CMDRCP / CW2C PACKAGE CW2C KM 18+200 – KM 23+450 EXCAVATION 1/ PHUONG THANH - QUYET TIEN - ANH GIANG – THANG LOI JOINT VENTURE CMDRCP / CW2C PACKAGE CW2C KM 18+200 – KM 23+450 TABLE OF CONTENTS I COMMON EXCAVATION, UNSUITABLE EXCAVATION, BORROW EXCAVATION II STRUCTURAL EXCAVATION III BORROW MATERIAL IV MAIN EQUIPMENTS 2/ PHUONG THANH - QUYET TIEN - ANH GIANG – THANG LOI JOINT VENTURE CMDRCP / CW2C PACKAGE CW2C KM 18+200 – KM 23+450 I COMMON EXCAVATION PREPARATION WORK Prior to excavation all site clearing shall have been completed in accordance with the appropriate specification to the satisfaction of the Engineer Before the start of any excavation the Contractor shall carry out a topographical survey of the area and prepare and submit the cross section and profile drawings to the Engineer for his approval These drawings shall be used as a basis for the computation of the actual volume of excavated materials USE OF EXCAVATED MATERIAL All materials removed from the excavation, that are evaluated by the Engineer as “suitable”, shall be used in the formation of the road embankment, sub-grade, shoulders, slopes, bedding, surcharge and counterweights, backfill for structures, topsoiling or for other purposes shown on the Drawings or as approved by the Engineer All excavations shall be finished to reasonably smooth and uniform surfaces Excavation operations shall be conducted so that material outside the limits of slopes will not be disturbed REMOVAL OF UNSUITABLE MATERIAL No materials shall be classified as unsuitable and remove from site without quantification by the Contractor and approval by the Engineer When material below sub-grade level in cut or below embankment foundation level not in areas of soft soil treatment is found to be unsuitable and the Engineer confirms it is to be removed, the soil remaining after the removal of the unsuitable material shall be compacted where practical to a depth of 20 cm and a density of 90 percent of the maximum dry density determined in accordance with AASHTO T99 Payment for such compaction shall be deemed included in the unit rate for excavation Unsuitable material shall be removed and disposed to disposal areas provided by the Contractor and subject to the approval of the Engineer The Contractor shall comply with all local environmental regulations when disposing of unsuitable material and shall include in his Environmental Management Plan all relevant details for the hauling and disposal of unsuitable materials DIMENSIONAL TOLERANCES Finished grades, alignment and formations after excavation shall not vary from those detailed in the drawings by more than 20 mm at any point All exposed finished excavated surfaces shall be properly graded and uniform, and shall have sufficient slope to ensure that they are free draining and free from ponding during rainfall II STRUCTURAL EXCAVATION GENERAL 3/ PHUONG THANH - QUYET TIEN - ANH GIANG – THANG LOI JOINT VENTURE CMDRCP / CW2C PACKAGE CW2C KM 18+200 – KM 23+450 Structural Excavation consists of the excavation for foundations to bridges, culverts, sub-drains and other structures, excluding specific details which may be contained in other specifications, as shown on the Drawings subject to the approval of the Engineer All material from structural excavation, so far as it considered suitable and subject to the approval of the Engineer, shall be utilized for backfill or embankment construction, or shall be removed from the Site if surplus to requirements All materials surplus to requirements shall be classified “Excavation of unsuitable material” in accordance with the requirements of item 2(c) of specification 03100 “Common Excavation” subject to the approval of the Engineer Structural Excavation shall include all necessary materials and equipment for keeping the excavation free of surface run-of and groundwater This Specification includes supplying, placing and compacting granular back-fill adjacent to structures in the areas indicated on the drawings subject to the approval of the Engineer This Specification includes the supply and placing of approved foundation fill material to replace unsuitable material encountered below the foundation level of structures Structural excavation shall include all necessary diversion of live streams, bailing, pumping, draining, sheeting, bracing, necessary construction of cribs and coferdams, and supply of materials required and subsequent removal of cribs, coferdams and remaining unsuitable material and placing of all necessary backfill EXCAVATION Prior to starting excavation operations in any area, the Contractor shall : ensure that all necessary Site Clearance and Demolition in that area has been approved by the Engineer ensure that all cross-sectional elevations and measurements have been taken of the undisturbed ground and submitted to the Engineer for his approval take steps on his own initiative to regulate the natural drainage of the surface water in the area to prevent flooding of excavations Excavations for structures or structural footings shall be of sufficient size to permit the placing of foundations of the full width and length shown indicated on the drawings The sides of excavations shall be adequately supported at all times The elevations of the bottoms of footings as shown on the Drawings shall be considered as approximate only and the Engineer may order, in writing, such changes in dimensions or elevations of footings as may be deemed necessary to secure a satisfactory foundation Boulders, logs, and any other unsuitable materials encountered in excavation shall not be used for back-filling purposes and shall be disposed of 4/ PHUONG THANH - QUYET TIEN - ANH GIANG – THANG LOI JOINT VENTURE CMDRCP / CW2C PACKAGE CW2C KM 18+200 – KM 23+450 After each excavation has been completed the Contractor shall submit the foundation to the Engineer for his approval No foundation or bedding material shall be placed until such approval has been given All rock or other hard material encountered in foundations shall be cleaned of all loose material and cut to a firm surface, either level, stepped or serrated, and all seams or crevices shall be cleaned out and grouted, all subject to the approval of the Engineer Where the foundation is to rest on material