Geotechnical Engineering Report

Transcription

1 Geotechnical Engineering Report Mt. Pisgah Road Slide Paradise, Utah January 15, 2013 Terracon Project No Prepared for: J-U-B Engineers, Inc S 100 W, Suite 180 Logan, UT Prepared by: Terracon Consultants, Inc Pony Express Road, Suite 150 N Bluffdale, Utah 84065

2

3 TABLE OF CONTENTS Page EXECUTIVE SUMMARY... i 1.0 INTRODUCTION PROJECT INFORMATION Project Description Site Location and Description SUBSURFACE CONDITIONS Typical Profile Groundwater RECOMMENDATIONS FOR DESIGN AND CONSTRUCTION Geotechnical Considerations Earthwork Site Preparation Excavation Material Requirements Compaction and Placement Requirements Grading and Drainage Construction Considerations Seismic Considerations Slope Stability Lateral Earth Pressures Soil Nail Wall Design Recommendations Soldier Pile Retaining System Soil Corrosion GENERAL COMMENTS... 9 APPENDICES APPENDIX A FIELD EXPLORATION Exhibit A-1 Project Vicinity Map Exhibit A-2 Boring Location Plan Exhibit A-3 to A-6 Boring Logs Exhibit A-7 Field Exploration Description APPENDIX B SUPPORTING INFORMATION Exhibit B-1 Laboratory Testing Exhibit B-2 Grain Size Distribution Exhibit B-3 UU Triaxial Test Result Exhibit B-4 to B-5 Direct Shear Test Results Exhibit B-6 Rock Unconfined Strength Test Results Exhibits B-7 to B-9 Analytical Results APPENDIX C GLOBAL STABILITY APPENDIX D SUPPORTING DOCUMENTS Exhibit D-1 General Notes Exhibit D-2 Unified Soil Classification System

4 GEOTECHNICAL ENGINEERING REPORT MT. PISGAH ROAD SLIDE PARADISE, UTAH Terracon Project No January 15, 2013 EXECUTIVE SUMMARY A geotechnical exploration has been performed for the Mt. Pisgah Road slope erosion area located near the intersection of Mt. Pisgah Road and Paradise Drive in Paradise, Utah. Two (2) soil borings, designated B-01 and B-02, were performed to depths of approximately 70 feet below the existing ground surface on both sides of the slope erosion area. Based on the information obtained from our subsurface exploration, the site appears to be suitable for the proposed improvements. The following geotechnical considerations were identified: Site Soils: Native soils general consisted of silt underline by layers of silty sand, silty gravel, silt and sandy silt. Sedimentary bedrock was encountered at approximately 47 feet below ground surface. Groundwater was encountered in the borings at approximately 40 while drilling. Slope Stabilization: Scour protection and slope stabilization should be provided to protect the existing slope from erosion caused by stream flows. We understand that a combined soil nail and gabion basket reinforced slope is the preferred stabilization method. In order to meet acceptable long-term global safety requirements, a combination of soil nails and gabion baskets is required. Global Stability: The factor of safety for global stability of the slope with soil nail and gabion basket reinforcement was determined to be This value meets or exceeds UDOT published global stability requirements for walls and slopes located away from adjacent impact. Due to the slope being located away from adjacent structures, seismic loading was not considered. Construction: Close monitoring of the construction operations discussed herein will be critical in achieving proper placement, embedment and backfill for gabion baskets, and soil nail construction. We therefore recommend that Terracon be retained to monitor this portion of the work. This summary should be used in conjunction with the entire report for design purposes. It should be recognized that details were not included or fully developed in this section, and the report must be read in its entirety for a comprehensive understanding of the items contained herein. The section titled GENERAL COMMENTS should be read for an understanding of the report limitations. Responsive Resourceful Reliable i

5 GEOTECHNICAL ENGINEERING REPORT MT. PISGAH ROAD SLIDE PARADISE, UTAH Terracon Project No January 15, INTRODUCTION A geotechnical exploration has been performed for the Mt. Pisgah Road slope erosion area located near the intersection of Mt. Pisgah Road and Paradise Drive in Paradise, Utah. Two (2) soil borings, designated B-01 and B-02, were performed to depths of approximately 70 feet below the existing ground surface on both sides of the erosion area. Logs of the borings along with a project vicinity map and boring location plan are included in Appendix A of this report. The purpose of the exploration was to provide information and geotechnical engineering recommendations relative to: subsurface soil conditions groundwater conditions slope stabilization and erosion control methods global slope stability foundation design and construction seismic considerations 2.0 PROJECT INFORMATION 2.1 Project Description Structures Item Anticipated Slope Stabilization Structure Configuration 1 Description Gabion basket and soil nail reinforced slope. Exposed face height: 31 to 33 feet Embedment: 5 to 6 feet Slope Lengths: 90 to 110 feet (estimated) Grading The stabilized slope will be constructed no steeper than 1:1. 1. Based on cross-section provided by client 2.2 Site Location and Description Location Item Description This project will be located near the intersection of Mt. Pisgah Road (8700 South) and Paradise Drive (approximately 900 West) in Paradise, UT. The site consists of a moderate to steep sloping stream channel located along the south side of Mt. Pisgah Road. The existing slope near the West Paradise Drive intersection has been undermined by the stream below, resulting in sloughing of the channel side slope. Sloughing of the slope is advancing toward Mt. Pisgah Road and poses a long-term threat to stability of the roadway. The slope at this location is estimated to be approximately 35 feet high. Responsive Resourceful Reliable

