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HomeMy WebLinkAboutJOHNNA'S WOODS Lots 1-3 Plat# 78-140 & 70-308 S-4716 DATE TO FROM SUBJECT Muni ality of Anchora MEMORANDUM March l, 1978 Bill Jones - Planning John W. Lynn - Environmental Engineering - DHEP S-4716 Johnnas Woods Subdivision File No.: PB3 T.I~.~ ~~not appr,ove,10 ,125 square feet lo.t_s ' - _ no guarantee of sT~-le-faml]~! ! i ~artment requi res 40~4~O-~r-e--T'6~tS~Tn parcels not having~j)ublic s~le. I ,/ Environmental Engineering ~ r ~ ~-~ ~ //-- 91 010 (4/76) '~,© , Fir. Paul Thomasson 3202 Spenard Road Anchorage, AK 99503 Sub] ect: 4040 "B" STREET, ANCHORAGE, ALASKA 99503 PHONE 907-279-2581 January 20, 1978 W.O. D10759 Grid: 2324 Subsurface Investigation for Proposed Subdivision N1/2 Lot 29, Sectlon 10, T 12 N, R 4 W, Anchorage, Alaska Dear Mr. Thomasson: As requested by ~r. Bob Grler of DOWL Engineers, we have completed the subject investigation. The scope of the investigation includes two tesL holes. Attached with this transmittal are the following: Vlcanlty Map Test Hole Location Sketch Test Hole Logs Explanatory Information Fagure 1 F~gure 2 Table A Sheets 1-3 Exploration was conducted on December 29, 1977. A truck mounted MobJle Drill B-50 rag owned and operated by Denali Drilling was used for the exploration. The r~g was equ!pped wlth a solld f]3ght auger. The test holes were located ~n the field and logged by ~r. O.M. Hatch, geologist w~th Alaska Testtab. Table A is the log of the test holes reftecslng f~etd observations as well as laboratory class~facat~on of the so~ls. The so3! types encountered in the two test holes are similar. So~l condat!ons are expected to be fairly unaform throughout the sl~e. Based on the visual classification of the soils the esti- mated percolat~cn rate as I m~nute/~nch. Because sandy so~ls some%~mas clog ~ith time, we recommend a more conservative value of 3 minutes/!nch o~ 100 square ft./bedroom be used for design of on-slLe sewerage systems. No free water was observed ~n the tesn holes whmle drilling, however, the free water level may fluctuate seasonally and wzth precipitation. Mr. Paul Thomasson January 20, 1978 Page Two We trust the foregoing is sufficient to your present needs. there are any questions or if we can be of further service, please contac% us. Very truly yours, ALASKA TESTLAB R. Mark Hansen If APPROVED BY: ~elvin R. Nichols, P.E. Laboratory Manager RMH:mfm Attachments cc: Robert P. Gr~er AIRPO~.T 35 W £ I GHTY Sb'(TH TEST HOLE LOCATION S~E~CH FIGURE 2 Date: 12-29-77 Logged By: O.M.Hatch Test Pit ~1 Table A WO #D10759 .Depth in Feet From To 0.0 0.5 0.5 5.0 5.0 7.0 7.0 10.0 10.0 16.0 Soil Description Brown Peat and Silt. NFS/F-2, brown Sand, SP-SM, with traces Silt and Gravel, poorly ~raded, damp, medium density. NFS, brown Gravelly. Sand, SP-SM, with trace Silt, damp, medium density, rounded particles to 2" NFS, brown Sand~ Gravel, GW-GM, with trace Silt, well graded, damp, medium density, rounded parti- cles to 3" NFS, brown Gravelly Sand, SW, damp, medium density, rounded particles to 1" Bottom of Test Pit: Frost Line: Free Water Level: 16.0 ft. 1.0 ft. None observed wh~le drilling Sample Depth 1 5.0 2 10.0 3 15.0 Type of Sample unified Classification G SP-SM G GW G SW Remarks: 1. 3. 4. 5. 