Attach_12_Subsurface_Exploration_and_Geotech_Engr_Report,_Sept_30,_2011.pdf

Subsurface Exploration and Geotechnical Engineering Report

Proposed Paradise Inn Annex Improvements Mount Rainier, Washington

Prepared for:

Otak, Inc.

September 30, 2011 1794-00

Ash Creek Associates, Inc.

Erwimomcntal and Geotechnical Consultants

3015 SW First A~ nuc Portland. Oregon 97201- 4707

(503) 924- 4704 Portland

(360) 567-3977 Vancouver {503) 943 -6357 Fax www.ashcrcckassoc1ates.com

Subsurface Exploration and Geotechnical Engineering Report

Proposed Paradise Inn Annex Improvements Mount Rainier, Washington

Prepared for:

Otak, Inc.

September 30, 2011 1794-00

Adam Reese, R.G.

Project Geologist, Ash Creek Associates

Stuart Albright, P.E.

Principal Engineer, Ash Creek Associates

Table of Contents

1.0 INTRODUCTION

2.0 PURPOSE, SCOPE, AND PROJECT UNDERSTANDING

2.1 Purpose of Work

2.2 Scope of Ash Creek's Services

3.0 LIMITATIONS OF OUR WORK

4.0 SITE DESCRIPTION AND PROJECT UNDERSTANDING

5.0 GEOLOGIC SETTING

5.1 Seismicity and Earthquake Sources

5.2 Site Seismic Soil Coefficient and Ground Shaking

6.0 SUBSURFACE CONDITIONS

7.0 DISCUSSIONS

8.0 CONCLUSIONS AND RECOMMENDATIONS ......................................................................................... ?

8.1 Permanent Drainage

8.2 Site Preparation

8.3 Excavations and Utilities

8.4 Compaction Recommendations

8.5 Suitable Fill Materials

8.6 Foundations 1

9.0 ADDITIONAL GEOTECHNICAL SERVICES 2

10.0 CLOSING

Figures

1 Site Location Map

2 Site Exploration Plan

Appendix

A Boring Logs

Subsurface Exploration and Geotechnical Report Paradise Inn Annex, Mount Rainier

1.0 Introduction

This report presents Ash Creek Associates, lnc.'s (Ash Creek's) geotechnical exploration and recommendations for foundation improvements for the Paradise Inn Annex located in Mt. Rainier National

Park, Pierce County, Washington (see Figure 1).

2.0 Purpose, Scope, and Proiect Understanding

2.1 Purpose of Work

The purpose of our work was to provide geotechnical engineering recommendations for the design and construction of new foundation elements and foundation dewatering for the Paradise Inn Annex building.

2.2 Scope of Ash Creek's Services

Ash Creek's scope of services for this project included the following:

• A review of general geologic literature and previous geotechnical reports in the project vicinity;

• Surficial reconnaissance;

• Subsurface explorations;

• Geotechnical engineering analyses; and

• Preparation of this report.

3.0 Limitations of Our Work

This work was performed for the exclusive use of Otak, Inc., and their clients and consultants, for specific application to this project and site. Ash Creek performed this work in accordance with generally accepted professional practices in the same or similar related to the nature of the work accomplished, at the time the services were performed. No other express or implied, is made.

4.0 Site Description and Proiect Understanding

Paradise Inn Annex, Mount Rainier north ridge of the Paradise Valley. The site is located at an elevation of approximately 5,400 feet above sea level and approximately 400 feet above the floor of the Paradise Valley below. At depth, the site is underlain by the andesite typical of the Mount Rainier stratovocano. Locally the andesite is overlain by deposits from the Paradise lahar and subsequent pyroclastic deposits.

The Paradise Inn was completed in 1917 and is a timber framed, lodge style building. The structure was expanded with the completion of the annex in 1920. Both buildings feature stacked rubble foundations.

These foundations have generally provided adequate support for the buildings to date, but they are not likely to be able to withstand a design earthquake. As such, one aspect of improvements planned for the site is to provide seismically stable foundations for the historic structure.

The Paradise Inn site is subject to the deepest snow packs in the United States which result in extreme wall and column loads. In addition to the high snow loads, the spring runoff events result in high groundwater and significant surface flow throughout the property. The volume and duration of this melt impacts operations in significant ways.

A previous geotechnical study was conducted on the project site in 2004 and was entitled, "Geotechnical

Exploration at Paradise Inn, Mount Rainier National Park", Northwest Geotech (NGI), Inc., November 22, 2004. The 2004 NGI report pertained to subsurface conditions and engineering recommendations for both the main lodge building and the annex.

