A Comparative Framework for Foundation Selection in Saturated Tropical High-Plasticity Clays: Optimization of Mass Housing Infrastructure

Constructing heavy infrastructure on high-plasticity tropical clays presents significant challenges regarding total and differential settlement. This research compares the performance of shallow foundations (spread and raft) against bored cast-in-situ piles in the "fat clay" (CH) deposits of Sonfonia, Guinea. Using Terzaghi and Peck’s method for elastic settlement and Meyerhof’s bearing capacity theory, the study demonstrates that under permanent submerged conditions, settlement exceeds 130mm for shallow footings, rendering them unfeasible for multi-story structures. A proposed foundation solution of using raft or pile systems is analyzed, showing a significant reduction in serviceability-limit movements. The paper provides a decision-making framework for selecting foundation types in saturated, settlement-sensitive tropical soil profiles.