10-9. KIMLEY HORN PRELIM GEOTECHNICAL REPORT IRISH ACRES TO SS WM INTERCONNECT 326 JACKSONVILLE RD.pdf

November 4, 2024

GPGT-23-172

To: Kimley - Horn and Associates, Inc.

1700 SE 17th Street, Suite 200 Ocala, Florida 34771

Attention: Mr. Alan Garri, P.E.

Subject: Preliminary Geotechnical Investigation, Irish Acres to Silver Springs

Regional Water Main Interconnect, FL-326 and NE Jacksonville Road, Marion County, Florida

Dear Mr. Garri:

As requested, Andreyev Engineering, Inc. (AEI) has completed a preliminary geotechnical investigation for the above-referenced project location. We understand that you are planning to install new sections of water main pipeline to connect the Marion County Utilities (MCU) Irish Acres facility to the Silver Springs Regional potable water system. This report focuses on the section located near the intersection of FL-326 and NE Jacksonville Road.

This report presents the results of our preliminary geotechnical investigation along with an evaluation of the soil and groundwater conditions encountered. In addition, it provides geotechnical engineering recommendations for the design and construction of the proposed pipeline.

SITE LOCATION AND DESCRIPTION

The proposed new pipeline is located near the intersection of FL-326 and NE Jacksonville Road, in Ocala, Marion County, Florida. The subject site is located within Section 21, Township 14 South, and Range 22 East. We have included the U.S.G.S. Topographic Map, which depicts the location of the site, on the attached Figure 1. In addition, the Natural Resources Conservation Service (NRCS) Soil Map, which depicts the location and general soil types of the subject site, is presented on the attached Figure 2.

PURPOSE AND SCOPE OF SERVICES

The purpose of this study was to explore subsurface soil and groundwater conditions at the subject site to provide recommendations for the design and construction of the proposed new water main.

The scope of this investigation included:

Drilled two (2) auger borings, designated as HA-13 and HA-14, to a depth of 10 feet below ground surface, along the proposed pathway of the new pipeline, for soil and groundwater evaluation.

Preliminary Geotechnical Investigation, Irish Acres to Silver Springs Regional Water Main Interconnect FL-326 & NE Jacksonville Road, Marion County, Florida

Samples were recovered from the borings and returned to AEI’s laboratory for visual classification and stratification. Soil strata were classified according to the Unified Soil Classification System (USCS). Approximate boring locations are shown on Figure 3, results of the auger borings, in profile form, are presented on Figure 4. On the profiles, horizontal lines designating the interface between differing materials represent approximate boundaries. The actual transition between layers is typically gradual.

NATURAL RESOURCES CONSERVATION SERVICE SOIL SURVEY

The publication titled “Soil Survey of Marion County, Florida” published by the U.S. Department of Agriculture, Natural Resources Conservation Service (NRCS) was reviewed. For your reference, we have included a portion of the NRCS Soil Map which depicts the location of the subject site on the attached Figure 2. The one soil map unit identified to exist at the subject site is presented as follows:

Soil Map Unit 9: Arredondo Sand - 0 to 5 Percent Slopes

Brief Description: "This is a nearly level to gently sloping, well drained soil that occurs as both small and large areas in the upland. It has a soil profile described as representative for the series.

In a representative profile the surface layer is dark grayish brown sand about 7 inches thick. The subsurface layer is mixed yellowish brown and dark yellowish brown sand about 11 inches thick.

The subsoil extends to a depth of 90 inches or more. In sequence downward, it is 28 inches of yellowish brown sand mottled with strong brown, 19 inches of strong brown sand having a few white mottles, 5 inches of strong brown loamy sand, and 20 inches of strong brown fine sandy loam. The water table is at a depth of more than 72 inches. Available water capacity is low in the upper 65 inches, medium from 65 to 70 inches, and medium to high below. Permeability is rapid in the upper 65 inches, moderately rapid from 65 to 70 inches, and moderate below. Organic matter content is low. These soils have slight limitations for use as septic tank absorption fields, dwellings with and without basements, small commercial buildings, and local roads and streets.”

SOIL AND GROUNDWATER CONDITIONS

The soil types encountered at the boring locations are presented in the form of soil profiles on the attached Figure 4. The stratification presented is based on visual examination of the recovered soil samples and the interpretation of the field logs by a geotechnical engineer.

Soil Conditions

In general, the borings encountered the following soil Strata:

Grayish Brown to Light Brown to Brown Fine Sand (SP) Stratum 1

Grayish Brown Slightly Silty Fine Sand (SP-SM) Stratum 2

Minor variations of the above Strata, including the presence of rock debris, have been noted on the soil logs, and are represented by sub-Stratum A on the attached Figure 4.

Please refer to Figures 3 and 4 for boring locations, strata depths, and encountered soil conditions. The stratification lines represent the approximate boundaries between soil types. The

Preliminary Geotechnical Investigation, Irish Acres to Silver Springs Regional Water Main Interconnect actual transition may be gradual. Minor variations not considered important to our engineering evaluations may have been abbreviated or omitted for clarity.

Groundwater Conditions

Groundwater was not encountered within the termination depths of 10 feet below existing ground surface at the boring locations. Based on the encountered subsurface conditions, our local experience, review of the NRCS Soil Survey, and antecedent rainfall conditions, it is our opinion that the normal seasonal high groundwater levels at the borings locations exists at or below the termination depths of 10 feet below existing ground surface.

