Loading...
1977-SOIL REPORT GEOTECHNICAL ENGINEERING CORPORATION 1925 Oakcrest Avenue Roseville, Minnesota 55113 (612) 636-7744 220 - 20th Avenue North St. Cloud, Minnesota 56301 (612) 253-3451 V� RESULTS OF EXCAVATION INSPECTIONS AND DENSITY TEST � OL RESULTS V AT INNSBRUCK VILLAGE a �� ROJECT: REPORTED TO: v UNv INNSBRUCK VILLAGE SUBDIVISION DARRELL FARR DEVELOPMENT CORP. FRIDLEY, MINNESOTA 7286 NORTH 72ND LANE MINNEAPOLIS, MINNESOTA 55428 cc: DeWAYNE C. OLSON 7101 NE HIGHWAY 65 MINNEAPOLIS, MIINTNESOTA 55432 GEC JOB NO: 1247 DATE: JULY 7, 1977 F.H.A. SUBDIVISION NO: 3415 SUMMARY AND REMARKS BUILDING AREA 1. Organic swamp deposits were satisfactorily removed from below building areas. Anadequate oversize was achieved in these excavations. 2. Subcut areas were refilled with suitable material: Density tests taken as fill was placed indicate the fill was compacted adequately to meet our recommendations (90% of standard Proctor for fill less than 5 ' thick, 95% of standard Proctor for fill between 5 ° and 10 ' in thickness, and 100% of standard Proctor for fills, greater than 101 ) . 3. Because of low "N" values, which are an indication of the strength and compressibility of the soil material 'underlying the swamp deposits, a surcharge shorld be placed above the final grade of building pads in the areas of Lot 17 - garages 3 and 4, Lot 18 - house 3 and garages 2 and 3, and Lot 21, all houses and garages. The actual amount of surcharge has not yet been determined. HYDROLOGY•SOIL AND FOUNDATION ENGINEERING•TEST BORINGS MATERIALS TESTING• PERCOLATION TESTING• ENGINEERING GEOLOGY 9 CONSTRUCTION INSPECTION GEC #1247 - Page 2 4. Because of lack of fill material_, Lots 18, 21, and 22 have not been brought to their final grades. Density tests should be done as fill is placed in these areas and final grades are achieved. A surcharge should then be placed c ed in the areas listed above. STREETS AND DRIVEWAYS 1. Swamp deposits were satisfactorily removed. In the majority of cases, we were present to witness adequate oversize of the roadway excavation; therefore, we assume adequate oversize has been attained throughout the street areas. 2. The surcharge placed on West Bavarian Pass in the area of the swamp deposits subcut was placed during the second week of February, 1977. The surcharge r.eamined in place until at least April 26, 1977, at which time we concluded future settlement of the street would be within tolerable limits. Settlement pins placed over the surcharge area were monitored while the surcharge was in place. INTRODUCTION The referenced project site is located in southeastern Fridley north of North Innsbruck Drive. The proposed road, West Bavarian Pass will connect North . Innsbruck' Drive and Arthur Street. A total of 23 multifamily units are proposed in the subdivision. SOIL BORINGS Sixteen soil borings had previously been done at the project site. The results of the borings were reported in GEC Report #1.165. (Ten initial borings were reported in GEC Report #1117 ; six additional borings were drilled in October, 1976 and were reported witlthe initial 10 borings in GEC Report #1165 dated November 1, 1976. ) Borings done in low lying areas generally GEC GEC #1247 - Page 3 encountered, from the top down, swamp deposit, slope wash and/or fine alluvium, and glacial till. Borings done in upland areas indicated a layer of topsoil underlain by coarse alluvium and/or glacial