METHOD STATEMENT FOR CW PIPE LINE CIVIL WORK

The purpose of this method is to describe the methodology involved in construction work for the CW Pipe line item and to detail out the steps to be taken in order to meet the technical requirements of VP1 BOT Thermal Power Plant

Comment Response Sheet (CRS) Project Title Van Phong BOT Thermal Power Plant Project Document Title METHOD STATEMENT FOR CW PIPE LINE CIVIL WORK Document Type For Approval Document No VP1-0-L4-C-UPF-10051 Returned Status NA Prepared by CRS No VP1-0-L4-C-UPF-10051-B-CRS CRS Issued Date 1/06/2020 Engineer Construction Review Date Status O/C * Remarks 15/05/2020 O 1/06/2020 C 15/05/2020 O 1/06/2020 C 15/05/2020 O 1/06/2020 C No Section/ Page Owner’s Comment Response to Comment 15/05/2020 TCVN 4447:2012 shall be referenced DHI has been updated Lot 1/06/2020 Closed 15/05/2020 - Capacity of machine should be stated - Pump for de-watering system shall be mobilized DHI has been updated 1/06/2020 Closed However, further comment about the capacity of pump is shown on page 3 15/05/2020 QC will participate in which step of this sequence for inspection? By that, Lot4 can establish a proper ITP QC shall be follow ITP of General Excavation & backfilling and General concrete work 1/06/2020 Closed Page of Comment Response Sheet (CRS) 15/05/2020 In case the worker will work at the bottom of excavation (pipe adjusting, welding, compaction ) the width shall be 700 for safety purpose, please refer to TCVN 4447:2012 1/06/2020 OPEN Applied standard shall be complied properly 15/05/2020 De-watering system shall be mention and reflect on section/layout At the design stage, The excavation section had been reviewed by Lot3 there is no issue about working space for Civil & Mechanical work 15/05/2020 O 1/06/2020 Closed O 15/05/2020 O 1/06/2020 C 15/05/2020 O 1/06/2020 C DHI revised as following comment & TCVN DHI has been updated 1/06/2020 Closed 6 15/05/2020 Specify the distance between the barricade and dike to the edge of the excavation The slope is very steep and the excavation is almost 6m deep A surcharge too close to the edge could lead to failure The dike also needs to be at a sufficient distance so that any minor local slope damage does not compromise the dike and lead to additional erosion damage The distance between the barricade and dike to the edge of the excavation is 2m DHI revised 1/06/2020 Closed Page of Comment Response Sheet (CRS) 15/05/2020 - With a deep excavation, any slope protection will be provide? slope stability check for 1:0.5 will be provided? - To insert the reference soil boring log to cross section of each zone or different soil condition 1/06/2020 OPEN - How to evaluate it is enough ratio for slope? CW pipeline is very long and soil condition change along Zone 2,3,4,5,6 Mean each zone may have a different typical section - To insert the reference soil boring log to cross of each zone or diff soil condition 14 15/05/2020 Present a typical access way and its arrangement 1:0.5 is enough ratio for temporary slope in consideration of ground condition at site 15/05/2020 O 1/06/2020 O Closed 15/05/2020 O 1/06/2020 C 15/05/2020 O 1/06/2020 C DHI added the Soil Investigation Report to reference list Slope stability for 1:0.5 had been checked as attachment2 The result is safe if there is any concern of soil condition during excavation time, DHI can make more slope, maximum 1:1 DHI has been updated 1/06/2020 Closed 17 15/05/2020 Excavation pit for welding work of CW pipe shall be mentioned? Is there any interface with Lot3? The excavation section had been reviewed by Lot3 There is no issue about working space." Mechanical work and the related will be fulfilled by Lot3 1/06/2020 Noted And will review in the method statement of pipe erection from Lot3 Page of Comment Response Sheet (CRS) 10 22 15/05/2020 It is totally unacceptable, this task contain a lot of