STUDYING THE PERFORMANCE OF MICROPILED SYSTEM IN SANDY SOIL SUBJECTED TO VERTICAL LOADS FOR IMPROVING BEARING CAPACITIES

Hassan, Eslam Ahmed; Elbanna, Wagdy Mohammed; Rabie, Mohammed Hasanin; Mostafa, Hussein Mahmoud

doi:10.21608/erj.2024.332468.1133

STUDYING THE PERFORMANCE OF MICROPILED SYSTEM IN SANDY SOIL SUBJECTED TO VERTICAL LOADS FOR IMPROVING BEARING CAPACITIES

Document Type : Original Article

Authors

¹ Civil, faculty of engineering - mataria branch , helwan university , Egypt, cairo

² Lecturer of Geotechnical Engineering, 15 May Institute in Cairo, Egypt.

³ Professor of Geotechnical Engineering, Helwan University, Cairo, Egypt.

⁴ Lecturer, Faculty of Engineering at Mataria branch, Helwan University, Cairo, Egypt

10.21608/erj.2024.332468.1133

Abstract

Micropiles are grouted piles with a small diameter. The bond between the grout and the surrounding ground depends on the grouting method. Type A as mentioned in FHWA 2005 is one of the common type of these methods that grout is placed under gravity head only. This technique is the most suitable for experimental work. This study explores the axial behavior and load-carrying capacity of micropiles in sand under vertical loading, highlighting the effects of the slenderness ratio (L/D) and water-to-cement (W/C) ratio on performance. The results demonstrate that micropiles with higher slenderness ratios (e.g., L/D = 14) and lower W/C ratios (e.g., 0.3) exhibit superior load-bearing capacity. Specifically, W/C = 0.3 achieved maximum loads exceeding 5886 N, while higher ratios (W/C = 0.55) significantly reduced strength and stiffness due to weaker grout properties. A mathematical model was developed to predict pile load capacity based on deflection, L/D ratio, and W/C ratio, providing a practical tool for optimizing pile design. This research emphasizes the importance of geometric properties and grout composition in enhancing micropile efficiency under various loading conditions. The validation of the model used was vitrificated with another model (Binu Sharma 2014). Load – settlement for all tests cleared in the present paper. Equation of pile load determination was derived as function of deflection of pile, W/C ratio and slenderness ratio L/D.

Keywords