ESBD_File_336440_1. Attachment I _Geotechnical and Engineer's Reports.pdf

Geotechnical Engineering Services

Leander Lift Station Improvements Lift Stations # 2 & 6

Leander, Texas

Arias Project No. 2021-1440

Prepared For:

Jay Engineering Company

February 2022

Austin Corpus Christi Dallas/Fort Worth Eagle Pass San Antonio

13581 Pond Springs Road, Suite 210, Austin, Texas 78729 • Phone: (512) 428-5550 • Fax: (512) 428-5525

February 18, 2022

Arias Project No. 2021-1440 VIA Email: fphelan@gbateam.com

Mr. Frank Phelan, P.E.

Jay Engineering Company, A Division of GBA.

1500 C.R. 269

Leander, Texas 78641

RE: Report of Geotechnical Engineering Services

Leander Lift Station Improvements (Lift Stations # 2 & 6)

Dear Mr. Phelan:

Arias & Associates, Inc. (Arias) is pleased to submit this Report of Geotechnical Engineering

Services for the above referenced project. Our services were performed as outlined in our proposal dated January 7, 2022, and authorized on January 7, 2022.

The purpose of this geotechnical engineering study was to establish foundation engineering properties of subsurface soil and groundwater conditions present at the site. The scope of the study is to provide geotechnical engineering criteria for use by design engineers in preparing the foundation design.

We sincerely appreciate the opportunity of working with Jay Engineering Company on this project and look forward to our continued association throughout final design and construction phases.

Please do not hesitate to contact us about this report, or if we can be of further service.

Sincerely, ARIAS & ASSOCIATES, INC.

TBPE Registration No. F-32

Alexandros Sioutis, EIT Ahmed N. Ahsan, P.E.

Geotechnical Engineer Geotechnical Department Manager mailto:fphelan@gbateam.com

TABLE OF CONTENTS

Page

Arias & Associates, Inc. i Arias Job No. 2021-1440

INTRODUCTION

AUTHORIZATION AND SCOPE

FIELD EXPLORATION

LABORATORY TESTING

SUBSURFACE CONDITIONS

Area Geology

Site Stratigraphic and Engineering Properties

Groundwater

FOUNDATION RECOMMENDATIONS

Mat Foundation

Uplift Considerations

Modulus of Subgrade Reaction

Lateral Earth Pressures

CONSTRUCTION CONSIDERATIONS

General

Excavation Conditions

Site Drainage and Groundwater Control

GENERAL COMMENTS

Geotechnical Design Review

Subsurface Variations

Quality Assurance Testing

Standard of Care

Page

Arias & Associates, Inc. ii Arias Job No. 2021-1440

APPENDICES

APPENDIX A: FIGURES ............................................................................................................ A

VICINITY MAP ..................................................................................... FIGURE 1

GEOLOGIC MAP .................................................................................. FIGURE 2

BORING LOCATION PLAN ................................................................. FIGURE 3

SAMPLE PHOTOGRAPHS .................................................................. FIGURE 4

SITE PHOTOGRAPHS ......................................................................... FIGURE 5

APPENDIX B: BORING LOGS AND KEY TO TERMS .............................................................. B

APPENDIX C: LABORATORY DATA AND TEST PROCEDURES ........................................... C

APPENDIX D: GBA INFORMATION – GEOTECHNICAL REPORT .......................................... D

Tables Page

Table 1: Project Description

Table 2: Subsurface Conditions in Geotechnical Study

Table 3: Boring Summary Table

Table 4: Generalized Subsurface Conditions and Engineering Properties Lift Station 2

Table 5: Generalized Subsurface Conditions and Engineering Properties Lift Station 6

Table 6: Proposed Structure Summary

Table 7: Lateral “Active” Pressures for Below-Grade Walls

Table 8: Lateral “At-Rest” Pressures for Below-Grade Walls

Arias & Associates, Inc. 1 Arias Job No. 2021-1440

INTRODUCTION

The project consists of improvements to the existing lift stations, Numbers 2 and 6, located at 601

N US 183, Leander, Texas and 2451 Bagdad Rd., Cedar Park, Texas, respectively. The proposed improvements will include one (1) 24-ft deep wet well addition at each location. The project site locations are shown on the Vicinity Map presented on Figures 1A, 1B, and 1C in Appendix A.

Project and site conditions are summarized in the following tables.

Table 1: Project Description

Project Location Lift Station 2: 601 N US 183, Leander, Texas

Lift Station 6: 2451 Bagdad Rd. Cedar Park, Texas

Proposed Development 24 ft deep wet well

Recommended Foundation Wet Well - Mat Foundation

Table 2: Subsurface Conditions in Geotechnical Study

Existing Surface Conditions Grass area, and existing pavement

Lift Station 2: Predominant Soil Type

Stratum I – Fat Clay (CH), Sandy Fat Clay (CH), Lean Clay with Sand (CL)

Stratum II – Weathered Limestone and Limestone

Lift Station 6: Predominant Soil Type Stratum I – Fat Clay (CH)

Stratum II – Weathered Limestone and Limestone

Lift Station 2: Measured Plasticity

Indices and Percent passing No. 200 sieve

PI = 19, 30, 37

-200 = 66, 74, 96

Lift Station 6: Measured Plasticity

Indices and Percent passing No. 200 sieve

PI = 38, 39

-200 = 84, 98

Depth to Groundwater in the Borings

Groundwater was encountered at B-1 (Lift Station 6) at a depth of about of 11 feet at the time of drilling. Groundwater was not encountered at B-2. Groundwater conditions may be different at the time of construction.

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AUTHORIZATION AND SCOPE

The geotechnical investigation was authorized and performed as outlined in our proposal dated

January 7, 2022 and authorized on January 7,2022. The outlines the authorized and agreed upon scope services.

The purpose of the investigation was to obtain subsurface information adequate for (1) the selection of suitable type(s) of foundation with respect to cost and performance, compatible with the type of structure proposed, (2) the formulation of design criteria for the type of foundation selected, and (3) the selection of materials and compaction requirements for earth construction.

The scope of the investigation included (1) a field investigation for determining subsurface conditions and obtaining representative samples for classification and testing, (2) a laboratory testing program to aid in the classification of the substrata and to provide parameters for the selection of foundation criteria, and (3) engineering analyses and evaluations of the results of the field and laboratory data to aid in assessing the geology, foundation design and construction issues.

FIELD EXPLORATION

The field investigation consisted of drilling two (2) borings, designated B-1 and B-2, to a depth of

30 feet below existing grade. The borings were drilled in areas accessible to our truck-mounted drill rig. The approximate locations are shown on the Boring Location Plan presented on Figures

3A, 3B, and 3C in Appendix A. A boring summary table is presented below.

