Clase de laboratorio 03: Compactación de suelos

Mecánica de Suelos y GeologíaFacultad de Ingeniería, Universidad de Buenos Aires

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Compaction Test Using Standard Effort 213

energy per unit volume, it is recognized that the results do vary slightly with specimen size and geometry of hammer.

A compaction test is sometimes referred to as a “ Proctor, ” as in Standard Proctor or Modifi ed Proctor. The name is in recognition of R. R. Proctor ( 1933 ), who performed a tremendous amount of work to determine compaction properties.

The procedure for performing a compaction test according to D698 and D1557 requires a measure of the oversize fraction in order to select the appropriate mold size and number of drops per layer. The fi rst step is to estimate which method would be most likely and then to separate the material on the appropriate sieve (4.75 mm, 9.5 mm, or 19 mm). While a material meeting the limitation of Method A will also meet limitations of the other two methods, it is not permissible to use Method B or C unless so specifi ed by the requesting agency.

In most cases, a grain size analysis will be performed along with the compaction test. It is most effi cient to process and separate the material for both tests at the same time using one of these sizes as the Designated A sieve as discussed in Chapter 8 for the composite sieve analysis.

As with previous tests, if fi nes are present the material should not be oven - dried prior to compaction. The total mass of the sample is obtained along with the portion of coarser and fi ner fractions in the moist condition. The oversize percentage can be estimated immediately using these mass measurements (and then fi nalized after the grain size analysis has been performed), eliminating any delay in proceeding with the compaction test. Blend the fi ner fraction and estimate the initial water content and the optimum water content. Experience with compaction and with the specifi c material is

Figure 12.3 24.5 N (5.5 lbf) compaction hammer, 101.6 mm (4 in.) and 152.4 mm (6 in.) diameter molds with collars used to perform ASTM D698. Also pictured is a straight edge used to square off the top of the specimen.

Method Mold DiameterMaterial used in Specimen

Number of Blows per Layer

Maximum Particle Size Limitations

Method A 101.6 mm (4 in) Fraction passing the 4.75 mm (No. 4) sieve

25 25% or less retained on the 4.75 mm (No. 4) sieve

Method B 101.6 mm (4 in) Fraction passing the 9.5 mm (3/8 in) sieve

25 25% or less retained on the 9.5 mm (3/8 in) sieve

Method C 152.4 mm (6 in) Fraction passing the 19 mm (3/4 in) sieve

56 30% or less retained on the 19 mm (3/4 in) sieve

Table 12.1 Table of mold size, number of blows per layer, mate-rial used, and material limitations for the various methods in ASTM 698 and ASTM D1557. (Adapted from ASTM D1557-07)

Índice

• Compactación Proctor estándar y modificado• Propiedades de los suelos compactados• Ensayo CBR• Control densidad in situ• Proyecto investigación LMS-FIUBA: Estudio de mezclas

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Procedimiento de ensayo Proctor

• Se prepara suelo previamente tamizado con humedad uniforme

• Se coloca la primera capa y se apisona con golpes de caída de martillo estándar

• Se repite en las demás capas del molde• Se enrasa ambas superficies• Se mide peso unitario y humedad ! , "• Se calcula peso unitario seco !#• Se repite el procedimiento hasta obtener

por lo menos 5 pares de valores ! , "• Se determina la curva de compactación3

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Moldes y martillo

estándar

Ensayo Proctor estándar (T-99)

• Método A (20% o menos del material es ret. #4)– Molde 4”, suelo pasante #4 (4.75mm)– 3 capas de 25 golpes, martillo 2.5kg, h=30cm

• Método B (>20% ret. #4 y el 20% o menos ret. 3/8”)– Molde 4”, suelo pasante 3/8” (9.5mm)– 3 capas de 25 golpes, martillo 2.5kg, h=30cm

• Método C (>20% ret. 3/8” y el 30% o menos ret. 3/4”)– Molde 6”, suelo pasante 3/4” (19mm)– 3 capas de 56 golpes, martillo 2.5kg, h=30cm

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4 ¿Qué método utilizar? R: Depende del suelo a ensayar

Ensayo Proctor modificado (T-180)

• Método A (20% o menos del material es ret. #4)– Molde 4”, suelo pasante #4 (4.75mm)– 5 capas de 25 golpes, martillo 4.5kg, h=45cm

• Método B (>20% ret. #4 y el 20% o menos ret. 3/8”)– Molde 4”, suelo pasante 3/8” (9.5mm)– 5 capas de 25 golpes, martillo 4.5kg, h=45cm

• Método C (>20% ret. 3/8” y el 30% o menos ret. 3/4”)– Molde 6”, suelo pasante 3/4” (19mm)– 5 capas de 56 golpes, martillo 4.5kg, h=45cm

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5 ¿Qué método utilizar? R: Depende del suelo a ensayar

dg

cw

Proctor Modificado

Proctor Standard

opNwopMw

Mmaxg

Nm axg

Curvas de compactación Proctor

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Figura. II.16. Equipo de control mediante electrodos (Nobuma-sa et al 2003).

6.3.2 Nucleodensímetro Mediante la medición de la absorción de de isótopos radiactivos se puede estimar el peso unitario y la humedad del terreno, previa calibración en un terra-plén del mismo suelo con peso unitario conocido. Este método es rápido y eficiente, pero es costoso porque involucra materiales potencialmente peligro-sos y contaminantes que requieren permisos especia-les de manipulación. En la figura II.17 se muestra un nucleodensímetro.

Figura II.17. Nucleodensímetro.

6.3.3 Carga dinámica Aplicando una carga sinusoidal a la superficie de la capa compactada y midiendo su respuesta dinámica se puede obtener el modulo de elasticidad, que se correlaciona con el grado de compactación previa calibración en un terraplén del mismo suelo con pe-so unitario conocido. Es un método sencillo, rápido y no requiere especialización. En la figura II.18 se muestra un equipo de control de compactación me-diante carga dinámica.

Figura II.18. Equipo de control mediante carga dinámica.

