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HomeMy WebLinkAboutTALUS WEST Soils Report· October 13, W. O. 12134 Tryck, Nyman & Hayes 740 "I" Street Anchorage, Alaska 99501 1971 ATTENTION: Mr. Dan Chapman Gentlemen: In response to your recent request, ten (10) test pits have been excavated at Talus West Subdivision, per the attached location sketch, see Figure A. Test pits were excavated by backhoe to approximately 12 to 14 feet. We have reviewed the field data; and test pit logs, sheets 1 through 10, are attached, together with explanatory sheet, in- dicating our drilling and classification procedures. Soil grab samples hav~ been visually classified and in addition, given frost susceptibility and unified soil classifications. Soils consist generally of an upper layer of approximately five- tenths of a foot of peat, and underlying that, a layer of reddish brown silt averaging about two feet in depth. Soils beneath this consist mainly of silty materials---silty gravel, silty sand---with numerous cobbles and boulders encountered. In general, most of the soil at depth, except a few specific instances, could be classi- fied as very silty sand and gravels, or gravelly or sandy silt. Water was encountered during drilling in Test Pit 7 at approx- mately six feet. No other water was noted on the test-hole logs. An~additional enclosure for your use is the Borough Health Depart- ment seepage pit requirements for soils of various classification. If we can be of further help with respect to this subdivision, please call. Sincerely, ames L. S6heffel- Staff Engineer TLS:id Encs. .! CLIENT PROJECT T.H. TN&H Talus West Subd. ~/ 1 ELEV. SIII£ET 1 OF DATE 7 October 1971 W.O. NO. 12134 Existin~ Ground .5 F-4, Brown, Peat, Damp, PT ~-- F-4, Reddish-Brown, Silt, Damp, ML __ ~ Grab Sample F-2, Brown, Silty Gravelly Sand, Dry, Occasional -- Cobbles, Max. Size 6", SP !~ ---- )' F-4, Brown, Sandy Gravelly Silt, Dry, Few Cobbles, --__ Nax. Size 6", ML ~, ~ Grab SAmple 9~ __-- F-4, Brown, Slightly Sandy Gr~.velly Silt, Dry, __ Many Cobbles, blax. Size 8", ML -- ~, ~ Grab Sample Bottom Of Hole 14.0' CLIENT TN&H PROJECT Talus West Subd. DATE 7 October 1971 W.O. NO... 12134 5' F-4, Brown, Peat, Damp, PT F-4, Reddish-Broom, Silt, Damp, ML ~ Grab Sample F-4, Brown, Very Fine Sandy Silt, Dry, Trace Of Fine Gravel, SM F-3, Brown, Slightly Sandy Sil~y Gravel, Dry, Few Cobbles, GP M Grab Sample ~" -- F-3, Brown, Sandy Silty Gravel, Dry, Cobbles, GM -- M Grab Sample ~-~'-~ -- Bottom Of Hole 13.0' T.H. t~ 2 ELEV. Existin~ Ground CLIENT TN&I{ DATE 7 October 1971 PROJECT Talus West Subd. . W.O.NO. 12134 T.H.. ~/ 3 ELE%~. Existing Ground F-4, Brown~ Peat~ Damp~ PT F-4, Reddish-Brown, Silt, Damp, ML -- Grab Sample NFS, Brown, Slightly Silty Sandy Gravel, Dry~ -- Well-Graded, GW F-4, Brown, Slightly Gravelly Sandy Silt, Dry, ML -- Orab ~ample ;175-- -- F-4, Brown, Sandy Gravelly Silt, Dry, ML -- - Grab Sample Bottom Of Hole 13.5' CLIENT TN&H PROJECT Talus West Subd. DATE 7 October 1971 W.O. NO. 12134 ELE~ Existin~ Ground .. Fl4, Brown, Peat, Damp, PT F-4~ Reddish-Brown, Silt~ Damp, ML ), [~ Grab Sample F-2, Brown, Slightly Gravelly Silty Sand, Dry, -- .Few Cobbles 6" To 8", SM _J~ Grab Sample -- F-2, Brown, Graveliy Silty Sand, Dry, Many Cobbles --- & Some Boulders 6" To 14", SM -- ~ Grab Sample Bottom Of Hole 14.0' I -- CLIENT TN~ PROJECT Talus West Subd. DATE. 7 October 1971 W.O. NO.. 12134 T.H. ELEE Existing Ground ., F-4, Brown~ Peat, Damp, PT -- F-4, Reddish-Brown, Silt, Damp, ML )' NFS} Brown, Gravelly Sand, Damp, Few Cobbles 6" To 8 SW ~ Grab Sample F-4, Brown, Slightly Gravelly Sandy Silt, Dry, ML ~ Grab Sample ~7%-- F-4, Brown, Gravelly Sandy Silt,. Dry, ML -- ~ Grab Sample Bottom Of Hole 14.0 CLIENT TN&H ~/ I)ATE 7 October ~971 . PROJECT Talus West Subd. W.O.NO...12136 T.H.. ~/ 6 ELEV. ~isttng Ground F-4, Brown, Peat, Damp, .PT F-4, Reddish-Brown, Silt, Damp, ML F-l, Brown, Silty Sandy Gravel, Dry, GW., -.