6 Geotechnical Engineering Report Mt. Pisgah Road Slide Paradise, Utah January 15, 2013 Terracon Project No Item Existing improvements Current ground cover Existing topography Description Existing roadway and stream channel slope. Bare soil and native vegetation consisting of grass and brush. Moderately to steeply sloping toward the stream channel along the south side of Mt. Pisgah Road. 3.0 SUBSURFACE CONDITIONS 3.1 Typical Profile Based on the results of the borings, subsurface conditions on the project site can be generalized as follows: Description Approximate Depth to Bottom of Stratum (feet) 1 Approximate Elevation at Bottom of Stratum (feet) 2 Material Description Consistency/Density Stratum 1 25 to to 4738 Silt Medium Stiff to Stiff Stratum 2 33 to Silty Sand with Gravel to Silty Gravel with Sand Medium Dense to Dense Stratum 3 38 to to 4726 Silt to Sandy Silt Medium Stiff Stratum ½ Stratum 5 70 (termination depth of B-01 and B-02) 4693½ to From existing roadway surface. 2. Based on topographic information provided by the client. Sandy Silt to Silty Sand with Gravel Bedrock: alternating layers of sandstone and mudstone/claystone Loose to Dense Varying degrees of weathering and fracturing Conditions encountered at each boring location are indicated on the individual boring logs. Stratification boundaries on the boring logs represent the approximate location of changes in soil types; in situ, the transition between materials may be gradual. Details for each of the borings can be found on the boring logs in Appendix A. 3.2 Groundwater The borings were monitored while drilling for the presence and level of groundwater. Groundwater was encountered within the depths explored at approximately 40 feet. It should be recognized that fluctuations of the groundwater table may occur due to seasonal variations in the amount of rainfall, runoff, stream flow, upstream and surrounding irrigation practices, future construction and other factors not evident at the time the borings were performed. Evaluation of these factors is beyond the scope of this exploration. Responsive Resourceful Reliable 2

7 Geotechnical Engineering Report Mt. Pisgah Road Slide Paradise, Utah January 15, 2013 Terracon Project No RECOMMENDATIONS FOR DESIGN AND CONSTRUCTION 4.1 Geotechnical Considerations Slope stabilization and erosion protection may consist of a combination gabion baskets and soil nails. Soil nails and gabion baskets should be placed to the lines and grades shown on the project plans and as generally depicted on Exhibit C-1. Gabion baskets at the toe of the slope should be embedded to resist scour. The bottom basket should be placed at a maximum elevation of 4724 feet. The vertical cut portion on the lower portion of the slope should be retained long-term with a soil nail wall or soldier pile wall. Gabion baskets should extend up the face of the slope for slope face stabilization. Access onto the slope for construction will be difficult and may require use of small, light-weight equipment. The contractor should be made aware of site constraints so that proper equipment can be determined. Temporary cut slopes and methods of bracing or maintaining excavation stability is the responsibility of the contractor and is important for long-term stability of this project. The vertical cut portion of the slope should be retained long-term using a soil nail wall or soldier pile wall along with other measures determined by the contractor to provide proper excavation support. The soil nail wall or soldier pile wall should be considered permanent for the purpose of maintaining slope stability. Gabion baskets placed at the bottom of the slope should be embedded for scour protection. Gabion baskets placed on the slope face should be properly benched into the slope face. A filter fabric should be placed behind the gabion baskets to provide protection from fines migration from the native soils into the baskets along the entire length of the wall. Geotechnical engineering recommendations for slope and bank protection and other earth connected phases of the project are outlined below. The recommendations contained in this report are based upon the results of field and laboratory testing (which are presented in Appendices A and B), engineering analyses, and our current understanding of the proposed project. 4.2 Earthwork Site Preparation Prior to placing gabion basket slope protection elements, topsoil and any loose or unstable material should be removed from the slope face. Spot compaction or tamping may be required to densify loose areas on the slope face. Individual rows of gabion baskets should be benched into the slope face. Responsive Resourceful Reliable 3

8 Geotechnical Engineering Report Mt. Pisgah Road Slide Paradise, Utah January 15, 2013 Terracon Project No Excavation Groundwater seepage should be anticipated for excavations approaching the level of bedrock or extending below water level in the adjacent stream channel. Pumping from sumps may be utilized to control water within the excavations. Well points may be required for significant groundwater flow, or where excavations penetrate groundwater to a significant depth Material Requirements All fill materials should be inorganic soils free of vegetation, debris, and fragments larger than four inches in size. Pea gravel or other similar non-cementitious, poorly-graded materials should not be used as fill or backfill without the prior approval of the geotechnical engineer. Fill material should meet the following requirements: Fill Type 1 Embankment Application Slope backfill Requirements Gradation Percent finer Size by weight max 6 inch No. 200 Sieve Plasticity Liquid Limit 35 max Plasticity Index 10 max 1. All fill should consist of approved materials that are free of organic matter and debris. Frozen material should not be used, and fill should not be placed on a frozen subgrade. A sample of each material type should be submitted to the geotechnical engineer for evaluation. Near-surface onsite materials generally consist of silt, underlain by layers of silty sand and silty gravel. It has been our experience that when reusing silt soils, moisture conditioning and compaction to reach required percent compaction can be time consuming and difficult. Also, silty or fine-grained soils that are compacted may become unstable under repetitive construction traffic. Granular soil is recommended Compaction and Placement Requirements Limited fill may be required for minor grading and incidental repair to the roadway and shoulder during or after construction of the wall. Where placed, fill should meet the requirements presented in the following table. Item Maximum Fill Lift Thickness Compaction Requirements 1 12 inches in loose thickness Description 95% of the material s maximum dry density (modified Proctor ASTM D1557) below roadway and slope stabilization elements. Moisture Content Within 2% of the optimum moisture content 1. We recommend that structural fill be tested for moisture content and compaction during placement. Should the results of the in-place density tests indicate the specified moisture or compaction limits have not been met, the area represented by the test should be reworked and retested as required until the specified moisture and compaction requirements are achieved. Responsive Resourceful Reliable 4

