宁波大桥主墩墩址软弱带成因机制研究

通过对宁波大桥主墩墩址软弱带详细的地质勘测和综合方法研究，内中包括粘土泥质物Ｘ射线衍射分析，软弱带岩石化学成分和不同成因砂和砾石的成分和特征研究，特别是软弱带的显微构造和物质来源的研究，本文对这一软弱带的成因机制着重进行了探讨。研究发现，这一软弱带在结构上可划分为三部分或三层结构，下部为挤压破碎带、中部为风化产物、上部为地表水贯入充填堆积。它表明这一软弱带经历了三种不同的地质作用的演化过程或具有三种物质来源。这一研究结论对大桥的设计和施工有重要的影响和意义。

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.