~ Grab Sample NFS, Grey, Fine Sand, Dry, SP -- Grab Sample NFS, Grey, Medium Sand, Dry, SW - _ Grab Sample Bottom Of Hole 13.0' " CLIENT PROJECT Talus West Subd. T. ~. October 1971 W.O. NO. 12134 Existin8 Ground 3' F-4, Brox~n~ Peat, Damp, PT F-4, Reddish-Brown, Silt, Damp, ML F-4, Brown, Gravelly Sandy Silt~ Damp, Some Water @ 6.0', ML M Gr~ S~mple q,~O F-4, Brown, Sandy Silt, Dry, Trace Of Gravel, ML :. ['~ Grab Sample NFS, Brown, Fine To Medium Sand, Dry, SP/SW ~ Gr~b S~m~le lq~ Bottom Of Hole 13.0' , , / X SttEET 8 OF CLIENT TN&~ ~_X~ "~DATE, ? October 1971 PROJECT Talus West Snbd. W.O.NO., 12134 T.H. $ 8 _ELE~ Existing Ground F-4, Brown, Peat, Damp, PT F-4, Tan, Gravelly Sandy Silt, Damp, ML G=ab Sample %~'~ F-4, Tan, Sandy Gravelly Silt, Dry, Many Gobbles Some Boulders, Max. Size 40", ML F-4, Tan~ Sandy Silt, Dry, Few Gobbles & Boulders~ Max. Size 12"~ ML Grab S~mple 7~ Bottom Of Hole 14.5' CLIENT TN(~j PROJEC']' Talus WesE Subd. October W.O. NO. 12234 1971 T.H. ~ 9 ELE~ Existing Ground F-4, Brown~ Peat~ Damp, PT F-4, Reddish-Brown, Silt, Damp, ML F-4~ Brown, Sandy Silt, Dry, Trace Of Gravel, ML Grab Sample ~ F~4, Bro~m~ Sandy Silt, Dry, ML %,~ F-2, Brown, Slightly Gravelly Silty Sand, Dry, SP Grab Sample .... Bottom Of Hole 13o5~ CLIENT TN~ PROJECT Talus West Subd. SIIEET 10 O1,' DATE 7 October W.O.NO.. 12134 1971 T.H.. ~ I0 ELEKExisttng Ground .§, F-4~ Brown, Peat, Damp, PT F-4, Reddish-Brown, Silt, Damp, ML -- 5' F-4, Brown~ Sandy Gravelly Silt, Damp, Nany Cobbles- & Some Boulders 6" to 10"~ ML [~ Grab Sample Z7q-~-~ -- F-4, Brown, Silty Gravelly Sand, Dry, Occasional Z Gobbles, Max. Size 6,,, SM __ [~ Grab Satrap la ~,~0, ~ o, F-4, Brown, Gravelly Silty Sand, Dry, Sit Z ~'~O ), ~- Grab Sample Bottom Of Hole 13.0' -- ~2 I CLIENT q'N&N DATE, ~4 October ~97l ~ PROJECT Talus West SUbd. W.O.NO. 12134 m T.H. ~ ~ .ELEK...~isting G~ound' ~t 12, Block F-4, Brown~ Peat, Damp, PT F-4, Reddish-Brown, Silt, Damp, ML NFS, Brown, Gravelly Sand, Damp, Occasional Cobbles, Subround~ Haxo Size 6", SP F-4, Brown, Sandy Silt, ~y, ML ~ttom Of Hole 12.0' 0 0 PER CENT COARSER BY WEIGHT 'ri:ST HOLE LOGS SOIL DESCR~PTIQNS The soil descriptions shown on the logs are the best estimate of the soil characteristics 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"). Density - 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 Llmit, see PL Dilatency - 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 predomi- nately a clay or silt. 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 thread test in which a 2" diameter ball of the Sand-Silt-Clay fraction is dropped 2' until a 1" thick pat develops. The diameter of a 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 indicates clays and iow 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 oonverted to an observation well. Capillary Fringe - change from moist to very damp, or saturated soil, usually indicates that water table Is close. Peat - Fibrous material of macroscopic and microscopic