Table 3: Boring Summary Table

Site Boring

Designation

Drill Depth

(ft) Drill Date GPS Latitude GPS Longitude

Lift Station 2 B-1 30 1/25/2022 30°34'16.66"N 97°51'0.39"W

Lift Station 6 B-2 30 1/25/2022 30°32'9.17"N 97°50'52.35"W

The borings were sampled using either the split-barrel sampler while performing the Standard

Penetration Test (ASTM D1586) or seamless steel push-tubes for obtaining samples of cohesive strata (ASTM D1587). Rotary rock coring was performed in general accordance with ASTM

D2113. Boring depths were measured from the existing surface elevation at the time of drilling.

A truck-mounted drill rig using air rotary drilling methods together with the sampling tools noted was used to obtain samples. After completion of drilling, the boreholes were backfilled using the auger cuttings and bentonite mixture.

Arias & Associates, Inc. 3 Arias Job No. 2021-1440

Detailed descriptions of subsurface conditions encountered in the borings are presented on the

Boring Logs included in Appendix B. Sample type and interval are included on the individual soil boring logs at the respective sample depth. An Arias representative visually logged each recovered sample and selected representative samples for laboratory testing. Photographs of the samples are presented on Figures 4A, 4B, and 4C in Appendix A. Site drilling photographs are also shown in Figure 5 of Appendix A.

SPT N-values for those intervals where the sampler was advanced for a 12-inch penetration after the initial 6-inch seating and pocket penetrometer values in tsf are shown on the individual boring logs included in Appendix B. Rock Core Recovery (REC) and Rock Quality Designation (RQD) in percent are shown on the boring logs. The GPS coordinates (horizontal datum WGS 84) obtained using a hand-held GPS device are shown on the boring logs, and should be considered approximate. Drilling and groundwater notes are also shown on the boring logs.

Soil classifications and borehole logging were conducted during the exploration by one of our field engineering technicians working under the supervision of our Geotechnical Engineer. Final soil classifications, as seen on the boring logs included in Appendix B, were determined in the laboratory based on laboratory and field test results and applicable ASTM procedures. The key to the terms and symbols used on the logs and the field test procedures is also included in

Appendix B, following the boring logs.

LABORATORY TESTING

The laboratory testing program included identification and classification testing of all strata encountered in the subsurface. Soil classification tests included soil water content (ASTM

D2216), Atterberg limit determinations (ASTM D4318) and amount of material in soils finer than the No. 200 sieve (ASTM D1140), and unconfined compressive strength of rock (ASTM D7012).

Classification tests are presented on the boring logs at the respective sample depth included in

Appendix B, and presented graphically in Appendix C.

The soil laboratory testing for this project was done in accordance with applicable ASTM procedures with the specifications and definitions for these tests listed in Appendix C. Remaining soil samples recovered from this exploration will be routinely discarded following submittal of this report.

SUBSURFACE CONDITIONS

Area geology, generalized stratigraphy and groundwater conditions are discussed in the following sections. The subsurface and groundwater conditions are based on conditions encountered at the boring locations to the depths explored.

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Area Geology

According to the Geologic Atlas of Texas, Austin Sheet1, the project sites are mapped as being underlain by Comanche Peak Limestone (Kc) at Lift Station 6, and Keys Valley Marl (Kkv) at Lift

Station 2. A Geologic Map is presented on Figures 2A, 2B, and 2C in Appendix A.

Lift Station 6. The Comanche Peak Limestone is composed of alternating hard and soft argillaceous limestone with clayey limestone layers. Surficial remnants typically consist of fat and lean clay mixtures, becoming more lean clay and clayey gravel with depth to limestone.

Lift Station 2. The Keys Valley marl of the Walnut group is a cretaceous age limestone. In the

Leander area, the Keys valley Marl is typically comprised of alternating hard and soft, argillaceous limestone. Weathered remnants of the parent limestone consist of surficial fat and lean clay with various sand and limestone fragment content.

Site Stratigraphic and Engineering Properties

Subsurface conditions can be best understood by a thorough review of the Boring Logs included in Appendix B. In general, subsurface conditions for:

1) Lift Station 2 consist of surficial soils described as Fat Clay (CH), Sandy Fat Clay (CH), Lean Clay with Sand (CL), underlain by weathered limestone and limestone.

2) Lift Station 6 consist of surficial soils described as Fat Clay (CH) underlain by weathered limestone and limestone.

The surficial soils are referred to as Stratum I, and the limestone layer is referred to as Stratum

II. A summary of subsurface conditions and measured engineering properties is given in the following tables.

Table 4: Generalized Subsurface Conditions and Engineering Properties Lift Station 2

Stratum Depth

(ft) Material Type Index Test Strength Tests

Pavement to

0.5 ft

Asphalt 6 inches

PI

N/A

-200

N/A

N

N/A

PP

N/A

I

0.5 ft to

10.0 ft

Fat Clay (CH), Sandy Fat

Clay (CH), Lean Clay with

Sand (CL)

PI

19, 30, 37

-200

66, 74, 96

N

PP

1.5 to 4.5+

(avg = 4.0)

1 Garner, L.E. and Young, K.P. (1976), “Environmental Geology of the Austin Area: An Aid to Urban Planning”

Bureau of Economic Geology, The University of Texas at Austin, map and accompanying bulletin.

Arias & Associates, Inc. 5 Arias Job No. 2021-1440

Stratum Depth

(ft) Material Type Index Test Strength Tests

IIa

10.0 ft to

13.5 ft

Weathered Limestone

REC

N/A

RQD

N/A

SPT

50/2”

IIb

13.5 ft to

BTD

Tan and gray Limestone

REC

94 to 100

(avg = 98)

RQD

35 to 70

(avg = 54)

UC

78, 100, 134

Table 5: Generalized Subsurface Conditions and Engineering Properties Lift Station 6

Stratum Depth

(ft) Material Type Index Test Strength Tests

I to

4.0 ft

Fat Clay (CH)

PI

38, 39

-200

84, 98

N

N/A

PP

4.5+

IIa

4.0 ft to

5.0 ft

Weathered Limestone

REC

N/A

RQD

N/A

SPT

50/1”

IIb

5.0 ft to

BTD

Tan and gray Limestone

REC

87 to 100

(avg = 95)

RQD

0 to 67

(avg = 25)

UC

97 to 145

(avg = 128)

Where:

Depth - Depth from existing ground surface at the time of geotechnical study, feet PI - Plasticity Index, % -200 - Percent passing U.S. Standard No. 200 sieve, % N - Standard Penetration Test, N-value, in blows per foot (bpf) REC - Rock Core Recovery, % PP - Pocket Penetrometer, tsf RQD - Rock Quality Designation, % UC - Unconfined Compressive Strength, tsf BTD - Boring Termination Depth Avg - Average Value N/A - Not Applicable

Soil conditions may vary between the sampled boring locations. Transition boundaries or contacts, noted on the boring logs to separate soil types, are approximate. Actual contacts may be gradual and vary at different locations. If conditions encountered during construction indicate more variation than established as a result of this study, we should be contacted to evaluate the significance of the changed conditions relative to our recommendations.

