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5a. Soil report ITCO_13160 182nd StreetReport of Geotechnical Exploration 13160182. d Street North Scandia, Minnesota April 30, 2018 Allied Project 18012 ITCO Allied Engineering Company. 7125 West 126th Street, Suite 500 Savage, Minnesota 55378 Ph: 9.52-890-5909 Fax: 952-8905883 SUBGRADE EXPLORATION I 13160182ND STREET NORTH Scandia, Minnesota Allied Project No. 18012 April 30, 2018 INTRODUCTION This report presents the results of subgrade exploration performed by our firm for a proposed residence This work was requested by Mr. Jim Tonrey on January 18, 2018 and was authorized by the same on February 2, 2018. Our work was performed as described in our proposal for subgrade exploration dated January 18, 2018. PROJECT INFORMATION The project site is a residential lake lot located at 13160 182"d Street North, Scandia, Washington County, Minnesota. The existing cabin will be removed and a new residence constructed. BORING LOCATIONS AND ELEVATIONS The boring was located 26 feet from the NE corner of a hole on the property which may be the area inside a trapezoidal shaped area as shown on the site plan included in the appendix. The base of a power pole located at the NW property corner was used as a benchmark. The ground elevation at the boring location was based on the benchmark elevation. Elevations listed on the boring log are in relation to the benchmark FIELD EXPLORATION One Standard Penetration Test (SPT) boring was put down to a depth of 16 feet. The boring was put down in accordance with ASTM 1586-99: "Standard Method for Penetration Test and Split -Barrel Sampling of Soils". Using this procedure, a 2" Q.D. split barrel sampler is driven into the soil by a 140-1b weight falling a distance of 30 inches. After an initial set of 6", the number of blows required to drive the sampler an additional 12 inches is known as the standard penetration resistance or N - value. The N -value provides an indication of the relative density of cohesionless (coarse grained) soils or of the consistency of cohesive (fine-grained) soils. As the samples were obtained in the field, they were visually and manually classified. Representative portions of the samples were then sealed in clean glass soil jars and returned to the laboratory for further examination and verification of the field classification. The recovered soil samples were classified in accordance with the Unified Soil Classification System, ASTM D: 2488-00. A chart illustrating this classification method is included in the appendix to this report. Logs of the test borings indicating the depth and identification of the various strata, measured penetration resistances, soil classifications and the results of water level checks are included in the appendix to this report. SUBSURFACE CONDITIONS Boring BY -I Boring B-1 consisted of 7 inches of wet topsoil, underlain by wet sandy clay with. ' some gravel to 2.5 feet of depth, sandy clay to 7.5 feet of depth, sandy clay with some gravel to 12.5 feet of depth, moist sandy clay with a rock to 12.9 feet of depth, sandy clay from at least 14.5 feet to 14.7 feet of depth, and fine sand with some gravel to 16 feet of depth. N -values ranged from 33 to 77, indicating that the soils were all hard in consistency. There was also an N -value of 50+ which means that the sampler didn't advance at least 6 inches after 50 blows and this most likely was due to a rock below the sampler. N -values below 6 are considered low for residential structures. There were no N -values below 6. 2 Groundwater was not encountered in the boring. Groundwater conditions may vary both seasonally and annually based on precipitation amounts, patterns, and both surface and subsurface drainage in the local area. Included in the appendix to this report are logs of the test borings, which describe the conditions, encountered at each drilling location. The depth of the individual strata of soil may vary at and between the drilling locations due to unsampled intervals, the occurrence of transitions between. soil layers and the natural variability of the subsurface conditions. CONCLUSIONS AND RECOMMENDATIONS . Organic topsoil, peat, organic soils, and any soft soil layers, which may be encountered, should not be relied upon for support of the proposed residential footings, slabs or. controlled fills that will support these elements. These materials should be removed and replaced below the proposed structure. A qualified soil technician should examine the excavated areas before suitable fill material is placed. ITCO Allied Engineering Co. can provide this service during construction. It should be possible to provide support for the planned structure with