GEOTECHNICAL ENGINEERING REPORT

PROPOSED LIBERTY HILL CITY PARK- PARKING LOT

255 County Road 200

Liberty Hill, Texas UES Project No. Y252041

June 25, 2025

PREPARED FOR:

KIMLEY HORN AND ASSOCIATES

5301 Southwest Parkway, Building 2, Suite 100

Austin, Texas, 78735 Attention: Austin Powers

Prepared by:

UES

7 Roundville Lane

Round Rock, Texas 78664 512-284-8022| TeamUES.com

TBPELS Firm No. 2101

7 Roundville Lane, Round Rock, Texas 78664 512 284 8022 | TeamUES.com

June 25, 2025

Kimley Horn And Associates 5301 Southwest Parkway, Building 2, Suite 100 Austin, Texas, 78735

Attention: Austin Powers

Re: Geotechnical Engineering Report Proposed Liberty Hill City Park- Parking Lot 255 County Road 200 Liberty Hill, Texas UES Project No. Y252041

Kimley Horn And Associates:

UES has performed a geotechnical exploration for the project referenced above. This study was authorized by Sean Mason (Associate) with Kimley Horn and Associates, Inc and performed in accordance with UES Proposal No.110746 dated February 14, 2025, and Kimley Horn individual project order number 069415802.1.002

The results of this exploration, together with our recommendations, are presented in the accompanying report, an electronic copy of which is being transmitted herewith.

UES appreciates the opportunity to be of service on this project. If we can be of further assistance, such as providing materials testing services during construction, please contact our office.

Sincerely, Mostafa Bahmani, Ph.D., P. E.

Geotechnical Engineer

Ivan Jimenez Geotechnical Project Manager

UES

TBPELS Firm No. 2101

1.0 INTRODUCTION

2.0 SITE CONDITIONS

3.0 FIELD EXPLORATION

4.0 SUBSURFACE CONDITIONS

4.1 Geology

4.2 Subsurface Lithology

4.3 Groundwater Observations

4.4 Seismic Site Classification

5.0 LABORATORY TESTING

6.0 RECOMMENDATIONS

6.1 Potential Movement of Expansive Soil

6.2 Earthwork

6.2.1 Excavation Safety Considerations

6.2.2 Site Preparation and Proofroll

6.2.3 Construction Considerations

6.2.4 Grading, Drainage and Other Considerations

6.2.5 Groundwater Control

6.2.6 Fill Compaction

6.2.7 Utilities

6.3 Pavement

6.3.1 Pavement Subgrade

6.3.2 Rigid Pavements

6.3.3 Flexible Pavements

7.0 LIMITATIONS/GENERAL COMMENTS

TABLE OF CONTENTS

APPENDICES

APPENDIX A

APPENDIX B

APPENDIX C

Geotechnical Engineering Report Proposed Liberty Hill City Park- Parking Lot, 255 County Road 200

UES Project No. Y252041 June 25, 2025

1.0 INTRODUCTION

Purpose and Scope. The purpose of this geotechnical study was to evaluate some of the physical and engineering properties of the subsurface materials at selected locations on the subject site to develop geotechnical engineering design parameters and recommendations for the proposed project. To accomplish this, the scope of this study included field exploration consisting of drilling test borings and collecting samples of the subsurface materials, performing laboratory testing on selected samples obtained during the field exploration, performing engineering analysis and evaluation of the subsurface conditions with respect to the project characteristics, and development of geotechnical recommendations suitable for the proposed project. The scope of services did not include an environmental assessment of the site.

Limitations. Recommendations provided in this report were developed from information obtained in test borings depicting subsurface conditions only at the specific test boring locations and at the time designated on the logs. Subsurface conditions at other locations may differ from those observed at the test boring locations, and subsurface conditions at boring locations may vary at different times of the year. The scope of work may not fully define the variability of subsurface materials and conditions that are present on the site.

The nature and extent of variations between borings may not become evident until construction. If significant variations then appear evident, our office should be contacted to re-evaluate our recommendations after performing on-site observations and possibly other tests.

Project Location. The project is located at 255 County Road 200 in Liberty Hill, Texas.

Project Description. Based on the available information provided, UES understands the project will consist of proposed improvements to the existing parking lot, which will include paved parking and driveway areas.

Site Grading. A site grading plan was not available at the time of writing this report. Our recommendations provided herein are on the basis that cuts and fills of less than 1 foot will be required to bring the site to grade. When the site grading plan is available, we should be notified and allowed to review the site grading plan to assess and modify our recommendations, as necessary.

2.0 SITE CONDITIONS

Review of Aerial Images. Review of aerial images available from Google Earth™ indicated the site had an existing gravel pavement road. Due to the intermittent nature and relatively low resolution of aerial photographs, as well as the lack of provided information regarding the past land use of the site, our review should not be interpreted as eliminating the possibility of past activities on site which could detrimentally affect

Proposed Liberty Hill City Park- Parking Lot, 255 County Road 200

UES Project No. Y252041 June 25, 2025 future construction. No additional information was provided for this study regarding previous site activities or development.

3.0 FIELD EXPLORATION

Test Borings. The field exploration for this project included performing a total of seven

(7) test borings as summarized in the following table. Boring depths were measured from the existing ground surface at the respective boring location at time of the field exploration.

Summary of Boring Depths and Locations Boring

Identification Depth, feet Location

B-1 to B-7 10 Paving Area

Test borings were advanced using standard rotary drilling equipment at the approximate locations as shown in. Appendix A Boring Location Plan. The boring locations were not surveyed. UES located the test borings in the field using a hand-held GPS unit with lateral accuracy of ± 20 ft. Therefore, the test boring locations should be considered approximate.

