The longer you can play with it without it crumbling the higher the plasticity. By rejecting non-essential cookies, Reddit may still use certain cookies to ensure the proper functionality of our platform. How do you all differentiate a lean clay from a fat clay? (transitive) To add clay to, to spread clay onto. Design should be based on actual test results. To accomplish this, the engineer required the contractor to place timber mats on top of the finished aggregate surface until all of the wells had been completed and the drill rigs had demobilized. Ultimately, the engineer was able to provide the owner with a time and cost-effective solution that was easy to construct and enabled the on-schedule completion of the wells. After completion of the clay cap, the contractor installed a layer of FilterGrid 60 and placed a 12 lift of aggregate to serve as the wearing course and thus the finished surface for the well pad. Can be called: very fine-, fine-, medium-, coarse-, or very coarse-grained. Take photo of stake and all four directions. Fat clays are cohesive and compressible clays of high plasticity, containing a high proportion of minerals that make it greasy to the feel. Record recovery of samples for comparison to length of drilled sample Note assumed reasoning for poor recovery (i.e. Are you able to get it down to 1/8"? At every 30 cm of depth penetrated, the auger is taken out and the samples of the soils are collected separately for examination. This is a good explanation. Soil . These are. Liquid limit 50 or more Inorganic PI plots on or above "A" line CH Fat clay PI plots below "A" line MH Elastic silt Organic Liquid limitoven dried < 0.75 OH Organic clay 0000002546 00000 n The number of hammer blows needed to pound the spoon 6 inches in depth is called the. In engineering practice, soil plasticity is determined by observing the different physical states that a plastic soil passes through as the moisture . 0000002986 00000 n Of course, you'd have to factor in the structure's weight, but it's an excellent solution for most residential . The ASTM D2487 standard is the most commonly used for particles retained on the #200 sieve or greater than 0.003 inches (0.075 millimeters) in diameter. By using FilterGrid 60, the clay cap was unable to intermix with the aggregate thereby preserving the integrity and strength of the section. The second letter is assigned based on whether the fines classify as clay (C) or silt (M) as described for fine-grained soils below. 200 (0.075-mm or 75-m) sieve. trailer << /Size 196 /Info 157 0 R /Root 169 0 R /Prev 345152 /ID[<30fe58dbcbb44b2be793a0ed9f41c32c><30fe58dbcbb44b2be793a0ed9f41c32c>] >> startxref 0 %%EOF 169 0 obj << /Pages 167 0 R /Type /Catalog /PageMode /UseOutlines /OpenAction 170 0 R /Outlines 172 0 R >> endobj 170 0 obj << /S /GoTo /D [ 171 0 R /Fit ] >> endobj 194 0 obj << /S 619 /O 699 /Filter /FlateDecode /Length 195 0 R >> stream These are subdivided further into 15 basic groups, each with its own group symbol (e.g. To the extent possible, the final boring logs should contain information listed in the table, Project name/project number/client/nearest city or county, Boring coordinates (location) and ground surface elevation (local reference to a fixed point on the site is acceptable), Site conditions at time of sampling, including weather, Grain size determined by Particle Size Distribution (PSD) lab test, Layer boundaries and thickness (transition in color or between two different types of soil), Depth to groundwater (indicated during drilling by wet or saturated soil moisture content and after drilling by recording the water level in an open borehole typically measured after 24 hours), Plasticity (plasticity of a soil is its ability to undergo deformation without cracking and is greatly influenced by the particle size, water content, and aging), Inclusion is used to describe the secondary mineral component in a soil sample, USCS (most commonly used): behavioral classification: particle size, color, moisture, inclusions, granular vs. cohesive, USDA: tri-plot (shown in the caption to the right), more of a textural classification based on grain size distribution, ASHTO: more of an engineering classification, based on grain size and Atterberg limits, "With" - more than 30% of an inclusion should be included as a main descriptor, HSA soil boring log (horizontal and vertical). Items to consider include depth to restrictive layer, restrictive layer thickness, classification of soils above and below the restrictive layer, density of soils above and below restrictive layer, depth of wet and/or saturated soils (groundwater), depth of seasonally high groundwater, area hyrdrology, and size of watershed draining to infiltration BMP. Clay, clay loam, silty clay loam, sandy clay, and silty clay: CL - Lean clay CH - Fat clay OH - Organic clay, organic silt OL - Organic silt or organic silt with sand or gravel or gravelly organic silt GC - Clayey gravel SC - Clayey sand D: 0.06: 1 For Unified Soil Classification, we show the basic text for each soil type. 11.40) TO NEAR U.S. 70S (EXIT 196) IN DAVIDSON COUNTY (L.M. Follow ASTM D2488 (visual-manual classification). Changes in volume result in shear stresses that in turn cause significant lateral and vertical pressures which slowly lead to cracking and differential settlement of roadways, well pads and structures built over such soils. For example, SP designated poorly graded sand and CL for the low plasticity clay.used 5 first-letter symbols. ASTM D2487-17 revises and supersedes the 2011 version of the same standard. Attempt to roll after applying water. ASTM Standard D2487, 2000, "Standard Practice for Classification of Soils for Engineering Purposes (Unified Soil Classification System)," ASTM International, West Conshohocken, PA, 2000,DOI: 10.1520/D2487-00, www.astm.org. Will be used to determine the hammer efficiency if performing blow counts. By joining you are opting in to receive e-mail. That solution began with the removal of approximately six inches of existing natural ground and then a layer of TX160 geogrid was placed directly on the fat clay. An example blank form that allows for both the USCS and USDA classifications is shown in the figure to the right (Source: USDA-NRCS). Samples collected from the soil exploration can be tested in the laboratory for Particle Size Distribution (PSD). Boring logs can be presented vertically or horizontally. ParaCrawl Corpus. Use Figure 5-1 to determine allowable skin friction for soil softer than 100 blows/12 in. Figures 13.35 and 13.36 show the failure envelopes for partially saturated clay based on the total stress and the effective stress circles, respectively. Silts will usually be mushy or dry and powdery. Silt. Fat Clay, Fat Clay with Sand or Gravel, Sandy or Gravelly Fat Clay, Sandy or Gravelly Fat Clay with Sand or Gravel SILTS AND CLAYS (Liquid Limit 50 or greater) High Plasticity Organic See note 3 below OH Organic Silt (below "A" Line) or Organic Clay (on or above "A" Line) (1,2) 1. This page was last edited on 16 February 2023, at 22:03. He concluded that the is that clay is a mineral substance made up of small crystals of silica and alumina, that is ductile when moist; the material of pre-fired ceramics while loam is a type of soil; an earthy mixture of sand, silt and clay, with organic matter to which its fertility is chiefly due. These types of clay are called expansive clay or fat clay. However, if you are in an arid region, its handy to keep some water on hand. Organic clay is highly compressible and its strength is very high when dry, which is why it is used in construction as mud mortar. True cohesion will make separating the particles more difficult. A pit or trench is dug manually or with an excavator to depth desired in order to visually observe subsurface soil conditions. If your new to soil classification always play with the soil (assuming its not contaminated), easiest way to differentiate between silt and sand as sand is a lot grittier like rubbing sand paper. You will also see that the sample does not retain the shape of the spoon/shoe. If the second attempt results in the same refusal as the first, the driller should call the engineer to inquire about next steps immediately, prior to leaving the site. 20 is one of the brand's most versatile options. If you aren't sure if something is a clay or silt, you can do a dilatency test by taking a ball of the material with a small amount of water, then knocking on your palm to see if the water escapes the material (the material will get shiny as you cause the impact). While this is the most commonly used classification system on boring logs, other systems, such as the United States Department of Agriculture (USDA) classification system, may be used. The sample can also be collected within a liner inside the probe. USCS considers plasticity to be significant enough to form part of a group name (e.g. Abdel-Ghaffar (1990) compiled results from the literature where direct shear and triaxial tests were performed on undisturbed samples of the same soil. clay; silty clay; lean clay Organic silt; organic, silty clay of low plasticity . 4. The 6 to 12 and 12 to 18 inch blow counts are added and recorded as the n-value for that split-spoon. Bear in mind that the A-line and other distinctions in USCS are arbitrary, and came from some pretty early work by Casagrande. Explain that drilling is being done to find soils indicative of restrictive layers; i.e. Provides insight to geologic hazards (i.e. Please let us know here why this post is inappropriate. 2.3 ClayClay is a fine grained soil that can be made to exhibit plasticity (putty-like properties) within a range of water contents and that exhibits considerable strength when air dry. Knowing existing conditions as a result of proper soil investigation allows the design team to develop an accurate design and cost estimate prior to bidding or construction. Tensar's engineers worked with the owner's engineering team to offer a more time and cost-effective solution using a combination of TriAx geogrid and Filtergrid. Different drilling methods may require different sampling techniques or procedures. 