Publication Abstract

DFI - PFSF Piling & Ground Improvement Conference 2022 Proceedings, (DFI and PFSF)

Case Study of Geotechnical Challenges Involving Ground Improvement and Successful Completion of Pile Foundations in a Rail Road Project in India
Venkata S. Dronamraju

As a part of 115 km long new railway line project between Obulavaripalle and Krishnapatnam Port stations in southern part of India, two tunnels of 0.96 km and 6.62 km long were constructed using NATM method. The biggest challenge was to carry out tunnelling for a length of about 500m through shallow overburden locations of 4m to 6m in forested and hilly terrain. Designers recommended cut and cover method and alternative methods were explored to ensure faster Project completion. An innovative method of tunnelling was conceptualised and successfully carried out by ground improvement externally using grouting and micro piles besides controlled blasting with additional support system internally. Extensive monitoring was done with the help of instrumentation and total station survey both inside of tunnel and on ground surface during tunnelling. Faster execution through low cover zones resulted in savings in cost and time. There were swampy areas for a length of about 5 km where entering the area to carry out earth work for embankment posed a serious challenge. Lime modification and lime stabilization techniques were successfully employed and embankment works were completed. An important railway bridge was being constructed on River Pennar where the sub soil was predominantly sand for a depth of 8 to 10m underlain by clay up to a depth of more than 50m posing serious problems of collapse of soil and bore. Vibro hammer and other techniques were adopted to overcome the collapse problem and 360 piles were successfully completed.

 article #3841; publication #1076 (IC-2021)