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A CSPE (Hypalon) primer
January 1st, 1970
By Steve Roades Chlorosulfonated polyethylene (CSPE) geomembranes have a history of providing long-term performance in exposed environments. These geosynthetic barriers are increasingly referred to generically as CSM, but many people still refer to them by the no-longer-produced Hypalon elastomer brand name. DuPont, which had manufactured the Hypalon elastomer formerly used in the lion’s share of […]
How do wick drains work?
January 1st, 1970
By Ron Bygness The term wick drain is a misnomer because these clever devices do not actually wick away water. Wick drains, perhaps more accurately called strip or prefabricated vertical drains (PVDs), accelerate preconstruction soil consolidation. The drains are composed of a plastic strip with drainage channels, wrapped in a nonwoven geotextile filter fabric (see […]
The influence of geogrid’s geometry and structure on interface behavior
January 1st, 1970
European experience in pullout tests By Daniele Cazzuffi, Lidia Sarah Calvarano, Giuseppe Cardile, Nicola Moraci, and Piergiorgio Recalcati 1. Introduction The use of geosynthetics to improve the soil mechanical response has become increasingly common practice in geotechnical engineering applications. Geosynthetic materials are commonly used in soil reinforced structures, in embankment toe reinforcements on compressible ground, […]
Central Valley Project
January 1st, 1970
By Jessica Bies Encompassing 35 counties, California’s Central Valley Project provides electrical power and water to farms, homes, and factories located within a 500-mile north-south stretch. One of the largest water conservation developments in the U.S., it was constructed to protect the Central Valley Basin from water shortages and floods. Approved by President Roosevelt in […]
Go with the flow
January 1st, 1970
By Jessica Bies Located in the Shasta and Trinity River Division, Whiskeytown Reservoir is just one stop in a system that diverts water from the Trinity River Basin into the upper Sacramento River. The water takes a complicated path through a total of two tunnels and three reservoirs including the one in Whiskeytown. This is […]
The benefits of GRS bridges
January 1st, 1970
By Jessica Bies Although GRS bridge technology is not suitable for every bridge building scenario, it can be a great option for replacing simple overpasses where severe flooding that could weaken a GRS structure is unlikely to occur. Here are some of the benefits of using GRS technology in appropriate settings. Bridges constructed with GRS […]
In this article…
January 1st, 1970
By Dov Leshchinsky and Fumio Tatsuoka There have been numerous failures of geosynthetic reinforced walls. The majority of these failures occurred in the private sector. This article does not look at the forensic of wall systems that failed due to exploited redundancy combined with ignorance or careless attempts to “economize” the structure. Instead, it explains […]
Apparent cohesion leads to eventual failure
January 1st, 1970
These photos show a wall failure next to a corner. This failure occurred in an area where successive triangular sectors of geogrid layers were not installed. Failure is to be expected because reinforced walls without reinforcement should fail. Curiously, this failure occurred about one year after the end of construction. Clearly, failure was delayed because […]
Wall failure after a typhoon
January 1st, 1970
This photo shows wall failure during a heavy rainfall caused by a typhoon. There was no adequate internal drainage in the fine-grained backfill although water in front of the wall was collected by a concrete-paved ditch. Redundancy due to apparent cohesion disguised the lack of proper drainage for four years, holding the wall system stable. […]
Inadequate compaction necessitates massive remedy
January 1st, 1970
These photos show a massive remedy utilizing anchors needed for an initially inexpensive geotextile reinforced wall. One reason that necessitated this remedy is poor compaction. Also, risers collecting surface water were embedded in the reinforced soil zone. These risers were connected sequentially by a 10-in. PVC pipe located in the reinforced soil. Differential settlement of […]