a conventional spread footing foundation system. If unsuitable soils are encountered, these can be corrected by using excavation and controlled refilling procedures together with an observational approach. This would require excavation in order to prepare for the placement of controlled fill to make grade for concrete for footings or slabs. The non -root infested and inorganic on-site soils would generally be suitable for reuse as controlled and compacted fill material. The topsoil or other materials, which would not be suitable for use as controlled fill, may be able to be used as surface fill in the lawn and landscaping areas. Additional recommendations are presented in the following sections. The Department of Housing & Urban Development (D -HUD), which underwrites F.H.A. mortgages, requires a separation of 4.0 feet between the highest observed groundwater elevation and the lowest basement slab. Although this. may or may not be a requirement in Scandia, the city should be contacted to determine their requirements. 3 1. EXCAVATION In general, grubbing and stripping operations should remove all significantly organic or root infested soils from the areas to be worked..Frozen material, soft consistency clays or otherwise unsuitable soil and debris should be removed. Where undocumented fill or otherwise unsuitable soils are exposed in the base of excavations, which will support slabs, pavements or footings, these materials should also be removed. Frozen sails resulting from frost penetration may turn soft upon thawing and would need to be removed. For the support of fill sequences, slabs, or footings it will be important to remove unsuitable soils prior to the placement of the controlled and compacted fill to make grade for concrete foundations and slabs. Once the organic topsoil layers and otherwise unsuitable materials have been removed, the completed excavations should be observed by an experienced soil engineer or technician and the conditions judged to be suitable prior to the placement of controlled and compacted fill to make grade for concrete footings or slabs. 2. FOUNDATIONS It should be possible to provide support for spread footing foundations systems using excavation and controlled filling procedures. As mentioned previously, the topsoil, peat, organic silt, organic clay, soft clay, and any uncontrolled fill encountered during the excavation work should not be relied upon for support of footings, slabs or controlled fills which will support these elements. It will be important to monitor the conditions exposed in the excavations during the grading work prior to the placement of fill to make grade for concrete for footings or slabs. Hand auger borings and Dynamic Cone Penetrometer (DCP) tests should be done in the completed excavations and the exposed conditions judged suitable by an experienced soil engineer or technician prior to the placement of footings or fill.ITCO Allied Engineering Co. is capable of and available to do this work. Once the recommendations presented in this report have been implemented, a net allowable bearing pressure of 2000 pounds per square foot may be utilized for the proportioning of individual footings. In designing the footings, it is recommended that they be designed to exert approximately equal pressures to the bearing strata. This should limit total and differential settlements to V and Y? respectively. 4 For frost protection, we recommend that footings in unheated areas be placed at a depth of 48 inches below finished grade. For decks and porches it is recommended that this be increased to 60 inches if the soil is frost susceptible. In heated portions of the buildings where frost susceptible materials are absent, a depth of 42 inches would be adequate. Where full or partial basements are utilized, frost depths for garage areas and porch structures should be maintained as outlined above. 3. FILL PLACEMENT In the event that unsuitable soils are encountered and need to be replaced, the fill material should be mineral soil, preferably granular, and free of debris, boulders and organic material. The non=organic on-site soils would be suitable for reuse as controlled fill material provided that they are dry enough to meet compaction requirements. It may be difficult to dry wet soils sufficiently and it may be necessary to replace some of this material with off site material. Fill should be placed and compacted in a manner that will allow complete compaction. of the entire fill layer to a minimum of 95% of the Standard Proctor Density according to ASTM D: 698 in the building pad area. Required compaction should be increased to 98% below all footings. For roadway construction, the top 3 feet of roadway subgrade