Geotechnical Evaluation and Foundation Scheme Research for Soft Soil Foundation Engineering Reconstruction and Expansion Project in Guangzhou Urban Area

Abstract

To address core geotechnical challenges in reconstruction projects within soft soil areas of the Pearl River Delta, this study employs the Guangzhou Urban Area Campus A Basketball Court Expansion Project as a case study. Through integrated survey methods combining drilling, in-situ testing, and laboratory experiments, we systematically investigated the site's engineering geological conditions, mechanical properties of soil layers, groundwater distribution patterns, and types of adverse geological phenomena. The findings reveal that the site represents a typical alluvial-originated non-uniform foundation in the Pearl River Delta, consisting of artificial fill layers, flow-plastic to soft plastic silt layers, loose fine sand layers, and weathered chalky siltstone formations. The silt layers exhibit high compressibility and low strength characteristics, while the fine sand layers demonstrate severe liquefaction potential. Considering a seismic fortification intensity of 7 degrees, the site is classified as structurally vulnerable for buildings. Geological assessments indicate that groundwater poses minimal corrosion risks to concrete structures, while overground soil layers exhibit moderate corrosive effects. Although the site demonstrates good geological stability suitable for construction, critical mitigation measures are required to prevent soft soil subsidence, sand liquefaction, uneven settlement, and pile foundation-induced disturbances to existing structures. The study recommends rotary drilling/boring cast-in-place piles as the primary foundation method, proposes targeted mitigation strategies, and provides technical references for similar soft soil reconstruction projects in Guangzhou urban areas.