(benedict village - waterfront) hydrologic soil group

Hydrologic Soil Group—Charles County, Maryland(Benedict Village - Waterfront)

Natural ResourcesConservation Service

Web Soil SurveyNational Cooperative Soil Survey

8/23/2013 of 4

4263

560

4263

650

4263

740

4263

830

4263

920

4264

010

4263

470

4263

560

4263

650

4263

740

4263

830

4263

920

4264

010

353190 353280 353370 353460 353550 353640 353730 353820 353910 354000

353190 353280 353370 353460 353550 353640 353730 353820 353910 354000

38° 30' 45'' N76

° 4

1' 2

'' W38° 30' 45'' N

76° 4

0' 2

7'' W

38° 30' 27'' N

76° 4

1' 2

'' W

38° 30' 27'' N

76° 4

0' 2

7'' W

N

Map projection: Web Mercator Corner coordinates: WGS84 Edge tics: UTM Zone 18N WGS840 150 300 600 900

Feet0 50 100 200 300

MetersMap Scale: 1:3,920 if printed on A landscape (11" x 8.5") sheet.

ccimino

Polygon

ccimino

Polygon

ccimino

Polygon

ccimino

Callout

GATEWAY

ccimino

Callout

EVENT FIELD

ccimino

Callout

WATERFRONT

MAP LEGEND MAP INFORMATION

Area of Interest (AOI)Area of Interest (AOI)

SoilsSoil Rating Polygons

A

A/D

B

B/D

C

C/D

D

Not rated or not available

Soil Rating LinesA

A/D

B

B/D

C

C/D

D


Soil Rating PointsA

A/D

B

B/D

C

C/D

D


Water FeaturesStreams and Canals

TransportationRails

Interstate Highways

US Routes

Major Roads

Local Roads

BackgroundAerial Photography

The soil surveys that comprise your AOI were mapped at 1:12,000.

Warning: Soil Map may not be valid at this scale.

Enlargement of maps beyond the scale of mapping can causemisunderstanding of the detail of mapping and accuracy of soil lineplacement. The maps do not show the small areas of contrastingsoils that could have been shown at a more detailed scale.

Please rely on the bar scale on each map sheet for mapmeasurements.

Source of Map: Natural Resources Conservation ServiceWeb Soil Survey URL: http://websoilsurvey.nrcs.usda.govCoordinate System: Web Mercator (EPSG:3857)

Maps from the Web Soil Survey are based on the Web Mercatorprojection, which preserves direction and shape but distortsdistance and area. A projection that preserves area, such as theAlbers equal-area conic projection, should be used if more accuratecalculations of distance or area are required.

This product is generated from the USDA-NRCS certified data as ofthe version date(s) listed below.

Soil Survey Area: Charles County, MarylandSurvey Area Data: Version 6, Mar 9, 2009

Soil map units are labeled (as space allows) for map scales 1:50,000or larger.

Date(s) aerial images were photographed: Apr 14, 2011—Nov 12,2011

The orthophoto or other base map on which the soil lines werecompiled and digitized probably differs from the backgroundimagery displayed on these maps. As a result, some minor shiftingof map unit boundaries may be evident.

Hydrologic Soil Group—Charles County, Maryland(Benedict Village - Waterfront)



8/23/2013Page 2 of 4

Hydrologic Soil Group

Hydrologic Soil Group— Summary by Map Unit — Charles County, Maryland (MD017)

Map unit symbol Map unit name Rating Acres in AOI Percent of AOI

DfA Dodon fine sandy loam, 0to 2 percent slopes

B 40.4 69.4%

MT Mispillion andTransquaking soils,tidally flooded

D 2.2 3.8%

W Water 15.6 26.8%

Totals for Area of Interest 58.3 100.0%

Description

Hydrologic soil groups are based on estimates of runoff potential. Soils areassigned to one of four groups according to the rate of water infiltration when thesoils are not protected by vegetation, are thoroughly wet, and receive precipitationfrom long-duration storms.

The soils in the United States are assigned to four groups (A, B, C, and D) andthree dual classes (A/D, B/D, and C/D). The groups are defined as follows:

Group A. Soils having a high infiltration rate (low runoff potential) when thoroughlywet. These consist mainly of deep, well drained to excessively drained sands orgravelly sands. These soils have a high rate of water transmission.

Group B. Soils having a moderate infiltration rate when thoroughly wet. Theseconsist chiefly of moderately deep or deep, moderately well drained or well drainedsoils that have moderately fine texture to moderately coarse texture. These soilshave a moderate rate of water transmission.

Group C. Soils having a slow infiltration rate when thoroughly wet. These consistchiefly of soils having a layer that impedes the downward movement of water orsoils of moderately fine texture or fine texture. These soils have a slow rate of watertransmission.

Group D. Soils having a very slow infiltration rate (high runoff potential) whenthoroughly wet. These consist chiefly of clays that have a high shrink-swellpotential, soils that have a high water table, soils that have a claypan or clay layerat or near the surface, and soils that are shallow over nearly impervious material.These soils have a very slow rate of water transmission.

If a soil is assigned to a dual hydrologic group (A/D, B/D, or C/D), the first letter isfor drained areas and the second is for undrained areas. Only the soils that in theirnatural condition are in group D are assigned to dual classes.

Hydrologic Soil Group—Charles County, Maryland Benedict Village - Waterfront



8/23/2013Page 3 of 4

Rating Options

Aggregation Method: Dominant Condition

Component Percent Cutoff: None Specified

Tie-break Rule: Higher

Hydrologic Soil Group—Charles County, Maryland Benedict Village - Waterfront



8/23/2013Page 4 of 4

Benedict Village Enhancements Concept Stormwater Management Report November 8, 2013

Appendix H:

Site Photos

North Point Stormwater Management Concept Plan Benedict Site Photos November 08, 2013

Figure 7: Benedict Avenue on the Waterfront.

Figure 8: Benedict Avenue from River’s Edge on the Waterfront.

North Point Stormwater Management Concept Plan Benedict Site Photos November 08, 2013

Figure 9: Remaining portion of Benedict Avenue on Waterfront (Project Ends Here).

Figure 10: Deck at River’s Edge on the Waterfront.

Benedict Village Enhancements Concept Stormwater Management Report November 8, 2013

Appendix I:

Geotechnical Report

HILLIS-CARNES ENGINEERING ASSOCIATES, INC.

Subsurface Exploration & Geotechnical Engineering Services Benedict Waterfront Village Enhancements

Benedict, Charles County, Maryland HCEA Project No. 12524A

Prepared for:

Charles Co. Dept. of Planning and Growth Management P.O. Box 2150

La Plata, Maryland 20646

Corporate Headquarters – Annapolis Junction, MD

Frederick, MD ● Hagerstown, MD ● Salisbury, MD ● Waldorf, MD ● Hollywood, MD ● Owings Mills, MD ● State College, PA ●

Chantilly, VA ● New Castle, DE ● Dover, DE

10975 Guilford Road, Suite A

Post Office Box 241

Annapolis Junction, MD 20701

Baltimore 410-880-4788

DC Metro 301-470-4239

Fax 410-880-4098

www.hcea.com

ENG

INEERIN

G A

SSOC

IATES, IN

C.