6. Type of Sample, G=Grab, SP = Standard Penetration, U = Undisturbed. Dry Strength, N=None, L=Low, M=Medlum, H=Hlgh. Group refers to similar material, this study only. General Information, see Sheet 1. Frost and Textural Classification, see Sheet 2. Unified Classification, see Sheet 3. Date: 12-29-77 Logged By: O.M.Hatch Test Pit ~2 Table A WO #D10759 Depth in Feet From To 0.0 I .0 1.0 5.0 5.0 8.0 8.0 11.0 11.0 16.0 Soil Description Brown Peat and Silt, topsoil. NFS/F-2, bro%~ Sand, SP-SM, with traces Silt and Gravel, poorly graded, damp, medium density. NFS, brown Gravelly Sand, SW, well graded, damp, medium density, rounded particles to 2". NFS, brown Sandy. Gravel, GW, well graded, damp, medium density, rounded particles to 3". NFS, bro%~ Sand, SW, with trace Gravel, damp, medium dens~ty, rounded particles to 1". Bottom of Test Pit: Frost L~ne: Free Water Level: 16.0 ft. 1.0 ft. None observed while drilling Sample Depth 1 5.0 2 10.0 3 15.0 Type of Sample Unified Classification G SP-SM G GW G SW Remarks: 1. 3. 4. 5. 6. Type of Sample, G=Grab, SP = Standard Penetration, U = Undisturbed. Dry Strength, N=None, L=Low, M=Medlum, H=Hlgh. Group refers to similar material, this study only. General Information, see Sheet 1. Frost and Textural Classification, see Sheet 2. Unified Classification, see Sheet 3. Test Hole Log -- Description Grade The sod descriptions shown on the logs are the best estimate of the soil's characteristics at the time of held examination and as such do not achieve the precision of a Iaborator} testing procedure If the log includes sods samples, those satnples recelxe an mdep~.ndent textural classification tn the laboratory to verify the field examination The logs often include the follo~smg items Depth Interval - usually shown to 0 I foot within that zone no significant change tn soil t} pe was observed through drill action, direct obaer;atlon or sampling Frost Classification - NFS, Fi, F2, F3, F4, see "Sod Classification Chart" Texture o( Soft - An engineering classification of the soils by particle size and proportion, see "Sod Cla~$1tlcatlon Chart", note the proportions are approximate and modl*lCatlolls tO the soil group due to stratification, Inclusions and changes m properties are mctuded Moisture Content -- this is a qualitative rqeasure d..~, no or little apparent surface damp, moisture forms portion o¢ color, less than plastic limit, ~, no free water, oitcn soft, if cohesive sod, saturate~, f-ce water ma} be squeezed out, Ifa fr,.e draining sell, dllatent at natural moisture content ,f a non plastic silt or fine sand {The moisture conten* :s fu-ther defmedb~ reference to PI, LW, NP, M'% or dflatenc~, ) Denslt) - refers to more or-less nol cohesive sods such as sand gravel mixtures with or without a fine fr,*ct on derived from drdimg action and/or sample data usua.[l~, d~scrlb~d as xe-) loose, loose, medium dense, very dense General intent Is to portray earthwork characteristics Stiffness - refers to more or less cohesive sods and fine grained silts of ~ln. city sdt groups Derived from drilI a,,;on and/or sample data Very soft, soft, stiff, ver5 stiff aud hard are commonl~ used t~rms Particle size - The largest particle recovered b:. the split spoon is 1:318", s'h~lby tube 3", auger flights (l',~'lu~e man) 2' , Auger flights (BI>S0 hollow stein) 6"-8" Larger parttclvs are described indirectly, by action of the drdhng and are retorted to as cobbl~s 3" to 8", or boulders 8"+ Therefore when rexlewmg the gradxuon sheets, if an},, the description on the hole log must be cons:tiered lot an indication of larger particles Unified t, oll Classification - This is a two letter code See Unified C]asslfication sheet for ~-~her deflmtlon In some cases AASHO andlor FAA soil classifications may be sho~n as welt as the un:fled Atterberg Limits - useful for fine grained and other plastic softs PI, natural moisture content behe~ed to be less than plastic limit PI+, natural moisture conlent behevcd to be. betv, een plasnc and hqmd hnnts L~_.Z+, natural moisture content beheved to be greater than liquid bm~t NP, non plastic, useful as a modif}mg descnpuon of some n'~-a t er mis l)dat~n_.