9 Geotechnical Engineering Report Mt. Pisgah Road Slide Paradise, Utah January 15, 2013 Terracon Project No Fill placed in areas of the site where existing slopes are steeper than 5:1 (horizontal: vertical) should be benched to reduce the potential for slippage between existing slopes and fills. Benches should be wide enough to accommodate compaction and earth moving equipment, and to allow placement of horizontal lifts of fill Grading and Drainage Final road surface should be graded to prevent water from infiltrating into the gabion baskets zone. A surface drainage ditch should be constructed between the roadway and slope face. Collected water should be directed away from the slope Construction Considerations Soft, pumping, rutting or otherwise unstable subgrade conditions may be encountered during general construction operations, especially if the soils are wetted and/or subjected to repetitive construction traffic. Special consideration will be required during excavation for embedment of the gabion baskets at the toe of the slope. Should pumping, rutting or otherwise unstable conditions be encountered or develop, crushed, angular stone may be required to form a stable surface for construction. A filter fabric such as Mirafi 140N or similar approved product should be placed between the gabion baskets and the native soil to prevent the migration of fine-grained soils into the gabion basket zone. Placement of the fabric should begin at the top of the slope and extend down the full slope face. It is the responsibility of the contractor to provide safe working conditions in connection with underground excavations. Temporary construction excavations should be properly sloped or shored. All excavations should comply with applicable local, state and federal safety regulations, including the current OSHA Excavation and Trench Safety Standards. Earthwork on the project should be observed and evaluated by Terracon. The evaluation of earthwork should include observation and testing of structural fill, site grading, subgrade preparation and proof rolling, foundation bearing soils, and other geotechnical conditions exposed during the construction of the project. 4.3 Seismic Considerations Based on the results of our exploration, the subsurface soil profile is best represented by Site Class D according to the 2009 AASHTO LRFD Seismic Bridge Design Manual. The National Seismic Hazard Map database was searched to identify the peak ground acceleration (PGA) for a 7% probability of exceedence (PE) in 75 years at the project site. Responsive Resourceful Reliable 5

10 Geotechnical Engineering Report Mt. Pisgah Road Slide Paradise, Utah January 15, 2013 Terracon Project No Description Value Site Class 1 D 2 Site Latitude N Site Longitude W S o PGA 0.29g 1 Note: In general accordance with the AASHTO LRFD Seismic Bridge Design Manual, Table Site Class is based on the average characteristics of the upper 100 feet of the subsurface profile. 2 Note: The 2009 AASHTO LRFD Seismic Bridge Design Manual requires a site soil profile determination extending to a depth of 100 feet for seismic site classification. The current scope does not include the required 100 foot soil profile determination. The boring extended to a maximum depth of 70 feet, and this seismic site class definition considers that similar soil conditions continue below the maximum depth of the subsurface exploration. 4.4 Slope Stability The computer program SLIDE 5.0 was used to model global stability of the slope. Soil strength parameters used in our analysis were developed from laboratory testing of collected soil samples and back-calculated values fitting observed slope failure conditions in the field. The existing slope configuration was evaluated for stability and the soil parameters adjusted until modeled failures were representative of observed field conditions and the factor of safety was near 1.0. The adjusted soil parameters were then used to model the improved slope condition. Modeled slope improvements included soil nail stabilization and retainage of the lower near vertical portion of the slope as shown on Exhibit C-1. A soldier pile wall system was not evaluated as part of this scope of work. For modeling purposes, soil nails were spaced in a square grid at 5-foot, angled at 5 degrees from horizontal and were 15 feet long. Final configuration and depth of soil nails for this wall type would be determined by the contractor. Gabion baskets were included on the slope face and in front of the vertical cut slope. Gabion baskets at the toe of the slope and in front of the vertical cut consisted of three columns extending vertically 15 to 18 feet. These baskets were embedded for scour protection. Gabion baskets on the slope face consisted of 2 to 3 basket rows offset horizontally one basket as the rows extended up the slope face. Gabion baskets were placed along the entire face of the slope. Critical failure surfaces were modeled using Spencer s approach for circular and non-circular failure geometry. The cross section of the slope was developed using plans provided by J-U-B Engineers. As per Table 5-2 of the Utah Department of Transportation (UDOT) Geotechnical Design Manual (GDM), Pseudo-static Seismic stability was not included in our analysis because the slope is not adjacent to any other structures. The critical slope stability profiles is included in Appendix C. Soil strength data used in our analysis are presented on the individual slope stability profile. Responsive Resourceful Reliable 6

