The alignment of the new rail line, which connects Khulna port and Mongla city, passes across the river Rupsha, which necessitates for a railway bridge near the existing road bridge. Pile foundation is designed as bored cast in-situ pile of diameter 1.5 m at the approach bridge and 2.5 m diameter at the main bridge portion. The prevailing geotechnical condition at the bridge location consists of strata of soft to medium silt/clay, poses great challenges in designing and execution of pile foundations. Pile load test, which was conducted on 1.5 m diameter pile of 40 m long pile, proved the inadequacy of the pile to achieve the required design capacity of 570 tons and it experienced huge settlement. Hence to meet the required capacity without increasing the length of pile substantially, base-grouting technique was implemented based on subsequent load tests on piles of various lengths with and without base-grout have been conducted. The test results on the base-grouted pile were satisfactory over non-grouted piles. This paper describes the experience gained in pile foundation with base grouting and the comparative study between base-grouted and non-grouted piles.
Subjects: Pile foundation, base grouting
Author: Vignesh R., Engineering Manager, Rahul S., Asst. Engineering Manager and Visakan R., Engineering Manager
Publisher: DFI