Relatively Undisturbed Soil Sampling. Cohesive soil samples were generally obtained using Shelby tube samplers in general accordance with ASTM D1587. The Shelby tube sampler consists of a thin- or thick-walled steel tube with a sharp cutting edge connected to a head equipped with a ball valve threaded for rod connection. The tube is pushed into the undisturbed soils by the hydraulic pulldown of the drilling rig. The soil specimens were extruded from the tube in the field, logged, and tested for consistency using a hand penetrometer, sealed and packaged to maintain "in situ" moisture content. The consistency of relatively undisturbed soil samples was evaluated in the field using a calibrated hand penetrometer. In this test a 0.25-inch diameter piston is pushed into the undisturbed sample at a constant rate to a depth of 0.25-inch. The results of these tests are tabulated at the respective sample depths on the test boring logs. When the capacity of the penetrometer is exceeded, the value is tabulated as 4.5+. One representative portion of each sample was sealed in a plastic bag for use in future visual evaluation and possible testing in the laboratory.

Disturbed Soil Sampling. Disturbed soil samples were generally obtained using split-spoon barrel sampling procedures in general accordance with ASTM D1586. In the split-spoon barrel procedure, a disturbed sample is obtained in a standard 2-inch outside diameter (OD) split barrel sampling spoon driven 18 inches into the ground using a 140-pound (lb) hammer falling freely 30 inches. The number of blows for the last 12 inches of a standard 18-inch penetration is recorded as the Standard Penetration Test resistance (N-value). The N-values are recorded on the boring logs at the depth of sampling.

Samples were sealed and returned to the laboratory for further evaluation and possible testing.

Proposed Liberty Hill City Park- Parking Lot, 255 County Road 200

Groundwater Observations. A summary of groundwater observations is provided in Section 4.3.

Borehole Backfilling and Plugging. Upon completion of the test borings, the boreholes were backfilled with on-site soil cuttings, and the surface was plugged using bentonite hole plug.

4.0 SUBSURFACE CONDITIONS

4.1 Geology

Geologic Formation. Based on our experience and a review of the Geologic Atlas of Texas Austin Sheet (1981), the project site appears to be located within the Glen Rose Limestone Formation near the Walnut Clay Formation. The Glen Rose Limestone Formation consists of limestone, clay, and some sandstone forming a characteristic stairstep topography. The limestone can be fine-grained, silty with some occasionally dolostone with chalky hard textures and nodular surfaces. Sand beds are thin while the clay and claystone can be sandy to marly and typically recessive. Colors can vary from brown and yellow to gray. The Walnut Clay Formation consists of clay, shale, and limestone. It can be chalky, marly with hard beds of sparry calcite, and thin beds of shale most common in the upper parts with thickness ranging from 125 to 175 feet.

4.2 Subsurface Lithology

Stratigraphy. Descriptions of the various strata and their approximate depths and thickness per the Unified Soil Classification System (USCS) are provided on the boring logs included in Appendix B- Boring Logs. Terms and symbols used in the USCS are presented in Appendix C following the Boring Logs. Subsurface material encountered are described in the following table:

Proposed Liberty Hill City Park- Parking Lot, 255 County Road 200

UES Project No. Y252041 June 25, 2025

Generalized Subsurface Conditions at Proposed Pavement Location (Test Boring B-01 to B-07)

Nominal Depth, feet General Description

Detailed Description of Soils/Materials Encountered Top of

Layer Bottom of

Layer

0 to 4½ 6½ to 10 CLAEY GRAVEL Very stiff to hard CLAYEY GRAVEL (GC)

0 to 6½ 10 CLAY Hard GRAVELLY LEAN CLAY (CL) Very stiff to hard SANDY LEAN CLAY (CL)

0 4½ to 10 CLAYEY SAND Very stiff to hard CLAYEY SAND (SC)

Depths referenced in this report are measured from the existing ground surface at the respective test boring location at time of the field exploration.

It should be noted that the depths provided in the boring logs are based on our Field Technician’s and Engineer’s interpretation of conditions believed to exist between actual samples retrieved. Therefore, information on the boring logs contains both factual and interpretive information. Lines delineating subsurface strata are approximate and the actual transition between strata may be gradual or not clearly defined. In addition, variations may occur between or beyond the boring locations.

4.3 Groundwater Observations

Groundwater Levels. Groundwater levels were not encountered in the test borings during this study. Depths referenced in this report are measured from the existing ground surface at the respective boring location at time of the field exploration.

Long-term Groundwater Monitoring. Groundwater observations in this report are those that were present at the time the test borings were drilled. The depth and amount of water encountered in an open borehole largely depends on the permeability of the soils encountered at the test boring locations. In relatively impervious soils, such as clayey soils, a suitable estimate of the groundwater depths generally requires long-term monitoring. Long-term monitoring of groundwater conditions via piezometers or groundwater monitoring wells were not performed during this study and were beyond the scope of this study. Long-term monitoring can reveal groundwater levels materially different than those measured in the borings.

Groundwater Fluctuations. Subsurface groundwater fluctuations can occur. Future construction activities can alter the surface and subsurface drainage characteristics of this site. Seasonal variations, temperature, land-use, proximity to water bodies, and rainfall can also influence groundwater levels. UES recommends that the contractor

Proposed Liberty Hill City Park- Parking Lot, 255 County Road 200

UES Project No. Y252041 June 25, 2025 verifies the groundwater elevation before construction starts.

4.4 Seismic Site Classification

The Site Class assigned for seismic design considers various factors, such as the soil profile (whether it's soil or rock), shear wave velocity, and strength, averaged over a depth of 100 feet. Since the borings didn't reach depths of 100 feet, UES made determinations under the assumption that the subsurface materials beneath the borehole bottoms resembled those encountered at the termination depth. Following the guidelines outlined in Section 1613.2.2 of the 2024 International Building Code and Table 20.2-1 in the 2022 ASCE-7, UES recommends using Site Class C (very dense soil and soft rock) for seismic design purposes at this location.