potential critical hazards Moreover, risk assessment is a kind of anticipated document and preparing based on each kind of method statement EPC to prepare risk assessment for this task and pertaining to this method statement as it is integral part for the submission and site implementation DHI has been updated 15/05/2020 1/06/2020 O OPEN O Please refer to section 8.1 for detail comment 1/06/2020 OPEN Please refer to section 8.1 for detail comment Page of Comment Response Sheet (CRS) 11 Cover 1/06/2020 (1) Pls update the underground water level into the drawing sections (2) Item 6.2- Sand bedding: Noted excavated soil is not suitable for all Pls re-check and confirm AND compaction required layer by layer should be K95 1/06/2020 O 1/06/2020 Closed O (1)UG water level in Soil Investigation Report is meaningless for now cause the site condition has been changed by site development work.(some UG water level in SI report is indicating EL.+10 or 9) So we cannot figure out exact UG water level before excavation Or we can assume UG water level EL.+0.07 same as BH-42 which the elevation had not been changed remarkably (2)The mention was mistake DHI deleted Sand bedding will be tested for 95% Backfilling will be fulfilled layer by layer with mentioned % in design drawing (3) (3) Show protection of steel pipe at anchor contact pipe perimeter Please ensure no pipe uplift at any cases during construction 12 1/06/2020 Pump capacity ~20m3/h? It is seem not okay with an area of 150m x 16m? DHI will use soft material (ex Sand in site) around manhole of CW pipe DHI had discussed with CTCI they will not block end of pipe during installation to prevent pipe floating In addition, DHI make dike around excavation area to block ground water flowing into excavated area (in case CTCI install sand bag at the end of pipe, the height must be checked to prevent effective buoyancy.) DHI revised pumps can cover the area for rain 100mm/hour Page of Comment Response Sheet (CRS) 1/06/2020 Please provide the identification and propose the countermeasure for step of sand bedding mentioned in this method statement Based on Doosan's risk assessment procedure the JSEAs for identified tasks be prepared in for steps identified through the risk assessment process as having a Residual Risk Number greater than Please supplement the missing JSEAs for the review and site implementation Additional Notes (if any) * O - Open, C – Closed 13 24 1.DHI has been updated 2.JSA is basically same except the capital “E” (environment).And the submitted JSA is covering environment too 1/06/2020 OPEN PleaseOrefer to section 8.1 for detail comment Page of AP APPROVED Approved AC APPROVED WITH COMMENT Contractor to revise the correction and resubmit NA NOT APPROVED Revise the correction and resubmit before proceeding RE REVIEWED Information acknowledged with no comment For Approval RC REVIEWED WITH COMMENT Information acknowledged with comments Note: Approval or comment does not relieve the Contractor of all obligations covered under contract Discipline: Civil 16 Jun 20 Date: C 5-Jun-2020 For Approval J.H CHOI K.S KIM D.H JEONG B 21-May-2020 For Approval J.H CHOI K.S KIM D.H JEONG A 08-May-2020 For Approval J.H CHOI K.S KIM D.H JEONG REV DATE DESCRIPTION Approved Checked Prepared OWNER VAN PHONG POWER COMPANY LIMITED PROJECT Van Phong BOT Thermal Power Plant Project Status □Approved □Approved with Comment □Not Approved □Reviewed OWNER’S ENGINEER Pöyry Switzerland Ltd EPC CONTRACTORS IHI–TESSC–CTCI–DHI CONSORTIUM PROJECT DOCUMENT No REV VP1-0-L4-C-UPF-10051 C DOCUMENT TITLE METHOD STATEMENT FOR CW PIPE LINE CIVIL WORK EPC EPC DOCUMENT No VP1-0-L4-C-UPF-10051 Doosan Heavy Industries and Construction Page | REV C VAN PHONG BOT THERMAL POWER PLANT PROJECT Table of Contents PREFACE - 2 REFERENCE .