Seepage and Drainage

Water moving through soil controls many foundation and earthwork problems. This chapter starts with an introduction to permeability and seepage analysis, then covers how seepage is controlled with cut-offs and how drainage blankets and filters are designed.

It also covers wellpoint systems and deep wells for dewatering, linings for reservoirs and pollution control facilities, and erosion control. A final section describes the laboratory permeability tests used to measure the properties that the analysis depends on. The chapter matters for dams, levees, cofferdams, excavations, and retaining walls alike.

In this chapter

• Introduction to Permeabilitypage 360
  • Application of Permeability Data
  • Seepage Forces
• Seepage Analysispage 364
  • Flow Net
• Seepage Control by Cut-offpage 366
  • Sheet Piling
  • Grouted Cut-off
  • Impervious Soil Barriers
• Design of Drainage Blanket And Filterspage 373
  • Filters
  • Drainage Blanket
  • Intercepting Drains
  • Shallow Drains for Ponded Areas
  • Pipes for Drainage Blankets and Filters
• Wellpoint Systems and Deep Wellspage 382
  • Methods
  • Wellpoint Systems
  • Sumps
  • Electro-Osmosis
  • Pumping Wells
  • Relief Wells
• Linings for Reservoirs and Pollution Control Facilitiespage 387
  • Purpose
  • Types
  • Subdrainage
  • Investigation For Lining
• Erosion Controlpage 387
  • General
  • Investigation
  • Surface Erosion Control
  • Channel Linings
  • Sediment Control
  • Riprap Protection
• Laboratory Permeability Testspage 398
  • Equipment
  • Constant-Head Permeability Test with Permeameter Cylinder
  • Falling-Head Permeability Test with Permeameter Cylinder
  • Permeability Tests with Sampling Tubes
  • Permeability Test with Pressure Chamber
  • Permeability Tests with Back Pressure
  • Permeability Tests with Consolidometer
  • Possible Errors