C02_Attachment_4_-_Geotechnical_Support_SOW_1.docx

STATEMENT OF WORK

San Joaquin River Restoration SJRRP Geotechnical Investigation Support

1.0 General Description

This is a non-personal services contract to provide geotechnical support services. The Government shall not exercise any supervision or control over the contract service providers (i.e., subcontractors) performing the services. Such contract service providers shall be accountable solely to the Contractor who, in turn, is responsible to the Government.

2.0 Background

Geotechnical investigations are required by the San Joaquin River Restoration Program (SJRRP) to support the design of the Mendota Pool Bypass and Reach 2B Improvements Project. Potential locations for geotechnical investigation will be provided upon award of the contract and should be drilled as further described in Section 7 below.

3.0 Period of Performance

September 15, 2022 to August 1, 2023

4.0 Government Furnished Property, Equipment, and Services

No government furnished equipment will be provided. A Reclamation owned Conex Box, located at Reclamation’s Check 21 Structure property is available for core box and excess sample storage. Reclamation will be responsible for developing laboratory testing plans and prescribing subsequent drilling needs as described in Section 7-Tasks 1 through 5. Reclamation personnel retain the right to observe the Contractor’s activities in the field without notice. Reclamation will be responsible for all landowner coordination for survey and investigation activities.

5.0 Contractor Furnished Items and Services

The Contractor shall provide all equipment, supplies, management, supervision, personnel, and transportation, except as specified herein as government-furnished, necessary to assure that all services are in accordance with the contract and all applicable laws and regulations. The Contractor shall ensure all work meets performance standards specified in this Statement of Work and referenced documents. The Contractor shall provide at least one Qualified Field Representative (QFR) at each drill rig/cone penetration test (CPT) rig/excavator, who shall be present full time during any work at their respective drill hole location/sounding/test pit. The Contractor shall provide multiple QFRs (i.e., one per drill hole/sounding/test pit) if work is performed concurrently at multiple locations. See Section 11 for qualification requirements. For drill holes and soundings located within orchards, the Contractor shall utilize equipment that will fit within orchard rows and minimize damage to trees (e.g., CME 45 trailer or track mounted drill rig).

6.0 Site Access

Reclamation owns or holds temporary entry rights to the lands and/or parcels to be investigated under this contract.

7.0 Specific Tasks

The Contractor shall implement the following geotechnical investigation, support tasks, and requirements stated herein at Reclamation’s discretion, as described below. All referenced standards shall be performed in accordance with the most recent version available at the time of performance. The Contractor shall maintain the provided naming convention for each drill hole/sounding/test pit that includes the type of exploration, last two digits of the year of exploration, and the number of the drill hole/sounding/test pit according to the provided locations and naming convention following award. All work shall be completed in accordance with Reclamation’s Safety and Health Standards and applicable Occupational Safety and Health Administration (OSHA) Standards.

Task 1 – Geotechnical Investigation

1. Standard Penetration Test (SPT) Drill Holes

a. General

This task includes drilling standard penetration test (150 SPT) drill holes in accordance with the procedures defined herein. The price schedule includes a performance incentive for 60 SPTs. The Contractor shall be responsible for utility location and clearance for all drilling activities. The Contractor shall provide a health and safety plan (HASP) and schedule of drilling as approved by Reclamation (see Section 11.0).

Oversight shall be performed by a QFR whom shall be onsite to monitor all work and shall be responsible for collecting data during drilling and sampling, visual soil classification and description, sample preservation, and backfill or well completion of the drill holes. The Contractor shall provide one QFR at each drill rig, who shall be present full time during the work at each drill hole location. The Contractor shall provide multiple QFRs (i.e., one per drill hole) if work is performed concurrently at multiple drill holes.

The Contractor shall provide adequate equipment to allow for the below tasks. For drill holes located within orchards, the Contractor shall utilize equipment that will fit within orchard rows and minimize damage to trees (e.g., CME 45 trailer or track mounted drill rig). The Contractor may determine that a location provided by the COR is not accessible due to existing structures or potential for crop damage. If this occurs, the Contractor may submit a request for moving the drill hole to the nearest accessible location. Before any holes are relocated, the Contractor shall provide the Contracting Office Representative (COR) with a written description of the need for relocations and applicable photographs of obstacle(s), proposed location(s) for the drill hole(s), and a map with the original and proposed location(s). The Contractor shall proceed with drilling the relocated hole only after receiving approval of the COR. All drilling must occur within the pre-approved work areas. The Contractor shall complete the drill holes as observation wells or backfill according to the procedures as directed by Reclamation.

b. Drilling Equipment and Methods

i. Equipment

The Contractor shall provide the equipment necessary to allow for the below sampling methods, in relevant drill holes, to provide adequate soil samples for the specified laboratory testing of samples from drill holes. Drill holes located within orchards, the Contractor shall utilize equipment that will fit within orchard rows and minimize damage to trees (e.g., CME 45 trailer or track mounted drill rig). Additionally, many locations will be within wetland or riparian corridors and require access in muddy, wet, or inundated areas which may require the use of track mounted equipment and site improvement.