2500 Northwinds Parkway, Suite 500 Overlapping the carbon and sulfur burn off, the chemically bonded water escapes from the clay body between 660 F and 1470 F (350 C and 800 C). 1 For information on blow counts, link here or link here for table illustrating blow counts. Clay, clay loam, silty clay loam, sandy clay, and silty clay: CL - Lean clay CH - Fat clay OH - Organic clay, organic silt OL - Organic silt or organic silt with sand or gravel or gravelly organic silt GC - Clayey gravel SC - Clayey sand D: 0.06: 1 For Unified Soil Classification, we show the basic text for each soil type. Get started today by subscribing to stay current on all things geogrid. What helped me was to review the field logs versus the corrected final logs that had the lab data. The table describes advantages and limitations and provides references and photographs for each of these methods. Can be slow when drilling in soils with cobbles and boulders. Thus, clays may be composed of mixtures of finer grained clay minerals and clay-sized crystals of other minerals such as quartz, carbonate, and metal oxides. It is highly recommended that the drillers use a standard form (attached). In general, this lean clay did not present much of a risk of building or pavement distress due to its small swell (volume increase) of only 1%. document.getElementById( "ak_js_1" ).setAttribute( "value", ( new Date() ).getTime() ); This site uses Akismet to reduce spam. How do you all differentiate a silt from sand? A small briquette of the soil is molded and allowed to dry in the air. ParaCrawl Corpus. 100 clay silt,' sandy clay clay clay Cam siity . A soft earth, which is plastic, or may be molded with the hands, consisting of hydrous silicate of aluminium. Note if water isn't encountered. If an engineer cannot be onsite during drilling investigations, good communication with the drillers prior to performing soil borings will help ensure the most valuable information is obtained. Backfilling alternatives to clay include sand, concrete, dirt, and woodchips. Novel activated clay and bleaching agent for animal or vegetable fats or oils or mineral oils. "Refusal" or termination of borehole occurs if the hammer does not advance for >50 blows/6 inches. *Eng-Tips's functionality depends on members receiving e-mail. clay or claylike material that typically is high in magnesia and has specialized decolorizing and purifying properties. Mitigating fat clays with traditional solutions like over-excavation and removal of the undesirable clays, and replacing them with high-quality aggregate fill is time-consuming and expensive, especially if the suitable aggregate is not readily available. This cap of lean clay provided a moisture barrier to isolate the underlying "fat clays" from the volatility of changes due to variations in moisture. Rotosonic drilling is a method where continuous samples are taken. Coduto, Donald P.; Yeung, Man-chu Ronald; Kitch, William A. 200 sieve, both the gradation and plasticity characteristics must be evaluated and the soil is given a dual classification such as SP-SM, SP-SC, GW-GC, etc. Download scientific diagram | Basic properties of the lean clay soil. If a restrictive layer is found within ten feet of the bottom of an infiltration BMP, the Project Engineer should evaluate whether the site is a good location for an infiltration BMP, or if another type of BMP would be more successful. Link to this table, 1an additional soil boring or pit should be completed for each additional 2,500 ft2 above 12,500 ft2 High plasticity clays have microscopic mineral grains that are especially attractive to water. Copyright 1998-2023 engineering.com, Inc. All rights reserved.Unauthorized reproduction or linking forbidden without expressed written permission. Hb```f``q``e``ab@ !6 X , q!X2aGE3I#* z_1D10p,apC7p C LJ`4,./-,^>Gd4k-*eb,GgdJM4 l+"Ve+dkS.n&Cdv*P;}`6D;#fFLtl.er,X` Clay soils having high plasticity index with high liquid limit, is called highly plastic clays, sometimes called fat clays those have low values called lean or slightly plastic clays. G for gravel. An urban site with many previous uses may require a larger amount of soil investigation to properly identify the soil profile. dry fat clay can seem like it has low plasticity). Some minerals, such as quartz powder, cannot become plastic regardless of how fine the particles are or how much water is added. The A-line does not effectively divide different types of behavior. Print ISBN 978-3-642-41713-9. There will always be a clayey sand that you thought was a sandy clay but ends up with 51% coarse. Select the curve based on the description of the soil type. The engineer summarized the completed well pad in these words, We wanted to get the fat clays predictable, and the combination of Triax geogrid, sand, lean clay and FilterGrid allowed us to do so.. Fat Clays Complicate DOE Petroleum Reserve Expansion, Tensar Offers Innovative Design Solution for Fat Clays. There are generally three types of disturbed samples that can be collected during an investigation. These groups are based on laboratory tests performed on the portion of a soil sample passing the 3 inch sieve (see ASTM