Tomoka_Farms_Landfill_PEMB_Structure_Geotech_Report.pdf

Subsurface Soil Exploration and Geotechnical Engineering Evaluation

Proposed PEMB Structure Tomoka Farms Landfill Volusia County, Florida

Ardaman & Associates, Inc.

CORPORATE HEADQUARTERS

8008 S. Orange Avenue, Orlando, Florida 32809 - Phone: (407) 855-3860 Fax: (407) 859-8121

Branch Office Locations

Florida: Bartow, Cocoa, Fort Myers, Miami, Orlando, Port St. Lucie, Sarasota, Tallahassee, Tampa, West Palm Beach Louisiana: Baton Rouge, New Orleans, Shreveport

Texas: Houston

MEMBERS:

ASTM International

Society of American Military Engineers American Council of Engineering Companies

8008 S. Orange Avenue (32809), Post Office Box 593003, Orlando, Florida 32859-3003 Phone: (407) 855-3860 Fax: (407) 859-8121

Florida: Bartow, Cocoa, Fort Myers, Miami, Orlando, Port St. Lucie, Sarasota, Tallahassee, Tampa, West Palm Beach Louisiana: Baton Rouge, New Orleans, Shreveport

Texas: Houston

January 20, 2025 Ardaman File No. 24-6430

Bentley Group, Inc.

651 Warren Avenue, Suite 200 Longwood, Florida 32750

Attention: Mr. Brenton Daily, P.E.

Subject: Subsurface Soil Exploration and Geotechnical Engineering Evaluation Proposed PEMB Structure Tomoka Farms Landfill Volusia County, Florida

Dear Mr. Daily:

As requested and authorized, we have completed a shallow subsurface soil exploration for the subject project. The purposes of performing this exploration were to evaluate the general subsurface conditions within the building area and to provide recommendations for site preparation and foundation support. In addition, we have estimated the normal seasonal high groundwater level at the boring locations. This report documents our findings and presents our engineering recommendations.

SITE LOCATION AND SITE DESCRIPTION

The site for the proposed pre-engineered metal building (PEMB) is located on Tomoka Landfill Road to the west of Tomoka Farms Road in Volusia County, Florida (Section 9, Township 16 South, Range 32 East). The general site location is shown superimposed on the Daytona Beach, Florida U.S.G.S. quadrangle map presented on Figure 1.

The site of the proposed structure is currently a concrete paved parking area.

PROPOSED CONSTRUCTION AND GRADING

It is our understanding that the proposed development includes a one-story pre-engineered metal structure. The proposed building will consist of load bearing walls and interior columns with slab-on-grade floors. For the purposes of our analysis, we have assumed the maximum loading conditions for the structure to be on the order of 2 to 4 kips per linear foot for wall foundations, 50 kips for individual column foundations, and 100 pounds per square foot (psf) for slab-on-grade floors. Grading plans are not complete at this time, therefore we have assumed that 0 to 1 foot of fill is required to raise the building area to final elevation. If actual building loads exceed our assumptions, then the recommendations in this report may not be valid.

Geotechnical, Environmental and Materials Consultants

Bentley Group, Inc. January 20, 2025 Ardaman File No. 24-6430 -2-

REVIEW OF SOIL SURVEY MAPS

Based on information obtained online from the Web Soil Survey as operated by the U.S.

Department of Agriculture Natural Resources Conservation Services, the site is located in an area mapped as the “Pomona fine sand” soil series, which consists of sandy soil in low, broad areas within the flatwoods. The internal drainage of the "Pomona fine sand" is poor and the soil permeability is moderate to rapid. According to the Soil Survey, the seasonal high water table for the "Pomona fine sand" soil series is typically within 10 inches for 1 to 3 months.

FIELD EXPLORATION PROGRAM

SPT Borings

The field exploration program included performing two Standard Penetration Test (SPT) borings.

The SPT borings were advanced to a depth of 25 feet below the existing ground surface generally using the methodology outlined in ASTM D-1586. A summary of this field procedure is included in the Appendix.

Soil samples recovered during performance of the borings were visually classified in the field and representative portions of the samples were transported to our laboratory in sealed sample jars.

The groundwater level at each of the boring locations was measured during drilling. The borings were backfilled with soil cuttings.

Test Locations

The approximate locations of the borings are schematically illustrated on an aerial photograph of the subject site shown on Figure 2. These locations were determined in the field by tape measuring/estimating distances from existing site features and should be considered accurate only to the degree implied by the method of measurement used.

