Section_G_-_Geotech_Report.pdf

Geotechnical Investigation Project No. 222722SA

DPS K9 Facility February 3, 2023 – Page 1

1.0 INTRODUCTION

This report presents the results of a subsoil investigation carried out at the site of the proposed

Department of Public Safety (DPS) K9 Facility improvements, which is located at 410 West Centennial

Boulevard in Casa Grande, Arizona.

It is understood that construction will consist of a 2,400 square foot K9 building at the existing DPS facility. The proposed building will be single story with slab on grade and masonry or steel frame construction.

Structural loads are expected to be light to moderate and no special considerations regarding settlement tolerances are known at this time. It is assumed that adjacent areas will remain landscaped or paved and that no improvements to existing stormwater retention systems will be required. If not the case please provide a grading and drainage plan for review.

2.0 GENERAL SITE AND SOIL CONDITIONS

2.1 Site Conditions

The proposed new building is expected to be in the center of the existing facility. The DPS facility is bounded on the north by a vacant lot followed by Piper Avenue, on the south by Centennial

Boulevard, on the east by Pinal Avenue (State Route 387), and on the west by Piper Avenue followed by an automotive shop. The site consists of parking lot gravel, grass, concrete pavements, and chain-link fencing.

An existing structure (BSF Shop) borders to the site to the north and a canopied structure borders to the south.

Based on the provided site plan, the existing canopy structure is to remain.

Figure 2.1.1 Site Photo Figure 2.1.2 Site Photo

DPS K9 Facility February 3, 2023 – Page 2

A cursory review of available historical aerial imagery was conducted. Historical aerials prior to 1996 were not available. The southern half of the facility was present by 1996 and the facility was expanded in 2005. It is recommended to obtain and review any Phase I/II Environmental Assessment reports that may be available for a more detailed site history. Refer to the following historical aerial photos:

Figure 2.1.3 – Dated 1996 Figure 2.1.4 – Dated 2005

Figure 2.1.5 – Dated 2014 Figure 2.1.6 – Dated 2022

“Google Earth,” Application. [Application]. Available: Google Earth

2.2 Geologic Conditions

The site is located in between known areas that have undergone considerable subsidence due to groundwater removal. Areas of subsidence are known to produce earth fissuring, which has affected areas within several miles of the site. Subsidence is a basin wide phenomenon that would result in differential elevation changes over long distances, which would not affect the type of buildings proposed for this site. No evidence of earth fissures was observed on the site. Fissure gullies form over subsurface irregularities such as bedrock highs, which cause tensional stresses and differential subsidence. Where such anomalies are not

DPS K9 Facility February 3, 2023 – Page 3 present, subsidence tends to be uniform over a wide area, this having minimal effect on surficial structures.

The closest known active earth fissures are in the Signal Peak Study Area and the Sacaton Butte Study Area, several miles to the east and west of the site, respectively. Based on local experience, subsidence and earth fissures historically have not been a problem in the immediate vicinity of the subject site.

If any cracks, crevasses, or fissures are noted during site excavation this office should be notified immediately. Representatives from this office will then visit the site, assess the feature, and make recommendations regarding restorative measures.

2.3 Seismic Design Parameters

The project area is in a seismic zone that is considered to have low historical seismicity. The seismicity of the Phoenix area has had only three magnitude 3.0 events in over 100 years. Liquefaction is not considered a concern as groundwater exceeds 50 feet below ground surface.

Although borings were not advanced to 100 feet, based on the nature of the subsoils encountered in the borings and geology in the area, Site Class Definition, Class D may be used for design of the structures.

In addition, the following seismic parameters may be used for design (based on ASCE7-16 (IBC 2018), utilizing the ATC Hazard Seismic Design Maps):

Table 2.3.1 Seismic Parameters

MCE1 spectral response acceleration for 0.2 second period, SS: 0.176g

MCE1 spectral response acceleration for 1.0 second period, S1: 0.065g

Site coefficient, Fa: 1.6

Site coefficient, Fv: 2.4

MCE1 spectral response acceleration adjusted for site class, SMS: 0.281g

MCE1 spectral response acceleration adjusted for site class, SM1: 0.155g

5% Damped spectral response acceleration, SDS: 0.188g

5% Damped spectral response acceleration, SD1: 0.104g

NOTE 1: MCE = maximum considered earthquake

2.4 General Subsurface Conditions

Fill was encountered in Boring B-2 consisting of clayey sand to a depth of 0.5 feet. The subsoil conditions at the site generally consist of layers of sandy lean clay, clayey sand, and sandy lean clay to depths

DPS K9 Facility February 3, 2023 – Page 4 of approximately 11.5 to 21.5 feet below existing grades. In addition, trace amounts of gravel and weak degrees of calcareous cementation were noted throughout the profile. The standard penetration resistance test

(SPT) values ranged from 4 to 47 blows per foot (bpf), varying with depth. No groundwater was encountered during this investigation. Based on visual and tactile observation, the shallow surface soils were in a range from to ‘dry to moist’ state at the time of investigation.

Laboratory testing indicates in-situ dry densities of the upper soils ranged from 95.6 to 98.5 pcf with water contents ranging from 4.9 to 8.3 percent at the time of investigation. Liquid limits range from 19 to 30 percent with plasticity indices of 5 to 14 percent. The upper soils exhibit a volume increase (swell) due to wetting of 2.3 percent when compacted to moisture and density levels normally expected during construction. An ‘undisturbed’ sample displayed moderate (4.0%) compression due to incremental loading to a maximum confining load of 3,200 psf and significant (11.3%) additional compression due to inundation with water (hydro-collapse).

