Soil failure occurs when the strength of soil is insufficient to support the loads placed upon it, leading to instability. This can happen due to various factors, including excessive moisture, erosion, or the weight of structures like buildings and bridges. When soil fails, it can result in landslides, sinkholes, or foundation problems. Preventing soil failure involves proper engineering practices, such as soil testing and drainage management. Techniques like retaining walls and geotextiles can help stabilize soil and reduce the risk of failure. Understanding soil properties is crucial for safe construction and land use.