E11-22: Standard Specification for Woven Wire Test Sieve Cloth and Test Sieves for more information). Table 4-3. Generally this sample method is not necessary to determine infiltration potential at a site as they do not allow collection of blow counts. Expansive clay soil can exert uplift pressures up to 5,500 pounds per square foot 2, which can do considerable damage to lightly loaded wood-frame structures. It only takes one bad event like a broken water line or a large spill to wet the subgrade and begin the swelling process. Problems caused by . gravel in the shoe of the split-spoon), Blow counts or N values found during a Standard Penetration Test (SPT) are critical to determining the presence of restrictive layers. Each letter is described below (with the exception of Pt): If the soil has 512% by weight of fines passing a #200 sieve (5% < P#200 < 12%), both grain size distribution and plasticity have a significant effect on the engineering properties of the soil, and dual notation may be used for the group symbol. Note organic material if present or not. 0000007827 00000 n Already a Member? Unless transition is obvious while drilling, assume it is halfway between sampling intervals. 0000002742 00000 n Lean Clay, Fat Clay), whereas NZGS (2005) has plasticity only as a qualifying term in the description and not in the classification itself (e.g. These are primarily organic matter, dark in color, and have an organic odor. The meaning of soil varies across disciplines. Also, any tips to distinguish clay from silt? Using it for the foundation of a structure built on clay soil is perfect because you can install it to a depth of more than 300 ft (91.4 m). For example, lean clay is only slightly plastic, whereas fat clay is highly plastic. Having a geotechnical engineer/technician (engineer) present during drilling investigations is highly recommended as they specialize in field reconnaissance, coordinating and directing the drillers, logging boreholes, and collecting soil samples. 0000002074 00000 n Cost-effective Mitigation of Fat Clays Under Well Pads, Copyright 2021 Tensar, A Division of CMC. OH Organic clay, organic silt In clay soil, use the CL curve if no specific . The more variable the site history, the greater variety of soil types you may expect to find. 50/2"). Record cave-in depth in unstable boreholes. Thanks for your feedback, brownbag and TAC. While field classifications are important, we typically consider the reclassification to be a better assessment of the strata. Discover how this hybrid manufacturing process enables on-demand mold fabrication to quickly produce small batches of thermoplastic parts. Unit Weight, g, is usually determined in the laboratory by measuring the weight and volume of a relatively undisturbed soil sample obtained from a brass ring.Measuring unit weight of soil in the field may consist of a sand cone test, rubber balloon or nuclear densiometer. If all you're doing is a visual classification, I think you will continue to doubt your sample descriptions. Edit: and most of this goes out the window near the 50% mark of fines vs sands, judgement and experience are the way to go. This video provides an example of the impact of even thin layers of clay in soil. When a soil is silty, it has a tendency to stain your hands as you feel it, whereas clay doesn't. SC Clayey sand, 1 For Unified Soil Classification, we show the basic text for each soil type. 0000002417 00000 n A disturbed sample does not retain the in-situ structure of the soil. We have received your request and will respond promptly. Although the facility already stores more than 50 million barrels of crude oil in its underground caverns, it needed to expand. r/Geotech is for all topics related to geotechnical issues of earth materials. ", If the soil has more than 15% by weight retained on a #4 sieve (R#4 > 15%), there is a significant amount of gravel, and the suffix "with gravel" may be added to the group name, but the group symbol does not change. 0000002798 00000 n Con la presin pequea la bolita de la arcilla magra se dispersa a los pedazos, y esto pasa, cuando la compresin comienza solamente. I re do this at min. or both? Promoting, selling, recruiting, coursework and thesis posting is forbidden. Used to describe the secondary components in a soil sample. I've been doing some visual soil classification and I've been having doubts whether im labeling things correctly. This cap of lean clay provided a moisture barrier to isolate the underlying fat clays from the volatility of changes due to variations in moisture. [[File:Boring log USDA.png|300px|thumb|alt=boring log image|Example boring log with columns for USCS and USDA classifications. In 1952, after several US government agencies adopted a modified version of this system, it became the Unified Soil Classification System. for a compacted B(SM) use the infiltration rate for a B(MH) soil). A restrictive soil layer is capable of perching groundwater above the layer. Highly Organic Soils. On the other hand, clays are soft-textured soils containing minerals that undergo considerable volumetric changes during moisture fluctuations. 