Geotechnical Evaluation of Multi-Layered Simsima Limestone using Bi-Directional Static Load Test (BDSLT)

Static load tests are vital to assess the genuine behaviour of piles to substantiate the geotechnical design parameters and construction approaches. A load testing program was undertaken to determine the working capacity, skin friction, and settlement of drilled shafts in Simsima limestone, the predominant foundation stratum in Doha, Qatar. The weathering profile of the Simsima limestone is complex with the degree of weathering likely to increase with depth. This paper presents the performance of three preliminary instrumented bored cast-in-situ test piles (Type 1, Type 2 and Type 3) by Bi-directional static load test (BDSLT) using sacrificial hydraulic jacks, socketed in the weathering zones of Simsima limestone formation in Lusail FIFA World Cup 2022 stadium project, Qatar. The test piles were instrumented with vibrating wire strain gauge technology and were load tested using the BDSLT loading method to determine the pile-rock interactions within the various weathering zones of Simsima limestone. The unit shaft friction values obtained from the load test are compared with the initial design values. Results indicate that the skin friction was increased from values reported before pile load testing and was used for the optimization of pile design. BDSLT method with strain gauge instrumentation is a modern tool in value engineering of pile design to provide accurate information to the Qatar infrastructure foundation industry.