Arias & Associates, Inc. 6 Arias Job No. 2021-1440

Groundwater

Groundwater was encountered at B-1 (Lift Station 2) at a depth of about 11 ft below existing ground surface. Groundwater was not encountered at B-2 (Lift Station 6) at the time of drilling.

Groundwater elevation may vary at the time of construction. Groundwater, if encountered, is oftentimes perched in Stratum I soils above the underlying less pervious limestone (Stratum II).

Groundwater conditions will be a function of antecedent rainfall conditions and may be different at the time of construction. Dewatering “means and methods” is the sole responsibility of the contractor.

FOUNDATION RECOMMENDATIONS

Proposed structures will include a 24 ft deep wet well. Please note that structural loading and the diameter of the wet well was not available at the time of this report’s preparation. A summary of provided structural information is presented in the following table.

Table 6: Proposed Structure Summary

Proposed Structure Approximate Dimensions

Wet Well 24 ft deep

Based on our understanding of the proposed construction and subsurface conditions encountered in the borings, we recommend the wet well be supported by either a mat foundation bearing 24 ft below existing grade. If the wet well is constructed using sloping techniques, then careful consideration must be given to selection and compaction of the backfill material. Accordingly, the following sections provide mat foundation, and deep foundation support recommendations.

Mat Foundation

The proposed wet well slab is proposed to be constructed 24 ft below existing grade. The borings encountered competent limestone at this depth. Thus, the wet well foundation may consist of a mat foundation, sized using an allowable net bearing pressure of 6,000 psf. The contractor may choose to install a mud mat on the approved foundation subgrade consisting of at least 4 inches of concrete to provide a working platform for the placement of reinforcing steel.

Uplift Considerations

After construction of the wet well, the groundwater level could rise to the ground surface within the backfilled excavations if not properly and permanently drained. The resulting buoyancy potential should be accounted for in the design of the structure where required. The ultimate uplift capacity of slab foundations is usually limited to the weight of the foundation plus the weight of

Arias & Associates, Inc. 7 Arias Job No. 2021-1440 any soil directly above the foundation. If additional uplift capacity is required, one or more of the following options can increase the capacity:

• Extending a perimeter "lip" of sufficient size around the base of proposed below-ground structures to use the unit weight of the backfill soil directly above the lip. We recommend using a total unit weight of 120 pcf, a submerged unit weight of 58 pcf and assuming the groundwater level at ½ the height of the wall as measured from the top of the foundation slab; or

• Using tension piles or soil/rock anchors to resist uplift forces.

The calculated ultimate uplift capacity should be reduced by an appropriate factor of safety to compute the allowable uplift resistance. We recommend using a minimum factor of safety of 1.5.

Modulus of Subgrade Reaction

For a continuously reinforced flat slab, the reinforcement requirement is intended to control shrinkage and temperature cracking. The thickness of the slab and the amount of steel reinforcement should be selected by the structural engineer to resist the proposed structural loads. A modulus of subgrade reaction (k-value) of 450 pci may be used, if needed, for design of the slab. This value is for a 1-foot square plate and should be corrected for the size and shape of the loaded area accordingly. The slab design and slab support (k-value) will need to be considered for slab loads.

Lateral Earth Pressures

Lateral pressures transmitted to below-grade walls can be evaluated by using the equivalent fluid density (EFD) values given in the tables below for “active” and “at-rest” conditions. Where there is sufficient wall movement, deflection, and/or rotation, the walls can be designed for the “active” condition. However, when rigid walls are restricted from moving, the walls should be designed for the “at-rest” condition.

The “EFD - undrained condition” values in Tables 7 and 8 should be used if there is a chance for hydrostatic forces to develop and a drainage system is not provided behind the walls; otherwise, the “EFD – drained condition values” can be used. If free draining backfill is provided behind the walls, we recommend that a positive slope grade coupled with pavement or the use of a clay cap, be provided to help reduce the chances for surface water infiltration behind the walls.

Surcharge loads such as foundation, slab loads, and/or truck traffic should also be considered in the analysis of below-grade walls. The lateral pressures due to surcharge loading (such as slab loads), which act as uniform pressures on the walls, should be calculated by multiplying the surcharge pressure by the applicable lateral earth pressure coefficients given in the following table. A surcharge value of 250 psf should be used for below grade walls subject to vehicular traffic.

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Table 7: Lateral “Active” Pressures for Below-Grade Walls

Backfill Type

Estimated

Total Soil

Unit

Weight, (pcf)

Effective

Soil Unit

Weight, (pcf)

Active Earth

Pressure

Coefficient, (ka)

Equivalent Fluid Density

(EFD)

Drained

Condition, (pcf)

Undrained

Condition, (pcf)

On-site Soils 120 58 0.36 45 85

Open-Graded Gravel

(ASTM C33 No.57 or 67) 105 43 0.33 35 75

TxDOT Item 247, Type A, Grade 1-2 or 5 125 63 0.31 40 80

Table 8: Lateral “At-Rest” Pressures for Below-Grade Walls

Backfill Type

Estimated

Total Soil

Unit

Weight, (pcf)

Effective

Soil Unit

Weight, (pcf)

At-Rest

Earth

Pressure

Coefficient, (ko)

Equivalent Fluid Density

(EFD)

Drained

Condition, (pcf)

Undrained

Condition, (pcf)

On-site Soils 120 58 0.53 65 95

Open-Graded Gravel

(ASTM C33 No.57 or 67) 105 43 0.50 55 85

TxDOT Item 247, Type A, Grade 1-2 or 5 125 63 0.47 60 90

Notes:

1. The equivalent fluid unit density (EFD) values are for triangular distribution of lateral earth pressures on the wall; surcharge loads impose a rectangular stress distribution.

2. Heavy compaction rollers should operate no closer than 5 feet from the wall. Hand operated compaction equipment, such as vibratory plates, should be used directly behind the wall.