3.0 ANALYSIS AND RECOMMENDATIONS

3.1 Analysis

Analysis of the field and laboratory data indicates that subsoils at the site are favorable for the support of the proposed structures on shallow foundations and slab-on-grade construction subject to some remedial earthworks. Some special site preparation will be required with respect to the existing/previous structures and related elements and underground utilities. Given the site development and lack of historical aerials, there is a possibility to uncover potential buried hazards undocumented fills and underground utilities.

Laboratory and field testing indicate that the primary geotechnical concern is the presence of inconsistent relative densities and the potential for additional compression, potentially significant and rapid, due to inundation (hydro-collapse). Secondly, removal of the existing site features (concrete slabs, vegetation, and undocumented fills) will result in disturbance of the upper soils. These conditions could cause excessive settlement resulting in in damage to overlying structures. Accordingly, recommendations are made to over-excavate and re-compact the bearing soils to increase density and reduce the potential for collapse and provide a more uniform bearing matrix. The over-excavated and re-compacted soil will mitigate, but not eliminate the potential for additional settlement if the deeper soils become wet. This will also ensure a uniform bearing condition for the new foundations. Attention must be paid to provide and maintain proper drainage to limit the potential for water infiltration of deeper soils.

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The swell potential of the fine portion of the upper clayey soils is a concern. The potential is strong enough to cause differential movements of slabs-on-grade such as floors, sidewalks, patios but not enough to cause damage to heavier structures. Accordingly, it is paramount to provide proper drainage to limit the potential for water infiltrating under slabs. A minimum slope of at least 5 percent for 10 feet is recommended for unpaved landscaped areas.

Typical recommendations to reduce (not eliminate) the swell potential include reducing the compaction requirements and requiring higher moisture contents during pad preparation. This option reduces capacity of the soil to support the industrial slabs on grade. For this reason, it is recommended to provide at least 12-inches of non-expansive material to be placed directly beneath the conventional building slabs and slabs contiguous to the structure such as door landing and sidewalks.

The native clayey subgrade soils are considered suitable for lime stabilization. As an alternate to placing 12 inches of non-expansive import to complete the building pad, the native soils may be treated with chemical lime slurry (minimum 8 inches) to reduce the plasticity and swell potential to less than 1.5 percent.

Commercial lime slurry is recommended to reduce the environmental concerns for blowing lime dust and to ensure proper hydration and mixing. The specified under slab aggregate base course should not be eliminated.

If this option is considered, it is recommended that a mix design be conducted using the native, subgrade soils and varying amounts of proposed lime to determine an optimum amount. This office should be consulted for preliminary parameters for preliminary estimation purposes. Refer to Section 3.9 for additional details.

Ground water is not expected to be a factor in the design or construction of shallow foundations and underground utilities. Excavation operations should be relatively straightforward although deeper excavations may encounter cemented soils which may impede progress and possibly require the use of heavier equipment.

For any type foundations to perform as expected, attention must be paid to provide proper drainage to limit the potential for water infiltration of deeper soils. It is assumed that the landscape plan will use mostly low water use or "green" desert type plants (xeriscape). It is preferred to keep irrigated plants at least 5 feet away from structures with irrigation schedules set and maintained to run intermittingly. Unpaved planter areas should be sloped at least 5 percent for a distance of at least 10 feet away from the building (or other conveyance means) in accordance with building code requirements. It is understood that this may not be possible due to

ADA maximum slope requirements for the adjacent sidewalks and patios. The slope may be reduced to 2 percent provided extra care is taken to ensure sidewalks and other hardscape features do not create a “dam” that prevents positive drainage away from the buildings, creating a "pond" adjacent to the building. Roof drainage should also be directed

DPS K9 Facility February 3, 2023 – Page 6 away from the building in paved scuppers. Pre-cast loose splash blocks should not be used as they can be dislodged and/or eroded. Roof drains should not be allowed to discharge into planters adjacent to the structure.

It is preferred that they be directed to discharge to pavement (per photo example), retention basins or discharge points located at least 10 feet away from the building.

It is reiterated that shallow spread footings are recommended for the exterior walls and other light interior columns since this is the most economical system available. However, this shallow system relies on the dry strength of the unsaturated native soils. A limited depth of re-compaction is recommended to increase density of the near surface soils that are more likely to encounter seasonal moisture changes, or deeper foundations. The deeper native soils are moisture sensitive and could experience differential settlement if subjected to significant surface water infiltration. Recognizing the need to minimize significant water penetration adjacent to the building perimeter that could detrimentally impact the building foundation, the following additional recommendations are made to protect foundations:

1. Take extra precaution to backfill and compact native soil fill to 95 percent in all exterior wall locations.

2. Avoid utility trenches passing through retention basins leading to the building. If unavoidable, backfill the trench with MAG Section 728 ½-sack CLSM to cut off preferred drainage paths.

3. Avoid placing retention basins or underground storage tanks (USTs) next to building foundations. A distance of at least 10 feet should be maintained between structures and the location of any retention basin maximum fill level and 15 feet from any USTs.

4. Create and maintain positive drainage away from the exterior wall for a minimum of 10 feet.

5. Avoid sidewalks, curbs or other elements that create a dam that could cause water to pond within 5 feet of the perimeter wall.

6. Include no irrigated landscape materials in the first 3 feet next to the building.

7. Between 3 feet and 5 feet, include only landscape materials that can be irrigated with a maximum of 1 gallon per hour emitter heads. Set and maintain irrigation controllers to prevent 24/7 flows.

