红层软岩遇水崩解特性试验及其界面模型  

Experimental study of disintegration characteristics of red-bed soft rock within water and its interface model

作　　者：潘艺[1,2] 刘镇 周翠英 

机构地区：[1]中山大学工学院,广东广州510275 [2]广东省重大基础设施安全工程技术研究中心,广东广州510275 [3]中山大学土木工程学院,广东广州510275

出　　处：《岩土力学》2017年第11期3231-3239,共9页Rock and Soil Mechanics

基　　金：国家自然科学基金重点项目(No.41530638);国家自然科学基金科学仪器基础研究专项(No.41227002);国家自然科学基金面上项目(No.41372302;No.41472257);国家重点研发计划专项项目(No.SQ2017YFSF060085)~~

摘　　要：红层软岩遇水崩解是引发工程灾害的重要原因。红层软岩遇水崩解缘于水作用下软岩细观成分组构的变化,但目前软岩崩解特性定量表征研究多根据宏观现象,所得到的崩解模型难以对软岩崩解的细观过程进行研究。根据室内软岩静态崩解和软岩碎片浸水试验以及不同浸泡阶段的软岩的成分组构扫描电镜观察试验,揭示了水-软岩界面的细观演化规律:红层软岩的崩解机制缘于软岩碎片间泥质填充区中水-岩界面上的黏土颗粒在水作用下发生水化、扩散和流失致使泥质胶结带缩减,从而引起碎片间凝聚力下降;静水作用下软岩碎片间的凝聚力随时间呈幂函数衰减。在此基础上,利用界面与胶体化学、断裂力学理论,定量表征了软岩中水化黏土颗粒的流失以及软岩碎片间的模式Ⅱ型开裂,建立了软岩遇水崩解的界面模型,进而定量表征了软岩遇水崩解过程。通过对比计算,利用上述所建模型计算的软岩碎片剥落时间和试验观察的软岩碎片剥落时间相近,从而验证了模型的合理性。Disintegration of soft rock within water is considered as a fatal factor causing the engineering disasters. It is widely accepted that the disintegration results of soft rock from the variation of the microstructure of soft rock within the water. However, only a few studies were carried out to quantitatively describe soft rock disintegration, based on its meso-mechanism. We conducted experiments on the static disintegration of soft rock and immersion tests of soft rock debris in the laboratory. Besides, the compositions of soft rock at different soaking stages were analyzed by scanning electron microscopic as well. Finally, this study revealed the microscopic evolution of the interface between water and soft rock, according to the obtained results. The disintegration mechanism of the red-layer soft rock was generally caused by the hydration, diffusion and loss of clay particles in the water-rock interface in the mud-filled area of the soft rock fragments. Then the related shale cementation was reduced, resulting in the decrease of cohesion between debris. The cohesion between fragments of soft rock decreased exponentially with time under hydrostatic action. On the basis of the above analysis, the loss of hydrated clay particles in soft rock and the cracking type of model Ⅱ between soft rock fragments were quantitatively identified by using the interface and colloid chemistry and fracture mechanics theory. The interfacial model of soft rock with water disintegration was established, and the disintegration process of soft rock was further demonstrated quantitatively. By comparing the obtained results, the flaking time of soft rock fragments calculated by the above model was similar to that observed in the experiment, which verified the rationality of the model.

关 键 词：红层软岩 崩解特性 水-岩作用 界面模型 

分 类 号：TU45[建筑科学—岩土工程]