If a vertical drain is provided behind the walls, it should consist of a minimum of 12 horizontal inches of clean, free-draining open-graded gravel. The free draining backfill should be placed in maximum 12-inch lifts and tamped in place. For below grade walls with drainage, place a minimum 6-inch diameter perforated pipe system near the bottom of the walls to prevent buildup of hydrostatic pressures. Perforations should be placed downwards and the pipe should be wrapped with a suitable filter fabric to prevent clogging. The pipe should be discharge well away from the structures.

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If drainage is not provided behind the walls, the below grade walls should be designed for the undrained condition as previously noted. For this scenario, buoyancy considerations would also need to be made. If necessary, the foundation can be extended beyond the wall to provide additional uplift resistance from the effective unit weight of the backfill.

CONSTRUCTION CONSIDERATIONS

General

Details regarding excavation, dewatering, site safety, shoring and excavation retention, selection of machinery and equipment, and benching and sloping requirements are considered construction means and methods, and thus, are the sole responsibility of the Contractor.

The information presented herein pertaining to groundwater control and trenching and shoring is for informational purposes only. Temporary access pits used for construction are typically designed by the contractor. Additional information should be collected by the Contractor as they deem appropriate.

Excavation Conditions

The designers and contractor should expect that the soils/materials to be penetrated by excavations may vary at locations away from our boring locations. The following information is provided based on the observation of our soil test borings and laboratory test results:

• Groundwater was encountered at 11-ft depth at B-1 during at the time of field exploration.

However, water may be encountered at variable depths due to seasonal variations, and perched groundwater tables. The “perched” water and/or potential groundwater could lead to trench excavation difficulties without adequate dewatering means and methods employed by the Contractor. If required, dewatering is considered “means and methods” and is the sole responsibility of the contractor.

• Instability of trench sides and bottoms may occur if loose granular soils or soft clay seams are present (especially if groundwater is encountered).

• Unconfined compressive strengths of limestone ranged from 78 to 145 tsf. Excavations extending into the limestone stratum will require use of heavy-duty track-mounted excavators and/or hydraulic rams. The Contractor should be prepared for and have experience with similar conditions.

Site Drainage and Groundwater Control

Good positive drainage during and after construction is very important to reduce induced settlement of existing fill that can detrimentally affect the performance of the planned development. Temporary dewatering measures may be required to allow the construction to be performed in the dry and shall be considered in the budget and schedule of the project. As

Arias & Associates, Inc. 10 Arias Job No. 2021-1440 indicated before, we highly recommend that the Contractor verifies the groundwater conditions before construction starts.

GENERAL COMMENTS

This report was prepared as an instrument of service for this project exclusively for the use of Jay

Engineering Company and the design team. If the development plans change relative to layout, size or anticipated loads or if different subsurface conditions are encountered, we should be informed and retained to ascertain the impact of these changes on our recommendations. We cannot be responsible for the potential impact of these changes if we are not informed.

Geotechnical Design Review

Arias should be given the opportunity to review the design and construction documents. The purpose of this review is to check to see if our recommendations are properly interpreted into the project plans and specifications. Please note that design review was not included in the authorized scope and additional fees may apply.

Subsurface Variations

Soil and groundwater conditions may vary between the sample boring locations. Transition boundaries or contacts, noted on the boring logs to separate soil/rock types, are approximate.

Actual contacts may be gradual and vary at different locations. The contractor should verify that similar conditions exist throughout the proposed area of excavation. If different subsurface conditions or highly variable subsurface conditions are encountered during construction, we should be contacted to evaluate the significance of the changed conditions relative to our recommendations.

Quality Assurance Testing

The long-term success of the project will be affected by the quality of materials used for construction and the adherence of the construction to the project plans and specifications. As

Geotechnical Engineer of Record (GER), we should be engaged by the Owner to provide Quality

Assurance (QA) testing. Our services will be to evaluate the degree to which constructors are achieving the specified conditions they’re contractually obligated to achieve, and observe that the encountered materials during earthwork for foundation and pavement installation are consistent with those encountered during this study. In the event that Arias is not retained to provide QA testing, we should be immediately contacted if differing subsurface conditions are encountered during construction. Differing materials may require modification to the recommendations that we provided herein.

Arias has an established in-house laboratory that meets the standards of the American Standard

Testing Materials (ASTM) specifications of ASTM E-329 defining requirements for Inspection and

Testing Agencies for soil, concrete, steel and bituminous materials as used in construction. We

Arias & Associates, Inc. 11 Arias Job No. 2021-1440 maintain soils, concrete, asphalt, and aggregate testing equipment to provide the testing needs required by the project specifications. All of our equipment is calibrated by an independent testing agency in accordance with the National Bureau of Standards. In addition, Arias is accredited by the American Association of State Highway & Transportation Officials (AASHTO), the United

States Army Corps of Engineers (USACE) and the Texas Department of Transportation (TxDOT), and also maintains AASHTO Materials Reference Laboratory (AMRL) and Cement and Concrete

Reference Laboratory (CCRL) proficiency sampling, assessments and inspections.

Furthermore, Arias employs a technical staff certified through the following agencies: the National

Institute for Certification in Engineering Technologies (NICET), the American Concrete Institute

(ACI), the American Welding Society (AWS), the Precast/Prestressed Concrete Institute (PCI), the Mine & Safety Health Administration (MSHA), the Texas Asphalt Pavement Association

(TXAPA) and the Texas Board of Professional Engineers (TBPE). Our services are conducted under the guidance and direction of a Professional Engineer (P.E.) licensed to work in the State of Texas, as required by law.

Standard of Care

Subject to the limitations inherent in the agreed scope of services as to the degree of care and amount of time and expenses to be incurred, and subject to any other limitations contained in the agreement for this work, Arias has performed its services consistent with that level of care and skill ordinarily exercised by other professional engineers practicing in the same locale and under similar circumstances at the time the services were performed.

Information about this geotechnical report is provided in the GBA publication included in Appendix

D.

Arias & Associates, Inc. Arias Job No. 2021-1440

APPENDIX A: FIGURES

13581 Pond Springs Road, Suite 210, Austin, Texas 78729 Phone: (512) 428-5550 • Fax: (512) 428-5525

VICINITY MAP

Date: February 14, 2022 Job No.: 2021-1440

Figure 1A Drawn By: CM Checked By: AS

Approved By: AS Scale: N.T.S.

Map Source: Google Earth Professional

Sites

Lift Station#6

Leander, Texas

Date: February 14, 2022 Job No.: 2021-1440

Figure 1B Drawn By: CM Checked By: AS

Approved By: AS Scale: N.T.S.