8. Any landscape materials requiring greater than 1 gallon per hour irrigation, including turf, shall be at least 5 feet from the outside face of the building.

9. All irrigation feeder lines, other than those that supply individual emitters, shall not be placed closer than 5 feet to the building.

For exterior slabs-on-grade, frequent jointing is recommended to control cracking and reduce tripping hazards should differential movement occur. It is also recommended to pin the landing slab to the building floor/stem wall. This will reduce the potential for the exterior slab lifting and blocking the operation of out-swinging doors. Pinning typically consists of 24-inch-long No. 4 reinforcing steel dowels placed at 12-inch centers.

DPS K9 Facility February 3, 2023 – Page 7

3.2 Site Preparation

The entire area to be occupied by the proposed construction should be stripped of all vegetation, debris, rubble, undocumented fills, and obviously loose surface soils. Large tree removal should include the major root ball along with disturbed soils. Carefully remove all concrete and other elements as well as any deleterious materials that may be encountered. If any existing structures are to be removed, they and their foundation elements should be removed in their entirety along with soil disturbed by this activity. Final grades should allow for the placement of 12 inches of non-expansive fill on the building pads.

It is unclear if the existing canopied structure is supported on drilled shaft caissons. If this structure is to be removed, they can be cut off just below grade and remain in place if they do not conflict with any new foundations or utilities. If in conflict, they may be able to be pulled out of the ground and then backfilled with 2 sack concrete slurry. Do not attempt to push them over as that will create a deep void that will require mediation.

Given the relatively small size of the structure and the potential for variable fill placement, the entire proposed building pad should be over-excavated at least 2 feet below proposed footing bottom elevation, or existing grade, whichever is deeper, extending at least 5 feet beyond the footing edges within all footing areas. This may be reduced to 2 feet where conflicts with adjacent structures or utilities. If any buried hazards are encountered, they should be removed, and the resulting excavation widened as necessary to provide access for compaction equipment. This will provide a more uniform bearing condition, reduce the potential for differential settlement, and provide sufficient slab support. A representative of the Geotechnical Engineer should examine the subgrade once sub-excavation is complete and prior to backfilling to monitor removal of deleterious materials. Fill placement and quality should be as defined in the "Fill and Backfill" section of this report.

It is not known whether underground utilities on the site will need to be relocated. If any utility is located within 5 feet of any proposed foundation, relocation and/or abandonment of the utility should be provided. They should either be removed and replaced with engineered fill or abandoned in-place. In the case of manholes and pipelines, it may be possible to abandon them in-place. The tops of manholes should be removed and filled with a weak (~500 psi) cementitious grout. Pipelines larger than 6 inches should be capped and filled with grout. If the contractor decides to abandon the pipes in-place, the onus should be put on him to demonstrate that the trench backfill is adequately compacted. Speedie and Associates should be notified of the circumstance for our review. If removal of a pipeline is not possible, the foundations should be deepened to bear in undisturbed soil so that the zone of influence under the foundation does not encroach on the pipeline and/or trench. This zone is any area below a 45° line drawn down and away from the bottom of the foundation edges.

DPS K9 Facility February 3, 2023 – Page 8

Prior to placing structural fill, the exposed grade should be scarified to a depth of 8 inches, moisture-conditioned to optimum (±2 percent) and compacted to at least 95 percent of maximum dry density as determined by ASTM D-698. Pavement areas should be scarified, moisture-conditioned and compacted in a similar manner.

All exposed cut areas and areas above footing bottom elevation that are to receive floor slab only fill should be scarified 8 inches, moisture conditioned to at least optimum to 3 percent above optimum and lightly but uniformly compacted to 90 but not more than 95 percent of maximum dry density as determined by ASTM D-698.

3.3 Foundation Design

The following bearing capacities can be used for design:

Table 3.3.1 Foundation Bearing Capacities

Structure Foundation

Type

Foundation

Depth (1) Bearing Medium

Bearing

Capacity Comments

Minor Structures Spread 1.5 ft. Compacted Subgrade 1,000 psf 2

Main Structure Spread 1.5 ft.

Min. 2ft

Engineered Fill 2,500 psf 3

Comments:

1. Depth refers to bottom of footing elevation below lowest adjacent finished grade or finished floor for interior footings.

2. Minor structures such as screen walls, trash enclosures, small utility buildings, etc. The bottom of footing excavation should be scarified to a depth of 8 inches, moisture-conditioned to optimum (±2 percent) and compacted to at least 95 percent of maximum dry density as determined by ASTM D-698.

3. Shallow spread footings bearing on minimum 2 feet of engineered fill +8” pre-compacted subgrade extending at least 5 feet beyond the footing edges. Refer Figure 3.3.1.

DPS K9 Facility February 3, 2023 – Page 9

Figure 3.3.1 Foundation Detail – Bearing on Engineered Fill

These bearing capacities refer to the total of all loads, dead and live, and are net pressures. They may be increased one-third for wind, seismic or other loads of short duration. These values may be increased by one-third as the allowable toe pressure for retaining walls. All footing excavations should be level and cleaned of all loose or disturbed materials. Positive drainage away from the proposed buildings must always be maintained.

Continuous wall footings and isolated rectangular footings should be designed with minimum widths of 16 and 24 inches respectively, regardless of the resultant bearing pressure. Lightly loaded interior partitions (less than 800 plf) may be supported on reinforced thickened slab sections (minimum 12 inches of bearing width).

