This practice is intended to provide installation guidance for designers, specifiers, installation contractors, regulatory agencies, owners, and inspectors who are involved in the planning and installation of geocomposite pavement edgedrains and underdrains. As with any standard practice, modification may be required for specific project conditions or for special local or regional conditions. Fig. 1 shows the proper horizontal alignment of the drain based on various trench conditions outlined in 9.2, and the vertical depth of placement of the drain needed for a geocomposite edge drain to function most effectively as both a collector and conduit.

Fig. 2 shows the typical type and arrangement of equipment used to install geocomposite highway edgedrains. The combination of these recommended installation conditions, techniques, and equipment are critical to the satisfactory long term performance of these products.

1.1 This practice covers recommendations and identifies pertinent areas of consideration for the installation of buried geocomposite drains used for highway edgedrains, under-drains, or other pavement drainage applications meeting the requirements of Specification D7001. These recommendations are intended as guidelines for developing a satisfactory construction and installation method to minimize installation-caused deformation or damage and to provide long-term performance of these products. It is also intended as a guideline for ensuring a stable underground environment for these materials under a wide range of service conditions. Because of the numerous and diverse product designs available and the inherent variability of natural ground conditions, achieving satisfactory performance of any one product may require review by the engineer and modification to provisions contained herein to meet specific project requirements.

1.2 The scope of this practice necessarily excludes product performance criteria such as compressibility in any plane, flow capacity, inlet capacity, or geotextile selection and use. It is, therefore, incumbent upon the product manufacturer, specifier, and project engineer to verify that the product specified for an intended application, when installed according to procedures outlined in this practice, will provide satisfactory long term performance according to criteria established by the owner for that application. A commentary of product performance and installation factors important in achieving a satisfactory installation is included in Appendix X1.

1.3 The values stated in SI units are to be regarded as the standard. The inch-pound units given in parentheses are for information only.

1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.