International Research Journal of Engineering and Technology (IRJET)
e-ISSN: 2395-0056
Volume: 13 Issue: 01 | Jan 2026
p-ISSN: 2395-0072
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Geotechnical Investigation and Stability Evaluation of Cut Slopes in Highway Projects – Himachal Hilly Highway Section B Priyanka1, Lovepreet Kaur2, Kamalpreet Kaur3 1PG scholar, Dept. of Civil Engineering, SRM Global Group of Institutions, Haryana, India 2Professor, Dept. of Civil Engineering, SRM Global Group of Institutions, Haryana, India
3Professor, Dept. of Civil Engineering, SRM Global Group of Institutions, Haryana, India ----------------------------------------------------------------------***---------------------------------------------------------------------
Abstract - Geotechnical investigation and stability
designed with adequate safety margins, minimizing the risk of failure and ensuring the longevity of the roadway. The stability of such slopes depends on several factors including soil and rock properties, groundwater conditions, slope geometry, rainfall patterns, and the method of excavation. Improper design or lack of adequate investigation can lead to slope failures, which may result in traffic disruptions, loss of life, and economic damage. This study, titled “Geotechnical Investigation and Stability Evaluation of Cut Slopes in Highway Projects – Himachal Hilly Highway Section,” aims to analyze the geotechnical characteristics of the soil and rock along selected cut slopes, assess their stability under different conditions, and recommend suitable stabilization techniques to enhance safety and performance.
evaluation of cut slopes are essential components in the design and construction of highway projects, especially in hilly and mountainous terrains. The stability of cut slopes significantly influences the safety, durability, and serviceability of the roadway infrastructure. Field investigations, including borehole drilling, standard penetration tests (SPT), and collection of disturbed and undisturbed soil samples, were conducted to determine the subsurface conditions. Laboratory tests such as grain size analysis, Atterberg limits, direct shear test, and triaxial compression test were performed to evaluate shear strength parameters—cohesion (c) and angle of internal friction (φ). These parameters were used to analyze slope stability using limit equilibrium methods and numerical modeling techniques. Factors such as rainfall infiltration, groundwater conditions, and slope geometry were also considered in the analysis. The results indicate that slopes composed of highly weathered materials or loose soil deposits show reduced stability under saturated conditions. To enhance slope performance, suitable stabilization measures such as retaining structures, drainage provisions, and vegetation cover are recommended. The study highlights the importance of integrating geotechnical investigation data with stability analysis for effective slope design and risk mitigation in highway projects. Overall, this investigation provides a comprehensive approach to ensure safe and economical design of cut slopes, thereby minimizing the risk of landslides and ensuring sustainable transportation development in hilly areas.
The main objectives of this geotechnical investigation and slope stability evaluation are as follows: 1.To perform detailed field investigations including collection of disturbed and undisturbed soil and rock samples from selected cut slopes. 2. To determine engineering and index properties of the soil and rock materials through laboratory testing. 3. To assess the existing stability condition of cut slopes using analytical and numerical methods under both dry and saturated conditions. 4. To identify potential failure mechanisms affecting the slopes in the study area. 5. To propose suitable remedial and stabilization measures such as retaining structures, soil nailing, drainage improvement, or vegetation cover. 6. To prepare geotechnical design recommendations for safer and more stable highway cut slopes in hilly terrains.
1. INTRODUCTION Highway construction in hilly and mountainous regions presents unique engineering challenges due to the complex geology, steep topography, and variable climatic conditions. The process of cutting slopes to construct roadways often disturbs the natural equilibrium of the terrain, leading to potential slope instability, landslides, and erosion problems. In states like Himachal Pradesh, where the terrain is highly undulating and the geological conditions are heterogeneous, the issue of slope stability becomes a critical factor in the design, construction, and maintenance of highway. Geotechnical investigation plays a crucial role in understanding the subsurface conditions and evaluating the stability of slopes along highway alignments. Proper geotechnical assessment ensures that the slopes are
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2. LITERATURE REVIEW The stability of slopes, especially in hilly and mountainous terrains, has been one of the major concerns for geotechnical engineers and highway designers. The increasing demand for road infrastructure in such regions often necessitates cutting natural slopes, which disturbs the in-situ stress conditions and frequently leads to slope failures or landslides. The purpose of this literature review is to summarize the previous research and existing knowledge related to the geotechnical investigation, analysis, and
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