The main lodge building underwent foundation repair and seismic upgrade in 2006 and 2007. Construction issues related to excavation and dewatering prompted additional consideration of geotechnical aspects of the annex construction. Ash Creek conducted a review of the NGI report, with conclusions reported in a memorandum entitled "Preliminary Geotechnical Review", dated December 22, 2011. Based upon the review, additional geotechnical exploration was recommended to further refine the understanding of the subsurface conditions and groundwater presence in the vicinity of the annex building.

5.0 Geologic Setting

Geologic Overview. Based upon review of Geologic Studies for the project vicinity, the near ground surface geologic unit underlying the site consists of Holocene-aged deposits of the Paradise lahar (Qvt).

A lahar is a volcanic debris flow consisting of a moving mixture of water and pyroclastic debris originating from a volcanic episode. On the site, these deposits appear as moderately consolidated of and sand, with larger angular particles ranging in size from fine gravel to large boulders. Variable in thickness, this unit has been found at depths of up to 14 in our in the vicinity of the Inn

Annex.

Subsurface Exploration and Geotechnical Engineering Report Paradise Inn Annex, Mount Rainier

At depth, the project site is underlain by Quaternary-aged Volcanic (Qv) rocks, primarily banded or platy andesite. Outcrops of this formation were observed within a few hundred feet to the south and west of the annex. Based upon our boring explorations as well as reviewing other drilling records for the project site, it appears that the andesite formation underlays the building at depths of greater than approximately 14 feet below the ground surface (bgs).

5.1 Seismicity and Earthquake Sources

The seismicity of the Mount Rainier area, and hence the potential for ground shaking, is controlled by three separate fault mechanisms. These include the Cascadia Subduction Zone (CSZ), the mid-depth intraplate zone, and the relatively shallow crustal zone. Descriptions of these potential earthquake sources are presented below.

The CSZ is located offshore and extends from northern California to British Columbia. Within this zone, the oceanic Juan De Fuca Plate is being subducted beneath the continental North American Plate to the east.

The interface between these two plates is located at a depth of approximately 15 to 20 kilometers (km). The seismicity of the CSZ is subject to several uncertainties, including the maximum earthquake moment magnitude (Mw) and the recurrence intervals associated with various Mw earthquakes. (Mw is used by seismologists to measure larger earthquakes and is based on fault displacement and area of fault rupture, while, for smaller earthquakes, the Mw is approximately equal to the familiar Richter Scale Magnitude.)

Anecdotal evidence of previous CSZ earthquakes has been observed within coastal marshes along the

Northwest coast. Sequences of interlayered peat and sands have been interpreted to be the result of large subduction zone earthquakes occurring at intervals on the order of 300 to 500 years, with the most recent event taking place approximately 300 years ago. A definitive study of Northwest seismic hazards completed by Geomatrix (1995) suggests that the maximum earthquake associated with the CSZ is Mw 8 to 9. This is based on an empirical expression relating Mw to the area of fault rupture derived from earthquakes that have occurred within subduction zones in other parts of the world. An Mw 9 earthquake would involve a rupture of the entire CSZ. As discussed by Geomatrix (1995), this has not occurred in other subduction zones that have exhibited much higher levels of historical seismicity than the CSZ and is considered unlikely. For the purpose of this study, an earthquake of Mw 8.5 was assumed to occur within the

The intraplate zone encompasses the portion of the subducting Juan De Fuca Plate located at a depth of approximately 30 to 50 km below western Washington. Very low levels of seismicity have been observed within the intraplate zone in Oregon. However, much levels of within this zone have been recorded in Washington and California.

Geomatrix ( 1995) study and include reasons for this se1sm1c quiescence were ;:,u,M:::;:,1t:u

Columbia, as well as the with the intraplate zone on the data nrnc•rmt,srl rt>nrt:><:t:>nl the in the direction of subduction between the va;:,1,;c:1ue zone.

Subsurface Exp/oration and Geotechnical Engineering Report Paradise Inn Annex, Mount Rainier

The third source of seismicity that can result in ground shaking within the Mount Rainier area is crustal earthquakes occurring within the North American The historical seismicity of crustal earthquakes in western Washington is higher than the seismicity associated with the CSZ and intraplate zones. The 1993 Scotts Mills (Mw 5.6) and Klamath Falls (Mw 6.0) were crustal

5.2 Site Seismic Soil Coefficient and Ground Shaking

The coefficient was determined based upon International 1615.1.5.

upon to blow counts determined during our investigation, we rnr,r,mrr .. ,,nrl design be based upon Class "C." A site classification of "C" equates to a very or rock profile. The above seismic design parameters were developed in accordance with the 2006 IBC using data available from the U.S. Geological Survey based on latitude and longitude for N44.786" and Longitude: W121 The code-level desion should presented in the following table.