Estimated settlements under design loads are on the order of ½ to 1-inch, virtually all of which will occur during construction. Post-construction differential settlements will be on the order of one-half the total settlement, under existing and compacted moisture contents. Additional localized settlements of the same magnitude could occur if native supporting soils were to experience a significant increase in moisture content.

Positive drainage away from structures and controlled routing of roof runoff must be provided and maintained to prevent ponding adjacent to perimeter walls. Planters requiring heavy watering should not be placed adjacent to or within 5 feet of the building. Care should be taken in design and construction to ensure that domestic and interior storm drain water is contained to prevent seepage. Roof drainage should be directed to paved areas or storm drains. They should not discharge into planters adjacent to the structures.

DPS K9 Facility February 3, 2023 – Page 10

Continuous footings and stem walls should be reinforced to distribute stresses arising from small differential movements, and long walls should be provided with control joints to accommodate these movements. Reinforcement and frequent control joints are suggested to allow slight movement and prevent minor floor slab cracking especially in floor areas to be covered with hard tile.

3.4 Lateral Pressures

The following equivalent fluid lateral pressure values may be utilized for the proposed construction:

Active Pressures

Unrestrained Walls 35 pcf

Restrained Walls 60 pcf

Passive Pressures

Continuous Footings 300 pcf

Spread Footings 350 pcf

Coefficient of Friction (w/ passive pressure) 0.35

Coefficient of Friction (w/out passive pressure) 0.45

All backfill must be compacted to not less than 95 percent (ASTM D-698) to mobilize these passive values at low strain. Expansive soils should not be used as retaining wall backfill, except as a surface seal to limit infiltration of storm/irrigation water. The expansive pressures could greatly increase active pressures.

3.5 Fill and Backfill

Native soils are considered suitable for use in general grading fills and engineered fill under footings but should not be used in the top 12-inches of conventional slab on grade pad fill or as wall backfill.

The top 12-inches of pad fill should be completed with an approved low or non-expansive soil, either approved imported Common Borrow, select onsite soils if verified to meet the imported common fill spec, or Select

Granular soil. If Select Granular soils are used, the 4 inches of under-slab aggregate base may be included as part of the top 12-inches. Otherwise, 12-inches of approved common borrow should be used in addition to the normal 4 inches of aggregate base. Native clayey soils can also be treated with lime. Refer to Section 3.9 for additional recommendations for lime stabilization.

If imported common fill for use in site grading is required, it should be examined by a Soils

Engineer to ensure that it is of low swell potential and free of organic or otherwise deleterious material. In general, the fill should have 100 percent passing the 3-inch sieve and no more than 40 percent passing the #200

DPS K9 Facility February 3, 2023 – Page 11 sieve. For the fine fraction (passing the 40 sieve), the liquid limit and plasticity index should not exceed 30 percent and 10 percent, respectively. It should exhibit less than 1.5 percent swell potential when compacted to 95 percent of maximum dry density (ASTM D-698) at a moisture content of 2 percent below optimum, confined under a 100 psf surcharge, and inundated.

Fill should be placed on subgrade which has been properly prepared and approved by a Soils

Engineer. Fill must be wetted and thoroughly mixed to achieve optimum moisture content, ±2 percent. Fill should be placed in horizontal lifts of 8-inch thickness (or as dictated by compaction equipment) and compacted to the percent of maximum dry density per ASTM D-698 set forth as follows:

A. Building Areas

1. Below footing level 95

2. Below slabs-on-grade (non-expansive soils) 95

3. Below slabs-on-grade (expansive soils) 90-95 (max)

(Not recommended for the top 12-inches of Slab)

B. Pavement Subgrade or Fill 95

C. Utility Trench Backfill 95

D. Aggregate Base Course

1. Below floor slabs 95

2. Below asphalt paving 100

E. Landscape Areas 90

3.6 Utilities Installation

Trench excavations for utilities can be accomplished by conventional trenching equipment.

Trench walls may stand near vertical for the short periods of time required to install shallow utilities although sloughing will likely occur in looser and/or sandier soils requiring laying back of side slopes and/or temporary shoring. Adequate precautions must be taken to protect workmen in accordance with all current governmental regulations.

Backfill of narrow utility trenches above bedding and initial backfill zones may be carried out with native excavated material. This material should be moisture-conditioned, placed in 8-inch lifts and mechanically compacted. Water settling is not recommended. Compaction requirements are summarized in the "Fill and Backfill" section of this report. Native soils do not meet the typical granular bedding and initial backfill (see MAG Standard Specification Section 601.4.4) requirements of large diameter CMP tanks. These materials need to meet MAG Standard Specification Section 601 or the drainage engineers design and manufacture recommendations.

DPS K9 Facility February 3, 2023 – Page 12

3.7 Slabs-on-Grade

To facilitate fine grading operations and aid in concrete curing, a 4-inch-thick layer of granular material conforming to the gradation for Aggregate Base (A.B.) as per M.A.G. Specification Section 702 should be utilized beneath the slab. Dried subgrade soils must be re-moistened prior to placing the aggregate base if allowed to dry out, especially if fine-grained soils are used in the top 12-inches of the pad.

The native soils can store a significant amount of moisture, which could increase the natural vapor drive through the slab. Accordingly, if moisture sensitive flooring and/or adhesive are planned, the use of a vapor barrier or low permeability concrete directly under the slab is recommended. Vapor barriers should be a minimum 15-mil thick polyolefin (or equivalent), which meets ASTM E 1745 Class A specifications.