5.0 LABORATORY TESTING

UES performs visual classification and laboratory tests, as appropriate, to define pertinent engineering characteristics of the soils encountered. Laboratory tests are performed in general accordance with ASTM or other applicable standards. Test results are included at the respective sample depths on the boring logs or separately tabulated herewith, as appropriate, Laboratory tests and procedures performed for this geotechnical study are summarized in the following table.

Summary of Laboratory Tests and Procedures

Test Procedure Description ASTM D4220 Standard Practices for Preserving and Transporting Soil Samples

ASTM D2487 Standard Classification of Soils for Engineering Purposes (Unified Soil Classification System)

ASTM D2488 Standard Practice for Description and Identification of Soils (Visual-Manual Procedure)

ASTM D2216 Standard Test Method for Laboratory Determination of Water (Moisture) Content of Soil and Rock by Mass

ASTM D4318 Standard Test Methods for Liquid Limit, Plastic Limit, and Plasticity Index of Soils

ASTM D1140 Standard Test Methods for Amount of Material in Soils Finer than the No. 200 (75-μm) Sieve

6.0 RECOMMENDATIONS

6.1 Potential Movement of Expansive Soil

Estimated Potential Movement. Our findings indicated within existing grade could experience post construction movements of about 2 to 2½ inches due to shrinking and swelling of expansive soils (active clays). For the purpose of this report, movement due

Proposed Liberty Hill City Park- Parking Lot, 255 County Road 200 to shrinking and swelling of active clays will be referred to as potential vertical movement

(PVR).

Method of Estimation. PVR is estimated in general accordance with methods outlined by Texas Department of Transportation (TxDOT) Test Method Tex-124-E., and engineering judgment and experience. Estimated PVR calculated assuming the moisture content of the in-situ soil within the normal zone of seasonal moisture content change varies between as defined by Tex-124-E. Also, it was assumed that a 1 psi surcharge load from the floor slab acts on the subgrade soils. Movements exceeding our estimates could occur if positive drainage of surface water is not maintained or if soils are subject to an outside water source, such as leakage from a utility line or subsurface moisture migration from off-site locations.

Assumptions. PVR was estimated based on the assumption that any fill used to raise the grade consists of onsite or similar soil with a plasticity index (PI) of 35 or less. The use of fill material with a PI greater than 35 could result in potential movements exceeding our estimates.

6.2 Earthwork

Variations in subsurface conditions could be encountered during construction. To permit correlation between test boring data and actual subsurface conditions encountered during construction, it is recommended a registered Professional Engineering firm be retained to observe construction procedures and materials.

Some construction problems, particularly degree or magnitude, cannot be reasonably anticipated until the course of construction. The recommendations offered in the following paragraphs are intended not to limit or preclude other conceivable solutions, but rather to provide our observations based on our experience and understanding of the project characteristics and subsurface conditions encountered in the borings.

6.2.1 Excavation Safety Considerations

Excavation Safety. The contractor is responsible for designing any excavation slopes, temporary sheeting or shoring. Design of these structures should include any imposed surface surcharges. Construction site safety is the sole responsibility of the contractor, who shall also be solely responsible for the means, methods and sequencing of construction operations. The contractor should also be aware that slope height, slope inclination or excavation depths (including utility trench excavations) should in no case exceed those specified in local, state and/or federal safety regulations, such as OSHA Health and Safety Standard for Excavations, 29 CFR Part 1926, or successor regulations.

Stockpiles should be placed well away from the edge of the excavation and their heights should be controlled so they do not surcharge the sides of the excavation. Surface drainage should be carefully controlled to prevent flow of water over the slopes and/or into the excavations. Construction slopes should be closely observed for signs of mass

Proposed Liberty Hill City Park- Parking Lot, 255 County Road 200 movement, including tension cracks near the crest or bulging at the toe. If potential stability problems are observed, a geotechnical engineer should be contacted immediately. Shoring, bracing or underpinning required for the project (if any) should be designed by a professional engineer registered in the State of Texas.

6.2.2 Site Preparation and Proofroll

Site Clearing. In the area of improvements, all concrete, trees, stumps, brush, debris, septic tanks, abandoned structures, roots, vegetation, rubbish and any other undesirable matter should be removed and properly disposed.

Proofroll. Paving areas subgrades should be proofrolled in accordance with TX-DOT Specification Item 216 with a fully loaded tandem axle dump truck or similar pneumatic-tire equipment weighing at least 25 tons to locate areas of loose subgrade. In areas to be cut, the proofroll should be performed after the final grade is established. In areas to be filled, the proofroll should be performed prior to fill placement. Areas of loose or soft subgrade encountered in the proofroll should be removed and replaced with engineered fill, (dried or wetted, as needed) and compacted in place. Prior to placement of any fill, the exposed soil subgrade should then be scarified to a minimum depth of 6 inches and recompacted as outlined in Section 6.4.6.

6.2.3 Construction Considerations

Surface Sandier/Siltier Soils. The sandier/siltier soils encountered at and near the ground surface at this site are very susceptible to changes in moisture. The presence of surface water due to precipitation or groundwater may result in a decrease in the ability to compact and work with the soil. It is common for these soils to pump when subjected to high levels of moisture. In addition, these soils located at and near the ground surface will allow surface water to infiltrate until the water becomes perched on a less permeable layer at depth. As such, construction difficulties should be anticipated, especially during the wet season or immediately after rain events. Although having a thin layer of non-plastic or low plasticity soils overlying cohesive soils is typical of this geologic region, our experience suggests that the local contractors find these materials troublesome and can often be the source of change orders, construction delays, and budget over runs. Soils of this type are especially prone to requiring the implementation of wet weather/soft subgrade recommendations provided in this report.

Maintenance of Subgrade during Construction. While the exposed subgrade is expected to remain relatively stable initially, unstable conditions may arise during general construction activities, particularly if the soil is exposed to wet weather conditions and repetitive construction traffic. The use of lighter construction equipment can help minimize disturbance to the subgrade. In the event of unstable conditions, stabilization measures will be necessary. After grading is completed, it's crucial to maintain the moisture content of the subgrade before proceeding with pavement construction.

