International Research Journal of Engineering and Technology (IRJET)
e-ISSN: 2395-0056
Volume: 12 Issue: 05 | May 2025
p-ISSN: 2395-0072
www.irjet.net
A NUMERICAL STUDY ON THE PERFORMANCE OF DEEP EXCAVATIONS BY COMPOSITE SHORING SYSTEM Eshwaraprasad M1, L. G ovindaraju2, 1Post graduate student, Dept. of Civil Engineering, UVCE College (University), Bangalore
2Professor, Dept. of Civil Engineering, UVCE college (University), Karnataka, India 560056
---------------------------------------------------------------------***--------------------------------------------------------------------1.1 Micropile Abstract - Ground improvement is a crucial aspect of geotechnical engineering, enabling engineers to modify the natural state of the soil to meet project requirements. Slope stability is a critical concern, as unstable slopes can lead to catastrophic failures, resulting in widespread damage, loss of life, and economic disruption. Nailing and micropile is known as one of the most used methods of slope stabilization. This research study focuses on the analysis of a composite shoring system of micropiles and grouted nails for slope stabilization. A number of sections with varying heights were analysed using Plaxis 2D ultimate finite element software, considering MohrCoulomb model are used to define soil parameters. homogeneous, heterogeneous soil, and rock properties are considered. It is observed that the effects of shear force, bending moment, and displacement on the stability of the slope are examined, and the factor of safety (FOS) is calculated for each section. The results demonstrate the effectiveness of the composite shoring system in improving slope stability. This study provides a valuable contribution to the field of geotechnical engineering, offering insights into the design and analysis of composite micropile and grouted nail systems for slope stabilization.
In modern geotechnical engineering, the demand for innovative, efficient, and adaptable foundation solutions has led to the increasing use of micropiles. These small-diameter, drilled and grouted piles have proven especially valuable in situations where conventional foundation methods are impractical or insufficient, particularly in challenging ground conditions and confined construction environments. Micropiles are typically less than 300 mm (12 inches) in diameter and are constructed by drilling a borehole, inserting a high-strength steel reinforcement element, and filling the void with cement-based grout. Unlike traditional displacement piles, micropiles are installed with minimal disturbance to surrounding soils and structures.
1.2 Soil Nailing Soil nailing is a cost-effective method for reinforcement of slopes and construction of retaining walls in a top-down manner. This method of soil reinforcement employs steel tendons which are grout or drilled into the soil to form a composite mass similar to a gravity wall. Soil nails are installed at an angle ranging between 10 and 20 degrees to the horizontal and are most often in tension. It is the deformation of materials that are retained during the excavation process that passively applies tensile stress to the soil nails. The purpose of soil nailing is commonly to secure and support slopes and excavations where superstructure construction sequentially occurs from the top.
Key Words: Slope Stability, Micropile, Grouted Nail, Composite System, Plaxis 2D, Mohr-Coulomb, Axial Force, Shear Force, Bending Moment, Displacement and Factor of Safety (FOS).
1.INTRODUCTION Deep excavation is a fundamental aspect of geotechnical and civil engineering, involving the removal of substantial volumes of earth to create space for structures such as basements, underground parking garages, tunnels, subways, and other subterranean facilities. As urban areas continue to grow and the demand for vertical construction become increasingly common, particularly in densely populated cities where space is limited and infrastructure must extend below ground level. The process of deep excavation requires careful planning, design, and execution due to the significant geotechnical, structural, and safety challenges it presents. Unlike shallow excavations, which are relatively simple and typically require minimal support, deep excavations often encounter complex soil conditions, high groundwater levels, and adjacent structures that can be sensitive to ground movement.
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2. Material and methods The study aims to evaluate the stability and safety of deep excavations, ranging from 13m to 21m in depth, subjected to varying surcharge load. The excavations are supported by composite shoring system of Micropiling and Nailing. A finite element based numerical analysis geotechnical software PLAXIS 2D VERSION 24 is used for the numerical analysis purpose. The soil profile is geometrically modelled and the properties of the soil and other elements are created and assigned. The analysis involves staged construction, with the factor of safety evaluated at each excavation stages. The objective of the study is investigating the effectiveness of these support systems in maintaining excavation stability and identify potential failure mechanisms. The results of this study will provide insights into the design and performance
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