LABORATORY PROGRAM

Representative soil samples obtained during our field sampling operation were packaged and transferred to our laboratory for further visual examination and classification. The soil samples were classified using visual-manual procedures in general accordance with the Unified Soil Classification System (ASTM D-2488). The resulting soil descriptions are shown on the soil boring profiles presented on Figure 3.

In addition, we conducted three percent fines analyses (ASTM D-1140) on selected soil samples obtained from the borings. The results of these tests are presented adjacent to the sample depth on the boring profiles on Figure 3.

Ardaman File No. 24-6430 -3-

GENERAL SUBSURFACE CONDITIONS

General Soil Profile

The results of the field exploration and laboratory programs are graphically summarized on the soil boring profiles presented on Figure 3. The stratification of the boring profiles represents our interpretation of the field boring logs and the results of laboratory examinations of the recovered samples. The stratification lines represent the approximate boundary between soil types. The actual transitions may be more gradual than implied.

The results of the borings indicate the following general soil profile:

Depth Below Ground Surface (feet) Description

From To 0 1½ Loose fine sand (SP)

1½ 9 Medium dense to very dense fine sand (SP), fine sand with silt (SP-SM), and fine sand with clay (SP-SC)

9 12½ Medium dense fine sand with clay (SP-SC) to clayey fine sand (SC)

12½ 22½ Very loose fine sand with clay (SP-SC) to clayey fine sand (SC)

22½ 25 Loose to medium dense fine sand (SP) and clayey fine sand (SC)

The above soil profile is outlined in general terms only. Please refer to Figure 3 for soil profile details.

We note that the thickness of concrete shown on the boring profile for Boring TH-2 should be considered a rough approximation only. Coring of the pavement section would be required to provide accurate thickness measurements.

Groundwater Level

The groundwater level was measured in the boreholes during drilling. As shown on Figure 3, groundwater was encountered at a depth of approximately 6 feet below the existing ground surface on the date indicated. Fluctuation in groundwater levels should be anticipated throughout the year primarily due to seasonal variations in rainfall and other factors that may vary from the time the borings were conducted.

Ardaman File No. 24-6430 -4-

NORMAL SEASONAL HIGH GROUNDWATER LEVEL

The groundwater level is affected by a number of factors. The amount of rainfall and the drainage characteristics of the soils, the land surface elevation, relief points such as drainage ditches, lakes, rivers, swamp areas, etc., and distance to relief points are some of the more important factors influencing the groundwater level.

The normal seasonal high groundwater level each year is the level in the August-September period at the end of the rainy season during a year of normal (average) rainfall. The water table elevations associated with a higher than normal rainfall and in the extreme case, flood, would be higher to much higher than the normal seasonal high groundwater level, and could occur at times outside of the August-September period. The normal high water levels would more approximate the normal seasonal high groundwater levels.

Based on our interpretation of the site conditions using our boring logs, we estimate the normal seasonal high groundwater level at the boring locations to be approximately 2 feet above the groundwater levels measured at the time of our field exploration.

ENGINEERING EVALUATION AND RECOMMENDATIONS

General

The results of our exploration indicate that, with proper site preparation as recommended in this report, the existing soils are suitable for supporting the proposed building on a conventional shallow foundation system. Spread footings should provide an adequate support system for the structure.

The following are our recommendations for overall site preparation and foundation support for the proposed structure based on the existing soil conditions encountered during the exploration. The recommendations are made as a guide for the design engineer, parts of which should be incorporated into the project's specifications.

Stripping and Grubbing/Root-Raking

The "footprint" of the proposed building, and other hardscape areas, plus a minimum margin of five feet, should be stripped of all surface vegetation, stumps, debris, organic topsoil or other deleterious materials, as encountered.

After stripping, the site should be grubbed/root-raked such that roots with a diameter greater than ½ inch, stumps, or small roots in a dense state, are completely removed. Based on the boring log information, significant root concentrations are estimated to be within the upper 1 to 2 feet.

The actual depth(s) of stripping and grubbing/root-raking must be determined by visual

Ardaman File No. 24-6430 -5-observation and judgment during the earthwork operation. Grubbing/root-raking should continue until determined to be adequate by Ardaman’s representative who is monitoring the root-raking.

All existing foundations, slabs, asphalt, and any other underground structures should be removed from the proposed construction area. If pipes or any collapsible or leak prone utilities are not removed or completely filled (with grout or concrete), they might serve as conduits for subsurface erosion resulting in excessive settlements. Over-excavated areas resulting from the removal of underground structures and unsuitable materials should be backfilled in accordance with the fill soils section of this report. This excavation must not undermine the existing building foundations.