Vapor barriers do increase the potential for slab curling and water entrapment under the slab. Accordingly, if a vapor barrier is used, additional precautions such as low slump concrete, frequent jointing and proper curing will be required to reduce curling potential and detailed to prevent the entrapment of outside water sources.

3.8 Asphalt Concrete Pavement

If earthwork in paved areas is carried out to finish subgrade elevation as set forth herein, the subgrade will provide adequate support for pavements. The location designation is for reference only. The designer/owner should choose the appropriate sections to meet the anticipated traffic volume and life expectancy. The section capacity is reported as daily ESALs, Equivalent 18-kip Single Axle Loads. Typical heavy trucks impart 1.0 to 2.5 ESALs per truck depending on load. It takes approximately 1,200 passenger cars to impart 1 ESAL.

Pavement Design Parameters:

Assume: One 18-kip Equivalent Single Axle Load (ESAL)/Truck

Life: 20 years

Subgrade Soil Profile:

% Passing #200 sieve: 46% average

Plasticity Index: 14% average k: 150 pci (assumed)

R value: 31 (per ADOT tables)

MR: 18,400 (per AASHTO design)

DPS K9 Facility February 3, 2023 – Page 13

Table 3.8.1 Pavement Sections

Area of Placement

Flexible (AC Pavement) Rigid (PCC Pavement)

Thickness Daily 18-kip

ESALs

Thickness Daily 18-kip

ESALs AC (0.39) ABC (0.12) PCCP

Auto Parking, Light Duty 2.0" 4.0" 2 5.0" 8

Main Drives, Fire

Lanes, Heavy Duty

3.0" 4.0" 11 6.0" 21

3.0" 6.0" 25 7.0" 46

Notes:

1. Designs are based on AASHTO design equations and ADOT correlated R-Values.

2. The PCCP thickness is increased to provide better load transfer and reduce potential for joint & edge failures. Design PCCP per ACI 330R.

3. Full depth asphalt or increased asphalt thickness can be increased by adding 1.0-inch asphalt for each 3 inches of base course replaced.

These designs assume that all subgrades are prepared in accordance with the recommendations contained in the "Site Preparation" and "Fill and Backfill" sections of this report, and paving operations are carried out in a proper manner. If pavement subgrade preparation is not carried out immediately prior to paving, the entire area should be proof-rolled at that time with a heavy pneumatic-tired roller to identify locally unstable areas for repair.

Pavement base course material should be aggregate base per M.A.G. Section 702

Specifications. Asphalt concrete materials and mix design should conform to M.A.G. 710. It is recommended that a ½-inch or ¾-inch mix designation be used for the pavements. The actual mix design may be dependent on the selected pavement section and the specified minimum lift thicknesses for the different types of mixes.

Follow M.A.G. Section 710 for recommended minimum lift thicknesses. Pavement installation should be carried out under applicable portions of M.A.G. Section 321 and municipality standards. The asphalt supplier should be informed of the pavement use and be required to provide a mix that will provide stability and be aesthetically acceptable. Some of the newer M.A.G. mixes are very coarse and could cause placing and finish problems. A mix design should be submitted for review to determine if it will be acceptable for the intended use.

For sidewalks and other areas not subjective to vehicular traffic a 4-inch section of concrete will be enough. For trash and dumpster enclosures a thicker section of 6 inches of concrete is recommended.

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Portland Cement Concrete Pavement must have a minimum 28-day flexural strength 550 psi

(compressive strength of approximately 3,700 psi). It may be cast directly on the prepared subgrade with proper compaction (reduced) and the elevated moisture content as recommended in the report. Lacking an aggregate base course, attention must be paid to using low slump concrete and proper curing, especially on the thinner sections. No reinforcing is necessary. Joint design and spacing should be in accordance with ACI recommendations. Construction joints should contain dowels or be tongue-and-grooved to provide load transfer. Tie bars are recommended on the joints adjacent to unsupported edges. Maximum joint spacing in feet should not exceed 2 to 3 times the thickness in inches or exceed ACI 330R recommendations. Joint sealing with a quality silicone sealer is recommended to prevent water from entering the subgrade allowing pumping and loss of support.

Proper subgrade preparation and joint sealing will reduce (but not eliminate) the potential for slab movements (thus cracking) on the expansive native soils. Frequent jointing will reduce uncontrolled cracking and increase the efficiency of aggregate interlock joint transfer.

3.9 Lime Stabilization

As an alternative to placing 12 inches of non-expansive import to complete the building pad, the native soils may be treated with chemical lime slurry (LSS) to reduce the plasticity and swell potential to less than 1.5 percent. A minimum of 8 inches of lime-stabilized soil is recommended under slabs-on-grade plus 4 inches of ABC. Commercial lime slurry is recommended to reduce the environmental concerns for blowing lime dust and to ensure proper hydration and mixing. Depending on the percentage of lime used and its reaction with the native clays, cementing action could increase the subgrade support capacity, improving the load carrying capacity of the floor slab. The specified underslab aggregate base course should not be eliminated.

Lime may also be used to stabilize subgrade soils in vehicle drive and parking areas provided that a mix design is performed to determine if the native soils will react with the lime. There can be a substantial reduction in aggregate base thickness (up to full replacement) for a given traffic volume when the subgrade is treated with lime. Correspondingly, the capacity can be greatly increased. There have been reports of pavement surfacing cracking on thin pavement sections where lime is used. Accordingly, proper subgrade preparation below the lime treated soils will be required to reduce (not eliminate) this potential. This includes increasing the moisture content to at least optimum to 3 percent above and limiting compaction to 90 to 95 percent to a depth of at least 6 inches. This can be accomplished in-place by deep mixing, or if not possible with the equipment used, removing the layer to be treated and preparing the subgrade prior to placing the stabilized base course. The surface of the treated grade should be sealed with an asphalt prime coat to act as a

DPS K9 Facility February 3, 2023 – Page 15 curing agent and prevent the surface from drying prior to installing the pavement. It is also recommended to provide at least 2+ inches on AB on top of the LSS prior to paving. This will provide a layer of unbound material that can be used to fine grade the parking lot (less re-working of the LSS) and to provide an interlayer to further reduce the reflective cracking. A minimum LSS section of 6 inches is recommended.

