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Home My WebLink AboutJOHNNA'S WOODS Lots 1 thru 3 Plat# 78-140 & 70-308 S-4716 DATE: TO: FROM: SUBJECT: mc,pM ty of Ancho e MEMORANDUM ~larch 1, 1978 Btll Jones -Planntng John W. Lynn - Envtror~ental Engineering - DHEP 5-4716 Johnnas Woods Subdtvtslon File ~o.: PB3 T~, r~e~t cannot approve 10,125 square feet lots - no guarantee of single-fa.~!!in~~art~ent requires 4 ee n parcels not having~oubltc sewer and .alit t. va!!-_hle. ~'Enviro~ental Engineering ~,O~O ~C 91.010 (4/76) /"= :TO ~ .~ 4040 "B" STREET, ~'~ ANCHORAGE, ALASKA 99503 PHONE: 907.279.2581 January 20, W.O. D107~9 Grid: 2324 1978 ~. Paul Thomasson 3202 Spenard Road Anchorage, AK 99503 Subject: Subsurface Investigation for Proposed Subdivision N1/2 Lot 29, Section 10, T 12 N, R 4 W, Anchorage, Alaska Dear ~. Thomasson: As requested by Mr. Bob Grier of DOWL Engineers, we have completed the subject investigation. The scope of the investigation includes two test holes. Attached with this transmittal are the following: Vicinity Map Test Hole Location Sketch Test Hole Logs Explanatory Information Figure 1 Figure 2 Table A Sheets 1-3 Exploration was conducted on December 29, 1977. A truck mounted Mobile Drill B-50 rig owned and operated by Denali Drilling was used for the exploration. The rig was equipped with a solid flight auger. The test holes were located in the field and logged by Mr. O.M. Hatch, geologist with Alaska Testlab. Table A is the log of the test holes reflecting field observations as well as laboratory classification of the soils. ~ne soil types encountered in the two test holes are similar. Soil conditions are expected to be fairly uniform throughout the site. Based on the visual classification of the soils the esti- mated percolaticn rate. is 1 minute/inch. Because sandy soils sometimes clog %:ith time, we recommend ~ more conservative value of 3 minutes/inch or 100 square ft./bedroom be used for design of on-site sewerage systems. No free water was observed in the test holes while drilling, however, the free water level may fluctuate seasonally and with precipitation. ~. Pa~l Thomasson January 20, 1978 Page TWO We trust the foregoing is sufficient to your pre~ent needS. · If there are any questions or if we can be of further service, please contact us. Very truly yours, ALASKA TESTLAB R. Mark Hansen APPROVED BY: M~lvin R. ~ichols, P.E. Laboratory Manager RMH:mfm Attachments cc: Robert P- Grief !INTI?. ~-.'fiTlO,*¢: I. i VlClrJ,Ty J~.']AI::) FJO. }. W...__~. i GHTY SIXTH. W. EIGHTY EIGHTH I I I I TEST I]OL~. LOCAT~[O~I SK~TCLt FZGUR~ 2 Date: Logged By: 12-29-77 O.M.~{atch Test Pit ~1 ~epth in Feet From To 0.0 0.5 0.5 5.0 5.0 7.0 7.0 .10.0 10.0 16.0 Table A WO ~D10759 Soil Description Brown Peat and Silt. NFS/F-2, brown Sand, SP-SM, with traces Silt and Gravel, poorly g-~ed, damp, medium density. NFS, brown Gravell[ Sand, SP-SM, with' trace Silt, damp, medium density, rounded particles to 2". NFS, brown Sandy Gravel, GW-GM, with trace Silt, well graded, damp, m~um density, rounded parti- cles to 3". NFS, brown Sand, damp,'medium Gravelly ~ SW, density, rounded particles to 1". Bottom of Test Pit: Frost Line: 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. e 3. 4. 5. 6. Type of Sample, G=Grab, SP = Standard ~enetration, U = Undisturbed. Dry Strength, N=None, L=Low, M=Medium, ~I=}ligh. 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: Logged By: 12-29-75 O.M.l{atch Test Pit ~2 Table A WO %D10759 Depth in Feet From To 0.0 1.0 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 San~ Gravel, GW, well graded, damp, medium dens~t~-~, rounded particles to 3". NFS, brown Sand, SW, with tra~e Gravel, damp, medium dens~-t~, rounded particles to 1" Bottom of Test Pit: Frost Line: Free Water Level: 16.0 ft. 1.0 ft. None observed %~hile drilling Sample 'Depth I 5.0 2 10.0 3 15.0 Type of Unified Sample Classification G SP-SM G GW G · Remarks: 1. 3. 4. 5. 6. Type of Sample, G=Grab, SP = Standard Penetration, U = Undisturbed. ' Dry Strength, N=None, L=Low, M=Medium, H=High. 