Evaluation of geosynthetic anchor systems through pullout testing

February 1st, 2018 / By: , / Feature

Anchor systems are a vital portion of any erosion control program tasked with negating the effects of erosive forces on disturbed soils. Anchor systems are typically deployed in situations where a rolled erosion control product (RECP) is to be used as the primary erosion control measure. As more RECPs, especially high-performance turf reinforcement mats (HPTRMs), […]

 

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3 responses to “Evaluation of geosynthetic anchor systems through pullout testing

  1. This was a very useful article. Here in Australia, Cirtex get involved in delivering Platipus Anchor Systems & Solutions and would agree that people or specifiers do not pay much or enough attention to type of anchor or load verification with erosion matts in severe inland & coastal area applications. At least with Platipus we have tools to load verify and there is science behind the anchor load determination with Terzaghi & Skempton soil theories. Many thanks for this article it was interesting – Dave Markham

  2. My professional Geotechnical Engineering experience with clay slopes, PI from 15 to 35, is
    that over the long term (years, not minutes) the behavior of the soils will yield and deflect. Be careful at applying a several minute test to a long term installation. Some clay soils will also corrode bare steel. Long term performance is difficult to come by except by lawsuit experience.
    robertrogersge@aol.com

  3. Anchor testing should be performed with the load applied perpendicular to the direction of the axis of the anchor. Anchors are most often used to counteract the forces of gravity as they work upon the geocell on a slope. The anchors are driven perpendicular to the slope and the force upon the anchor is parallel to the slope, not in the direction tested in this study.

    There is some relevance, because as an anchor slices through the soil and the anchor begins to fail… A small component of the force translates to the axis of the anchor. But more importantly, any anchor that connects to the bottom of the wall of the geocell will be overrun as the geocell/infill mattress slides right over the top of the connection.

    The extremely small diameter of wire pins and wire spiral products lead to bending of the anchor systems. The J-hook is not an acceptable solution due to the difficulty of driving them into the ground as the top of the J does not align with the axis of the remainder of the pin (leading to frustration by crews) and the J-hook shown in the image on this report is not the standard 1/2 inch rebar but appears to be a smaller diameter as well.

    We recommend the ATRA stake clip over 1/2 inch rebar or better yet the ATRA speed stake. These products produced by Presto Products have been proven superior on thousands of installations. https://www.prestogeo.com/products/soil-stabilization/geoweb-atra-accessories/atra-anchor/

    Another important factor to consider is the number of stakes required. My understanding is that the spiral two-piece solution requires an order of magnitude more units to compensate for its reduced holding power.

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