Quantitative methods for predicting underground construction waste considering reuse and recycling

Abstract

The construction industry has been greatly developed in the past few decades, especially in the extensive use of underground space. The increasing amount of waste (e.g., soil, sludge, and rock) generated in the underground construction constitutes an important part of construction and demolition waste (CDW) but the related problems are rarely addressed in an independent quantitative study. In order to facilitate recycling of underground construction waste (UCW), quantitative methods for predicting UCW are proposed based on mass conservation in this study. Through on-site investigation and literature review, the source characteristics of UCW and corresponding recycling potential are firstly analyzed. Secondly, the corresponding quantitative mothed is proposed for predicting each type of UCW according to the principle of mass conservation. Finally, the proposed quantitative methods are applied in two real underground infrastructure projects to verify the accuracy. The results show that the accuracy of quantitative methods for predicting shield sludge and engineering soil is 82.03%-95.79% and 94.49% respectively. In addition, detailed geological and geotechnical analysis is the key to accurate management of waste generated in underground civil and infrastructure projects. In both cases, underground construction produced a large amount of construction waste with great recycling potential. UCW can theoretically reach 100% recycling, and full reuse and recycling of UCW will bring huge economic value and be conducive to the sustainable development of the construction industry.

The Potential of Recycling and Reusing Waste Materials in Underground Construction: A Review of Sustainable Practices and Challenges

“…In recent years, several tunneling projects, such as Delhi Metro Pink Line Project in India, Marmaray Rail Tunnel in Turkey, Gotthard Base Tunnel in Switzerland, and Sydney Metro Northwest in Australia, implemented advanced TBMs equipped with sensors and sorting mechanisms to classify spoil like sludge, soil, and recoverable sand-gravel. A significant percentage ranging from 70% to 96% across projects was recycled and reused [4,23,32].…”