wherethe sand on which it will do the test. Downholepreviously must have been carefully cleaned toensure that the material is not altered.



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TEST PROCEDURE

2. Place the hammer in position guided by the drillpipe, lifting it with a cable operated manually ormechanically, which is suspended from the tripodwith pulley



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TEST PROCEDURE

3. It marks the upper end of the drill pipe into threeparts, each of 15 cm for further observation of theprogress of the sampler under the impact of thehammer.



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TEST PROCEDURE

4. He drops the hammer on the stubborn drill pipe andcounts the number of strokes applied with thespecified drop height for each 15 cm segmentmarked. No account is taken hits for the firstsegment because it is the initial penetration to the

ground. Applied beatings are added to penetrate thetube in the second and third segment, thus obtainingthe value of "N".



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TEST PROCEDURE

5. It brings to the surface and opens the sampler;should record the length of the sample recovered,weight, and describe their characteristics in terms ofcolor, uniformity etc.


(


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TEST PROCEDURE

5. It brings to the surface and opens the sampler;should record the length of the sample recovered,weight, and describe their characteristics in terms ofcolor, uniformity etc.

STANDARD PENETRATION TEST (SPT

Repeat the above steps as necessary to determine the variationof strength parameters with depth or the number of strata.



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TEST PROCEDURE

The test is applicable only to sandy soils.If there is a blanket of sand content record low, only one of

them may invalidate the test.In very fine sands located below the water table the value of "N"should be corrected because it would be higher than given by adry sand, due to the low permeability of the latter, whichprevents the water migrates through the gaps to occur impact.

Empirically it was found that in these cases the value of N canbe corrected by the following expression applies when thepenetration is greater than 15 blows sand and saturated.


Please note the following:

N = 15 + 1/2 ( N - 15 )N:corrected value and penetration rateN: value obtained in the trial.

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44431662 Ensayo de Penetracion Estandar Spt