November 24, 2024
Abdoreza Fazeli

Abdoreza Fazeli

Academic Rank: Assistant professor
Address:
Degree: Ph.D in Civil Engineering
Phone: -
Faculty: Faculty of Engineering

Research

Title
Study of the uplift load capacity of gravel impact compacted piers using the injected rammed steel anchors
Type Thesis
Keywords
بار بركَنش، پايه هاي تراكمي ضربه اي شني، ريزشمع خاردار، تزريق
Researchers Bahman Niroumand (Primary advisor) , Abdoreza Fazeli (Advisor)

Abstract

This research examines the uplift load capacity of a new generation of stone columns known as gravel impact copaction piers, which uses the driving of rammed steel anchors into these piers along with the injection of cement slurry with a specific mixing plan to resist with the uplift loads. For this purpose, a series of field tensile loading tests were conducted on six test piers at the 525-hectare coastal site in Bushehr Port at the age of 28 days. The gravel piers with an initial diameter of 0.6 meters and an embedded length of 4.8 meters, while the steel micropiles featured an external diameter of 110 mm, and the soil used in this study consisted of CL soil to a depth of 0.9 meters and CL-ML soil to a depth of 10 meters, which were relatively soft. By conducting a comprehensive analysis and comparison of the results obtained from field loading tests, including pullout-displacement load, spring modulus, and ultimate bond strength, a favorable investigation was carried out to optimize the installation location of the barbed. The net bearing contribution of each barbed and the impressionability of the barbeds from the resistance parameters were also assessed. The increase in ultimate pullout load capacity and ultimate bond strength of barbed micropiles compared to simple micropile is equal to 23% for micropiles with two barbeds at the end, 29% for micropiles with two barbeds in the middle, 51% for micropiles with two barbeds at the end and two barbeds in the middle, 38% for micropiles with four barbeds at the end, and 45% for micropiles with four barbeds in the middle. This study demonstrates that distributing stress across multiple barbeds reduces the concentration of stress on each one, thereby enhancing the uplift-bearing capacity of the micropiles. In fact, in micropiles with fewer barbeds, the energy absorption and stress applied to each barbed are higher. Consequently, the net bearing capacity share of each barbed in micropiles with two barbeds is higher than