Innovative Geotechnical Solutions

Transcription

1 Innovative Geotechnical Solutions Innovative Applications of Geosystems in the Hydrocarbon Industry Shahrokh Bagli Chief Technology Officer 7 th February,

2 The Geosystems 2

3 Areas of Applications Paved & Unpaved Roads Access, Haul, Emergency & Service Roads Road Shoulders Industrial Flooring Container Yard, Logistic Terminals and Laydown Sites Ground Improvement Systems Precast Arch Systems Bridges Railways Tunnels Cut-and-Cover Tunnels culverts Underpasses and Grade Separators Effective Alternative to Structural Walls Slope stabilisation Erosion Control Reinforced Soil Systems Slope Protection Systems Reservoir Lining Landfill Closure Embankment Slopes 3

4 Basic Geosystems StrataWeb Geocells StrataGrid Geogrid BEBO Precast Arch System 4

5 StrataWeb Geocells 5

6 The Geocell System Lightweight but strong three dimensional honeycomb-like cellular confinement system Honeycomb structure is one of the strongest structural systems Fabricated from ultrasonically-welded HDPE strips that are expandable at site to form the honeycomb structure Confinement of non-cohesive material within provides rigidity to geocell system Confinement greatly reduces the lateral movement of confined soil particles Perforated for porewater pressure relief Textured within for better soil-cell wall interaction 6

7 History of Geocells Invented by the US Army Corps of Engineers in 1970s Used during the Vietnam and Gulf Wars for heavy equipment movement over soft / loose ground; marshes and desert sand Used for civilian applications in the 1980s 7

8 StrataWeb Geocells: Load Support Applications 8

9 Principle of Geocells for Load Bearing Geocells filled with cohesionless material form rigid mats capable of distributing imposed loads over larger area If q₀ is the vertical pressure Lateral stresses generated equals k₀(q₀+p)/2 in loaded cells Lateral stresses are generated in congruent cells as reaction This increases shear strength of the confined soil WHICH CREATES A STIFF MATTRESS WHICH CONTRIBUTES TO DISTRIBUTING THE LOAD OVER A LARGER AREA 9

10 Typical Road Section BC 50mm DBM 170mm WMM 250mm GSB 300mm BC 50mm DBM 140mm WMM 100mm GSB/quarryrun50mm StrataWeb 150mm depth with GSB infill Savings in soil excavation and quantity Conventional section (CBR 5%, 150 MSA) StrataWeb section Advantages of Geocells: Reduces overall crust thickness by reducing WMM, DBM and GSB layers Reduces initial cost by 4-12% besides providing maintenance savings 10

11 Technical aspects - Load Support Systems Poor load-bearing soils pose significant problems for both paved and unpaved surfaces Unpaved roads in wet conditions and high axle loads are vulnerable to near-surface shear failure and rutting With geocells HDPE cell walls maintain shape and integrity of the structure, allowing heavy equivalent axle loads without lateral movement of infill material Cellular structure of the geocells distributes loads over a large, extended area, reducing stress to subgrade below Thickness of the overall pavement section and sub-base can be decreased with equivalent, if not greater structural integrity Facilitates use of lower quality aggregates and materials locally available, eliminating need to import better quality material 11

12 Applications Engineered Solution for: Roads - National & State Highways -Access / Service Roads -Port Roads - Haul roads, Paved / Unpaved roads to oil fields - Road Shoulders Railway ballast confinement and subgrade strengthening Slope Erosion Protection Reservoir Lining Embankment Ground Improvement Tank Farm Pads, Pipe Supports Terminal Depots Tanker loading / unloading Terminals Terminal Lay-down Sites Industrial Flooring 12

13 Application - Load Support Roads - Paved & Unpaved Ports & Container Yards Industrial Flooring Basal Improvement 13

14 Benefits Load Support Applications Strength:By spreading the imposed load, it improves the load carrying capacity of a weak base Cost-effective Solutions:Use of locally available and cheaper material in decreased quantities reduces raw material costs and consumption; allows a thinner road section hence lesser excavation Logistics: Easy to transport owing to its flat and collapsible structure Rapid Installation:Proven to be an all weather installation system with minimal requirement of specialized equipment and labour Maintenance:Reduces the frequency of maintenance and effort required in each maintenance cycle Environmental Friendly:Smaller carbon footprint due to minimal logistics and resource requirements 14