should be compacted to 100%. A minimum of one representative field density test should be performed for each two feet of fill placed at a time in a given work area. Density tests in mass fill areas should be performed at a rate judged sufficient to represent the fill sequence as a whole. Where sand fills are to be compacted, smooth "drum" type vibratory equipment would be preferred, however, a sheepsfoot roller with short wide pads may provide adequate compaction. Fill areas should be properly oversized to provide for adequate distribution of the imposed loads. The fill supporting structural elements should extend at least one foot horizontally beyond the structure, slab or edge of the footing. Fill surfaces should extend downward and outward on a 1:1 slope to competent soil. If the fill slope is unconfined by other soils, the downward and- outward slope should be flattened and stabilized. Also, no unremedied excavations should be carried out within the fill oversize areas. 5 4. FOUNDATION DRAINAGE Although groundwater wasn't found in the boring, groundwater elevations can fluctuate throughout the year, so foundation drains should still be considered if a below grade slab is included. Also, some communities require that foundation drains be installed regardless of site conditions. The City of Scandia should be contacted to determine their requirements. If included, the recommendations in the next paragraph should be followed for installing the foundation drains. In planning backfill zone drain tile installation, the invert elevation should be below the level of the lowest floor slab. The drain line should be adequately protected from blockage prior to backfilling by a suitable encapsulation of gravel, (such as Mn/Dot spec 3149.2 H; "coarse filter aggregate"), and geotextile separation fabric. In the backfill zones above the drain tile the use of granular material is recommended. Sand for this purpose should contain less than 12% passing the number 200 sieve, (WDot "select granular borrow"; spec 3149.2 B). Care should be taken during the backfilling operations to ensure that the drainage materials are not crushed or deformed. Fill installation in these areas should be initiated with a two -foot lift of the granular backfill. A two to three foot thick compacted clay cap, with a positive slope away from the structure, may be placed at the top of the backfill zone to aid in reducing the infiltration of groundwater into this area which would need to be carried by the drain the system. It should be noted that the construction of the backfill zone drainage system should be performed with the same level of care as the foundation wall itself. 5. FINAL SITE TOPOGRAPHY The final soil surfaces should be graded to provide adequate drainage away from structures and pavements in order to minimize deleterious effects associated with water infiltration. The areas adjacent to footing walls should be adequately compacted (not loosely placed) and provided with drainage outlets to avoid this zone acting as a "sump" and creating nuisance water conditions. Compliance with the building code provision for positive surface drainage away from the structure should also aid in reducing the quantity of infiltration into the backfill zones adjacent to foundation walls. C$I STANDARD OF CARE The recommendations contained in this report are professional opinions. These opinions were arrived at in accordance with generally accepted ' engineering practices currently in use at this time, location and for projects of this type. Other than this, no warranty is implied or intended. Soil samples recovered from the test borings will be retained in our offices for a period of thirty days from the date of this report. After that time they will be discarded unless prior written instructions to the contrary are received. I hereby certify that this report and/or specification has been prepared by me or under my direct supervision and that I am a duly registered Professional Engineer under the laws of the State of Minnesota. If you have any further questions or we can be of any further assistance, please do not hesitate to phone or write. ITCO ALLIED ENGINEERING COMPANY Robert Sullentrop, P.E. Minnesota Registration No. 17823 7 APPENDIX A Boring Location Flan I< OP )ND .I" BWLQLNC N PIPe CORNER 5 ,-!r_OE— off W. OF LINE --WT–QN� I MAI MAY A?FLY. DENOTES SLOPES CREAM THM 78 �Y WnIN THE BUILDINC 5 ETBAex ARE, �LI'q r QED LIDAR CONTOURS. NOT F t q MOTES SLOPES BETWEEN 12% AND 4?g3 Isa WrMN TWE SUILDING SEMCx 9p F EW AEA Wm ON UOAR CONTOURS,Ro bo' ��4 A� �� "'c I 0 `O 1 Ir ` � tee..\___.,-�"•� A 0.3' W:`9F� LOT LINS ZfffiMw j m N � ® � 0 SET 1[2- IRON PIP, MARKED RAS NO,: Ai CABLE TV PE€1E57, CaNTE OP PA - ELECTRIC PEDESTF € IRSMx:.TRANSR y '�`–FOUNP ANCLE x. DU B-1 OU OU rolift �+ OVERHE M N 'V7 11"E e.