~.E -- I~ the ~bibt~ of water to m:b'~te to th~ surface, of a as an I~d to dctcrnllnC if a fmc grained soil Is a ahghtl~ or non plastic Rock flour - finel} ground sell that is not plastic but otherwise appears ~m~ clayt, y s~lt Organic Content ~ usually described as Peat, PT, sometimes includes discrete- particles such as wood coal, eec as a modifier to an Inorganic soft Quantity described as, trace, or an estimate of volume or, in case of all orgamc, - as Peat This may include tundra, muskeg and bog material Muck -- a modifier used to describe very soft, semi orgamc deposits u~ually occurmg below a peat deposit Amorpbus pc, at - organic particles nearly or fuIl~ dlzlntegrated Fibre .us Peat -- organic particles more-or-less nltil~t Bottom of Testhole - includes last sample mter~al Frost Line - seasonal frost depth as described by drdhng action and/or samples at the time of dnllulg Frozen Ground - other than frost line, described by samples, usually includes dcscrlption o! Ice content, often wdl include modified Unllled Classification for frozen soils - this Is a special case related to permafrost studies Free Water Level - The free water level noted during drllhng This is not nec~cssarlt~ the static water table at tile time of drilling or at other seasons Stent water table determination In other than vcr) pcrumable soils requlres obse-vation wells or plczometer Installations, used mil} in special cases Bloc/6" -- The number of blows of a 140 weight free falhng 30" to adx race a 2" split spoon 6' , thc number of blows for a 12" advance bydefmitlon the standard penctratlon ,,4% - natural moisture content of thu sod sample, usually not performed on clean sands or gravels below the water table Type of Sample -- S__P, refurs to 2" spht spoon dr:yen rote the soil by 140 pound weight, a disturbed sample, .~, tbln wall tube "Shelby" used to obtain undtsturl~ed samples of fine grained soil, ,:Ca, "grab" &sturbed sample from auger fhghts or wall of trench, C, cut sample undisturbed sample from wall of trench Dr5 Strength a useful indicator of a soil's clayey frat. t~on, N=None, L=Low, M =M~.dlum, H=H~gh Group - The saInplcs are placed into apparently sm~dar group~ based on color and tcxtnr~ and arc n'bttrarft} assigned a group letter Further disturbed tests lllcludlng Attclbcrg l ImltS gram SILt. nlol~turc dcnslt'~ relanonshlp, otc mW be pulformcd on thc group md are a~sum~.d to SOIL CLASSIFICATION CHART 30% GRAVEL CLAY CLAYEY OR SILTY CLAYEY SILTY /\ CLAYEY CLAYEY SILTY ~ SILTY SAND SAND 0 !0 GRAVELLY SAND x/ x xt GRAVELLY SAND \ 20 30 40 50 GRAVEL (+¢4 SCREEN) GRAVEL SANDY GRAVEL SANDY GRAVEL 60 70 80 % BY WEIGHT 90 100 NONFROST SUSCEPTIBLE SOILS ARE INORGANIC SOILS CONTAINING LESS THAN 3% FINER THAN 0 02 mm GROUPS OF FROST-SUSCEPTIBLE SOILS F1 GRAVELLY SOILS CONTAINING BETWEEN 3 AND 20% FINER THAN 0 02 mm F2 SANDY SOILS CONTAINING BETWEEN 3 AND 15% FINER THAN 0 02 mm F3 a GRAVELLY SOILS CONTAINING MORE THAN 20% FINER THAN002 mm AND SANDY SOILS [EXCEPT FINE SILTY, SANDS) CONTAINING MORE THAN 15% FINER THAN 0 02 mm b CLAYS WITH PLASTICITY INDEXES OF MORE THAN 12 EXCEPT VARVED CLAYS F4 a ALL SILTS INCLUDING SANDY SILTS b FiNE SILTY SANDS CONTAINING MORE THAN 15% FtNER THAN 0 02 mm c LEAN CLAYS WITFI PLASTICITY INDEXES OF LESS THAN 12 d VARVED CLAYS