The Contractor is responsible for providing all labor, materials and equipment that can access drill hole locations with minimal impact to the subgrade (e.g., rutting, potholes, etc.), existing trees or crop rows. Some drill hole locations may only be accessible during the fall/winter due to the potential impacts drilling activities can have on existing crops which will be discussed and scheduled appropriately in biweekly coordination meetings with Reclamation.

The Contractor shall use a hydraulically operated automatic hammer to perform all SPT sampling and shall provide documentation of hammer energy transfer efficiency, per ASTM D4633. The Contractor shall perform SPT sampling according to ASTM D1586 with a standard 1.375-inch internal diameter, 24-inch sample length split-barrel sampler. A constant internal diameter split-barrel sampler (i.e., no recess for liners) is preferred, but any deviations must be documented. A hollow stem flight auger system equipped with a split barrel flight auger dry core sampler (FADC) will be used for continuous sampling of SPT drill holes. Outside diameter of augers used for exploratory drill holes shall not be greater than 12 inches.

ii. Methods

The Contractor shall drill and sample the drill holes using a combination of SPT and hollow stem flight auger methods, including flight auger dry core (FADC) according to ASTM D6151. In the presence of an unstable drill hole in which heaving sands are encountered (i.e., flowing sands that move upward into the hollow stem augers), drilling methods must change to mud rotary (MR) methods according to ASTM D5783. Note that FADC will not be feasible when drilling with MR methods. The drilling mud shall be biodegradable.

Drilling and sampling are to be performed at the locations provided by the COR. The Contractor shall maintain the provided naming convention for each drill hole that includes the type of exploration (SPT), last two digits of the year of exploration, and the number of the drill hole according to the naming convention provided by the COR.

Continuous sampling shall occur throughout the full depth of SPT drill holes.

SPTs shall be performed in accordance with ASTM D1586. The Contractor shall advance the drill holes to the maximum target depths of 75 ft, or as otherwise provided for each hole by the COR, or terminate the drill hole at practical refusal depth if less than full target depth. The Contractor shall terminate a SPT upon refusal, based on a criterion of 10 blows with no advancement; or 50 blows per 0.5-foot of advancement when performed at depths of 0 to 40 feet; 80 blows per 0.5-foot of advancement when performed at depths of 40 to 80 feet. Blow rates of the hammer shall not exceed 55 blows per minute and should remain consistent with the blow rates in which the hammer efficiency was measured.

Previously completed drill holes in the project area encountered flowing sands during drilling, a problematic condition that can prevent obtaining an accurate SPT and sample. Flowing sand conditions are expected during the performance of this scope of work, and when encountered during drilling the Contractor shall switch methods to perform mud rotary drilling to collect all SPT samples at the direction of the Contractor’s QFR. Mud rotary drilling and sampling shall be in accordance with ASTM D5783 throughout the full depth of selected drill holes to 75 feet, or as provided by the COR. The collection and proper disposal of drilling mud is the sole responsibility of the contractor.

c. Sampling

i. SPT

The Contractor shall perform SPTs at 2.5-foot intervals (i.e., vertical spacing) throughout the full depth of each drill hole. While conducting an SPT, the Contractor’s QFR shall record blows per 0.1-feet (tenth) of advancement or penetration per blow. Prior to testing, the Contractor’s QFR must confirm that the drill hole is stable with a maximum of 4 inches of slough (disturbed material inside the augers) and that a flowing sand condition is not present.

The Contractor’s QFR shall maintain the provided naming convention for each drill hole that includes the type of exploration (SPT), last two digits of the year of exploration, and the number of the drill hole as provided by the COR.

After the SPT sampler is retrieved, the Contractor’s QFR shall remove one side of the split barrel and photograph (see Section E) the soil while still within the remaining side of the split barrel sampling equipment, record the depth of each material change, geologically log each soil type present per Section D below, and collect samples for laboratory testing.

The Contractor’s QFR shall collect each soil type collected in SPT sampler for potential laboratory testing. If there is more than one soil type contained in the SPT sampler, the different soil types should be collected separately and not combined. If there is not enough material of a soil type for laboratory testing, the sample bag must be supplemented with soil of the same type and same depth interval from the FADC that is over-cored that SPT interval. Samples shall be preserved and sealed within a water-tight container or double bagged such that natural water content is not lost during sample storage. The Contractor’s QFR shall label, preserve, and transport all samples for potential geotechnical laboratory testing according to ASTM D4220 Group B. The Contractor shall not allow any samples to freeze or be subjected to excessive heat.

