Back Issues 11-20

THE FORMATION MECHANISM AND CONSTITUENT ELEMENTS OF ROAD SINKHOLES AND THE RELATIONSHIP WITH SHEAR BANDING 

Tse-Shan Hsu

President, Institute of Mitigation for Earthquake Shear Banding Disasters

Professor, Feng-Chia University, Taiwan, R.O.C., This email address is being protected from spambots. You need JavaScript enabled to view it.

Yu-Chien Wu

Ph.D. Student, Ph.D. Program for Infrastructure Planning and Engineering, 

Feng-Chia University, Taiwan, R.O.C.

Zong-Lin Wu  

Assistant Professor, National Chin-Yi University of Technology, Taiwan, R.O.C.

Ching-Chang Lin, Da-Jie Lin

Associate Professor, Feng-Chia University, Taiwan, R.O.C.

Abstract

Traditional scholars assert that in the development of road sinkholes, the tunnels and caves required respectively for the passage and storage of spalled subgrade soil would have been formed by the dissolution of limestone by groundwater. However, road sinkholes only appear locally and can also appear in layers of hard-to-dissolve gravel and mudstone. Therefore, the authors propose a different formation mechanism and constituent elements for road sinkholes based on shear banding and draw four conclusions from the results of a simulation analysis and test and case study: (1) sinkholes only appear locally in shear banding areas; (2) the water required for the development of road sinkholes is rainwater that has infiltrated through cracks in the road surface course that are present in incomplete structural systems; (3) the reasons for the formation of road sinkholes is the loss of integrity of the road structure system and the fact that seismic design codes do not fortify against shear banding; (4) if the inclination angle of a retaining wall is less than https://ijoi-online.org/f78953c8-3b1f-467e-82ad-c0556b40ea18" width="10" height="15" />, deep excavation construction will not induce the shear bands in the backfill region that are required to develop sinkholes. Based on the above four conclusions, it is suggested that the integrity of road structure systems should be maintained and seismic design codes should also specify fortification against shear banding. Only in this way can the formation of road sinkholes be avoided.

Keywords: sinkhole, tunnel, cave, shear banding, rainwater, excavation.