Loading...
The URL can be used to link to this page
Your browser does not support the video tag.
Edmonds LS1 DRAFT Geotechnical Investigation Plan 21-1-22415-001_R1.pdf
Edmonds Lift Station No. 1 Geotechnical Investigation Plan Seattle, Washington July 5, 2017 Submitted To: Tetra Tech, Inc. 1420 5th Avenue, Suite 550 Seattle, Washington 98101 By: Shannon & Wilson, Inc. th 400 N 34Street, Suite 100 Seattle, Washington 98103 21-1-22415-001 TABLE OF CONTENTS Page 1.0INTRODUCTION ..................................................................................................................1 2.0FIELD EXPLORATIONS .....................................................................................................1 3.0SOIL SAMPLING AND GROUNDWATER MEASUREMENT ........................................2 3.1Sonic Core Drilling and Sampling .............................................................................2 3.2Environmental Samples ..............................................................................................3 3.3Groundwater Monitoring ............................................................................................4 4.0LABORATORY TESTING ...................................................................................................4 4.1Geotechnical Testing ..................................................................................................4 4.2Environmental Testing ...............................................................................................4 TABLES 1Exploration Details FIGURES 1LS1-1 Site Layout 2LS1-2 Site Layout 3LS1-3 Site Layout 4LS1-4 Site Layout 21-1-22415-001 21-1-22415-001-R1.docx/wp/aya i ELSN.1 DMONDS IFT TATION O GIP EOTECHNICALNVESTIGATION LAN S,W EATTLEASHINGTON 1.0INTRODUCTION This Geotechnical Investigation Plan includes a discussion of the identifiedgeotechnical investigationlocations, anticipated site access limitations, anticipated drilling and sampling methods, anticipated piezometer locations, and anticipated field and laboratory testing. Shannon & Wilson, Inc. (Shannon & Wilson) will procure the drilling subcontractor directly. The City of Edmonds willprovide all necessary permits. The field and laboratory testing for the Edmonds Lift Station No. 1 Project(Project) willbe performed in one phase. The goal of this exploration plan is to characterize the subsurface conditions and determinefeasibility of trenchless construction methods for the installation of the gravitysewer to replace Lift Station No. 1. As such, if the conditions encountered in any particular boring appear to be unfavorable for trenchless methods, we will suspend the drilling program at the conclusion of that boring, and inquire with Tetra Tech and the City for direction on whether to proceed with the rest of the investigations. We assume that direction would occur over the phone, in the span of an hour or less, so that we do not incur delay or standby expenses. There will be no Geotechnical Report associated with this investigation. The proposed exploration locations are shown in Figures 1 through 4. Soil samples will be obtained, and both field and laboratory testing will be performed. The proposed exploration depths and other select details are summarized in Table 1. Exploration locations may be shifted from the locations shown in the figures based on the location of utilities, street-use, traffic control, or accesslimitations. The need for flaggers is not anticipated. We also note that sidewalk closures may be required at selected sites. 2.0FIELD EXPLORATIONS The approximate locations of the proposed borings are presented in Table 1 and shown graphically in Figures 1 through 4. Table 1 also provides the likely drilling equipment, depth and sampling information, and site constraints. In general, the depths of the borings were selected to extend approximately 10 feet below the currently proposed pipeline invert. Due to the relatively tight work areas at selected sites and to limit impacts totraffic, homes, and businesses, we will use a track-mounted sonic core drill rig for all the borings. Assuming a track rig is used, each of these borings will require a work area about 12 feet wide and 40 to 50 feet 21-1-22415-001 21-1-22415-001-R1.docx/wp/aya 1 long. Additional parking for up to three support vehicles and a staging area for a trailer and drums for drill spoilsis also required. Because of the density of utilities near the proposed locations of LS1-1 and LS1-4, the upper portion of these explorations will be vacuum-excavated prior to drilling (to a maximum depth of about 5 feet) to confirm the absence of utilities prior to drilling the borings. If native soils are encountered in a vacuum excavation hole at less than 5 feet deep, drilling willcommence, provided that there are no adjacent utility locating paint marks for potentially directionally drilled utilities (e.g., natural gas). Investigation-derived waste (IDW) generated by this work will generally consist of