ESBD_File_331886_IFB CIPS23-012 16 Waterline Extension Lakeline Blvd._ATTACHMENT I - Geotechnical Report.pdf

ROCK ENGINEERING & TESTING LABORATORY, INC.

7 ROUNDVILLE LANE AUSTIN, TEXAS, 78664

OFFICE: (512) 284-8022 FAX: (512) 284-7764 www.rocktesting.com

GEOTECHNICAL ENGINEERING

CONSTRUCTION MATERIALS

ENGINEERING & TESTING

SOILS ASPHALT CONCRETE

February 23, 2022

Walter P Moore 221 West 6th Street, Suite 800 Austin, Texas 78701

Attention: Gabriel Morales, P.E.

gmorales@walterpmoore.com

SUBJECT: GEOTECHNICAL ENGINEERING EVALUATION

PROPOSED 16-INCH WATERLINE EXTENSION

LAKELINE BOULEVARD

LEANDER, TEXAS

URETL Project No.: G322010

Dear Mr. Morales, P.E., Introduction

In accordance with our agreement, Rock Engineering & Testing Laboratory, Inc. (RETL) (Texas Professional Engineering Firm #2101) has performed a Geotechnical Engineering Evaluation for the above referenced project. The results of our services are presented in the accompanying Letter Report, an electronic copy of which is being transmitted herewith.

Authorization

Our services were performed in accordance with RETL Proposal No. RGP100721BR1 dated December 21, 2021. The proposal contained a scope of work, fee, and limitations.

The proposal was approved and signed by Ms. Susan Turrieta, P.E. representing Walter P Moore and returned to RETL via email.

Purpose and Scope

The purpose of this study was to evaluate soil and rock conditions along the proposed 16-inch Waterline Extension Project. The scope of this study included field exploration and testing, laboratory testing, engineering analysis and evaluation of the subsurface conditions, and preparation of this Letter Report.

ATTACHMENT I

Walter P Moore PROPOSED 16-INCH WATERLINE February 23, 2022 Lakeline Boulevard RETL Project No. G322010 Leander, Texas

The scope of services did not include an environmental assessment. Any statements in this report, or on the Log of Boring, regarding odors, colors, unusual or suspicious items or conditions are strictly for the information of the client.

General

The results of the field and laboratory testing services reported herein are considered sufficient in detail and scope for the engineers to evaluate excavation operations for the water line installation. If the civil engineer requires additional geotechnical design parameters to complete the design and the requested information can be obtained from the agreed upon scope of work, RETL will provide the requested information as a supplement to this report.

The Geotechnical Engineer states that the findings contained herein, have been presented after being prepared in a manner consistent with the level of care and skill practicing contemporaneously under similar conditions in the locality of the project. RETL Standard Practice for Minimum Requirements for Agencies

Engaged in the Testing and/or Inspection of Soil and Rock as Used in Engineering Design and Construction 3740). No other representations are expressed or implied, and no warranty or guarantee is included or intended.

Project Description

Based on our review of information provided, RETL understands that the proposed project will include the construction of approximately 3,900-feet of new 16-inch waterline. The proposed waterline will be constructed on the eastern side of Lakeline Boulevard with limits from approximately 2,700-feet north of Stinnett Drive to the northside of Hero Way.

Field Exploration

The field exploration completed to evaluate the engineering characteristics of the subsurface conditions included drilling four (4) test borings with a truck-mounted drill rig and recovering samples of the subsurface materials encountered at the test boring location. Walter P Moore personnel determined the number and depth of the test borings.

RETL personnel staked the test boring locations at the subject site. Test Boring B-4 was performed in the ditch adjacent to the roadway due to the presence of underground utilities near the proposed alignment. The test borings were completed by an RETL drilling crew. A Test Boring Location Plan, which is a reproduction of an aerial image from Google Earth, is included as an attachment to this report.

The test borings were completed with the truck-mounted drill rig using air rotary drilling methods to advance the boreholes to the termination depths. Disturbed samples were obtained employing split-barrel sampling procedures in general accordance with the

Penetration Test and Split-Barrel Sampling of Soils ASTM D1586).