- 2.1 Applicable Code and Standard - 2.2 Drawing and Method Statement - - MANPOWER & EQUIPMENT - RESPONSIBILITIES AND ORGANIZATION - PROCEDURE AND SEQUENCE - CONSTRUCTION WORK - 6.1 Excavation - - 6.2 Sand bedding .- 17 - 6.3 Backfilling - 18 - 6.4 Concrete Encasement - 21 - INSPECTION AND TESTING - 22 ENVIRONMENT, HEALTH AND SAFETY (EHS) - 23 8.1 Risk Assessment - 23 8.2 Job Safety Analysis - 49 - ATTACHMENT……………………………………………………………………………- 49- - - | Page VAN PHONG BOT THERMAL POWER PLANT PROJECT PREFACE The purpose of this method is to describe the methodology involved in construction work for the CW Pipe line item and to detail out the steps to be taken in order to meet the technical requirements of VP1 BOT Thermal Power Plant  Project Van Phong BOT Thermal Power Plant  Company/Owner Van Phong Power company limited(VPCL)  Contractor DHI  ITEM CW Pipe Line REFERENCE 2.1 Applicable Code and Standard • Part III-2 Exhibit B1 Tech Spec Section • Part III-2 Exhibit B1 Appendix G Civil/Structure Technical Guideline • TCVN 4447-2012 Earth works – Construction, check and acceptance 2.2 Drawing and Method Statement • VP1-0-L4-C-GEN-10007_ Rev C_ Method statement for General concrete work • VP1-0-L4-C-GEN-10008_ Rev B_ Method statement for Excavation and backfilling work • VP1-0-L4-C-UPF-12101_ Rev B_ CW Supply & Discharge Pipe Line Overall Plan Drawing • VP1-0-L4-C-UPF-12102_ Rev B_ CW Supply & Discharge Pipe Line Plan and Section Drawing • VP1-0-L4-C-GEN-00001_Rev H_ Soil Investigation Report MANPOWER & EQUIPMENT • Manpower mobilized for construction of the Boiler are listed as followings: No Position Quantity Site Manager 01 Site engineer 04 Safety supervisor 01 Surveyor 02 Excavator operator 03 Roller operator 03 Worker 60 - - | Page VAN PHONG BOT THERMAL POWER PLANT PROJECT • Equipment mobilized for construction of the Boiler are listed as followings: No C Equipment Unit Quantity Capacity Total station nos 02 - Auto level nos 02 - Dump truck nos 10 8-18m3 Excavator nos 03 0.7-1.5m3 Roller nos 02 14ton Rammer nos 02 0.7ton Plate compactor nos 02 Light nos 20 Electric Pump nos 15 400W 11HP120m3/h RESPONSIBILITIES and ORGANIZATION • It is overall responsibility of Site Manager to organize resources prior to perform construction activities as per project specification in compliance with the quality, schedule & safety requirements • EHS Manager will ensure in coordination with Site Engineer that all measure/construction taken shall be maintained till completion of job • It is the responsibility of Construction Manager/Site Engineer that construction activities are executed according to the relevant project specification in compliance with the quality, schedule & safety requirements • Contractor will ensure that all works are performed safely according to the attachment • The relevant contractor Supervisor will ensure that the work is carried out in accordance with this method statement and project specification • The QC Inspector will ensure that the work is executed according to the requirements of quality dossier are fulfilled - - | Page VAN PHONG BOT THERMAL POWER PLANT PROJECT [ Environment, Social & Health ] - Dust emissions into air - Generation of noise - Uncontrolled access - Theft - 44 - | P a g e [ ES&H ] - Effect on people health due to dust emission into air - Effect on people health due to excessive noise - Exposure of general public to the work areas rails/nets/bags), where possible, erected and inspected by competent persons 3- Where the above is not practical individual fall protection (harnesses/lanyards/inertia reels) shall be used 4- Only when none of the above is practicable ladders/step ladders shall be considered - Only competent people authorized to working at height - Only competent authorized persons allowed to erect any working at height equipment - Regular inspections of working at height equipment to be undertaken by competent persons - Segregation of area below using signage and barriers warning of restricted