vacuum truck and drill cuttings and decontamination water(if required).The drilling subcontractor is responsible for disposing of the IDW generated from drilling activities in accordance with applicable local, state, and federal regulations and permits. If encountered, potentially contaminated IDW will beleft on site pending the results of analytical testing. Wepropose a staging area for the drums, materials, and other equipment located adjacent to boring LS1-3, near 326 Sunset Avenue. If no contamination is encountered, this staging area would be occupied for the duration of the explorations (planned to be four days). The anticipated site traffic control layout and work zone requirements are shown in Figures 1 through 4. The site dimensions are laid out on basemap images from the City of Edmonds geographic information system database. 3.0SOIL SAMPLING AND GROUNDWATER MEASUREMENT Soil samples will be collected from the borings for identification and testing purposes. Soil samples will be usedfor characterization and geotechnical laboratory index testing. Environmental soil samples may also be collected if contamination is suspected. Additional information for each sampling and testing method is discussed below. 3.1Sonic Core Drilling and Sampling The sonic core drilling method uses high-frequency vibratory motion applied to the top of the drill column, along with downward pressure and rotation, to obtain nearly continuous core samples in soil. As the drill column is advanced into the ground, a core of soil enters the core barrel. We will usea 3- or 4-inch-diameter core barrel for the sonic core borings.After advancing the core barrel a specific distance (a “run”), a casing is typically advanced over the core barrel drill string, the drill column and core barrel are then removed from the borehole, and the soil core is removed from the core barrel and extruded into plastic bags. 21-1-22415-001 21-1-22415-001-R1.docx/wp/lkn 2 Standard Penetration Tests will be performed at approximately 5-foot intervals in borehole LS1-2. These tests will be used to provide input to the selection of the engineering soil parameters. For soils above the first evidence of groundwater, a photoionization detector (PID) will be used to screen the soil for evidence ofpotential soil contamination(see Section 3.2). Geologic logging and photographing of the soil cores willbe performed at the Shannon & Wilson warehouse. Ageologist willreview the core and obtain grab samples at approximately 5-foot depth intervals. The grab samples will be stored in plastic jars and returned to the laboratory for geotechnical testing. 3.2Environmental Samples Although significant soil or groundwater contamination is not expected, drilling in developed areas always carries the risk of unexpected conditions. Field personnel willfield screen soil samples for potential contamination. Typical field screening includes PID screening for volatile organic compounds (VOCs), sheen testing, and visual and olfactory inspection for evidence of contamination. This observational method is generally not sufficient to detect the presence of heavy metal contamination, if present, which would require laboratory testing. If contamination is suspected, an environmental soil sample willbe collected and the City of Edmonds will be notified to discuss a course of action. In addition to notification, other measures need to be taken if contamination is suspected, including: Monitoring the soil and breathing zone in the working area with portable equipment. The health and safety plan will provide action levels for suspect contamination that are protective of human health. Installing casing to isolate suspect contaminated portions of boreholes to prevent cross contamination. Separately containerizing suspect contaminated IDW and labeling the containers for future disposal. If contamination is suspected or encountered, additional costs will likely arise from such items as analytical testing, decontamination of equipment, consultation with environmental engineers, standby of personnel and equipment while decisions are being made, time for telephone calls to key Project personnel, driving casing to seal suspect or contaminated portions of boreholes, time to re-drill in a new location (if required), and handling and disposal of contaminated IDW. 21-1-22415-001 21-1-22415-001-R1.docx/wp/lkn 3 3.3Groundwater Monitoring Groundwater observation wells willbe installed in the borings to provide groundwater elevation data and define various perched and artesian groundwater conditions that are anticipated to occur along the alignment. Field staff will take groundwater measurements approximately two and four weeks after borehole completion. 4.0LABORATORY TESTING Geotechnical testing of soil samples from the borings will be used to determine index properties. Groundwater testing could consist of hydrocarbon identification and total dissolved metals, if contamination is suspected. 