Minimizing construction traffic over the finished subgrade is advisable. If the subgrade becomes frozen, desiccated, saturated, or disturbed, the affected material should either

Proposed Liberty Hill City Park- Parking Lot, 255 County Road 200 be removed or treated by scarification, moisture conditioning, and recompaction before pavement construction begins. UES should be retained to observe earthwork and to perform necessary tests and observations during subgrade preparation.

Wet Weather/Soft Subgrade. Soft and/or wet surface soils may be encountered during construction, especially following periods of wet weather. Wet or soft surface soils can present difficulties for compaction and other construction equipment. If specified compaction cannot be achieved due to soft or wet surface soils, one of the following corrective measures will be required:

1. Removal of the wet and/or soft soil and replacement with select fill,

2. Chemical treatment of the wet and/or soft soil with Lime-fly ash or cement to improve the subgrade stability, or

3. If allowed by the schedule, drying by natural means.

Chemical treatment is usually the most effective way to improve soft and/or wet surface soils. UES should be contacted for additional recommendations if chemical treatment is planned due to wet and/or soft soils.

Fill on Existing Slopes. If fill is to be placed on existing slopes (natural or constructed) steeper than six horizontal to one vertical (6:1), the fill materials should be benched into the existing slopes in such a manner as to provide a minimum bench-key width of five (5)

ft. This should provide a good contact between the existing soils and new fill materials, reduce potential sliding planes, and allow relatively horizontal lift placements.

6.2.4 Grading, Drainage and Other Considerations

Efforts should be made to minimize the excessive wetting or drying of the underlying soil, as it can lead to swelling and shrinkage of these soil layers. Standard construction practices of providing good surface water drainage should be used. A positive slope of the ground away from any pavement subgrade should be provided. Ditches or swales should be provided to carry the run-off water both during and after construction.

Stormwater runoff should be collected by gutters and downspouts and should discharge away from the buildings.

In areas with pavement or sidewalks adjacent to the structure, a positive seal must be maintained between the structure and the pavement or sidewalk to minimize seepage of water into the underlying supporting soils. Post-construction movement of pavement and flatwork is common. Normal maintenance should include inspection of all joints in paving and sidewalks, etc. as well as re-sealing where necessary.

Since granular bedding backfill is used for most utility lines, the backfilled trench should not become a conduit and allow access for surface or subsurface water to travel toward the new structures. Concrete cut-off collars or clay plugs should be provided where utility lines cross pavement lines to prevent water from traveling in the trench backfill and entering beneath the structures.

Proposed Liberty Hill City Park- Parking Lot, 255 County Road 200

Root systems from trees and shrubs can draw a substantial amount of water from the clay soils at this site, causing the clays to dry and shrink in excess of our estimates. This could cause settlement beneath grade-supported slabs such as floors, walks and paving.

Trees and large bushes should be located a distance equal to at least one-half their anticipated mature height away from grade slabs. Lawn areas should be watered moderately, without allowing the clay soils to become too dry or too wet.

6.2.5 Groundwater Control

Groundwater was not encountered during drilling. However, from our experience, shallower groundwater seepage could be encountered in excavations for foundations, utilities and other general excavations at this site. The risk of seepage increases with depth of excavation and during or after periods of precipitation. The risk of seepage is also increased where limestone is exposed in excavations and slopes or is near final grade. Standard sump pits and pumping may be adequate to control seepage on a local basis.

If groundwater is encountered during excavation, dewatering to bring the groundwater below the bottom of excavations may be required. Dewatering could consist of standard sump pits and pumping procedures, which may be adequate to control seepage on a local basis during excavation. Supplemental dewatering will be required in areas where standard sump pits and pumping is not effective. Supplemental dewatering could include submersible pumps in slotted casings, well points, or eductors. For supplemental dewatering, the contractor should submit a groundwater control plan, prepared by a licensed engineer experienced in that type of work.

6.2.6 Fill Compaction

Select Fill. Select fill used as non-expansive fill should consist of soil with a liquid limit of 35 or less and a Plasticity Index between 7 and 20. The select fill should be placed in loose lifts not exceeding 8-inches and should be compacted to at least 95 percent maximum dry density (per ASTM D-698) at a moisture content between optimum and 4 percent above optimum moisture content. The plasticity index and liquid limit of material used as select non-expansive material should be routinely verified during placement using laboratory tests. Visual observation and classification should not be relied upon to confirm the material to be used as select, non-expansive material satisfies the required Atterberg-limit criteria.

Lime-treated Clay. Based on the laboratory testing conducted for this study, the native clay on-site soils will not meet requirements for select fill outlined in the section titled “Fill”.

As an alternative to importing select fill, the native clay soil may be blended with lime to reduce the plasticity index to meet select fill requirements. Based on our experience, we expect that it will require between 4 and 9 percent lime (by dry unit weight) to reduce the plasticity index of the native clay soils to select fill requirements. Lime series tests should be performed to assess the amount of lime required. Soluble sulfate tests should also be performed on the clay materials proposed for lime treatment prior to conducting lime

Proposed Liberty Hill City Park- Parking Lot, 255 County Road 200 treatment.

Flexible Base Material. Flexible base material used as non-expansive material in the pavement pad should consist of material meeting the requirements of TxDOT Standard Specifications Item 247, Type A or D, Grade 1-2 or 3. The flexible base should be compacted to at least 98 percent of standard Proctor maximum dry density (ASTM D 698) and within the range of 2 percentage points below to 2 percentage points above the material's optimum moisture content.

Processed Rock. Processed rock or rock-like materials (i.e. processed concrete and brick) used as fill should be compacted to at least 95 percent of standard Proctor maximum dry density, at a moisture content of 0 to 4 percentage points above optimum moisture. Individual rock pieces larger than 6 inches in dimension should not be used as fill. However, if rock fill is utilized within 3 ft below the bottom of floor slabs, the maximum allowable size of individual rock pieces should be reduced to 3 inches. Limestone used as fill should incorporate sufficient fines to prevent the presence of voids around larger diameter rock pieces. A gradation of at least 40 percent passing a standard No. 4 sieve is recommended.