7 RELACIONES HUMEDAD – PESO UNITARIO

Los suelos cohesivos presentan características dife-rentes si fueron compactados con humedades mayo-res o menores que la óptima. Se observan diferencias de permeabilidad, orientación de las partículas, compresibilidad y variaciones volumétricas.

7.1 Estructura de los suelos compactados del lado seco del óptimo

La rigidez de un suelo compactado con una hume-dad menor que la óptima es mayor que la que mues-tra el mismo suelo a la misma densidad, compactado con una humedad mayor que la óptima.

Para bajas humedades, la concentración de carga en las caras de las partículas generan repulsión y tendencia al hinchamiento. A su vez la succión es al-ta, lo que favorece el desarrollo de una estructura desorientada.

7.2 Estructura de los suelos compactados del lado húmedo del óptimo

Si se compacta con una humedad superior a la ópti-ma, la forma de compactación tiene influencia en la estructura, compresibilidad y resistencia del suelo.

La compactación con humedades mayores que la óptima permite obtener un material de comporta-miento más dúctil que permite una mayor capacidad de adaptación a los asentamientos.

La estructura en este caso resulta más orientada. Se presume que las partículas comienzan a orientar-se a medida que se aumenta la humedad porque las fuerzas de repulsión y capilares disminuyen con un mayor contenido de humedad.

Aumentando la energía de compactación a hume-dad constante, también se produce el mismo efecto.

En la Figura II.19 se esquematiza la estructura de un suelo cohesivo compactado del lado seco y húmedo.

Figura II.19. Estructura dispersa que se obtiene cuando se compacta del lado seco del óptimo y orientada del lado húmedo del óptimo.

7.3 Compactación alcanzable El peso unitario seco de un suelo con un determina-do contenido de humedad aumenta con la energía de

13

Figura. II.16. Equipo de control mediante electrodos (Nobuma-sa et al 2003).

6.3.2 Nucleodensímetro Mediante la medición de la absorción de de isótopos radiactivos se puede estimar el peso unitario y la humedad del terreno, previa calibración en un terra-plén del mismo suelo con peso unitario conocido. Este método es rápido y eficiente, pero es costoso porque involucra materiales potencialmente peligro-sos y contaminantes que requieren permisos especia-les de manipulación. En la figura II.17 se muestra un nucleodensímetro.

Figura II.17. Nucleodensímetro.

6.3.3 Carga dinámica Aplicando una carga sinusoidal a la superficie de la capa compactada y midiendo su respuesta dinámica se puede obtener el modulo de elasticidad, que se correlaciona con el grado de compactación previa calibración en un terraplén del mismo suelo con pe-so unitario conocido. Es un método sencillo, rápido y no requiere especialización. En la figura II.18 se muestra un equipo de control de compactación me-diante carga dinámica.

Figura II.18. Equipo de control mediante carga dinámica.

7 RELACIONES HUMEDAD – PESO UNITARIO

Los suelos cohesivos presentan características dife-rentes si fueron compactados con humedades mayo-res o menores que la óptima. Se observan diferencias de permeabilidad, orientación de las partículas, compresibilidad y variaciones volumétricas.

7.1 Estructura de los suelos compactados del lado seco del óptimo

La rigidez de un suelo compactado con una hume-dad menor que la óptima es mayor que la que mues-tra el mismo suelo a la misma densidad, compactado con una humedad mayor que la óptima.

Para bajas humedades, la concentración de carga en las caras de las partículas generan repulsión y tendencia al hinchamiento. A su vez la succión es al-ta, lo que favorece el desarrollo de una estructura desorientada.

7.2 Estructura de los suelos compactados del lado húmedo del óptimo

Si se compacta con una humedad superior a la ópti-ma, la forma de compactación tiene influencia en la estructura, compresibilidad y resistencia del suelo.

La compactación con humedades mayores que la óptima permite obtener un material de comporta-miento más dúctil que permite una mayor capacidad de adaptación a los asentamientos.

La estructura en este caso resulta más orientada. Se presume que las partículas comienzan a orientar-se a medida que se aumenta la humedad porque las fuerzas de repulsión y capilares disminuyen con un mayor contenido de humedad.

Aumentando la energía de compactación a hume-dad constante, también se produce el mismo efecto.

En la Figura II.19 se esquematiza la estructura de un suelo cohesivo compactado del lado seco y húmedo.

Figura II.19. Estructura dispersa que se obtiene cuando se compacta del lado seco del óptimo y orientada del lado húmedo del óptimo.

7.3 Compactación alcanzable El peso unitario seco de un suelo con un determina-do contenido de humedad aumenta con la energía de

floculenta dispersa

R. Proctor

Ensayo Proctor: interpretación de curvaLa

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soil grains per unit volume of soil. Consequently, the dry unit weight decreases. The modifi ed Proctor test, using higher levels of compaction energy, achieves a higher maximum dry unit weight at a lower optimum water content than the standard test (Figure 5.5). The degree of saturation is also lower at higher levels of compaction than in the standard compaction test.

The soil is invariably unsaturated at the maximum dry unit weight, that is, S , 1. We can determine the degree of saturation at the maximum dry unit weight using Equation (5.1). We know gd 5 (gd)max and w 5 wopt from our Proctor test results. If Gs is known, we can solve Equation (5.1) for S. If Gs is unknown, you can substitute a value of 2.7 with little resulting error in most cases.

What’s next . . . In the next section, you will learn how to interpret the Proctor test for practical applications.

5.5 INTERPRETATION OF PROCTOR TEST RESULTS

Knowledge of the optimum water content and the maximum dry unit weight of soils is very important for construction specifi cations of soil improvement by compaction. Specifi cations for earth structures (embankments, footings, etc.) usually call for a minimum of 95% of Proctor maximum dry unit weight. This level of compaction can be attained at two water contents—one before the attainment of the maxi-mum dry unit weight, or dry of optimum, the other after attainment of the maximum dry unit weight, or wet of optimum (Figure 5.6). Normal practice is to compact the soil dry of optimum. Compact the soil wet of optimum for swelling (expansive) soils, soil liners for solid waste landfi lls, and projects where soil volume changes from changes in moisture conditions are intolerable.

