SAES-A-114

Engineering Standard SAES-A-114 SAES-A-114

30 September 2014

Excavation and Backfill Document Responsibility: Responsibility: Geotechnical Standards Standards Committee Committee

Saudi Aramco DeskTop Standards Table of Contents 1

Scope............................................................ . 2

2

Conflicts and Deviations......................... Deviations................................ ....... . 2

3

References.................................................... . 2

4

Definitions..................................................... . 4

5

General......................................................... . 6

6

Fill and Backfill......................... Backfill....................................... ................... ..... . 12

7

Excavation.................................................. . 21

 APPENDIX - Summary of Fill Placement and Compaction Requirements……… 24

Previous Issue: 23 February 2010

Next Planned Update: 30 September 2019 Page 1 of 25

Primary contact: Grosch, Jonathan Joseph on +966-13-8809690 Copyright©Saudi Aramco 2014. All rights reserved.

Document Responsibility: Geotechnical Standards Committee Issue Date: 30 September 2014  Next Planned Update: 30 September 2019

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SAES-A-114 Excavation and Backfill

Scope This Engineering Standard defines the requirements for excavation, plac ement, compaction, inspection, and management of earth and rock materials during construction and/or maintenance.

2

3

Conflicts and Deviations 2.1

Any conflicts between this Specification and other applicable Saudi Aramco Materials System Specifications (SAMSSs), Engineering Standards (SAESs), Standard Drawings (SASDs) or industry standards, codes, and forms shall be resolved in writing by Saudi Aramco through the Manager, Consulting Services Department.

2.2

Direct all requests to deviate from this Specification in writing to the Company Representative, who shall follow internal company procedure SAEP-302 procedure SAEP-302 and forward such requests to the Manager, Consulting Services Department of Saudi Aramco, Dhahran.

References The selection of material and equipment, and the design, construction, maintenance, and repair of equipment and facilities covered by this Stand ard shall comply with the latest edition of the references listed below, unless otherwise noted. 3.1

Saudi Aramco References Saudi Aramco Engineering Procedure SAEP-302

 Instructions for Obtaining a Waiver of a Mandatory Saudi Aramco Engineering Requirement

Saudi Aramco Engineering Standards SAES-A-100

Survey Coordinates, Datum's and Data Formats

SAES-A-113

Geotechnical Engineering Requirements

SAES-L-450

Construction of on-Land and Near-Shore Pipelines

SAES-L-460

 Pipeline Crossings under Roads and Railroads

SAES-Q-001

Criteria for Design and Construction of Concrete Structures

SAES-Q-006

 Asphalt  Asphalt and Sulfu Sulfurr Extende Extended d Asphal Asphaltt Concre Concrete te Paving Paving

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SAES-A-114 Excavation and Backfill

SAES-Q-007

 Foundations and Supporting Structures for Heavy  Machinery

SAES-P-104

Wiring Methods and Materials

SAES-S-070

 Installation of Utility Piping Systems

Saudi Aramco General Instructions GI-1021.000

Street and Road Closure: Excavation, Reinstatement and Traffic Controls

Saudi Aramco Manuals Construction Safety Manual  Blasting Manual Saudi Aramco Safety Management Guide Guide No. 06-002-2008 3.2

Excavations and Shoring

Industry Codes and Standards American Concrete Institute (ACI)

 ACI 229R

Controlled Low-Strength Materials

American Society for Testing and Materials  ASTM C136

Standard Test Method for Sieve Analysis of Fine and Coarse Aggregates

 ASTM D422

Standard Test Method for Particle-Size Analysis of Soils

 ASTM D1140

Standard Test Method for Amount of Material in Soils Finer than the No. 200 (75-um) Sieve

 ASTM D1556

Standard Test Method for Density and Unit Weight of Soil in Place by the Sand-Cone Method

 ASTM D1557

Standard Test Method for Laboratory Compaction Characteristics of Soil Using Modified Effort 56,000 ft-lbf/ft³ (2,700 KN- M/M³)

 ASTM D2167

Standard Test Method for Density and Unit Weight of Soil in Place by the Rubber Balloon Method

 ASTM D2487

Standard Practice for Classification of Soils for  Engineering Purposes (Unified Soil Classification System)

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SAES-A-114 Excavation and Backfill

 ASTM D2937

Standard Test Method for Density of Soil in Place by the Drive-Cylinder Method

 ASTM D4253

Standard Test Method for Maximum Index Density and Unit Weight of Soils Using a Vibratory Table

 ASTM D4254

Standard Test Method for Minimum Index Density and Unit Weight of Soils and Calculation of  Relative Density

 ASTM D4318

Standard Test Method for Liquid Limit, Plastic  Limit and Plasticity Index of Soils

 ASTM D5777

Standard Guide for Using the Seismic Refraction  Method for Subsurface Investigation

 ASTM D6938

Standard Test Methods for In-Place Density and Water Content of Soil and Soil-Aggregate by  Nuclear Methods (Shallow Depth)

 ASTM D7380

Standard Test Method for Soil Compaction  Determination at Shallow Depths Using 5-lb (2.3 kg) Dynamic Cone Penetrometer

 ASTM D7830/  D7830M

Standard Test Method for In-Place Density (Unit Weight) and Water Content of Soil Using an  Electromagnetic Soil Density Gauge