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 Guide The soil descriptions shown on the logs arc the best esrimatc of thc soil's characteristics at the ti~n¢ of fie!d examination and as such do not achieve the precision of a I'borarory testing procedure. If the log includes soils samples, those lamples receive an independent textural classification in the laboratory to vetlfy the field examination. The logs often include the following items: Depth Interval -- usually shown to 0.1 foot, within that zone no signi£acant change in soll type was observed through d~ill action, dkecc ob~rvation or sampling. Frost Classification -- NFS, Fl, F2, Fa, F4, ~ee "Soil Classification Chart" Texture of Soil - An engineering classifi:ation of the soils by particle size and proportion, ~e "Soil Classification Chart". note the proportions ate approximate and modi.~lcations to the soil group due to stratification, inclusions and changes in properties are included. ~.1oisture Content -- this is a qualitative measure: p, moisture fo: ms port ion or' cot. or, less Ihan plastic limit, land. (The moisture tomcat is further defined by reference to PI, LW. NP, M% or dila[enc)'.) mixcmes with or without a fine fraction, derived &om drilling action and/or sample data: usually dcscrib*'das: very loose, loose, medium · the clay-silt groups. Dcri%'cd ftom dri|l ~ction and;or sampl~ d~ca. Very ParHclc site '- The largest particle t¢c~vercd by the split spoon ,l-a/~'~by tube 3", auger fl~ghcs (~nu[e-manJ 2", Auger (B-SO hollow stem) 6"-8'. Latter parc[cl:s are describe~ ind~ecfly by action of lite dr~ling and are ic(ctr~ lo dS coSb:cs. 3" to 8". or bound:ts 8"+. Therefore when teviewin~ ~hc gradadun'shcets, if any. larger ~tlicle~ United ~oil Cl~ss~cation -- This is Classification s~ct (ur ~her definlrion. In some c~'s AASHO and;or FAA ~il classificaHons m~y be shown ns wc:l as the united. Atle~ber~ Limits - u~ful ~ot ~ine gr~ioe~ an~ other plastic ~ils. .on-plastic, useful as a modifying description of some silty ~tc~ials. Rock flour - finely ground soil that is uot plastic but otherwise appea~s Organic Content -- usually described as Peat, PT. sometimes includes discrete particles such as wood. coal. etc. as a modifier lo an inorganic soil. Quantity described as; trace, or an estimate of volumc, or, in case of ail organic, -- as Peat. This may include tundra, muskeg and bog material. I~uck - a modifier u~d Io describe very soft, semi-organic deposits usually occuring below a peat deposit. Amorphus p~at - organic perticlcs nearly or full)' disintegrated. Fibrous Peal -- organic particles more-or-less inLict. Bottom ofTesthole I includes isst sample interval. Frost Line -- seasonal frost depth as described by drilling action and/or r~mplcs at the time of drilli.g. Frozen Ground -- other than frost line. described by samples, usually includes description of ice content, often will include modified Unified Cisssificacion for frozen soils - this is a special case related to permafrost studies. .Free Water Level -- The free water level noted during dtilliog. This is not neccssardy the static water taldc at the time of drilling or at other special cases. .Blow/f/' I The number of blows of a 140 ,*'elght free falling 30" to advance a 2" split spoon 6"; the number of blows for a 12" advance is. natural moisture content bf the roll sample, usually not p-~r formed on clean lands ot gravels below the water table. Type of Sample - ~P, refers to 2" split spoon driven into die soil by 140 Found weight, a disturbed sample, l · g, Illin svall tube, "Shelby" u~ed lo'obtain undisturbed samples ' of fine grained soil, ~, "grab" disturbed samlile flora auger ~ighls or wall of trench. ~. cut sample, undisturbed ~mple ftom wall o~ trench. Dry .gtrcn~ris - a useful i,dicacor of a soil's clayey fraction, N=None, SOIL CLASSIFICATION CHART -"10% GRAVEL CLAYEY CI.~YEY \ OR~ CLAYEY CLAYEY 3R 51LTY SI LTY ~OR SAND X GRAVELLY SAND SANDY GRAVEL \/ \/ \ / IX' / SAND GRAVELLY SAND GRAVEL iRAVEL GRAVEL 10 20 30 40 50 60 70 80 90 lu0 GRAVEL (+--4 SCREEN) % BY WEIGHT N~)NFROST SUSCEPTIBLE SOILS ARE INORGANIC SOILS CONTAINING LESS THAN 3% FINER THAN 0.02 mm. GROUPS OF FROST-SUSCEPTIBLE .SOILS: GRAVELLY SOILS CONTAINING BETWEEN 3 AND 20=.'~ FINER THAN 0.02 mm. F2 SANDY 5OILS CONTAINII~:O DETWEEN :3 AND 1§% FI,~IER THAN 0.02 mm. F3 a. GRAVELLY SOILS CONTAINING MORE THAN 20% FI~ER THAN 0.02 mm. AND SANDY SOILS (EXCEPT FINE SILTY, SANDS) CONTAINING MORE THAN 15% FINER THAN 0.02 mm. b. CL~YS WITH PLASTICITY INDEXES OF MORE THAN 12. EXCEPT VARVED CLAYS. F4 a. ALL SILTS INCLUDING SANDY SILTS. b. FINE SILTY SANDS CONTAININC t,¶ORE THAN 15% FINER THAN 0.02 mm. ¢. LEAN CLAYS WITH PLASTICITY INDEXES OF LESS ~'HAN d. VARVED CLAYS. UNIFIED SOIL CLASSIFICATION SYSTEM -)