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Home My WebLink About4222; Palomar Airport Road Widening; Palomar Airport Road; 1986-12-01GEOTECHNICAL AND PAVEMENT ANALYSIS PALOMAR AIRPORT ROAD WIDENING CARLSBAD, CALIFORNIA FOR WILDAN ASSOCIATES 6363 GREENWICH DRIVE, SUITE 250 SAN DIEGO, CALIFORNIA 92122 JOB NO. 4222 DECEMBER 1, 1986 Testing Engineers — San Diego Mailing Address: Post Office Box 80985 San Diego, CA 92138 3467 Kurtz Street San Diego, CA 92110 (619) 225-9641 December 1, 1986 Job No. 4222-1 Wildan Associates 6363 Greenwich Drive, Suite 250 San Diego, California 92122 Attention:Mr. Mike Sabvini Subject:Geotechnical and Pavement Analysis Palomar Airport Road Widening Carlsbad, California Gentlemen: The results of our geotechnical and pavement analysis are presented in this report. The accompanying report presents conclusions and recommendations pertaining to the site, as well as the results of our field reconnaissance and laboratory results. Palomar Airport Road Widening Carlsbad, California December 1, 1986 Job No. 4222-1 We have appreciated the opportunity to be of service to you on this interesting project and look forward to a continued association on this and future projects. If you have any questions, please do not hesitate to contact our office. Vincent J. Patula Project Geologist VJP/SMP/DM/eh Addressee (4) Respectfully submitted, TESTING-KNGINEERS-SAN DIEGO Materials Engineer Stephen M. Poole, RCE 40219 Geotechnical Department Manager TABLE OF CONTENTS Page INTRODUCTION 1 PROJECT DESCRIPTION 1 PROJECT SCOPE 2 FIELD EXPLORATION 2 GEOLOGIC HAZARDS 3 SLUMPING 3 LABORATORY TESTING 5 CLASSIFICATION 5 MOISTURE/CONTENT 5 U.B.C. SWELL TEST 7 "R" VALUE 8 CONCLUSIONS AND RECOMMENDATIONS 9 RECOMMENDED GRADING SPECIFICATIONS 10 GENERAL DESCRIPTION 10 PREPARING AREAS TO BE FILLED 11 MATERIALS 13 PLACING, SPREADING, AND COMPACTING FILL MATERIALS ... 15 INSPECTION 16 SLOPES 17 PAVEMENT SECTION 17 LIMITATIONS AND UNIFORMITY OF CONDITIONS 21 ENCLOSURES; Sample Location Map Figure 1 Unified Soil Classification Plate 1 City of Carlsbad Design Table Plate 2 INTRODUCTION PROJECT DESCRIPTION A major portion of the site is located between McClellan Drive and El Camino Real on the north and south sides of Palomar Airport Road see Figures 1,2, and 3. The road widening extends from 550 feet west of McClellan Drive to 100 feet east of El Camino Real. It is our understanding that the road widening is to be developed by additional grading and remedial slope stability measures. It is to be widened to its ultimate prime-arterial standards. To assist in the preparation of this report we were provided with a copy of the proposed improvements by Wilden and Associates. N\n~13"IDDlA! 3 I_k A •o O > CO 33 > ? m 0 r- H 0 30 >o i > 0 0 Z m 3; 5 ^z CO oz -I'sl S- 1?s c>G- m O Z 31 1 L-_ O O CO> 2TJr-rn r OO> H Z O a: w "£o£ TImm H "A \V\\\\\\V:A\\'\V,« \\W\Yl\ Z3 CO r-0 2 > 3) > 5 o 2"^ 3D O > O mX % Oz (0> 2 .•o r~ O > H 0 Z 2> U CO m g§ 8g m o Q C, z "n Hi z ** Wildan Associates . Page No. 2 Paloraar Airport Road December 1, 1986 Job No. 4222 PROJECT SCOPE This investigation consisted of surface reconnaissance, limited subsurface hand augering, obtaining representative disturbed samples, limited laboratory testing, analysis of field and laboratory, and preparing this report. Specifically the intent of this study is to: o recommend three structural pavement sections o give recommendations for cut and/or fill slopes required to extend the roadway shoulder o identify soils present and their properties o provide limits of the report which would result in recommendations over the project limits FIELD EXPLORATION Subsurface conditions were explored by hand augering to depths ranging from 1 to 5 feet in order to obtain bag samples for laboratory analysis and soil profile description. Sample locations are shown on Figures 1 through 3. Wildan Associates Page No. 3 Paloraar Airport Road December 1, 1986 Job No. 4222 GEOLOGIC HAZARDS SLUMPING In their present condition there is