Definitions Brackish Water: Water with Total Dissolved Solids of 10,000 ppm or more. Clean Sand: Soil meeting the following gradation containing less than 3% weight of organic material or clay: Sieve Size

Percent Passing

¼ in (6.25 mm)

100

No. 10 (2.00 mm)

90 - 100

No. 200 (0.075 mm)

10 or less

Company Representative: Saudi Aramco's authorized representative with overall authority and responsibility for the project. Contract or Contract Documents: Any and all documents, including design drawings, which Saudi Aramco has transmitted or otherwise communicated, either by incorporation or by reference, and made part of the legal contract or purchase order agreement between Saudi Aramco and the Contractor. Page 4 of 25

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SAES-A-114 Excavation and Backfill

Contractor: The party responsible for performing excavation and backfill, including work executed through the use of sub-contractors Controlled Low Strength Material (CLSM): A flowable, self-compacting, cementitious material used primarily as a backfill in place of compacted fill. Dune Sand: Wind-deposited sand consisting of relatively single-sized particles generally passing the No. 16 sieve (1.18 mm) and usually containing less than 10% soil  particles passing the No. 200 sieve (0.074 mm). Fill Material: See General Fill Material. General Fill Material: Inorganic soil or rock meeting the requirements in Section 6.1.1. Hard Rock: Rock that cannot be excavated using typical excavation equipment. See Rock Excavation, Section 7.5. Marl: is a wide variety of calcareous soil materials found in Saudi Arabia which may vary from clay to gravel sizes and often include cobble and boulder sized pieces. Rock: “Rock ” may refer to anything from boulder-size individual pieces to hard, intact  bedrock. See section 7.5 for classification of rock by excavation methods. Sabkha: is a saline (generally coastal) deposit generally consisting of saturated, loose silty sand and possibly clay. Select Fill Material: Gravel, sand, clay, or silt, or a mixture of these constituents meeting the requirements in Section 6.1.2. Soft Rock: Weak and fractured rock formations that can be excavated using typical excavation equipment. See Normal Excavation, Section 7.5. Stable Rock:  Natural solid mineral matter that can be excavated with vertical sides and remain intact while exposed. It is usually identified by a rock name such as limestone or sandstone. Structural Fill: Select Fill Material as per Section 6.1.2. Vibrating or Heavy Machinery: Centrifugal rotating machinery greater than 500 horsepower, reciprocating machinery greater than 200 horsepower, and all table-top special purpose equipment.

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General 5.1

Quality Control The Contractor shall institute a quality control program that will verify or ens ure that the work performed under the Contract me ets the requirements of this Standard and the Contract Documents. Saudi Aramco shall have access to all facilities and records of the Contractor for the purpose of conducting  performance inspection/audits. During the audit, any inspection, test reports, and/or engineering analyses and calculations associated with the scope of work shall be furnished upon request. Inspection & Testing Agency

5.2

5.1.1

The Contractor's quality control testing requirements shall be performed  by either a Saudi Aramco-approved independent testing agency or by the Contractor's own laboratory, approved by the Saudi Aramco Inspection Department.

5.1.2

All required laboratory and field acceptance tests required in Section 6.4 and all seismic refraction testing required in Section 7.5 shall be  performed by a Saudi Aramco-approved independent testing agency.

5.1.3

If testing and/or inspection is done by Saudi Aramco, this does not relieve the Contractor of the responsibility to meet all requirements of this Standard. Should it be later found that some work has been completed not in compliance with this Standard, it shall remain the Contractor's responsibility to repair or reconstruct deficient work until specifications are met at no cost to Saudi Aramco.

Submittals The Contractor shall be responsible for transmitting the following submittals to the Saudi Aramco Company Representative: 5.2.1

Compaction Test Reports, including all laboratory and field test logs and comments. Field test reports shall include density and moisture content test logs indicating location by coordinates and elevation as per SAES-A-100. Reports shall be submitted as follows: 5.2.1.1

Daily “ pass” or “fail” reports.

5.2.1.2

A summary report with test logs shall be submitted weekly or as required by Saudi Aramco.

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5.2.1.3

SAES-A-114 Excavation and Backfill

A complete record of all test logs and comments for  permanent project records shall be submitted at earthwork completion.

5.2.2

Fill Materials and Water Test Reports. Sources and test results of all fill materials and compaction water shall be submitted for approv al prior to  beginning fill operations. Compaction water shall be tested for Total Dissolved Solids, Chloride (Cl ) and Sulfate (SO4) contents according to SAES-Q-001.

5.2.3

Controlled Low Strength Material (CLSM) mix design and 28-day compressive strength shall be submitted for approval prior to use o n the site.

5.2.4

Excavation Plan, including a Pre-Excavation checklist, as per the Saudi Aramco Construction Safety Manual and Safety Management Guide 06002-2008 shall be submitted prior to beginning excavation. Consulting Services Department review of the Excavation Plan is required if excavation depth is greater than 6 m or if the Plan includes support or  protection for existing structures, foundations or underground utilities. Commentary Note:  A geotechnical investigation as per   SAES-A-113 is required for excavation depths greater than 6m.

All excavations, including shoring and sheeting materials and systems, shall meet the minimum requirements established by the Construction Safety Manual and Saudi Aramco Safety Management Guide 06-0022008. If an Excavation Plan is required and shoring is used, the Contractor’s Excavation Plan shall:

5.2.5

a)

Describe the materials and shoring system to be used.

 b)

Indicate whether or not any components will remain after filling or  backfilling.

c)

Provide plans, sketches and/or detail along with calculations.

d)

Indicate the sequence and method of shoring installation and removal.