Code-Level Seismic Design Parameters

Parameter Value

Site Class C

0.472

Logs of the subsurface explorations have been Included in Appendix A of this report. The attached logs describe the soils encountered during exploration and their various engineering properties. Descriptions are based upon in situ testing, laboratory testing, and field classification of soil samples.

A summary of subsurface conditions encountered within our borings has been provided below.

Asphalt/Gravel Surface. Each of the borings was drilled adjacent to the existing annex building in areas that are presently covered in a thin layer of surface gravel. On the north and east sides of the building, these gravel areas covered (or were co-mingled with) a thin layer of old asphalt. The gravel and asphalt layers were collectively a maximum of 4 inches in thickness.

Surface Fills. Approximately 2 to 5 feet of fill was observed in our borings on the north, east and west sides of the annex building. Fill soils consisted of: medium-dense, slightly moist to wet, dark-brown or yellowish-brown, silty to gravelly sand fill. On the east side of the annex, buried wood debris (timbers) was observed at depths of 3.5 to 4.5 feet bgs.

Clayey or Silty SAND with Gravel, Cobble, and Boulders (Lahar Deposits). Below the surface fills, loose to medium dense, moist to wet, pale brown to orange brown, intermittently mottled, silty or clayey sand soils with angular gravel, cobbles, or boulders were observed. This unit consists of mudflow deposits of the Paradise lahar (approximately 5,000 years ago). This soil unit extends from below the surface fills

(where present) to depths of approximately 5 to 10 feet bgs. In Boring 8-4 on the west side of the annex building, this unit, consisting of large boulders (to 4 feet in diameter} was encountered to the maximum explored depth of 16 feet bgs. Auger refusal was encountered in Boring B-4 at a depth of approximately

7 feet bgs in andesite boulders.

Weakly Consolidated Volcanic Bedrock (Flow Interface or Pyroclastic Deposits). At depths in excess of approximately 5 to 10 feet bgs, a dense to very dense, wet, dark gray, soft/friable bedrock was observed.

This origin of this unit is presumably the scoriaceous surface flow of the bedrock below.

This unit was not encountered in Boring 8-4 to the maximum explored depth of approximately 16 however, rock coring methods were in below a of 7 recovery below 11 feet have been of 11 feet bgs. When encountered, this unit to the maximum

21.5 bgs.

with the mudflow aet)os11ts, of the e1mlnri:>rl was encountered in this

It is

Subsurface and Geotechnlca/ Em1inE,eri11a Paradise Inn Annex, Mount Rainier

Groundwater. At the time of drilling, groundwater was observed in each of the borings at depths of 2 to 3 feet bgs. Groundwater levels at the site are primarily related to snowmelt. Groundwater observations were made in late August 2011, presumably after the seasonal high groundwater level. During periods of the highest snowmelt (late-July to early-August) or during years of greater snowpack, seasonal groundwater levels are anticipated to approach ground surface elevations.

7.0 Discussions

The geotechnical conditions present on this site are quite similar to those encountered during the improvements to the main lodge and construction is likely to be confronted with some of the same challenges. The critical issues to be addressed include excavation in an area underlain by large boulders and ground and surface water control.

In general, the subsurface conditions consist of mudflow deposits (similar to the Mt. Saint Helens flows) overlying bedrock. The mudflow deposits generally occurred as silty sands to sandy silts with varying contents of gravel, cobbles and boulders. Because of the violent nature of the placement of the mudflow deposits, the formation consists of a jumbled up mass of wildly variable soil types. Significant changes over short lateral and vertical distances were encountered in our borings and should be anticipated during construction. Of chief concern is the presence of very large boulders within the matrix. Our borings have encountered boulders of up to 4 feet in diameter. Further, we interpret the exposed rock shelf located at the southeast corner of the building as being a large boulder which appears to be more like ten feet across.

Excavations. Large boulders encountered within localized excavations will likely appear as a bedrock surface. As such, the contractor may encounter what appears to be bedrock at any elevation and any location.

Control of Water. From a water issue standpoint, the conditions are such that shallow groundwater will likely always be present across the site. Surface water can rather easily infiltrate into the mudflow soils where further infiltration is likely slowed or stopped entirely by the lower permeability weathered bedrock.

Water ultimately migrates downhill and erupts as springs, but given the irregular bedrock the flow pathways are anything but direct. manifestations of the mudflow deposits can be highly permeable while adjacent areas may be much less permeable. As such, dewatering using widely spaced wells may have limited effectiveness. We have recommended the installation of a cutoff drain on the upslope of building. This drain be installed in the project to with water construction. Further dewaterinq would also be at the point of excavation. This could be or should be to

Subsurface Exp/oration and Geotechnlcal Engineering Report Paradise Inn Annex, Mount Rainier September 30, 2011 1794,.00

The trench drain combined with improved surface drainage and perhaps some waterproofing of the basement foundations below grade would address the majority of the water intrusion into the basement.

