# Effect of Using Plastic Waste Bottles on Soil Response above Buried Pipes under Static Loads
## 1 Introduction  
Buried pipes are typically used to convey water, natural gases, etc. They are considered lifelines because they transport important substances [1]. The importance of pipeline ruptures is deemed to be economical, technical, and social. Several researchers concentrated on ways to protect buried polyvinyl chloride (PVC and uPVC) pipes under various conditions of loading. However, little research has been conducted on the protection of buried pipelines using recycled materials such as plastic. The authors of [2] studied the performance of strip footing under static loading reinforced with geocell and geotextile reinforcement. Various parameters were adopted in the experimental testing program, including reinforcement width, number of geotextile layers, and height of geocell below the model footing. The finding of the experiments showed improvement in ultimate bearing capacity and a reduction in footing surface settlement. Geosynthetic reinforcement reduces foundation settlement and improves the bearing capacities of foundations [3; 4; 5; 6]. [PERSON]. [8] conducted laboratory experiments and numerical models to study the performance of buried structures such as tunnels, culverts, and bridges (corrugated steel plate structures). Various factors have been considered, including the nature of backfill soil, backfilling sequence, soil cover height, the effect of geotextile reinforced backfill, corrugated profiles, and the soil-structure interaction under different loading conditions. Numerous researchers have examined the protection of shallow buried pipes using geogrid-reinforced soil beds under static loading [9; 10; 11; 12; 13]. There is growing concern about the effect of plastic waste on the environment, recognizing the urgent need to reduce our plastic consumption. A clean and green way ofreusing post-consumer polyethylene terephthalate (PET) bottles is by turning them into valuable building material--either directly or their polymer. An efficient and simple way of reusing discarded plastic bottles is in underground applications as soil reinforcement. The good mechanical characteristics of such discarded polymers make them a viable alternative to present geosynthetics such as geogrid, geocell, and geotextile. Not only would this reduce the pollution of the environment, but it would also improve soil properties while lowering polymer consumption as first-use geosynthetics, in addition to avoiding problems associated with incineration and the costs of their physical removal or recycling. Improvement in soil mechanical properties and strength parameters due to the inclusion of the waste plastic bottle reinforcement has been studied by [14; 15; 16; 17; 18]. This literature studied the effect of using a mixture of crushed PET plastic bottle chips, PET fibers, or plastic sheets with soil as reinforcing elements. Currently, waste sand-filled PET plastic bottles are in use as a cheap construction material in some countries for the building of shelters (Figure 1a; source: UNHCR) and retaining walls (Figure 1b; source: Built it International), yet using plastic bottles in its original form for reinforcement of soil beds to improve their properties and to reduce environmental pollution is a relatively unfamiliar idea. There is not much available research on the role of uncrushed-form horizontally or vertically sliced plastic bottles in improving soil behavior and strength parameters [19; 20; 21; 22] under static loads. Thus, the behavior of soils reinforced with waste plastic bottles under static loads needs further investigation. Recently, [PERSON] and [PERSON] [23] conducted laboratory experiments on a PVC pipe buried in geocell-reinforced and unreinforced sand beds. The performance of pipes installed in sand bedding was studied, along with the various parameters that influence that performance. The findings of this research were presented in terms of the vertical crown pressure above the pipe, the surface settlement of the soil, and the crown's displacement amplitude.