fragments of decayed vegetable matter; very compressible, unsuitable for foundation or embankment. Color light brown to black. Ao - The upper layer, surface soil or topsoil, containing humus and/or organic debris, not satisfactory for foundations. ALASKA TESTLAB ASKA TESTLAB 'CONSULTATION · TESTING · EXPLORATION · CHEMICAL · MATERIALS · INSPECTION SOIL CLA', ~ICATION CHART :50% GRAVEL x CLAYEY CLAY EY \ OR SILTY SI LTY \ \ SAND \ \ ~DY \GRAVEL \ GRAVELLY SAND iRAVEL 0 I0 20 50 4.0 50 60 70 80 90 100 GRAVEL (-t-=#=IOSCREEN) % BY WEIGHT NONFROST ,SUSCEPTIBLE SOILS ARE INORGANIC SOILS CONTAINING LESS THAN :5% FINER THAN O. 02mm. GROUPS OF FROST-SUSCEPTIBLE SOILS: FI F2 F$ b. F4 b. d. GRAVELLY SOILS CONTAINING BETWEEN ;5 AND 20°/o FINER THAN O.02mm. SANDY SOILS CONTAINING BETWEEN :~ AND 15% FINER THAN 0.0~' mm. GRAVELLY SOILS CONTAINING MORE THAN 20% FINER THAN O.02mm. AND SANDY SOILS (EXCEPT I=INI[: SILTYt SANDS) CONTAINING MORE THAN 15% FINER THAN O,02rnm. CLAYS WITH PLASTICITY INDEXES OF MORE THAN 12. EXCEPT VARVED CLAYS. ALL SILTS INCLUDING SANDY SILTS. FINE SILTY SANDS CONTAINING MORE THAN 15% FINER THAN O.02mm. LEAN CLAYS WITH PLASTICITY INDEXES OF LESS THAN I2. VARVED CLAYS. SOIL ChA~,.A~.~.P >7.C~ A. ~W (well graded gravel and send) B. G~I (silty, sandy gr~vel) II~ Sands. A. SW (well graded sands ano gravel) B. SP (poorly graded'sends) C. S!4 (silty sands) 125 150 25O III. Silts A. [.;L (silt, fine 275 IV. Clays A. Cll (cia{y, ~i1~ a:',d mix) 350 In an attempt to come up with an eq6itable me%hod of determining soil percolation characteristics and still have figures that the Department can use to compute seepage pit size requirements, the following is prO- posed: , The amount of side wall area required for each seepage pit shall be ,5~t~ez:m~ned either by pemcolation tests conducCed in accordance with .¢ ?fanual of Septic Tank Practices or by the charactem of the soil ...... a on the values given in the following table: EFFECTIVE ABSORPTION AREA PER BEDROOM CHARA__~C. TER OF SOIL OR PER 100 GALLON DAILY SE~.!AGE FLOW Clean Coarse Sand or Gravel ''" 70 Clean Fine Sand 90 Silty S~n~ ~ ~ravel Clay with Considerable Sand or Gravel 120 150 Clay with Small Amount of Sand or Gravel 250 Where percolation tests are performed, they must be accomplished in accordance with the Manual of Septic Tank. Practices, PHS~ Pub. No.-525i. It is important that the capacity of the seepage pit be ~oraputed on basis of percolation tests made in each vertical stratum penetrated. The weir]ted average of the ~esults'~ould be computed to obtain the de- sign figure, :. Where seepage pits ape f6 be installed (which is the case 98% of the t~me) the soils log or percolation test must show the soils percolation characteristics of the effective seepage area between the inlet of the pit and the bottom of the pit. Sufficient nvestlgatlon must be accomplished to insure that the g~ound water table is at least two feet below the seepage pit excavation, Sell characteristics or percolation tests must be submitted on forws supplied by the Health Department om forms carrying the same information as those supplied by the Department. The completed forms must be certified by a registered professional eng~- neer, sanitarian, geologist or by such other p~ofesslonal persons who can show proof of sufficient knowledge of soil charactemistics through academic and field experience. . PHONE 272-34ZS November 2, 1971 Tryck, Nyman & Hayes 740 "I" Street