till. SITE CONDITIONS The project site was quite heavily wooded prior to the start of earthmoving operations. Two definite swamp areas were present and a small low lying depression existed in the southern area of Lot 6. Multi-unit townhouses and single family houses surround much of the subdivision. RESULTS OF TESTING DONE IN WEST BAVARIAN PASS AND TRAPP COURT Excavation was begun in early February, 1977. At a meeting held 'on February 4, 1977, representatives of Farr Development Corp. , peWayne C. Olson, Alexander Construction, and Geotechnical Engineering were present to determine the course of action to be taken with regard to earthwork at the site. Our recommendations, previously reported in GEC Report No. 1165, listed three alternative methods of dealing with the earthwork situation in the area of the road- ways. These three alternatives included: (1) removing all compressible soils and replacing them with compacted fill; (2 ) removing swamp deposits, placing fill to grade, place a 3 ' sur?.- charge ur-charge 6n roadway and leave there for a period of two to four months (3) place fill directly on swamp deposits and apply a surcharge. The third alternative would have required the sur- charge to remain on for a longer period of time or to place a larger surcharge. The plan adopted was to remove the swamp deposits, place fill. to grade, and apply a surcharge. After the surcharge was placed, we installed settlement pins and monitored the settlement. We used the settlement information in determining when the surcharge could be removed. GEC GEC #1247 - Page 4 Density tests were taken in the fill placed in the roadways. 71he excavation and filling was done in February, 1977. The material, as placed, appeared quite dry. Cold. temperatures prevailed through much of the time excavation and filling was in progress. Also, no effort was made to place the fill in thin. lifts and compact it as the lifts were placed-, rather, the material was placed in four to five foot lifts and then traveled over with a front end loader and bulldozer. The density tests were done using the Density of Soil in Place by the Sand-Cone Method procedure outlined by ASTM D 1556-64 ( -#4 sieve basis) . The results of the density tests were compared to the Standard Proctor Density (Moisture-Density Relationship of Soils using a 5.5 lb RanLriier and 12 inch Drop) ASTM D 698-70 ( - #4 sieve basis) . The results of the density tests are as follows: TEST. ELEVATION PROC. No. * . NO., DATE LOCATION OR DEPTH (MIN/MIN) M,C. DENSITY 1. 2/4 West Bavarian 6 + 15 954 1 14.0 752 2 2/4 West Bavarian 6 + 15 9551j, 1 13.1 77 3 2/4 West Bavarian 5 + 50 956 1 9.9 85;2- 4 2/9 West Bavarian 2 + 80 950 1 11.6 7612- 5 2/9 West Bavarian 2 + 80 952 1 10.3 85� 6 2/9 West Bavarian 3 4- 25 9511-Z 1 11.3 7V2- 7 2/10 West Bavarian 4 + 90 956-3/4 1 10.0 87 8 2/10 West Bavarian 2 + 90 954-1-2 1, 13.1 762 9 2/10 WesL Bavarian 2 + 90 957 .1. 