Q1: The angle of repose of a soil is the maximum angle which the outer face of the soil mass makes

ANS:A - with the horizontal

The angle of repose of a soil is a fundamental property used in geotechnical engineering to characterize the stability of loose, granular materials such as sand, gravel, and soil. It represents the steepest angle at which a pile of the material can remain stable without sliding or slumping. Understanding the angle of repose is crucial in various engineering applications, including the design of retaining walls, slopes, embankments, and foundations, as well as in analyzing the stability of natural and man-made slopes. The measurement of the angle of repose typically involves constructing a conical pile of the material on a flat surface or in a container. The material is poured or added gradually until the pile reaches a point where it begins to naturally form a stable slope. At this point, the angle between the horizontal plane and the slope of the pile is measured using a protractor or other measuring devices. This measured angle represents the angle of repose of the material. The angle of repose is influenced by several factors, including the particle size, shape, density, and moisture content of the material, as well as the internal friction between the particles. Generally, finer particles with smoother surfaces tend to have lower angles of repose compared to coarser, rougher particles. In engineering practice, the angle of repose is used to assess the stability of slopes and embankments. If the slope of a natural or man-made structure exceeds the angle of repose of the underlying soil or material, it is likely to experience instability and potential failure through mass movement processes such as landslides, slope failure, or collapse. Additionally, the angle of repose is utilized in the design of hopper bins, silos, and other storage systems to ensure proper material flow and prevent blockages or bridging. By understanding the angle of repose, engineers can design structures and systems that accommodate the natural behavior of granular materials, thereby enhancing safety and efficiency in various engineering applications.