3.1 Introduction..................................................................................................42

3.2 PRB Engineering Design Methodology....................................................43

3.2.1 Selection of Reactive Material ........................................................43

3.2.1.1 Geochemistry of GW ........................................................ 45

3.2.1.2 Reaction Kinetics............................................................... 45

3.2.2 PRB Engineering Design ................................................................ 47

3.2.2.1 Hydrogeological Data for PRB Design........................... 47

3.2.2.2 Sizing the Reactive Material Wall................................... 48

3.2.3 Type and Configuration of Barrier................................................ 49

3.2.3.1 Continuous PRBs............................................................... 50

3.2.3.2 Funnel-and-Gate PRBs ..................................................... 50

3.2.3.3 Reactive Vessels................................................................. 51

3.2.3.4 Caissons PRBs.................................................................... 51

3.2.4 Performance Monitoring................................................................. 52

3.3 PRB Construction Techniques ................................................................... 53

3.3.1 Excavation Techniques ....................................................................54

3.3.1.1 Biopolymer Trenching......................................................54

3.3.1.2 Continuous Trenching......................................................54

3.3.1.3 Unsupported and Supported Excavation ...................... 55

3.3.1.4 Sheet Piling ........................................................................ 55

3.3.1.5 Slurry Wall ......................................................................... 56

3.3.2 Injection Techniques........................................................................ 57

3.3.2.1 Hydraulic Fracturing........................................................ 57

3.3.2.2 Jetting.................................................................................. 58

3.3.2.3 Soil Mixing......................................................................... 58

3.4 Conclusion .................................................................................................... 59

References............................................................................................................... 60

3
Choosing the Best Design and Construction

Technologies for Permeable Reactive Barriers

Dawit N. Bekele, Ravi Naidu, Volker Birke,
and Sreenivasulu Chadalavada
CONTENTS
41