a potential for further surface slumping of the fill slopes adjacent to the proposed roadway widening and the slopes underlying the road bed. It is possible that this soil movement could cause minor road damage. The two major slope areas presented in Figure 1, Section B, and Figure 2, Section D, have undergone episodes of surficial slumping and soil creep. In Section D on the western side of the slope there is a visible slumping episode of approximately 72 feet long at the scarp. This section has a slope of 1.3 to 1 (horizontal to vertical) and is sparsely vegetated. Wildan Associates Page No. 4 Palomar Airport Road December 1, 1986 Job No. 4222 Further evidence that soil creep is occuring, is the presence of curved tree trunks. Although no present tension cracks were observed along the top of the slope, with further erosion the slump scarp, may with time, undermine the roadway and sidewalk. The slopes in Section B exhibit heavy rilling, 6 inches to 2 feet in depth, and several slumping episodes below and above the backset bench area were observed. One set of tension cracks measured was approximately 2 inches in width and 12 feet in length. In several different areas bulging of the toe of the slope was observed. The slumping events occured in areas that were sparsely landscaped and had slopes of 1.3 and 1.5 to 1 (horizontal to vertical). Other areas that are less than 2 to 1 and vegetated, exhibited rilling but no slumping events. Wildan Associates Page No. 5 Palomar Airport Road December 1, 1986 Job No. 4222 LABORATORY TESTING CLASSIFICATION Soils were visually classified according to the Unified Soil Classification System as presented on Plate 1. Percent material passing the No. 200 sieve was used as an aid in soil classification with the results and soil description presented on Table 1. MOISTURE/CONTENT For selected disturbed soil samples, field moisture contents were obtained by hand augering. The field moisture content was determined as a percentage of the dry weight. Results of these tests are shown on Table 1. Wildan Associates Palomar Airport Road Page No. 6 December 1, 1986 Job No. 4222 TABLE 1 Sample No. 1 2 Depth , Feet 0-3 0-1 Moisture Content, Percent 25.3 9.9 Percent Passing No. 200 -- Description dark brown sandy clay light brown silty fim 3 4 5 6 7 8 0-5 0-1 0-2 0-1 22.1 surface 6.6 surface 7.4 12.8 15.8 9.9 48 65 sand medium brown clayey fine sand gray brown silty fine sand, some iron staining medium brown clayey sand brown-yellow silty fine sand brown fine sandy clay brown silty sand, slightly clayey Wildan Associates Page No. 7 Palomar Airport Road December 1, 1986 Job No. 4222 U.B.C. SWELL TEST The expansion potential of selected samples was evaluated using a swell test (U.B.C. Test Standard No. 29-2). A sample of soil was molded to a saturation content of approximately 50 percent. A surcharge load of 144 pounds per square foot was applied to the sample, which was then inundated. The expansion index (E.I.) was recorded relative to the increase in the thickness of the soil sample to the original one inch sample. The sample was allowed to swell for at least 24 hours. Results were as follows: Test Pit Depth, Material Expansion Location Feet Type E.I. Potential 1.5 brown slightly 59 Medium sandy clay Wildan Associates Palomar Airport Road Page No. 8 December 1, 1986 Job No. 4222 "R" - VALUE Representative samples of near surface native soils were tested to evaluate pavement design criteria. These samples were taken from native subgrade below base materials at corehole locations indicated on Figures 1 and 3. Testing was done using the "R" - value test, California Standard 301. The results were as follows: Test Location 10 Depth Feet 1.0 1.2 Material Type clayey silty fine sand silty fine sand with trace clay "R" - Value 24 21 Wildan Associates Page No. 9 Paloraar Airport Road December 1, 1986 Job No. 4222 CONCLUSIONS AND RECOMMENDATIONS Based on our field investigation, laboratory analysis, and engineering analysis, we offer the following conclusions and recommendations: 1. Site materials consist of silty fine sands and sandy clays. These materials are adequate for the proposed roadway widening. 