RETL Project No. G322010 Leander, Texas

During the sample recovery operations, the soils encountered were classified and recorded on Field Logs Standard Guide for Field Logging of Subsurface Exploration of Soil and Rock drilling operations and obtaining the groundwater observations, the boreholes were backfilled with excavated cuttings.

The samples were classified in the field, placed in plastic bags, marked according to test boring number, depth and any other pertinent field data, stored in special containers, and delivered to the laboratory for testing.

Water level observations were obtained during the drilling operations and are noted on the Logs of Boring attached. The amount of water in an open borehole largely depends on the permeability of the subsurface materials encountered at the test boring location.

The ground surface elevations at the test boring locations were not provided at the time this report was prepared. The depths referred to in this report are measured from the existing ground surface elevations at the test boring locations during the time of our field investigation.

Laboratory Testing Program

A laboratory-testing program was conducted to supplement the information obtained during the field exploration in order to provide additional pertinent engineering characteristics of the subsurface materials encountered. The laboratory-testing program included supplementary visual classification (ASTM D2487) and water content tests (ASTM D2216) on samples obtained. In addition, selected samples were subjected to Atterberg limits tests (ASTM D4318) and percent material finer than the #200 sieve tests

(ASTM D1140).

The laboratory-testing program was conducted in general accordance with applicable ASTM Specifications. The results of the laboratory testing are included on the attached Logs of Boring.

Subsurface Conditions

The types of subsurface materials encountered at the test boring locations have been visually classified and are described in detail on the Logs of Boring. The results of the standard penetration tests, water level observations and laboratory tests are presented on the Logs of Boring in numerical form. Representative samples of the subsurface materials were placed in polyethylene bags and are now stored in the laboratory for further analysis, if desired. Unless notified to the contrary, the samples will be disposed of three (3) months after issuance of this report.

The stratification of the soil and rock, as shown on the Logs of Boring, represents the subsurface conditions at the actual test boring locations. Variations may occur between, or beyond, the boring location. Lines of demarcation represent the approximate boundary between different soil and rock types, but the transition may be gradual, or not clearly defined.

RETL Project No. G322010 Leander, Texas

It should be noted that, whereby the test borings were drilled and sampled by experienced drillers, it is sometimes difficult to record changes in stratification within narrow limits. In the absence of foreign substances, it is also difficult to distinguish between discolored soils and clean soil fill. The subsurface conditions encountered in the test borings drilled at the subject site have been summarized and the soil properties including classification, strength, plasticity, and grain size are provided in the following tables:

TEST BORINGS B-1 & B-2

D Description LL PI C e -#200 N

0-4 CLAYEY Sand 35-37 17 2,000 0 120 52-56 20-43

4-10 LIMESTONE --- --- >5,000 0 130 --- 50/5 1

TEST BORING B-3

D Description LL PI C e -#200 N

0-1 Fat CLAY 75 47 2,000 0 120 82 31

1-6½ CLAYEY Gravel 42 24 3,000 0 120 20 27-42

6½-10 LIMESTONE --- --- >5,000 0 130 ---

TEST BORINGS B-4*

D Description LL PI C e -#200 N

0-1 CLAYEY Sand 72 46 2,000 0 120 69 28

1-10 LIMESTONE --- --- >5,000 0 130 ---

*Test Boring was performed at an elevation approximately 3-feet below the grade along the adjacent alignment

Where: D = Depth in feet below existing grade LL = Liquid Limit (%) PI = Plasticity Index C = Average Soil Cohesion, psf (undrained) = Angle of Internal Friction, deg. (undrained) e = Effective Soil Unit Weight, pcf -#200= Percent Material Finer than a #200 Sieve N= Standard Penetration Test (blows per foot)

RETL Project No. G322010 Leander, Texas

Based on the observations completed during the field investigation and our experience with similar projects in the vicinity of the subject site, the following items should be noted:

The limestone materials at this site are hard in consistency; high powered rock excavation equipment or other comparable heavy-duty earth moving equipment, such as a hoe ram breaker and rock bucket, may be necessary to excavate these materials at this site. Interbedded seams of very hard clay may be encountered within the limestone strata.

strength and difficulty in excavation.

