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HomeMy WebLinkAboutHOMESTEAD HILLS Subsurface Investigation 4040 "B" STREET ~ .~ ,~Cb~l~ t~:CTI ~,~'~ ANCHORAGE, ALASKA 99503 ~(~ ~.1'1~j'1;1~1'1 I~1~ (907) 278-1551 ' ~ W.O.~ D1.0764 ~/~ Grid: 2636 ~ ~ 521 Wes~ ~2n~ ~venue ~noho~age, ~K 99503 Subject: Subsurface Investigation for Proposed Homestead Hills Subdivision Dear Mr. Hoffman: As requested, we have completed the above investigation. The scope of the investigation includes eight test holes and examination of the site for suitability of on-site sewerage systems. Transmitted with the report are the following: Vicinity Map Test Hole Location Sketch Idealized Soil Profiles Test Hole Logs Explanatory Information Grain Size Distribution Curves Figure 1 Figure 2 Figures 3-5 Table A Sheets 1-3 Sheets 4--6 Exploration was conducted February 9 and 10, 1978. A Nodwell mounted B-50 drill rig, owned and operated by Denali Drilling Inc., was used. The rig was equipped with a solid flight auger. Test holes were lccated in the field and logged by Mr. O.M. Hatch, geologist/senior technician with Alaska Testlab. Percolatio~ tests were performed by Mr. Larry Schmidt, technician on the Alaska Testlab staff. Table A is the log of the test holes reflecting field observations and visual classifications of the soils. As samples were recovered, they were sealed in plastic bags to protect the natural moisture content. In the laboratory, the moisture content and dry strength of each sample was determined. Samples of similar color, texture and particle size distribution were grouped together and given an arbitrary group designation. Grain size analysis was performed on composite samples of important groups rather on individual samples. MuNICIpALItY OF ANCHORA(~E D£pARqMENT OF HEAi.~H & F..NVi~ONMFzN]-At PR Mr. Cleone Hoffman February 16, 1978 Page 2 Percolation tests were performed on those holes which, judging from the logs, were expected to have the least favorable percolation rates. The method recommended by the Municipality of Anchorage was used for the tests. Results are as follows: TEST HOLE NO. RATE REQUIRED SQ.FEET/BEDROOM 2 3.3 min./inch 105 3 6.7 min./inch 140 7 5.0 min./inch 125 8 1.0 min./inch 85 The percolation test was attempted on Test Hole No. 8 but the water drained so fast it could not be filled above the 7' depth when carrying water by hand. The rate shown is estimated, based on behavior during the test. No free ground water was observed during exploration. It should be noted that the free ground water may fluctuate seasonally or with precipitation. The idealized soil profiles Figures 3 thru 5 are not drawn to scale and the depth of the test holes is exaggerated with respect to the slope of the ground. Soil conditions between the holes are interpolated, based on similar soils observed in the various test holes. Based on the results of this investigation, the site appears suitable to on-site sewage treatment systems. We trust the foregoing meets your present needs. If you have any questions or if we can be of further assistance, please do not hesitate to contact us. Very truly yours, ALASKA TESTLAB R. Mark Hansen Approved: Laboratory Manager RMH: mfm: lm Attachments MUNiCiPALITY OF ANCHORAGE DEPARTMEN1 OF HLALTH & ENVIRONMENTAL PRO ~ EC~'ION MAR ~L 0 RECEIV~, MUNICIPALITY OF ANCHORAQ~ DEPARTMENT OF HEALTI~ & ENVI[~ONMENTAL MAR 1 0/97'8 RECEIVED MUNiC[i;,"\LITY OF ANCHORAGE DEPARi,MENT OF HEALTH & £NVIRONMENTAk PRO !~C1 ON i978 RECEIVED \ MUNICIF/',LITY OF ANcHoRAGE DEPAR]MENT OF HEALT?