The application of lime and soil stabilization should be carried out by a contractor experienced in this type of work. Consideration may be given to use of slurry rather than dry application since dusting is a concern. Use of lime slurry will also reduce the amount of loss and provide consistent coverage. This technology is locally available and is currently being used on recent projects. A mix design study would be required to determine the amount of lime required to reduce plasticity and/or increase strength. All lime stabilization work should be carried out in accordance with M.A.G. Section 309 including using a minimum 5 percent lime to prevent reversion.

4.0 GENERAL

The scope of this investigation and report includes only regional published considerations for seismic activity and ground fissures resulting from subsidence due to groundwater withdrawal, not any site-specific studies. The scope does not include any considerations of hazardous releases or toxic contamination of any type.

Our analysis of data and the recommendations presented herein assume that soil conditions do not vary significantly from those found at specific sample locations. Our work has been performed in accordance with generally accepted engineering principles and practice; this warranty is in lieu of all other warranties expressed or implied.

APPENDIX

FIELD AND LABORATORY INVESTIGATION

SOIL BORING LOCATION PLAN

SOIL LEGEND

LOG OF TEST BORINGS

TABULATION OF TEST DATA

CONSOLIDATION TEST

MOISTURE-DENSITY RELATIONS

SWELL TEST DATA

FIELD AND LABORATORY INVESTIGATION

On January 10, 2023, soil test borings were drilled at the approximate locations shown on the attached

Soil Boring Location Plan. All exploration work was carried out under the full-time supervision of our staff engineer, who recorded subsurface conditions and obtained samples for laboratory testing. The soil borings were advanced with a truck-mounted CME-75 drill rig utilizing 7-inch diameter hollow stem flight augers.

Detailed information regarding the borings and samples obtained can be found on an individual Log of Test

Boring prepared for each drilling location.

Laboratory testing consisted of moisture content, dry density, grain-size distribution, and plasticity

(Atterberg Limits) tests for classification and pavement design parameters. Remolded swell tests were performed on samples compacted to densities and moisture contents expected during construction.

Compression tests were performed on a selected ring sample to estimate settlements and determine effects of inundation. All field and laboratory data are presented in this appendix.

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SOIL BORING

LOCATION PLAN

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B-1

B-2

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3331 E. WOOD ST. PHOENIX, ARIZONA 85040 (602) 997-6391

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GEOTECHNICAL/ENVIRONMENTAL/MATERIALS ENGINEERS

AutoCAD SHX Text N

SW

PEAT, HUMUS, SWAMP SOILS WITH

HIGH ORGANIC CONTENTS

GRAVELS WITH

FINES

(LITTLE OR NO FINES)

CLEAN

GRAVELS

HIGHLY ORGANIC SOILS

SILTS

AND

CLAYS

SILTS

AND

CLAYS

MORE THAN 50% OF

COARSE FRACTION

PASSING ON NO. 4

SIEVE

SAND

AND

SANDY

SOILS

MORE THAN 50% OF

COARSE FRACTION

RETAINED ON NO. 4

SIEVE

GRAVEL

AND

GRAVELLY

SOILS

MORE THAN 50% OF

MATERIAL IS

SMALLER THAN NO.

200 SIEVE SIZE

FINE

GRAINED

SOILS

MAJOR DIVISIONS

LIQUID LIMIT

GREATER THAN 50

LIQUID LIMIT

LESS THAN 50

(APPRECIABLE AMOUNT

OF FINES)

SANDS WITH

FINES

MH

OL

CL

ML

SC

SM

SP

WELL-GRADED GRAVELS, GRAVEL -

SAND MIXTURES, LITTLE OR NO FINES

TYPICAL

LETTERGRAPH

SYMBOLS

ORGANIC CLAYS OF MEDIUM TO HIGH

PLASTICITY, ORGANIC SILTS

INORGANIC CLAYS OF HIGH

PLASTICITY

(LITTLE OR NO FINES)

CLEAN SANDS

(APPRECIABLE AMOUNT

OF FINES)

MORE THAN 50% OF

MATERIAL IS

LARGER THAN NO.