June 25, 2013 Charles Co. Dept. of Planning and Growth Management P.O. Box 2150 La Plata, Maryland 20646 Attention: Ms. Cathy Hardy Thompson Re: Subsurface Exploration and Geotechnical Engineering Services

Benedict Waterfront Village Enhancements Benedict, Charles County, Maryland HCEA Project No. 12524A

Dear Ms. Thompson: Hillis-Carnes Engineering Associates, Inc. (HCEA) has completed the geotechnical engineering study for the above-referenced project site that is located in the Benedict section of Charles County, Maryland. The exploration consisted of drilling Standard Penetration Test (SPT) borings, performing field infiltration testing, soil laboratory testing and engineering analyses, and preparing this written report of findings and conclusions. We recommend that construction-monitoring services be performed by HCEA. This will help verify that the project design and construction are consistent with the assumptions made in the analyses and conclusions contained in this report. Boring samples will be stored at our Annapolis Junction, Maryland office for a minimum period of 30 days from the date of this letter. Should you wish the samples to be stored for a longer period of time or to be delivered to you or another party, please advise us. Should you have any questions or require additional information about our report, please contact us. Most sincerely, HILLIS-CARNES ENGINEERING ASSOCIATES, INC.

David G. Patron, P.E. Grant K. Autry, P.E.


TABLE OF CONTENTS

1.0 PURPOSE AND SCOPE ............................................................................................................... 1 2.0 PROJECT CHARACTERISTICS ................................................................................................... 1 3.0 FIELD EXPLORATION .................................................................................................................. 2 4.0 SUBSURFACE CONDITIONS ....................................................................................................... 3 4.1 General Site Geology ................................................................................................... 3 4.2 Surface Coverings ........................................................................................................ 4 4.3 Fill Materials .................................................................................................................. 4 4.4 Natural Materials ........................................................................................................... 4 4.5 Groundwater ................................................................................................................. 5 5.0 EVALUATIONS AND RECOMMENDATIONS .............................................................................. 5 5.1 General Site Preparation Comments ........................................................................... 5 5.2 Fill Selection, Placement and Compaction .................................................................. 6 5.3 Proposed Sign .............................................................................................................. 7 5.4 Proposed Boardwalk and Boat Launch ....................................................................... 8 5.5 Groundwater and Drainage .......................................................................................... 9 5.6 Stormwater Management Areas .................................................................................. 9 5.7 Pavement Areas ......................................................................................................... 11 6.0 RECOMMENDED ADDITIONAL SERVICES ............................................................................. 12 7.0 REMARKS .................................................................................................................................... 13 APPENDIX ........................................................................................................................................... 15

Subsurface Exploration & Geotechnical Engineering Services Benedict Waterfront Village Enhancements Page 1 June 25, 2013


SUBSURFACE EXPLORATION & GEOTECHNICAL ENGINEERING SERVICES BENEDICT WATERFRONT VILLAGE ENHANCEMENTS

BENEDICT, CHARLES COUNTY, MARYLAND HCEA PROJECT NO. 12524A

1.0 PURPOSE AND SCOPE

The purpose of this study was to determine the general subsurface conditions at the boring locations and to evaluate those conditions with respect to the concept and design of foundations for the gateway entrance sign, boardwalk, and other waterfront improvements. This report information will also be used to assist in the design of stormwater management (SWM) facilities and provide general site earthwork recommendations for the proposed construction.

The evaluations and recommendations presented in this report were developed

from an analysis of project characteristics and an interpretation of the general subsurface conditions at the sites of the proposed improvements based on the boring information. The stratification lines indicated on the boring logs represent the approximate boundaries between soil types. In-situ, however, the transitions may be gradual. Such variations can best be evaluated during construction and, if necessary, any minor design changes can be made at that time.

An evaluation of the sites with respect to potential construction problems and

recommendations dealing with the earthwork, and monitoring and testing services during construction are also included. The construction monitoring and testing services are considered necessary to verify the subsurface conditions and to verify the soils-related construction phases are performed properly.

The Appendix contains a summary of the field and laboratory work on which this

report is based. 2.0 PROJECT CHARACTERISTICS

This report covers three project areas or sites. The first one is the Village Gateway area, which is located at the intersection of MD Route 231 Prince Frederick Road and Benedict Avenue. This area is a relatively level and open grass covered area that includes one large evergreen tree in the approximate center of the grass island. A new sign is proposed to be constructed on this grass island. Specific structural loading conditions were not known, but it is expected to exhibit relatively light loads, and it will need to be properly designed to break-away in the event of being struck by roadway vehicles. Very limited grading and no filling are expected to be required at the planned location of the sign.



The second area of study is the Event Field Trail and Boardwalk area located along Benedict Avenue and across the street or east of the St. Francis de Sales Church (at 7185 Benedict Avenue). A paved parking lot, along with a walking path, and a boardwalk extending over a marshy area and connecting to the waterfront are planned in this area. Permeable or porous pavement is being considered for use as SWM in the parking lot. We have also been requested to provide conventional flexible pavement recommendations for the planned parking and driveway areas servicing the Event Field Trail and Boardwalk area. The third study area is the Waterfront Improvements area, which is east of the Benedict Avenue right-of-way limits and immediately northeast and southwest of the River’s Edge restaurant (at 7320 Benedict Avenue). A walking path, and a kayak/boat launch zone or wooden deck are proposed in this area. SWM facilities are also proposed in this area to handle post development site runoff. A site vicinity map showing all three study areas is depicted on the Overall Boring Location Plan (adapted from Benedict Waterfront Village Enhancements plan dated 11/30/12 and provided by Wallace Roberts & Todd, LLC) included in the Appendix of this report. Proposed invert levels of the SWM facilities were not known at the time of this study and were to be based on the results of this study. Structural loading information for the boardwalk, launch zone, and wooden deck features were not known at the time of this study. The structural loads are presumed to be relatively light. Should any of the project characteristics or structural loading conditions be significantly different (or high/heavy) from those outlined above, then this office should be contacted for a re-evaluation of the recommendations contained herein.

3.0 FIELD EXPLORATION A total of 8 Standard Penetration Test (SPT) soil borings were expected to be drilled

at the site. Structural borings are the “B” designated borings. Stormwater management or Infiltration borings are the “I” designated borings.

Boring B-1 was drilled to a depth of 10 ft and located at the location of the proposed

sign in the Village Gateway area (reference Village Gateway Boring Location Plan in the Appendix). Borings B-2 and B-3 were to be drilled to a depth of 20 ft each and were located along the proposed boardwalk alignment extending over the marshy area (reference Event Field Trail and Boardwalk Boring Location Plan in the Appendix). Note that boring B-3 was located in an extremely unstable area that couldn’t support the All-Terrain-Vehicle (ATV) drill rig. Consequently, boring B-3 could not be drilled. Boring B-4 was drilled to a depth of 20 ft and located at the location of the proposed kayak/boat launch or wooden deck area (reference Waterfront Improvements Boring Location Plan in the Appendix). Boring B-4 had to



be offset about 5 ft northwest due to a concrete rubble covered embankment along the Patuxent River shoreline.