Surface drainage currently ponds water adjacent to the building. Although this issue may persist during spring melt due to inadvertent dams created from unmelted snow, it is important to direct as much water as possible away from the foundations. This should be accomplished with both grade changes and pavement maintenance. Further, some level of waterproofing below grade (such as a membrane system) could be applied. These two systems, coupled with a drain system that will address groundwater are the best lines of defense to limit flow into the basement area.

We have discussed water disposal with the project team. Drainage should be directed to either the existing drainage located north of the building or to the broad slope located southeast and below the building. For the slope disposal, a flow spreader with no surface manifestation should be constructed. This structure should be built as far away from, and as far below, the existing structure as feasible.

Foundation Support. The soils and rock formations encountered are generally suitable for the support of foundations. Deriving support from bedrock is not necessary and does not seem feasible without using deep foundations (micropiles).

From an engineering standpoint, the support for the structure would ideally be transferred to new, designed concrete foundations installed in plane, directly below the existing walls and columns. We are aware that this is less than desirable from a historic preservation standpoint. However, this approach should be evaluated for feasibility. If the existing rubble structures are to be maintained, then new foundations capable of providing eccentric support will need to be constructed.

We understand that for the reconstruction of the main building, eccentric spread footings with stem walls and grade beams were used. We further understand that from a building support standpoint that this approach has been successful. As such, we understand that a similar system may be used. An alternate approach would be to use similar stem walls but to provide support using micropiles.

8.0 Conclusions and Recommendations

Our recommendations are based on our current understanding of the project. The foundation and shoring recommendations should be considered preliminary at this point. as the has not advanced to a at which information can be finalized. As the nature and level of associated with the project progress, Ash Creek should be contacted so that we can

Subsurface Exploration and Geotechnical Engineering Report Paradise Inn Annex, Mount Rainier September 30, 2011 1794-00 or revise our recommendations.

8.1 Permanent Drainage

A significant issue to be addressed through the design of the project is how to resolve groundwater impacts on the building foundation elements. The basement elevation is located below the seasonal groundwater table. As such, it will be necessary to consider the effects of groundwater on the project design.

We recommend installing a cutoff drain on the upslope side of the building. This, plus better surface drainage, and perhaps some waterproofing of the basement foundations below grade would address the majority of the water intrusion into the basement. It would be advantageous to install the cutoff drain before starting excavation in order to provide some level of dewatering for the Contractor. Additional dewatering would also likely be necessary during construction.

As noted, surface drainage currently ponds water adjacent to the building. It is likely not feasible to completely remediate this issue since drainage paths during spring melt are dictated to some extent by snow melt patterns. However, this does not preclude the benefit of maintaining as much positive surface drainage away from the building as possible.

The drainage system should be installed as far below the adjacent foundation as is feasible, up to a maximum of approximately 10 feet below the foundation grade. Such a depth may not be practical to design or construct. We anticipate that the elevation of the drain will ultimately be dictated by the elevation of the outfall and the slope of the outfall pipe.

Based on our discussions with the design team, we anticipate that the outfall will either be directed into the adjacent drainage or will terminate in a surface flow spreader constructed downslope to the southeast.

Surface flow spreaders should be built as far away from, and as far below, the existing structure as feasible so as not to influence groundwater in the vicinity of the building.

8.2 Site Preparation

Ideally, the work at this would be constructed during the driest time of the year. However, due to the high elevation and delayed snow melt, we are aware that the "dry season" at the site is too limited (or perhaps nonexistent) to allow for meaningful amounts of construction. The contractor should anticipate that construction will occur during extended periods of high flow and shallow groundwater.

Removal of Old Pavements, Old Fills, and Other Buried Features. Old and walls, site work. to areas which will tunct1on as

Failure to remove and Fl:::l\lt>mi::mk can result in settlement or other issues within new structures

Subsurface Exploration and Geotechnical Report 8 Paradise Inn Annex, Mount Rainier

8.3 Excavations and Utilities

Subsurface conditions encountered during the site investigation indicate that precautions in utility excavations will be required due to the potential for caving/sloughing within the fill soils underlying the site.

Any excavations deeper than 4 feet should be sloped or shored in accordance with OSHA regulations.

Normally, shoring systems (for excavations less than 20 feet in depth) are contractor designed and installed items. Dewatering of perched groundwater and/or rainwater within trenches and excavations may also be required. The design and implementation of dewatering for trenches and excavations is normally the responsibility of the contractor.