The Contractor’s QFR shall collect corrosion testing samples at select drill hole locations as directed by the COR or government representative. The samples should be stored in a cooler and transported to laboratory for analytical testing. The Contractor’s QFR will develop two duplicate Inventory Sheets for samples collected, using the approved laboratory chain of custody form. One copy will be kept with field notes and the second copy will be included with the samples when delivered to the testing laboratory. To avoid sample contamination, collect sample using clean sealable bags, clean hands or latex gloves, and a rust-free tool (ideally stainless steel). The sample size shall equal one quart-sized bag per selected drill hole (min. 1 lb. each). Remove as much air as possible and seal tightly. Label each bag with project information, sample number, drill hole, depth, date and time, and field pH (when available). Put samples on ice in cooler, seal the cooler with strapping tape, and deliver to an approved laboratory for testing. If applicable, chloride testing requires no preservatives, but testing should be performed within 28 days of sample collection. Sulfate testing recommends that the sample be kept cool at ~40°F and that testing be performed within 28 days of sample collection. Samples to be tested for soil corrosivity (pH, soluble sulfate and chloride concentrations) following EPA testing standards. Electrical conductivity (EC) following EPA testing standard. The type and frequency may be revised by the COR based on conditions encountered in the field.

ii. Flight Auger Dry Core (FADC)

Soil collected in the FADC sampler that is not represented in the prior SPT should be collected for potential laboratory testing such that all changes in soil type within a drill hole are captured. FADC soil should supplement the SPT samples if additional volume of soil is needed for accurate laboratory classification (e.g., soils containing gravel-size particles). Such samples shall be preserved and sealed within a water-tight container or double bagged such that natural water content is not lost during sample storage. The Contractor’s QFR shall label, preserve, and transport all samples for potential geotechnical laboratory testing according to ASTM D4220 Group B. The Contractor shall not allow any samples to freeze or be subjected to excessive heat.

The remainder of the FADC soil should be placed in waxed fiber or plastic core boxes in continuous order of depth. Annotated photographs (i.e., containing project, drill hole, depth etc.) are required of the core samples within the sampler before removal and again in the labeled core box. The Contractor’s QFR shall label each sample liner or core box with the following information prior to removing from the drilling site: project name, date drilled, drill hole name/number, box number/total number of boxes for that drill hole, total depth of drill hole, marking within each box that specify top and bottom depths for core samples per run. FADC shall be photographed according to Section E.

The Contractor shall maintain and store all boxed FADC core and excess samples not immediately being sent for lab testing purposes collected under this scope of work in a Conex box located at Reclamation owned Check 21 Structure property. The Contractor is responsible for furnishing Conex boxes for storage at the Check 21 Structure property. Excess sample bags shall be labeled, categorized, and organized in the event it needs to be utilized for future analysis by Reclamation.

d. Geologic Logging

The Contractor’s QFR shall maintain the provided naming convention for each drill hole that includes the type of exploration (SPT), last two digits of the year of exploration, and the number of the drill hole according to the naming convention provided by the COR.

The Contractor’s QFR shall collect all required exploration data to develop drill hole logs. The Contractor’s QFR shall document the depth to groundwater using an electronic water level sounding device and note date, time and depth of auger when reading is taken, whether measured during or after drilling, and any other information that may affect the groundwater level measurements. Groundwater measurements shall be made at the time it is first encountered during drilling, the end of the workday, beginning of the workday prior to continuing to drill, and prior to completion of the drill hole.

The Contractor’s QFR shall develop drill hole logs that contain the following information at a minimum: drill hole name, dates of drilling, completion details, drill hole location (surveyed coordinates and ground surface elevation), drill rig, drill equipment specs, SPT hammer energy transfer measurement, field personnel, drilling methods, drilling conditions, depth(s) of groundwater and date(s) encountered, maximum depth of drilling, geologic unit or origin for each material encountered, depths of contacts between soil types, depths of contacts between fill materials and underlying geologic units, basis for identifying the location of contact between embankment fill and underlying foundation materials (e.g. measured embankment height, material characteristics, etc.), Unified Soil Classification System (USCS) soil descriptions and symbols (per ASTM D2487 and D2488) for each soil strata encountered based on visual-manual and laboratory classifications, sample recovery, laboratory results for each sample tested, and additional notes regarding drilling and sampling details and conditions encountered.

The Contractor’s QFR shall provide notes in the logs including percentage of fines, sand, gravel, cobbles, and boulders; particle shape and size, characterization of plasticity, toughness, dry strength and dilatancy; maximum particle size; color; moisture; reaction to dilute hydrochloric (HCl) acid (one part 10 N HCl to 3 parts distilled water); relative density and consistency; difficulty of drilling; and any other pertinent information.

Pocket penetrometers shall be performed on all intact fine-grained soils collected in the FADC. In the case of MR drilling where FADC is not performed, pocket penetrometers can be performed on SPT samples. A minimum of three pocket penetrometer tests should be performed per collected fine-grained soil sample.

Bedrock is not expected to be encountered during the performance of this scope of work. If bedrock is encountered the Contractor’s QFR shall notify the COR for direction. The Contractor’s QFR shall document within the log the depths of any suspected voids, cobbles or boulders, organic materials, debris, or anthropogenic fill materials encountered during drilling.