5.5 INTERPRETATION OF PROCTOR TEST RESULTS 91

FIGURE 5.5Effect of increasing compaction efforts on the dry unit weight–water content relationship.

Dry

uni

t w

eigh

t

Water content

Line of optimum water content

Increasing compaction

FIGURE 5.6 Illustration of compaction specifi cation of soils in the fi eld.

Water content

95% Maximum dryunit weight

Acceptable range ofdry unit weight

Wet of optimumSoils with large volume changesfrom changes in water content, e.g.,expansive and collapsible soils.

Soils with small volume changes fromchanges in water content, e.g., granularsoils, clayey-sand, sandy clay.

Dry of optimum

Dry

uni

t w

eigh

t

Acceptable rangeof water content

c05SoilCompaction.indd Page 91 9/10/10 1:18:27 PM user-f391c05SoilCompaction.indd Page 91 9/10/10 1:18:27 PM user-f391 /Users/user-f391/Desktop/Ravindra_10.09.10/JWCL339:203:Buddhu/Users/user-f391/Desktop/Ravindra_10.09.10/JWCL339:203:Buddhu

Rama seca

(Budhu M., Soil Mechanics & Foundations)

Rama húmeda

95% $!"á$

Contenido aceptable de humedad %%&' ± 2 − 3%

Humedad

Peso

uni

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sec

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Valores aceptables $!

Zona de compactación aceptable para suelos con grandes cambios

volumétricos por ∆%

Zona de compactación aceptable para suelos con pequeños cambios

volumétricos por ∆%

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220 Geotechnical Laboratory Measurements for Engineers

1. Determine the mass of the sample mold and mold base to the nearest gram. Do not include the collar.

2. Measure the mold depth (3 places) and mold diameter (6 places) to ! 0.02 mm.

3. Check hammer for damage, square edges, proper mass, and proper drop height.

Using a well - graded sand with less than 5 percent fi nes eases the process of laboratory instruction. These procedures assume such a material is being used. Select material with oversize particles only if it will be desired to demonstrate those aspects of the test.

1. Select enough of the moist material to provide about 12 kg of dry soil.

2. Obtain the natural water content.

3. Estimate how much material is required for each compaction point and prepare fi ve samples having water contents separated by about 1.5 percent. Adjust the water contents such that they bracket the optimum value.

4. Temper the soil overnight. For laboratory instruction purposes, it may be necessary to skip this step; however, not tempering soils may increase the scatter in the data and make it more diffi cult to defi ne the compaction curve.

The compaction test will be performed in general accordance with ASTM Standard Test Method D698, although D1557 can be used instead with minor modifi cations.

1. Assemble the mold and clamp to the solid base or fl oor.

2. Compact each specimen in three equal layers using 25 blows per layer.

3. Before compacting the second and third layers, scarify the top surface of the under-lying layer with a knife to about 3 mm depth.

C A L I B R AT I O N

S P E C I M E N P R E PA R AT I O N

Soilρmax (Mg/m3)

ωopt (%) Method

Maine Clay* 1.80 17.7 Harvard Miniature

Vicksburg Buckshot Clay** 1.56 22.8 D698

Annapolis Clay** 1.75 16.6 D698

Vicksburg Silt** 1.70 17.1 D698

Well-graded clean gravels, gravel-sand mixtures***

2.0 to 2.2 8 to 11 D698

Poorly graded clean gravels, gravel-sand mix***

1.8 to 2.0 11 to 14 D698

Silty gravels, poorly graded gravel-sand-silt***

1.9 to 2.2 8 to 12 D698

Clayey gravels, poorly graded gravel-sand-clay***

1.8 to 2.1 9 to 14 D698

Well-graded clean sands, gravelly sands***

1.8 to 2.1 9 to 16 D698

Poorly graded clean sands, sand-gravel mix***

1.6 to 1.9 12 to 21 D698

Silty sands, poorly graded sand-silt mix***

1.8 to 2.0 11 to 16 D698

*Unpublished laboratory data.**After ASTM D698; values converted from pounds per cubic foot (pcf) to megagrams per cubic meter (Mg/m3).***After Naval Facilities Engineering Command (1986), Design Manual: 7.02; values converted from pcf to Mg/m3.

Table 12.2 Typical values of the maximum dry density and optimum moisture content.

P R O C E D U R E

(Germaine J. – Geotechnical Laboratoy)

$+,á. Norma ASTM Proctor estándar

Inspección tacto-visual

• Ejemplo 1: Gravas angulares con presencia de arenas y finos no plásticos, con presencia de mineral de yeso.

• Ejemplo 2: Arcilla plástica uniforme, blanda, con presencia de restos de conchillas marinas en forma errática.

• Ejemplo 3: Limo no plástico, parcialmente cementado.

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Incidencia del nivel de compactación y humedad en la conductividad hidráulica

• Hasta 3 órdenes de magnitud en el valor de $

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CO

E o

10"

10"

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'•5 1 0

3 "D c o o

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-7

10"

10' High Effort

10 15 20 25 Molding Water Content (%)

(a)

O Q.

"(D

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i K i i

Low Compactive Effort

10 15 20 25

Molding Water Content (%) (b)

FIG. 2. Data from Mitchell et al. (1965) for Silty Clay Compacted with Impact Compaction: (a) Hydraulic Conductivity versus Molding Water Content; (b) Com-paction Curve (1 pcf = 0.157 kN/m3)

and shear strength as shown in Fig. 6. The acceptable zone in Fig. 6 applies to P = 95% and an acceptable water content 0-4% wet of optimum. All w-"id points contained within the acceptable zone correspond to test specimens with t s l x 10~7 cm/s, but the shape and boundaries of the acceptable zone in Fig. 6 correlate with neither hydraulic conductivity nor shear strength.

Shear strength and hydraulic conductivity are not the only parameters that concern the engineer who designs soil liners and covers; potential for desic-

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Contenido de humedad (%)

Peso

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tario

sec

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cf)

Bajo nivel compactación

Alto

Medio

CO

E o

10"

10"

10

'•5 1 0

3 "D c o o

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-7

10"

10' High Effort

10 15 20 25 Molding Water Content (%)

(a)

O Q.

