南水北调中线工程上第三系膨胀性硬粘土的工程地质特性研究

上第三系硬粘土在中国东部新生代沉积盆地具有广泛的分布 ,因其性质复杂而成为中国区域性特殊岩土研究的重要对象。纵贯于南阳盆地和华北盆地西缘的南水北调中线工程长距离地开挖在不同的上第三系硬粘土中。本文在对南阳盆地、方城—宝丰、邯郸—永年三渠段上百个原状样的物质组成、物理性质、物化性质、膨胀性和收缩性、强度特性系统测试分析的基础上 ,总结了各类硬粘土的工程地质特性及其形成机理和变化规律 ,并根据不同湿度、围压状态下的试验结果分析了硬粘土的工程环境效应 ,这对于认识上第三系硬粘土在开挖运营条件下的变形破坏机理有着重要的理论和实际意义。

ENGINEERING GEOLOGICAL PROPERTIES OF NEOGENE HARD CLAY ALONG THE MIDDLE LINE OF THE NORTH-SOUTH DIVERSION WATER PROJECT IN CHINA

Neogene hard clay is widely distributed in the Cenozoic basins of east China, and is the main subject of regional studies of special sedimentary materials for its special properties. The middle line of the North-South Diversion Water Project lies across the west edge of Nanyang basin and the north China basin, excavating in various kinds of Neogene hard clay. Based on laboratory experiment and measurements, this paper presents the engineering geological properties of Neogene hard clay from the Nanyang basin, as well as Fangcheng Baofeng and Handan Yongnian regions, including the composition and physicochemical properties, physical properties shrink-swell characteristics, strength and other properties, and summarizes their formation mechanisms and variation laws. Meanwhile, the environmental effect under different humidity and lateral pressures is summarized, which is helpful to understand the deformation mechanism of Neogene hard clay under the condition of excavation and engineering operation.