General Fill. General fill may be placed in improved areas outside of pavement pad areas.

General fill should consist of material approved by the Geotechnical Engineer with a liquid limit less than 50. General fill should be placed in loose lifts not exceeding 8 inches and should be uniformly compacted to a minimum of 95 percent maximum dry density (per ASTM D-698) and within ±2 percent of the optimum moisture content. The subgrade to receive general fill should be scarified to a depth of 6 inches and compacted to at least 95 percent maximum dry density (per ASTM D-698) and at a moisture content between optimum and 4 percent above optimum moisture content.

Fill Restrictions. Non-Expansive fill and general fill should consist of those materials meeting the requirements stated. Fill soils should not contain material greater than 4 inches in any direction, debris, vegetation, waste material, environmentally contaminated material, or any other unsuitable material.

Fill Compaction Testing Guidelines. Field compaction and classification tests should be performed by UES. Compaction tests should be performed in each lift of the compacted material. If the materials fail to meet the density or moisture content specified, the course should be reworked as necessary to obtain the specified compaction. Classification confirmation inspection/testing should be performed daily on select fill materials (whether on-site or imported) to confirm consistency with the project requirements. The testing frequency recommended herein can be altered (increased or decreased) at the discretion of the geotechnical engineer of record.

Liability Limitations. Since proper field inspection and testing are critical to the design recommendations provided herein, UES cannot assume responsibility or liability for recommendations provided in this report if construction inspection and/or testing is performed by another party.

Proposed Liberty Hill City Park- Parking Lot, 255 County Road 200

6.2.7 Utilities

Bedding. Pipe bedding and pipe-zone backfill for underground utilities should meet the requirements of the pipe manufacturer. If no manufacturer requirement exists, then pipe bedding should be placed in accordance with applicable municipal or TxDOT requirements. Unless specified otherwise, the pipe-zone generally consists of all materials surrounding the pipe in the trench from six (6) inches below the pipe to 12 inches above the pipe. Since granular bedding backfill is used for most utility lines, the backfilled trench should not become a conduit and allow access for surface or subsurface water to travel toward the new structure. Concrete cut-off collars or clay plugs should be provided where utility lines cross pavement lines to prevent water from traveling in the trench backfill and entering beneath the structure. At least 1 ft of soil cover should exist between concrete plugs and structural elements. Local municipality or jurisdiction take precedence over pipe bedding recommendations herein.

Backfill. The trench backfill for utilities should be properly placed and compacted as outlined in Section 6.4.6 and in accordance with requirements of local City standards.

Utility backfill in the pavement areas should be placed in accordance with applicable requirements for the pavement areas.

Trench Settlement. Even if fill is properly compacted, fills in excess of about 10 ft are still subject to settlements over time of up to about 1 to 2 percent of the total fill thickness.

This should be considered when designing pavement over utility lines and/or other areas with deep fill. Where utility lines are deeper than 10 ft, the fill/backfill below 10 ft should be compacted to at least 100 percent of standard Proctor maximum dry density (ASTM D 698) and within –2 to +2 percentage points of the material's optimum moisture content.

The portion of the fill/backfill shallower than 10 ft should be compacted as previously outlined. Density tests should be performed on each lift (maximum 12-inch thick) and should be performed as the trench is backfilled. Local municipality or jurisdiction take precedence over trench backfill recommendations herein.

Trench Excavation. If utility trenches or other excavations extend to a depth of 5 ft or more below construction grade, the contractor or others shall be required to develop an excavation safety plan to protect personnel entering the excavation or excavation vicinity.

The collection of specific geotechnical data and the development of such a plan, which could include designs for sloping and benching or various types of temporary shoring, is beyond the scope of this study. Any such designs and safety plans shall be developed in accordance with current OSHA guidelines and other applicable industry standards.

6.3 Pavement

General. Recommendations for rigid and flexible pavement and preparation of the pavement subgrade are provided in the following sections. A traffic study indicating the number and type of vehicles on which to base the pavement design was not provided.

Proposed Liberty Hill City Park- Parking Lot, 255 County Road 200

Therefore, our recommendations are based upon our experience with similar projects assuming normal vehicular loading. Any unusual loading conditions (e.g., heavy forklifts) should be brought to our attention prior to finalizing the pavement design so that we may assess and modify our recommendations as necessary.

Civil and Drainage Consideration. Pavement design is the responsibility of the project Civil Engineer. We have recommended preliminary pavement sections based on geotechnical information and assumed/available traffic information in accordance with the American Association of State Highway and Transportation Officials (AASHTO) Guidelines for Design of Pavement Structures dated 1993. According to AASHTO design methodology, the pavement design thickness considers pavement performance, traffic, subgrade soils, pavement materials, environment, drainage and reliability. The applicability of our assumptions should be reviewed and approved by the project Civil Engineer before the pavement section is finalized. The recommended pavement sections assume good drainage quality prevails over the life of the pavement and that the pavement subgrade is exposed to moisture levels approaching saturation less than 25 percent of the time. Good drainage is defined by AASHTO as "the ability to remove water from the pavement within one (1) day”. Therefore, it is critical that the project Civil Engineer provide appropriate pavement drainage design to assure validity of the assumed drainage conditions.