"(D

120

110 -

c 10° Z> >> Q 90

i K i i

Low Compactive Effort

10 15 20 25

Molding Water Content (%) (b)

FIG. 2. Data from Mitchell et al. (1965) for Silty Clay Compacted with Impact Compaction: (a) Hydraulic Conductivity versus Molding Water Content; (b) Com-paction Curve (1 pcf = 0.157 kN/m3)

and shear strength as shown in Fig. 6. The acceptable zone in Fig. 6 applies to P = 95% and an acceptable water content 0-4% wet of optimum. All w-"id points contained within the acceptable zone correspond to test specimens with t s l x 10~7 cm/s, but the shape and boundaries of the acceptable zone in Fig. 6 correlate with neither hydraulic conductivity nor shear strength.

Shear strength and hydraulic conductivity are not the only parameters that concern the engineer who designs soil liners and covers; potential for desic-

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Contenido de humedad (%)

Cond

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(cm

/seg

)Alta compactación

Bajo

Medio

(Mitchell et al, 1965)

Incidencia de la reutilización del suelo en la curva de compactación

• Se debe efectuar cada punto experimental de la curva con suelo original. El material usado se descarta.

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218 Geotechnical Laboratory Measurements for Engineers

soils will have different scales, but the relative positions of the curves with increasing water content should remain about the same.

Reusing material causes a considerable increase in the dry density achieved at a particular water content. Previously compacted fi ne - grained materials will clump. Coarse - grained materials will experience particle crushing during compaction. Reus-ing material will affect the shape of the curve and the resulting interpretation of the maximum dry density. A schematic comparison between using completely new material versus reusing the same material for each point is shown in Figure 12.9 . For the plot of the reused material, the driest point is compacted fi rst, and then the same material is reused for each successively wetter point.

Other important considerations for determining compaction characteristics include:

The compaction properties of some soils are sensitive to drying and there-fore soils should not be dried prior to performing a compaction test unless it can be shown that the results are independent of drying. The fi ne fraction of soils should not be oven - dried prior to compaction. It is important to note that air - drying is not precluded in test methods D698 and D1557; however, the moist method is the preferred specimen preparation method and a warning is given concerning possible altering soil properties by air - drying. Make sure the material is homogeneous across the portions. Use the blending and splitting procedures described in Chapter 1 to obtain the testing specimens. Temper soils that contain fi ne - grained materials. Refer to Table 9.2 in Chapter 9 , “ Atterberg Limits ” for suggested tempering times according to USCS group classifi cation. Secure the mold to a solid base prior to imparting energy. Make sure the solid base has a mass of at least 100 kg, and the mold is securely attached using devices such as clamps. The surface of the base shall be level, and fl at such that the compaction mold is fully supported and does not tilt or translate during application of compaction energy. Make sure the layers have approximately the same volume to distribute the energy, and that each layer is spread out evenly across the mold. Compact each layer using the sequence of hammer drops shown in Figure 12.10 to ensure uniform energy for the 101.6 mm (4 in.) diameter mold or Figure 12.11 for the 152.4 mm (6 in.) diameter mold. After compaction, the surface of each layer should be relatively fl at. If sig-nifi cant unevenness occurs, adjust the tamping pattern to obtain a fl at surface. Note that pumping may occur at water contents above optimum, particularly for fi ne - grained soils.

•

•

•

•

•

•

•

S ! 100%

New

Reused

ωc

ρ d

4

3

21

5

7

8

6

and so on

Figure 12.9 Effect of reusing material on the position of the compaction curve.

Figure 12.10 Hammer drop pattern when using the 101.6 mm (4 in.) diameter mold.

$ +

suelo reutilizado

suelo original

Incidencia del nivel de compactación y humedad en la estructuración de suelos

• A mayor ", tendencia a formar estructura dispersa • A mayor nivel de compactación y misma ", tendencia a

formar estructura dispersa, tanto en RS como en RH

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11 (Lambe 1958)contenido de humedad

dens

idad

seca

Energía de compactación alta

Energía de compactación baja

floculenta

dispersa

Prueba CBR laboratorio(California Bearing Ratio)

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• Se conoce previamente la curva Proctor• Se compacta el suelo en molde 6” con

valores !# , " predefinidos.• Se inunda la muestra durante 96hs bajo

carga y se mide la deformaciónconstante sobre muestra compactada

• Se efectúa un ensayo de penetración & − ( con pistón ) = 50-- (foto).

• /01 = max 5/.12336.89:; ,

51.4533<=.>9:; ⋅ 100

• Con el valor /01 se diseña una subbase, subrasante.12

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0 1 2 3 4 5 6 7 8 9 10 11 12 13

σ1 (MPa)

δ [mm]

CURVA DE PENETRACIÓN - C1 0.20-1.20m

Prueba CBR campo(California Bearing Ratio)

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• Se hace el ensayo con el suelo ya compactado en obra.

• Se posiciona el pistón de carga, el equipo de reacción y el marco de referencia para medir desplazamiento.

• Se efectúa un ensayo de penetración & − ( con pistón ) = 50-- (foto).