~ & ENVIi~ONMENTAL PRO~EC11ON RECEJV~:~ MUNICIPALITY OF ANCHO~,AG'E DEPARTMENT OF ENVIRONMENTAL 197'8 RECEIVED Date: 2/9/78 Logged By: O.M.Hatch Test Hole #1 Table A WO~ D10764 Depth in Feet From To 0.0 0.5 0.-5 1 .5 1 .5 13.0 13.0 16.0 Bottom of Test Hole: Frost Line: Free Water Level: Soil Description Brown Peat, Pt, damp, soft. F-4, brown Sandy Silt, ML, damp, stiff. F-l/F-2, brown slightly Silty Gravelly Sand., SW-SM, to slightly Silty Sandy Gravel., GW-GM, dry, medium density, rounded and subrounded particles to 3" NFS, brown Gravelly Sand, SW, damp, medium density. 16.0 ft. 1.0 ft. None observed while drilling Sample Depth' 1 5.0 2 10.0 3 15.0 Type of Dry M% Sample Strength Group Unified 2.7 G N A SW-SM 4.4 G N A SM 4.0 G N A SW Remarks: 1. Type of Sample, G=Grab, SP = Standard Penetration, U = Undisturbed. 2. Dry Strength, N=None, L=Low, M=Medium, H=IIigh. 3. Group refers to similar material, this study only. 4. General Information, see Sheet 1. 5. Frost and Textural Classification, see Sheet 2. 6. Unified Classification, see Sheet 3. MuNtCIP/',IJTY OF ANCHORAGI~ DEPFRZMENT OF ~{EA~'fH 8, ,ENVI[~ONMENFAL PRr)tt:C ON Test Hole #2 Table A Date: 2~9/78 Logged By: O.M. Hatch WO# D10764 Depth in Feet From To 0.0 1 .0 1 .0 3.0 3.0 8.0 8.0 16.0 Soil Description F-4, brown Sandy Silt, ML, damp, stiff, NP. F-2, brown Silty Sand, SM, medium and fine grained, damp, medium density. F-2, brown Silty Gravelly Sand, SM, damp, medium density,"-subround~d particles to 2" F-4, brown Gr._.avellv Sandy Silt, ML, damp, stiff, NP, subround'ed particles to 3" Bottom of Test Hole: 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 Dry M% Sample Strength Group Unified 6.5 G N B SM 14.0 G L C ML 17.7 G L D ML Remarks: 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. Date: 5/9/78 Logged By: O.M.Hatch Test Hole #3 Table A WOIt D10764 Depth in Feet From To 0..0 1 .0 1 .0 5.0 5.0 16.0 Soil Description Brown Peat, Pt, damp, soft. F-4, brown Sandy Silt, ML, damp, stiff, NP, F-4, brown slightly Gravelly Sandy Silt, ML, damp, stiff, NP. Bottom of Test Hole: Frost Line: Free Water Level: 16.0 ft. 0.5 ft. None observed while drilling Sample Depth 1 5.0' 2 10.0 3 15.0 Type of Dry ~.% Sample Strength Group Unified 13.9. G L C ML 11.2 G L C ML 18.9 G L D ML Remarks: 1. Type of Sample, G=Grab, SP = Standard Penetration, U = Undisturbed. 2. Dry Strength, N=None, L=Low, M=Medium, H=High. 3. Group refers to similar material,' this study only. 4. General Information, see Sheet 1. 5. Frost and Textural Classification, see Sheet 2. 6. Unified Classification, see Sheet 3. MuNIC~I:/',[IZY OF ANcHOrAGE DF~PARqM:'F'41' OF ti[.'A'IT~ ~ fNVi~©NM~NTAL PRO ~ I:C I ION Date: 2/9/78 Logged By: O.M. Hatch Test Hole #4 Table A WO# D10764 Depth in Feet From To 0.0 1 .0 I .0 4.0 4.0 10.0 10..0 16.0 Soil DescriPtion Brown Peat, Pt, damp, soft. F-4, brown Sandy Silt, ML, damp, stiff, NP. F-4, brown Gravelly Sandy Silt, SM to ML, damp, stiff, NP, subrounded particles to 3~' F-4, brown Sandy Silt, ML, with trace, gravel, damp, stiff, NP. Bottom of Test Hole: 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 Dry M% Sample. Strength Group Unified 9.8 G N B SM 10.4 G L C ML 14.3 G L-M C ML Remarks: 1. Type Qf Sample, G=Grab, SP = Standard Penetration, U = Undisturbed. 2. ~ Dry Strength, N=None, L=Low, M=Medium, H=High. 3. Group refers to similar material, this study only. 4. General Information, see Sheet 1. 5. Frost and Textural Classification, see Sheet 2. 