A study on pile group with adjustable rigidity subjected to large horizontal displacement

Abstract

The segmental pile system, which is composed of alternating concrete blocks and rubber sheets, connected with anchor cable is a non-continuous system. The rigidity of the pile system may be adjusted by tensioning the anchor cable. There is a question of whether it can be treated as a beam which is a continuous system. The working mechanism is through the friction developed at the joints. The primary objective of this study is to compare this behavior of the non-continuous pile system with the continuous pile system with adjustable rigidity. To be able to adjust the rigidity of the continuous pile system, water pressure in a confined rubber cylinder is used. Three-point bending, oedometer, and large displacement model pile tests are conducted to investigate the behavior of the model piles subjected to horizontal displacement. Model pile tests on a continuous single and 3 x 3 pile groups with 2.4D spacing are conducted. Various pile-soil modulus ratios are studied with the help of the piles with adjustable rigidity and embedded in poorly graded sand compacted to different relative densities. The experiments are conducted on fixed-head piles at large displacements of up to 50 mm (pile diameter, D is equal to 35 mm). The model pile group system can withstand large displacements without failure. Limited to the test and boundary conditions applied, the lateral capacity of the pile group is related to pile-soil modulus ratios. In conclusion, the non-continuous pile system and the continuous pile system showed similar load-displacement behavior. Although, the mechanisms leading to horizontal capacity development for both pile systems are completely different.