11 Geotechnical Engineering Report Mt. Pisgah Road Slide Paradise, Utah January 15, 2013 Terracon Project No The minimum required long-term factor of safety (FOS) from the UDOT GDM for a slope not located next to a bridge or other critical structure is 1.2. Based on the cross section provided and soil parameters developed, results of global slope stability analysis indicate a long term FOS of 1.2 or greater. Soil nails should be designed and constructed for a permanent condition and in accordance with FHWA Geotechnical Engineering Circular No. 7. Gabion baskets should be constructed and placed in accordance with manufacturer guidelines and specifications. Rock material placed in gabion baskets should consist of hard, angular to sub-rounded, durable stone that is of such quality that it will not disintegrate on exposure to water or weathering during the life of the structure. Gabion stone should be between 4 inches and 8 inches in nominal diameter. The range in size should allow for a variation of 5 percent oversize and/or 5 percent undersized rock. The size should be such that a minimum of three layers of rock be achieved when filling the gabion baskets. 4.5 Lateral Earth Pressures We understand that the bottom 18 feet of the slope will be excavated vertically and stabilized with soil nails. Due to the steep nature of the slope (approximately 45 degrees), the earth pressure acting on the back of the wall could not be calculated with traditional Coulomb or Rankine earth pressure equations. Therefore, the earth pressure was calculated using the General Limit Equilibrium method in the SLIDE 5.0 slope stability program. In this method, all resistance is removed from in front of the wall and the failure surface is forced through the bottom of the wall. A force is then placed in front of the wall to achieve equilibrium in the system. An equivalent fluid pressure is then back-calculated from the force. Based on the GLE analysis, the equivalent fluid density acting on the back of the wall is 167 pcf and the earth pressure is 167*H psf, with H taken from the top of the vertical cut. 4.6 Soil Nail Wall Design Recommendations We understand that soil nails will be used to support the vertical cut near the bottom of the slope behind the gabion baskets. The contractor is responsible for final design and installation of the soil nails and facing. Care should be taken during installation of soil nails to not destabilize the native soil slopes. Soil nails are typically installed into a nearly vertical cut face. This works well if the soil will stand unsupported for sufficient time to construct the soil nail wall. The borings indicate that the soil encountered in the area of the proposed wall is generally silt, silty sand, and silty gravel. Due to the consistency and density of these soils, the soil nails should be installed as the cut is advanced from the top down. Otherwise, sloughing or failure of the cut may occur. A reinforced, shotcrete facing should be installed immediately following installation of the soil nails. Casing may be required to maintain stability of the nail excavations. Responsive Resourceful Reliable 7

12 Geotechnical Engineering Report Mt. Pisgah Road Slide Paradise, Utah January 15, 2013 Terracon Project No The parameters used in the design of a soil nail wall include the moist unit weight, cohesion, and friction angle. In addition, classification of the soil in contact with the soil nail grout is important for utilization in the Federal Highway Administration (FHWA) design tables regarding ultimate bond strength. The results of the field exploration and laboratory testing were used to develop soil parameters for use in estimating ultimate bond strength for the soil nails. We understand that this information will be used by the contractor to aid in the design of a soil nail wall system. The following table summarizes laboratory test results and estimated soil parameters. Bond strength values should be determined by the wall designer based on the soil parameters encountered at the site and summarized in the following table. We recommend that the ultimate bond strength not exceed 22psi (150KPa) for rotary drilled borings. Soil Properties for Soil Nail Design Elevation (ft) Soil Type Effective Unit Weight Of Soil, γ (pcf) Friction Angle, φ (degrees) Cohesion, C (psf) 4740 to 4730 Silty Sand to 4720 Silt Soil nails should be a minimum of 15 feet long to meet global stability requirements. The soil nail retaining system should be designed to resist a minimum lateral equivalent fluid pressure of 167pcf. Quality control should be completed in accordance with UDOT and FHWA requirements. We recommend that soil nail quality control testing include at least one verification test prior to installation of production nails and a sufficient number of production proof tests to meet 5% of the total number of nails installed. Creep tests should be performed with each of the verification and proof tests. The verification test should be performed on a sacrificial soil nail incrementally loaded while measuring creep at specified loads. Verification tests should include loading the soil nail to the ultimate design load. The proof tests should consist of loading the nails to at least 130% of the design load. 4.7 Soldier Pile Retaining System As an alternative to soil nails, the slope may be retained using soldier piles and lagging. The contractor is responsible for the proper design and installation of a soldier pile and lagging retaining system. The following L-pile soil parameters may be used to aid in design of the wall system. The wall design should be reviewed by the project engineer prior to installation. Responsive Resourceful Reliable 8

13 Geotechnical Engineering Report Mt. Pisgah Road Slide Paradise, Utah January 15, 2013 Terracon Project No L-Pile Soil Parameters Soil Type Unit Weight (pcf) Cohesion (psf) Friction Angle (degrees) Soil Modulus K (pci) E 50 Silt 115 1, Silty Sand Gravel Rock 135 4, Based on RMI of 45, Fair Rock. The soldier pile retaining system should be designed to resist a minimum lateral equivalent fluid pressure of 167pcf. A row of anchors may be required to retain the slope and prevent the soldier piles from rotating. 4.8 Soil Corrosion The results of analytical tests performed on samples from the site are presented in the following table. Sample ph Laboratory Resistivity (ohm-cm) 35 ft , ft ft Resistivity values less than 2,000 ohm-cm indicate corrosive conditions for buried metal. These test results are provided to assist in determining the type and degree of corrosion protection that may be required. We recommend that a certified corrosion engineer determine the need for corrosion protection and design appropriate protective measures. Complete test results are included in Appendix B. 5.0 GENERAL COMMENTS Terracon should be retained to review the final design plans and specifications so comments can be made regarding interpretation and implementation of our geotechnical recommendations in the design and specifications. Terracon also should be retained to provide observation and testing services during grading, excavation, foundation construction and other earth-related construction phases of the project. Responsive Resourceful Reliable 9