Borings I-1 and I-2 were drilled to a depth of 10 ft each and located in the Event

Field Trail area (reference Event Field Trail and Boardwalk Boring Location Plan). As noted on the boring logs these borings were offset from their original locations to keep them out of fair play on the existing ball field. Borings I-3 and I-4 were also drilled to a depth of 10 ft each and located southwest and northeast, respectively, of the River’s Edge restaurant (reference Waterfront Improvements Boring Location Plan) in planned SWM areas. These two borings were also offset as noted on the boring logs to keep them away from a pier entrance and underground utility (I-3) or concrete rubble covered embankment (I-4). What appeared to be a concrete septic tank feature was also located about 15 ft southeast of I-3.

In addition to the performance of SPT borings, falling head permeability or in-

place infiltration tests were performed in offset borings adjacent to borings I-1 and I-2. The purpose of the infiltration testing was to determine the in-situ infiltration rates of the natural soils near anticipated invert levels of the SWM facilities planned at these two boring locations. Note that the presence of fill and shallow groundwater conditions prevented the performance of infiltration testing at boring locations I-3 and I-4. The results of the infiltration rates are presented later in this report.

The approximate boring locations are shown on the above-referenced boring

location plans included in the Appendix. The boring location plans were adapted from the “Existing Features Plans”, dated March 2013 and prepared by NG&O Engineering, Inc. The boring elevations were interpolated from the topographic contours depicted on the Existing Features Plans.

The borings were advanced with hollow-stem augers and the subsurface soils were

sampled at 2.5 ft and 5.0 ft intervals. Samples were taken by driving a 1-3/8 inch I.D. (2-inch O.D.) split-spoon sampler in accordance with ASTM D-1586 specifications. The sampler was first seated 6 inches to penetrate any loose cuttings and then was driven an additional foot with blows of a 140-pound hammer falling 30 inches. The number of hammer blows required to drive the sampler the final foot is designated as the "Penetration Resistance" or "N" value or “SPT” result. The penetration resistance, when properly evaluated, is an index of the soil strength and compression characteristics.

Representative portions of each soil sample were placed in glass jars and

transported to Hillis-Carnes' laboratory. In the laboratory, the samples were examined by the Geotechnical Engineer to verify the driller's field classifications. Laboratory testing including Atterberg limits, mechanical gradation analyses and hydrometer grain size analyses were performed to verify the visual classifications.



Natural moisture content tests were also performed to determine the in-situ moisture contents of select soil samples. The samples were classified in accordance with the Unified Soil Classification System (USCS) and the field classifications were revised where necessary based on the laboratory test results. USDA textural classifications were also used to describe the soil samples at SWM boring locations I-1 through I-4. The USCS and USDA symbols appear on the Boring Logs and the system nomenclature is briefly described in the Appendix.

4.0 SUBSURFACE CONDITIONS Details of the subsurface conditions encountered at the site are shown on the

Records of Soil Exploration (Boring Logs). A brief description of the subsurface conditions and pertinent engineering characteristics of the soils are given below.

Strata divisions shown on the Boring Logs have been estimated based on

examination of the recovered boring samples. In the field, strata changes could occur gradually and/or at slightly different levels than indicated. Also, groundwater conditions indicated on the Boring Logs are those observed during the period of the subsurface exploration. Fluctuations in groundwater levels could occur seasonally and might also be influenced by changes in grading, runoff and infiltration rates, and other influencing factors.

Generalized subsurface conditions based on the results of the borings are discussed in detail in the following report sections. For more specific information on soil and groundwater conditions, please refer to the individual boring logs in the Appendix.

4.1 General Site Geology

Based on a review of the Geologic Map of Charles County (1989) the location of the project sites and city of Benedict is mapped as the Kent Island Formation (upper Pleistocene). This formation is described as mainly fine- to medium-grained, moderately sorted to poorly sorted silty sand, tan to orange, with minor gray silty to sandy dewatered clay.

4.2 Surface Coverings The SPT borings show a topsoil/rootmat thickness ranging from 1 to 2

inches. Thicker depths of organics must be expected in the marshy area and across the green areas of the ball field. The topsoil thickness noted on the Boring Logs should not be used solely to estimate topsoil quantities across each of the project sites.



Very soft subgrade conditions were noted at boring locations B-2 and B-3. In fact, the ground was too unstable to access boring location B-3. This portion of the site appears to be a marshy area.

4.3 Fill Materials

Materials identified as fill were encountered at boring location I-3 and I-4 to a depth of 5 ft at each boring location. Materials labeled as fill exhibit a soil stratification indicating placement by mechanical methods and may include foreign matter. The fill materials were composed primarily of medium dense silty sands (SM) and included smaller amounts of sea shells and gravel.

Please note that test borings are not a definitive method of evaluating the presence of existing fill materials because of the limited hole diameters and the very limited sample sizes obtained in comparison to the areal extent of the site. Therefore, it should be anticipated that fill materials may be encountered in other areas of the project sites.

4.4 Natural Materials The soils encountered generally reflect the description of the materials

described in the geologic references. The soils encountered consisted of silty sands or silty clayey sands (SM), clayey sands (SC), sands (SP-SM), and sands and gravels (GP-SP), and included varying combinations and proportions of silts, clays, sands and gravels, and perhaps sea shells. These granular materials exhibited relative densities of very loose to dense.

4.5 Groundwater

Groundwater was monitored during drilling, at completion and 24 hours after completion of all the borings, except B-2, which was backfilled at completion. Groundwater was detected in all the borings as shallow as the ground surface at boring B-2 (at completion) and extending to a depth of 8 ft in boring I-1 (during drilling). Based on the observed groundwater levels the groundwater elevations appear to be near +1 to 0 or near the elevation of the nearby Patuxent River. A more accurate determination of the hydrostatic water table would require the installation of perforated pipes or piezometers that could be monitored over an extended period of time. The actual level of the hydrostatic water table and the amount and level of perched water should be anticipated to fluctuate throughout the year, depending on variations in precipitation, surface run-off, infiltration, site topography, tidal variations, and drainage.



5.0 EVALUATIONS AND RECOMMENDATIONS The following recommendations have been developed on the basis of the previously

described project characteristics and subsurface conditions. If there are any changes to the project characteristics or if different subsurface conditions are encountered during construction, HCEA should be consulted so that the recommendations of this report can be reviewed and revised, if necessary.

We have separated our geotechnical recommendations for the proposed sign,

boardwalk, and boat launch improvements, roadway areas, and the SWM (or infiltration) facilities.