access - Emergency fall procedures implemented - PPE must be worn at all times - Practice 100% tie-off when working at height - Installation of canopy specially on the access way [ Environment, Social & Health ] - Control of dust emissions through regular water sprays - Control of noise through strict inspection of all equipment before entering to site and provision of acoustic barriers where noise exceeds the allowable limits - Establishing fence and security system to restrict the unauthorized entry to work site involved, a new risk assessment will be conducted and further control measures implemented to suit the operation RRN >6 for this activity therefore a Job Safety and Environmental Analysis (JSEA) shall be prepare and attached with PTW as if required VAN PHONG BOT THERMAL POWER PLANT PROJECT Site personnel, Subcontractor s & Others Concrete activity [ Safety ]- Contact with concrete materials entering the body, eyes through o exposed skin o Absorption o Inhalation- Slip, strip Falling during executing.- Long time working with big volume concrete pouring [ Safety ] - health - Cancel - Lung ache - fatigue [ Environment, Social & Health ] - Concrete waste disposal improperly [ ES&H ] -Environmental incident - Natural affect / absorb 15 [ Safety ] - Movement of concrete mixer, concrete pump vehicle must have planned Place area condition for the pump vehicle must be checked thought out before setting up Isolated vehicle stand / movement area Signalman / watcher be place to guide the reversing vehicle, mixer - Pump pipe holder must wear coverall clothes with face shield to avoid splash concrete to the body or eyes Other partner must wear proper PPE with a lessen skin exposing purpose - Safety boots for concrete activity - Role type working Set proper working shift (routines) for each team to prevent fatigue due to long time working - Wash hand, clean face and mouth before drink or eating during break time- Light providing proper for night work Control measures will be regularly reviewed and monitored to assess their suitability and improvements made if required If any change is made to the working condition or operation i.e change in sequencing, new plant/equipment or new workers involved, a new risk assessment will be conducted and further control measures implemented to suit the operation [ Environment, Social & Health ] - concrete waste must be disposal at designated area Curing concrete / remove formwork/ dismantle scaffolding structure / housekeeping Housekeepin g Site personnel, Subcontractor s & Others - 45 - | P a g e [ Safety ] - Slips, trips and falls - Falling of materials and objects - Fire [ Safety ] - Fatality - Personal injury - First aid injuries 12 [ Safety ] - Clear unobstructed walkways - Clear and safe access and egress - Effective material storage in segregated areas - Regular monitoring of work areas - Unwanted materials remove from site immediately 2 Control measures will be regularly reviewed and monitored to assess their suitability and improvements made if required If any change is made to the working condition or operation i.e change in sequencing, new VAN PHONG BOT THERMAL POWER PLANT PROJECT [ Environment, Social & Health ] - Generation of diseases - Contamination of land [ Safety ] - Contact with hazardous materials entering the body through o Ingestion o Absorption o Inhalation - Acute and chronic effects Use of chemical materials for formwork recycle [ ES&H ] - Effect on people health - Land contamination - Water pollution - Social conflicts in shape of community complaints [ Safety ] - Serious personnel injury or fatality Site personnel, Subcontractor s & Others [ Environment, Social & Health ] - Generation of fumes - Accidental release - 46 - | P a g e [ ES&H ] - Irritant; Dermatitis and Bronchitis - Corrosive; Burning of living tissue - Toxic; Damage to kidneys, liver 15 [ Environment, Social & Health ] - Effective waste management (waste bins provided around site and skips segregated, with waste disposed of by an approved licensed contractor) - Monitoring of waste collection contractor and ensuring the dumping in licensed area plant/equipment or new workers involved, a new risk assessment will be conducted and further control measures implemented to suit the operation [ Safety ] - Materials to be stored in a lockable container marked as ‘hazardous materials’ - Only competent people to have authorization to materials - Correct PPE to be worn at all times - MSDS control measures and guidance to be followed - CASH register and issue sheets to be recorded and maintained - Health and medical surveillance to be undertaken - Never use drinking water bottle as secondary containment for chemicals - Must provide proper secondary containment dedicated for chemicals [ Environment, Social & Health ] - Use and storage shall be according to the instructions of manufacturer as mentioned in MSDS Control measures will be regularly reviewed and monitored to assess their suitability and improvements made if required If any change is made to the working condition or operation i.e change in sequencing, new plant/equipment or new workers involved, a new risk assessment will be conducted and further control measures implemented to suit the operation VAN PHONG BOT THERMAL POWER PLANT PROJECT and heart - Carcinogenic; Promotion of abnormal body cells becoming cancers - Mutagenic; Damage to genetic material passed on for future generations - Air pollution - Soil contamination - Water pollution Prepared By: Signature: Approved By : Signature : Position Position: : Risk Factor Number (RFN) 1-2 Trivial/Acceptabl e Date : 05 June 2020 Frequency Severity 1: Unlikely/Imp robable 1: Negligible 2: Remote 2: Slight - Tolerable 3-5: Tolerable 3: Quite Possible/Occ asional 3: Moderate 6-9 Moderate/Acceptable with review 6-9: Moderate/Acceptable with Review - 47 - | P a g e Residual Risk Number (RRN) 1-2: Trivial/Acceptable * Prepare Job Safety Analysis when RRN is > L1 - Likelihood as is L2 - Likelihood with mitigating controls in place S1 - Severity as is VAN PHONG BOT THERMAL POWER PLANT PROJECT 4: Likely/Proba ble 5: Very Likely/Frequ ent - 48 - | P a g e 4: Critical/High 10 -15 Substantial 10-15: Substantial 5: Catastrophic/Very High 16 - 25 Intolerable/Unacc eptable 16-25: Intolerable/Unacceptable S2 - Severity with mitigating controls in place VAN PHONG BOT THERMAL POWER PLANT PROJECT 8.2 Job Safety Analysis List of All Job Steps List of All Known Hazards How to Eliminate Hazards A Survey Works A.1 Instrument falling down and hit a workmen A.1 Area where the instrument is to be must be well compacted A.2 Instrument dropping ground by accident A.2 Focus and concentrate all the time during work execution B Working Operation During Night Time to A.3 Stuck into the muddy area A.3 Always beware and walk on designated access A.4 Pegs splatters into the eyes A.4 Always wear safety PPE B.1 Working operation of the equipment may cause injury to personnel due to poor visibility of the area B.1a Must provide sufficient lightings on the entire working area B.1b All equipment must be fitted with appropriate safety device and ensure all lights are operational not obscured by dirt and mud B.1c Supervisor and safety personnel shall always be present for the necessary working B.1d All workers must be wearing visible PPE B.2 Generator (Diesel) equipment oil leakage during operation B.2a Daily check of the equipment prior to start of work B.2b Regular check &monitoring of the equipment prior to use B.2c Provide sundry containment protection under the equipment to prevent contamination of soil by oil spillage B.3 Oil/chemical storage B.3 Diesel/chemical shall be scored in sundry containment & MSDS requirement shall be communicated with all concerned B.2b Regular