2. Remedial slope repair, landscaping and maintenance is recommended. 3. Additional exploration is recommended to determine depth to bedrock, soil stratigraphy, and their engineering properties. For the proposed widening of the roadway by filling, the engineering properties of the underlying soils must be determined in order to evaluate removal depths and other construction recommendations. 4. A review by a geotechnical engineer of the revised grading plans, to determine the drainage system necessary to accommodate runoff and aid in the slope stabilization is recommended. wildan Associates Page No. 10 Palomar Airport Road December 1, 1986 Job No. 4222 RECOMMENDED GRADING SPECIFICATIONS 1. GENERAL DESCRIPTION 1.1 These specifications have been prepared for general grading and site development of the project. Testing Engineers-San Diego, herein after, described as the Soil Engineer, should be consulted prior to any site work connected with site development to ensure compliance with these specifications. These specifications shall be used in conjunction with the soil report of which they are a part. 1.2 This item shall include all site work consisting of all clearing and grubbing, preparation of land to be filled, filling of the land, spreading, compaction, density testing of the fill, and all subsidiary work necessary to complete the grading of the filled areas to conform with the lines, grades, and slopes as shown and specified on the accepted plans. Wildan Associates . Page No. 11 Palomar Airport Road December 1, 1986 Job No. 4222 1.3 The Soil Engineer shall be the Owner's representative to inspect the construction of fills. Excavation and placing of fill shall be under the direct inspection of the Soil Engineer. In the event that any unusual conditions, not covered by these specifications are encountered during grading operations, the Soil Engineer shall be immediately notified. 2. PREPARING AREAS TO BE FILLED 2.1 All existing unnecessary materials such as timber, logs, trees, brush, abandoned buildings, debris and other rubbish shall be removed or disposed of so as the area will be left neat and with finished appearance. 2.2 All loose soil and organic matter shall be removed from the surface upon which the fill is to be placed. The surface shall then be plowed or scarified to the recommended depth, and until the surface is free from ruts, hummocks or other uneven features which would tend to prevent uniform compaction by the equipment to be used. Wildan Associates Page No. 12 Palomar Airport Road December 1, 1986 Job No. 4222 2.3 The area, after being cleared should be disced or bladed until it is uniform and free from large clods. Proper moisture content must be maintained. The moisture content should be at least within two percent of optimum moisture by adding water or aerating and compacted to a relative compaction of not less than 90 percent of the maximum dry density as determined by ASTM Test Procedure No. D-1557. 2.4 Buried tanks, if encountered, should be removed and the resulting depressions properly backfilled and compacted. The soil surrounding the buried tanks should be tested for hazardous materials and disposed of properly. Wildan Associates Page No. 13 Palomar Airport Road December 1, 1986 Job No. 4222 3. MATERIALS 3.1 Materials for compacted fill shall consist of any material imported or excavated from the cut areas that, in the opinion of the Soil Engineer, is suitable for use in constructing fills. The materials used should be free of organic matter and other deleterious substances. It shall contain no rocks or hard lumps greater than 6-inches in size. 3.2 No materials of a perishable, spongy or improper nature shall be used in filling. 