5.1 General Site Preparation Comments

Any debris or existing structures within the planned sign, boardwalk, boat

launch, roadway, and SWM areas should be entirely removed prior to the initiation of new construction. We suggest that all available information regarding any existing utilities at the sites to be improved be carefully reviewed prior to construction to determine their potential impact on the new construction. Removal should include any underground pipes, utilities, and any other underground structures that might interfere with the new construction. If abandoned underground utilities are to be removed prior to the initiation of construction, provisions should be made in the construction specifications and budget to restore the subgrade to a stable condition. Restoration should include backfilling and proper compaction of the excavation areas. Removal should also include topsoil; unapproved man-placed materials; asphaltic pavement, concrete slabs/pavement, frozen, wet, soft or very loose soils; and any other deleterious materials. These operations should be performed in a manner consistent with good erosion and sediment control practices.

After the initial stripping process is completed, areas of the site to receive fill,

or areas of the site to support a new improvement or structural feature, i.e., new roadway, walk path, or boat launch, should be proofrolled. The proofrolling operations should be performed using a fully-loaded dump truck or another pneumatic-tire vehicle of similar size and weight. The purpose of the proofrolling will be to provide surficial densification and to locate any near-surface pockets of soft or loose soils requiring undercutting. The Geotechnical Engineer or his authorized Engineering Technician should witness the proofrolling operations and determine whether any areas require undercutting and/or stabilization.



5.2 Fill Selection, Placement and Compaction Any material to be used as fill or backfill should be examined, tested and

approved by the Geotechnical Engineer. In general, the on-site soils which are free from organic and other deleterious components can be re-used as general site fill. Materials suitable for various construction purposes can be identified by the Geotechnical Engineer or his authorized Engineering Technician during grading operations.

Moisture conditioning (that is, wetting or drying) of the soils should be

anticipated to achieve proper compaction, particularly if earthwork is performed other than in the summer months. The moisture contents of the soils should be controlled properly to avoid extensive construction delays. If imported fill material is required, those materials should have Unified Soil Classifications of SM or more granular.

All fill should be placed in relatively horizontal 8-inch (maximum) loose lifts

and should be compacted to a minimum of 95 percent of the Standard Proctor (ASTM D-698) maximum dry density. Fill materials in landscape and other non-structural areas should be compacted to at least 90 percent of the Standard Proctor maximum dry density if significant subsidence of the fill under its own weight is to be avoided. Field moisture contents should be maintained within 4 percentage points of the optimum moisture content in order to provide adequate compaction.

Note that due to the potential of shallow groundwater conditions care should

be exercised to prevent destabilization of soils compacted near groundwater levels. Static rolling/compaction should be expected to be used and vibratory rolling only used, as needed, during final rolling passes and as required to achieve the required degree of compaction.

Structural fill should extend a minimum of ten feet beyond structural fill pads.

Fill slopes no steeper than 2(H):1(V) should be used. A sufficient number of in-place density tests should be performed by an experienced Engineering Technician on a full-time basis to verify that the proper degree of compaction is being obtained.

5.3 Proposed Sign

Based on the results of boring B-1 the proposed sign can be supported on a shallow foundation system bearing on approved natural soils, newly placed engineered fill, or a combination thereof. Based on the anticipated structural loads and the general soil conditions encountered, it is recommended that the footing be designed for a net allowable soil bearing pressure of 2500 PSF for support on approved natural soils. To preclude punching shear



failures, the sign footing should be at least 24 inches wide. Since a net soil pressure is specified, the weights of the footing concrete and backfill need not be added to the structural loads when proportioning the footing. The footing should be properly designed and embedded to resist uplift and lateral forces. The bulk weight of the footing overburden soils may be expected to be 125 PCF. Where required for lateral resistance a coefficient of friction of 0.4 may be used between the base of the sign footing and approved natural soil. An equivalent passive fluid weight of 350 PCF may be used for the footing poured against undisturbed, earth formed soils, comprised of approved natural soils. Where man-placed forms are used and removed in footing construction care must be exercised to backfill the void area with thoroughly compacted granular fill to provide for the adequate development of the passive earth pressures.

The footing excavation should be examined and tested by the Geotechnical Engineer or his authorized Engineering Technician prior to the placement of concrete. The purpose of the examination would be to verify that the exposed materials will be capable of supporting the design bearing pressure. If soft or very loose pockets are encountered in the footing excavation, the unsuitable materials should be removed and the footing should be located at a lower firmer elevation. Alternatively, the unsuitable materials could be undercut and replaced with either new granular fill placed and compacted in accordance with the recommendations of Sections 5.1 and 5.2 of this report or with flowable fill, or lean mix or foundation concrete.

The sign footing should be located at depths of at least 2.5 ft (and per local

building codes) below final exterior grades so as to provide adequate protection from frost heave.

5.4 Proposed Boardwalk and Boat Launch It is expected that walk paths and the boat launch area will be comprised of a

soil subgrade or a wooden boardwalk constructed on a soil subgrade. Those portions of the boardwalk extending over the marshy area will be a wooden boardwalk supported on a pile foundation system. Where the boat launch area or boardwalk is a soil subgrade or a wooden boardwalk supported on a soil subgrade it should be supported on approved, firm natural soils, approved existing fill materials or on new compacted fill. The subgrade should be prepared in general accordance with the procedures outlined in Sections 5.1 and 5.2 of this report. The subgrade should be proofrolled to verify stability or delineate any soft or loose areas requiring undercutting and/or stabilization.

Those portions of the boardwalk extending over the unstable marshy area

will require support on a pile foundation system. The most cost effective



system would be comprised of timber piles. Using the results of boring B-2 performed in the marshy area and along the proposed boardwalk alignment, the results of our analyses indicate that a timber pile displaying an average diameter of approximately 9 inches, a minimum tip diameter of 8, and a minimum embedment depth of 20 feet in natural soils may be expected to exhibit a 12 TON working capacity. The piles should be driven to an ultimate capacity of at least 24 TONS. Due to the relatively low working capacity no pile load testing is deemed necessary to perform for this project.

5.5 Groundwater and Drainage Groundwater was encountered in all the borings, but considering most

construction will occur at or close to existing site grades it is not expected to pose problems during the anticipated construction. Any water infiltration resulting from precipitation, surface run-off, or perched water should be able to be controlled by means of sump pits and pumps, or by gravity ditching procedures. If any conditions are encountered which cannot be handled in such a manner, this office should be consulted immediately.

Adequate drainage should be provided at the site to minimize any increases

in the moisture contents of the sign foundation, boardwalk, and boat launch area soils. The site drainage should also be such that run-off onto adjacent properties is controlled properly. The site subgrade should be rolled/sealed and properly graded at the end of each work day to transmit surface runoff to stormwater management areas and minimize degradation of the subgrade materials.

5.6 Stormwater Management Areas

We have evaluated the site subsurface conditions at boring locations I-1 through I-4 drilled in the proposed SWM areas. The following information is provided for planning and design of the stormwater management facilities: 1. Location of seasonal high groundwater table. Groundwater was monitored during drilling and 24 hours after completion of the SWM borings. Groundwater elevations were near elevation +1 to 0. 2. Subsurface Conditions Predicated on visual examination and the results of laboratory testing the USDA textural classifications of the natural soils encountered in the borings were classified as fill, loamy sands and sands. Relative densities were noted to range from very loose to medium dense.