• /01 = max 5/.12336.89:; ,

51.4533<=.>9:; ⋅ 100

• Con el valor /01 se evalúa la calidad de una subbase, subrasante.13

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0 1 2 3 4 5 6 7 8 9 10 11 12 13

σ1 (MPa)

δ [mm]

CURVA DE PENETRACIÓN - C1 0.20-1.20m

Valores CBR recomendados para subrasantes

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Table 4.1 Recommended k-value ranges for various soil types (adapted from Hall et al.1997: 80, AASHTO 1998: 6)

AASHTOClass

Description ASTM/USCSclass

Dry density,kg/m3

(lb/ft3)

CBR(percent)

k-value,MPa/m(psi/in)

Coarse-grained soilsA-1-a, wellgraded

Gravel GW, GP 2,000–2,240(125–140)

60–80 81–122(300–450)

A-1-a,poorlygraded

1,920–2,080(120–130)

35–60 81–108(300–400)

A-1-b Coarse sand SW 1,760–2,080(110–130)

20–40 54–108(200–400)

A-3 Fine sand SP 1,680–1,920(105–120)

15–25 41–81(150–300)

A-2 soils (granular material with high fines)A-2-4,gravelly

Silty gravel GM 2,080–2,320(130–145)

40–80 81–136(300–500)

A-2-5,gravelly

Silty sandy gravel

A-2-4, sandy Silty sand SM 1,920–2,160(120–135)

20–40 81–108(300–400)

A-2-5, sandy Silty gravelly sandA-2-6,gravelly

Clayey gravel GC 1,920–2,240(120–140)

20–40 54–122(200–450)

A-2-7,gravelly

Clayey sandygravel

A-2-6, sandy Clayey sand SC 1,680–2,080(105–130)

10–20 41–95(150–350)

A-2-7, sandy Clayey gravellysand

Fine-grained soils∗

A-4 Silt ML, OL 1,440–1.680(90–105)

4–8 7–45(25–165)∗

Silt/sand/ gravelmixture

1,600–2,000(100–125)

5–15 11–60(40–220)∗

A-5 Poorly graded silt MH 1,280–1,600(80–100)

4–8 7–51(25–190)∗

A-6 Plastic clay CL 1,600–2,000(100–125)

5–15 7–69(25–255)∗

A-7-5 Moderately plasticelastic clay

CL, OL 1,440–2,000(90–125)

4–15 7–58(25–215)∗

A-7-6 Highly plasticelastic clay

CH, OH 1,280–1,760(80–110)

3–5 11–60(40–220)∗

∗ k-value of a fine-grained soil is highly dependent on degree of saturation

Table 4.1 Recommended k-value ranges for various soil types (adapted from Hall et al.1997: 80, AASHTO 1998: 6)

AASHTOClass

Description ASTM/USCSclass

Dry density,kg/m3

(lb/ft3)

CBR(percent)

k-value,MPa/m(psi/in)

Coarse-grained soilsA-1-a, wellgraded

Gravel GW, GP 2,000–2,240(125–140)

60–80 81–122(300–450)

A-1-a,poorlygraded

1,920–2,080(120–130)

35–60 81–108(300–400)

A-1-b Coarse sand SW 1,760–2,080(110–130)

20–40 54–108(200–400)

A-3 Fine sand SP 1,680–1,920(105–120)

15–25 41–81(150–300)

A-2 soils (granular material with high fines)A-2-4,gravelly

Silty gravel GM 2,080–2,320(130–145)

40–80 81–136(300–500)

A-2-5,gravelly

Silty sandy gravel

A-2-4, sandy Silty sand SM 1,920–2,160(120–135)

20–40 81–108(300–400)

A-2-5, sandy Silty gravelly sandA-2-6,gravelly

Clayey gravel GC 1,920–2,240(120–140)

20–40 54–122(200–450)

A-2-7,gravelly

Clayey sandygravel

A-2-6, sandy Clayey sand SC 1,680–2,080(105–130)

10–20 41–95(150–350)

A-2-7, sandy Clayey gravellysand

Fine-grained soils∗

A-4 Silt ML, OL 1,440–1.680(90–105)

4–8 7–45(25–165)∗

Silt/sand/ gravelmixture

1,600–2,000(100–125)

5–15 11–60(40–220)∗

A-5 Poorly graded silt MH 1,280–1,600(80–100)

4–8 7–51(25–190)∗

A-6 Plastic clay CL 1,600–2,000(100–125)

5–15 7–69(25–255)∗

A-7-5 Moderately plasticelastic clay

CL, OL 1,440–2,000(90–125)

4–15 7–58(25–215)∗

A-7-6 Highly plasticelastic clay

CH, OH 1,280–1,760(80–110)

3–5 11–60(40–220)∗

∗ k-value of a fine-grained soil is highly dependent on degree of saturation

Table 4.1 Recommended k-value ranges for various soil types (adapted from Hall et al.1997: 80, AASHTO 1998: 6)

AASHTOClass

Description ASTM/USCSclass

Dry density,kg/m3

(lb/ft3)

CBR(percent)

k-value,MPa/m(psi/in)

Coarse-grained soilsA-1-a, wellgraded

Gravel GW, GP 2,000–2,240(125–140)

60–80 81–122(300–450)

A-1-a,poorlygraded

1,920–2,080(120–130)

35–60 81–108(300–400)

A-1-b Coarse sand SW 1,760–2,080(110–130)

20–40 54–108(200–400)

A-3 Fine sand SP 1,680–1,920(105–120)

15–25 41–81(150–300)

A-2 soils (granular material with high fines)A-2-4,gravelly

Silty gravel GM 2,080–2,320(130–145)

40–80 81–136(300–500)

A-2-5,gravelly

Silty sandy gravel

A-2-4, sandy Silty sand SM 1,920–2,160(120–135)

20–40 81–108(300–400)

A-2-5, sandy Silty gravelly sandA-2-6,gravelly

Clayey gravel GC 1,920–2,240(120–140)

20–40 54–122(200–450)

A-2-7,gravelly

Clayey sandygravel

A-2-6, sandy Clayey sand SC 1,680–2,080(105–130)

10–20 41–95(150–350)

A-2-7, sandy Clayey gravellysand

Fine-grained soils∗

A-4 Silt ML, OL 1,440–1.680(90–105)

4–8 7–45(25–165)∗

Silt/sand/ gravelmixture

1,600–2,000(100–125)

5–15 11–60(40–220)∗

A-5 Poorly graded silt MH 1,280–1,600(80–100)

4–8 7–51(25–190)∗

A-6 Plastic clay CL 1,600–2,000(100–125)

5–15 7–69(25–255)∗

A-7-5 Moderately plasticelastic clay

CL, OL 1,440–2,000(90–125)

4–15 7–58(25–215)∗

A-7-6 Highly plasticelastic clay

CH, OH 1,280–1,760(80–110)

