Performance Evaluation of a Slope Reinforced with Recycled Plastic Pin

Transportation Research Record

Hossain

Nobahar

2021

The recycled plastic pin (RPP) is made from recycled plastics and waste materials (i.e., polymer, sawdust, fly ash, etc.). It is a lightweight material and is less susceptible to chemical and biological degradation than the alternative reinforcing element. RPPs are driven into the slope face and provide additional resistance along the slip surface which increases the factor of safety against shallow slope failure. The current paper summarizes a case study using RPPs to repair highway slopes, investigating the use of a finite element method, and summarizes a design method. The highway slope was located over US 287 near the St. Paul overpass in Midlothian, Texas. The surficial movement had taken place over the slope, resulting in cracks over the shoulder near the bridge abutment. Three 15.2-m sections over the slope were reinforced using RPPs. After RPP installation, the slope was instrumented with inclinometers, rain gauges, moisture sensors, and water potential probes, and was monitored periodically. The performance monitoring results indicated that RPP provides resistance in the slope constructed using highly plastic clay. Further analysis of the slope using finite element analysis indicates that RPP can significantly improve the marginal slopes to a factor of safety more than 2.0. Finally, a simple design chart is presented to calculate the capacity of RPPs for slope repair design using an infinite slope approach.

Section: Project Backgroundmentioning

confidence: 92%

mentioning

confidence: 99%

Stabilization of the Highway Slope using Recycled Plastic Pins

Transportation Research Record

Hossain

Nobahar

2021

“…The crawler mounted rig with pseudo-vibratory hammer system works effectively for installation of RPP Khan et al, 2013). During the current study, the similar installation method was followed.…”

Section: Field Installationmentioning

confidence: 98%

Temporary Lateral Support of a Concrete Retaining Wall Footing Using Recycled Plastic Pin

Geo-Congress 2014 Technical Papers

Asce

Lozano

et al. 2014

Recycled Plastic Pins (RPP) are predominantly high density polyethylene materials that are fabricated from recycled plastics and other waste materials. It is a light weight material and less susceptible to chemical and biological degradation. The environmental resistant behavior of RPP makes it an attractive alternative compared to other degradable structural materials. Previous study indicates that RPP was successfully utilized for slope stabilization, arch bridges and piles. The current study presents the application of RPP as a temporary lateral support of a concrete retaining wall footing on a slope. The slope is located along highway Loop 12 near Union Pacific Rail Road (UP RR) over pass in Dallas, Texas. The concrete retaining wall is located at the middle of the slope that divided it into top and bottom slope. The crest of the top slope settled as much as 30 cm and footing of the retaining wall slid away from the top slope and resulted severe cracks near a construction joint. The site investigation program indicated that the sliding of the retaining wall occurred due to lack of lateral support. As a temporary remedial measure for 1-2 years, certain sections of the slope were reinforced using RPP. The spacing of RPP at the top and bottom slope was 0.9 m c/c and 1.2 m c/c, respectively. In addition, the first row of RPP at bottom slope was installed at the edge of the retaining wall footing and smaller spacing (0.6 m c/c) was provided near the critical cracked zone to provide additional resistance. After installation, topographic survey was conducted on monthly basis to monitor the lateral displacement of the stabilized slope. The field performance results indicated that the top of the retaining wall displaced as much as 15 to 20 cm after installation of RPP. On the other hand, 4 to 12 cm displacement was observed at the bottom of the wall which was less compared to the displacement at the top. RPP at the bottom slope provided resistance against the sliding and resulted less displacement at bottom slope.

“…Based on the available literature, 3.05 m (10 ft) and 2.44 m (8 ft) long RPP had been utilized to resist the shallow slope failure where the failure depth generally ranged between 0.9 m (3 ft) to 1.8 m (6 ft) . In addition, the 3.65 m (12 ft) long RPP has the possibility to be installed in the slope using available installation method suggested by Sommers et al (2000) and Khan et al (2013). Therefore, the 3.65 m (12 ft), 3.05 m (10 ft) and 2.44 m (8 ft) long RPP is selected for the parametric study.…”

Section: Parametric Study: Effect Of Spacing and Depth Of Rppmentioning

confidence: 99%

“…The slope is located over highway US 287 near St. Paul overpass in Midlothian, Texas. The detail of the study is presented in Khan et al (2013). During the current study, the slope over US 287 is selected as a reference slope.…”

Section: Introductionmentioning

confidence: 99%

Numerical Study of Slope Stabilization Using Recycled Plastic Pin

Geo-Congress 2014 Technical Papers

Hossain

Lozano

2014

Moderate (3H : 1V) to steep (2.5H : 1V) slopes and embankments underlain by expansive clayey soils are susceptible to shallow land sliding during intense and prolonged rainfall events. These failures are predominant in North Texas area and cause significant maintenance problems for the Texas Department of Transportation (TxDOT). The Recycled Plastic Pin (RPP) has potential to be utilized in slope stabilization as a remedial measure of shallow slope failure. A parametric study was conducted to evaluate the effect of different spacings of RPP on the factor of safety and deformation of the slope. The objective of the current study was to investigate the effect of spacing and length of RPP over the factor of safety using Finite Element method (FEM). The analysis was conducted using 2D FEM software package PLAXIS 2D and factor of safety of the slope was determined using the strength reduction technique. A highway slope constructed using high plastic clayey soil, located over US 287 near St. Paul overpass in Midlothian, Texas was selected as reference slope. The strength of the slope was back analyzed using PLAXIS 2D at factor of safety equals to unity. As a remediation technique, RPP was selected for the slope stabilization and the slope was analyzed with different lengths (2.44 m to 3.65 m, 8 ft to 12 ft) and spacings (0.61 m c/c to 2.44 m c/c, 3 ft c/c to 8 ft c/c) of RPP. The FEM results indicated that RPP provided resistance against the shallow failure and resulted increment in factor of safety by shifting the failure plane to a deeper depth toward deep seated failure. In addition, the factor of safety increased with the increment in RPP length as higher resistance was observed from the foundation soil. The factor of safety of the reinforced slope remained almost constant up to RPP spacing of 1.5 m (5 ft) c/c and then decreased with further increment in spacing. The horizontal deformation of the slope was greater with the increment in spacing of RPP.