4.1Geotechnical Testing Soil samples collected for geotechnical testing will be stored in sealedjars until tested. The proposed geotechnical testing consists of the following: Water content tests on soil samples to provide index parameters useful for correlating with soil behavior. Grain size analyses to evaluate soil gradation and provide index parameters useful for correlating with soil behavior, soil permeability, trenchless construction suitability, and other design and construction issues. Atterberg limits tests on fine-grained soil to provide index parameters useful for correlating with soil behavior and clogging potential. 4.2Environmental Testing Contamination is not anticipated to be encountered in any explorations; however, ifsoil contamination is suspected, environmental soil analytical tests should be performed. Samples would be kept on ice until delivered under chain of custody to the laboratory in less than 48 hours from collection. SHANNON & WILSON, INC. Michael D. Harney, PE Associate JCS:MDH:MSK/jcs 21-1-22415-001 21-1-22415-001-R1.docx/wp/lkn 4 SHANNON & WILSON, INC. 21-1-22415-001 Boring will be 3 to 4 feet west of marked water line. BNSF right of way extends into the street. East side of street and sidewalk dense with buried utilities. equipment. Boring location may be shifted onto Location will be used as staging area to park Lane shift may take up pedestrian pathway. Work Area Notes Boring location on sidewalk. Site Constraints pedestrian pathway. Estimated Date of Completion 7/31/2017 8/1/20178/2/20178/3/2017 EXPLORATION DETAILS Boring (feet) Depth and Sampling Depth 35454540 TABLE 1 1 of 1 Additional SPT @ 5' Sampling intervals Rig Type Drilling Equipment TrackTrackTrackTrack Drilling Method SonicSonicSonicSonic Approximate Address 7/5/2017 - Table 1 Exploration Details.xlsx ~206 Sunset Ave NW~232 Sunset Ave NW~326 Sunset Ave NW~610 Sunset Ave NW General Information Identification Boring LS1-1LS1-2LS1-3LS1-4 564 Notes 1: THIS MAP IS NOT TO BE USED FOR DESIGN OR CONSTRUCTION Encroachmentspotter This map is a user generated static output from an Internet mappingsite and is for reference only. Data layers that appear on this map mayor may not be accurate, current, or otherwise reliable. a or access Minor pedestrian With Work lanes P.M. day Shoulderzone minimum traffic 6:00 one 12'. work current be to 6H-6. 4-foot x 100' the A.M. to expected through about Figure maintainmaintain 7:00 be bepedestrians MUTCD is will willwillwill duration LS1-1 hours zonezonezone to Conformsassist for workworkworkworkwork Plan TheTheTheTheThe to iiiiiiii Site Ahead Work W20-1 Road Feet Ahead LS1-1 94.0 Work W20-1 Road Parking No 47.02 LS1-1 WGS_1984_Web_Mercator_Auxiliary_Sphere 0 © City of Edmonds 94.0 564 Notes 1: THIS MAP IS NOT TO BE USED FOR DESIGN OR CONSTRUCTION This map is a user generated static output from an Internet mappingsite and is for reference only. Data layers that appear on this map mayor may not be accurate, current, or otherwise reliable. Encroachment Minor With Work lanes P.M. day Shoulder traffic 6:00 one 10'. current be to 6H-6. x 120' A.M. to expected about Figure maintain 7:00 be be MUTCD is will willwill duration LS1-2 hours zonezone to Conforms for workworkworkwork Plan TheTheTheThe Site Ahead Work W20-1 Road Feet Ahead LS1-2 94.0 Work W20-1 Road 47.02 Parking No WGS_1984_Web_Mercator_Auxiliary_Sphere 0 © City of Edmonds 94.0 564 Notes 1: THIS MAP IS NOT TO BE USED FOR DESIGN OR CONSTRUCTION This map is a user generated static output from an Internet mappingsite and is for reference only. Data layers that appear on this map mayor may not be accurate, current, or otherwise reliable. for area assist staging to Encroachment a spotter as serve a or will access Minor zone lane work pedestrian With traffic The Work P.M. day. minimum Shoulder minimum 6:00 one 10'. 11-foot be to zone 6H-6. 4-foot x 120' A.M. to expected work about Figure maintainmaintain 7:00 the be be MUTCD is through will willwillwill duration LS1-3 hours zonezonezone pedestrians to Conforms for workworkworkworkwork days Plan TheTheTheTheThe 4 iiiiiiilllllll Site Feet Ahead LS1-3 94.0 Work W20-1 Parking Road No 47.02 WGS_1984_Web_Mercator_Auxiliary_Sphere 0 © City of Edmonds 94.0 564 Notes 1: THIS MAP IS NOT TO BE USED FOR DESIGN OR CONSTRUCTION This map is a user generated static output from an Internet mappingsite and is for reference only. Data layers that appear on this map mayor may not be accurate, current, or otherwise reliable. assist to Encroachment spotter a or access Minor lane pedestrian With traffic Work P.M. dayminimum Shoulder minimum 6:00 one 10'. 11-foot be to zone 6H-6. x4-foot 120' A.M. to expected work about Figure maintainmaintain 7:00 clear the be be MUTCD is throughdriveways will willwillwill duration LS1-4 hours zonezonezone topedestrians Conforms for leave workworkworkworkwork Plan Will TheTheTheTheThe lllllll Site W1-4 Feet Ahead 4 94.0 Work LS1 W20-1 Road Parking 47.02 No WGS_1984_Web_Mercator_Auxiliary_Sphere 0 © City of Edmonds 94.0