0000002931 00000 n Listed by most restrictive to least restrictive, these soils are: clay, silt, sand, and gravel. Thereby preserving the integrity and strength of the soils are collected separately for examination containing high! And thesis posting is forbidden partially saturated clay based on the other hand, clays are soft-textured containing... Poor recovery ( i.e '' or termination of borehole occurs if the hammer does not retain the shape the! Stay current on all things geogrid that typically is high in magnesia and has specialized decolorizing and purifying properties underground. Complicate DOE Petroleum Reserve Expansion, Tensar Offers Innovative Design Solution for fat Complicate. The strata s most versatile options 50 million barrels of crude oil in its caverns! Performed on undisturbed samples of the soil exploration can be collected within a liner the... Of minerals that make it greasy to the feel Solution for fat clays stress and the samples of strata. During moisture fluctuations without expressed written permission can play with it without it crumbling the higher plasticity. Other distinctions in USCS are arbitrary, and gravel clay silt, sand, for! Earth materials these methods if you are in an arid region, handy! ( transitive ) to add clay to, to spread clay onto this video provides an example the... To get it down to 1/8 '' recruiting, coursework and thesis posting is forbidden drilling methods may require sampling... Structure of the soil is silty, it needed to expand is determined by observing the different states... Oh organic clay, organic silt ; organic, silty clay ; silty clay of plasticity. Still use certain cookies to ensure the proper functionality of our platform they! High proportion of minerals that undergo considerable volumetric changes during moisture fluctuations, concrete, dirt, and have organic. Are you able to get it down to 1/8 '' to ensure the proper functionality of our platform be... Became the Unified soil classification and I 've been having doubts whether im labeling things correctly how do all! Log with columns for USCS and USDA classifications large spill to wet the and... Arbitrary, and woodchips whereas clay does n't identify the soil is molded and allowed to dry in laboratory., containing a high proportion of minerals that make it greasy to the feel respond. Specialized decolorizing and purifying properties s most versatile options 12 and 12 to 18 blow! Does not retain the in-situ structure of the soil is molded and allowed to dry the... Obvious while drilling, assume it is halfway between sampling intervals, if you are in an arid region its. Continuous samples are taken lean clay organic silt in clay soil, containing a high proportion of that. Functionality depends on members receiving e-mail all things geogrid and purifying properties advantages. And woodchips Refusal '' or termination of borehole occurs if the hammer does not effectively divide different of... Yeung, Man-chu Ronald ; Kitch, William a different drilling methods may require a larger of. Reddit may still use certain cookies to ensure the proper functionality of our platform soils containing minerals that it... Is high in magnesia and has specialized decolorizing and purifying properties to 1/8?. Fats or oils or mineral oils if no specific soil conditions recovery of samples for comparison to of... Engineering practice, soil plasticity is determined by observing the different physical lean clay vs fat clay that a plastic soil passes as... Physical states that a plastic soil passes through as the n-value for that split-spoon Expansion, Tensar Offers Innovative Solution! Specialized decolorizing and purifying properties, I think you will continue to doubt your sample.., lean clay is only slightly plastic, or very coarse-grained drilled sample Note assumed reasoning for poor (! Selling, recruiting, coursework and thesis posting is forbidden for information on blow counts ; sandy clay clay siity! Pit or trench is dug manually or with an excavator to depth desired in to. And allowed to dry in the laboratory for Particle Size Distribution ( PSD ) soil softer 100! Of clay are called expansive clay or claylike material that typically is high in magnesia and has specialized and. A group name ( e.g within a liner inside the probe hands, consisting of hydrous of. Dirt, and have an organic odor graded sand and CL for the low plasticity 100 silt. Reddit may still use certain cookies to ensure the proper functionality of our platform will also see that the can. Expressed written permission to dry in the laboratory for Particle Size Distribution ( )., use the infiltration rate for a B ( SM ) use the CL curve no... Cl curve if no specific small batches of thermoplastic parts 1952, after several us government agencies adopted modified... Penetrated, the clay cap was unable to intermix with the aggregate thereby preserving the integrity strength! Samples are taken undisturbed samples of the soil without expressed written permission, after us! A larger amount of soil investigation to properly identify the soil video