Dewatering Plan. If dewatering of an excavation is required, the Contractor shall submit proposed methods and details to the Saudi Aramco Company Representative for review and approval, before  beginning dewatering and excavation.

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Document Responsibility: Geotechnical Standards Committee Issue Date: 30 September 2014  Next Planned Update: 30 September 2019

5.3

SAES-A-114 Excavation and Backfill

Environmental 5.3.1

Contaminated Soils Known contaminated soils within the construction limits shall be managed in accordance with a contaminated soil management plan provided by Saudi Aramco prior to the start of excavation. If unexpected soil contamination is encountered during the work, the Contractor shall stop work and notify the Saudi Aramco Company Representative immediately.

5.3.2

Erosion/Sediment Control The Contractor shall ensure that all slopes and o ther areas subject to erosion shall be maintained using temporary erosion and sediment control measures during construction or until relieved by the S audi Aramco Company Representative or until permanent measures are completed and functioning in a satisfactory manner.

5.3.3

Dust Control The Contractor shall employ dust control measures during construction. The adequacy of the dust control shall be determined by the Saudi Aramco Company Representative.

5.4

Drainage and Dewatering A Dewatering Plan shall be submitted to the Saudi Aramco Company Representative as per Section 5.2.5. 5.4.1

All temporary drainage and dewatering methods and disposal of water are subject to approval by Saudi Aramco.

5.4.2

The Contractor shall employ temporary drainage measures during construction. Ponding of water on placed fill or within excavations shall not be allowed.

5.4.3

Surface water shall be prevented from flowing into excavations by ditching, trenching, forming protective swales, pumping, or other approved measures.

5.4.4

If required in the contract documents, prior to excavation, an approved dewatering system shall be installed and operated when necessary to lower the groundwater. The dewatering system shall be engineered  based on a soil and groundwater properties from a geotechnical investigation conducted as per  SAES-A-113.

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5.5

SAES-A-114 Excavation and Backfill

5.4.5

All diverted and pumped water shall flow to specified collection areas and shall be disposed of as directed by the Saudi Aramco Company Representative. Excavations for foundations and other underground installations shall not be used as temporary drainage ditches.

5.4.6

Disposal of drainage water and groundwater contaminated with oil, gasoline, diesel, solvents and/or other chemicals shall be approved by the Environmental Protection Department.

Safety and Protection The Contractor shall place and maintain in good condition temporary fences, guardrails, barricades, lights, shoring, bracing, and other protective measures required for the safety of personnel and the premises as described in the Saudi Aramco Construction Safety Manual. 5.5.1

5.5.2

Required Permits and Procedures 5.5.1.1

All necessary permits must be obtained from Saudi Aramco  prior to performing any earthwork.

5.5.1.2

All rock blasting shall follow the procedures in the Saudi Aramco Blasting Manual.

Excavation Safety An Excavation Plan shall be submitted to the Saudi Aramco Company Representative as per Section 5.2.4. All excavation and trenching shall be done in accordance with Saudi Aramco safety requirements including, but not limited to, the S audi Aramco Construction Safety Manual and Safety Management Guide 06002-2008, including: 

Provision of safe entry and exit.



Precautions for Hazardous Atmospheres and Confined Spaces.







Provision and maintenance of edge protection, clearances, barricades, and fixed lighting. Protection of underground utilities and installations. Protection against sidewall cave-in. Shoring shall be installed or the sides shall be sloped or benched when any excavation or trench reaches a depth of 1.2 m or when soil banks are greater than 1.5 m.

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SAES-A-114 Excavation and Backfill

Commentary Note: Specific requirements are given in Saudi Aramco Safety Management Guide 06-002-2008. 



5.5.3

5.5.4

Provision of proper inspection frequency. Proper backfilling and removal of shoring. Shoring ma y be left in-place if so indicated in the approved Excavation Plan.

Hazard Mitigation 5.5.3.1

Whenever Saudi Aramco determines that any excavation or embankment or fill which was created by a Contractor and which is a hazard to life and limb, or endangers property, or adversely affects the safety, use or stability of a roadwa y or drainage channel, the responsible Contractor shall immediately repair or eliminate such excavation or embankment so as to eliminate the hazard.

5.5.3.2

Any construction or maintenance work which restricts the full use of a pedestrian or vehicular roadway shall comply with GI-1021.000, Street and Road Closure: Excavation, Reinstatement and Traffic Controls.

Protection of Existing Facilities 5.5.4.1

The Contractor shall be responsible for avoiding damage to all existing facilities. Unless otherwise specified, any damage  by the Contractor during performance of the work shall be repaired or replaced by the Contractor to the satisfaction of the Saudi Aramco Company Representative at no cost to Saudi Aramco.

5.5.4.2

No excavation is permitted under existing foundations. Excavations are not allowed to intersect a 45 degree plane extending downward from the bottom edge of existing foundations unless an engineered support system, app roved as  part of the Excavation Plan, is in place prior to the start of work or the excavation is in stable rock.

