The long-term performance of geocomposite sheet drains were monitored at three sites by measuring the effect of the drains on site groundwater hydrology during peak groundwater events. The study is on-going with a maximum record of 14 years at one site in the southern Sierra Nevada Range, CA.‍?Over a 3-year period, the drain at one site produced as much as 100 liters per minute with no rise in the water table just down gradient from the drain. The peak hydraulic gradient toward this drain consistently reaches 0.66 to 0.73 during major rainstorms and returns to a S2base levelS3 of 0.45 to 0.50 within 10 days after a storm peak.‍?At a second site, the drain flowed up to 15 liters per minute with no water table rise in a retaining wall fill down gradient from the drain. Performance of this drain was consistently favorable over a 14-year period with no deterioration. Limited data suggest that the drain discharge (liters per minute) is proportional to about 13 times the hydraulic gradient toward the drain.‍?At a third site, drain performance is limited by construction problems. A collapsed trench wall during drain placement caused an uneven drain slope toward the outlet. This is a common problem of trench drains at sites with a high water table. The problem could be greatly mitigated by returning to one of the pioneering geocomposite drain designs, the Eljen Drain, in which vertical sections of the drain are completely independent units that can be immediately dropped into a trench behind the excavator. Despite the construction problems, the drain is partially dewatering the road prism just down gradient, as seen by approximately 1.2 meters of groundwater drawdown beneath the road.

This volume presents selected papers from IACMAG Symposium,The major themes covered in this conference are Earthquake Engineering, Ground Improvement and Constitutive Modelling. This volume will be of interest to researchers and practitioners in geotechnical and geomechanical engineering.

Provides information on woven and non-woven geotextiles used for filtering and drainage in geotechnical engineering. The design of such filters balances large pores for adequate permeability with smaller pores for proper soil retention. Of the 15 papers from a June 1995 symposium in Denver, Colorado

President Carter's 1980 declaration of a state of emergency at Love Canal, New York, recognized that residents' health had been affected by nearby chemical waste sites. The Resource Conservation and Recovery Act, enacted in 1976, ushered in a new era of waste management disposal designed to protect the public from harm. It required that modern waste containment systems use "engineered" barriers designed to isolate hazardous and toxic wastes and prevent them from seeping into the environment. These containment systems are now employed at thousands of waste sites around the United States, and their effectiveness must be continually monitored. Assessment of the Performance of Engineered Waste Containment Barriers assesses the performance of waste containment barriers to date. Existing data suggest that waste containment systems with liners and covers, when constructed and maintained in accordance with current regulations, are performing well thus far. However, they have not been in existence long enough to assess long-term (postclosure) performance, which may extend for hundreds of years. The book makes recommendations on how to improve future assessments and increase confidence in predictions of barrier system performance which will be of interest to policy makers, environmental interest groups, industrial waste producers, and industrial waste management industry.