More and more tunnels are being excavated every year, producing millions of cubic metres of rock, soil and water to be disposed of within legal and sustainably sensitive approaches. To date, there is no, consolidated guideline available to suggest how this may be achieved in an environmentally and socially responsible manner. This document will strive to suggest what is and is not suitable and further describe using numerous Case Studies, what can be done as practical mitigations.
Several Case Studies and Project Examples are presented that describe novel methods for handling, treating and disposing of products of excavation;
i.e. solids, liquids, dust and gases within the available technologies and site restrictions. In several cases, the combination of ground and groundwater conditions were so egregious that very creative site-specific means and equipment were developed and successfully implemented. In two cases, challenging subsurface conditions were complicated with the presence of methane and hydrogen sulphide gas.
Legal and regional spoil treatment and disposal regulations are increasingly restrictive on the use of industrial (biodegradable) chemicals frequently used for soil conditioning and ground improvement operations. The regulations have impacts that result in delays and deferments of significant and strategically important infrastructure projects around the globe.
It is expected that additional publications will follow that will provide more details and Case Studies on the national and regional requirements for tunnel spoil handling, treatment and disposal options. As described herein, this is a global challenge and one that confronts all significant tunnelling and underground construction projects.