Lift Station 6

Lift Station#2

Leander, Texas

Date: February 14, 2022 Job No.: 2021-1440

Figure 1C Drawn By: CM Checked By: AS

Approved By: AS Scale: N.T.S.

Lift Station 2

GEOLOGIC MAP

Date: February 14, 2022 Job No.: 2021-1440

Figure 2A Drawn By: CM Checked By: AS

Approved By: AS Scale: N.T.S.

USGS Geologic Map Texas Webviewer: https://txpub.usgs.gov/txgeology/ Professional

Site

Sites

LEGEND (Youngest to Oldest)

Kkv-Keys Valley Marl

Kc-Comanche Peak Limestone

Ked-Edwards Limestone

N https://txpub.usgs.gov/txgeology/

Leander, Texas

Date: February 14, 2022 Job No.: 2021-1440

Figure 2B Drawn By: CM Checked By: AS

Approved By: AS Scale: N.T.S.

Site

Site

Lift Station 2

LEGEND (Youngest to Oldest)

Kkv-Keys Valley Marl

Leander, Texas

Date: February 14, 2022 Job No.: 2021-1440

Figure 2C Drawn By: CM Checked By: AS

Approved By: AS Scale: N.T.S.

Site

Lift Station 6

LEGEND (Youngest to Oldest)

Kkv-Keys Valley Marl

BORING LOCATION PLAN

Date: February 14, 2022 Job No.: 2021-1440

Figure 3A Drawn By: AS Checked By: AS

Approved By: AA Scale: N.T.S.

PARTIAL BORING

LOCATION PLAN

Leander, Texas

Date: February 14, 2022 Job No.: 2021-1440

Figure 3B Drawn By: AS Checked By: AS

PARTIAL BORING

LOCATION PLAN

Leander, Texas

Date: February 14, 2022 Job No.: 2021-1440

Figure 3C Drawn By: AS Checked By: AS

Photo 1 – B-1 (0 – 22 ft)

Photo 2 – B-1 (22 – 30 ft)

SAMPLE PHOTOGRAPHS

Date: February 14, 2022 Job No.: 2021-1440 Figure 4A

Drawn By: CM Checked By: AS

Approved By: AS Scale: N.T.S.

Photo 3 – B-2 (0 – 13 ft)

Photo 4 – B-2 (13 – 23 ft)

Figure 4B

Photo 5 – B-2 (23 – 30 ft)

Figure 4C

Photo 1 – View of site from B-1, facing Southeast (1/25/2022)

Photo 2 – View of site from B-2, facing Northwest (1/25/2022)

SITE PHOTOGRAPHS

Figure 5

Arias & Associates, Inc. Arias Job No. 2021-1440

APPENDIX B: BORING LOGS AND KEY TO TERMS

6" Asphalt FAT CLAY (CH), stiff to hard, dark brown and brown

SANDY FAT CLAY with Gravel (CH), hard, tan and light gray, with calcareous deposits

LEAN CLAY (CL) with sand, very soft, tan and light gray, with calcareous deposits

Weathered LIMESTONE, tan

LIMESTONE, tan, slightly weathered, intensely to highly fractured, vuggy with clay seams

LIMESTONE, gray, slightly weathered, highly fractured with fossil fragments

LIMESTONE, gray, slightly weathered, highly fractured with fossil fragments

Borehole terminated at 30 feet

SS

T

T

T

T

SS

RC

RC

RC

REC=94

RQD=35

REC=100

RQD=57

REC=100

RQD=70

N=10

P=4.5+

P=4.5+

P=4.5+

P=1.5

N=50/2"

Nomenclature Used on Boring Log

Air rotary: 0 - 16 ft Rock core: 16 - 30 ft

Backfill: Cuttings/bentonite

Water encountered during drilling

Job No.: 2021-1440

Sampling Date: 1/25/2022 - 1/25/2022Project: Leander Lift Station Improvements Leander, TX

Arias Geoprofessionals

Soil Description

Split Spoon (SS) Thin-walled tube (T)

Rock Core (RC)

P = Pocket Penetrometer N = SPT Blow Count

REC = % Recovery RQD = Rock Quality Designation

PL = Plastic Limit

LL = Liquid Limit PI = Plasticity Index

WC = Water Content (%) -200 = % Passing #200 Sieve DD = Dry Density (pcf)

Uc = Compressive Strength (tsf)

Location: See Boring Location Plan

Groundwater Data:

First encountered during drilling: 11-ft depth

Field Drilling Data:

Coordinates: Hand-held GPS Unit Logged By: CM Driller: Austin Geo-Logic Equipment: Truck-mounted drill rig

Coordinates: N30o34'16.66'' W97o51'0.39''

-1

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B O

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G L

O G

K S

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-1

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-0

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R A

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K

S L

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B

UcDepth (ft)

Sample Type WC DDREC

RQD LL PI -200P, N

Boring Log No. B-1 (Lift Station 2)

FAT CLAY (CH), hard, dark brown, with sand

Weathered LIMESTONE, tan, with scattered clay

LIMESTONE, light tan, slightly weathered, intensely fractured with reddish and tan interbedded clay seams

LIMESTONE, light tan and tan, slightly weathered, intensely to highly fractured

LIMESTONE, tan and gray, slightly weathered, highly fractured

LIMESTONE, gray to light gray, slightly weathered, highly fractured s

LIMESTONE, gray to light gray, slightly weathered, highly to moderately fractured

Borehole terminated at 30 feet

T

T

SS

RC

RC

RC

RC

RC

REC=88

RQD=0

REC=87

RQD=8

REC=100

RQD=0

REC=100

RQD=23

REC=100

RQD=67

P=4.5+

P=4.5+

N=50/1"

Nomenclature Used on Boring Log

Air rotary: 0 - 5 ft Rock core: 5 - 30 ft

Backfill: Cuttings/bentonite

Job No.: 2021-1440

Sampling Date: 1/25/2022 - 1/25/2022Project: Leander Lift Station Improvements Leander, TX

Arias Geoprofessionals

Soil Description

Thin-walled tube (T) Split Spoon (SS)

Rock Core (RC)

P = Pocket Penetrometer N = SPT Blow Count

REC = % Recovery RQD = Rock Quality Designation

PL = Plastic Limit

LL = Liquid Limit PI = Plasticity Index

WC = Water Content (%) -200 = % Passing #200 Sieve DD = Dry Density (pcf)

Uc = Compressive Strength (tsf)

Location: See Boring Location Plan

Groundwater Data:

During drilling: Not encountered

Field Drilling Data:

Coordinates: Hand-held GPS Unit Logged By: CM Driller: Austin Geo-Logic Equipment: Truck-mounted drill rig

Coordinates: N30o32'9.17'' W97o50'52.35''