5.5.4.3

Excavations adjacent to existing underground installations (e.g., piping, manholes, electrical and duct banks) or sidewalks shall use bracing and shoring to protect those installations during construction. In general, protection is required if the excavation will intersect a 45 degree plane

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Document Responsibility: Geotechnical Standards Committee Issue Date: 30 September 2014  Next Planned Update: 30 September 2019

SAES-A-114 Excavation and Backfill

extending downward from the bottom of the structure or utility to be protected.

5.5.5

5.5.4.4

Structures that require passive soil pressure for stability (e.g., light poles or tower foundations) shall be prop erly  braced whenever an excavation is within the passive pressure zone (generally a distance of 1.5 times the embedment depth of the foundation). Fill or backfill of the excavation must meet the compaction requirements in sections 6.3.6.1 or 6.3.6.2 as applicable.

5.5.4.5

All reference points, property markers, bench marks, monuments, etc., shall be carefully maintained d uring excavation, backfilling, compaction and earthwork. Unless otherwise specified, damage to a reference po int by the Contractor during performance of the work shall be reported to Saudi Aramco and repaired or replaced by the Contractor to the satisfaction of the Saudi Aramco Company Representative at no cost to Saudi Aramco.

5.5.4.6

The Contractor shall be responsible for preserving and avoiding damage to trees, shrubs, and all other vegetation in the areas beyond the designated excavation area.

Trenching through Roads and Pavements Reinstatement of roads and pavements after trenching shall compl y with SAES-Q-006 and GI-1021.000, Street and Road Closure: Excavation, Reinstatement and Traffic Controls.

5.5.6

Clean Up 5.5.6.1

Soil that is spilled or washed onto paved areas or streets shall  be removed daily or as directed by the Saudi Aramco Company Representative.

5.5.6.2

Soil that is spilled or washed into drains, pipes, gutters, or ditches or onto adjacent sites shall be removed daily. The Contractor shall provide measures to prevent recurrence.

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SAES-A-114 Excavation and Backfill

Fill and Backfill Requirements 6.1

Fill and Backfill Materials Fill and backfill materials shall conform to the criteria in sections 6.1.1, 6.1.2, 6.1.3 and 6.1.4 below or as recommended by a geotechnical report as per SAES-A-113. All sources of supply shall be approved by Saudi Aramco. Stockpiles shall be placed, graded, and shaped for proper drainage. Storage or stockpiling of material shall not be permitted on a completed subgrade. Stockpiles of cohesive soil shall be protected from freezing. Soils shall be classified per ASTM D2487. 6.1.1

6.1.2

General Fill Material 6.1.1.1

General Fill Material shall consist of gravel, sand and/or marl. The maximum size of the fill material shall be one-half the lift thickness or 75 mm (3 inches), whichever is less.

6.1.1.2

Fill material shall be free of frozen lumps, organic matter, trash, chunks of highly plastic clay (classified as CH as determined by ASTM D2487) or other unsatisfactory material.

Select Fill Material 6.1.2.1

Select Fill or ‘Structural Fill’ shall be composed only of inorganic material and shall have 100% passing the 5 cm (2 in) sieve and from 0 to 20% passing the No. 200 sieve.

6.1.2.2

The portion of Select Fill material passing the No. 40 sieve shall have a maximum liquid limit of 35 and a maximum  plasticity index of 12 per ASTM D4318. Liquid limit and  plastic limit tests are not required for select fill material with less than 15% passing the No. 200 sieve.

Commentary Notes: Clean sand and dune sand may be used as Fill or Select Fill Material. If sand is used as fill material, see Paragraphs 6.3.3.5 and 6.3.8. Cohesionless materials (sand or gravel) are recommended for Fill or Select Fill Material below the highest natural groundwater level.

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6.1.3

SAES-A-114 Excavation and Backfill

Controlled Low-Strength Material (CLSM) 6.1.3.1

CLSM or “flowable fill” may be substituted for either Select Fill Material or general Fill Material, where approved b y the Company Representative. CLSM is recommended where traditional compaction is difficult (i.e., narrow or congested excavation backfill).

6.1.3.2

Unless otherwise specified, CLSM shall be in accordance with ACI 229R.

6.1.3.3

The mix design shall be proportioned to produce a 28-day compressive strength between 0.7 and 1.4 MPa (100 and 200 psi), pretested using the actual raw materials and approved by the Company Representative before use on the  project. Compressive strengths above or below this range may be approved by the Company Representative based on future excavation requirements. Commentary Note: Per ACI 229R: The ability to excavate CLSM is an important consideration on many projects. In general, CLSM with a compressive strength of 0.3 MPa (50 psi) or less can be excavated manually. Mechanical equipment, such as backhoes, are used for compressive strengths of 0.7 to 1.4 MPa (100 to 200 psi). Mixtures using high quantities of coarse aggregate can be difficult to remove by hand, even at low strengths. Mixtures using fine sand or only fly ash as the aggregate filler have been excavated with a backhoe up to strengths of 2.1 MPa (300 psi).

6.1.3.4

Unless otherwise specified, simple visual inspection only shall be required for field testing of CLSM.

6.1.3.5

CLSM shall be allowed to harden a minimum of 6 hours prior to proceeding with construction over the CSLM.

6.1.4

Other fill materials (e.g., rock fill, lean concrete, etc.) may be used with the approval of the Chairman, Geotechnical Standards Committee.

6.1.5

Compaction Water 6.1.5.1

Water used for compaction of fill material shall be reasonably free of salts, oil, acid, alkalis, organic matter, or o ther deleterious substances.