check &monitoring of the equipment prior to use B.2c Provide sundry containment protection under the equipment to prevent contamination of soil by oil spillage Excavation of Soil, Rock and Trenching C.1 Slip and trip of workers C.1 Secure confirmation by EHS manager regarding assigned engineers and workers C.2 Fall of workers and equipment C.2 Excavation plan and excavation work checklist must be available at the work site C.3 Cave-in of excavation walls C.3a Assign licensed and experienced operator C.3b Excavation site must be cordoned with safety warning tapes and/or hard barricades painted with red & white whichever is applicable including provision of sufficient lightings and blinker lights during nighttime - 49 - | P a g e VAN PHONG BOT THERMAL POWER PLANT PROJECT C.3c Install adequate safety signs such as excavation in-progress, keep-out deep excavation, etc C.3e Assign experienced and trained personnel /workers C.3f Provide spoil area away at least meters from the edge of the excavation to avoid cave-in or collapse in case excavated materials will not be hauled or disposed at once C.3g Provide sufficient shoring system, sloping of ground or other equivalent means such as sheeting, cross bracings, trench shield or box and jacks, benching, etc whichever is applicable C.3h Prohibit movement of vehicles and equipment near the edge of the excavation that may result to side wall excavation cave in or collapse due to severe ground movement D Backfilling Works D.1 Slip and trip of workers D1 Implement method statement / procedures on safe backfilling works D.2 Fall of workers and tools /equipment D.2a Strict supervision during backfilling works D.2b Wearing of the required PPE D.2c Assign licensed and experienced operator D.2d Assign experienced and trained personnel /workers E Trenches E Falling from height and cave-in E.1 Earth excavated to be stored meters away from excavation area E.2 Vehicle to be kept in meters from edge of excavation E.3 Experienced and trained workers E.4 Essential PPE in use F Environmental Conditions During Excavation Works F Extreme environmental condition such as high temperature & humidity and strong wind F.1 Implement safety procedures &guidelines on heat stress F.2 Inspect excavation and adjacent areas for possible hazardous atmosphere and any other condition that may present a hazard F.3 Suspend / stop all operations during extreme temperature & humidity and high wind G Dewatering - 50 - | P a g e G.1 Pump equipment (Diesel Engine) oil leakage during operation G.1a Daily check of the equipment prior to start of work VAN PHONG BOT THERMAL POWER PLANT PROJECT G.1b Regular monitoring of the equipment sin order to control and prevent oil leakage and other engine trouble G.1c Provide sundry containment protection under the equipment to prevent contamination of soil by oil spillage G.2 Electric shock due to without ground external box on pump station and circuit breakers G.2a Provide adequate ground and circuit breakers G.2b Designate electrician/operator for the pump equipment H Disposal of Excavated/Excess Materials H Collision between equipment H.1 Prepare access for the equipment to be provided I Dust Control I Vehicle/equipment transporting of excavated soil to the disposal I.1 Spraying of water on the road as required to ensure no dust flying - 51 - | P a g e VAN PHONG BOT THERMAL POWER PLANT PROJECT ATTACHMENT1: CALCULATION SHEET FOR THE ARCHIMEDES PRESSURE AND CHECKING THE REBAR FOR RESISTING ARCHIMEDES PRESSURE Input Data: CWpipe D3600 OD (m) Unit Weight (T/m) Encasement Length (m) Concrete Unit Weight (T/m3) 3.696 1.72569 2.5 Calculation: W = Pipe Unit weight * Length of Encasement = 13.81 (T) PHASE 1:CAST CONCRETE TO 580mm height Self-weigh of mass concrete Wmass= B*D*H*L= B= D= H= L= Wmass= 55.9167456 T W=Wpipe+Wmass= 4.8 2.5 0.5824661 m T/m3 m m 69.72 T PHASE 2:CAST CONCRETE TO +2.3M