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B O

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K S

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-0

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R A

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-0

K

S L

.G L

B

UcDepth (ft)

Sample Type WC DDREC

RQD LL PI -200P, N

124 97

Boring Log No. B-2 (Lift Station 6)

GW

GP

GM

GC

SW

SP

SM

SC

ML

CL

MH

CH

Massive or Weakly Bedded Limestones

M o re t h a n h a lf o f m a te ri a l S

M A

L L E

R th a n N o S ie v e s iz e

F O

R M

A T

IO

N

A L

M A

T E

R

IA

L S

GROUP

SYMBOLS

KEY TO TERMS AND SYMBOLS USED ON BORING LOGS

C O

A R

S E

-G R

A

IN

E D

S O

IL

S

G R

A V

E L

S S

A N

D S

M o re t h a n H a lf o f C o a rs e f ra c ti o n i s

L A

R G

E R t h a n N o S ie v e s iz e

M o re t h a n h a lf o f m a te ri a l L A

R G

E R t h a n N o S ie v e s iz e

MAJOR DIVISIONS

Silty Gravels, Gravel-Sand-Silt Mixtures

Poorly-Graded Gravels, Gravel-Sand Mixtures, Little or no Fines

Well-Graded Gravels, Gravel-Sand Mixtures, Little or no Fines

DESCRIPTIONS

Clayey Sands, Sand-Clay Mixtures

Silty Sands, Sand-Silt Mixtures

Poorly-Graded Sands, Gravelly Sands, Little or no Fines

Well-Graded Sands, Gravelly Sands, Little or no Fines C le a n G ra v e ls

(l it tl e o r n o F in e s

G ra v e ls w h

F in

(A p p re c ia b le m o u n t o f F in e s

C le a n S a n d

(l tl e o r n o F in e s

S a n d s w it h F in

(A p p re c ia b le m o u n t o f F in e s

L iq u id

L im it l e th n

L iq u id

L im g re a te r th a n

LIMESTONE

MARLSTONE

SANDSTONE

Clayey Gravels, Gravel-Sand-Clay Mixtures

Massive Sandstones, Sandstones with Gravel Clasts

Inorganic Clays of High Plasticity, Fat Clays

Inorganic Silts, Micaceous or Diatomaceous Fine Sand or Silty Soils, Elastic Silts

Inorganic Clays of Low to Medium Plasticity, Gravelly Clays, Sandy Clays, Silty Clays, Lean Clays

Inorganic Silts & Very Fine Sands, Rock Flour, Silty or Clayey Fine Sands or Clayey Silts with Slight

Plasticity

Indurated Argillaceous Limestones

Indicates Final Observed Groundwater Level

Indicates Initial Observed Groundwater Location

Cretaceous Clay Deposits

Massive or Poorly Bedded Chalk Deposits

Mudstone or Massive Claystones

F

IN

E -G

R A

IN

E

D S

O

IL

S

M o re t h a n h a lf o f C o a rs e f ra c ti o n i

S M

A L L E

R t h a n N o S ie v e s iz e

S

IL

T

C

A Y

S

S

IL

T

C

A Y

S

GROUNDWATER

MARINE CLAYS

CHALK

CLAYSTONE

Very Dense

30 - 50

Over 50

10 - 30

Consistency and Strength of Cohesive Soils

Number of Blows per ft., N

Unconfined

Compressive

Strength, qᵤ (tsf)

Consistency

Density of Granular Soils

Relative Density

Very Loose

Number of

Blows per ft., N

0 - 4

4 - 10 Loose

Medium

Dense

Below 2

2 - 4 Soft

Very Soft

Stiff

Less than 0.25

0.25 - 0.5

0.5 - 1.0

1.0 - 2.0

Medium (Firm)

Very Stiff

Hard

4 - 8

8 - 15

15 - 30

Over 30 Over 4.0

2.0 - 4.0

Arias Geoprofessionals

Group

Symbol

GW

(Less than 5% fines C

Cu < 4 and/or GP

[Cc < 1 or Cc > 3] D

Gravels with Fines GM

(More than 12% fines C

GC

Sands Clean Sands SW

(Less than 5% fines H

) Cu < 6 and/or SP

[Cc < 1 or Cc > 3] D

Sands with Fines SM

(More than 12% fines H

SC

Silts and Clays inorganic CL

ML

organic OL

Silts and Clays inorganic CH

MH

organic OH

HIGHLY ORGANIC SOILS PT

A Based on the material passing the 3-inch (75mm) sieve B If field sample contained cobbles or boulders, or both, add "with cobbles or boulders, or both" to group name C Gravels with 5% to 12% fines require dual symbols:

GW-GM well-graded gravel with silt

GW-GC well-graded gravel with clay

GP-GM poorly-graded gravel with silt

GP-GC poorly-graded gravel with clay D

Cu = D60/D10 Cc =

E If soil contains ≥ 15% sand, add "with sand" to group name F If fines classify as CL-ML, use dual symbol GC-GM, or SC-SM G If fines are organic, add "with organic fines" to group name H Sand with 5% to 12% fines require dual symbols:

SW-SM well-graded sand with silt

SW-SC well-graded sand with clay

SP-SM poorly-graded sand with silt

SP-SC poorly-graded sand with clay I If soil contains ≥ 15% gravel, add "with gravel" to group name J If Atterberg limits plot in hatched area, soil is a CL-ML, silty clay K If soil contains 15% to < 30% plus No. 200, add "with sand" or "with gravel," whichever is predominant L If soil contains ≥ 30% plus No. 200, predominantly sand, add "sandy" to group name M If soil contains ≥ 30% plus No. 200, predominantly gravel, add "gravelly" to group name N PI ≥ 4 and plots on or above "A" line O PI < 4 or plots below "A" line P PI plots on or above "A" line Q PI plots below "A" line

TERMINOLOGY

Boulders Over 12-inches (300mm) Parting Inclusion < 1/8-inch thick extending through samples

Cobbles 12-inches to 3-inches (300mm to 75mm) Seam Inclusion 1/8-inch to 3-inches thick extending through sample

Gravel 3-inches to No. 4 sieve (75mm to 4.75mm) Layer Inclusion > 3-inches thick extending through sample

Sand No. 4 sieve to No. 200 sieve (4.75mm to 0.075mm)

Silt or Clay Passing No. 200 sieve (0.075mm)

Calcareous Containing appreciable quantities of calcium carbonate, generally nodular

Stratified Alternating layers of varying material or color with layers at least 6mm thick

Laminated Alternating layers of varying material or color with the layers less than 6mm thick