Detailed descriptions of the subsurface conditions encountered at the test boring location are provided on the Logs of Boring included in the Appendix.

Groundwater Observations

Groundwater (GW) was not encountered during drilling nor measured upon completion of the drilling operations. Based on observations made in the field and moisture contents obtained in the laboratory, it appears that groundwater at this site may be encountered at depths greater than the 10-foot depth, the deepest termination depth of the test borings.

It should be noted that water levels in open boreholes may require several hours to several days to stabilize depending on the permeability of the soils and that groundwater levels at this site may be subject to seasonal conditions, recent rainfall, drought or temperature effects.

OSHA Soil Type Classification

The tables below provide summaries of the OSHA Soil Type Classification for the subsurface materials encountered at the test boring locations to the depth of 10-feet:

OSHA SOIL TYPE CLASSIFICATION; BORING B-1

D Soil Description OSHA Soil Type Classification

0-4 Cohesive Soil Above the Water Table Type B

4-10 Rock Above the Water Table Type A

OSHA SOIL TYPE CLASSIFICATION; BORING B-2

D Soil Description OSHA Soil Type Classification

0-3 Cohesive Soil Above the Water Table Type B

3-10 Rock Above the Water Table Type A

RETL Project No. G322010 Leander, Texas

OSHA SOIL TYPE CLASSIFICATION; BORING B-3

D Soil Description OSHA Soil Type Classification

0-6½ Cohesive Soil Above the Water Table Type B

6½-10 Rock Above the Water Table Type A

OSHA SOIL TYPE CLASSIFICATION; BORING B-4

D Soil Description OSHA Soil Type Classification

0-1 Cohesive Soil Above the Water Table Type B

1-10 Rock Above the Water Table Type A determination of the OSHA Soil Type during excavation of the soils at the jobsite. Slope protection for excavations greater than 20-feet deep shall be designed by a Professional Engineer registered in the State of Texas.

The maximum allowable slopes during construction for OSHA soil types are provided in the following table:

GUIDELINES FOR MAXIMUM ALLOWABLE SLOPES

Soil or Rock Type

Stable Rock Vertical

Type A ¾: Horizontal: 1 Vertical

Type B 1 Horizontal: 1 Vertical

Type C 1½ Horizontal: 1 Vertical

Guidelines for maximum allowable slopes were obtained from OSHA documents, but do not take into account any recent revisions or the stability of long-term unprotected slopes.

Long term unprotected slopes will likely require flatter slopes. The guidelines presented herein for slopes does not imply RETL is taking responsibility for construction site safety. This responsibility falls entirely upon the contractor and his Responsible Person. RETL anticipates that the contractor will comply with all rules, ordinances and other requirements to comply with safe construction practices.

RETL Project No. G322010 Leander, Texas

General Comments

If significant changes are made in the character or location of the proposed Water Line Extension, a consultation should be arranged to review any changes with respect to the prevailing soil conditions. At that time, it may be necessary to submit supplementary recommendations.

Sheeting, shoring, and bracing of trenches, pits and excavations should be made the responsibility of the contractor and should comply with all current and applicable local, state and federal safety codes, regulations and practices, including the Occupational Safety and Health Administration.

Closing

If there are any questions or if we can be of further assistance, please contact our office.

Sincerely, Brian Geiger, P.E. Arnie K. Hammock, P.E.

Geotechnical Project Manager Vice President Round Rock

Attachments: Test Boring Location Plan Logs of Boring Key to Soil Classifications

ROCK ENGINEERING & TESTING LABORATORY, INC. (TBPE FIRM NO. 2101)

7 ROUNDVILLE LANE

ROUND ROCK, TEXAS 78664

(512) 284-8022

TEST BORING LOCATION PLAN

NO SCALE TEST BORING LOCATIONS ARE APPROXIMATE

Walter P Moore PROPOSED 16-INCH WATERLINE

RETL Project No. G322010 Leander, Texas