In-situ infiltration testing was performed at locations offset from the I-1 and I-2 boring locations. The results of the infiltration tests are as follows:

Boring

No. Approximate Depth of Test

(ft)

Approximate Test Elevation

Measured In-situ Infiltration Rate

(in/hr) I-1 4 +4 4.00 I-2 4 +2.5 3.25

Based on the results of the borings, the USDA textural laboratory testing,

and the field infiltration testing a design infiltration rate of 3.25 inches per hour may be used for the loamy sand materials.

3. Depth to Bedrock/Decomposed Rock Bedrock or auger refusals indicating the presence of bedrock were not encountered within the depths explored in the four SWM borings for this study. The use of infiltration practices is not acceptable when an infiltration rate of less than 0.52 inches per hour is obtained. Also, the bottom of the facility should not be in fill materials and should be located a minimum of 2 to 4 ft above the seasonally high water table and/or bedrock levels. Based on the subsurface conditions and the results of the infiltration tests in SWM borings I-1 and I-2, and considering the above-outlined criteria, infiltration methods may be used for handling post development site run-off at these 2 boring locations. A design infiltration rate of 3.25 inches may be used for the design of SWM facilities with a bottom level constructed in natural sandy loam materials and at least 2 to 4 feet above a seasonally high groundwater elevation +1. The design invert levels with respect to the seasonally high groundwater elevation should be discussed with the governing local stormwater management agency. Predicated on the presence of fill and shallow groundwater conditions in SWM borings I-3 and I-4 infiltration methods should not be used for handling post development site runoff at these two locations.

5.7 Pavement Areas We understand that pavement may be placed in the Event Field Trail and

Boardwalk parking and driveway areas. The pavement subgrade areas should be prepared in accordance with the recommendations provided in



Sections 5.1 and 5.2 of this report. The pavement subgrades should be proofrolled to verify stability and/or locate any areas of soft or loose soils requiring undercutting and/or stabilization.

Based on the results of borings I-1 and I-2, and empirical soil information, the on-site sandy (SM) materials anticipated at planned roadway subgrade levels may be expected to exhibit a subgrade CBR value of at least 4 for materials compacted to at least 95 percent of the Standard Proctor maximum dry density. It is our judgment with proper implementation of the recommendations contained in this report, and the use of good construction practices (i.e., rolling/sealing and proper grading of subgrade soils at the end of each work day to transmit surface runoff to stormwater management areas and minimize saturation of the subgrade materials) the site subgrade soils will provide suitable support for the proposed pavement sections. The pavement subgrade should be compacted to at least 95 percent of the Standard Proctor maximum dry density. The following pavement sections are recommended:

Passenger Car Areas: The following section can be utilized in areas

where traffic will be primarily automobiles, such as in parking areas. This section has been designed using an estimated design traffic volume (EAL) of 10,000 and a design life of 10 to 20 years.

Thickness (inches) Bituminous Concrete Surface (9.5 or 12.5 mm) 3.0 Bank Run Gravel Base (BRG) 6.0 Approved Subgrade (Minimum CBR = 4)

Passenger Car and Truck Areas: This section can be utilized in more heavy traffic areas, such as driveways that may include trucks and trash collection vehicles. This section has been designed utilizing an estimated design traffic volume (EAL) of 115,000 and a design life of 10 to 20 years. If different traffic volumes are developed during further project design, this office should be notified for a re-evaluation of the pavement section.

Thickness (inches) Bituminous Concrete Surface (9.5 or 12.5 mm) 2.0 Bituminous Concrete Base (19.0 mm) 3.0 Bank Run Gravel Base (BRG) 7.0

Approved Subgrade (Minimum CBR = 4)

All pavement construction (including maximum allowable lift thicknesses) and materials should comply with the applicable requirements of the Maryland State Highway Administration (MDSHA) standards and specifications, and any local standards. Note that



clean sandy subgrade soils, relatively free of fine-grained materials, may experience deep rutting during the paving operations and require raking or leveling of the subgrade soils during the placement of the asphalt in order to ensure that the minimum thickness of asphalt is placed. Rigid Concrete Pavement: For areas where a rigid concrete pavement is to be utilized, i.e., heavy truck traffic or trash collection areas, an 8-inch concrete pavement over 6-inches of graded aggregate (sub)base is recommended.

Joints should be spaced at 20 ft (maximum) intervals. Shrinkage reinforcement consisting of a wire mesh with a steel cross-sectional area of at least 0.032 sq in/ft of width in bout the longitudinal and transverse directions should also be provided. Please note that a compressive strength of 4000 PSI was considered for the concrete. It should also be noted that all the joints should be properly designed and sealed to prevent moisture inflow in the subgrade. Where especially heavy truck traffic is anticipated it is recommended that dowel bars be used. The dowels used should be 1.25-inch diameter bars, 18-inches in length. These dowels should be placed at 12-inches on center.

The above-noted pavement sections are applicable provided that the

subgrade soils for all proposed paved areas are similar materials as considered in our analysis. Should significantly different materials be encountered during stripping and excavation operations, or should the pavement subgrade consist of imported fill materials different from those tested, then this Office should be contacted for a re-evaluation of the proposed pavement sections based on the different materials.

6.0 RECOMMENDED ADDITIONAL SERVICES Additional soil and foundation engineering, testing, and consulting services

recommended for this project are summarized below: Site Preparation and Proofrolling: The Geotechnical Engineer or his authorized

Engineering Technician should examine the site subgrades after they have been stripped and excavated in the planned areas of improvement. The Geotechnical Engineer or his authorized Engineering Technician should determine if any undercutting or in-place densification is necessary to prepare walk paths, roadways, boardwalk or boat launch subgrades for fill placement or for direct support of a wooden boardwalk or pavement sections.



Fill Placement and Compaction: The Geotechnical Engineer or his authorized

Engineering Technician should witness any required filling operations and should take sufficient in-place density tests to verify that the specified degree of fill compaction is achieved. The Geotechnical Engineer or his authorized Engineering Technician should observe and approve borrow materials used and should determine if their existing moisture contents are suitable for achieving the required degree of compaction.

Footing Excavation Examination and Testing: The Geotechnical Engineer or his

authorized Engineering Technician should examine and test the sign footing excavation. He should verify that the design bearing pressure is available and that no loose pockets exist beneath the bearing surfaces of the footing excavation. Based on the results of examination and testing, the Geotechnical Engineer or his authorized Engineering Technician would either approve the bearing surface or recommend that loose or soft soils be undercut to the required bearing materials or undercut and replaced with structural fill, or flowable or lean mix or foundation concrete.

Timber Pile Installation Monitoring: The Geotechnical Engineer or his authorized

Engineering Technician should monitor the installation of the timber piles for the boardwalk construction to verify the piles have been properly installed per the project plans and specifications, and may be expected to exhibit the design working capacity.