Utilities sensitive to moisture should be placed in watertight conduits. Utility conduits should be bedded in sand or 3/4-inch (minus) sand and gravel within one conduit diameter. Bedding should surround the pipe in all directions. Trench backfill should be lightly compacted within two diameters or 18 inches, whichever is greater, above breakable conduits. The remaining backfill should be compacted to 95 percent of the maximum dry density of the material as determined by ASTM D 1557 for granular/crushed rock backfill.

In general, the materials encountered within the proposed depths of excavation consist of native alluvial soils and weathered bedrock. The blowcounts and drilling action indicate that the soils should be excavatable with a large trackhoe. However, it is possible that hard, resistant layers of less weathered rock could be encountered. Of more significance is the presence of large boulders throughout the soil column.

The contractor should be prepared to remove boulders at any elevation or location throughout the site.

Depending on the size and depth of the proposed excavation, quite large boulders that require techniques consistent with bedrock removal may be encountered.

Temporary excavation slopes may be required in areas where adjacent improvements are located within a horizontal distance equal to the depth of the excavation (measured from the top of the excavation). Short term, temporary excavation slopes within fine-grained soils should not exceed slopes of 1 H: 1 V. The actual steepness allowed during construction should be determined on a case-by-case basis. Shoring, tied-back shoring, or foundation underpinning may be required in areas where sloping excavations cannot be employed due to space constraints and said excavation risks undermining bearing of adjacent foundations.

8.4 Compaction Recommendations

fill construction is not nroconth, the nmnncori that has been in accordance with constructed should be recommendations. Fills be installed in horizontal lifts not 8 inches in rv,mn::>rtari to at least percent of the maximum dry should be determined in accordance with may be reduced to in non-structural

Subsurface and Report Paradise Inn Annex, Mount Rainier September 30, 2011 that are or planter areas. Fills placed over ground that slope in excess of 3H:1V should be keyed and benched into firm soils beneath all topsoil and tree or brush roots.

A summary of recommended compaction specifications is provided in the following table.

Table: Recommended Fill Compaction Specifications

Material I Percent of Maximum Dry Density ASTM D 1557

Structural Fill and T ranch Backfill 92

Landscaping Fill 85

Retaining Wall Backfill 90

Base Rock for Slabs and Pavements 95

8.5 Suitable Fill Materials

Structural Fills During Dry Weather Grading. During dry weather, structural fills may consist of virtually any relatively well-graded soil that is free of debris, organic matter, and high percentages of clay or clay lumps, and that can be compacted to the preceding specifications. However, if excess moisture causes the fill to pump or weave, those areas should be dried and recompacted, or removed and backfilled with compacted granular fill. In order to achieve adequate compaction during wet weather, or if proper moisture content cannot be achieved by drying, we recommend that fills consist of well-graded granular soils (sand or sand and gravel) that do not contain more than five percent material by weight passing the No. 200 sieve.

In addition, it is usually desirable to limit this material to a maximum 6 inches in diameter for ease of compaction and future installation of utilities.

Wet Weather Grading. Because moisture levels are difficult to control in fine-grained soils, and soil drying via aeration is not realistically an option, structural fill constructed during the wet season should consist of clean, durable crushed rock, or clean granular fill. Ideally, structural fill material placed during the wet season will contain less than five percent by weight a standard No. 200 At this wet weather grading conditions are likely to be encountered

Retaining Wall Backfill. Backfill behind

To minimize pressures on retaining walls, we less than five percent content by considerably increase wall fluid pressures.

Working Pad. We recommend that a support of the

Subsurface Exploration and Geotechnical Engineering Paradise Inn Annex, Mount Rainier September 30, 2011 1794-00 of troo_tirr:uninr, material.

\A/t:11i-t1rC1rft:1rf crushed rock backfill with of will

8.6 Foundations

The soils present under the foundations of the existing building appear to be suitable for the support of the proposed structure. Ultimately, these same soils have provided adequate support over the life of the structure. As noted in the discussions section, the best approach to foundation support would be to replace the existing stacked rubble foundations with modern concrete foundations, in plane with the walls and columns. It is our understanding that this approach was selected for use through the value analysis process. Constructing new foundations in plane with the wall does require dismantling the existing rubble stone foundations which we understand presents issues from a historic preservation perspective.

If construction of new foundations in plane is not feasible, then the next most straightforward approach would be to take the approach used for the lodge building. Namely, to provide large spread footings within the crawl space that are capable of resolving the high vertical loads and moments associated with eccentricity with the wall plane.

We have provided design recommendations for spread footings regardless of the location. The subsurface conditions noted within our exploratory borings are such that conventional spread footings will function adequately for individual column loads of less than 500 kips and wall loads of less than 10 kips per lineal foot. For spread footings prepared in accordance with the recommendations provided above, we recommend use of an allowable soil bearing capacity of 4 kips per square foot (KsD for foundation sizing.