__ SOUTH LNE e SEC. 3,.{2,00.00 PLAT)32, *43 ie/ SURVEY (VOTES: TNG LEGAL DESCRIPTION: 1. BEARINGS ARE BASED ON COORDINATES SUPPLIED BY THE WASHINGTON COUNTY SURVEYORS OFFICE_. )WN ON Quit Claim Deed DOC. NO. 3391342) NAD 88 2. UNDERGROUND UTILITIES NOT SHOWN OR LOCATED. 6750 Stillwa LEGEND: ® FOUNOMONUMEN 0 SET 1[2- IRON PIP, MARKED RAS NO,: CABLE TV PE€1E57, ® - ELECTRIC PEDESTF Ei IRSMx:.TRANSR GUY WRE -0 POWER POLE ® TELEPHONEPEDES_ FLARED END SECT STORM MANHOLE �+ OVERHE M N 'V7 11"E e.__ SOUTH LNE e SEC. 3,.{2,00.00 PLAT)32, *43 ie/ SURVEY (VOTES: TNG LEGAL DESCRIPTION: 1. BEARINGS ARE BASED ON COORDINATES SUPPLIED BY THE WASHINGTON COUNTY SURVEYORS OFFICE_. )WN ON Quit Claim Deed DOC. NO. 3391342) NAD 88 2. UNDERGROUND UTILITIES NOT SHOWN OR LOCATED. 6750 Stillwa APPENDIX B Poring Logs ITCO ALLIED ENGINEERING CO, LOG OF BORING B-1 Sheet 1 of 1 Project: 13160 182nd Street North DRILLER Mike TFCHN;CIAN Tom BORING NO. 1 LOCATION B-1 DRY ON COMPLETION ? yes DATE April 26, 2018 SURFACE ELEV, 985.9 FT. WATER LEVEL DATA (IF APPLICABLE) REFUSAL: No DEPTH FT. ELEV. FT. DRILLING: DEPTH Fr. SAMPLED 16.0 FT. 4.9 M ELEV. FT, BORING TIME: 2:00 PM After 2 Hours DEPTH FT. ELEV. FT. BOTTOM OF HOLE DEPTH 14.5 FT. ELEV. 971.4 FT. Cave-in DEPTH FT, BORING ADVANCED BY: POWER AUGERING X STRATUM DEPTH SAMPLE DEPTH SAMPLE NUMBER SAMPLE TYPE FIELD RESULTS LABORATORY RESULTS STRATUM DESCRIPTION FROM TO FT: ELEV. FT. FT, N-Value Op LL PI %M 0.0 - 985.9 7" Mst Dk Brn Snd Clayev Topsoil Wet Brown Sandy Clay - 0.0 2.0 1 Grab WlSome Gravel, CL 2.5 - 983.4 2.5 4.0 2 SS 40 Reddish Brown Sandy Clay, CL -- 5.0 - 980.9 5.0. 6.5 3 S5 52 Red Sandy Clay, CL - 7.5 ' - 978.4 7.5 9.0 4 SS 55 Red Sandy Clay WlSome Gravel, CL - 10.0 --- 975.9 10.0 11.5 5 SS 77 . 12.5 - 973.4 - 12.5 12.9 6 SS 50+ - 5" Moist Reddish Brown Sandy Clay Wla Rock CL 14.5 - 971.4 14.5 16.0 7 SS 33 2" Reddish Bm Sand Cla , CL - - Light Brown Fine Sand - WlSome Gravel, SP REMARKS: An N-value of 50+ means that the sampler didn't advance 6" after 50 blows.,and was likely due to the sampler on a rock. APPENDIX C Soil Classification System ALLIED TEST DRILLING COMPANY SOLL CLASSIFICATION SYSTEMS Unified Soil Classif cation System ASTM: D 2488-84 Major Divisions Group Symbol Typical Group Names GRAVELS Clean gravels GW Well -graded gravels, Well -grade gravel with sand' A-1 <5%passing No. A-2 A-4 A-5 More than 50% 200 sieve GP Poorly -graded gravel, Poorly -graded gravel with sand` COARSE- GRAINED SOILSfraction Granular soils of coarse retained on Na. 4 sieve A-2-6 A-2-7 Sieve Analysis: Gravel with fines > 12% passing No. 200 sieve GM Silty. gravel, Silty gravel with sand' GC Clayey gravel, Clayey gravel with sand' SANDS 50% or more of Clean sands <, 5% passing No. 200 sieve SW Well -graded sand, Well -graded sand with gravel' _-- More than 50% retained on the No. SP Poorly -graded sand, Poorly graded sand with gravels 200 sieve coarse fraction passes No. 4 Sand with fines SM Silty sand, Silty sand with.gravel2 Sieve >12% passing No. 200 sieve SC Clayey sand, Clayey sand with gravel' FINE-GRAINED SII.TS AND CLAYS 11IL, Silt, ,Silt tvith sand'. Sandy silt`' _ CL — — — Lean clay. Lean clay with sand', Sandy lean clay' SOILS Liquid litnit less than 50 OL Organic silt, Organic clay Cohesive soils � SILTS AND CLAYS MH ...-.�.�...�.µ�� Elastic silt, Elastic silt with sand', Sandy elastic silt'' � 50°!° at' more CH Fat clay, Pat clay with sand' passes the No. 200 sieve Liquid limit more than 50 35 max 35 max 36 mitt 36 min ON Organic clay. Organic silt — HIGHLY ORGANIC SOMS PT s Peat Boundary classifications are designated by dual group symbols. For example, (SP -SM) for Poorly -graded sand with silt. 'More than15'%, sand '-More than 15% gravel '15% to 30% retained on No. 200 sieve '30% retained on No. 200 sieve AASHTO Sail Classification System W Granular Materials Silt -Clay Materials (35% or less passing No. 200 sieve) , (>35% passing No. 200 sieve) A-1 A-.1 A-2 A-4 A-5 A-6 A-7 A-8 A -1-a A -I -b A-2-4 A-2-5 A-2-6 A-2-7 Sieve Analysis: Percent Passing No, 10 50 max No. 40 30 coax 50 max 51. min No..200 15 max 25 max 10 mdx 35 tnax 35 max 35 max 35 max 36 mitt 36 min 36 min 36 min Characteristics of Fraction Passing No. 40: Liquid limit 40 max 41 min 40 max 41 thin 40 max 41 min 40 max 41 min Plastic gvAt I w A.. � 6 max NP 10 max 10 max 1 I zein .l 1 min 10 max 10 max 11. min 11 min seal Types of stone fragments fine Peat, highly i nlficant Constituents ravel and sand sand Silty or clayey gravel and sand silty soils clayey soils organic soils eneral Sub.gradeAgLingl Excellent to good Fair to oornsatisfacton