7.0 REMARKS This report has been prepared to aid in the evaluation of the site for the proposed

construction. It is considered that adequate recommendations have been provided to serve as a basis for design and preparation of plans and specifications. Additional recommendations can be provided as needed.

These analyses and recommendations are, of necessity, based on the information

made available to us at the time of the actual writing of the report and the on-site surface and subsurface conditions that existed at the time the exploratory borings were drilled. Further assumption has been made that the limited exploratory borings, in relation both to the areal extent of the site and to depth, are representative of conditions across the site.

If subsurface conditions are encountered which differ from those reported herein,

this Office should be notified immediately so that the analyses and recommendations can be reviewed and/or revised as necessary. It is also recommended that:



1. We are given the opportunity to review any plans and specifications in order to comment on the interaction of the soil conditions as described herein and the design requirements.

2. The Geotechnical Engineer or his authorized Engineering Technician is

present at the site during the construction phase to verify installation according to the approved plans and specifications. This is particularly important during excavation, placement, and compaction of fill materials.

Our professional services have been performed, our findings obtained, and our

recommendations prepared in accordance with generally accepted engineering principles and practices. This representation is in lieu of all warranties either implied or expressed. HCEA assumes no responsibility for interpretations made by others based on work or recommendations by us.


APPENDIX Overall Boring Location Plan (site vicinity map) Village Gateway Boring Location Plan Event Field Trail and Boardwalk Boring Location Plan Waterfront Improvements Boring Location Plan Particle Size Distribution Reports (3 pages) Laboratory Test Report (Natural Moisture Contents) Records of Soil Exploration (I-1 thru I-4, B-1, B-2, B-4) Field Classification Sheet

38377.96

US

46735.99

US

0

0

0

0

0

0

Pool

Ruins

Ruins

U.C.

Buffer PlantingEvergreen PlantingRed Maple Planting

VillageGateway

GatewaySignage

Solar UplightsPlantings

Event FieldEvent FieldEvergreen PlantingRed Maple PlantingParking Lot (20 spaces)Overflow Parking

Waterfront PierPlantingSeatingInterpretive PanelsTerraced Steps

OverlookSeatingInterpretive PanelPlantings

OverlookSeatingInterpretive PanelPlantings

Clam Shell/Stone Fines Trail

Boardwalk with Interpretive Panels

Red MaplePlanting

Red MaplePlanting

Natural Surface Trail

Red Maple Planting

Lighting

Red Maple Planting

Concrete Path

Red Maple Planting

Clam Shell/Stone Fines Trail

Lighting

1

Gateway to Event Field Entrance 2a

Event Field Entrance to Waterfront Pier 2b

Waterfront Pier to Chapplear’s Alley 2c

Event Field Trail and Boardwalk3

Waterfront Improvements4

Benedict Ave

MD 231 Prince Frederick Rd

MD 231 Prince Frederick Rd

Bened

ict Ave

A St

A StM

ill Creek Rd

Bene

dict

Ave

Chapplears Alley

Patuxent Pl

Potomac Ave

Hyatt Ave

Wharf Lane

Desoto Ln

50 100 200 300 400 500 feet

N

dpatron

Line

dpatron

Typewritten Text

B-1

dpatron

Line

dpatron

Typewritten Text

I-1

dpatron

Line

dpatron

Typewritten Text

I-2

dpatron

Line

dpatron

Typewritten Text

B-2

dpatron

Line

dpatron

Typewritten Text

B-3

dpatron

Line

dpatron

Typewritten Text

B-4

dpatron

Line

dpatron

Typewritten Text

I-4

dpatron

Line

dpatron

Typewritten Text

I-3

dpatron

Typewritten Text

dpatron

Typewritten Text

(not drilled)

dpatron

Typewritten Text

Overall Boring Location Plan

dpatron

Line

dpatron

Typewritten Text

X

dpatron

Typewritten Text

dpatron

Typewritten Text

dpatron

Typewritten Text

dpatron

Typewritten Text

dpatron

Typewritten Text

dpatron

Typewritten Text

X

dpatron

Typewritten Text

B-4

dpatron

Typewritten Text

dpatron

Typewritten Text

dpatron

Typewritten Text

dpatron

Typewritten Text

dpatron

Typewritten Text

dpatron

Typewritten Text

dpatron

Typewritten Text

dpatron

Typewritten Text

dpatron

Typewritten Text

dpatron

Typewritten Text

dpatron

Typewritten Text

dpatron

Typewritten Text

dpatron

Typewritten Text

dpatron

Typewritten Text

dpatron

Typewritten Text

dpatron

Typewritten Text

X

dpatron

Typewritten Text

I-4

dpatron

Line

dpatron

Line

dpatron

Typewritten Text

Waterfront Improvements Boring Location Plan

dpatron

Typewritten Text

I-3

dpatron

Typewritten Text

River's Edge

dpatron

Typewritten Text

Restaurant

HILLIS-CARNES

ENGINEERING ASSOCIATES, INC.

Annapolis Junction, MD

06/19/13

(no specification provided)

PL= LL= PI=

D90= D85= D60=D50= D30= D15=D10= Cu= Cc=

USCS= AASHTO=

*

Greenish gray silty sand3"2"

1 - 1/2"1"

3/4"3/8"#4#10#40

#100#200

100.0100.0100.0100.0100.0100.0100.0100.0

98.695.930.5

33 38 5

0.1366 0.1277 0.09780.0892

SM A-2-4(0)

Moisture Content: 36.6%

Benedict Waterfront Village

12524A

Material Description

Atterberg Limits

Coefficients

Classification

Remarks

Location: B-2. S-5Sample Number: 1 Depth: 13.5'-15.0' Date:

Client:

Project:

Project No: Figure

SIEVE PERCENT SPEC.* PASS?

SIZE FINER PERCENT (X=NO)

PER

CEN

T FI

NER

0

10

20

30

40

50

60

70

80

90

100

GRAIN SIZE - mm.

0.0010.010.1110100

% +3" % Gravel % Sand % Silt % Clay

0.0 0.0 69.5 30.5

6 in

.

3 in

.

2 in

.1½

in.

1 in

.¾

in.

½ in

.3/

8 in

.

#4 #10

#20

#30

#40

#60

#100

#140

#200

Particle Size Distribution Report

HILLIS-CARNES



06/19/13


PL= LL= PI=

D90= D85= D60=D50= D30= D15=D10= Cu= Cc=

USCS= AASHTO=

*

Reddish brown poorly graded sand with gravel3"2"

1 - 1/2"1"

3/4"3/8"#4#10#40

#100#200

100.0100.0100.0100.0100.0

95.284.572.531.2

4.21.9

NP NP NP

6.7287 4.9181 1.12220.7800 0.4094 0.25110.2064 5.44 0.72

SP A-1-b

Moisture Content: 18.5%


12524A


Atterberg Limits

Coefficients

Classification

Remarks

Location: B-4. S-4Sample Number: 2 Depth: 8.5'-10.0' Date:

Client:

Project:

Project No: Figure



PER

CEN

T FI

NER

0

10

20

30

40

50

60

70

80

90

100

GRAIN SIZE - mm.

