Academic and industry experts describe the use of chemical (permeation) grouting beneath an airport runway to improve ground resistance to liquefaction. They present the cost, environmental, and operational benefits; specifications; methodology; and practical results of this cutting-edge method. Because transportation infrastructure such as ports and airports are required to operate even in the event of a large earthquake, they must be resilient against liquefaction. Through contributions from experts in academia and industry, this book describes the discovery of construction defects at three airports in Japan and the subsequent project to repair and strengthen the ground using chemical grouting using environmentally friendly colloidal silica, the first time this technique was used in Japan. This book first describes chemical grouting and its benefits, its specifications, and field investigation results of its ground improvement performance. Next, it demonstrates a numerical and probabilistic method to model spatial variability in material properties of field data on improved ground. Finally, it explains a performance-based verification for airport runway availability in terms of bearing capacity and runway flatness after a large earthquake. Through its clear explanations, this book enables readers to implement chemical grouting and enjoy the cost, environmental, access, and operational benefits of this technique over traditional methodologies that would require temporary site closure and large-scale excavation. Because the concept and methodology described in this book are applicable to various geological, geotechnical, and seismological conditions depending on the location and structural and operational conditions depending on the infrastructure type, this book is a useful resource for geotechnical and other infrastructure engineers who must strengthen the ground without disrupting normal operations.