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High plasticity expansive clayey soils are prone to repeated swelling and shrinkage due to cyclic climatic variations. These variations lead to desiccation cracks that act as pathways for rainfall intrusion into the slope, and lead to increased moisture content. The increase in the moisture content of the soil generates considerable hydrostatic pre...
Citations
... The RPPs intercept potential sliding surfaces, thereby providing additional resistance to maintain long term stability of the slope [21]. Previous literature [10,21,28,32] have shown the innovative application of RPPs in stabilizing shallow slope failures across North Texas. The use of RPPs also reduces plastic waste from landfills, all the while providing a profitable market for recycled plastics [24]. ...
... Based on previous successful installations [21,28,32], a Link-Belt 350x4 model excavator with an NPK GH-15 model hydraulic breaker was used for the installation of the RPPs. First, the pins were positioned on markings previously established on the ground. ...
... This ensures that the RPPs do not buckle due to a high compression load. Previous field installations of RPPs [21,28] have demonstrated the use of steel pins in detail. It is to be noted that the compressive strength of the RPPs used in this field study was 31 MPa (based on manufacturer specifications). ...
Sliding failure of Mechanically Stabilized Earth (MSE) retaining walls is a common problem when the shearing resistance developed between the wall base and foundation soil is insufficient. Highway MSE wall base failures can cause significant maintenance, repair, and cost implications for the state department of transportation. Controlling base movement using Recycled Plastic Pins (RPP) can be a potentially cost-effective and sustainable solution. RPPs are primarily manufactured from recycled plastics and have been successfully used for stabilizing shallow slope failures. The objective of the current study is to demonstrate the effectiveness of using RPPs for increasing the sliding resistance of an MSE wall. Four field test sections were constructed, out of which three were reinforced with different combinations of RPP sizes and spacings, while one was left unreinforced as a control section. Regular performance monitoring of the test sections was conducted using vertical inclinometers along with earth pressure plates. More than a year of results indicated a 75-88% reduction in lateral displacement of the reinforced wall base when compared with the control section. Additionally, the lateral earth pressure on the wall facing was decreased by 55-72% in the reinforced sections compared to the control section.
... One such method could be the use of Recycled Plastic Pins (RPP). In recent years, RPP has been successfully used in different projects in the North Texas region, especially for shallow slope stabilization (Hossain et al. 2012;Khan et al. 2013;Khan et al. 2014;Sapkota 2019). RPP has a considerable amount of compressive as well as flexural strength (Bowders et al. 2003), which can carry the load both axially and laterally. ...
MSE retaining walls underlain by unsuitable soil are vulnerable to bearing capacity failure. One of the reasons for the bearing capacity failure of foundations constructed over such soil is excessive total and differential settlement. A common practice to reduce settlement of unsuitable foundation soil is excavation of the foundation soil and replacement with competent soil, which can be costly and time-consuming. The objective of the current study is to evaluate the use of recycled plastic pins (RPP) to reinforce foundation soils to improve the bearing capacity of MSE wall foundation. In this study, a large-scale field test has been conducted-two identical test sections (one control section and one RPP reinforced section) of 4.57 m × 4.57 m (15 ft × 15 ft) were constructed. Both sections were instrumented with horizontal inclinometer casings to observe vertical settlement. Based on the field data, a reduction of 75% vertical settlement was observed in the reinforced section compared to the control section. The preliminary data suggest a potential for the use of RPP for increasing the bearing capacity of MSE wall foundation.
Periods of prolonged rainfall events give rise to sloughing and surficial failures of slopes underlain by expansive clayey soils, resulting in significant maintenance costs for various transportation agencies. Recycled plastic pins (RPP) are a sustainable and cost-effective solution to stabilize such surficial slope failures due to their long-term endurance against degradation. The objective of the current study is to evaluate long term performance of shallow slopes stabilized with recycled plastic pins. Two highway embankments in North Texas, where cracks were observed along the shoulder due to surficial movement of the slopes, were stabilized using RPPs. Inclinometer casings were installed in the slopes to monitor the lateral movement, while topographical surveying was carried out regularly for monitoring the vertical settlement. The long-term performance of the stabilized sections was evaluated between 4 years and 7 years. Based on the study, it was concluded that RPP can be utilized as a sustainable solution for shallow slope failure.