6.3.1 Pavement Subgrade

Potential Vertical Soil Movements. We have assumed that site treatment will not be performed within the pavement areas for this project. As a result, pavements will be subjected to the calculated PVR for this site. Based on the information gathered during this study, a pavement constructed on-grade will be subject to potential vertical movements of up to 2 to 2½-inches. Because heave is generally associated with a source of water, it can occur differentially. Edge lift, excessive cracking, corner breaks, and poor ride quality are just a few of the many examples of pavement issues that can occur when in-situ PVR values are high. We should be contacted to provide PVR mitigation strategies to help reduce potential movements if desired. structural distress and cracking

Subgrade Preparation. Low to moderate plasticity clays are expected to be encountered or exposed at pavement subgrade. The pavement subgrade should be placed in loose lifts not exceeding 8 inches and should be uniformly compacted to a minimum of 95 percent maximum dry density (per ASTM D-698) and within ±2 percent of the optimum moisture content. We recommend the subgrade be stabilized using the following:

Location Reagent Application Rate

(pounds per square yard)

Application Depth (inches)

Rigid and Flexible Pavement Lime 27 6

Lime stabilization should be performed in accordance with TxDOT Standard

Proposed Liberty Hill City Park- Parking Lot, 255 County Road 200

Specifications, Item 260, “Lime Stabilized Subgrade”, or local equivalent.

Cautionary Note Regarding Stabilized Subgrades. Stabilized subgrades are not suitable for supporting heavy construction traffic. Stabilized subgrades that have been subjected to heavy construction traffic should be re-inspected and re-stabilized as necessary prior to the construction of overlying pavement.

Pavement subgrade recommendations provided here assume the subgrade soil receiving lime treatment has sulfate concentrations less than 3,000 ppm. The identification of sulfate sources often occurs in seams and stratified pockets and can occur in small, localized areas, thus additional onsite sulfate testing should be performed during construction and after the site is graded. As an alternate, flexible base can be used in lieu of lime stabilization and to the same depths recommended for lime stabilization.

Flexible base should consist of crushed aggregate base meeting TxDOT Standard Specifications, Item 247, Grade 1-2, Type A or D, or local equivalent. Flexible base should be compacted to at least 95 percent maximum dry density (per ASTM D-698) and within ±2 percent of the optimum moisture content.

6.3.2 Rigid Pavements

Portland cement concrete (PCC) with a minimum 28-day compressive strength of 3,500 pounds per square inch (psi) should be utilized for rigid pavement. Grade 60 reinforcing steel should be utilized in the transverse and longitudinal directions. The following pavement thicknesses and reinforcing are recommended:

Paving Use Thickness (inches) Reinforcing

Parking Areas for Automobiles and Light Trucks 5 No. 3 bars spaced on 22-inch intervals

Fire Lane, Bus Lane and Drive Lanes and Areas Subjected to Light to Medium

Trucks 6 No. 3 bars spaced on 18-inch intervals

Areas Receiving Heavy Trucks and Dumpsters 7 No. 3 bars spaced on 16-inch intervals

Note:

1. Recommended pavement reinforcement is in accordance with ACI guidelines.

Alternate Pavement Thickness. Concrete pavement thicknesses provided above can be increased an extra 1 inch (corresponding reinforcing requirements must be changed) as a substitution for stabilization of the pavement subgrade, provided a passing proof-roll is achieved prior to placement of reinforcing steel at the pavement subgrade areas

Pavement Joints. Contraction joints should be spaced at about 25 times the pavement thickness up to a maximum of 15 feet in any direction. Saw cut control joints should be cut within 6 to 12 hours of concrete placement. ACI recommendations indicate that regularly spaced expansion joints may be deleted from concrete pavements. Therefore, the installation of expansion joints is optional and should be evaluated by the Civil Engineer. Dowels should have a diameter equal to 1/8 the slab thickness, be spaced on

Proposed Liberty Hill City Park- Parking Lot, 255 County Road 200

12-inch intervals, and be embedded at least 9 inches. Appropriate joint sealant is recommended to keep water from saturating the pavement subgrade and to prevent the introduction of incompressible material into the joints. Routine monitoring and maintenance of joint sealants are recommended. Where not specified herein, concrete pavement should comply with Texas Department of Transportation (TxDOT) Standard Specifications, Item 360, "Concrete Pavement", or local equivalent.

6.3.3 Flexible Pavements

General. Flexible asphaltic pavements subjected to soil-related shrinking and swelling do not perform as well as rigid pavements. As a result, the lifespan of flexible asphaltic pavement can be reduced substantially when compared to rigid pavement. The need for increased maintenance of flexible asphaltic pavements should be considered prior to its selection.

The following Hot Mix Asphalt (HMA) paving sections are recommended:

Paving Use Asphalt Thickness (inches)

Aggregate Base Thickness (inches)

Parking Areas for Automobiles and Light Trucks 2 8

Fire Lane and Drive Lanes and Areas Subjected to Light to Medium Trucks 2.5 10

Asphaltic concrete pavement should comply with TxDOT Standard Specifications, Item 340, “Dense-Graded Hot-Mix Asphalt (Method)”, or local equivalent. The flexible base course should comply with TxDOT Standard Specifications, Item 247, Grade 1-2, Type A or D, “Flexible Base”, or equivalent.

7.0 LIMITATIONS/GENERAL COMMENTS

As with any geotechnical engineering report, this report presents technical information and provides detailed technical recommendations for civil and structural engineering design and construction purposes. UES, by necessity, has assumed the user of this document possesses the technical acumen to understand and properly utilize the information and recommendations provided herein. UES strives to be clear in its presentation and, like the user, does not want potentially detrimental misinterpretation or misunderstanding of this report. Therefore, we encourage any user of this report with questions regarding its content to contact UES for clarification. Clarification will be provided verbally and/or issued by UES in the form of a report addendum, as appropriate.

Professional services provided in this geotechnical exploration were performed, findings obtained, and recommendations prepared in accordance with generally accepted geotechnical engineering principles and practices. The scope of services provided herein does not include an environmental assessment of the site or investigation for the presence or absence of hazardous materials in the soil, surface water or groundwater.

Proposed Liberty Hill City Park- Parking Lot, 255 County Road 200

UES Project No. Y252041 June 25, 2025

UES, upon written request, can be retained to provide these services.

