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Revised Proposal for Geotechnical Pavement Investigation BSK Proposal GL21-21837B W. Las Positas Boulevard September 15,2021 Pleasanton,California Page 3 • Depth of fill within the roadway, • Perceptible relationships between moisture content and proximity to tree roots, • Relationship of current moisture content and expansion potential, • Subgrade conditions in areas near storm drain crossings and drain inlets, • Subgrade conditions near the 1-680 east, Tassajara Creek, and Chabot Canal bridge approaches; and • Consolidation settlement potential. More detailed rationale was provided in our draft work plan, submitted on June 21, 2021, a portion of which is presented as an attachment to this proposal. Task 1—Pre-Field Activities This task will include project setup, permitting, field coordination, and administration of BSK's services. We will visit the site and mark our exploratory locations with white paint.We will call Underground Service Alert (USA North 811) a minimum of 72 hours prior to our field exploration and submit USA ticket(s) for utility clearance. During our site visit to mark proposed exploration locations,we recommend that a City representative familiar with the Site's underground utilities meet with us in the field to assist with identifying underground utilities that could be in conflict with our proposed exploration points. We will also hire a private utility locator to help locate detectable underground utilities near our proposed exploratory points. Prior to drilling,we will obtain drilling permits from Zone 7. An encroachment permit will be obtained from the City of Pleasanton prior to drilling. We assume that the encroachment permit fee will be waived because this project is commissioned by the City of Pleasanton, and that it will require site-specific traffic control plans as well as provision of full traffic control services by a licensed contractor during our investigation. Task 2—Subsurface Investigation We propose to explore the subsurface conditions at the Site by drilling twenty (20) hollow-stem auger borings to depths of approximately 7 to 40 feet BGS at the approximate locations shown on the attached Figures 1 and 2, Proposed Exploration Plans. As described in our draft work plan, we plan to perform continuous sampling in the upper 10 feet of each boring(where applicable),sampling every 2.5 feet from 10 to 30 feet BGS of each boring (where applicable), and sampling every 5 feet from 30 to 40 feet BGS (where applicable). To keep up with the continuous sampling schedule and avoid delaying the drilling progression,two professionals from BSK will work in tandem to maintain a log of the soils encountered, record the blow counts obtained at each sampling interval, and obtain samples for visual examination, classification,and laboratory testing.The soil sampling will be performed using Standard Penetration Test (SPT) and 2.5-inch inner diameter (I.D.) lined split spoon samplers as well as Shelby tubes if applicable. The strength characteristics of the cohesive soil samples recovered will be evaluated in the field using a hand-held pocket penetrometer. During our investigation, we will also measure the approximate depth to free groundwater if it is observed in our hollow-stem auger borings. Upon completion,the borings will