HEIGHT Fb0.08=Vs.D Vs (m3) Vs (m3)= D(T/m3) Fb1.8=Vs.D Vs (m3) Vs (m3)= D(T/m3) 13.8 (T) =R²/2*(απ/180-sinα)*L : Volume of CW pipe inside concrete If H= 0.082461 (m) α=2acrcos(1-h/R)= 34 o 5.526 2.5 : Density of concrete 75.1 (T) =R²/2*(απ/180-sinα)*L : Volume of CW pipe inside concrete If H= 1.8 (m) α=2acrcos(1-h/R)= 177 o 30.047 2.5 : Density of concrete Conclusion: If calculation with pipe length equal encasement length, L=8m W= 69.72 (T) Checking: if W>Fb: OK, conversely: Recheck Fb=Fb1.8-Fb0.08 61.30 (T) OK - 52 - | P a g e VAN PHONG BOT THERMAL POWER PLANT PROJECT PHASE 3:CAST CONCRETE THE REST Fb=Vs.D Vs (m3) 85.4 (T) =R²/2*(απ/180-sinα)*L : Volume of CW pipe inside concrete If H= 1.848 (m) α=360-α1.2M Vs (m3)= D(T/m3) 183 34.149 2.5 : Density of concrete Self-weigh of mass concrete Wmass= B*D*H*L-0.5*3.14*R^2*D*L= B= 4.8 D= 2.5 H= 2.3 L= Wmass= 113.5657344 T W=Wpipe+Wmass= o m T/m3 m m 127.37 T Conclusion: If calculation with pipe length equal encasement length, L=8m W= 127.37 (T) Fb= 85.37 (T) Checking: if W>Fb: OK, conversely: Recheck OK Checking the rebar as anchor Capacity of tension for D16 T16=fy*F16 With rebar CB400V fy= 400 N/mm2 Area of section F16= 201.0619 mm2 T16= 8.20 T The quantity of rebar= 1.1*Wmass/T16= With 1.1 is safety factor Space of rebar s=L/segment= Choose - 53 - | P a g e 16 nos 533.3333 mm 500 mm VAN PHONG BOT THERMAL POWER PLANT PROJECT #ATTACHMENT2: Stability - 54 - | P a g e Check for Excavation Slope for CW Pipe near CW PS Attachment #2_Stability Check for Excavation Slope of CW Pipe in CW P/S Area GENERAL This calculation is to check the slope stability for excavated slope Factor of satety of slope in excavation surface is examined by Bishop and Janbu method using SLOPE/W software ANALYSIS METHOD For the stability check on the excavation slope, limit equilibrium analysis was performed using the Slope/w program The Bishop and Janbu method whose reliability was verified in circular & non-circular failure was applied Limit equilibrium condition Method Description Failure type Fellenius Direction of the resultant interslice force is paralled to the base of the slice The balance of vertical force for the base of the slice was considered Circular O X X Bishop Interslice shear force is zero The balance of vertical force the base of the slice was considered Circular O O X Janbu Location of interslice normal force is defined by an assumed line of thrust Circular & NonCircular O O O Moment Vertical force Horizontal force EXCAVATION PLAN Excavation and sections for stability check are: No Area CW Pipe nerar CW Pump Station Area Excavation Depth Ground Level EL.+0.5 EL.+5.6 Page SOIL PROPERTY Soil property for soil layer(BH-42) is refered from Soil investigation report (Ref VP1-0-L4-CGEN-00001) Layer Unit Weight (kN/m3) Cohesion (kPa) Friction angle (degree) Elevation (m) Sandy Clay (Layer 4) 19.4 23.1 14 EL+5.6 ~ +2.58 Clay (Layer 5) 18.3 28.9 13 EL+2.58 ~ -10.52 SAFETY FACTORS FOR SOLPE STABILITY The required safety factors for stability performance is summarized in following Condition Safety factor Remarks Temporary 1.25 NAVFAC-DM 7.1 GROUND WATER LEVEL Tide level in Excavation area for the design is as following - Ground Water Level : EL+0.07m (Ref VP1-0-L4-C-GEN-00001) SECTION FOR SLOPE STABILITY ANALYSIS CW Intake Pump Station Page ANALYSIS FOR SLOPE STABILITY Model Analysis Result Bishop Metod Janbu Method 1.535 > 1.25 ∴ OK 1.525 > 1.25 ∴ OK * 13kN/m2 of surcharge load was considered on the ground level Page RESULT OF SLOPE STABILITY ANALYSIS Section CW Pipe nerar CW Pump Station Area Temporary Condition (Min Safety Factor) Bishop Janbu 1.535 1.525 Evaluation OK Analysis result confirmed that the planned slope shown in below drawings have enough stability during temporary construction condition Relevant Drawing VP1-0-L4-C-UPF-12102_C_CW SUPPLY & DISCHARGE PIPELINE PLAN & SECTION DRAWING Page