Infiltration tests were conducted on soil columns of silty sand over pea gravel, concrete and to investigate the capillary barrier effect an underlying coarser layer. Water movement across interface occurred when suction head at reached breakthrough lower layer, defined as which layer first became conductive, regardless infiltration rate or properties overlying finer Thus, controlled in this study. After was terminated, near increased above restored. The did not change substantially after...

This paper presents a method to estimate the additional storage capacity derived from presence of capillary break or barrier beneath soil layer used in surface cover system. The involves first estimating suction head profile at breakthrough. Then, using relationship between and water content (i.e., moisture characteristic function), corresponding is derived. Integrating over depth yields total which net can be determined. Good agreement was obtained calculated this those numerical...

Accumulating data on traditional compacted soil-surface covers are demonstrating that they likely to degrade and have reduced effectiveness as long-term barriers; therefore, suitable alternatives being examined. One possible alternative is receiving increased attention capillary barriers. The U.S. Environmental Protection Agency (USEPA) allows for be used, but requires achieve infiltration erosion protection equivalent of designs contained in design guidance documents. A method comparing a...

Abstract Annular cement can be compromised due to suboptimal placement or operational and environmental loads during the lifetime of well. This result in sustained casing pressure, several sealing materials are offered as solutions repair faulty cement. paper presents a review current treatment novel experimental methodology for testing effectiveness injected into full-scale diameter test section with debonded inner casing. A cell was constructed consisting two concentric sections 9 5/8-in...

Unsaturated drainage layers (UDLs) have been demonstrated to greatly increase the lateral diversion capacity of capillary barriers. The inclusion a UDL allows native soils suitable for vegetation growth be used as finer soil properties layer no longer need considered. A comprehensive numerical study was conducted investigate influence interface slope and material on system's ability laterally divert downward moving moisture. barrier system with without simulated 10 years using daily varying...

The water retention functions of four nonwoven polypropylene geotextiles were measured. Each the geotextile types tested in two conditions: new and cleaned. each specimen found to be hysteretic. specimens always contained more at comparable suction heads than cleaned specimens. At zero head, approached saturation, whereas less 20% saturated.

Ross' solution for the divergence capacity of a capillary barrier is modified to incorporate constant hydraulic conductivity anisotropy fine layer. The analysis assumes steady infiltration and that principal directions tensor are parallel normal fine‐coarse contact. solutions length have two terms. first term, similar Ross, represents diversion due presence proportional second which arises from into an anisotropic medium independent barrier, function layer thickness will be small engineered...

Geotextiles are increasingly being used in a wide variety of applications, such as reinforcement, separation and drainage. These geotextiles often contact with unsaturated soils; however the hydrologic behavior geosynthetic materials environments is most ignored because basic characterization these does not exist. Test methods for measuring water retention data transmissivity under suction have been developed nonwoven geotextiles. measurements complement simple angle capillary rise to...

Thousands of abandoned wellbores may lie within the aerial extent a CO2 storage operation. These represent potential leakage pathway and leaky wellbore needs to be re-completed or otherwise repaired restore seal integrity ensure containment stored CO2. Due high cost recompleting well, sufficient economic incentive exists if viable repair technology is available. In this paper, we examine use epoxy nanocomposites as materials that have excellent bond characteristics with both steel cement...

Multiple fluids are likely to exist in fractures and flow paths associated with leaky wellbores, including liquids (e.g., crude oil) gases gas ex-solved from liquid). These occupy move through different portions of the pore spaces within depending on many factors, fluid properties, fracture size, amount fluids. Upward leakage any phase, fracture, can contaminate water-bearing formations, create hazardous surface conditions, compromise functionality wellbore. Early signs wellbore leaks may be...

Because of the multiple layers dissimilar materials and large deformations involved in subsidence a landfill system, large-scale computer simulation geomechanical response to with use conventional numerical methods are problematic. The Material Point (MPM), which was recently developed for dynamic problems such as penetration perforation, is newly emerging method. MPM modified this paper simulate cover system that includes geomembrane under quasi-static loading conditions. Sample problems,...

Water movement in pavement sections that included an edgedrain trench was investigated by means of numerical simulations explicitly unsaturated water flow. Most the resulting from infiltration response to simulated rainfall events occurred under conditions, is, negative pressures. Fully saturated conditions and positive pressures most often only occur drainage bottom. Drainage efficiency shown depend on base course backfill material properties configuration. The hydraulic conductivity not be...