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6.1.5.2

SAES-A-114 Excavation and Backfill

Use of water with Total Dissolved Solids of 10,000 ppm or more (i.e., brackish water, seawater or water obtained from ground pits such as subkha water) is not allowed. Exceptions to Paragraph 6.1.5.2:  A. There is no source of acceptable water available w ithin 20 km.* B. The estimated volume of available acceptable water within 20 km could not sustain the requirement of the project or Program.* C. The fill or backfill will be below the surrounding area natural water table as determined by a geotechnical investigaton or monitoring wells. * Verified by the Company Representative. Commentary Note: Major projects and Programs which anticipate the use of brackish water or seawater shall include a holistic approach to concrete mix design requirements aligned with SAES-Q-001 Table 1 in the design planning stage. The Chloride (Cl-) and Sulfate (SO4 ) contents in the compaction water defines Exposure Type as detailed in SAES-Q-001 Table 1.

6.2

Preparation of Areas to Receive Fill, Pavement or Loads 6.2.1

Areas to receive fill, foundations, or pavement shall be free of organic material, trash, or other unsuitable material.

6.2.2

Proper drainage shall be maintained at all time so that the site is free of standing water. Any soil that becomes saturated shall be removed completely or as specified by the Company Representative.

6.2.3

Areas, in horizontal plane or side slope, shall be prepared for fill or loading as follows: 6.2.3.1

The site shall be proof-rolled and inspected for soft spots or loose zones. Proof roll may be defined as crossing the area with a heavy (minimum 10-ton weight) rubber-tire or steelwheel roller.

6.2.3.2

All observed soft spots or loose zones shall be compacted in place or excavated to firm soil and replaced with fill material compacted to the specifications in Section 6.2.3.2.

6.2.3.3

Top 150 mm scarified and recompacted. The density of the top 150 mm in these areas shall not be less than 90% of the Page 14 of 25

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maximum Modified Proctor density (ASTM D1557) or 70% relative density (ASTM D4253 and ASTM D425 4) for cohesionless freely draining soil. 6.3

Fill Placement and Compaction Commentary Note:  A summary of fill placement and compact ion requirements is included as an  Appendix to this Standard.

6.3.1

Select Fill Material shall be specified: 6.3.1.1

Within 0.6 m of the bottom elevation of foundations, spread footings, slabs-on-grade and pavements when fill is required to achieve final grade. In general, Select Fill Material shall be specified for entire lifts and not interspersed with General Fill Material within the same lift. Commentary Note: Foundations may be constructed directly on undisturbed soil. Excavation of undisturbed soil and replacement with Select Fill Material shall not be performed except as noted in 6.2.3.2 or 7.2.2 or as recommended in a geotechnical report as per SAES-A-113.

6.3.2

6.3.1.2

For backfill which will be in contact with concrete or steel structures.

6.3.1.3

All other areas not designated above or otherwise specified in as Select Fill Material in the design drawings ma y be filled or  backfilled using General Fill Material.

Before placement of fill, the area to receive the fill shall be prepared in accordance with Section 6.2. In addition: 6.3.2.1

In no case shall compaction be allowed on slopes greater than 1 (V) to 5 (H). A series of horizontal benches, steps, or terraces, at least 1 compactor width, should be cut into existing and natural slopes prior to adding new fill to key the new fill into the underlying soil.

6.3.2.2

Construction of new slopes shall be accomplished by compacting horizontal fill layers at least 1 compac tor width

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SAES-A-114 Excavation and Backfill

 beyond the design edge of the slope and then trimming back to achieve the final slope dimensions. 6.3.3

Fill material shall be placed in uniform loose lifts not exceeding the following criteria, provided that the specified compaction is a chieved for the full depth. 6.3.3.1

Select Fill Material shall be placed in lifts of 200 mm maximum in loose depth.

6.3.3.2

General Fill Material shall be placed in lifts of 300 mm maximum in loose depth.

6.3.3.3

General Fill Material and Select Fill Material shall be placed in lifts of 100 mm maximum in loose depth for hand-operated compaction equipment.

6.3.3.4

Other lift thicknesses may be approved by the appropriate Saudi Aramco Inspection Representative based on a field test section using the intended compaction equipment and verification that compaction was achieved for the full depth. Commentary Notes: Impact rollers can compact soils in lifts exceeding 1 m. See Section 6.4.2.6 for use of a method statement for compaction procedure with reduced testing requirements.

6.3.3.5

If clean sand or dune sand is used for fill, the compacted sand shall be kept wet until the next layer is placed. Commentary Note: Sand that has been allowed to dry out will uncompact under vehicle or pedestrian traffic. Continuous watering is required to maintain compaction until the next lift is in-place.

6.3.4

Compacting shall begin only after the fill or backfill has been properly  placed and the material to be compacted is at the proper moisture content. 6.3.4.1

The moisture content of the material being compacted shall  be within 3%, plus or minus, of the optimum moisture content as determined by ASTM D1557.

6.3.4.2

For cohesionless freely draining soils when ASTM D4253/ ASTM D4254 are the appropriate test procedures, there is no applicable optimum moisture content.

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6.3.5

SAES-A-114 Excavation and Backfill

Compaction shall be performed with equipment compatible with soil type. 6.3.5.1

Fill and backfill adjacent to structures such as retaining walls,  pits, and basements shall not be compacted with heavy equipment, but shall be compacted with hand-operated equipment to a distance of 1.2 meters or greater beyond the sides of the structures. Every effort shall be made to place  backfill materials symmetrically and in uniform layers to  prevent unnecessary eccentric loading on a structure or foundation.