0.0010.010.1110100


0.0 15.5 82.6 1.9

6 in

.

3 in

.

2 in

.1½

in.

1 in

.¾

in.

½ in

.3/

8 in

.

#4 #10

#20

#30

#40

#60

#100

#140

#200


HILLIS-CARNES



06/21/13


PL= LL= PI=

D90= D85= D60=D50= D30= D15=D10= Cu= Cc=

USCS= AASHTO=

*

USDA: Brown loamy sand3"2"

1 - 1/2"1"

3/4"3/8"#4#10#40

#100#200

100.0100.0100.0100.0100.0

99.099.097.279.241.325.2

0.6967 0.5320 0.24890.1922 0.0969 0.02530.0091 27.20 4.13

Moisture Content: 5.2%USDA Fractions - Sand: 79.1%, Silt: 16.7%, Clay: 4.2%


12524A


Atterberg Limits

Coefficients

Classification

Remarks

Location: I-1. S-2Sample Number: 3 Depth: 2.5'-4.0' Date:

Client:

Project:

Project No: Figure



PER

CEN

T FI

NER

0

10

20

30

40

50

60

70

80

90

100

GRAIN SIZE - mm.

0.0010.010.1110100


0.0 1.0 73.8 17.8 7.4

6 in

.

3 in

.

2 in

.1½

in.

1 in

.¾

in.

½ in

.3/

8 in

.

#4 #10

#20

#30

#40

#60

#100

#140

#200


Laboratory Test Report Date: June 19, 2013 Project: Benedict Waterfront Village Job #: 12524A

Natural Moisture Content Summary

Sample Moisture Content B-1. S-1. 0.0’-1.5’ 13.7% B-2. S-1. 0.0’-1.5’ 36.3% B-2. S-3. 5.0’-6.5’ 13.6%

B-2. S-5. 13.5’-15.0’ 36.6% B-4. S-1. 0.0’-1.5’ 5.6% B-4. S-3. 5.0’-6.5’ 16.7% B-4. S-4. 8.5’-10.0’ 18.5% I-1. S-2. 2.5’-4.0’ 5.2%

0

5

10

15

20

25

30

10

5

0

-5

-10

-15

-20

D

D

D

D

Brown, dry to moist, loose, fine siltySAND, little clay and fine rootmatter (SM)

Orange Brown, very moist to wet,loose to very loose, fine clayeySAND (SC)

Bottom of Hole at 10.0'

2" Topsoil

Groundwaterencountered at 8.9'

while drilling

Backfilled after 24hrs

7"

8"

8"

10"

13.7 3-4-3

3-4-5

4-4-3

3-2-2

7

9

7

4

HILLIS - CARNESENGINEERING ASSOCIATES, INC.

RECORD OF SOIL EXPLORATION

Project Name Benedict Waterfront Village Boring No. B-1

Location Charles County, Maryland Job # 12524A

SAMPLER

Datum Hammer Wt. 140 lbs. Hole Diameter 6" Foreman T. Carroll

Surf. Elev. 10 ft Hammer Drop 30 in. Rock Core Diameter Inspector

Date Started 6-6-13 Pipe Size 2.0 in. Boring Method HSA Date Completed 6-6-13

GROUND

WATER

CAVE IN

DEPTHSAMPLER TYPE SAMPLE CONDITIONS BORING METHOD

DRIVEN SPLIT SPOON UNLESS OTHERWISE D - DISINTEGRATED AT COMPLETION Dry ft. 7.3 ft. HSA - HOLLOW STEM AUGERS

PT - PRESSED SHELBY TUBE I - INTACT AFTER 24 HRS. 6.8 ft. 7.0 ft. CFA - CONTINUOUS FLIGHT AUGERS

CA - CONTINUOUS FLIGHT AUGER U - UNDISTURBED AFTER HRS. ft. ft. DC - DRIVING CASING

RC - ROCK CORE L - LOST MD - MUD DRILLING

STANDARD PENETRATION TEST-DRIVING 2" O.D. SAMPLER 1' WITH 140# HAMMER FALLING 30": COUNT MADE AT 6" INTERVALS.

Elevation/

Depth

SOILSYMBOLS/SAMPLE

CONDITIONS

DescriptionBoring and Sampling

NotesRec. NM% SPT Blows

N

SPT Blows/Foot

C u r v e

10 30 50

0

5

10

15

20

25

30

0

-5

-10

-15

-20

-25

-30

D

D

D

D

D

D

Brown, very moist, very loose finesilty SAND with fine root matter andorganics (SM)

Gray, wet, very loose to loose, fineto medium silty SAND (SM)

Orange Brown, wet, medium densefine SAND, trace silt and gravel(SP-SM)

Gray/Green, wet, medium densevery fine silty clayey SAND (SM)

Bottom of Hole at 20.0'

2" TopsoilSwampy area


while drilling


8"

11"

10"

14"

18"

15"

36.3

13.6

36.6

WOH/12"-1

2-1-2

5-2-5

7-10-8

3-4-9

10-11-14

1

3

7

18

13

25





SAMPLER




GROUND

WATER

CAVE IN


DRIVEN SPLIT SPOON UNLESS OTHERWISE D - DISINTEGRATED AT COMPLETION 0.0 ft. 1.0 ft. HSA - HOLLOW STEM AUGERS

PT - PRESSED SHELBY TUBE I - INTACT AFTER 24 HRS. ft. ft. CFA - CONTINUOUS FLIGHT AUGERS




Elevation/

Depth

SOILSYMBOLS/SAMPLE

CONDITIONS



N

SPT Blows/Foot

C u r v e

10 30 50

0

5

10

15

20

25

30

0

-5

-10

-15

-20

-25

-30

D

D

D

D

D

D

Brown, dry to moist, dense tomedium dense fine silty SAND,trace gravel (SM)

Reddish brown, wet, medium denseto loose, fine to medium SAND,trace silt and gravel (SP)

Gray/Green, moist, medium densevery fine silty clayey SAND (SM)

Bottom of Hole at 20.0'Boring offset 5 ft northwest off ofrubble embankment.

2" Topsoil


while drilling


7"

5"

10"

14"

18"

18"

5.6

16.7

18.5

5-20-22

5-7-6

9-9-6

8-3-4

5-4-7

8-10-16

42

13

15

7

11

26





SAMPLER




GROUND

WATER

CAVE IN







Elevation/

Depth

SOILSYMBOLS/SAMPLE

CONDITIONS



N

SPT Blows/Foot

C u r v e

10 30 50

0

5

10

15

20

25

30

5

0

-5

-10

-15

-20

-25

D

D

D

D

Brown, moist, medium dense fineSAND, some siltSM/Loamy SAND

Brown, moist to wet, loose, fine tocoarse SAND, trace silt and gravelSP-SM/SAND

Bottom of Hole at 10.0'Boring offset 35 ft northwest off ofballfield.