3–5 11–60(40–220)∗

∗ k-value of a fine-grained soil is highly dependent on degree of saturation

Table 4.1 Recommended k-value ranges for various soil types (adapted from Hall et al.1997: 80, AASHTO 1998: 6)

AASHTOClass

Description ASTM/USCSclass

Dry density,kg/m3

(lb/ft3)

CBR(percent)

k-value,MPa/m(psi/in)

Coarse-grained soilsA-1-a, wellgraded

Gravel GW, GP 2,000–2,240(125–140)

60–80 81–122(300–450)

A-1-a,poorlygraded

1,920–2,080(120–130)

35–60 81–108(300–400)

A-1-b Coarse sand SW 1,760–2,080(110–130)

20–40 54–108(200–400)

A-3 Fine sand SP 1,680–1,920(105–120)

15–25 41–81(150–300)

A-2 soils (granular material with high fines)A-2-4,gravelly

Silty gravel GM 2,080–2,320(130–145)

40–80 81–136(300–500)

A-2-5,gravelly

Silty sandy gravel

A-2-4, sandy Silty sand SM 1,920–2,160(120–135)

20–40 81–108(300–400)

A-2-5, sandy Silty gravelly sandA-2-6,gravelly

Clayey gravel GC 1,920–2,240(120–140)

20–40 54–122(200–450)

A-2-7,gravelly

Clayey sandygravel

A-2-6, sandy Clayey sand SC 1,680–2,080(105–130)

10–20 41–95(150–350)

A-2-7, sandy Clayey gravellysand

Fine-grained soils∗

A-4 Silt ML, OL 1,440–1.680(90–105)

4–8 7–45(25–165)∗

Silt/sand/ gravelmixture

1,600–2,000(100–125)

5–15 11–60(40–220)∗

A-5 Poorly graded silt MH 1,280–1,600(80–100)

4–8 7–51(25–190)∗

A-6 Plastic clay CL 1,600–2,000(100–125)

5–15 7–69(25–255)∗

A-7-5 Moderately plasticelastic clay

CL, OL 1,440–2,000(90–125)

4–15 7–58(25–215)∗

A-7-6 Highly plasticelastic clay

CH, OH 1,280–1,760(80–110)

3–5 11–60(40–220)∗

∗ k-value of a fine-grained soil is highly dependent on degree of saturation

k (MPa/m): ensayo de plato de carga

Control densidad in situ: un ejemploLa

b 03

-C

ompa

ctac

ión

de s

uelo

s

15

Tacuarí 1184 - C1071AAX – Buenos Aires Tel: 011 4361-3869 / Fax: 4300-2082 info@aosa.com.ar www.aosa.com.ar

27/03/19 4854 Exolgan - R - Dock Sud - C.docx página 12

Normas de trabajo Se trabajó con normas ASTM, en particular:

D0422-02 Test Method for Particle-Size Analysis of Soils. D1557-02E01 Test Methods for Laboratory Compaction Characteristics of Soil Using Modified Effort. D1883-99 Test Method for CBR (California Bearing Ratio) of Laboratory-Compacted Soils. D1140-00 Test Method for Amount of Material in Soils Finer Than the No. 200 (0.075mm) Sieve. D2216-98 Test Method for Laboratory Determination of Water Content of Soil and Rock by Mass. D2217-98 Practice for Wet Preparation of Soil Samples for Particle-Size Analysis. D4318-00 Test Methods for Liquid Limit, Plastic Limit, and Plasticity Index of Soils.

ANEXO III: REGISTRO FOTOGRÁFICO

Figura 1: Equipamiento de ensayo cono de arena.

Tacuarí 1184 - C1071AAX – Buenos Aires Tel: 011 4361-3869 / Fax: 4300-2082 info@aosa.com.ar www.aosa.com.ar

27/03/19 4854 Exolgan - R - Dock Sud - C.docx página 3

ANEXO I: UBICACIÓN PLANIMÉTRICA DE LOS SITIOS DE CONTROL

Vista general

Sector 1 - COCOIL

Tacuarí 1184 - C1071AAX – Buenos Aires Tel: 011 4361-3869 / Fax: 4300-2082 info@aosa.com.ar www.aosa.com.ar

27/03/19 4854 Exolgan - R - Dock Sud - C.docx página 5

ANEXO II: ENSAYOS EN CAMPO Y EN LABORATORIO

Controles de densidad in situ

Sector 1 - COCOIL

(nota: el peso unitario seco máximo utilizado para calcular el grado de compactación es !" = 21.1'(/*+, obtenido de los ensayos de compactación Proctor modificado ejecutados).

Sector 2 - ARENERA

(nota: el peso unitario seco máximo utilizado para calcular el grado de compactación es !" = 21.5'(/*+, obtenido de los ensayos de compactación Proctor modificado ejecutados).

AOSA SA - Tacuarí 1184 C1071AAX - CABA - Tel: 4361 3869

www.aosa.com.ar - info@aosa.com.ar

Norma: ASTM D1556-00Responsable: A. Escobar Densidad de arena: 15.5 kN/m3 (cono por sobre agujero)Proyecto: 4854 EXOLGAN - COCOIL

(gr) (gr) (gr) (gr) (gr) (gr) (cm3) (%) (kN/m3) (kN/m3)16-Nov 1 - T1 3464,46 4926 494 4432 1904 2528 1631 6,0% 20,8 19,7 93%16-Nov 2 - T1 3154,46 4319 132 4187 1904 2283 1473 6,0% 21,0 19,8 94%16-Nov 2 - T2 3183,46 4210 22 4188 1904 2284 1474 6,8% 21,2 19,8 94%03-Dec 3 - T1 3957,46 5166 280 4886 1904 2982 1924 5,9% 20,2 19,1 90%03-Dec 4 - T1 4845,46 10332 5024 5308 1904 3404 2196 5,9% 21,6 20,4 97%03-Dec 5 - T1 3130,46 5166 778 4388 1904 2484 1603 5,0% 19,2 18,3 87%

PESO ARENA

AGUJERO + CONO

PESO ARENA

EN CONO

PESO UNIT.