6. Unified Classification, see Sheet 3. IpALITY OF ANCHORAGE Date: 2/10/78 Logged By: O.M. Hatch Test Hole #5 Table A WOI~ D10764 ~pth in Feet From To 0.0 1 .0 0.5 5.0 5.0 13.0 13.0 16.0 Soil Description Brown Peat, Pt, dam~, soft· F-4, brown Sandy Silt, ML, with trace gravel, damp, stiff, NP. F-2, brown Silt~ Gravelly Sand, SM, with NFS Gravelly Sand, SW, layering, damp, medium density, rounded and subrounded particles-to .3" F-4, brown Sandy Silt, ML, with trace Gravel, damp, stiff, NP. Bottom of Test Hole: 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 Dry ~% .Sample Strength Group~ 15·5 G L C 6.0 G N A 11 .0 G L C Unified ML SW-SM ML Remarks: 1. 3. 4. 5. 6. Type of Sample, G=Grab, SP = Standard Penetration, U = Undisturbed. D~y Strength, N=None, L=Low, M=Medium, H=HJ. gh. 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: 2/10/78 Logged By: O.M. Hatch Test Hole #6 Table A WO# D10764 Depth in Feet From To 0.0 0.5 0.5 1 .5 1 .5 8.0 8.0 16.0 Soil Description Brown Peat, Pt, damp, soft. F-4, brown ~andy Silt, ML, damp, stiff, NP. F-2, brown Silty Gravelly Sand, SM, damp, medium density, rounded and subrounded particles to 2" F-4, brown Sandy Silt, ML, with trace gravel, damp, stiff, NP. Bottom of Test Hole: Frost Line: Free Water Level: 16.0 ft. 0.5 ft. None observed while drilling Sample Depth' 1 5.0 2 10.0 3 15.0 Type of Dry .'.~ Sample Strength Group U~if.ied 4.9 · G N B /~ 10.3 G N B 13.1 G L C 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. Date: 2/10/78 Logged By: Q.M. ttatch Test Hole a7 Table A WO# D10764 Depth in Feet From To 0.0 0.5 0.5 2.5 2.5 9.0 9.0 16.0 Soil Description Brown Peat, Pt, damp, soft. F-4, brown Sandy Silt, ML, damp, stiff, NP. F-2, brown Silty Gravelly Sand, SM, damp, medium density, rounded and subrounded particles to 2". F-4, brown Sandy Silt, ~,~, with trace gravel, damp, stiff, NP. Bottom of Test Hole: Frost Line: Free Water Level: 16.0 ft. 0.5 ft. None observed while drilling Sample Depth I 5.0 2 10.0 3 15.0 Type of Dry M% Sample Strength Group Unified 5.7 G N B SM 11.7 G N-L B ML 18.7 G L C ML 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 #8 Table A Date: 2/10/78 Logged By: 'O.M.Hatch WO# D10764 Depth in Feet From To 0.0 1.0 1 .0 4.0 4.0 14.0 14.0 16.0 Bottom of Test Hole: Frost Line: Free Water Level: Soil Description Brown Peat, Pt, damp, soft. F-4, brown ~andy ~il~, ML, damp, stiff, NP. F-2, brown slightly Silty Gravelly Sand, SW-S~.t~ ~ damp, medium density, rounded to subrounded particles to 2" 16.0 ft. 0.5 ft. F-4, brown Sandy Silt, ML, with trace Gravel, damp, stiff, NP. None observed while drilling Sample Del}th 1 5.0 2 10.0 3 15.0 Type of Dry ~% San~ple Strength Group 4.4 G N A 5.4 G N A 11.4 G L B Unified - SM Remarks: 1. Type of Sample, G=Grab, SP = Standard Penetration, U = Undisturbed. Dry Strength, N=None, L=Low, M=Medium, H=Hiqh. Group refers to similar material, this study only. General Information, see Sheet 1. Fros~ and Textural Classification, see Sheet 2. Unified Classification, see Sheet 3. MuNiCiPALiTY OF ANcHOP. AGI~ D~PA~TK,~NT OF H~AI..TH & F~Nx/Ii(ONK/&NTAL PRO i'~cTiON Test Hole Log - Description Guide The soil descriptions shown on tile logs arc thc best estimate of thc soil's characteristics at the tittle of field ex,tmJllatiou and as such do oat achieve the precision of a laboratory testing procedorc. If the log includes soils samples, those samples receive an independent textural classification in the laboratory to verify the field examination. The logs often include the following items: Depth Interval - usually shown to 