EVALUATIONS AND RECOMMENDATIONS

Proposed New Pipeline

Based on the results of this investigation and our evaluation of the encountered subsurface conditions, it is our opinion that the site soils are generally suitable for construction of the proposed new pipeline sections, provided that proper site soil preparation and soil densification are carried out. It is critical that site preparation and soil densification procedures are thorough to ensure consistent and uniform support conditions for the proposed site improvements.

The soils encountered at HA-13 and HA-14 are all sandy soils, with some silt in the soils just below the surface. Boring HA-14 encountered varying amounts of rock debris from the surface to the termination depth of 10 feet, with more rock being present near the surface. Sandy soils are ideal for construction of the proposed pipeline, and groundwater is not expected to be an issue. As we did not encounter groundwater to a depth of 10 feet at either of these boring locations, we cannot accurately speak to the existing and/or normal seasonal high groundwater levels that exist at or below the termination depths at these locations.

On-site Stratum 1 fine sands, excavated from the site during construction, are considered suitable for use as general fill, provided minimal root/organic debris content and that the soil’s moisture content is maintained near optimum prior to fill placement and compaction. The Stratum 2 slightly silty sands are considered marginally suitable for use as general fill, and we recommend screening/filtering of these soils if they are to be used for filling materials. We also recommend removal of rock debris from soils that are to be used for filling materials.

Bedding and Backfill Recommendations

The bottom of the excavations and backfill in areas of granular soils should be compacted using small hand-operated equipment. Bedding and backfill up to 6 inches above the top of the pipe should consist of fine sand having less than 12% passing the U.S. #200 standard sieve. The pipes may be laid on a gravel bed or directly on the trench bottom provided that the natural soil at the foundation level is granular. The trench bottom should be compacted to 95 percent of its Modified Proctor Density to a minimum depth of one foot. Pumping or disturbed soils shall be over-excavated and replaced with dry granular materials. Backfilling shall progress as rapidly as the construction and testing of the work will permit. The initial backfill shall be carefully deposited on both sides of the pipe at the same time and uniformly compacted around the barrel of the pipe until enough has been placed to provide a cover of one foot above the crown of the pipe. In no case shall backfill material be placed in the trench in a manner that will cause shock to, or unequal pressure on, the pipe. The backfill shall be placed and compacted to 95 percent of maximum density as determined by AASHTO T-180 or as directed by the Geotechnical Engineer. Under no conditions should construction debris, concrete, etc., be included with the backfill. While

Preliminary Geotechnical Investigation, Irish Acres to Silver Springs Regional Water Main Interconnect groundwater was not encountered at either boring location, it is possible that groundwater levels may rise, that groundwater may be present in other areas not covered by the borings, and that rain events can saturate these soils. In such cases, sufficient time and adequate drying procedures should be provided to produce soil with a moisture content which is +/- 2 percent of optimum. It may be more practical in some cases to bring in dry material from offsite than to dry the excavated soils, however based on the boring results, we believe that there is sufficient backfill material present on-site.

Excavations

Any and all excavations should be constructed in accordance with applicable local, state and federal regulation including those outlined by the Occupational Safety and Health Administration (OSHA). It is the contractor’s sole responsibility for designing and constructing safe and stable excavations. Excavations should be sloped, benched or braced as required to maintain stability of the excavation sides and bottoms. Excavations should take into account loads resulting from equipment, fill stockpiles and existing construction. Any shoring needed to maintain a safe excavation should be designed by a professional engineer registered in the State of Florida in accordance with local, state and federal guidelines.

LIMITATIONS

This report has been prepared for the exclusive use of Kimley - Horn and Associates, Inc., and their designers, based on our understanding of the project as stated in this report. Any modifications in design concepts from the description stated in this report should be made known to AEI for possible modification of recommendations presented in this report. This exploration was performed in accordance with generally accepted soil and foundation engineering practices. No other warranty, expressed or implied, is made as to the professional advice presented herein.

Statements regarding all geotechnical recommendations are for use by the designers and are not intended for use by potential contractors. The geotechnical exploration and recommendations submitted herein are based on the data obtained from the soil borings presented on Figure 4.

The report does not reflect any variations which may occur adjacent to, between, or away from the borings. The nature and extent of the variations between the borings may not become evident until during construction. If variations then appear evident, it will be necessary to re-evaluate the recommendations presented in this report. An on-site visit may be required by a geotechnical engineer to note the characteristics of the variations during the construction period. This geotechnical study investigated the soil conditions within the proposed new pipeline areas, to drilled depths of 10 feet below ground surface and was not intended to investigate deeper soil conditions with regards to the presence or absence of Karst activity.

CLOSURE

AEI appreciates the opportunity to participate in this project, and we trust that the information herein is sufficient for your immediate needs. If you have any questions or comments concerning the contents of this report, please do not hesitate to contact the undersigned.

Sincerely, Preliminary Geotechnical Investigation, Irish Acres to Silver Springs Regional Water Main Interconnect

ANDREYEV ENGINEERING, INC.

Frank Moschette, E.I. Raymond W. Jones, P.E.

Project Engineer Vice President Florida Registration No.58079

Figures & Attachments:

Figure 1: U.S.G.S. Topographic Map Figure 2: N.R.C.S. Soil Survey Figure 3: Boring Location Plan Figure 4: Soil Profiles

FIGURES

HA-13

HA-14

Andreyev Engineering, Inc.

GRAPHIC SCALE: 1"=2000'

2000 40001000

IRISH ACRES TO SILVER

SPRINGS INTERCONNECT

Andreyev Engineering, Inc.

GRAPHIC SCALE: 1"=300'

300 600150

Andreyev Engineering, Inc.0

GRAPHIC SCALE: 1"=100'

100 20050

Andreyev Engineering, Inc.