Provide shoring, bracing, and/or underpinning of existing footings as necessary to protect from failure.

It has been our experience that soils surrounding existing buildings sometimes contain pockets of construction debris or other deleterious materials requiring removal and replacement with compacted clean fine sands. Therefore, we recommend that the stripped surface be inspected by Ardaman & Associates, Inc.

Proof-rolling

We recommend proof-rolling the cleared surface to locate any unforeseen soft areas or unsuitable surface or near-surface soils, to increase the density of the upper soils, and to prepare the existing surface for the addition of the fill soils (as required). Proof-rolling of the building area should consist of at least 10 passes of a compactor capable of achieving the density requirements described in the next paragraph. Each pass should overlap the preceding pass by 30 percent to achieve complete coverage. If deemed necessary, in areas that continue to "yield", remove all deleterious material and replace with clean, compacted sand backfill. The proof-rolling should occur after cutting and before filling. Proof-rolling should be monitored in the field by an Ardaman representative.

A density equivalent to or greater than 95 percent of the modified Proctor (ASTM D-1557) maximum dry density value for a depth of 2 feet in the building area must be achieved beneath the stripped and grubbed ground surface. Additional passes and/or overexcavation and recompaction may be required if these minimum density requirements are not achieved. The soil moisture should be adjusted as necessary during compaction.

Care should be exercised to avoid damaging any neighboring structures while the compaction operation is underway. Prior to commencing compaction, occupants of adjacent structures should be notified and the existing condition (i.e., cracks) of the structures documented with photographs and survey (if deemed necessary). Compaction should cease if deemed detrimental to adjacent structures, and Ardaman & Associates should be notified immediately. Heavy vibratory compaction should not be used within 200 feet of existing structures.

Ardaman File No. 24-6430 -6-

Suitable Fill Material and Compaction of Fill Soils

All fill materials should be free of organic materials, such as roots and vegetation. We recommend using fill with less than 12 percent by dry weight of material passing the U.S. Standard No. 200 sieve size. The fine sand and fine sand with silt (Strata No. 1 and 2 without roots, as shown on Figure 3) are suitable for use as fill materials and, with proper moisture control, should densify using conventional compaction methods. Soils with more than 12 percent passing the No. 200 sieve can be used in some applications, but will be more difficult to compact due to their inherent nature to retain soil moisture.

All structural fill should be placed in level lifts not to exceed 12 inches in uncompacted thickness.

Each lift should be compacted to at least 95 percent of the modified Proctor (ASTM D-1557) maximum dry density value. The filling and compaction operations should continue in lifts until the desired elevation(s) is achieved. If hand-held compaction equipment is used, the lift thickness should be reduced to no more than 6 inches.

Foundation Support by Spread Footings and Foundation Compaction Criteria

Foundations should be excavated to the proposed bottom of footing elevations and, thereafter, the in-place compaction for a depth of 2 feet below the footing bottoms should be verified. If necessary, compact the soils at the bottom of the excavations to at least 95 percent of the modified Proctor maximum dry density (ASTM D-1557) for a depth of 2 feet below the footing bottoms. Based on the existing soil conditions and, assuming the above outlined proof-rolling and compaction criteria are implemented, an allowable soil bearing pressure of 2,000 pounds per square foot (psf) may be used in the foundation design. This bearing pressure should result in foundation settlement within tolerable limits (i.e., 1 inch or less).

Bearing wall foundations should be a minimum of 18 inches wide and column foundations should be a minimum of 24 inches wide. A minimum soil cover of 18 inches should be maintained from the bottom of the foundations to the adjacent finished grades.

Where the proposed foundations are to be located adjacent to, or within 1 footing width of the existing foundations, the proposed foundations should be positioned so that the bottom elevations of the proposed foundations are equal to the bottom elevations of the existing foundations. It is noted that the foundation elements of the existing building must be adequately supported during excavation and placement of the proposed foundations. Methods of supporting the existing foundations should be determined by the Contractor or his engineer, but may include bracing, underpinning and/or other methods. Some settlement of the existing structure’s foundations can be expected to take place during construction. This settlement may result in cracking of the existing structure. The majority of the cracking, if it occurs, is expected to take place during and soon after construction. The construction budget should allow for any necessary repairs of the existing building.