The allowable bearing pressures may be increased by 1/3 for short-term seismic and wind loading.

Our analysis indicates that, for foundations designed under the above conditions, anticipated settlements are less than 1 inch and differential settlements between individual footing elements are not expected to exceed approximately 1/2 inch.

Sliding Resistance. For sliding resistance, the soils underlying spread footings can be assumed to have an ultimate coefficient of friction of 0.40. Passive soil pressures can be developed along the sides of footings if the granular backfill is used around footings and the backfill is compacted to at least percent of the material's maximum dry density as determined by D 1557. An equivalent passive fluid weight of

350 pcf can be used for resistance against sliding. The sliding coefficient and passive pressures may be increased by 1/3 for short-term seismic and wind loading.

Micro-Piles. If the additional building cannot be

Micro-piles typically bar installed the

Subsurface Exploration and Geotechn/cal Enaineerina Paradise Inn Annex, Mount Rainier September 30, 2011 1794-00 through then the use of with a contractor-production piles, the micro-pile design and installation methodology should be verified by in situ pull testing. We recommended that a minimum of two test micro-piles be pulled to at least

200 percent of the piles' design working load to verify that the design and installation method conforms to required load-carrying capacity. The maximum verification and proof test loads applied to the micro-pile should not exceed 80 percent of the structural capacity of the micro-pile structural elements.

Our experience with soils similar to those present on site indicates that, due to the presence of gravel soils at depth, there is potential for excessive grout-take within micro-piles. It should be required that micro-pile installation include either permanent casing or pre-grouting and re-drilling to minimize grout-take and loss of pile section following installation; permanent casing can be used to minimize excessive grout loss.

Alternatively, use of rapidly hardening grout to seal anticipated flow channels within the gravels should be considered.

Micro-piles should be constructed such that the pile tip penetrates a minimum of 15 feet into the dense soils underlying the site.

9.0 Additional Geotechnical Services

Prior to installation of the foundation support elements and drainage components, we recommend that Ash

Creek review the final design plans and specifications. This review will allow us to evaluate whether any change in concept may affect the validity of our recommendations, and whether our recommendations have been correctly interpreted. In order to correlate preliminary soil data with the actual soil conditions encountered during construction, and to assess construction conformance to our report, we recommend that

Ash Creek be retained for construction observation of the foundation installation and drainage elements.

10.0 Closing

This report presented Ash Creek's geotechnical engineering evaluation and recommendations for proposed underpinning of the Paradise Inn Annex in Mount Rainier National Pierce County, Washington. We trust this report meets your If you have any questions, or if we can be of further assistance, please call. We look forward to working with in the future.

Subsurface Exp/oration and Geotechnical Engineering Report Paradise Inn Annex, Mount Rainier

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Site Location Map Geotechnical Evaluation

Paradise Inn Annex - Mt. Rainier National Park

Pierce, Washington t~~:~5:;~:,c.'..::~s.~.:~~'.~S, Inc.

Pro1cc1 Number 1794-00

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Sample Descriptions Classification of soils in this report is based on visual field and laboratory observations which include density/consistency, moisture condition, and grain size, and should not be construed to imply field nor laboratory testing unless presented herein.

Visual-manual classification methods of ASTM D 2488 were used as an identification guide.

Soil descriptions consist of the following:

MAJOR CONSTITUENT with additional remarks; color, moisture, minor constituents, density/consistency.

Density/Consistency Soil density/consistency in borings is related primarily to the Standard Penetration Resistance. Soil density/consistency in test pits and Geoprobe® explorations is estimated based on visual observation and is presented parenthetically on test pit and Geoprobe® exploration logs.

Standard SAND and GRAVEL Penetration

Resistance Density in Blows/Foot

Very loose 0-4

Loose 4-10

Medium dense 10- 30

Dense 30- 50 Very dense >50

Moisture Dry Little perceptible moisture.

SI. Moist Some perceptible moisture, probably below optimum.

Moist Probably near optimum moisture content.

Wet Much perceptible moisture, probably above optimum.

