冻融循环作用下节理岩体锚固性能退化机理和模式

Mechanism and Style of Anchorage Degradation in Jointed Rock Mass Under Cycle of Freezing and Thawing

岩土锚固的长期性能和耐久性是当前岩土工程界普遍关注的热点问题,也是影响锚固工程长期安全性的关键问题之一。节理岩体存在不同尺度、程度的损伤和缺陷,为地下水的存储和运移提供场所和通道。当达到孔隙水和裂隙水的冻结温度时,岩体中产生冻胀,并伴随着水分迁移,影响锚固系统的锚固性能,在冻融循环作用下,引起锚固系统长期性能和耐久性的退化。依据孔隙介质的冻结理论,建立了砂浆、岩石、砂浆-钢筋和砂浆岩石接触面静水压力学模型,分析其冻结机理。在总结岩石冻融损伤劣化研究成果基础上,深入系统地分析了节理岩体锚固系统的冻融损伤劣化机理及其影响因素,并建立冻融循环作用下节理岩体锚固性能退化的6种模式及其数学模型。

The durability and long-term strength of anchor are the key factors to influence the safety of ground anchorages,therefore it is one of hot research problems in geotechnical engineering.The different scale and degree of damages and defects in jointed rock mass provide a storage space and transporting channels for groundwater in rocks.The frost heaving and accompanied by groundwater migration caused by freezing in rocks will affect the anchorage system performance.freezing and thawing cycles will result in degradation of long-term anchoring performance and durability of anchorage system.Therefore based on the freezing theory of porous media,a hydrostatic pressure model on contact surfaces among mortar,rocks,mortar-steel and mortar-rock is constructed after analyzing the freezing mechanism.The damage mechanism due to freezing and thawing and its influence factors are studied more systematically.Considering the existing relevant achievements six modes and their corresponding mathmetical models are established to describe the degradation of anchorage performance in jointed rocks under repeating freezing and thawing.