14 Geotechnical Engineering Report Mt. Pisgah Road Slide Paradise, Utah January 15, 2013 Terracon Project No The analysis and recommendations presented in this report are based upon the data obtained from the borings performed at the indicated locations and from other information discussed in this report. This report does not reflect variations that may occur between borings, across the site, or due to the modifying effects of construction or weather. The nature and extent of such variations may not become evident until during or after construction. If variations appear, we should be immediately notified so that further evaluation and supplemental recommendations can be provided. The scope of services for this project does not include either specifically or by implication any environmental or biological (e.g., mold, fungi, bacteria) assessment of the site or identification or prevention of pollutants, hazardous materials or conditions. If the owner is concerned about the potential for such contamination or pollution, other studies should be undertaken. This report has been prepared for the exclusive use of our client for specific application to the project discussed and has been prepared in accordance with generally accepted geotechnical engineering practices. No warranties, either expressed or implied, are intended or made. Site safety, excavation support, and dewatering requirements are the responsibility of others. In the event that changes in the nature, design, or location of the project as outlined in this report are planned, the conclusions and recommendations contained in this report shall not be considered valid unless Terracon reviews the changes and either verifies or modifies the conclusions of this report in writing. Responsive Resourceful Reliable 10

15 APPENDIX A FIELD EXPLORATION

16 SUBJECT SITE DIAGRAM IS FOR GENERAL LOCATION ONLY, AND IS NOT INTENDED FOR CONSTRUCTION PURPOSES. REFERENCE: MICROSOFT VIRTUAL EARTH Project Mngr: Drawn By: Checked By: Approved By: JWG CRC JWG RLC Project No Task No. 01 Scale: Not to Scale Date: 8/08/ S. Pony Express Road, Suite 150N Bluffdale, Utah PROJECT VICINITY MAP Mt. Pisgah Road Slide Paradise, Utah J-U-B Engineers FIGURE A-1

17 B-01 B-02 LEGEND: Approximate Boring Location DIAGRAM IS FOR GENERAL LOCATION ONLY, AND IS NOT INTENDED FOR CONSTRUCTION PURPOSES. REFERENCE: MICROSOFT VIRTUAL EARTH Project Mngr: Drawn By: Checked By: Approved By: JWG CRC JWG RLC Project No Task No. 01 Scale: Not to Scale Date: 8/05/ S. Pony Express Road, Suite 150 N Bluffdale, Utah BORING LOCATION PLAN Mt. Pisgah Road Slide Paradise, Utah J-U-B Engineers FIGURE A-2

18 LOG OF BORING NO. B-01 CLIENT J-U-B Engineers SITE Mt. Pisgah Road and Paradise Drive PROJECT Paradise, UT Mt. Pisgah Road Slide Boring Location: Western side of slide SAMPLES TESTS Page 1 of 2 BOREHOLE_ GPJ TERRACON.GDT 11/16/12 GRAPHIC LOG 30 DESCRIPTION SILT: soft to stiff, light brown to grayish brown SILTY SAND: with gravel, medium dense, gray SS Sieve SANDY SILT: 37 medium stiff to stiff, gray Continued Next Page SS SS SS SS SS SS OTHER The stratification lines represent the approximate boundary lines Sieve = grain size distribution, DS = Direct Shear Test, UC = Unconfined Compression Test between soil and rock types: in-situ, the transition may be gradual. WATER LEVEL OBSERVATIONS, ft WL WL WL Elevation: 4766 ft 40 WD DEPTH, ft USCS Soil Symbol NUMBER TYPE RECOVERY, in. BORING STARTED BORING COMPLETED RIG PENETRATION RESISTANCE BLOWS / ft. WATER CONTENT, % DRY UNIT WEIGHT, PCF LIQUID LIMIT Simco CRC PLASTICITY INDEX FOREMAN JOB # % PASSING NO. 200 SIEVE CRC

19 CLIENT SITE J-U-B Engineers Mt. Pisgah Road and Paradise Drive Paradise, UT LOG OF BORING NO. B-01 PROJECT Mt. Pisgah Road Slide SAMPLES TESTS Page 2 of 2 GRAPHIC LOG SILTY SAND: with gravel, dense, gray BEDROCK: Alternating layers of sandstone and softer mudstone/claystone, decreased weathering with depth DEPTH, ft USCS Soil Symbol NUMBER ML 8 SS TYPE SS 10 SS RECOVERY, in RC RC RC 60 PENETRATION RESISTANCE 31 50/ BLOWS / ft. WATER CONTENT, % DRY UNIT WEIGHT, PCF LIQUID LIMIT PLASTICITY INDEX % PASSING NO. 200 SIEVE 66 OTHER DS, Sieve UC BOTTOM OF BORING AT APPROXIMATELY 70 FEET BOREHOLE_ GPJ TERRACON.GDT 11/16/12 The stratification lines represent the approximate boundary lines Sieve = grain size distribution, DS = Direct Shear Test, UC = Unconfined Compression Test between soil and rock types: in-situ, the transition may be gradual. WATER LEVEL OBSERVATIONS, ft BORING STARTED WL 40 WD BORING COMPLETED WL RIG Simco FOREMAN CRC WL CRC JOB #