HÚMEDO

PESO ARENA

AGUJEROFECHA LUGAR ENSAYO

VOL. ARENA

AGUJEROHUMEDAD GRADO DE

COMPACTACIÓN

COCOIL

PESO UNIT. SECO

CONTROL DENSIDAD IN SITU22/10/2018Fecha :

PESO SUELO

HUMEDO

PESO ARENA INICIAL

PESO ARENA FINAL

!

AOSA SA - Tacuarí 1184 C1071AAX - CABA - Tel: 4361 3869

www.aosa.com.ar - info@aosa.com.ar

Norma: ASTM D1556-00Responsable: A. Escobar Densidad de arena: 15.5 kN/m3 (cono por sobre agujero)Proyecto: 4854 EXOLGAN - ARENERA

(gr) (gr) (gr) (gr) (gr) (gr) (cm3) (%) (kN/m3) (kN/m3)27-Dec 1 - T1 4199 6578 1599 4979 1904 3075 1984 4,7% 20,8 19,8 92%27-Dec 2 - T1 3638 6093 1612 4481 1904 2577 1663 5,5% 21,5 20,3 95%07-Feb 3 - T1 3833 5900 1205 4695 1904 2791 1801 5,4% 20,9 19,8 92%07-Feb 4 - T1 4004 7125 2265 4860 1904 2956 1907 3,9% 20,6 19,8 92%

GRADO DE COMPACTA

CIÓN

PESO UNIT. SECO

CONTROL DENSIDAD IN SITU27/12/2018Fecha :

PESO SUELO

HUMEDO

PESO ARENA INICIAL

PESO ARENA FINAL

ARENERA

PESO ARENA

AGUJERO + CONO

PESO ARENA EN

CONO

PESO UNIT.

HÚMEDO

PESO ARENA

AGUJEROFECHA LUGAR ENSAYO

VOL. ARENA

AGUJEROHUMEDAD

!

Sitio de trabajo

Mediciones en campo y laboratorio (USCS = GW− GM, $!"á$ = 21.1?@/B()

Equipo cono de arena

¿Se hizo bien el

trabajo de campo?

Videos

• Ensayo Proctor– https://www.youtube.com/watch?v=tqHNK67IgG4– https://www.youtube.com/watch?v=gH7AwmA5bXA

• Ensayo CBR– https://www.youtube.com/watch?v=Naxkh_M4Oic

• Control densidad– https://www.youtube.com/watch?v=IlF3m4OLFwc– https://www.youtube.com/watch?v=ojH0W3xq3P0

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ADVERTENCIA: Los videos que aquí se presentan son a fines ilustrativos y tienen por único objetivo que el alumno/a visualice las etapas de cada ensayo. Por consiguiente,

no deben ser interpretados como material de aprendizaje previamente calificado.

Estudio de mezclas: diseño de barrera hidráulica para relleno sanitario

• El LMS-FIUBA viene desarrollando Tesis de grado en estaárea (Martí L. 2015, Casagrande C. 2018, Pileggi A. 2020)

• Objetivo: diseñar una mezcla óptima fino-grueso y adiciónde polímero (APAM) apta para uso en barrera hidráulica.

• Suelo fino: MH (LL=60, IP=20, #200=95%)• Suelo grueso: SP (#200=4%, Cu=2.5, Cc=1.3)• Requisitos fundamentales en barreras: UCS y $

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form the hydrogel. During the mixing, the hydrogel would bondto the mineral surface of CRclay and then increase the bondstrength of adjacent sand aggregates, promoting the formation ofinterparticle bridging for the coarse-textured soil, as explained byYang et al. (2011).

Suction measurement and hydraulic conductivity of themixturesThe hydraulic effect of adding APAM to clay and sandcomposites can be studied with the filter-paper method (ASTM D5298-16). The measurements were performed on several sampleswith different initial water contents for each of the four types ofsoil–polymer composites: CRclay, CRclay–APAM, sand–CRclayand sand–CRclay–APAM. This measurement estimated the totaland matric suctions at equilibrium and gave an insight into theunsaturated permeability of the composites.

The water retention properties of CRclay and CRclay–APAM andthose of sand–CRclay and sand–CRclay–APAM are presented inFigure 12 in a suction–degree of saturation plot. APAM changesthe water retention properties of CRclay and sand–CRclaysystems, particularly the pore organisation and infiltration ofwater. The experimental results were fitted with the vanGenuchten model (van Genuchten, 1980)

Se ¼ 1 þ SSae

! "1= 1−lð Þ" #−l

2.

where Se is the effective degree of saturation; S is the matricsuction; Sae is the air-entry value; and l is a parameter of poresize distribution. The parameters calibrated with the experimentaldata are synthesised in Table 5.

The experimental data and the van Genuchten model for the CRclayand CRclay–APAM composites plotted in Figure 7 show a similarvalue for the parameter l, which is related to the slope of the waterretention curve (WRC). However, the air-entry value (Sae) forCRclay–APAM increases five times the value of the natural CRclay.The air-entry value is related to the stress that must be exceeded forthe air to enter the pores and the soil to begin to desaturate. Thus,water retention is much higher with the addition of APAM, and thedesaturation will be very slow, which means that, once water hasentered the pores, it will be very hard to eliminate it.

In the case of sand–CRclay and sand–CRclay–APAM systemsshown in Figure 12, it can be observed that the parameter l tendsto increase for sand mixtures, in accordance with the change inporosity size. The addition of APAM reduces slightly the slope ofWRC.