Sampling Symbols

BORING AND PUSH-PROBE SYMBOLS

- SplitSpoon

Sonic

Tube (Shelby, Push-Probe) fill Cuttings

Core Run

* No Sample Recovery

SSA Solid Stem Auger

HSA Hollow Stem Auger

MR Mud Rotary

TEST PIT SOIL SAMPLES

Grab

Tube

+~sh

Standard SILT or CLAY Penetration

Resistance Density in Blows/Foot

Very soft 0-2

Soft 2-4 Medium stiff 4-8 Stiff 8 - 15 Very Stiff 15- 30 Hard >30

Minor Constituents Estimated Percentage

Not identified in description 0-5

Slightly (clayey, silty, etc.) 5 - 12

Clayey, silty, sandy, gravelly 12 - 30

Very (clayey, silty, etc.) 30- 50

Key to Exploration Logs Geotechnical Evaluation

Mt. Rainier National Park

Boring Number: B-1

• Ash Creek Associates, Inc Paradise Inn Annex - Mt. Rainier National Park Pro1cct Number 1794-00 Env1ronmentdl and Geotcchrncal Consultanrs

Log6,ed By A. Reese Pierce, Washington Date August 22, 2011 Site Conditions XXX

Dull,ng Contractor Western States

Dn,',ng Egu,pment CME 75, Truck-Mounted

Sampler Type HSA, SPT, Split Spoon

Depth to Water (ArD) 1' 10" v 0 Sudace Elevation -- _c· l V

A Standard Penetration Resistance o_ Q.. Lithologic Description V E (Blow> per ruot)

0 ro V, 10 20 30 40

Asphalt concrete (2") over silty, sandy FILL with some gravel.

-- Fin~ SAND with some fines (clayey); very dark brown (10YR 3/3), moist, very soft.

s- 1--- -- - -- - - ------

~ Clayey SAND with some medium angular gravel; pale brown (10YR 6/3),

- wet, weathered intervals, medium dense.

r

- Partially consolidated, litt volcanic ROCK as scoria or sand; dark grayish/reddish brown ( YR 4/2), wet, very dense.

10- >- Becomes dark gray (5YR 4/1) and weathered. Primarily sand consistency,

- ~ with some fines, variable degree of weathering.

- i .

I I 'I ' 92/11" 15-

- Becomes dark reddish gray (5YR 4/2). Weakly consolidated. tl·l 1

~-i I - I

I - 50/5"

20- C5sJ I I

- Bottom of Boring at 20' 5" BGS. ···-

I

- Installed Piezometer.

I , I

.... lt 1 •·+-

.... , .. + I+· •·· , .. ,. •··•··

.... lj ··H+ f···!·· t·+ ' t·+·

, ...... L .. ,. i·· , .. ,.

....... u I

..... rT , . 'll' ,JJ l ... r

..... , ... , .. , .• j .• H ,.,. ,., . 11::+ ······· , .. , .. , ..

r1rl i---t·-·~····~ "· !····· ,., ..

..... L,.,. !•· , .. !-+· H,·· lltt:•.• , .... ,ii t ll f+ 'll' rt

I I :J j

Ps1gc 1/1

•. Ash Creek Associates, Inc ~ Environmental and Geo1echnical Consultants

Geotechnical Evaluation

Paradise Inn Annex - Mt. Rainier National Park

Pierce, Washington v 0

V _c· ci_ Q_ E V ro 0 V, Lithologic Description

Asphalt concrete (2") over sandy FILL with angular gravel/cobble.

Boring Number: B-2 Project Number 1794-00

Logged By A. Reese

Date August 22, 2011

Srte Conditions XXX

Dnllrng Contractor Western States

Drill,ng Equipment CME 75, Truck-Mounted

Sampler Type HSA, SPT, Split Spoon

Depth to Water (ATD) -2'

Surface Elevation --

..&. Standard Penetration Resistance (Blows per foot)

10 20 30 40

1-lnch organic material lens over silty, fine SAND; reddish brown (5YR 5/3),, , , , , 1 1 1 1 1 1 moist, very soft. ~+-+-++· I I I I I I I I I I I I I I I

10-

Clayey SAND with some fine gravel; pale brown (10YR 6/3) with orange-brown mottling, wet, loose.

Becomes weathered, some medium angular gravel. A melange (lahar).

Partially consolidated volcanic (lightweight) ROCK as scoria/tuff;

dark gray (5YR 4/1 ), wet, very dense.

Becomes more consolidated.

Bottom of Boring at 15' 5" BGS.

A, Ash Creek Associates, Inc.

~ Env1ronme11!d! dnd Gco!cLhnitd! ConC>ultdnb

Geotechnical Evaluation

Paradise Inn Annex - Mt Rainier National Park

Pierce, Washington

] IO

s--

10~

Lithologic Description

Gravel/soil surface.

M ~. Medium SAND with some fines (silt/clay); orange-brown (5YR 5/6), moist, [L'J very dense.

Becomes very dark gray (5YR 3/1 ).

Becomes wef.

~ I BOULDERS/COBBLES (Andesite); dense, wet.

~ SAND with fine to medium ANGULAR GRAVEL (highly weathered);

very dark gray (5YR 3/1) and red, wet, very dense.

~ r Becomes (slightly) more consolidated, as friable volcanic bedrock.