20 LOG OF BORING NO. B-02 CLIENT J-U-B Engineers SITE Mt. Pisgah Road and Paradise Drive PROJECT Paradise, UT Mt. Pisgah Road Slide Boring Location: Eastern side of slide SAMPLES TESTS Page 1 of 2 BOREHOLE_ GPJ TERRACON.GDT 11/16/12 GRAPHIC LOG SILT: medium stiff to stiff, light brown SILTY SAND: gray, trace gravel SILTY GRAVEL: with sand, dense, gray DESCRIPTION SILT: medum stiff, brown to greenish gray SILTY SAND: with gravel, dense, gray Continued Next Page SS ST SS SS ST SS SS OTHER UU Triaxial DS, Sieve The stratification lines represent the approximate boundary lines Sieve = grain size distribution, DS = Direct Shear Test, UC = Unconfined Compression Test between soil and rock types: in-situ, the transition may be gradual. WATER LEVEL OBSERVATIONS, ft WL WL WL Elevation: ft 40 WD DEPTH, ft USCS Soil Symbol NUMBER TYPE RECOVERY, in. BORING STARTED BORING COMPLETED RIG PENETRATION RESISTANCE BLOWS / ft. WATER CONTENT, % DRY UNIT WEIGHT, PCF LIQUID LIMIT Simco CRC PLASTICITY INDEX FOREMAN JOB # % PASSING NO. 200 SIEVE Sieve CRC

21 CLIENT SITE J-U-B Engineers Mt. Pisgah Road and Paradise Drive Paradise, UT LOG OF BORING NO. B-02 PROJECT Mt. Pisgah Road Slide SAMPLES TESTS Page 2 of 2 GRAPHIC LOG SILTY SAND: with gravel, dense, gray BEDROCK: Alternating layers of mudstone/claystone and sandstone with layers of poorly cemented gravel, greenish gray, heighly weathered and fractured DEPTH, ft USCS Soil Symbol NUMBER 8 9 TYPE SS SS RECOVERY, in RC RC RC RC 24 PENETRATION RESISTANCE BLOWS / ft. WATER CONTENT, % 21 DRY UNIT WEIGHT, PCF LIQUID LIMIT PLASTICITY INDEX % PASSING NO. 200 SIEVE 18 OTHER Sieve UC BOTTOM OF BORING AT APPROXIMATEY 70 FEET BOREHOLE_ GPJ TERRACON.GDT 11/16/12 The stratification lines represent the approximate boundary lines Sieve = grain size distribution, DS = Direct Shear Test, UC = Unconfined Compression Test between soil and rock types: in-situ, the transition may be gradual. WATER LEVEL OBSERVATIONS, ft BORING STARTED WL 40 WD BORING COMPLETED WL RIG Simco FOREMAN CRC WL CRC JOB #

22 Field Exploration Description The boring locations were laid out at the site by our field engineer based on existing site features. Right angles for the boring locations were estimated. The locations of the borings should be considered accurate only to the degree implied by the means and methods used to define them. The borings were drilled with a truck-mounted rotary drill rig using continuous flight hollow-stem augers to advance the boreholes. Samples of the soil encountered in the borings were obtained using the split-barrel and thin-walled shelby tube sampling procedures. In the split-barrel sampling procedure, the number of blows required to advance a standard 2- inch O.D. split-barrel sampler the last 12 inches of the typical total 18-inch penetration by means of a 140-pound hammer with a free fall of 30 inches, is the standard penetration resistance value (SPT-N). This value is used to estimate the in-situ relative density of cohesionless soils and consistency of cohesive soils. An automatic SPT hammer was used to advance the split-barrel sampler in the borings performed on this site. A significantly greater efficiency is achieved with the automatic hammer compared to the conventional safety hammer operated with a cathead and rope. This higher efficiency has an appreciable effect on the SPT-N value. The effect of the automatic hammer's efficiency has been considered in the interpretation and analysis of the subsurface information for this report. The samples were tagged for identification, sealed to reduce moisture loss, and taken to our laboratory for further examination, testing, and classification. Information provided on the boring logs attached to this report includes soil descriptions, consistency evaluations, boring depths, sampling intervals, and groundwater conditions. The borings were backfilled with auger cuttings prior to the drill crew leaving the site. A field log of each boring was prepared by the drill crew. These logs included visual classifications of the materials encountered during drilling as well as the field engineer s interpretation of the subsurface conditions between samples. Final boring logs included with this report represent the engineer's interpretation of the field logs and include modifications based on laboratory observation and tests of the samples. Exhibit A-7

23 APPENDIX B LABORATORY TESTING

24 Laboratory Testing Descriptive classifications of the soils indicated on the boring logs are in accordance with the enclosed General Notes and the Unified Soil Classification System. Also shown are estimated Unified Soil Classification Symbols. A brief description of this classification system is attached to this report. All classification was by visual manual procedures. Selected samples were further classified using the results of Atterberg limit and sieve analysis testing. The Atterberg limit and sieve analysis test results are also provided on the boring logs. Representative soil samples were selected for testing to determine physical and engineering properties and to aid in classification. Following are the laboratory tests performed and a brief description of each test: Natural Water Content: The percentage of water in the soil at the sample location. Percent Passing the No. 200 Sieve: Amount of combined clay and silt-sized particles in the soil sample. Atterberg Limits: Consistency and range of moisture content within which the material is workable. Sieve Analysis: Measurement of the grain-size distribution of a soil sample as a percentage of total dry sample weight. UU Triaxial Compression: Shear strength under loading conditions. Direct Shear: Shear strength under loading conditions. Unconfined Compression: Compressive strength. Results of the laboratory tests are summarized on the boring logs in Appendix A, reported in Appendix B, and in this report. Exhibit B-1

