Jet Grouting in Karstic Limestone, Cape Girardeau, Missouri, USA

Cape Girardeau, Missouri
1998 - 2000

A cable stay bridge was being constructed between southern Missouri and southern Illinois. Extensive karstic features were discovered in the limestone formation under the central pier. Jet grouting was determined to be the most feasible method to remediate the founding material.

Triple fluid jet grouting (air, water and grout) was the method of choice for eroding and removing the clay features and replacing it with a cement grout. Jet grouting took place at elevations between 100 and 150 feet below the platform elevation. Over 200 jet grout columns were installed.

ECO provided site inspection and quality assurance to verify that the jet grouting was performed in accordance with the specifications.

Throughout the course of the project the jet grouting parameters were optimized and additives were used to improve the erosion and removal of clays. The cement content in the spoils was constantly verified and by applying the “mass balance” theory, the (theoretical) size and composition of the columns were determined.

This project was one of the first applications of jet grouting in karstic limestone. The successful completion of the jet grouting was, in part, due to the partnering between all the parties involved in project.