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Home My WebLink AboutCARHART S-3544 · e T[STING · [XPLO"ATIO~ · CH[MICAL · MAT["IAL$ · INSP[CTION Ig40 POST ROAD * ~ 279'258tX W0= $16915 .t~ ~ /l~ .CF Subject= SLtelD~rmoun iff Rocky Road Soil Gentlemen= ,. In response to your recent request, transmitted herein is the log of the test hole placed as specified on 21 August 1974. The test hole was drilled with solid flight auger by a Mobile B-50 drill mounted on a Nodwell tracked vehicle provided by Denall Drilling, Inc. The test hole was logged and sampled by Mr. Kenworthy of our staff. The samples are cuttings removed from the auger bit upon complete withdrawal of the auger from the hole. The general topography in the area of the test hole is such that the test hole is about 7'-8' below the highest point with about a 20'-30' drop in elevation to north and to the east of the test hole. The test hole was drilled in a cleared path through a wooded area with scattered moss and Hudson's Bay Tea being the ground cover. 20-35' birch with dense undergrowth of younger spruce and a few scattered alders are common in the area. The test hole is 100' north of the road and 50' south of property line along the cleared path. The data indicates the soils to be relatively imperme- able down to about 5-1/2'; below that depth, to the depth of exploration 15-1/2', the soils are slightly permeable. They tend to be very dry and may be expected to accept moisture into the void system.by capillarity and to have some aspira- 'tion to the surface through the root system of the foliage. MEMBER Alaska Land Development August 29, 1974 Page 2 The soils are generally highly frost susceptible with the surface material and the layer from 4' to 5-1/2' being the most active in this regard. We recommend that standard subarctic design and construction techniques be followed and that care be given to surface drainage and to the use of perimeter footing drains and frost breaks for structures · founded on these soils. ~~...W.ith respect to.disposal of'on-s~te effluent th'e.G.AAB published relatlonshlp between the unlfled so~l classifica- tion and the number of square feet of absorption area per bedroom indicates this material which is a G~below 5-1/2'/ to require approximately 225 square feet per bedroom. We expect from the action of the drill that layers of cleaner material exist, interspersed within the GM. Therefore, the probability is that an effluent field founded in these materials will be more satisfactory than indicated by the disturbed samples. The use of a narrow leaching pit to increase the wall area for a similar volume may be advan- We trust the foregoing is sufficient to your immediate needs though not necessarily exhaustive of the possibilities. The single test hole may or may not represent the entire area however, it is sufficiently encouraging that we do not recommend additional test holes for either structural or effluent adequacy at this time. Very truly yours, ItRL: rb Enclosure Test Hole A Elevation: Depth in Feet From To TABLE A W.O. 16915 Soil Description 0.0' 0.5' 0.5' 4.0' 4~0' 5.5' 5.5' 15.5' F-4, Tan sandy silt with ash, dry M1 F-l, Tan sandy silty ~ravel, damp, hard 2"-~ GM F-4, Tan sandy gravelly silt, dry to damp, hard, M1 F-l, Tan silty sandy Travel with occasional cobbles, damp, dense, 3"~, G~! Bottom of Test Hole: Frost Line: None Free Water Level: 15.5' None observed T~P~ OF Sample Depth '~A~PI~ 1 5' Grab 2 15' ' Grab ALASKA TESTLAB CONSULTATION · TESTING · EXPLORATION · CHEMICAL · MATERIALS · INSPECTION ~0%GRAVEL CLAY EY CLAYEY CLAYEY~ \ OR : :': LTY HLTY SI LTY -i ~\ '~ \ SAND , ,, \ ~ RAV[E: 2SAND rAVEL GRAVELLY SAND SAN ,Y \(il AVE[;. GRAVEL .' ~:, \ , '~ · .~. \ 0 I0 20 :50 440 50 60 70 80 90 I00 ,GRAVEL (+~IIDSCREEN) % BY · WEIGHT NONFROST SUSCEPTIBLE SOILS ARE INORGANIC SOILS CONTAINING LESS THAN 30/0 FINER THAN O.02mm. GROUPS OF FROST-SUSCEPTIBLE SOILS= FI GRAVELLY SOILS CONTAINING BETWEEN :~ AND 20% FINER THAN O.02mm. F2 ' SANDY SOILS CONTAINING BETWEEN :~ AND 15°/o FINER THAN O.02mm. F:~ a. GRAVELLY SOILS CONTAINING MORE THAN 20°/0 FINER THAN O.02mm. AND SANDY SOILS (EXCEPT FINE SILTY, SANDS) CONTAINING MORE THAN 15°/o FINER THAN O.02mm. b. .CLAYS WITH PLASTICITY INDEXES OF MORE THAN 12. EXCEPT VARVED CLAYS. F4 e. ALL SILTS INCLUDING SANDY SILTS. b. FINI[ SILTY SANDS CONTAINING MORE THAN 15% FINER THAN O.02mm. c. LEAN CLAYS WITH PLASTICITY INDEXES OF LESS THAN 12. d. VARVED CLAYS. SHEET OF TEST HOLE LOGS SOILS DESCRIPTIONS The soil descriptions shown on the logs are the best estimate of the soil charac- teristics at the time of field examination. Such examinations do not achieve the precision of laboratory tests for the various properties. 1. The relative type of soil and the frost classification is shown on the sheet "Soil Classification Chart. ". 2. Other criteria: ' Boulder - greater than 8" Cobble - approximately 3" to 8" Blow Count - blows/6" of 140 lb. weight falling 30"; 2" split spoon. (The standard penetration is blows/12" .) DensSty - estimated by the rate of drilling, type of soil, blow count and ' moisture range PL - Plastic Limit, moisture content being approximated as; above (+) or below (-) plastic limit (PL) or liquid limit (Lw) as appropriate Lw - Liquid Limit, see PL Dllatency - is the ability of water to migrate to the surface upon vibration or Jolting of a sample, an aid in determining whether a soil Is pre- dominately a clay or slit Well graded - uniformity coefficient greater than 7 Poorly. graded - uniformity coefficient less than 7 (Uniform particles, gap graded) Organic Content - estimated by volume, not particularly precise Clayey Soils - a field method now being used as an aid to Identification of these soils as a combination ball drop, and rolled threa'd test in which a 2" diameter ball of the Sand-Sllt-.Clay fraction is dropped 2' untila 1" thick pat develops. The dlameterofa thread at crumbling rolled from the resultant pat determines whether clay or slit predominates. Dry Strength - a small sample of the soil is formed into a cube and air dried, and crushed between the fingers. High dry strength lndt-' cates clays and low indicates silts. Water Table - the apparent water table at the time of observation. Often the actual water table may be higher unless the hole is allowed to remain open or is converted to an bbservatton well. Capillary Fringe - change from moist to very damp, or saturated soil, usually indicates that water table is close. Peat - Flbrgus material of macroscopic and microscopic fragments of cayed vegetable matter; very compressible, unsdltable.for founda- tion or embankment. Co]or light br6wn to black. .Au - The upper layer, surface soil or topsoil, containing humus .and/or organic debris, not satisfactory for foundation. ALASKA TESTLA8 lim~ D