200 SIEVE SIZE

COARSE

GRAINED

SOILS

INORGANIC SILTS, MICACEOUS OR

DIATOMACEOUS FINE SAND OR SILTY

SOILS

ORGANIC SILTS AND ORGANIC SILTY

CLAYS OF LOW PLASTICITY

INORGANIC CLAYS OF LOW TO

MEDIUM PLASTICITY, GRAVELLY

CLAYS, SANDY CLAYS, SILTY CLAYS,

LEAN CLAYS

INORGANIC SILTS AND VERY FINE

SANDS, ROCK FLOUR, SILTY OR

CLAYEY FINE SANDS OR CLAYEY

SILTS WITH SLIGHT PLASTICITY

CLAYEY SANDS, SAND - CLAY

MIXTURES

SILTY SANDS, SAND - SILT MIXTURES

POORLY-GRADED SANDS, GRAVELLY

SAND, LITTLE OR NO FINES

WELL-GRADED SANDS, GRAVELLY

SANDS, LITTLE OR NO FINES

CLAYEY GRAVELS, GRAVEL - SAND -

CLAY MIXTURES

SILTY GRAVELS, GRAVEL - SAND -

SILT MIXTURES

POORLY-GRADED GRAVELS, GRAVEL

- SAND MIXTURES, LITTLE OR NO

FINES

PT

OH

CH

GC

GM

GP

GW

DESCRIPTIONS

NOTE: DUAL OR MODIFIED SYMBOLS MAY BE USED TO INDICATE BORDERLINE SOIL

CLASSIFICATIONS OR TO PROVIDE A BETTER GRAPHICAL PRESENTATION OF THE SOIL

Very Soft Soft Firm Stiff

Very Stiff Hard

0 - 2 2 - 4 5 - 8

9 - 15 16 - 30

> 30

0 - 0.25

0.25 - 0.5

0.5 - 1.0

1 - 2 2 - 4 > 4

Very Loose Loose

Medium Dense Dense

Very Dense

0 - 4 5 - 10

11 - 30 31 - 50

> 50

Clays & Silts Blows/Foot Strength (tons/sq ft) Sands & Gravels Blows/Foot

CONSISTENCY RELATIVE DENSITY

0.075 0.420 2.000

4.75

0.42 2.00 4.75

#200 #40 #10

#4 0.75"

#40 #10 #4

0.75" 3"

3"

12"

12"

36" mmmm Lower Limit Upper Limit

PARTICLE SIZE

MATERIAL

SIZE

SANDS

Fine

Medium Coarse

GRAVELS

Fine

Coarse

COBBLES

BOULDERS

Sieve Size Sieve Size

U.S. Standard Clear Square Openings

80 100 Liquid Limit

CL-ML

CL

20 40 60

CH

B -Line

A-Line

ML & OL

MH & OH

P lasticity Index

A grab sample taken directly from auger flights.

A grab sample taken from auger spoils or from bucket of backhoe.

Standard Penetration Test (ASTM D-1586) Driving a 2.0 inch outside diameter split spoon sampler into undisturbed soil for three successive 6-inch increments by means of a 140 lb. weight free falling through a distance of 30 inches. The cumulative number of blows for the final 12 inches of penetration is the Standard Penetration Resistance.

Driving a 3.0 inch outside diameter spoon equipped with a series of 2.42-inch inside diameter, 1-inch long brass rings, into undisturbed soil for one 12-inch increment by the same means of the Spoon Sample. The blows required for the 12 inches of penetration are recorded.

Standard Penetration Test driving a 2.0-inch outside diameter split spoon equipped with two 3-inch long, 3/8-inch inside diameter brass liners, separated by a 1-inch long spacer, into undisturbed soil by the same means of the Spoon Sample.

A 3.0-inch outside diameter thin-walled tube continuously pushed into the undisturbed soil by a rapid motion, without impact or twisting (ASTM D-1587).

Driving a 2.0-inch outside diameter "Bullnose Penetrometer" continuously into undisturbed soil by the same means of the spoon sample. The blows for each successive 12-inch increment are recorded.

DESCRIPTION

Auger SampleAS

BS Large Bulk Sample

S Spoon Sample

RS Ring Sample

LS Liner Sample

ST Shelby Tube

Continuous Penetration Resistance

DESIGNATION

SAMPLE

SOIL LEGEND

Very Loose Brown CLAYEY SAND (SC-Dry to Moist) with Trace Gravel

Dense Light Brown SILTY, CLAYEY SAND (SC/SM-Dry to Moist) with Trace Weak Calcareous Cementation

Dense Light Brown CLAYEY SAND (SC-Dry to Moist) with Trace Gravel, Weak Calcareous Cementation

End of Boring

2.5

5.0

6.0

11.5

5.0

7.5

11.5

S-1

BS-2

RS-3

S-4

NT

NT

98.5

NT

NT

NT

8.3

NT

Resilient Drilling O. Mariscal

Date

Boring Date:

CME-75

222722SA

N/A

NT = Not Tested

R. Bainum

Boring Type:

1-10-23

Contractor:

Field Engineer/Technician:

Hour

Rig Type:

Surface Elevation:

Water Level

DPS K9 Facility

D ep th of

Sa m pl e

N at ur al

W at er C on te nt

In -p la ce

D ry

D en si ty

(P .C

.F .)Hollow Stem Auger

Boring Date:

Resistance Penetration

Project No.:

410 West Centennial Boulevard

Free Water was Not Encountered

BlowsSa m pl e

Driller:

N um be r

Casa Grande, Arizona

Visual Classification 0 per Foot

D ep th (f ee t)

G ra ph ic

Lo g

B-1Log of Test Boring Number:

Depth

_S P

E E

D

IE

2S

A .G

P J

G E

N G

E O

.G D

T

/3 0/

FILL: Brown CLAYEY SAND (SC-Dry to Moist) with Little Gravel, Trace Asphalt Pieces

Medium Dense Brown CLAYEY SAND (SC-Dry to Moist) with Trace Gravel

Medium Dense Brown SILTY, CLAYEY SAND (SC/SM-Dry to Moist) with Weak Calcareous Cementation

Hard Light Brown SANDY LEAN CLAY (CL-Dry to Moist) with Trace Gravel, Weak Calcareous Cementation