UES is not responsible for conclusions, opinions or recommendations made by others based on this data. Information contained in this report is intended for the exclusive use of the Client (and their designated design representatives), and is related solely to design of the specific structures outlined in Section 1.0. No party other than the Client (and their designated design representatives) shall use or rely upon this report in any manner whatsoever unless such party shall have obtained UES’s written acceptance of such intended use. Any such third party using this report after obtaining UES’s written acceptance shall be bound by the limitations and limitations of liability contained herein, including UES’s liability being limited to the fee paid to it for this report. Recommendations presented in this report should not be used for design of any other structures except those specifically described in this report. In all areas of this report in which UES may provide additional services if requested to do so in writing, it is presumed that such requests have not been made if not evidenced by a written document accepted by UES. Further, subsurface conditions can change with passage of time. Recommendations contained herein are not considered applicable for an extended period of time after the completion date of this report. It is recommended our office be contacted for a review of the contents of this report for construction commencing more than one (1) year after completion of this report. Non-compliance with any of these requirements by the Client or anyone else shall release UES from any liability resulting from the use of, or reliance upon, this report.

Recommendations provided in this report are based on our understanding of information provided by the Client about characteristics of the project. If the Client notes any deviation from the facts about project characteristics, UES should be contacted immediately since this may materially alter the recommendations. Further, UES is not responsible for damages resulting from workmanship of designers or contractors. It is recommended the Owner retain qualified personnel, such as a Geotechnical Engineering firm, to verify construction is performed in accordance with plans and specifications.

Appendix A - Boring Location Plan

BORING LOCATION PLAN

UES Project No. Y252041 Liberty Hill City Park Parking Lot

Appendix B - Boring Logs

P= 4.5

N= 67

N= 62

N= 74

N= 61

N= 56

CLAYEY GRAVEL, with fat clay seams, dark brown, very stiff.

(GC)

Same as above, hard.

Same as above.

CLAYEY GRAVEL, light brown, hard. (GC)

GRAVELLY LEAN CLAY, with calcareous material, light brown, hard. (CL)

Same as above.

Test boring was terminated at a depth of 10-feet.

SH

S-1

SS

S-2

SS

S-3

SS

S-4

SS

S-5

SS

S-6

S A

M P

LE

N

U M

B E

R

PI

P

LA

S

T

IC

IT

Y

IN

D

E X

M O

IS

T

U R

E C

O N

T E

N T

LL

LI

Q

U

ID

L

IM

IT

FIELD DATA

CLIENT:

PROJECT:

LOCATION:

NUMBER:

SHEET 1 of 1

DRILLING METHOD(S):

GROUNDWATER INFORMATION:

DATE(S) DRILLED: 5/2/2025

SURFACE ELEVATION:

REMARKS:

N : B

LO

W

S /F

T P

: T O

N S

/S Q

F T

T : T

O N

S /S

Q F

T Q c:

T

O N

S /S

Q F

T

ATTERBERG

LIMITS

Solid Flight

Groundwater was not encountered during drilling.

The borehole was drya nd open upon completion of drilling.

Test boring depths were determined by UES, test boring locations were determined by Kimley-Horn and Associates.Drilling operations were performed by Texas Geo Bore a subcontractor to UES.

UES PROFESSIONAL SOLUTIONS 44, LLC

7 Roundville Lane Round Rock, Texas 78664 Telephone: 512-284-8022 Fax: 512-284-7764

Kimley-Horn and Associates, Inc

Liberty Hill City Park- Parking Lot

255 County Road 200; Liberty Hill, TX

Y252041 S

A M

P

LE

S

LABORATORY DATA

C O

M P

R E

S S

IV

E

S T

R E

N G

T H

(T O

N S

/S Q

F T

M

IN

U S

N O

. 2

S

IE

V E

D R

Y D

E N

S

IT

Y

P O

U N

D S

/C U

.F T

D E

P T

H

F T

S O

IL

S

Y M

B O

L

P

LA

S T

IC

L

IM

IT

PL

LOG OF BORING B-1

DESCRIPTION OF STRATUM

N - STANDARD PENETRATION TEST RESISTANCE

Qc - STATIC CONE PENETROMETER TEST INDEX

P - POCKET PENETROMETER RESISTANCE

LO

G

_O F

_B O

R

IN

G L

O G

S O

F B

O R

IN

G

.G P

J R

O C

K _E

T L.

G D

T

6/

N= 44

N= 51

N= 70

N= 67

N= 74

CLAYEY SAND, brown, very stiff. (SC)

Same as above, with calcareous material, hard.

CLAYEY GRAVEL, light brown, hard. (GC)

Same as above.

Same as above.

Test boring was terminated at a depth of 10-feet.

SS

S-1

SS

S-2

SS

S-3

SS

S-4

SS

S-5

S A

M P

LE

N

U M

B E

R

PI

P

LA

S

T

IC

IT

Y

IN

D

E X

M O

IS

T

U R

E C

O N

T E

N T

LL

LI

Q

U

ID

L

IM

IT

FIELD DATA

CLIENT:

PROJECT:

LOCATION:

NUMBER:

SHEET 1 of 1

DRILLING METHOD(S):

GROUNDWATER INFORMATION:

DATE(S) DRILLED: 5/2/2025

SURFACE ELEVATION:

REMARKS:

N : B

LO

W

S /F

T P

: T O

N S

/S Q

F T

T : T

O N

S /S

Q F

T Q c:

T

O N

S /S

Q F

T

ATTERBERG

LIMITS

Solid Flight

Groundwater was not encountered during drilling.

The borehole was drya nd open upon completion of drilling.

Test boring depths were determined by UES, test boring locations were determined by Kimley-Horn and Associates.Drilling operations were performed by Texas Geo Bore a subcontractor to UES.