25 100 U.S. SIEVE OPENING IN INCHES / /4 3/ U.S. SIEVE NUMBERS HYDROMETER PERCENT FINER BY WEIGHT COBBLES GRAIN SIZE IN MILLIMETERS GRAVEL SAND coarse fine coarse medium fine SILT OR CLAY TC_GRAIN_SIZE GPJ TERRACON.GDT 11/15/12 Specimen Identification B-01 B-01 B-02 B-02 B-02 Specimen Identification B-01 B-01 B-02 B-02 B ft 40.0ft 25.0ft 30.0ft 45.0ft 35.0ft 40.0ft 25.0ft 30.0ft 45.0ft D D Classification SANDY SILT(ML) D D10 LL PL %Gravel %Sand %Silt %Clay GRAIN SIZE DISTRIBUTION Project: Mt. Pisgah Road Slide Site: Mt. Pisgah Road and Paradise Drive Paradise, UT Job #: Date: PI Cc Cu

26 Unconsolidated-Undrained Triaxial Compression Test (ASTM D2850) Deviator Stress, psf Axial Deviator Shear Strain Stress Stress (%) (psf) (psf) Strain, % Sample Diameter (in): 2.76 Moist Unit Weight (pcf): 120 Sample Height (in): 6.47 Moisture Content (%): -- Sample Volume (cf): Dry Unit Weight (pcf): -- Confining Stress (psf): Strain at Falure (%) 17 Strain Rate (%/min): 1.00 Shear Stress at Falure (psf) 1995 Strain Rate (in/min): Project Name: Mt. Pisgah Road Slide Project No.: Location: Mt. Pisgah Road and Paradise Drive Sample: 10' Sample Description: SILT Exhibit B-3

27 Maximum Shear Stress (psf) SOIL DIRECT SHEAR RESULTS Las Vegas, Nevada (64) Laboratory ,000 Shear Strength 2,000 1, ,000 2,000 3,000 4,000 5,000 Normal Stress (psf) Test # Sample Information Sample Lab ID Depth (ft) Diameter (in) Test Parameters Test Stresses Initial Conditions Normal (psf) Max Shear (psf) Height (in) Moisture (%) Density (pcf) Final Conditions Height (in) Moisture (%) A B , B B , , C B , , Notes and Special Test Conditions Project Name Location Client Project Information Mt. Pisgah Road Slide Mt. Pisgah Road, Paradise, Utah J-U-B Engineers, Inc. Test Results Friction Angle ( ) Cohesion (psf) Shear Rate (in/min)

28 Maximum Shear Stress (psf) SOIL DIRECT SHEAR RESULTS Las Vegas, Nevada (64) Laboratory ,000 Shear Strength 2,000 1, ,000 2,000 3,000 4,000 5,000 Normal Stress (psf) Test # Sample Information Sample Lab ID Depth (ft) Diameter (in) Test Parameters Test Stresses Initial Conditions Normal (psf) Max Shear (psf) Height (in) Moisture (%) Density (pcf) Final Conditions Height (in) Moisture (%) A B B B , , C B , , Notes and Special Test Conditions Project Name Location Client Project Information Mt. Pisgah Road Slide Mt. Pisgah Road, Paradise, Utah J-U-B Engineers, Inc. Test Results Friction Angle ( ) Cohesion (psf) Shear Rate (in/min)

29 Stress, psf Strain, % Specimen Identification 1 at ft 2 at ft Classification Sandstone Sandstone Moisture Content, % Dry Density, pcf x UNCONFINED COMPRESSION TEST RESULTS Project Name: Mt. Pisgah Road Slide Location: Paradise, Utah Project No.: Date: /15/2012 Exhibit B-6

30

31

32

33 APPENDIX C GLOBAL STABILITY

34 DIAGRAM IS FOR GENERAL LOCATION ONLY, AND IS NOT INTENDED FOR CONSTRUCTION PURPOSES. Project Mngr: Drawn By: Checked By: Approved By: RLC ABD RLC RLC Project No. Task No. Scale: Date: As Shown 11/15/ S Pony Express Rd, Ste 150N Bluffdale, Utah ACTIVE EARTH PRESSURE STABILITY ANALYSIS Mt. Pisgah Road Slide Paradise, Utah J-U-B Engineers EXHIBIT C-1

