01333091

Component

At the present time, the computer program DRIP has been used as a numerical analysis tool for design of subsurface drainage in a pavement system. The SEEP/W program, however, provides an alternative analysis tool for transient water flow analysis that can take into account of variation of hydraulic conductivity with water content of unbound base materials and complex pavement layers, geometry and dimension of a pavement section, and the use of subsurface drainage pipes. This paper presents the results of a comprehensive parametric study of representative pavement subsurface drainage system using two-dimensional SEEP/W program. The parameters studied include the base hydraulic conductivity, subbase hydraulic conductivity, base layer thickness, pavement cross-slope, drainage length, base D60 gradation, and the location of edge drain. A statistically derived regression equation together with design charts are presented for estimating time to drain 50% of free water in a pavement system. Observations based on parametric analysis results and comparisons between DRIP analysis and SEEP/W analysis are provided for facilitate effective subsurface drainage design. Although saturated hydraulic conductivity of base material is an important factor, other factors such as Soil-Water Characteristic Curve (SWCC) variation of hydraulic conductivity with water content (degree of saturation), pavement geometry and dimensions, use of subsurface drainage pipes are also important in controlling the effectiveness of a pavement subsurface drainage system.

01329018

11-3099

English

18p

2011

Transportation Research Board 90th Annual Meeting

DVD

Figures (8) ; References (21) ; Tables (4)

Flexible pavements; Hydraulics; Runoff; Soil water; Subbase (Pavements); Subsurface drainage

Soil water characteristic curve

Highways; Pavements; I22: Design of Pavements, Railways and Guideways

Transportation Research Board Annual Meeting 2011 Paper #11-3099

TRIS, TRB

Feb 17 2011 6:24PM