UES PROFESSIONAL SOLUTIONS 44, LLC

7 Roundville Lane Round Rock, Texas 78664 Telephone: 512-284-8022 Fax: 512-284-7764

Kimley-Horn and Associates, Inc

Liberty Hill City Park- Parking Lot

255 County Road 200; Liberty Hill, TX

Y252041 S

A M

P

LE

S

LABORATORY DATA

C O

M P

R E

S S

IV

E

S T

R E

N G

T H

(T O

N S

/S Q

F T

M

IN

U S

N O

. 2

S

IE

V E

D R

Y D

E N

S

IT

Y

P O

U N

D S

/C U

.F T

D E

P T

H

F T

S O

IL

S

Y M

B O

L

P

LA

S T

IC

L

IM

IT

PL

LOG OF BORING B-2

DESCRIPTION OF STRATUM

N - STANDARD PENETRATION TEST RESISTANCE

Qc - STATIC CONE PENETROMETER TEST INDEX

P - POCKET PENETROMETER RESISTANCE

LO

G

_O F

_B O

R

IN

G L

O G

S O

F B

O R

IN

G

.G P

J R

O C

K _E

T L.

G

N= 30

N= 56

N= 42, 50/3"

N= 30

SANDY LEAN CLAY, with calcareous material, brown, very stiff. (CL)

Same as above, hard

Same as above.

SANDY LEAN CLAY, with calcareous material, light brown, very stiff. (CL)

Test boring was terminated at a depth of 10-feet.

5117 5

SS

S-1

SS

S-2

SS

S-3

SS

S-4

S A

M P

LE

N

U M

B E

R

PI

P

LA

S

T

IC

IT

Y

IN

D

E X

M O

IS

T

U R

E C

O N

T E

N T

LL

LI

Q

U

ID

L

IM

IT

FIELD DATA

CLIENT:

PROJECT:

LOCATION:

NUMBER:

SHEET 1 of 1

DRILLING METHOD(S):

GROUNDWATER INFORMATION:

DATE(S) DRILLED: 5/2/2025

SURFACE ELEVATION:

REMARKS:

N : B

LO

W

S /F

T P

: T O

N S

/S Q

F T

T : T

O N

S /S

Q F

T Q c:

T

O N

S /S

Q F

T

ATTERBERG

LIMITS

Solid Flight

Groundwater was not encountered during drilling.

The borehole was drya nd open upon completion of drilling.

Test boring depths were determined by UES, test boring locations were determined by Kimley-Horn and Associates.Drilling operations were performed by Texas Geo Bore a subcontractor to UES.

UES PROFESSIONAL SOLUTIONS 44, LLC

7 Roundville Lane Round Rock, Texas 78664 Telephone: 512-284-8022 Fax: 512-284-7764

Kimley-Horn and Associates, Inc

Liberty Hill City Park- Parking Lot

255 County Road 200; Liberty Hill, TX

Y252041 S

A M

P

LE

S

LABORATORY DATA

C O

M P

R E

S S

IV

E

S T

R E

N G

T H

(T O

N S

/S Q

F T

M

IN

U S

N O

. 2

S

IE

V E

D R

Y D

E N

S

IT

Y

P O

U N

D S

/C U

.F T

D E

P T

H

F T

S O

IL

S

Y M

B O

L

P

LA

S T

IC

L

IM

IT

PL

LOG OF BORING B-3

DESCRIPTION OF STRATUM

N - STANDARD PENETRATION TEST RESISTANCE

Qc - STATIC CONE PENETROMETER TEST INDEX

P - POCKET PENETROMETER RESISTANCE

LO

G

_O F

_B O

R

IN

G L

O G

S O

F B

O R

IN

G

.G P

J R

O C

K _E

T L.

G

N= 57

N= 59

N= 62

N= 48

CLAYEY SAND, light brown, hard. (SC)

Same as above.

Same as above.

CLAYEY SAND, light brown, very stiff. (SC)

Test boring was terminated at a depth of 10-feet.

15 23SS

S-1

SS

S-2

SS

S-3

SS

S-4

S A

M P

LE

N

U M

B E

R

PI

P

LA

S

T

IC

IT

Y

IN

D

E X

M O

IS

T

U R

E C

O N

T E

N T

LL

LI

Q

U

ID

L

IM

IT

FIELD DATA

CLIENT:

PROJECT:

LOCATION:

NUMBER:

SHEET 1 of 1

DRILLING METHOD(S):

GROUNDWATER INFORMATION:

DATE(S) DRILLED: 5/2/2025

SURFACE ELEVATION:

REMARKS:

N : B

LO

W

S /F

T P

: T O

N S

/S Q

F T

T : T

O N

S /S

Q F

T Q c:

T

O N

S /S

Q F

T

ATTERBERG

LIMITS

Solid Flight

Groundwater was not encountered during drilling.

The borehole was drya nd open upon completion of drilling.

Test boring depths were determined by UES, test boring locations were determined by Kimley-Horn and Associates.Drilling operations were performed by Texas Geo Bore a subcontractor to UES.

UES PROFESSIONAL SOLUTIONS 44, LLC

7 Roundville Lane Round Rock, Texas 78664 Telephone: 512-284-8022 Fax: 512-284-7764

Kimley-Horn and Associates, Inc

Liberty Hill City Park- Parking Lot

255 County Road 200; Liberty Hill, TX

Y252041 S

A M

P

LE

S

LABORATORY DATA

C O

M P

R E

S S

IV

E

S T

R E

N G

T H

(T O

N S

/S Q

F T

M

IN

U S

N O

. 2

S

IE

V E

D R

Y D

E N

S

IT

Y

P O

U N

D S

/C U

.F T

D E

P T

H

F T

S O

IL

S

Y M

B O

L

P

LA

S T

IC

L

IM

IT

PL

LOG OF BORING B-4

DESCRIPTION OF STRATUM

N - STANDARD PENETRATION TEST RESISTANCE

Qc - STATIC CONE PENETROMETER TEST INDEX

P - POCKET PENETROMETER RESISTANCE

LO

G

_O F

_B O

R

IN

G L

O G

S O

F B

O R

IN

G

.G P

J R

O C

K _E

T L.