35 APPENDIX D SUPPORTING DOCUMENTS

36 GENERAL NOTES DRILLING & SAMPLING SYMBOLS: SS: Split Spoon /8" I.D., 2" O.D., unless otherwise noted HS: Hollow Stem Auger ST: Thin-Walled Tube - 2" O.D., unless otherwise noted PA: Power Auger RS: Ring Sampler " I.D., 3" O.D., unless otherwise noted HA: Hand Auger DB: Diamond Bit Coring - 4", N, B RB: Rock Bit BS: Bulk Sample or Auger Sample WB: Wash Boring or Mud Rotary The number of blows required to advance a standard 2-inch O.D. split-spoon sampler (SS) the last 12 inches of the total 18-inch penetration with a 140-pound hammer falling 30 inches is considered the Standard Penetration or N-value. WATER LEVEL MEASUREMENT SYMBOLS: WL: Water Level WS: While Sampling N/E: Not Encountered WCI: Wet Cave in WD: While Drilling DCI: Dry Cave in BCR: Before Casing Removal AB: After Boring ACR: After Casing Removal Water levels indicated on the boring logs are the levels measured in the borings at the times indicated. Groundwater levels at other times and other locations across the site could vary. In pervious soils, the indicated levels may reflect the location of groundwater. In low permeability soils, the accurate determination of groundwater levels may not be possible with only short-term observations. DESCRIPTIVE SOIL CLASSIFICATION: Soil classification is based on the Unified Classification System. Coarse Grained Soils have more than 50% of their dry weight retained on a #200 sieve; their principal descriptors are: boulders, cobbles, gravel or sand. Fine Grained Soils have less than 50% of their dry weight retained on a #200 sieve; they are principally described as clays if they are plastic, and silts if they are slightly plastic or non-plastic. Major constituents may be added as modifiers and minor constituents may be added according to the relative proportions based on grain size. In addition to gradation, coarse-grained soils are defined on the basis of their in-place relative density and fine-grained soils on the basis of their consistency. CONSISTENCY OF FINE-GRAINED SOILS RELATIVE DENSITY OF COARSE-GRAINED SOILS Unconfined Compressive Strength, Qu, psf Standard Penetration or N-value (SS) Blows/Ft. Consistency Standard Penetration or N-value (SS) Blows/Ft. Relative Density < Very Soft 0 3 Very Loose 500 1, Soft 4 9 Loose 1,000 2, Medium Stiff Medium Dense 2,000 4, Stiff Dense 4,000 8, Very Stiff > 50 Very Dense 8,000+ > 30 Hard RELATIVE PROPORTIONS OF SAND AND GRAVEL Descriptive Term(s) of other constituents Percent of Dry Weight Major Component of Sample GRAIN SIZE TERMINOLOGY Particle Size Trace < 15 Boulders Over 12 in. (300mm) With Cobbles 12 in. to 3 in. (300mm to 75 mm) Modifier > 30 Gravel 3 in. to #4 sieve (75mm to 4.75 mm) RELATIVE PROPORTIONS OF FINES Descriptive Term(s) of other constituents Trace With Modifiers Percent of Dry Weight < > 12 Sand Silt or Clay #4 to #200 sieve (4.75mm to 0.075mm) Passing #200 Sieve (0.075mm) PLASTICITY DESCRIPTION Term Non-plastic Low Medium High Plasticity Index > 30

37 Coarse Grained Soils More than 50% retained on No. 200 sieve Fine-Grained Soils 50% or more passes the No. 200 sieve UNIFIED SOIL CLASSIFICATION SYSTEM Criteria for Assigning Group Symbols and Group Names Using Laboratory Tests A Gravels More than 50% of coarse fraction retained on No. 4 sieve Sands 50% or more of coarse fraction passes No. 4 sieve Silts and Clays Liquid limit less than 50 Silts and Clays Liquid limit 50 or more Clean Gravels Less than 5% fines C Gravels with Fines More than 12% fines C Clean Sands Less than 5% fines D Sands with Fines More than 12% fines D Group Symbol Soil Classification Group Name B Cu 4 and 1 Cc 3 E GW Well-graded gravel F Cu 4 and/or 1 Cc 3 E GP Poorly graded gravel F Fines classify as ML or MH GM Silty gravel F,G, H Fines classify as CL or CH GC Clayey gravel F,G,H Cu 6 and 1 Cc 3 E SW Well-graded sand I Cu 6 and/or 1 Cc 3 E SP Poorly graded sand I Fines classify as ML or MH SM Silty sand G,H,I Fines Classify as CL or CH SC Clayey sand G,H,I inorganic PI 7 and plots on or above A line J CL Lean clay K,L,M organic PI 4 or plots below A line J ML Silt K,L,M Liquid limit - oven dried Liquid limit - not dried 0.75 OL Organic clay K,L,M,N Organic silt K,L,M,O inorganic PI plots on or above A line CH Fat clay K,L,M organic PI plots below A line MH Elastic Silt K,L,M Liquid limit - oven dried Liquid limit - not dried 0.75 OH Highly organic soils Primarily organic matter, dark in color, and organic odor PT Peat Organic clay K,L,M,P Organic silt K,L,M,Q A Based on the material passing the 3-in. (75-mm) sieve B If field sample contained cobbles or boulders, or both, add with cobbles or boulders, or both to group name. C Gravels with 5 to 12% fines require dual symbols: GW-GM well-graded gravel with silt, GW-GC well-graded gravel with clay, GP-GM poorly graded gravel with silt, GP-GC poorly graded gravel with clay. D Sands with 5 to 12% fines require dual symbols: SW-SM well-graded sand with silt, SW-SC well-graded sand with clay, SP-SM poorly graded sand with silt, SP-SC poorly graded sand with clay E (D30) Cu = D 60/D 10 Cc = D10 x D 2 60 F If soil contains 15% sand, add with sand to group name. G If fines classify as CL-ML, use dual symbol GC-GM, or SC-SM. H If fines are organic, add with organic fines to group name. I If soil contains 15% gravel, add with gravel to group name. J If Atterberg limits plot in shaded area, soil is a CL-ML, silty clay. K If soil contains 15 to 29% plus No. 200, add with sand or with gravel, whichever is predominant. L If soil contains 30% plus No. 200 predominantly sand, add sandy to group name. M If soil contains 30% plus No. 200, predominantly gravel, add gravelly to group name. N PI 4 and plots on or above A line. O PI 4 or plots below A line. P PI plots on or above A line. Q PI plots below A line.