Underground Infastructure and Deep Foundation Conference
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P R O V I D I N G E N G I N E E R E D S O L U T I O N S June 2, 2014
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ACTION INTERNATIONAL SERVICESCORE SERVICES
Groundwater Control (Dewatering) & Hydrogeological Investigation
Industrial Services & Equipment Rentals
Saudi ArabiaUnited Arab EmirateQatarOmanBahrain
DEWATERING CHALLENGES IN QATARHigh variation of Qatar geology & Hydraulics
Long procedure for permit
Lack of discharge facilities
Groundwater treatment & management
OVERVIEW OF QATAR GEOLOGY
QATAR GEOLOGY - AMC
Level (m, QNHD)
Reference: AMC-QDVC
HIGH VARIATION IN GEOLOGY/HYDRAULIC AMC AS CASE STUDY
150mSectionSection ASection BExcavation level (m QNHD)-20.675-11.485Horizontal Hydraulic conductivity (m/s)1.03E-44.61E-5Flow (m3/h) 10335
Section ASection B
PRESENT & PROSPECTIVE GROUND INVESTIGATIONCentered around Foundation with little or no dewatering consideration
Present Ground Investigation
Prospective Ground InvestigationDetailed Hydraulic test (vertical & horizontal Hydraulic conductivity)Groundwater physical & chemical analysisGeophysical test
APPROACH TO DEWATERING CHALLENGESDetailed Subsurface & Hydraulic AssessmentHistorical Information & Site ExperienceReview of soil investigation reportAnalytical modelling based on 1 & 2Numerical modelling (2D/3D) based on 1 & 2Insitu Test (Pumping Test & Slug Test)Recalibration of 3 & 4 based on 5.
APPROACH TO DEWATERING CHALLENGESStep 1:Visual Investigation/ Site visitHistorical Data/Dewatering Experience within locationSoil InvestigationReport
Numerical (2D/3D) & Analytical Model Step 2:
Pumping TestSlug Test
Insitu TestModel recalibration
3D MODEL FOR A METRO STATION IN QATAR
ADVANTAGES OF HYDRAULIC TEST PUMPING TEST
Estimate hydraulic parameters (vertical & horizontal hydraulic conductivity) which are important in designing cost effective dewatering system
It gives a wide range of aquifer properties on like Slug test and Percolation test which are location specific.
It gives good estimate of expected flow, pump requirement for dewatering works
It gives a better understanding of hydraulic behavior over a period of time
Analyses is more detailed with little uncertainty compared to other hydraulic test
GROUNDWATER MANAGEMENT PRACTICES
Sources of Water in QatarDesalination 48%
Fresh water from Aquifer 38%
Sewage water 14%Qatar is the second most water stressed in the world Water stress index 2011
Conservation PracticesOnsite treatment & Reuse
Onsite treatment & Discharge to sewer systemGroundwater recharge practices
Optimized groundwater design for dewatering by performing relevant hydraulic testSewer size due to discharge volumePermitExpected Treatment limit prior to discharge
GROUNDWATER DISCHARGE MANAGEMENTOnsite treatment & Reuse
Onsite treatment & Discharge to sewer systemGroundwater recharge practices
Optimized groundwater design for dewatering by performing relevant hydraulic testSewer size due to discharge volumePermitExpected Treatment limit prior to discharge
WHERE WE CREATE VALUESProject engagement
Understanding work program
Interpreting soil investigation report & geotechnical information for dewatering design
Recommendation of relevant Insitu hydraulic test based on project
Dedicated team Project Engineers & Hydrogeologist
Shared understanding of critical part & RiskSoil contaminationWater quality & Required treatmentPotential cavities/sinkholesExcavation type Open or Shored Flow Estimate & Discharge options
Tender Stage
WHERE WE CREATE VALUES
Sub. Contractor TenderUnderstanding work program
Recalibration of design/models and assumptions during the tender stage
Optimizing system to accommodate budget
Project ExecutionAdherence to standard practise
Daily system monitoring (Automated & Manual) and performance reporting againstLateral pressure (open excavation/shored system)Uplift pressure3. Dedicated Project & Site Engineers
WHERE WE CREATE VALUES
Tender Stage
Sub. Contractor Award
Contract Award
Sub. Contract Tender
Project ExecutionTeam continuity
Better program understanding
Good project management
Benefits
Thank You
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