Ardaman File No. 24-6430 -7-

Floor Slab Moisture Reducer and Slab Compaction Requirements

Prior to concrete placement, soil compaction beneath floor slabs should be verified for a depth of 12 inches and meet the 95 percent criteria (modified Proctor, ASTM D-1557).

Precautions should be taken during the slab construction to reduce moisture entry from the underlying subgrade soils. Moisture entry can be reduced by installing a membrane between the subgrade soils and floor slab. Care should be exercised when placing the reinforcing steel (or mesh) and slab concrete such that the membrane is not punctured. We note that the membrane alone does not prevent moisture from occurring beneath or on top of the slab.

If interior columns are isolated from the floor slab, an expansion joint should be provided around the columns and sealed with a water-proof sealant.

Dewatering

Based on the groundwater conditions encountered, the control of the groundwater may be required to achieve the necessary stripping and subsequent construction, backfilling, and compaction requirements presented in the preceding sections. The requirement for control of groundwater should particularly be anticipated for footing and utility excavations.

The actual method(s) of dewatering should be determined by the contractor. However, regardless of the method(s) used, we suggest drawing down the water table sufficiently, say 2 to 3 feet, below the bottom of any excavation or compaction surface to preclude "pumping" and/or compaction-related problems with the foundation soils. The dewatering should be performed in advance of any excavation to minimize soil disturbance caused by water seeping into the excavation.

QUALITY ASSURANCE

We recommend establishing a comprehensive quality assurance program to verify that all site preparation and foundation construction is conducted in accordance with the appropriate plans and specifications. Materials testing and inspection services should be provided by Ardaman & Associates.

As a minimum, an on-site engineering technician should monitor all stripping and grubbing to verify that deleterious materials have been removed and should observe the proof-rolling operation to verify that the appropriate number of passes are applied to the subgrade. In-situ density tests should be conducted during earthwork activities and below all structural areas including footings, floor slabs, and other hardscape areas to verify that the required densities have been achieved. In-situ density values should be compared to laboratory Proctor moisture-density results for each of the different natural and fill soils encountered.

Ardaman File No. 24-6430 -8-

Finally, we recommend inspecting and testing the construction materials for the foundations and other structural components.

IN-PLACE DENSITY TESTING FREQUENCY

In Central Florida, earthwork testing is typically performed on an on-call basis when the contractor has completed a portion of the work. The test result from a specific location is only representative of a larger area if the contractor has used consistent means and methods and the soils are practically uniform throughout. The frequency of testing can be increased and full-time construction inspection can be provided to account for variations. We recommend that the following minimum testing frequencies be utilized.

In proposed building areas, a minimum frequency of one in-place density test for each 2,500 square feet of area should be used, however a minimum 4 tests should be performed for building footprint areas less than 10,000 square feet. In-place density testing should be performed at this minimum frequency for a depth of 2 feet below natural ground and for every 1-foot lift of fill placed in the structural area. In addition, density tests should be performed in each column footing for a depth of 2 feet below the bearing surface. For continuous or wall footings, density tests should be performed at a minimum frequency of one test for every 50 linear feet of footing, and for a depth of 2 feet below the bearing surface.

Representative samples of the various natural ground and fill soils, as well as stabilized subgrade (where applicable) and base materials should be obtained and transported to our laboratory for Proctor compaction tests. These tests will determine the maximum dry density and optimum moisture content for the materials tested and will be used in conjunction with the results of the in-place density tests to determine the degree of compaction achieved.

CLOSURE

The analyses and recommendations submitted herein are based on the data obtained from the soil borings presented on Figure 3 and the assumed loading conditions. This report does not reflect any variations which may occur adjacent to or between 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 after performing on-site observations during the construction period and noting the characteristics of the variations.

In the event any changes occur in the design, nature, or location of the proposed facility, we should review the applicability of conclusions and recommendations in this report. We recommend a general review of final design and specifications by our office to verify that earthwork and foundation recommendations are properly interpreted and implemented in the design specifications. Ardaman & Associates should attend the pre-bid and preconstruction

Ardaman File No. 24-6430 -9-meetings to verify that the bidders/contractor understand the recommendations contained in this report.

Because of Ardaman & Associates’ familiarity with this site and the proposed development gained through performing the subsurface soil exploration and geotechnical engineering evaluation as presented in this report, Ardaman & Associates is best suited to provide monitoring and testing services during earthwork, and to provide continued evaluation and guidance during construction should variations in the soil conditions be encountered.