Anchorage, Alaska 99501 ATTENTION: Dan Chapman Wo SUBJECT: Talus West Subd./Test Holes 12, 13 12134 Gentlemen: On October 29, two additional test pits were excavated at Talus West - 12 & 13, as shown on the revised location sketch, Figure A. Materials generally are silty sands (SM/250 sq.ft./BR) and sandy silts (ML/275 sq.ft./BR). No wa%er table is indicated. Grab samples were visually classified. SinceMely, ALASKA TESTLAB J~es L. Sch~ffel '- S/;aff Engineer ncs. JLS:ld C, LASKA TESTLAB CONSULTATION 0 TESTING ~ EXPLORATION {) CHEMICAL · MATERIALS ~ INSPECTION SOIL CLASSIFICATION CHART' $0% GRAVEL 0 I0 20 30 40 50 60 70 80 90 I00 GRAVEL (+~IOSCRE'EN) % ,BY WEIGHT NONFROBT SUSCEPTIBLE SOILS ARE INORGANIC SOILS CONTAINING LESS THAN :~°/o FINER THAN O. OZmm. GROUPS OF FROST-SUSCEPTIBLE SOILS: FI GRAVELLY SOILS CONTAINING BETWEEN ;5 AND 20% FINER THAN O.02mm. F2 BANDY SOILS CONTAINING BETWEEN 3 AND 15°/o FINER THAN O.02mm. a., GRAVEL~.Y SOILS CONTAINING MORi= THAN 20% FINER THAN O.02mm. AND SANDY SOILS (EXCEPT FINE SILTY, SANDS) CONTAINING MORE THAN 15% FINER THAN O.02mm. 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% FINER THAN O.OZmmo C. LEAN CLAYS WITH PLASTICITY INDEXES OF LESS THAN d. VARVED CLAYS. TEST HOLE LOGS ,SOIL DESCRIPTIONS The soil descriptions shown on the logs are the best estimate of the soil characteristics 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 "Sc-il 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"). Density - 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 (PI~ 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 predomi- nately 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 idenHflcation of these soils as a combination ball drop, and rolled thread test in which a 2" diameter ball of the Sand-Silt-Clay fraction is dropped 2' until a I" thick pat develops. The diameter of a 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 indicates clays and low silts. .Water Table - the apparent water, table at the time of observation. @ften the actual water table may be higher unless the hole Is allowed tc remain open or is oonverted to an observation well. Capillary Fringe - change from moist to very damp, or saturated soil, usually indicates that water table Is close. Peat - Fibrous material of macroscopic and microscopic fragments of decayed vegetable matter; very compressible, unsuitable for foundation or embankment. Color light brown to black. Ae - The upper layer, surface soil or topsoil, containing humus and/or organic debris, not satisfactory for foundations. ALASKA TESTLAB CLIENT TN&H PROJECTTalus West Subd. SHEET OF DATE. 29 October 1971 W.O. NO.. 12134 T.H. ~/ 12 ELEV.. Frost 6" F-4, Brown, Peat, Damp, PT F-4, Brown/Grey, Sandy Silt~-Some,Gravel~ DrY, Occasional Cobbles @ 5.0', ML ' Grab Sample F-4, Brown,:Gravelly Silty Sand, Dry, Some~Cobbles & Occasional Boulders ~ 8.0', SM L~"'~ __ Grab Sample __ F-3, Brown, Gravelly Sandy Silt, Dry, Occasional -- Cobbles, ML ~7~-~ -- Grab Sample Bottom Of Hole 13.5' --' CLIENT TN&H PROJECT Talus West Subd. T.H. ~ 13 ELEV. SHEET OF DATE,, 29 October 1971 W.O. NO._ 12134 Frost 6" F-4, Brown, Peat, Damp, PT __ Grab Sample F-4, Brown, .Sandy Silt, Damp, Some Gravel, Occasional-- Cobbles, Max. Size 8", ML Grab Sample __ F-2, Brown, Silty Fi~e Sand~ Dry, Some Gravel, Few -- Cobbles & Boulders, ~,ax. Size 13"~ SM F-4, Brown, Gravelly Sandy Silt~ Dry, Few Cobbles -- & Boulders, Max. Size 14", ML Grab Sample Bottom Of Hole 13.5'