Fissured Breaks along definite planes of fracture with little resistance to fracturing

Slickensided Fracture planes appear polished or glossy sometimes striated

Blocky Cohesive soil that can be broken down into small angular lumps which resist further breakdown

Lensed Inclusion of small pockets of different soils, such as small lenses of sand scattered through a mass of clay

Homogeneous Same color and appearance throughout

(D30)

D10 x D60

KEY TO TERMS AND SYMBOLS USED ON BORING LOGS

TABLE 1 Soil Classification Chart (ASTM D 2487-11)

Group Name B

Organic Clay K,L,M,N

Organi Silt K,L,M,O

Fat Clay K,L,M

Clayey Gravel E,F,G

Well-Graded Sand I

Poorly-Graded Sand I

Silty Sand F,G,I

Clayey Sand F,G,I

Well-Graded Gravel E

Poorly-Graded Gravel E

Silty Gravel E,F,G

Soil Classification

Criteria of Assigning Group Symbols and Group Names Using Laboratory Tests A

More than 50% retained on No.

200 sieve

FINE-GRAINED SOILS

COARSE-GRAINED SOILS

Primarily organic matter, dark in color, and organic odor

Liquid limit less than 50

Liquid limit 50 or more

PI > 7 and plots on or above "A" line J

PI < 4 or plots below "A" line J

PI plots on or above "A" line

PI plots on or below "A" line

Fines classify as CL or

CH

(50% or more of coarse fraction passes No. 4 sieve)

50% or more passes the No.

200 sieve

Cu ≥ 4 and 1 ≤ Cc ≤ 3 DGravels Clean Gravels

Elastic Silt K,L,M

Organic Clay K,L,M,P

Organic Silt K,L,M,Q

Peat

Lean Clay K,L,M

Silt K,L,M

Fines classify as CL or

CH

Cu ≥ 6 and 1 ≤ Cc ≤ 3 D

Fines classify as ML or

MH

(More than 50% of coarse fraction retained on No. 4 sieve)

Fines classify as ML or

MH

<0.75

<0.75

Liquid limit - oven dried

Liquid limit - not dried

Liquid limit - oven dried

Liquid limit - not dried

Excellent

Rock Mass QualityVelocity IndexRQD %

90 – 100

75 – 90

50 – 75

25 – 50

0 – 25

0.80 – 1.00

0.60 – 0.80

0.40 – 0.60

0.20 – 0.40

0 – 0.20

Good

Fair

Very Poor

Poor

Very widely (fractured or jointed)

Widely

Medium

Closely

Very closely

Descriptions for Joints, Faults, or Other Fractures

Extremely close

Diagnostic Features

No visible sign of Decomposition or discoloration. Rings under hammer impact.

Slight discoloration inwards from open fractures, otherwise similar to F.

Discoloration throughout. Weaker minerals such as feldspar decomposed. Strength somewhat less than fresh rock, but cores cannot be broken by hand or scraped by knife. Texture preserved.

Most minerals somewhat decomposed. Specimens can be broken by hand with effort or shaved with knife. Core stones present in rock mass. Texture becoming indistinct, but fabric preserved.

Minerals decomposed to soil, but fabric and structure preserved (Saprolite). Specimens easily crumbled or penetrated.

Advanced state of decomposition resulting in plastic soils. Rock fabric and structure completely destroyed. Large volume change.

Spacing Description for Joints, Faults or Other Fractures

Thickly

Medium

Thinly

Very thinly

Description for Micro-Structural

Features: Lamination, Foliation, or

Cleavage

Intensely (laminated, foliated, or cleaved)

Very intensely

Spacing

¼ – ¾ inch

2 – 6 feet

Description for Structural Features:

Bedding, Foliation, or Flow Banding

Very thickly (bedded, foliated, or banded)

Symbol

F

WS

WM

WH

WC

RS

More than 6 feet

Engineering Classification for in Situ Rock Quality

Class

I

II

III

IV

V

Extremely hard

Hardness

Very hard

Hard

Soft

Very soft

Less than ¼ inch

¾ – 2½ inches

2½ – 8 inches

8 – 24 inches

Grade

Fresh

Slightly Weathered

Moderately Weathered

Highly Weathered

Completely Weathered

KEY TO TERMS AND SYMBOLS USED ON BORING LOGS

Hardness Classification of Intact Rock

Rock Weathering Classifications

Rock Discontinuity Spacing

Residual Soil

> 2,000

Approximate Range of Uniaxial

Compression Strength kg/cm²

(tons/ft²)

2,000 – 1,000

1,000 – 500

500 – 250

250 – 10

Field Test

Many blows with geologic hammer required to break intact specimen.

Hand held specimen breaks with hammer end of pick under more than one blow.

Cannot be scraped or pealed with knife, hand held specimen can be broken with single moderate blow with pick.

Can just be scraped or peeled with knife. Indentations 1mm to 3mm show in specimen with moderate blow with pick.

Material crumbles under moderate blow with sharp end of pick and can be peeled with a knife, but is too hard to hand-trim for triaxial test specimen.

FIELD EXPLORATION PROCEDURES

The field exploration program included drilling at selected locations within the site and intermittently sampling the encountered materials. The boreholes were drilled using single flight auger (ASTM D 1452). Samples of encountered materials were obtained using a Standard

Penetration Test (ASTM D1586) or seamless steel push-tubes for obtaining samples of cohesive strata (ASTM D1587). Rotary rock coring was performed in general accordance with ASTM

D2113. The sample depth interval and type of sampler used is included on the soil boring log.

Arias’ field representative visually logged each recovered sample and placed a portion of the recovered sampled into a plastic bag for transport to our laboratory.

SPT N values and blow counts for those intervals where the sampler could not be advanced for the required 18-inch penetration are shown on the soil boring log. If the test was terminated during the 6-inch seating interval or after 10 hammer blows were applied used and no advancement of the sampler was noted, the log denotes this condition as blow count during seating penetration. Penetrometer readings recorded for thin-walled tube samples that remained intact also are shown on the soil boring log.

APPENDIX C: LABORATORY DATA AND TEST PROCEDURES

0 20 40 60 80 100

B-01

B-01

B-01

B-02

B-02

ML

CL

MH

CH

CL-ML

P L A S T I C I T Y

I N D E X

LIQUID LIMIT

Fines ClassificationBoring

FAT CLAY (CH)

SANDY FAT CLAY with GRAVEL (CH)

LEAN CLAY with SAND (CL)

FAT CLAY with SAND (CH)

FAT CLAY (CH)

LL PL PI

2.0

6.0

8.0

0.0

2.0

ATTERBERG LIMITS RESULTS

Depth

Project: Leander Lift Station Improvements

Location: See Boring Location Plan

Job No.: 2021-1440

-1

0.