other than rock, excavation to the final level shall not be carried out until just before the foundation is to be placed Where the foundation material is soft or otherwise unsuitable, the Contractor shall remove the unsuitable material and replace it with granular backfill to the approval of the Engineer The granular fill shall be placed and properly compacted in layers not exceeding 15cm up to the foundation elevation However where the foundation material has been rendered unsuitable for reasons attributable to the Contractor he may replace the unsuitable material with granular material as described above or suspend works on the foundation until such time as the material becomes suitable Either solution shall be at the Contractor’s expense without revision to the contract period Where foundation piles are used the excavation of pile driving pits shall be completed before pile driving begins and any blinding stone required shall be placed after piles have been driven Where it is not possible to drive piles after excavation, piles shall be driven from the natural ground level subject to the approval of the Engineer In such case surplus pile lengths will not be measured for payment After both the excavation and the driving have been completed, all loose and displaced material shall be removed to leave a smooth, solid bed on which to place the foundation BACKFILLING On completion of the structure, excavated areas shall be back-filled with approved material to the level of the finished ground surface SOIL BACKFILLING Back-fill shall be placed in layers not exceeding 15 cm Initially and for any change in soil type, the Maximum Dry Density (MDD) shall be established in accordance with AASHTO T99 from at least three soil samples Compaction, based on at least one test per backfill layer, shall be 95% of the MDD so established Compaction method and equipment shall be suitable for use with the backfill material GRANULAR BACKFILLING Granular backfilling required for specific structures or other locations detailed in the drawings or as required by the Engineer shall be placed in layers not exceeding 15 cm and compacted to 95% (for K95) or 98% (for K98) of the maximum dry density determined according to AASHTO T99, as indicated on the Drawings The material shall be well-graded crushed or uncrushed gravel, stone, rock-fill or natural sand or a well-mixed combination of any of these Grading requirements for Granular Backfill shall be as follows: 5/ PHUONG THANH - QUYET TIEN - ANH GIANG – THANG LOI JOINT VENTURE CMDRCP / CW2C PACKAGE CW2C KM 18+200 – KM 23+450 Maximum size Passing 4.75 mm sieve cm 25% to 90% Passing 0.075 mm sieve 0% to 10% Liquid limit TCVN4197-95 30% max BLINDING STONE Blinding stone for use in foundations for structures as shown on the Drawings or as required by the Engineer shall be provided as detailed below Blinding stone shall be approved cobble-stone or crushed rock of the maximum size compatible with the thickness of the layer shown on the drawings subject to the approval of the Engineer The final surface shall be thoroughly compacted to the satisfaction of the Engineer using a mechanical rammer or vibrating roller III BORROW MATERIAL All suitable materials provided from borrow sources shall be used and placed to the grades, cross sections and other requirements indicated on the drawings subject to the approval of the Engineer During the operation of the borrow pit the Contractor shall ensure the pit remains in a safe properly drained condition The drainage shall be kept functioning and in as good condition as practicable and the sides and ends of borrow pits shall be maintained at the slopes included in the Contractor’s submission Where a borrow pit includes materials of distinctive types, excavation shall be carried out in a manner that ensures each type remains separate and that no mixing occurs Excavation shall also be carried out in such a way that excavated surfaces are free draining and that the as dug moisture content of borrow material remains unafected During excavation of the borrow pit temporary drainage shall be provided and maintained in order to prevent excessive surface run of and the erosion and possible sliding of materials onto adjacent properties or public roads Temporary drainage shall be directed into the existing local drainage system subject to suitable measures being taken to prevent silting or flooding from such existing drainage All hauling trucks and other construction plant leaving the borrow area or the area of placement on the site shall have wheels, wheel arches and other dirty sections washed before entering onto public roads Trucks used for hauling borrow materials shall not be overloaded Trucks used for hauling borrow materials shall be covered with canvas to prevent materials from being blown or falling of the truck The Contractor shall ensure that all operations related to the excavation and provision of materials from borrow pits comply with his approved Health and Safety plan, his approved Environmental Management plan and his approved Traffic Management plans The Contractor shall not obtain borrow material from locations other than the borrow areas approved by the Engineer for the Project 6/ PHUONG THANH - QUYET TIEN - ANH GIANG – THANG LOI JOINT VENTURE CMDRCP / CW2C PACKAGE CW2C KM 18+200 – KM 23+450 IV Main Equipments: Main equipments include: Equipments Units Quantity Bulldozer ≥ 110 HP nos 02 Front Loader ≥2,4m3 nos 02 Excavator 1,25m3 Nos Vibrating Roller 25ton nos Steel Wheel Roller 6– 12 ton nos Tired Roller nos Dump Truck ≥10 tons nos Laboratory Lab 7/ PHUONG THANH - QUYET TIEN - ANH GIANG – THANG LOI JOINT VENTURE ... PACKAGE CW2C KM 18+200 – KM 23+450 TABLE OF CONTENTS I COMMON EXCAVATION, UNSUITABLE EXCAVATION, BORROW EXCAVATION II STRUCTURAL EXCAVATION III BORROW MATERIAL IV MAIN EQUIPMENTS 2/ PHUONG THANH... STRUCTURAL EXCAVATION GENERAL 3/ PHUONG THANH - QUYET TIEN - ANH GIANG – THANG LOI JOINT VENTURE CMDRCP / CW2C PACKAGE CW2C KM 18+200 – KM 23+450 Structural Excavation consists of the excavation. .. classified ? ?Excavation of unsuitable material” in accordance with the requirements of item 2(c) of specification 03100 “Common Excavation? ?? subject to the approval of the Engineer Structural Excavation