15 StrataWeb Geocells: Slope Protection Applications 15

16 Slope Erosion Protection Geocellsprovided along the slope surface to prevent erosion of the slope surface due to surface run-off Geocells may be filled with plain cement concrete (pcc) with soils with fertiliser and seeds 16

17 Application- Slope Protection and Lining Landfill Lining Reservoir Lining Slope Protection Canal Lining 17

18 Application- Slope Protection and Lining Landfill Lining Reservoir Lining Slope Protection Canal Lining 18

19 Benefits - Slope Protection System Steep Slopes: Can be used to line slopes as steep as up to 1V:1H Logistics: Sections are transported in collapsed format and concrete is poured through RMC mixers or placer booms Customised: Can be cut and placed as per the contour of slope Infilling: Can be filled with concrete / gravel / soil supporting vegetation Rapid installation: Can easily cover 400m 2 per day and no special equipment required during execution Liner Protection: Puncturing of underlying geomembrane can be avoided Protection Thickness: Requires less thickness; up to 80mm; hence there is savings in terms of concrete Economical: Requires negligible maintenance as compared to conventional solutions Design Life: Over 100 years 19

20 BEBO Precast Concrete Arch System 20

21 Precast Concrete Arch: History Old Principle (since 800BC) using modern Technology Patented Swiss precast arch technology for bridges, culverts and underground structures developed in 1965 Over 1000 structures the world over since 47 years and spans up to 30m Applications Small to middle span bridges (up to 30m and more) Cut-and-cover tunnels (road, rail) Culverts and underground structures (drainage channels, storage, etc.) 21

22 Precast Concrete Arch: Technology Fabrication and Design conform to the Design Standards of various Codes Soil Reinforced Concrete Structure Interaction Systems Thickness adequate to take up stresses due to applied loads Thickness is small enough such that arch flexing develops resistance between at rest and passive from the soil behind 22

23 Precast Concrete Arch: Technology Arch Elements Designed for: Transportation Handling and Erection Backfill Load Cases In-Service Loads with overfill ranging from 0.5m 5m State-of-the-art Finite Element Analysis Software 2.44 m (8') 1.5 ft Overfill 3.05 m (10') 2.44 m (8') 1.83 m (6') 0.61 m (2') 1.22 m (4') 1.83 m (6') 23

24 Precast Concrete Arch: Components Arches Spandrels Footings Wing Walls Arch Element Wing Wall Spandrel Wall Foundation 24

25 Precast Concrete Arch: BEBO Series The E-Series (Elliptic) Span Range from 3.7m to 25.6m Overfills from 0.5m to 5.0m 25

26 Precast Concrete Arch: BEBO Series The C-Series (Circular) Span Range from 9.1m to 16.5m Designed for high overfill applications 26

27 BEBO Casting and Installation 27

28 BEBO :NH-30 Skew IOCL Pipeline Crossing 28

29 BEBO : Benefits Economy: Concrete savings by virtue of a thinner section While weight of steel per unit concrete volume is high, there is overall savings due to thinner section Speed Installation of basic concrete segments within hours No restriction for construction machinery to traverse the structure once minimum overfill height is achieved Quality Safety through compliance with specifications and guidelines Longevity owing to earth overfill Much easier maintenance No approach slabs or bridge decks to deteriorate Environment friendly massive savings in sand, cement, steel 29

30 StrataGrid Geogrid 30

31 Geogrid: StrataGrid Manufactured under stringent quality controls using specialised High Tenacity (HT) Polyester Yarn HT yarn is made from PET polymer with: High molecular weight (>25,000 g/ mol) Low CEG number, less than 30 Low creep Has unique UV stabilised Polymer Modified Bituminous (PMB) Coating: Which provides excellent environmental, chemical and mechanical properties Its unique feature ensures minimum thermal exposureto PET fibre, hence preventing polymer degradationand enhancing performanceresults like low elongation 31

32 Concept of Soil Reinforcement A box is filled with aggregates Compaction of aggregates Collapse of aggregates after removal of confining walls Aggregates now take the load of an SUV Confinement walls rendered redundant Insertion of Geogrid at intervals with aggregate filling in layers 32

33 Components of a RS Structure Typical RS structure cross section 33

34 Applications Reinforced Soil Wall Block Faced RS Wall Panel Faced RS Wall 34

35 Applications Landfills Reinforced Steep Slope 35

36 Applications Rail Track Stabilization Road Subgrade Stabilization 36

37 Your partner in quality, safety, efficiency and growth Thank You 37