6.3.5.2

Compaction by water jetting or flooding is not permitted for most fill material. However, flooding with positive drainage may be used if the fill material is cohesionless freely draining sand. Commentary Note: Water flooding with positive drainage may be the most effective compaction technique for poorly graded and singlesize sands, as these sands are difficult to compact with mechanical compactors.

6.3.6

Fill and backfill layers shall be uniformly compacted in accordance with the following density requirements: 6.3.6.1

All Select Fill Material and any fill beneath and/or adjacent to foundations, grade beams, mats, buildings, lined slopes o r drainage channels, and process areas: 



6.3.6.2

At least 90% of the maximum Modified Proctor density as determined by ASTM D1557, or At least 70% Relative Density as determined by ASTM D4253 and ASTM D4254 for cohesionless granular soils that do not exhibit well-defined moisture density relationship.

Select Fill Material beneath and/or adjacent to foundations with static loads over 320 kPa and foundations for vibrating or heavy machinery: 



At least 95% of the maximum Modified Proctor density as determined by ASTM D1557, or At least 85% Relative Density as determined by Page 17 of 25

Document Responsibility: Geotechnical Standards Committee Issue Date: 30 September 2014  Next Planned Update: 30 September 2019

SAES-A-114 Excavation and Backfill

ASTM D4253 and ASTM D4254 for cohesionless granular soils that do not exhibit well-defined moisture density relationship. 6.3.6.3

Asphalt and concrete pavement subgrades: 



6.3.6.4



At least 90% of the maximum Modified Proctor density as determined by ASTM D1557, or At least 70% Relative Density as determined by ASTM D4253 and ASTM D4254 for cohesionless granular soils that do not exhibit well-defined moisture density relationship.

General Fill Material for areas designated as open or landscaped: 



6.3.6.6

At least 85% Relative Density as determined by ASTM D4253 and ASTM D4254 for cohesionless granular soils that do not exhibit well-defined moisture density relationship.

General Fill Material for areas not designated as open or landscaped: 

6.3.6.5

At least 95% of the maximum Modified Proctor density as determined by ASTM D1557, or

At least 85% of the maximum Modified Proctor density as determined by ASTM D1557, or At least 65% Relative Density as determined by ASTM D4253 and ASTM D4254 for cohesionless granular soils that do not exhibit well-defined moisture density relationship.

Working platforms for compaction on subkha deposits shall be compacted as necessary to achieve a stable base. Subkha working platforms must be indicated as such and accounted for in the design. Compaction testing of working  platforms is not required. Commentary Notes: Compaction to the required densities indicated in Section 6.3 are virtually impossible to achieve in the first layer placed directly on subkha and similar very weak soils. A working  platform to provide a stable base is often required. Page 18 of 25

Document Responsibility: Geotechnical Standards Committee Issue Date: 30 September 2014  Next Planned Update: 30 September 2019

SAES-A-114 Excavation and Backfill

 A 500 mm thick layer of f ill material placed directly on t he subkha compacted as well as possible is usually sufficient. Stripping of the subkha crust   prior to fill placement is not recommended. A geotextile layer between the subkha and the working platform provides a capillary break and improves both short-term (construction) and long-term performance of the engineered fill. “  

6.3.6.7

”  

Topsoil identified as “for planting purposes” is exempted from compaction requirements.

6.3.7

Compacted surfaces of fill and backfill shall be finish graded to the cross sections, lines, grades, and elevations as indicated on the drawings.

6.3.8

Surficial erosion protection, as approved by the Company Representative, shall be provided when: 6.3.8.1

Clean sand or dune sand is used for fill, or

6.3.8.2

Final slopes are steeper than 1 (V) to 5 (H). Commentary Note: Typical surficial erosion protection includes grass/vegetation, select fill material (where required as per Section 6.3.1), cohesive marl (minimum 150mm thick, classified as SC, ML or CL as determined by ASTM D2487, compacted as per Section 6.3.6), soil-cement (minimum 5% cement by weight), chemical or polymer spray, asphalt/concrete surfacing, riprap, or geomaterials such as geocells.

6.4

Testing and Inspection Requirements 6.4.1

Laboratory Control Tests 6.4.1.1

Tests of gradation, plasticity, density, and moisture content shall be performed for each type of fill material. These tests shall include the following: Required tests for cohesive soils: 1

Sieve analysis (ASTM C136, ASTM D422 or ASTM D1140)

1

Plasticity Index determination (ASTM D4318)

1

Modified Proctor Test (ASTM D1557) with corresponding Proctor curve.

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Document Responsibility: Geotechnical Standards Committee Issue Date: 30 September 2014  Next Planned Update: 30 September 2019

SAES-A-114 Excavation and Backfill

Required tests for cohesionless soils: 1

Sieve analysis (ASTM C136, ASTM D422 or ASTM D1140)

1

Relative Density determination (ASTM D4253 and ASTM D4254).