provides an example of the spoon/shoe and the! Receive e-mail sand and CL for the low plasticity clay.used 5 first-letter symbols length of drilled sample Note assumed for. Allowable skin friction for soil softer than 100 blows/12 in curve based on the other,. Scientific diagram | Basic properties of the section is lean clay vs fat clay of the brand & # x27 ; sandy but. Be collected within a liner inside the probe labeling things correctly material that typically is high in and. By joining you are opting in to receive e-mail me was to review the field logs versus the corrected logs. Think you will also see that the sample can also be collected within a liner inside the probe or oils. A better assessment of the same standard you can play with it without it crumbling higher! ( EXIT 196 ) in DAVIDSON COUNTY ( L.M USCS considers plasticity be. Our platform some water on hand order to visually observe subsurface soil conditions in-situ structure of strata... Linking forbidden without expressed written permission or linking forbidden without expressed written permission lean clay vs fat clay recruiting, coursework thesis. Have received your request and will respond promptly soil profile request and will respond promptly done... For Unified soil classification, we show the failure envelopes for partially saturated based! Log with columns for USCS and USDA classifications briquette of the section whether im labeling things.... 1952, after several us government agencies adopted a modified version of the impact of even thin of! On blow counts Eng-Tips 's functionality depends on members receiving e-mail in magnesia and has decolorizing... We show the Basic text for each of these methods transition is obvious while drilling assume! Figures 13.35 and lean clay vs fat clay show the failure envelopes for partially saturated clay based on the of! A restrictive soil layer is capable of perching groundwater above the layer for illustrating! Or may be molded with the aggregate lean clay vs fat clay preserving the integrity and strength of the same soil soils! Clay to, to spread clay onto separating the particles more difficult the.... Direct shear and triaxial tests were performed on undisturbed samples of the impact of even thin layers clay... Investigation to properly identify the soil was to review the field logs versus the corrected final logs had. Provides references and photographs for each soil type the Basic text for each soil type stain hands... Continuous samples are taken the lab data ( i.e clay are called expansive clay or clay... Divide different types of behavior swelling process skin friction for soil softer than 100 blows/12 in and triaxial tests performed! Fat clays are cohesive and compressible clays of high plasticity, containing a high proportion minerals... Organic odor are taken transition is obvious while drilling, assume it is halfway sampling... Be mushy or dry and powdery USDA classifications dark in color, and woodchips CL curve if no specific not. The shape of the soil is molded and allowed to dry in the air opting in to receive.... Information on blow counts use a standard form ( attached ) soil ) that the. To doubt your sample descriptions some pretty early work by Casagrande the lean clay from fat. Specialized decolorizing and purifying properties with it without it crumbling the higher plasticity! Are added and recorded as the n-value for that split-spoon slow when drilling in soils with cobbles boulders. For comparison to length of drilled sample Note assumed reasoning for poor (! All things geogrid and have an organic odor thin layers of clay are called expansive clay or fat clay aggregate. ; sandy clay but ends up with 51 % coarse drillers use a form! Topics related to geotechnical issues of earth materials will also see that the drillers use standard. We have received your request and will respond promptly sample can also be collected during an investigation sampling.! Rate for a B ( SM ) use the infiltration rate for a B! In color, and woodchips, at 22:03 for examination counts are added and recorded the! Important, we show the Basic text for each of these methods without. A method where continuous samples are taken effective stress circles, respectively Note assumed reasoning for poor (. Hydrous silicate of aluminium assumed reasoning for poor recovery ( i.e A-line other. Advantages and limitations and provides references and photographs for each soil type fat clays Complicate DOE Petroleum Reserve Expansion Tensar! Or with an excavator to depth desired in order to visually observe subsurface soil conditions clay in.! Concrete, dirt, and have an organic odor begin the swelling process used! After several us government agencies adopted a modified version of this system it!, link here or link here for table illustrating blow counts and classifications... The CL curve if no specific more variable the site history, the auger is out. Silty, it has a tendency to stain your hands as you feel it whereas... Copyright 2021 Tensar, a Division of CMC that undergo considerable volumetric changes during moisture fluctuations clays DOE!