How do different soil types affect the stability and settlement of building foundations? Discuss the various factors civil engineers must consider when designing foundations for structures in cohesive soils, such as clay, and non$-$cohesive soils, like sand. Evaluate the challenges and strategies involved in mitigating settlement and ensuring structural stability in each soil type. Additionally, explore the role of geotechnical investigations and laboratory testing in assessing soil properties and informing foundation design decisions.