13.4 86 NOTE: The results of the Proctor are reported later in the report . FIELD SETTLEMENT READINGS AND ANALYSIS OF STREET EXCAVATION Settlement pins 'were installed in the surcharged area of West Bavarian Pass. The approximate locations of the pins are listed below. Originally, pins 1-11 were placed. A number of these pins were buried by the earthwork contractor and, therefore, additonal pins, A-F, were placed at a later date. However, after the ground had thawed, all the pins were found with the aid of a GEC GEC #1247 - Page 5 metal detector. Settlement pins consist of metal pins driven into the ground to a depth of about two feet. Readings were taken with a surveyors level and referenced to temporary bench marks established on two trees at the site. To cross check against possible error, readings of stations 5, 6, and A were cross checked using two bench marks. PIN STATION' 1 1 + 39.5 2 2 + 22 3 2 + 10-2.5 4 2 + 91 5 3 + 14 A 4 + 35 6 4 + 39 7 4 + 63 B 4 + 78 8 4 + 87 C 5 + 16 9 5 + 36 D 5 + 57 10 5 + 84 E 5 + 90 6 + 18 6 + 30 Plots of settlement versus t;he logarithm of time at various stations are attached. Pins were not placed in the street subcut of Trapp Court. This material was excavated at a later date and adequate compaction of refill material was achieved. Pins 1., 2, and 3 were placed on or near natural under-lying material (clacia- 1 till) . Very little settlement was witnessed at pins I-$ 2 and 3. Pin 1 appeared bent and driven over; therefore, it was not used in the settlement analysis. Pins 4 and 5 appeared to be GEC GEC #1247 - Page 6 located in the deeper area of the excavation, with the deepest subcut and therefore, the largest fill in the immediate area. Of these two pins, pin 4 appeared to exhibit the maximum settle- merit. This pin was therefore used to determine the maximum amount of settlement. Pin 7 was placed approximately over the center of the northern swamp, the settlement in this area did not appear to be of the same magnitude as that near pin 4. Our interpretation of the results indicate a maximum total settlement of 5" over a period of 20 years in the area of pin 4. A maximum differential settlement of less than 111 vertically to 10 feet laterally is anticipated. The above is based on data gathered with the surcharge in place. Removal of the surcharge wiil substantially decrease the amount of settlement. It is our conclusion that the surcharge served its purpose and the roadway area will satisfactorily support the proposed West Bavarian Pass and Trapp Court. However, as previously recommended in a telephone conversation with Mr. Jim London, adjustable screw-down gate valves and adjust-able rings beneath manhole covers should be installed to accommodate any settlement. RESULTS OF TESTING DONE IN HOUSI}, GARAGE, AND DRIVEWAY AREAS Initial earthwork in the areas of structures in Lots 17 , and 21 was done in February, 1977, at the same time as the excavation of West Bavarian Pass. At that time, we were riot called on to inspect excavations or do density tests of fill placed in building areas. Construction work was halted in late February because of inclement weather. Work was resumed in mid April, 1977. At this time, material underlying structures, garages, and driveways were to be excavated. We again were called on to inspect excavations to conduct density tests .on fill placed in su]cK--ut areas; this time on a full time basis. GEC GEC #1.247 - Page 7 Because we had previously not observed the excavation and refilling process in Lot 17 and 21, it was decided to do consolidation tests on representative samples of the material placed in these areas. In the laboratory, representative soil samples of material used at the site were compacted to different degrees of compaction and varying moisture contents. Consol- idation tests were done on these four samples. The results of one of the consolidation tests, the worst case condition, are given