Very Stiff

Hard

End of Boring

2.0

6.5

11.5

16.5

21.5

0.5

5.0

7.0

21.5

RS-1

S-2

S-3

S-4

S-5

95.6

NT

NT

NT

NT

4.9

NT

NT

NT

NT

Resilient Drilling O. Mariscal

Date

Boring Date:

CME-75

222722SA

N/A

NT = Not Tested

R. Bainum

Boring Type:

1-10-23

Contractor:

Field Engineer/Technician:

Hour

Rig Type:

Surface Elevation:

Water Level

DPS K9 Facility

D ep th of

Sa m pl e

N at ur al

W at er C on te nt

In -p la ce

D ry

D en si ty

(P .C

.F .)Hollow Stem Auger

Boring Date:

Resistance Penetration

Project No.:

410 West Centennial Boulevard

Free Water was Not Encountered

BlowsSa m pl e

Driller:

N um be r

Casa Grande, Arizona

Visual Classification 0 per Foot

D ep th (f ee t)

G ra ph ic

Lo g

B-2Log of Test Boring Number:

Depth

_S P

E E

D

IE

2S

A .G

P J

G E

N G

E O

.G D

T

/3

B-1 BS-2 BULK 0.0 - 5.0 NT NT 45.5 70 92 98 100 30 16 14 SC CLAYEY SAND

B-1 RS-3 RING 5.0 - 6.0 8.3 98.5 46.0 83 98 100 100 19 14 5 SC-SM SILTY, CLAYEY SAND

B-2 RS-1 RING 1.0 - 2.0 4.9 95.6 NT NT NT NT NT NT NT NT

U

NI

FI

ED

S O

IL

C

LA

SS

IF

IC

A

TI

O N

DESCRIPTION

SPECIMEN

TE

ST

P

IT

N

UM

B

ER

PL

A

ST

IC

IT

Y

IN

D

EX

SA

M

PL

E

N

UM

B

ER

SA

M

PL

E

TY

PE

ATTERBERG

LIMITS

N

AT

U R

AL

W

A

TE

R C

O

NT

EN

T

(P er ce nt o f D ry W ei gh t)

IN

-P

LA

CE

D R

Y

DE

N

SI

TY

LI

Q

U

ID

L

IM

IT

PL

A

ST

IC

L

IM

IT

SO

IL

B O

R

IN

G o r

TABULATION OF TEST DATA

PARTICLE SIZE DISTRIBUTION

(Percent Finer)

1 1

DPS K9 Facility 410 West Centennial Boulevard Casa Grande, Arizona Project No. 222722SASheet of

(P ou nd s

Pe r C ub ic

F oo t)

#2

S

IE

VE

#4

SI

EV

E

#1

SI

EV

E

#4 S

IE

VE

3" S

IE

VE

SA

M

PL

E

IN

TE

R

VA

L (ft

Sieve analysis results do not include material greater than 3". Refer to the actual boring logs for the possibility of cobble and boulder sized materials.

NT=Not Tested

TA

B

U

LA

TI

O

N O

F

TE

S T

D A

TA

2S A

.G P

J G

E N

G E

O .G

D T

/3

100 1,000 10,000

CONSOLIDATION TEST

Sample inundated at end of test at 3200 psf

S T R A I N

STRESS, psf

LOCATION: 410 West Centennial Boulevard

PROJECT: DPS K9 Facility

CONSOLIDATION TEST

PROJECT NO.: 222722SA

LABORATORY NO.:

DATE: 1/10/23

LIQUID LIMIT: PLASTIC LIMIT: PLASTICITY INDEX:

CLASSIFICATION: ASTM SOIL DESCRIPTION:

BORING NO.: B-2 SAMPLE NO.: RS-1 SAMPLE DEPTH: 1 to 2

G E

O

TE

C H

C O

N S

O

LI

D A

TI

O

N

2S A

.G P

J G

E N

G E

O .G

D T

/3

0 5.0 10.0 15.0 20.0

MOISTURE-DENSITY RELATIONS

PROJECT NO.: 222722SA

LABORATORY NO.:

DATE: 1/10/23

BORING NO.: B-1

LOCATION:

METHOD OF COMPACTION:

LIQUID LIMIT:

CLASSIFICATION:

CLAYEY SAND

410 West Centennial Boulevard

D698A

ASTM SOIL DESCRIPTION:

PLASTIC LIMIT: 16 PLASTICITY INDEX: 14

PROJECT: DPS K9 Facility

SAMPLE DEPTH: 0 to 5SAMPLE NO.: BS-2

SC

D R

Y D

EN

SI

TY

PC

F)

MOISTURE CONTENT (%)

OPTIMUM MOISTURE CONTENT: 10.1%MAXIMUM DRY DENSITY: 119.6 PCF

G E

O

TE

C H

P R

O C

TO

R

2S

A .G

P J

1/

/2

B-1, BS-2 5.0 119.6 10.1 113.4 8.6 94.8 17.3 100 2.3

SWELL TEST DATA

BORING or

TEST PIT No.

SAMPLE

DEPTH, ft

MAXIMUM

DRY DENSITY

(pcf)

OPTIMUM

MOISTURE

CONTENT (%)

REMOLDED

DRY DENSITY

(pcf)

INITIAL

MOISTURE

CONTENT (%)

PERCENT

COMPACTION

TOTAL

SWELL (%)

FINAL

MOISTURE

CONTENT (%)

CONFINING

LOAD

(psf)

1 1

DPS K9 Facility 410 West Centennial Boulevard Casa Grande, Arizona Project No. 222722SASheet of S

W E

LL

T

E S

T

2S A

.G P

J G

E N

G E

O .G

D T

/3