Boring Number: B-3 Pro1ect Number 1794.()0

Logged By A. Reese

Date August 22, 2011

Site Condn1ons XXX Dri:i,ng Contractor Western States

Driii,ng Lgu,pmcnr CME 75, Truck-Mounted

Sarnpier lypc HSA, SPT. Split Spoon

Depth to Wirer (Al D) -3'

Surface f::.:cvdt1on --

..6. Standard Penetration Resistance (Blows per r-oo1)

10 20 30 40

,1

111111 1111/111-++++++-~/-W-

1 ..

15~

~i---------~-J-!-++-t+·++-t++-J--1-+--f--l-C-l-t-l-l--+-, Bottom of Boring at 21.5' BGS.

20--l I I I

I I I \fl

•. Ash Creek Associates, Inc ~ Environmental and Geotechnical Con:.uhanb

Geotechnical Evaluation

Paradise Inn Annex - Mt. Rainier National Park

Pierce, Washington

] IO

Lithologic Description

Gravel/soil surface.

Silty SAND with gravel (Fill); dark yellowish brown (10YR 4/6), moist, meoium dense.

Becomes wet.

SAND/GRAVEL (highly weathered bedrock of friable, light volcanic rock);

dark gray (10YR 4/1 ), wet, very dense.

Becomes very hard drilling. Switched to coring.

Encountered obstruction (boulder or bedrock). Moved -4' south for a second attempt. Found same conditions at -a·. Switched to coring.

BOULDERS in a sand matrix.

Bottom of Boring at 16' BGS.

Installed Piezometer.

Boring Number: B-4 Project Number 1794-00

Logged By A. Reese

Date August 23, 2011

Site Conditions Partly Cloudy

Drilling Contractor Western States

Drilling Equipment CME 75, Truck-Mounted

Sampler ·1ype HSA, SPT, Split Spoon

Depth to Water (ATD) ••

Surface Elevation --

A Standard Penetration Resistance {Blows per Foot)

10 20 30 40

Boring Number: B-5

• Ash Creek Associates, Inc. Paradise Inn Annex - Mt. Rainier National Park Pro1ect Number. 1794-00 Environn,entdl and GeotecflnK:dl Consultanls

Logged By A. Reese Pierce, Washington Date August 23, 2011

S11e Cond,t,ons Partly Cloudy Dri!i,ng Contractor Western States

Drili,ng Egwprnent CME 75, Truck-Mounted Sampler Type. HSA, SPT, Split Spoon Depth to Water (ATD} 2' ti g Surface Elevation --JI,!

l l Lithologic Description A Standard Penetration Resistance (Blows per Foot)

10 20 30 40

Gravel/soil surface.

1,6

- ~ Silty SAND; yellowish-orange brown (5YR 5/6), moist to wet, loose. ~--"

- - Some very dark gray gravel.

'- Becomes very dense and wet. 50/5" s- C?sl GRAVEUROCK FRAGMENTS; very dark gray (1 OYR 3/1 ), wet,

- sandy, very dense.

- ~ SAND and fine to medium GRAVEL; very dark gray (10YR 3/1 ), wet, unconsolidated, very dense.

98/11" 10-

- Becomes more consolidated.

,,- Consolidated rock. I I 50/1"

- - I I I I I I 15-- Bottom of Boring at 14' 1" BGS.

I - J I I - I I ! . I

I ~ I -i I 11 _J_ 20- r i

I i I -i I ' -

I 25--

, I

I

I ...

I

30-··

·- I l I I - I' _,, .. ,-, .. -··

I I I I ...

i i :

I i I

·- I I

11 I Ii ! I i i I Pilgc

.,. Ash Creek Associates, Inc.

~ Enwonmrntal and Geotechrncal Consultants

Geotechnical Evaluation

Paradise Inn Annex - Mt. Rainier National Park

Pierce, Washington

Jl Io

J I Ill Lithologic Description

Gravel surface.

Silty SAND (Fill) with some gravel; dark yellowish brown (10YR 4/4), moist to wet, loose.

Woody debris in fills from 3.5 to 4.5'.

SAND/GRAVEL (weakly consolidated rock); very dark gray (1 OYR 3/1 ), wet, very dense. Becomes very hard drilling.

Easier drilling from 12 to 14'.

Boring Number: B-6 Pro1ec1 Number 1794-00

Logged By A. Reese

Date August 23, 2011

S11e Cond11,ons Partly Cloudy

Driii,ng Contracror Western States

Dolling Equipment CME 75, Truck-Mounted

Sampier Type HSA, SPT, Split Spoon

Depth to Water (AfD) 2.5'

Surface E:evation --

.& Standard Penetration Resistance (Blows per Foot)

84/11"

~~------~--+4++-i-++-++++-+--+-++--+-+-l

Bottom of Boring at 16.5' BGS.