2" Topsoil


while drilling

Backfilled after 24 hrs

In-situ infiltration pipeset at 4.0'

12"

15"

16"

14"

5.2

3-5-8

4-4-5

9-5-4

6-3-3

13

9

9

6



Project Name Benedict Waterfront Village Boring No. I-1


SAMPLER




GROUND

WATER

CAVE IN



PT - PRESSED SHELBY TUBE I - INTACT AFTER 24 HRS. Dry ft. 5.9 ft. CFA - CONTINUOUS FLIGHT AUGERS




Elevation/

Depth

SOILSYMBOLS/SAMPLE

CONDITIONS



N

SPT Blows/Foot

C u r v e

10 30 50

0

5

10

15

20

25

30

5

0

-5

-10

-15

-20

-25

D

D

D

D

Brown, moist, loose fine SAND,some silt, trace fine root matterSM/Loamy SAND

Orange Brown, wet, medium denseto loose, fine to coarse SAND andGRAVEL, trace siltGP-SP/SAND

Bottom of Hole at 10.0'Boring offset 15 ft south off ofballfield.

2" Topsoil


while drilling


In-situ infiltration pipeset at 4.0'

10"

12"

10"

15"

2-2-5

5-4-4

7-7-6

5-3-5

7

8

13

8





SAMPLER


Surf. Elev. 6.5 ft Hammer Drop 30 in. Rock Core Diameter Inspector


GROUND

WATER

CAVE IN



PT - PRESSED SHELBY TUBE I - INTACT AFTER 24 HRS. Dry ft. 4.5 ft. CFA - CONTINUOUS FLIGHT AUGERS




Elevation/

Depth

SOILSYMBOLS/SAMPLE

CONDITIONS



N

SPT Blows/Foot

C u r v e

10 30 50

0

5

10

15

20

25

30

0

-5

-10

-15

-20

-25

-30

D

D

D

D

Brown, moist, medium dense siltySAND, some sea shellsSM/Fill

Orange Brown, wet, loose, fine tocoarse SAND, trace silt and gravelSP-SM/SAND

Bottom of Hole at 10.0'Boring offset 15 ft northeast due topier entrance and undergroundpipe.

1" Topsoil


while drilling


In-situ infiltration pipenot set due to shallow

groundwater

11"

8"

11"

12"

6-11-13

11-9-9

7-5-5

5-3-5

23

18

10

8





SAMPLER




GROUND

WATER

CAVE IN







Elevation/

Depth

SOILSYMBOLS/SAMPLE

CONDITIONS



N

SPT Blows/Foot

C u r v e

10 30 50

0

5

10

15

20

25

30

0

-5

-10

-15

-20

-25

-30

D

D

D

D

Brown, moist, medium dense finesilty SAND, trace gravel and seashellsSM/Fill

Brown, very moist to wet, mediumdense to loose, fine to coarseSAND, trace silt and gravel, tracesea shellsSP-SM/SAND

Bottom of Hole at 10.0'Boring offset 5 ft northwest off ofrubble embankment.

1" Topsoil


while drilling


In-situ infiltration pipenot set due to shallow

groundwater

8"

11"

16"

12"

3-6-16

6-8-10

15-12-9

6-3-4

22

18

21

7





SAMPLER




GROUND

WATER

CAVE IN







Elevation/

Depth

SOILSYMBOLS/SAMPLE

CONDITIONS



N

SPT Blows/Foot

C u r v e

10 30 50

HILLIS-CARNES ENGINEERING ASSOCIATES, Inc.

10975 Guilford Road, Suite A Annapolis Junction, Maryland 20701 Phone: (410)880-4788 Fax: (410)880-4098

Description of Soils – per ASTM D2487

Major Component Component Type Component Description Symbol Group Name GW Well Graded Gravel Clean Gravels <5%

Passing No. 200 sieve GP Poorly Graded Gravel GM Silty Gravel

Gravels – More than 50% of the coarse fraction is retained on the No. 4 sieve. Coarse = 1” to 3” Medium = ½” to 1” Fine = ¼” to ½”

Gravels with fines, >12% Passing the No. 200 sieve GC Clayey Gravel

SW Well Graded Sand Clean Sands <5% Passing No. 200 sieve SP Poorly Graded Sand

SM Silty Sand

Coarse-Grained Soils, More than 50% is retained on the No. 200 sieve

Sands – More than 50% of the coarse fraction passes the No. 4 sieve. Coarse = No.10 to No.4 Medium = No. 10 to No. 40 Fine = No. 40 to No. 200

Sands with fines, >12% Passing the No. 200 sieve SC Clayey Sand

ML Silt Inorganic CL Lean Clay

Organic silt

Silts and Clays Liquid Limit is less than 50 Low to medium plasticity Organic OL

Organic Clay MH Elastic Silt Inorganic CH Fat Clay

Organic Silt

Fine Grained Soils, More than 50% passes the No. 200 sieve

Silts and Clays Liquid Limit of 50 or greater Medium to high plasticity Organic OH

Organic Clay Highly Organic Soils Primarily Organic matter, dark color, organic odor PT Peat

Proportions of Soil Components Particle Size Identification Component

Form Description Approximate percent

by weight Particle Size Particle dimension

Noun Sand, Gravel, Silt, Clay, etc. 50% or more Boulder 12” diameter or more Adjective Sandy, silty, clayey, etc. 35% to 49% Cobble 3” to 12” diameter Some Some sand, some silt, etc. 12% to 34% Gravel ¼” to 3” diameter Trace Trace sand, trace mica, etc. 1% to 11% Sand 0.005” to ¼” diameter With With sand, with mica, etc. Presence only Silt/Clay (fines) Cannot see particle

Cohesive Soils Granular Soils Field Description No. of SPT

Blows/ft Consistency No. of SPT Blows/ft Relative Density

Easily Molded in Hands 0 – 3 Very Soft 0 – 4 Very Loose Easily penetrated several inches by thumb 4 – 5 Soft 5 – 10 Loose Penetrated by thumb with moderate effort 6 – 10 Medium 11 – 30 Medium Dense Penetrated by thumb with great effort 11 – 30 Stiff 31 – 50 Dense Indented by thumb only with great effort Greater than 30 Hard Greater than 50 Very Dense

Other Definitions:

Fill: Encountered soils that were placed by man. Fill soils may be controlled (engineered structural fill) or uncontrolled fills that may contain rubble and/or debris.

Saprolite: Soil material derived from the in-place chemical and physical weathering of the parent rock material. May contain relic structure. Also called residual soils. Occurs in Piedmont soils, found west of the fall line.

Disintegrated Rock: Residual soil material with rock-like properties, very dense, N = 60 to 51/0”. Karst: Descriptive term which denotes the potential for solutioning of the limestone rock and the

development of sinkholes. Alluvium: Recently deposited soils placed by water action, typically stream or river floodplain soils. Groundwater Level: Depth within borehole where water is encountered either during drilling, or after a

set period of time to allow groundwater conditions to reach equilibrium. Caved Depth: Depth at which borehole collapsed after removal of augers/casing. Indicative of loose

soils and/or groundwater conditions.

(benedict village - waterfront) hydrologic soil group

Documents