The Contractor’s QFR shall include drill hole and observation well completion information in the drill hole logs, with depths referenced from the ground surface at each drill hole. In the logs for drill holes completed as observation wells, the Contractor’s QFR shall include detailed as-built information regarding all material types and quantities used, and depths of placement. In the logs for drill holes not completed as observation wells, the Contractor’s QFR shall include detailed information regarding the types and volumes of backfill materials used and depths of placement, and description of materials used for surface completion. Drill holes not completed as observations wells should be backfilled to the ground surface with bentonite as approved by the COR.

The Contractor shall submit a drill hole log template with the Drill Hole Sampling Plan submittal, indicating the information to be provided for each drill hole, for approval by the COR prior to drilling activities.

All drill hole logs shall be peer reviewed by an experienced and qualified Certified Engineering Geologist (CEG) or Professional Geologist (PG) registered in the State of California prior to submittal. All draft drill hole logs should be submitted to the COR on a weekly basis and include all holes drilled from the prior week.

e. Photography

The Contractor shall document all work activities with color photographs. Photographs from each exploration shall be appended to the Geotechnical Data Report and complete digital files, including all unique photographs of the exploration activities and samples collected, and shall be transmitted to the COR with interim data deliverables. The Contractor shall annotate each photograph included in the report with the following information (as applicable): project name, drill hole ID, sample ID and depth interval, subject of photograph, photographer, and date.

The Contractor’s QFR shall photograph the soil while still within the split barrel sampling equipment, record the depth of each material change, geologically log each soil type present per Section D below, and collect samples for potential laboratory testing.

At a minimum, the Contractor shall photograph:

· Each drill hole work site, both before work starts, during work to demonstrate equipment setup on site, and after completion of the observation wells or backfill and asphalt repairs.

· Each SPT and FADC sample while still within the sampling equipment, and

· each core box used to retain FADC soil not retained for sampling, clear labeling of hole ID and depth.

· A measuring tape, for scale, is required in all photographs.

f. Storage

The Contractor will store all core boxes and excess samples not selected for immediate laboratory testing in a Conex box located at the Check 21 Structure property as outlined in Section 4.0.

2. Undisturbed (Intact) Sampling (UD)

a. General

This task includes drilling and sampling up to 50 UD hole locations according to the procedures defined herein. In addition to UD sampling, 15 UD drill holes will be selected for in-situ Vane Shear Testing (VST). The price schedule includes a performance incentive for 6 of the UD hole locations. The Contractor shall be responsible for utility location and clearance for all drilling activities. The Contractor shall provide a health and safety plan (HASP) and schedule of drilling as approved by Reclamation (see Section 11.0)

Oversight shall be performed by a QFR whom shall be onsite to monitor all work and shall be responsible for collecting data during drilling and sampling, soil classification and description, sample preservation, and backfill of the drill holes. The Contractor shall provide one QFR at each drill rig, who shall be present full time during the work at each drill hole location. The Contractor shall provide multiple QFR’s (i.e., one per drill hole) if work is performed concurrently at multiple drill holes.

The Contractor shall provide adequate equipment to allow for the below tasks. For drill holes located within orchards, the Contractor shall utilize equipment that will fit within orchard rows and minimize damage to trees (e.g., CME 45 trailer or track mounted drill rig). The UD drill holes will be performed companion (i.e., adjacent) to SPT drill holes at a distance of 5 to 10 feet away. All drilling must occur within the pre-approved work areas.

UD and VST intervals will be identified by Reclamation following the review of draft drill logs from SPT drill holes and Cone Penetration Test (CPT) soundings. Prior to sampling, submit draft geologic logs of the companion drill holes to Reclamation one week prior to execution of the UDs for selection of sample intervals. UD locations will be provided concurrently with intact sample requests from Reclamation. The Contractor shall backfill, and level all drill holes according to the procedure as outlined herein.

b. Drilling Equipment and Methods

i. Equipment

The Contractor shall provide the equipment necessary to allow for the below sampling methods in relevant drill holes and to provide adequate soil samples for the specified laboratory testing of samples from drill holes. For drill holes located within orchards, the Contractor shall utilize equipment that will fit within orchard rows and minimize damage to trees (e.g., CME 45 trailer or track mounted drill rig).

The Contractor is responsible for providing all labor, materials and equipment that can access hole locations with minimal impact to the subgrade (e.g., rutting, potholes, etc.), existing trees or crop rows. Some hole locations may only be accessible during the fall/winter due to the potential impacts drilling activities can have on existing crops which will be discussed and scheduled appropriately in the bi-weekly coordination meetings with Reclamation. Additionally, many locations will be within wetland or riparian corridors and require access in muddy, wet, or inundated areas which may require the use of track mounted equipment.

ii. Methods

UD drill holes will be advanced using hollow-stem flight auger methods similar to the SPT drill holes according to ASTM D6151 and/or ASTM D5783. FADC may be used to advance through materials where UD and VST are not performed, but pilot bit drilling is also acceptable. FADC will be performed to overcore VST intervals for sample collection. Mud Rotary (MR) will be required if flowing sands are encountered as previously discussed in the SPT drill hole task. The Contractor shall either use a direct push or hydraulically operated stationary piston sampler to advance thin-walled steel sample stubes (i.e., Shelby tubes) through the hollow-stem augers for all UD sampling.