G

P J

2/ 8/

A T

T E

R B

E R

G L

IM

IT

S S

U M

M A

R Y

G R

A P

H ,U

S _L

A B

.G D

T ,L

IB

R

A R

Y

-0

K S

L.

G

LB

Arias & Associates 13581 Pond Springs Rd #210 Austin, TX 78729 Phone: 512.428.5550 Fax: 512.428.5525

0.0010.010.1110100

Cc

HYDROMETERU.S. SIEVE OPENING IN INCHES U.S. SIEVE NUMBERS

D100 D60

CuLL PL

GRAIN SIZE IN MILLIMETERS

P E

R C

E N

T F

IN

E

R B

Y W

E

IG

H T coarse

%Gravel %Sand %Silt %Clay

100 1403 2

Depth

1.5 medium

6 810 14

Classification

503/4 1/23/8

Boring

Boring Depth

GRAIN SIZE DISTRIBUTION

COBBLES

GRAVEL SAND

PI

D10 fine

Arias Geoprofessionals coarse

SILT OR CLAY

D30

B-01

B-01

B-01

B-02

20016 20 30 4016 60 fine

B-01

B-01

B-01

B-02

FAT CLAY (CH)

SANDY FAT CLAY with GRAVEL (CH)

LEAN CLAY with SAND (CL)

FAT CLAY with SAND (CH)

96.0

66.0

74.0

84.0

Silt and clay fractions were determined using 0.002 mm as the maximum particle size for clay.

2.0

6.0

8.0

0.0

4.75

4.0

18.0

24.0

8.0

0.0

16.0

2.0

8.0

2.0

6.0

8.0

0.0

Elev

Project: Leander Lift Station Improvements

Location: See Boring Location Plan

Job No.: 2021-1440

-1

0.

G

P J

2/ 8/

G R

A

IN

S

IZ

E A

R

IA

S ,U

S _L

A B

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A R

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-0

K S

L.

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LB

Arias & Associates 13581 Pond Springs Rd #210 Austin, TX 78729

0.0010.010.1110100

Cc

HYDROMETERU.S. SIEVE OPENING IN INCHES U.S. SIEVE NUMBERS

D100 D60

CuLL PL

GRAIN SIZE IN MILLIMETERS

P E

R C

E N

T F

IN

E

R B

Y W

E

IG

H T coarse

%Gravel %Sand %Silt %Clay

100 1403 2

Depth

1.5 medium

6 810 14

Classification

503/4 1/23/8

Boring

Boring Depth

GRAIN SIZE DISTRIBUTION

COBBLES

GRAVEL SAND

PI

D10 fine

Arias Geoprofessionals coarse

SILT OR CLAY

D30

B-02

20016 20 30 4016 60 fine

B-02 FAT CLAY (CH) 71 33 38

98.0

Silt and clay fractions were determined using 0.002 mm as the maximum particle size for clay.

2.0 4.75 2.00.0

2.0

Elev

Project: Leander Lift Station Improvements

Location: See Boring Location Plan

Job No.: 2021-1440

-1

0.

G

P J

2/ 8/

G R

A

IN

S

IZ

E A

R

IA

S ,U

S _L

A B

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T ,L

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A R

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K S

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LB

Arias & Associates 13581 Pond Springs Rd #210 Austin, TX 78729

LABORATORY TEST PROCEDURES

Arias performed soil mechanics laboratory tests on selected samples to aid in soil classification and to determine engineering properties. Tests commonly used in geotechnical exploration, the method used to perform the test, and the column designation on the boring log where data are reported are summarized as follows:

Test Name Test Method Log Designation

Water (moisture) content of soil and rock by mass ASTM D 2216 WC

Liquid limit, plastic limit, and plasticity index of soils ASTM D 4318 PL, LL, PI

Amount of material in soils finer than the No. 200 sieve ASTM D 1140 -200

Unconfined compressive strength of rock ASTM D 7012 Uc

The laboratory results are reported on the soil boring logs.

APPENDIX D: GBA INFORMATION

Geotechnical-Engineering Report Important Information about This

Subsurface problems are a principal cause of construction delays, cost overruns, claims, and disputes.

While you cannot eliminate all such risks, you can manage them. The following information is provided to help.

The Geoprofessional Business Association (GBA) has prepared this advisory to help you – assumedly a client representative – interpret and apply this geotechnical-engineering report as effectively as possible. In that way, clients can benefit from a lowered exposure to the subsurface problems that, for decades, have been a principal cause of construction delays, cost overruns, claims, and disputes. If you have questions or want more information about any of the issues discussed below, contact your GBA-member geotechnical engineer.

Active involvement in the Geoprofessional Business Association exposes geotechnical engineers to a wide array of risk-confrontation techniques that can be of genuine benefit for everyone involved with a construction project.

Geotechnical-Engineering Services Are Performed for Specific Purposes, Persons, and Projects Geotechnical engineers structure their services to meet the specific needs of their clients. A geotechnical-engineering study conducted for a given civil engineer will not likely meet the needs of a civil-works constructor or even a different civil engineer. Because each geotechnical-engineering study is unique, each geotechnical-engineering report is unique, prepared solely for the client. Those who rely on a geotechnical-engineering report prepared for a different client can be seriously misled. No one except authorized client representatives should rely on this geotechnical-engineering report without first conferring with the geotechnical engineer who prepared it. And no one

– not even you – should apply this report for any purpose or project except the one originally contemplated.

Read this Report in Full Costly problems have occurred because those relying on a geotechnical-engineering report did not read it in its entirety. Do not rely on an executive summary. Do not read selected elements only. Read this report in full.

You Need to Inform Your Geotechnical Engineer about Change Your geotechnical engineer considered unique, project-specific factors when designing the study behind this report and developing the confirmation-dependent recommendations the report conveys. A few typical factors include:

• the client’s goals, objectives, budget, schedule, and risk-management preferences;

• the general nature of the structure involved, its size, configuration, and performance criteria;

• the structure’s location and orientation on the site; and

• other planned or existing site improvements, such as retaining walls, access roads, parking lots, and underground utilities.

Typical changes that could erode the reliability of this report include those that affect:

• the site’s size or shape;

• the function of the proposed structure, as when it’s changed from a parking garage to an office building, or from a light-industrial plant to a refrigerated warehouse;

• the elevation, configuration, location, orientation, or weight of the proposed structure;

• the composition of the design team; or

• project ownership.

As a general rule, always inform your geotechnical engineer of project changes – even minor ones – and request an assessment of their impact.