0.1 foot, within that zooe no significant change in soil type was observed through drill action, direct observation or sampling. Frost Classification -- NFS, FI, F2, F3; F4, see "Soil Classification Chart" Texture of Soil - An engineering classification of tile soils by particle size and proportion, see "Soil Classification Chart", note the proportions arc approximate and modifications to tile sail group due to stratification, inclusions and changes in properties are included. Moisture Colltent ~* this is a qualitative measure: d~rv, no or little apparent surface moisture, damp, moisture fornls portion of cok)r, less than plastic limit, wet. no free w,lter, often soft. if cohesive soil, saturated, free water may be squeezed out, ifa free draining soil; dilatcnt at ll·lttlral moisture content, if a non-plastic silt or fine sand. (The moisture content is further definedby reference to PI, LW, NP, M',';~ or ditatency.) _Density - refers to more-or-less TIOH-collesiVR soils~ such as saIld g~avel mixtures with or witilout a fine fiaction, derbcd flora drilling action and-Jot sample data: usually described as: very loose, loose, medium dense, very dense. General intent is to portray earlbwork characteristics. Stiffness -- refers to more-or-less cohesive soils and fine grained silts of ~ clay-silt groups. Derived from drill action and/or sample data. Very soft, soft, stilT, very st ff uld 1 rd are colllmOllIy used tellll$. Particle size - The largest particle recovered by the split spoon is 1-3/8", Shc-lby tube 3", auger flights (minute-man) 2", Auger /lights CB-50 hollow stem) 6"-8". Larger particles are described indirectly by action of the drilling and are relerred to as cobbles, 3" to 8", or boulders 8"+. Therefore when reviewing the grfidation sheets, if any, the description ou the hole log must be considered for an indication of larger particles. Unified Soil Ciassificatiou -- This is a two letter code. See Unified Classification sheet l'uT-i=~r]her definition, ltl some cases AASHO and/or FAA soil classifications ma}' be shown as well as the unified. Atterberg Limits- useful for fine grained and other plastic softs. P_~Ii natural moisture content believed to be less than plastic limit PI+; natural moisture content believed to be between plastic and liquid limits L~v+; natural moistuxe content believed to be greater than liquid limit N.~P; non-plastic, useful as a modifying description of some silty materials, l_)_ila._~3'~c~ -- is the ability uf water to migrate to the surface of a saturattyd or nearly saturated soil sample wheu vlbr:*tcd or jolted - used a~ an oki to determine if a fine grained soil is a slightly or non-plastic silt or a volcanic ash. P, ock flour --: finely ground soil that is not plastic but otherwise appear~ sTfifilar tb-i clayey silt, Organic Content - usually described as Peat, PT, sometimes include ~ ~ such as wood, coal, etc. as a modifier to an inorgani, soil. Quantity described as; trace, or an estimate of volume, or, in case of all organic, -- as Peat. This may include tundra, muskeg and bo~ material. Muck - a modifier used to describe very soft, senti-organic deposit5 ~fly occuring below a peat deposit· Amorphus peat -- organic particles nearly or fully disintegrated. Fibrous Peat - organic particles more-or-less intact. Bottom of Testhole -- includes last sa~nple interval. Frost Line - seasonal frost depth as described by drilling action and/o: ~mple$ at the time of drilling. Frozen Ground - other than frost line, described by samples, usuali5 