The air-entry value of sand–CRclay–APAM was higher than thatof sand–CRclay. Adding APAM generated a more uniform porestructure with less porosity. The CRclay–APAM interaction altersthe surface properties of CRclay (Inyang and Bae, 2005) andinfluences the CRclay and sand–CRclay arrangement. The typeand number of particle association depend on the solid content ofthe system (Sungho and Palomino, 2009); this aspect could be a

CRclayAPAM

Sand

(a)

CRclay−APAM

(b)Sand−CRclay−APAM

(c)

Figure 11. Schematic representation of the interaction between soil and polymer. (a) Initially, the three materials are dissociated.(b) APAM and CRclay absorb water and expand. (c) Expanded APAM and CRclay bridge coarse-textured sand

9

Environmental Geotechnics Polymer-enhanced soil mixtures forpotential use as covers or liners in landfillsystemsPiqué, Manzanal, Codevilla and Orlandi

Offprint provided courtesy of www.icevirtuallibrary.comAuthor copy for personal use, not for distribution

form the hydrogel. During the mixing, the hydrogel would bondto the mineral surface of CRclay and then increase the bondstrength of adjacent sand aggregates, promoting the formation ofinterparticle bridging for the coarse-textured soil, as explained byYang et al. (2011).

Suction measurement and hydraulic conductivity of themixturesThe hydraulic effect of adding APAM to clay and sandcomposites can be studied with the filter-paper method (ASTM D5298-16). The measurements were performed on several sampleswith different initial water contents for each of the four types ofsoil–polymer composites: CRclay, CRclay–APAM, sand–CRclayand sand–CRclay–APAM. This measurement estimated the totaland matric suctions at equilibrium and gave an insight into theunsaturated permeability of the composites.

The water retention properties of CRclay and CRclay–APAM andthose of sand–CRclay and sand–CRclay–APAM are presented inFigure 12 in a suction–degree of saturation plot. APAM changesthe water retention properties of CRclay and sand–CRclaysystems, particularly the pore organisation and infiltration ofwater. The experimental results were fitted with the vanGenuchten model (van Genuchten, 1980)

Se ¼ 1 þ SSae

! "1= 1−lð Þ" #−l

2.

where Se is the effective degree of saturation; S is the matricsuction; Sae is the air-entry value; and l is a parameter of poresize distribution. The parameters calibrated with the experimentaldata are synthesised in Table 5.

The experimental data and the van Genuchten model for the CRclayand CRclay–APAM composites plotted in Figure 7 show a similarvalue for the parameter l, which is related to the slope of the waterretention curve (WRC). However, the air-entry value (Sae) forCRclay–APAM increases five times the value of the natural CRclay.The air-entry value is related to the stress that must be exceeded forthe air to enter the pores and the soil to begin to desaturate. Thus,water retention is much higher with the addition of APAM, and thedesaturation will be very slow, which means that, once water hasentered the pores, it will be very hard to eliminate it.

In the case of sand–CRclay and sand–CRclay–APAM systemsshown in Figure 12, it can be observed that the parameter l tendsto increase for sand mixtures, in accordance with the change inporosity size. The addition of APAM reduces slightly the slope ofWRC.

The air-entry value of sand–CRclay–APAM was higher than thatof sand–CRclay. Adding APAM generated a more uniform porestructure with less porosity. The CRclay–APAM interaction altersthe surface properties of CRclay (Inyang and Bae, 2005) andinfluences the CRclay and sand–CRclay arrangement. The typeand number of particle association depend on the solid content ofthe system (Sungho and Palomino, 2009); this aspect could be a

CRclayAPAM

Sand

(a)

CRclay−APAM

(b)Sand−CRclay−APAM

(c)

Figure 11. Schematic representation of the interaction between soil and polymer. (a) Initially, the three materials are dissociated.(b) APAM and CRclay absorb water and expand. (c) Expanded APAM and CRclay bridge coarse-textured sand

9

Environmental Geotechnics Polymer-enhanced soil mixtures forpotential use as covers or liners in landfillsystemsPiqué, Manzanal, Codevilla and Orlandi

Offprint provided courtesy of www.icevirtuallibrary.comAuthor copy for personal use, not for distribution

Estadios de interacción arena-arcilla-polímero (Piqué et al, 2019) Polímero APAM

Estudio de mezclas: ¿qué es un relleno sanitario?

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Unad, 2013

Barrera final

Barrera de fondo

Estudio de mezclas: maximización de peso unitario seco

• Mezcla óptima 85%arena (S) + 15% [arcilla (C) + APAM]

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15,2

15,6

16,0

16,4

16,8

17,2

17,6

0% 2% 4% 6% 8% 10% 12% 14% 16% 18% 20% 22% 24% 26%

g d[k

N/m

3 ]

w [%]

100% arena95% arena - 5% arcilla+APAM 1.5%90% arena - 10% arcilla+APAM 1.5%85% arena - 15% arcilla+APAM 1.5%80% arena - 20% arcilla+APAM 1.5%60% arena - 40% arcilla+APAM 1.5%

(LMS FIUBA – 2015)

$!"á$ = 17.3 ?@B(%ó&' = 13%

Estudio de mezclas: variación de resistencia a compresión simple

• Incidencia de la humedad en UCS

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0

2

4

6

8

10

12

14

16

18

0,0% 0,5% 1,0% 1,5% 2,0% 2,5% 3,0% 3,5% 4,0% 4,5% 5,0% 5,5% 6,0% 6,5%

q (kPa)

ε (-)

Mezcla I RHMezcla I RSMezcla I RO

Rama húmeda - RH

Rama seca - RS

Rama óptima - RO

Estudio de mezclas: variación de resistencia a compresión simple

• Incidencia de la humedad y %APAM en UCS

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0

5

10

15

20

25

30

0,0% 0,5% 1,0% 1,5% 2,0% 2,5% 3,0% 3,5% 4,0%

UCS

[kPa

]

APAM [%]

rama seca (RS)rama óptima (RO)rama húmeda (RH)Linear (rama seca (RS))Linear (rama óptima (RO))Expon. (rama húmeda (RH))

(LMS - Casagrande C. 2018)

Bibliografía

• Normas ASTM – American Society of Testing Materials

– D 698 (Proctor estándar)

– D 1557 (Proctor modificado)

– D 1883 (ensayo CBR en laboratorio)

– D 4429 (ensayo CBR en campo)

• Jean-Pierre Bardet – Experimental Soil Mechanics

• Germaine – Geotechnical Laboratory Measurements for Engineers

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