The method will depend on the groundwater and soil conditions at the time of sampling. Above the ground water table and if soil conditions allow, direct push methods will be utilized and below the ground water table, hydraulically operated piston sampler methods will be utilized. The Contractor shall perform direct push methods in accordance with ASTM D1587 and piston sampling methods in accordance with ASTM D6519. UD sampling intervals shall be a minimum of 2 feet and cannot be performed consecutively (i.e., drill hole clean out via FADC or pilot bit is required between UD samples). Outside diameter of augers used for exploratory drill holes shall not be greater than 12 inches.

All VST must be performed below the water table at the time of drilling in accordance with ASTM D2573. Use of slip-coupling located directly above of the vane is required for measuring rod friction. Selection of the nominal vane size and geometry will pre-determined by Reclamation upon review of the companion SPT drill hole and CPT information. The exact measurements of the vane used will be measured in the field by the QFR. Depths of the VST testing will be recorded as one number referencing the location of the tip of the vane. Peak undrained strength testing (i.e., in-situ) will be performed as well as residual undrained strength testing at the same depth. This requires manually rotating the vane 10 revolutions after the peak strength test is completed (with no advancement of the vane). Note that the slip-coupling will need to be reversed (rotate rods backwards about ¼ revolution) prior to performed the residual strength test to ensure measurement of rod friction. The QFR must ensure that:

· All testing is performed at minimum distance (i.e., depth) of 2 feet below the auger or casing (i.e., where drilling ceased). This distance shall be recorded.

· Testing (i.e., rotation of the rods) commences within 5 minutes of the vane advancement

· The vane rods will be rotated at a constant rate of 6 degrees/minute.

· A bulk sample of the material tested at each depth interval is collected.

c. Sampling

i. Undisturbed/Intact The Contractor shall perform intact (UD) sampling with 5-inch outside diameter Shelby tubes at depths pre-determined by Reclamation upon review of the companion SPT drill holes. The Contractor should be equipped to collect a minimum of two (2) and a maximum of ten (10) intact samples at unique depths within each drill hole. Depths will not exceed those achieved by the companion SPT drill hole. During advancement of the UD samples, the Contractor’s QFR shall record the maximum pressure of the rig hydraulic down pressure system during direct push methods and the systems maximum water pressure during piston sampler methods, photograph the soil samples while still within the sampling equipment, and describe each soil type encountered according to USCS visual-manual classification methods specified in ASTM D2488. Sample trimming, measurement (i.e., field tube density), sealing and labeling techniques shall follow Section 8 of ASTM D1587. A water content sample from the top and bottom of the tube (once slough or ends exposed to drilling fluid and/or ground water is removed) shall be preserved in air-tight containers similar to those described in Task 1 for SPT sampling.

The Contractor’s QFR shall label, preserve, and transport all UD samples for potential geotechnical laboratory testing according to ASTM D4220, Group D. Samples shall be stored and transported in a sample box conforming to Figure 2 of ASTM D4220 including tube density, water content, o-ring gaskets etc. The Contractor shall not allow any samples to freeze or be subjected to excessive heat or vibration. Samples should be handled and stored in the vertical direction in which they were advanced

ii. VST Interval Sample

All intervals in which VST were performed shall be sampled using appropriate methods. The Contractor’s QFR shall photograph the soil samples while still within the sampling equipment (particularly looking for signs of the vane shear surface) and describe each soil type encountered according to USCS visual-manual classification methods specified in ASTM D2488. The Contractor’s QFR shall label, preserve, and transport all VST overcore/bulk samples for potential geotechnical laboratory testing according to ASTM D4220, Group B. The Contractor shall not allow any samples to freeze or be subjected to excessive heat.

d. Geologic Logging

The Contractor’s QFR shall maintain the provided naming convention for each drill hole that includes the sampling method (UD), the last two digits of the year of exploration, and the drill hole number according to the naming convention provided by the COR.

The Contractor’s QFR shall collect all required exploration data to develop drill hole logs. The Contractor’s QFR shall document the depth to groundwater, if encountered, using an electronic water level sounding device and note date, time and depth of auger when reading is taken, whether measured during or after drilling, and any other information that may affect the groundwater level measurements. Ground water measurements shall be made at the time it is first encountered during drilling, the end of the workday, beginning of the workday prior to continuing to drill, and prior to completion of the drill hole.