on an attached page. The results of the .load applied versus % strain are plotted. Based on the results of the consolidation tests, we, recormiended the removal and recompaction of fill placed previously in February, 1977. In addition to the results of the consolidation tests, inadequate oversize was was found in the excavated areas. Excavation and refilling proceeded from mid April through June 1977 at which time on-site borrow sources, needed to bring up the grades of lots 18, 21, and 22, were depleted. EXCAVATION INSPECTION Excavated areas were inspected by us. Based on the results of the excavation inspections, we feel all unsuitable material was removed prior to the placement of refill. DENSITY TESTS Density tests were taken in fill placed below structures and driveways. The results of the tests are attached. The field density tests were done using the Denszi.ty of Soil in Place by t -ie Sand - Cone Method procedure outlined by ASTM D 155E - 64 (- #4 sieve basis) . The results of the :field density tests were can pared to the Standard Proctor Density (Moisture Density Relations of Soils using a 5. 5 1b Rammer and 12 inch Drop) ASTM D 698-70 (- #4 sieve basis) . GEC GEC #1247 - Page 3 Based on the re,�ults of the tests, it is our opinion that suitable compaction was achieved. Areas that initially failed were recompacted and retested. REMARKS As previously mentioned, lots 18, 21, and 22 have not been filled to final. grade. Density tests should be taken while the remainder of fill to be placed is placed. As previously recommended, a surcharge should be placed in the area of lots 17, 18, and 21. Presently,we are doing density tests in backfill material placed in utility trenches. The results of these tests will be reported when the installation of utilities are completed. CLOSURE Report Prepared By: Under the Supervision Of: Charles W. Bisek Ifobert E. endergast, P.E. Minn. Reg. No. 8450 GEC l TIME (in days) 1 10 100 1000 0.1 '� W� w Pin 1* a H H w Pin 2 ul Pin 3 SETTLEMENT VERSUS TIME * Driven over and bent G J'T ALOWMEEMM CONMRATION TIME (in days) 1 10 100 1000 0.1 ' NNI Pin 4 Pin 5 F::::rt Fin 6 z w E-1 Pin 7 w Pin 8 Pin 9 Pin 10 in 11 SETTLEMENT VERSUS TIME TECHNICAL ENGWJEERNUO CORPORATUM TIME (in days) 1 10 100 1000 Pin A 0.1 ' Pin B Pin C Pin D Pin E Pin F w a SETTLEMENT VERSUS TIME ECHRWAL NG CO ATIM 0 .25 LOAD5 (tons per.square foot) 55 1 0 1*4 LOAD 2 4 .SAT URATE 6 �St.�rain 8 (, H 10 12 14 16 18 CONSOLIDATION TEST RESULTS Sample: Sandy clay, brown (CL) Atterburg Limits : LL = 30; PL = 16; PI = 14 DRY DENSITY MOISTURE CONTENT RELATIVE DENSITY INITIAL _'_"R 1.Zp'c F- 10.5%. 80% 109.8 Upc 0 26 / GEC #1247 DENSITY TEST SUMMARY -SHEET TEST APPROXIMATE PROCTOR MOISTURE RELATIVE NO. DATE LOCATION ELEVATION SAMPLE NO. CONTENT DENSITY REMARKS 1 4/19/77 Blk 6 850 1 / 4 8.1/18. 3 922 2 4/20/77 6 850 4 / 5 6/16 98 Retest #1 3 4/20/77 6 852 1 7 .8 1002 4 4/2j/77 6 854 1 9.1 912 5 4/22/77 6 8532 1 13. 3 10012 Retest #4 6 4/22/77 5 853 1 12.1 101 7 4/25/77 6 855 4 15.2 1002 8 4/25/77 8 964 4 17 . 3 95 9 4/25/77 5 56 4 8.8 992 10 4/26/77 8 66 3 13.6 102 11 4/26/77 6 57 4 14.2 96 12 4/26/77 5 and 6 57 4 12 .4 1002 Retest #11 .13 4/27/77 5 592 4 9.8 1001-2 14 4/27/7/ 6 58 1 10.9 100 15 4/27/77 5 612 1 8.2 102 16 4/27/77 6 61 A 11 .1 88 17 4/28/77 6 602 1 13.9 942 Retest #16 18 4/28/77 6 602 4 12 .1 85 Retest #16 & 17 19 4/28/77 6 60 4 10.4 95 Retest #16-18 20 4/28/77 6 60 1 8.7 100 Retest #16-19 21 4/28/77 6 6111 1 9.8 100 22 4/29/77 6 63 1 10.7 93 23 4/29/77 6 63 1 6.6 100 Retest #22 24 4/29/77 5 63 4 11.6 89 25 4/29/77 5 63 4 14.4 992 Retest #24 26 4/29/77 6 65 1 8.2 9812- 27 82-27 4/29/77 5 642 4 10. 