3.3 Any potentially expansive soil encountered shall be used as fill only below 3 feet of the design finished grades. The upper 3 feet of fill shall be comprised of non-expansive sandy fill material. Any expansive soil encountered at the finished subgrade elevations in cut Wildan Associates Page No. 14 Palomar Airport Road December 1, 1986 Job No. 4222 areas shall be undercut and replaced with compacted non-expansive sandy fill material. The depths and lateral extent of any required expansive soil removal shall be determined by the Soil Engineer at the time of construction. 3.4 The contractor shall notify the Soil Engineer in advance of his intention to import soil from any source outside the project areas, and shall permit the Soil Engineer to sample as necessary for the purpose of making tests to establish the qualities of these materials. 3.5 During operations, soil types other than those analyzed in the report of the soil investigation may be encountered by the Contractor. The Soil Engineer shall be consulted to determine the suitability of these soils. Wildan Associates Page No. 15 Palomar Airport Road December 1, 1986 Job No. 4222 4. PLACING, SPREADING, AND COMPACTING FILL MATERIALS 4.1 Fill materials should be placed in layers, which, when compacted, would permit adequate bonding and compaction. Each layer shall be spread evenly and shall be thoroughly mixed during the spreading to provide uniformity of material in each layer. 4.2 After each layer has been placed, mixed and spread evenly, it should be thoroughly compacted to a relative compaction of not less than 90 percent of the maximum dry density as determined by ASTM Test Method D-1557, unless otherwise specified. 4.3 Compaction shall be continuous over the entire area and the equipment shall make sufficient trips to ensure that the desired density has been obtained throughout the entire fill. Wildan Associates Page No. 16 Palomar Airport Road December 1, 1986 Job No. 4222 5. INSPECTION 5.1 Observations and compaction tests shall be made by the Soil Engineer during the filling and compaction operations. 5.2 The standard test used to define maximum densities of the soil will be the ASTM Test Method D-1557. Compaction of the fill shall be expressed as the percent of the field density to the maximum density. When the compaction of the fill is below the specified value, the particular layer or portion shall be recompacted. The number and kind of tests shall be determined by the Soil Engineer. 5.3 During construction, the contractor shall properly grade all excavated surfaces to provide positive drainage and prevent the ponding of water. He shall control surface water to avoid damage to adjoining properties or to finished work on the site. o o Wildan Associates Page No. 17 Palomar Airport Road December 1, 1986 Job No. 4222 SLOPES All fill or cut slopes shall be at no greater than 2 to 1 (horizontal to vertical) slope. Landscaping and brow ditches are recommended to reduce surface erosion and failure. All future slopes must be benched and keyed into existing slopes. The slope in section "D" should have a stabilization fill place adjacent to the area of slumping. Further examination would be necessary to determine drain placement. PAVEMENT SECTION "R"-Value samples were taken from two locations along Palomar Airport Road representing changes in soil type or color. The existing structural section was measured for analyses at each location and the measurements are presented in Table 2. o o Wildan Associates Page No. 18 Palomar Airport Road December 1, 1986 Job No. 4222 Pavement structural section recommendations were developed using a basement soil "R"-value of 21. Table 3 shows computation for developing three alternate structural sections. The City of Carlsbad, design table, Plate 2 was used to determine traffic index (T.I.) and minimum asphaltic concrete thickness. The design assumes the use of Class II processed aggregate base course. Disintegrated granite (D.G.) (minimum "R"-value of 50) would only be used as select import for a subbase course. Recommended for the asphaltic pavement section is a 4 inch single lift of type B, 3/4 inch