The Contractor’s QFR shall develop drill hole logs that contain the following information at a minimum: drill hole name, dates of drilling, completion details, drill hole location (surveyed coordinates and ground surface elevation), drill rig, drill equipment specs, field personnel, drilling methods, drilling conditions, depth(s) of groundwater and date(s) encountered, maximum depth of drilling, geologic unit or origin for each material encountered, depths of contacts between soil types, depths of contacts between fill materials and underlying geologic units, basis for identifying the location of contact between embankment fill and underlying foundation materials (e.g. measured embankment height, material characteristics, etc.), USCS soil descriptions and symbols (per ASTM D2487 and D2488) for each soil strata encountered based on visual-manual and laboratory classifications, sample recovery, laboratory results for each sample tested, and additional notes regarding drilling and sampling details and conditions encountered.

The Contractor’s QFR shall provide notes in the logs including percentage of fines, sand, gravel, cobbles, and boulders; particle shape and size, characterization of plasticity, toughness, dry strength and dilatancy; maximum particle size; color; moisture; reaction to dilute HCl acid (one part 10 N HCl to 3 parts distilled water); density and consistency; difficulty of drilling; and other pertinent information.

Handheld shear device testing shall be performed in accordance with ASTM D8121 at the bottom of each intact fine-grained sample (Shelby Tube) prior to sample preparation.

Bedrock is not expected to be encountered during the performance of this scope of work. If bedrock is encountered, the Contractor’s QFR shall notify the COR for direction. The Contractor’s QFR shall document within the log the depths of any suspected voids, cobbles or boulders, organic materials, debris, or anthropogenic fill materials encountered during drilling.

Drill hole shall be completed using approved methods prescribed in Section 7.E. The Contractor’s QFR shall include drill hole completion information in the drill hole logs, with depths referenced from the ground surface at each drill hole The Contractor’s QFR shall include detailed information regarding the types and volumes of backfill materials used and depths of placement, and description of materials used for surface completion.

The Contractor shall submit a drill hole log template with the Drill Hole Sampling Plan submittal, indicating the information to be provided for each drill hole, for approval by the COR prior to drilling activities.

All drill hole logs shall be reviewed by an experienced and qualified Professional Geologist (PG) in the State of California prior to submittal.

e. Photography

The Contractor shall document all work activities with color photographs. Photographs from each exploration shall be appended to the Geotechnical Data Report and complete digital files for all unique photographs of the exploration activities and samples collected shall be transmitted to the COR with interim data deliverables. The Contractor shall annotate each selected photograph that is included in the report with the following information (as applicable): project name, drill hole ID, sample ID and depth interval, subject of photograph, photographer, and date.

At a minimum, the Contractor shall photograph:

· A measuring tape, for scale, is required in all photographs.

3. Observation Wells (OW)

a. General This task includes drilling of up to 34 OW hole locations according to the procedures defined herein. Oversight shall be performed by a QFR whom shall be onsite to monitor all work and shall be responsible for collecting data during drilling and sampling, soil classification and description, sample preservation, and backfill of the drill holes. The Contractor shall provide one QFR at each drill rig, who shall be present full time during the work at each drill hole location. The Contractor shall provide multiple QFR’s (i.e., one per drill hole) if work is performed concurrently at multiple drill holes.

The Contractor shall obtain permits for completion of the identified groundwater OWs. The Contractor shall design and construct the OWs based on the conditions encountered and in accordance with all permit requirements, California Department of Water Resources Well Standards, and relevant manufacturer’s recommendations, to allow observation of groundwater levels in the drill holes (initial reading by Contractor subsequent readings by others) after drilling.

The Contractor shall provide a health and safety plan (HASP) and schedule of drilling. The Contractor shall be responsible for utility location and clearance for all drilling activities. The Contractor may determine that the location provided is not accessible due to existing structures or crops allowing the contractor to move the hole to the nearest accessible location. Before any holes are relocated, the Contractor shall provide the COR with a written description of the need for relocations and the proposed location of the new holes. The Contractor shall proceed with drilling the relocated hole only after receiving approval of the COR. All drilling must occur within the pre-approved work areas. The Contractor shall backfill and level all drill holes according to the procedure as outlined herein.

b. Drilling Equipment and Methods

i. Equipment

The Contractor is responsible for providing equipment that can access hole locations with minimal impact to existing trees or crop rows. Some hole locations may only be accessible during the fall / winter due to potential impacts drilling activities can have on existing crops. Additionally, many locations will be within wetland or riparian corridors and require access in muddy, wet, or inundated areas.

ii. Methods

Observation wells shall be constructed of minimum 2-inch diameter slotted PVC pipe surrounded by a sand filter pack and sealed above the sand filter pack with hydrated bentonite chips and a concrete surface seal. Unless otherwise specified, assume that all observation wells shall extend to full depths of the drill holes. The Contractor shall install a traffic-rated, flush-mounted steel manhole with lockable cover and concrete collar at each observation well and provide at least two (2) key(s) to Reclamation. The concrete collars shall be sloped to drain away from the manhole to prevent storm water runoff collecting in the manhole.

c. Sampling

The Contractor shall develop and complete the observations wells and take at least one reading of the groundwater level within each observation well following completion and stabilization of the groundwater level using an electronic water level sounding device.

d. Geologic Logging

The Contractor shall maintain the provided naming convention for each drill hole and OW that includes the type of exploration, the last two digits of the year of exploration, and the number of the OW according to the naming provided by the COR.