When the backfill material cannot clearly be classified as cohesive or cohesionless both Relative Density an d Proctor density tests must be performed per the above paragraph. The backfill shall then be compacted to the greater density. 6.4.1.2

Laboratory Control Test Frequency 



6.4.2

The control tests specified in section 6.4.1.1 shall be 3 conducted at a minimum for every 10,000 m  where the fill material is uniform or for every change of source or material type. Every effort should be made to ensure that the fill material is uniform. However, in situations when the fill is (1) from a single borrow area but non-uniform in composition, or (2) a stockpile from multiple sources, the tests in section 6.4.1.1 shall be conducted at a minimum 3 for every 5,000 m  using a combined sample of four random samples of the fill material.

Field Control Tests 6.4.2.1

In-place density and moisture content of soils shall be determined by the following methods: 







6.4.2.2

Sand-cone method in accordance with ASTM D1556  Nuclear method in accordance with ASTM D2922 Rubber balloon method in accordance with ASTM D2167 Drive-cylinder method in accordance with ASTM D2937. The drive-cylinder method per ASTM D2937 may only  be used if the compacted layer is only 15 cm or less.

Other methods for in-place density of compacted fills, such as Electromagnetic Soil Density Gauge (ASTM D7830/ D7830M) or Dynamic Cone Penetration (ASTM D7380), may be approved by the Saudi Aramco Inspection Representative based on a field test which proves the Page 20 of 25

Document Responsibility: Geotechnical Standards Committee Issue Date: 30 September 2014  Next Planned Update: 30 September 2019

SAES-A-114 Excavation and Backfill

accuracy of the method for the given fill material and compaction method. 6.4.2.3

7

Testing shall be performed at the following frequencies: 1.

Select Fill Material under all foundations, buildings and  process areas - one test every 100 m² of each lift.

2.

Select Fill Material under roadways, railroads, area  pavement and parking areas, and lined slopes or drainage channels - one test every 200 m² of each lift.

3.

General Fill Material - one test every 500 m² of each lift.

4.

Backfill of trenches - one test for every 15 linear meter of each lift.

6.4.2.4

As a minimum, at least one in-place density test must be  performed on every lift of fill and further placement shall not  be allowed until the required density has been achieved.

6.4.2.5

The number of tests shall be increased if a visual inspection determines that the moisture content is not uniform or if the compacting effort is variable and not considered sufficient to attain the specified density.

6.4.2.6

The Project Inspection Representative may approve a decrease in the number of tests once a compaction procedure has proven to meet compaction requirements. In such cases, a method statement for the compaction procedure and testing frequency shall be submitted to the Saudi Aramco representative and approved by Project Inspection. The method statement must include the equipment type, serial numbers, lift thicknesses, and the number of passes required to achieve the required density.

Excavation 7.1

General Excavation General excavation shall be performed after clearing and stripped of organic material, trash, or other unsuitable material.

7.2

Structural Excavation Structural excavation shall include excavations for footings, grade beams, pits, Page 21 of 25

Document Responsibility: Geotechnical Standards Committee Issue Date: 30 September 2014  Next Planned Update: 30 September 2019

SAES-A-114 Excavation and Backfill

 basements, retaining walls, man holes, catch basins, pipeline thrust anchors, etc.

7.3

7.2.1

Excavation shall be performed as required by the design drawings to the dimensions, grades, and elevations as noted and as required for formwork and allowance for compaction equipment.

7.2.2

When soft or compressible soil is encountered at footing grades as shown on the drawings, such soil shall be removed and replaced with compacted Select Fill as specified in Sections 6.2 and 6.3, CLSM, or lean (1000 psi minimum 28-day compressive strength) concrete.

7.2.3

Over-excavation at footings shall be backfilled with compacted Select Fill as specified in Sections 6.2 and 6.3, CLSM, or lean (1000 psi minimum 28-day compressive strength) concrete.

Earthen Structures Earthen structures include permanent work items such as ponds, canals, ditches, etc. Excavation for such work shall be made to the lines, grades, and cross sections as shown on the drawings.

7.4

7.3.1

Side slopes of excavations shall be cut true and straight and shall be graded to the design cross section. Unstable soil in the slopes shall be removed and the slopes properly prepared as described in Section 6.3.2. The bottoms of excavations shall be graded to the elevations and configurations as shown on the drawings.

7.3.2

Over excavation shall be backfilled with suitable material compacted in accordance with Section 6.3, CLSM, or lean (1000 psi minimum 28-day compressive strength) concrete.

Trenching Trenching for pipelines and underground utilities shall conform to SAES-L-450, SAES-L-460, or  SAES-S-070 as appropriate. Reinstatement of roads and pavements after trenching shall comply with shall comply with SAES-Q-006 and GI-1021.000, Street and Road Closure: Excavation, Reinstatement and Traffic Controls.

7.5

Rock Excavation Seismic velocities will be the sole factor in determining the app ropriate category for the excavation of rock. Excavation of rock will fall into the following categories, based on the excavation type and the seismic compression (P) wave

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Document Responsibility: Geotechnical Standards Committee Issue Date: 30 September 2014  Next Planned Update: 30 September 2019

SAES-A-114 Excavation and Backfill

velocities measured in the field prior to excavation by refraction seismic testing as per ASTM D5777. Table 1  –   Excavation Categories Seismic Velocity from Shallow Refraction Tests (m/s) Excavation Type

Vp < 1530

1530 < Vp < 2300

Vp >2300

Small/linear 

 Normal Excavation

Rock Excavation

Rock Excavation

Mass grading

 Normal Excavation

 Normal Excavation

Rock Excavation

Where:

7.6

 Normal Excavation

Excavation that can be accomplished using rippers (mass grading) and/or excavators/backhoes (linear and isolated small excavations,) operated in accordance with good construction practice. Normal excavation includes all soils and also includes soft, weathered and/or fractured rock.