includes d~scription of ice content, often will include modified Unifier Classification for frozen soils ~ this is a special case related to' permafrost studies· Free Water l.evel - The free water level noted during drilling. Thisi, not necessarily the static water teble at the time of drilling or at ~tbe~ scasolls. Static water table derernlinauon in other than very perlneabl( soils requires observation wells or piezumctcr installations, u=cd only it special cases. Blow/6" - The number of blow~ ora 140 weight flee falling 30" tc advance a 2" split spoou 6"; the number of blows for a 12" advance is by definition, dm standard penetration. ~M,% - natural moisture content of the soil sample, usually no~ performed on clean sands or gravels below the water table. Type'oCSam~Je - SI~, relers to 2" split spoon driven into the soil by 140 pound weight, a disturbed samp}e, ~; thin wall tube. "Shelby" used to obtain undistmbed sample, of fine grained soil, ~, "grab" disturbed ~ample from auger flights or wall of trench ~, cut sample, undisturbed sample from wall of trench. Dry Streng~!2 - a useful indicator of a soil's clayey fraction, N=None. L=l. ow, M=Medium, H=ltigh Grou~ -- The samp]esare placed into apparently similar groups base~; disturbed ~ests including Attesbe~g Limits, grain ~ze, moisture-dcnslt) MLJNICIRALITY OF ANCHORAGE DEPART~v~F~NT OF HEALTH & ENVIRONMENTAL PRO1 ECTION /978 RECEIVED SOIL CLASSIFICATION' CHART 30% GRAVEL CLAY OR SILTY SAND CLAYEY CL'AVEY /ii~ CLAYEY / / 0 R ~'~_.i! ."~//0 R CLAYEY SILTY/~ iJ T k / ~i~ k SILTY / GRAVEL GRAVELLY SAND SANDY GRAVEL \/ ., \ SAND GRAVELLY SAND SANDY GRAVEL GRAVEL / \ \ 0 10 20 30 40 50 60 70 80 90 100 GRAVEL (+=4 SCREEN) % BY WEIGHT NONFROST SUSCEPT BLE SOILS ARE INORGANIC SOII_S CONTAINING LESS THAN 3% FINER THAN 0.02 mm. GROUPS OF FROST-SUSCEPTI 3LE SOILS: F! GRAVELLY SOILS CONTAINING BETWEEN 3 AND 20% FINER THAN 0.02 mm. F2 SANDY SOILS CONTAINING BETWEEN 3 AND ]5% FINER THAN 0.02 mm. F3 a. GRAVELLY SOILS CONTAINING MORE THAN 20% FINER THANO.02 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. ALLSII_TS INCLU]ING SANDY SILTS. b. FINE SILTY SANDS CONTAINING MORE'THAN 15% FINER THAN 0.02 mm. c. LEAN CLAYS WITH PLASTICITY INDEXES OF LESS THAN 12. d. VARVED CLAYS. MuNtCIFW-ITY OF ANCHORAGE DEPARiM'd~T OF HEALTH & ENVh~ONMENTAL pRO'1~C'I ION M~JNICIPALITY OF A'NCHORA(~I~ DEPARTMENT OF HEAt. TH & ENV hR ONIv'~ENTAL PROI EC~ION pii:~,~R '.1. 0 !978 RECEIVED MUNICIPALITY OF ANCHORAGE DEPARTMENT OF HEALTH 8, ENVIRONMENTAL PRO'l 8C~ION /978 RECEIVED MUNICIPALITY OF ANCk~ORAGF~ DEPARTMENT OF HEALTH ENVII~ONMENTAL PROTECTIOI'~ 1978 MUNICIPALITY OF ANCHORAGE DEP/',R]MEN1 OF HEALTH & ENVIRONMENTAL PRO I'ECTION 197'8 RECEIVED MUNICIPALITY 01: ANCHORAGE: DEPARI'MF_NT OF HEALTH & ENVIt(ONMENTAL PRO I'ECTION MAR 1 0 1978 RECEIVED j53' 0-6 8-5 ,~RACT B ~ 44,555 S.E 44,535 S,F/ Ch~rma~ ..... 1978, HOMESTEAD HILLS SUBDIVIS'ION NO. 1, L.I-18, BLK. 5 8~ TRACT B, BLK. 1 SUBDIVISION OF TRACT A, HOMESTEAD HILLS SUBD. DICKINSON OSWALD: WALCH · LEE ANCHORAGE, ALASKA REF, 82--36 .... We hereby certlf~, ~hat we ~,,e the owners oF tho prope,ty shown and 25,065 s~tl i~ii easements fo~ pub~;c utilities, roadways and e~le~s Jed~ed by us for J~ Dubl~c use, ' .... I NOTARY'S ACKNOWLEDGMENT ,~ KOHL il Subscribed amd sworn before me thLs ~!~.:~ ........... 971 -~ ~ ~a¢~ ..... ,C ~, ~ I ...... L I, thk 6Kderslgned reglsfered engfneer or surveyor, hereby certify ~h~t ~ j PL AT Of ¢ %c, HOMESTEAD HILLS I LEGENJ NOTE: C0UTA~mN~ ~5 ACRES,~0RE 0R LESS