The Contractor’s QFR shall collect all required exploration data to develop drill hole logs. The Contractor’s QFR shall document the depth to groundwater, if encountered, as measured during or after drilling using a using an electronic water level sounding device.

The Contractor’s QFR shall develop drill hole logs that contain the following information at a minimum: drill hole name, dates of drilling, completion details, drill hole location (GPS coordinates and approximate ground surface elevation), drill rig, hammer energy transfer measurement, field personnel, drilling methods, drilling conditions, depth(s) of groundwater and date(s) encountered, maximum depth of drilling, geologic unit or origin for each material encountered, depths of contacts between soil types, depths of contacts between fill materials and underlying geologic units, basis for identifying the location of contact between embankment fill and underlying foundation materials (e.g. measured embankment height, material characteristics, etc.), USCS soil descriptions and symbols for each soil strata encountered based on visual-manual and laboratory classifications, sample recovery, laboratory results for each sample tested, and additional notes regarding drilling and sampling details and conditions encountered.

The Contractor’s QFR shall provide notes in the logs including percentage of fines, sand, gravel, cobbles, and boulders; characterization of plasticity, toughness, dry strength and dilatancy; maximum particle size; color; moisture; reaction to dilute HCl acid; density and consistency; difficulty of drilling; and other pertinent information. For any bedrock encountered, the Contractor’s QFR shall provide a description of the rock recovered including type of rock, degree of weathering, grain size, color, and hardness or strength estimate. The Contractor’s QFR shall document the depth(s) of groundwater and date(s) encountered in the log if groundwater is encountered during drilling. The Contractor’s QFR shall document within the log the depths of any suspected voids, cobbles or boulders, organic materials, debris, or anthropogenic fill materials encountered during drilling.

The Contractor’s QFR shall include drill hole and observation well completion information in the drill hole logs, with depths referenced from the ground surface at each drill hole. In the logs for drill holes completed as observation wells, the Contractor’s QFR shall include detailed as-built information regarding all material types and quantities used, and depths of placement. In the logs for drill holes not completed as observation wells, the Contractor’s QFR shall include detailed information regarding the types and volumes of backfill materials used and depths of placement, and description of materials used to repair to the asphalt paving.

The Contractor shall submit a drill hole log template with the Drill Hole Sampling Plan submittal, indicating the information to be provided for each drill hole, for approval by the COR prior to drilling activities.

All drill hole logs shall be reviewed by an experienced and qualified Certified Engineering Geologist (CEG), or Professional Geologist (PG) registered in the State of California prior to submittal.

e. Observation Well Completion

Drill holes completed as observation well shall be coordinated with COR prior to performing the work. In general, the screening depths should extend at least 18 feet below the encountered ground water level. The well pipe shall consist of 2-inch diameter PVC blank riser pipe for casing; a slotted 20 foot long well screen with 0.010-inch slot size; and a 2-inch diameter glued well cap with a two-foot blank sump. Top of the well casing should be closed with a removable PVC cap and sealed with vacuum plug, enclosed in a flush-mounted manhole vault, or a surface standpipe (as appropriate), secured with a concrete pad. Filter pack will consist of clean #20/40 size or other suitable sand extending at least 1-foot above the top of the screen. The annulus above the filter pack should be sealed with rehydrated bentonite chips or bentonite slurry. Bentonite should be used to backfill to surface. Document each well installation with an as-built well construction diagram. Develop each well post-construction by hand and document with Reclamation well development form. Well development shall be in accordance with ASTM D5521. An observation well completion and development plan shall be submitted to the COR or approval.

f. Photography

The Contractor shall document all work activities with color photographs. Photographs from each exploration shall be appended to the Geotechnical Data Report and complete digital files for all unique photographs of the exploration activities and samples collected shall be transmitted to the COR with interim data deliverables. The Contractor shall annotate each selected photograph that is included in the report with the following information (as applicable): project name, drill hole ID, sample ID and depth interval, subject of photograph, photographer, and date.

At a minimum, the Contractor shall photograph:

· Each drill hole work site, both before work starts and after completion of the backfill and asphalt repairs,

· Each Shelby tube sample while still within the sampling equipment (from each end after trimming).

· A measuring tape, for scale, is required in all photographs.

4. Cone Penetration Test (CPT)

a. General

This task includes performing up to 60 CPT sounding locations. The Contractor shall be responsible for utility location and clearance for all drilling activities. The contractor shall provide a health and safety plan (HASP) and schedule of drilling as approved by Reclamation (see Section 11.0).

Oversight shall be performed by Qualified Field Representative who shall be onsite to monitor all work and shall be responsible for collecting data during the sounding and oversee hole completion. The Contractor shall provide one QFR at each CPT rig, who shall be present full time during the work at each sounding location. The Contractor shall provide multiple QFR’s (i.e., one per CPT sounding) if work is performed concurrently at multiple sounding locations.