medium a.c. base course and 2 inch surface course of type "B", 1/2 inch medium a.c., both with AR-4000 asphalt. o o Wildan Associates Page No. 19 Palomar Airport Road December 1, 1986 Job No. 4222 TABLE NO. 2 BASEMENT SOIL SAMPLES LOCATIONS AND EXISTING SECTION MEASUREMENTS Sample No. 1: 720 feet east of Yarrow Drive, east bound lane, 15 feet north of curb line. A.C. - 3 1/2 inches, 1 lift of 1/2 inch medium A.C. Aggregate base - 71/2 inches, disintegrated granite. Subgrade - Tan clayey silty fine sand. Sample No. 2: 475 feet west of El Camino Real, east bound lane, added grade and pave for right turn lane, 15 feet north of curb line. A.C. - 6 inches, 1 lift of 1/2 inch medium A.C. Aggregate base - 13 inches, Class II aggregate base material. Subgrade - Light brown silty fine sand with trace clay. o Wildan Associates . Page No. 20 Palomar Airport Road December 1, 1986 Job No. 4222 TABLE NO. 3 RECOMMENDED SECTION DESIGN ALTERNATIVES Basement Soil R-Value 21 Traffic Index (Prime Arterial) 9.0 Minimum a.c. Thickness, ft. (inch) 0.5' (6") Minimum cover required (GE) ft. (inch) 2.29 (27.5") Note: Materials referenced to Cal Trans Standard Specifications for aggregate subbase, aggregate base, and asphaltic concrete. Alternative 1: Actual Thickness Feet Inch 0.50 6 1.26 15 1.75 21 Alternative 0.50 6 0.50 6 0.84 10 1.83 22 Alternative 0.50 6 0.83 10 0.48 6 1.83 22 Course Asphaltic Concrete Class II Agg. Base 2: Asphaltic Concrete Class II Agg. Base Class II Agg. Subbase 3: Asphaltic Concrete Class II Agg. Base Class II Agg. Subbase (Gf) 1.80 1.10 1.80 1.10 1.00 1.80 1.10 1.00 Gravel Equivalent (GE) Feet 0.90 1.39 2.29 0.90 0.55 0.84 2.29 0.90 0.91 0.48 2.29 o o Wildan Associates Page No. 21 Palomar Airport Road December 1, 1986 Job No. 4222 LIMITATIONS AND UNIFORMITY OF CONDITIONS The recommendations presented in this report are contingent upon our review of final plans and specifications. It is recommended that Testing Engineers-San Diego, be retained to provide continuous soil engineering services during the earthwork operations. This is to observe compliance with the design concepts, specifications or recommendations and to allow design changes in the event that subsurface conditions differ from those anticipated prior to start of construction. The recommendations and opinions expressed in this report reflect our best estimate of the project requirements based on an evaluation of the subsurface soil conditions encountered at the subsurface exploration locations and the assumption that the soil conditions do not deviate appreciably from those encountered. o o Wildan Associates Page No. 22 Palomar Airport Road December \, 1986 Job No. 4222 It should be recognized that the performance of the foundations and/or cut and fill slopes may be influenced by undisclosed or unforeseen variations in the soil conditions that may occur in the intermediate and unexplored areas. Any unusual conditions not covered in this report that may be encountered during site development should be brought to the attention of the soil engineer so that he may make modifications if necessary. This office should be advised of any changes in the project scope or proposed site grading so that it may be determined if the recommendations contained herein are appropriate. This should be verified in writing or modified by a written addendum. The findings of this report are valid as of this date. Changes in the condition of a property can, however, occur with the passage of time, whether they be due to natural processes or the work of man on this or adjacent properties. In addition, changes in the State-of-the-Art and/or Government Codes may occur. Due to such changes, the findings of this report may be invalidated wholly or in part by changes beyond our control. o o Wildan Associates Page No. 23 Palomar Airport Road December 1, 1986 Job No. 4222 Therefore, this report should not be relied upon after a period of two years without a review by us verifying the suitability, the conclusions, and recommendations. In