This study is based on a relatively shallow exploration and is not intended to be an evaluation for sinkhole potential. This study does not include an evaluation of the environmental (ecological or hazardous/toxic material related) condition of the site and subsurface.

This report has been prepared for the exclusive use of Bentley Group, Inc. in accordance with generally accepted geotechnical engineering practices for the purpose of the proposed PEMB structure. No other warranty, expressed or implied, is made.

Ardaman File No. 24-6430 -10-

We are pleased to be of assistance to you on this phase of the project. When we may be of further service to you or should you have any questions, please contact us.

Very truly yours, ARDAMAN & ASSOCIATES, INC.

Florida Registry 5950

Zan C. Bates, P.E. Charles H. Cunningham, P.E.

Senior Engineer Vice President Florida License No. 49917 Florida License No. 38189

THIS ITEM HAS BEEN DIGITALLY

SIGNED AND SEALED BY:

ON THE DATE ADJACENT TO THIS SEAL.

PRINTED COPIES OF THIS DOCUMENT ARE

NOT CONSIDERED SIGNED AND SEALED

AND THIS SIGNATURE MUST BE VERIFIED

ON ANY ELECTRONIC COPIES.

ARDAMAN & ASSOCIATES, INC.

8008 S. ORANGE AVENUE

ORLANDO, FLORIDA 32809

(407) 855-3860

FLORIDA REGISTRY 5950

ZAN C. BATES, P.E. NO 49917

ZCB/CHC/lms 24-60-6430 Bentley Group - Tomoka Farms Landfill PEMB Structure, Port Orange.docx (Geo 2024)

APPROXIMATE

SITE LOCATION

OBTAINED FROM U.S.G.S. QUAD MAP: DAYTONA BEACH, FLORIDA 1952

SITE LOCATION MAP

24-6430

FILE NO.

DRAWN BY:

(PHOTOREVISED 1993)

SECTION 9

RANGE 32 EAST

TOWNSHIP 16 SOUTH

Ardaman & Associates, Inc.

APPROVED BY:

01/08/25

FIGURE:

DATE:

SUBSURFACE SOIL EXPLORATION

PROPOSED PEMB STRUCTURE

TOMOKA FARMS LANDFILL

VOLUSIA COUNTY, FL

N

0 1000 2000

SCALE: (FEET)

BLS

Zan C. Bates, P.E.

Geotechnical, Environmental and

Materials Consultants

T O r l a n d o d w g

P

M

C h r i s D r e w

TH-1

TH-2

T

O

M

O

K

A

L

A

N

D

F

I

R

D

24-6430 2

Materials Consultants

Geotechnical, Environmental and

Ardaman & Associates, Inc.

01/08/25

SUBSURFACE SOIL EXPLORATION

PROPOSED PEMB STRUCTURE

TOMOKA FARMS LANDFILL

VOLUSIA COUNTY, FL

N

0 20 40

SCALE: (FEET)

Zan C. Bates, P.E.

BLS

NOTE: THE AERIAL PHOTOGRAPH FOR THE BORING LOCATION PLAN WAS

OBTAINED FROM GOOGLE EARTH PRO, IMAGERY DATE 05/07/2021.

BORING LOCATION PLAN

LEGEND

STANDARD PENETRATION TEST (SPT) BORING LOCATION

TH

D E

P T

H

20 20

F E

T

N

TH-1

12/18/24

WOH

D E

P T

H F

E

T

-200: 11

25 25

N

TH-2

12/18/24

WOH

1B

3B

3A

2B

2C

4B

4A

1B

WITH SOME SHELL

WITH TRACE SHELL

1B

2A

3B

2C

3A

4A

CONCRETE

HAND

AUGER

-200: 13

-200: 1

HARDPAN-TYPEHARDPAN-TYPE

SOIL BORING PROFILES

24-6430 3

Materials Consultants

Geotechnical, Environmental and

Ardaman & Associates, Inc.

01/08/25

SUBSURFACE SOIL EXPLORATION

PROPOSED PEMB STRUCTURE

TOMOKA FARMS LANDFILL

VOLUSIA COUNTY, FL

Zan C. Bates, P.E.

BLS

LEGEND

-200 PERCENT PASSING NO. 200 SIEVE SIZE (PERCENT FINES)(ASTM D-1140)

STANDARD PENETRATION RESISTANCE IN BLOWS PER FOOTN

FINE SAND WITH SILT (SP-SM)

CLAYEY FINE SAND (SC)

FINE SAND WITH CLAY (SP-SC)

B

C

SOIL DESCRIPTIONS

FINE SAND (SP)1

COLORS

A

SHELL CONTENT

TRACE: <5%

FEW: 5 TO 10%

LITTLE: 15 TO 25%

SOME: 30 TO 45%

MOSTLY: 50 TO 100%

NOTE: 1. UPON COMPLETION OF EACH BORING, THE BOREHOLE WAS BACKFILLED

WITH SOIL CUTTINGS.