The Contractor shall provide adequate equipment to allow for the below tasks. For drill holes located within orchards, the Contractor shall utilize equipment that will fit within orchard rows and minimize damage to trees (e.g., probe/track mounted CPT rig). The Contractor may determine that a location provided is not accessible due to existing structures or crops. If/when this occurs, the contractor may submit a request/suggestion for moving the sounding to the nearest accessible location. Before any soundings are relocated, the Contractor shall provide the Contracting Office Representative (COR) with a written description of the need for relocations and applicable photographs of obstacle(s), proposed location(s) for the sounding(s), and a map with the original and proposed location(s). The Contractor shall proceed with pushing at the relocated sounding only after receiving approval of the COR. All soundings must occur within the pre-approved work areas. The Contractor shall backfill, and level all sounding holes according to the procedure as outlined herein.

b. Equipment and Methods

i. Equipment

The Contractor shall provide the equipment necessary to perform CPT. For soundings located within orchards, the Contractor shall utilize equipment that will fit within orchard rows and minimize damage to trees (e.g., trailer or track mounted CPT rig). The CPT rig used must be at least 20 tons in weight or be able to apply an effective equivalent down pressure if using augers to anchor the rig into the ground. Additionally, many locations will be within wetland or riparian corridors and require access in muddy, wet, or inundated areas which may require the use of track mounted equipment.

The Contractor is responsible for providing all labor, materials and equipment that can access hole locations with minimal impact to the subgrade (e.g., rutting, potholes, etc.), existing trees or crop rows. Some hole locations may only be accessible during the fall/winter due to the potential impacts drilling activities can have on existing crops which will be discussed and scheduled appropriately in the bi-weekly coordination meetings with Reclamation

ii. Methods

The Contractor shall perform CPTs in accordance with ASTM D5778 using a piezocone at each of the approximate CPT locations provided by the COR, with dynamic pore pressure measurements in all the CPTs and pore pressure dissipation testing in those CPTs specified by the COR. The Contractor shall commence testing at a depth no greater than 3 feet below the ground surface (which may be pre-drilled) and attempt to advance the CPTs to the target depths provided for each CPT, or terminate the CPT at practical refusal depth if less than full target depth. Reasons for refusal may be cone inclination, excessive tip pressure or sleeve friction, or lifting of the rig. If refusal in met within 20 feet of depth, the contractor shall retract the cone and attempt a re-push 5 feet away from the initial sounding. The CPT cone used shall not be larger than 1.75-inches in diameter. Current calibration data on the cone(s) used shall be provided to the COR. In addition, baseline sensor readings prior to the sounding and post-sounding shall be provided to the COR. If differences in baseline readings are outside the specification of ASTM D5778, the sounding must be re-pushed with a different cone, or the same cone after a manufacturer calibration.

Where requested, the Contractor shall perform downhole seismic cone testing in select CPTs in accordance with ASTM D7400, with measurements at depth intervals not greater than 5 feet and not less than 3 feet. Seismic testing locations will be selected by the COR or government representative. Up to 10 seismic testing is proposed; however, is subjected to change based on actual conditions in the field.

Pore pressure dissipation testing shall be performed using a Type II piezocone in both fine and coarse-grained layers below the ground water table. At least one pore pressure dissipation test shall be performed below the water table per CPT and one additional dissipation test per each 15 feet of saturated CPT depth. An attempt should be made to perform about half the tests in fine-grained material and half the tests in coarse-grained material. Tests shall be run to pore pressure equilibrium (no change with pressure over approximately 3 minutes) or terminated at 60 minutes duration if equilibrium is not reached. The down pressure shall be maintained during dissipation testing without movement of the cone by clamping the CPT rods to avoid unloading causing an associated drop in pore pressure.

Upon completion of the sounding and removal of the rods, the contractor shall probe the sounding hole with an electronic water sounding device to measure depth of collapse and water level (if available).

c. Hole Completion

Completion of the hole will be performed by funneling #8 Bentonite chips downhole to the surface of the existing ground. If soil conditions are dry below a depth of 5 feet, water should be introduced to the activate the bentonite.

d. Geologic Logging

The Contractor shall maintain the provided naming convention for each sounding that includes the type of exploration (CPT), the last two digits of the year of exploration, and the number of the CPT.

The Contractor shall develop CPT logs that contain the following information at a minimum: CPT name; dates of testing; completion details; CPT location (surveyed coordinates and ground surface elevation); field personnel; testing methods; type and size of cone and ID; pre-drilled depths (when applicable); maximum depth of testing; hole collapse and ground water level post-test; and test results plotted by depth interval, including tip resistance, sleeve friction, friction ratio, dynamic pore pressure, pore pressure dissipation test results, soil behavior type, and seismic wave velocities (where applicable). CPT logs shall include comments regarding the reason for termination if not advanced to full depth and any indications of gravel or coarser materials encountered. All raw CPT data collected shall be submitted in digital form along with the CPT logs.

e. Photography

The…