5 95 28 4/29/77 6 66 4 10.9 94 29 5/2/77 14 54 5 7 .6 992 30 5/2/77 14 56 5 5.1 952 31 5/4/77 if3 67 1 20 912 32 5/4/77 " 14 58 3/4 4 8.5 77 33 5/4/77 If 17 59 1 13.6 103 34 5/4/77 if17 61 4 18. 5 94 35 5/5/77 6 66 1 9.4 1002 36 5/5/77 5 64 3/4 5 9.3 101 Retest #32 37 5/5/77 14 582 5 6.3 92 38 5/5/77 6 672 1 13.1 1042 39 5/6/77 if 6 682 1 14.3 101 40 5/6/77 11 17 55 4 13.6 96 41 5/6/77 if17' 5612 4 8.8 911-2 42 5/9/77 it17 52 5 13 .5 103 43 5/9/77 it 17 5311 1 11.7 99 44 5/9/77 It17 55 4 15.7 1002 Retest #40 45 5/9/77 17 57 4 14.9 1012 Retest #41 46 5/10/77 17 55 1 14.2 992 47 5/10/77 (B) 15 51 4 10 .8 782 48 5/11/77 15 52 5 7 .9 902 49 5/11/77 17 542 1 12 . 9 103 DENSITY TEST SUMMARY SHEET TEST APPROXIMATE PROCTOR MOISTURE RELATIVE NO. DATE LOCATION ELEVATION SAMPLE NO. CONTENTE DENSITY' REMARKS 50 5/11/77 Blk 15 52 1 12 .4 1012 Retest 47 & 48 51 5/11/77 17 552- 1 9.6 98 52 5/11/77- " 15 55 1 8.6 1012 53 5/11/77 15 572 5 8.7 104 54 5/12/77 17 57 4 16.4 992 55 5/12/77 15 60 1 6 .8 962 56 5/12/77 17 582 4 11.6 1012 57 5/12/77 21 and 22 53 1 13.1 1022 58 51/3177 17 59 4 11.0 932 59 5/13/77 17 59 4 10.1 92 60 5/13/77 17 59 1 8.3 98 Retest 58 & 59 61 5/16/77 17 and 18 602 4 16.3 100 62 5/17/77 17 and 18 62 5 10.4 101 63 5/17/77 8 53 4 13 .5 100 64 5/18/77 8 552 4 12 .0 96 65 5/18/77 3 and 4 522 4 13.0 1002 66 5/18/77 14 622 4 10.1 97 67 5/18/77 14 632 1 9.5 95 68 5/18/77 8 58 4 15.2 1032 69 5/19/77 3 and 4 54 3/4 4 11 .8 10012 70 5/19/77 16-18, 24 64 1 12 .4 100 71 5/19/77 " 18 62 4 12.1 95 72 5/19/77 " 2 662 5 11 98 73 5/19/77 " 3 and 4 57 4 11 .5 962 74 5/20/77 ' 3 and 4 57 4 14.1 10012 Retest #73 75 5/20/77 " 3 and 4 58 4 13.9 90 76 5/20/77 " 3 and 4 58 4 12 .7 90 77 5/20/77 " 3 and 4 58 4 13.4 982 Retest #75 & 7E 78 5/23/77 ' 17 652- 4 10.7 83 79 5/23/77 3 and 4 59 4 16.3 75 80 5/23/77 11 742 4 15.5 97 81 5/23/77 17 652 4 16 .8 882 Retest #78 82 5/24/77 " 11 77 4 12 .6 95 83 5/24/77 " 3 and 4 59 4 13.3 982 Retest #79 84 5/24/77 " 11 79 4 12.6 98 85 5/24/77 17 652 4 14.8 972- Retest #78 & 81 86 5/25/77 11 802- 4 12 .9 98 87 5/25/77 If 3 and 4 59 4 13.6 982 Retest #79 & 8-� 88 5/25/77 3 and 4 59 4 13.9 95 Retest #79, 83, 81 89 5/25/77 17, 16, 24 652- 4 12 .2 1022 Retest #78, 81, 8E 90 5/25/77 If 4 59 4 12.9 98 Retest #79, 83, 81 91 5/25/77 If 11 812 4 11.4 982 and 88 92 5/25/77 " 4 59 4 13.0 992 93 5/27/77 4 612 1 12 .1 102 94 5/27/77 17 69 1 11.1 1032 95 6/3/77 18 and 21 50 1 12. 3 102 96 6/6/77 18,21 (N.side) 52 1 11 103 97 If21, 24(S.side)52 98 1117 and 18 592 1 13.4 101 99 6/7/77 " 18, 21, 22 54 1 13.1 101 100 6/7/77 It 4 63 1 89 1022 r t DENSITY TEST SUMMARY SHEET TEST APPROXIMATE PROCTOR MOISTURE RELATIVE NO. DATE LOCATION ELEVATION SAMPLE NO. CONTENT DENSITY REMARKS 101 6/7/77 Blk 21 52 1 11.4 104.5 Retest #97 102 6/7/77 If21 54 4 17 .1 98 * *very moist, therefore leave dry until contractor returns to finish filling STANDARD PROCTOR ASTM D 698 PROCTOR SOIL OPTIMUM MOISTURE MAXMIUM NUMBER TYPE CONTENT, PER CENT DRY DENSITY 1 Sandy Clay, brown (CL) 13.0 118.4 3 Sandy Clay, brown (CL) 14.2 116.5 2 Clayey Sand, brown (CL) 14.6 114.2 4 Sandy Clay, brown (CL) 16 .0 114 5 Silty Sand, fine strained, 10.2 129.2 brown (slightly plastic to plastic-SM)