THE GENETIC MECHANISM OF THE WEAK AND SOFT ZONE AT MAIN PIER SITE OF NINGBO BRIDGE

From the detailed field investigation and comprehensive study includING X─ray diffraction analysis of muddy materials,chemical composition study of the soft intercalation, composition and characteristics of different sand─gravel materials , especially the microscopic structure and material source of the weak and soft zone at main pier site of Ningbo Bridge, an emphasis is made on the problem of genetic mechanism of the zone.It is revealed that this zone is composed of three parts or layers in structure indicating three types of evolutional processes of the zone or material sources. The research has practical significance in bridge design and constructions.