2. ALL SPT BORINGS WERE PERFORMED USING AN AUTOMATIC HAMMER

TO THE BORING TERMINATION DEPTH. AUTOMATIC HAMMER N-VALUES

MAY BE CONVERTED TO EQUIVALENT SAFETY HAMMER N-VALUES BY

MULTIPLYING BY 1.24.

WHILE THE BORINGS ARE REPRESENTATIVE OF SUBSURFACE CONDITIONS AT THEIR

RESPECTIVE LOCATIONS AND FOR THEIR RESPECTIVE VERTICAL REACHES, LOCAL VARIATIONS

CHARACTERISTIC OF THE SUBSURFACE MATERIALS OF THE REGION ARE ANTICIPATED AND MAY

BE ENCOUNTERED. THE BORING LOGS AND RELATED INFORMATION ARE BASED ON THE

DRILLER'S LOGS AND VISUAL EXAMINATION OF SELECTED SAMPLES IN THE LABORATORY. THE

DELINEATION BETWEEN SOIL TYPES SHOWN ON THE LOGS IS APPROXIMATE AND THE

DESCRIPTION REPRESENTS OUR INTERPRETATION OF SUBSURFACE CONDITIONS AT THE

DESIGNATED BORING LOCATIONS ON THE PARTICULAR DATE DRILLED.

GROUNDWATER ELEVATIONS SHOWN ON THE BORING LOGS REPRESENT GROUNDWATER

SURFACES ENCOUNTERED ON THE DATES SHOWN. FLUCTUATIONS IN WATER TABLE LEVELS

SHOULD BE ANTICIPATED THROUGHOUT THE YEAR. ABSENCE OF WATER SURFACE DATA IN THE

BORING IMPLIES THAT NO GROUNDWATER DATA IS AVAILABLE, BUT DOES NOT NECESSARILY

MEAN THAT GROUNDWATER WILL NOT BE ENCOUNTERED AT THIS LOCATION OR WITHIN THE

VERTICAL REACHES OF THIS BORING IN THE FUTURE.

UNIFIED SOIL CLASSIFICATION SYSTEM (ASTM D-2487)

SP,SP-SM

SM,SC,CH

GRANULAR MATERIALS-

RELATIVE DENSITY

AUTOMATIC HAMMER

SPT N-VALUE

(BLOWS/FOOT)

VERY LOOSE

LOOSE

MEDIUM DENSE

DENSE

VERY DENSE

LESS THAN 3

3 TO 8

8 TO 24

24 TO 40

GREATER THAN 40

DARK BROWN

GRAYISH BROWN

LIGHT BROWN TO BROWN

STANDARD PENETRATION TEST (SPT) BORING LOCATION

TH

GROUNDWATER LEVEL MEASURED ON DATE DRILLED

APPENDIX

Standard Penetration Test Boring Procedure

STANDARD PENETRATION TEST

The standard penetration test is a widely accepted test method of in situ testing of soils (ASTM D-1586), and Ardaman & Associates generally follows this test method. A 2-foot long, 2-inch O.D.

split-barrel sampler attached to the end of a string of drilling rods is driven 18 or 24 inches into the ground by successive blows of a 140-pound hammer freely dropping 30 inches. The number of blows needed for each 6 inches of penetration is recorded. The sum of the blows required for penetration of the second and third 6-inch increments of penetration constitutes the test result or N-value. After the test, the sampler is extracted from the ground and opened to allow visual examination and classification of the retained soil sample. The N-value has been empirically correlated with various soil properties.

The tests are usually performed at 5-foot intervals. The test holes are advanced to the test elevations by rotary drilling with a cutting bit, using circulating fluid to remove the cuttings and hold the fine grains in suspension. The circulating fluid, which is a bentonitic drilling mud, is also used to keep the hole open below the water table by maintaining an excess hydrostatic pressure inside the hole. In some soil deposits, particularly highly pervious ones, flush-coupled casing must be driven to just above the testing depth to keep the hole open and/or prevent the loss of circulating fluid.

Representative split-spoon samples from the soils are brought to our laboratory in air-tight jars for further evaluation and testing, if necessary.