the performance of our professional services, we comply with that level of care and skill ordinarily exercised by members of our profession currently practicing under similar conditions and in the same locality. The client recognizes that subsurface conditions may vary from those encountered at the locations where our borings, surveys, and explorations are made, and that our data, interpretations and recommendations are based solely on the information obtained by us. We will be responsible for those data, interpretations and recommendations, but shall not be responsible for the interpretations by others of the information developed. Our services consist of professional consultation and observation only, and no warranty of any kind whatsoever, expressed or implied, is made or intended in connection with the work performed or to be performed by us, or by our proposal for consulting or other services, or by our furnishing of oral or written reports or findings. o o Wildan Associates Page No. 24 Palomar Airport Road December 1, 1986 Job No. 4222 It is the responsibility of the owners, or their representatives to ensure that the information and recommendations contained herein are brought to the attention of the engineer and architect for the project and incorporated into the project's plans and specifications. It is further their responsibility to take the necessary measures to ensure that the contractor and his subcontractors carry out such recommendations during construction. o Testing Engineers-San Diego UNIFIED SOIL CLASSIFICATION PLASTICITY CHART 60 50 40 r30 20 10 CL V CH •>°/ ML ond OL OH ond MH 0 TO 20 30 40 50 60. 70 80 90 100 Liquid Limit "t>N'3> o>.1v> 0o CM oin z d c 0 =in £ O O>u o« Z 0 2.=? i« 5§ io ». <J 0 **> of £ 0> o2 GROUP SYMBOL GW GP GM GC SW SP SM SC TYPICAL NAMES Well-groded gravels, gravel-sand mixtures, little or no fines Poorly graded gravels, gravel -sand mixtures, little or no fines Silty. gravels, gravel- sand-silt mixtures Clayey gravels, gravel sand-clay mixtures Well-graded sands, gravelly sands, little or no fines Poorly graded sands, gravelly sands, little or no fines Silty sands, sand-silt mixture Clayey sands, sand- clay mixtures V>a> u> OOCM 0 c0w £ _J w 0 »"> -5a Ejjj </> Z a, ^ "~o: oo '«-1 £ UJ 02 e "- -o "5f 1 a> o GROUP SYMBOL ML CL QL MH CH OH Pt TYPICAL NAMES Inorganic silts and very fine sands, rock flour silty or clayey fine sands, or clayey silts with slight plasticity Inorganic clays of low to medium plasticity, gravelly clays, sandy clays, silty clays, lean clays Organic silts and organic silty clays of low plasticity Inorganic silts, micaceous or diatomaceous fine sandy or silty soils, elastic silts Inorganic clays of high plasticity, fat clays Organic clays of medium to high plasticity, organic silts Peat ond other highly organic soils NOTE: 1)Group symbol presented in SYMBOL column on BORING LOG. 2) The A line is an empirical relationship established by A. Casagrande. PLATE CITY OrCARLSBAD DESIGN TABLE o MINIMUM SIR I.I. *ade -Value , 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 46 48 50 52 54 4.0 ALLEY AC 3 3 3 UG 6 5 4 4.5 CUL-DE- SAC AC 3 3 3 UG 8 7 6 UCTURAL SECTION IK ii.'CHES Tl = 1.35 (EUL) b.O LOCAL STREET AC 3 3 3 3 3 , UG 10 9 8 7 6 670 COLLECTOR AC 4 4 4 4 4 4 4 4 DB 13 12 11 10 9 8 7 6 7.0 LIGHT INDUSTRIAL AC 4 4 4 4 4 4 4 4 4 4 AB 15 14 13 12 11 10 9 8 7 6 . 8.0 SECONDARY ARTERIAL AC 4 4 4 4 4 4 4 4 4 4 4 4 4 AB 18 17 16 15 14 13 12 11 10 9 8 7 6 8.5 MAJOR ARTERIAL AC 5 5 5 5 5 5 5 5 5 5 5 5 5 Ab 18 17 16 15 14 13 12 11 10 9 8 7 6 3.0 PRIME ' ARTERIAL AC 6 6 6 6 6 6 6 6 6 6 6 6 6 AB 18 17 16 15 14 13 12 11 10 9 8 7 6 NOTES; 1. A.C.Asphalt Concrete 2. D.G. = Disintegrated Granite, R = 73 min., S.E. = 30 min. conforming to Section 400-2.3 of Green Book. 3. A.B. = Crushed Aggregate Base, R = 80 min., tS.E. = 50 min. conforming to Section 200-2.2 of Green Book. 4. The bottom figures listed are the minimum permitted. «. •^ APPROVED DATE £/ry afrrtt&rt0> y City Engineer Date PLATE 2