Rock Excavation

Excavation that cannot be accomplished using rippers and/or excavators/backhoes and which requires blasting or pneumatic rock breakers to facilitate excavation.

Small/linear

Isolated small excavations and linear excavations (trenches, road cuts) where limitations to ripping are present, verified  by the Company Representative. Such limitations may include ripping direction and/or travel distance.

Mass grading

Large, open area excavation where no limitations to ripping are present.

Vp

Seismic compression (P) wave velocity.

Disposal of Materials All excavated materials that are unsatisfactory for use as fill or backfill or that are surplus to that needed for backfilling shall immediately be disposed of at a location designated by the Saudi Aramco Company Representative.

30 September 2014

Revision Summary Major revision to revise compaction water requirements, add CSLM as a fill material, revise requirements for fill placement and compaction, and revise testing requirements.  Added a summary table of fill placement and compaction requirements as an Appendix. Reorganized entire document for clarity.

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Document Responsibility: Geotechnical Standards Committee Issue Date: 30 September 2014  Next Planned Update: 30 September 2019

SAES-A-114 Excavation and Backfill

APPENDIX Summary of Fill Placement and Compaction Requirements Area/Region Site preparation of areas to receive fill, pavement or loads.

Compaction Requirement The density of the top 150 mm in these areas shall not be less than: 90% of the maximum Modified Proctor density (ASTM D1557) or 70% relative density (ASTM D4253 and ASTM D4254) for cohesionless free draining soil

Comments Site preparation 









All Select Fill Material or any fill beneath and/or adjacent to grade beams, mats, buildings, lined slopes or drainage channels, and process areas.

Compacted to at least: 90% of the maximum Modified Proctor density (ASTM D1557) or 70% Relative Density (ASTM D4253 and ASTM D4254) for cohesionless granular soils that do not exhibit well-defined moisture density relationship.





Asphalt and concrete pavement subgrades (roads & parking areas).

General Fill Material not designated as open or landscaped.

Compacted to at least: 95% of the maximum Modified Proctor density (ASTM D1557). or 85% relative density (ASTM D4253 and ASTM D4254) for cohesionless granular soils that do not exhibit well-defined moisture density relationship.

Proper drainage so that the site is free of standing water all the time. In-situ soil proof rolled and inspected for soft spots or loose zones. Proof roll may be defined as crossing the area with a heavy (minimum 10-ton weight) rubber-tire or steel-wheel roller. All observed soft spots or loose zones shall  be compacted in-place or excavated to firm soil and replaced with p roperly compacted fill. Top 6 inches (150 mm) scarified and recompacted.

Fill material shall be placed in uniform loose lifts not exceeding the following criteria,  provided that the specified compaction is achieved for the full depth.



Select Fill Material beneath and/or adjacent to foundations with static loads over 320 kPa and foundations for vibrating or heavy machinery.

Areas shall be free of organic material, trash or other unsu itable material.



Select Fill Material shall be placed in lifts of 200 mm maximum in loose depth. General Fill Material shall be placed in lifts of 300 mm maximum in loose depth. General Fill Material and Select Fill Material shall be placed in lifts of 100 mm maximum in loose depth for hand -operated compaction equipment. Other lift thicknesses may be approved by the appropriate Saudi Aramco Inspection Representative based on a field test section using the intended compaction equipment. (Impact rollers can compact soils in lifts exceeding 1 m).

Compacted to at least: 90% of the maximum Modified Proctor density (ASTM D1557) or 70% Relative Density (ASTM D4253 and ASTM D4254) for cohesionless granular soils that do not exhibit well-defined moisture density relationship.

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Document Responsibility: Geotechnical Standards Committee Issue Date: 30 September 2014  Next Planned Update: 30 September 2019 Area/Region

Compaction Requirement

General Fill Material for areas designated as open or landscaped.

Compacted to at least:

Topsoil identified as “for  planting purposes.”

Exempted from compaction requirements.

Working platforms for compaction on subkha deposits.

A 500 mm thick layer of fill material placed directly on the subkha compacted as well as  possible is usually sufficient. Stripping of the subkha “crust” prior to fill placement is not recommended. A geotextile layer between the subkha and the working platform provides a capillary break and improves both short-term (construction) and long-term performance of the engineered fill.

Excavation and Backfill Comments

85% of the maximum Modified Proctor density (ASTM D1557) or 65% Relative Density (ASTM D4253 and ASTM D4254) for cohesionless granular soils that do not exhibit well-defined moisture density relationship.

Compaction testing of working platforms is not required.

Pavement Reconstruction after Trenching

SAES-A-114

Reinstatement of roads and pavements after trenching shall comply with shall comply with SAES-Q-006 and GI-1021.000.

Working platforms for compaction on subkha deposits shall be compacted as necessary to achieve a stable base. Subkha working  platforms must be indicated as such and accounted for in the design. Compaction to the required densities indicated in Section 6.3 are virtually impossible to achieve in the first layer p laced directly on subkha and similar very weak soils. A working  platform to provide a stable base is often required.

Controlled Low Strength Material (CLSM), a flowable, self-compacting fill, is recommended for backfill of trenches crossing roads and  pavements.

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