含水状态对硅质胶结砂岩抗拉特性的影响及颗粒流模拟  

Influence of Water-bearing State on Tensile Properties of Siliceous Cemented Sandstone and Particle Flow Simulation

作　　者：朱作祥 骆祚森 李建林[1,2] 邓华锋[1,2] 王乐华[1,2] ZHU Zuoxiang;LUO Zuosen;LI Jianlin;DENG Huafeng;WANG Lehua(Key Laboratory of Geological Hazards on Three Gorges Reservoir Area(China Three Gorges University),Ministry of Education,Yichang 443002,Hubei,China;College of Civil Engineering&Architecture,China Three Gorges University,Yichang 443002,Hubei,China)

机构地区：[1]三峡库区地质灾害教育部重点实验室(三峡大学),湖北宜昌443002 [2]三峡大学土木与建筑学院,湖北宜昌443002

出　　处：《材料导报》2025年第9期84-92,共9页Materials Reports

基　　金：国家自然科学基金(U22A20600,U2034203)。

摘　　要：为探究含水砂岩胶结微细观结构特征变化与抗拉特性的关系和影响机制,以三峡库区常见的硅质胶结砂岩为研究对象,开展不同含水状态下砂岩的巴西劈裂试验及微细观结构测试;基于室内试验结果,提出含水砂岩胶结软化的颗粒流数值模拟方法,开展砂岩劈裂数值模拟分析。结果表明:(1)含水状态对砂岩的抗拉强度和破坏特征均会产生影响。从干燥到饱水状态,砂岩抗拉强度下降了49.93%,破坏形态由沿中线笔直断裂向沿中线弧状弯曲断裂转变。(2)微细观测试结果发现,随含水率增大,砂岩劈裂断面的穿颗粒断裂破坏形式逐渐减少,转化为穿颗粒断裂与沿颗粒断裂复合破坏形式,很好地解释了砂岩宏观破坏特征随含水率的变化规律。(3)试验砂岩胶结物中存在增生型和沉淀型两种硅质胶结物,增生型胶结基本不受含水状态的影响,而沉淀型胶结易遇水软化,是砂岩抗拉强度随含水率变化的重要原因。(4)PFC^(3D)模拟发现,随沉淀型胶结软化程度的增加,试样裂纹起裂点逐渐提前,沉淀型胶结断裂逐渐取代增生型胶结断裂,最大接触力不断减小,抗拉强度呈降低趋势。To explore the relationship and influence mechanism between the change of microstructure characteristics and tensile properties of water-bea-ring sandstone cementation,the Brazilian splitting test and microstructure test were carried out to siliceous cemented sandstone under diffe-rent water-bearing conditions in the Three Gorges Reservoir area.Based on the indoor test results,a particle flow numerical simulation method for cementation softening of water-bearing sandstone was proposed to fulfil the sandstone splitting simulation analysis.The results show that:(1)The water-bearing state affects the tensile strength and failure characteristics of sandstone.From dry to saturated state,sandstone tensile strength decreased by 49.93%,and the failure mode changed from straight fracture along the midline to curved fracture along the midline.(2)The microscopic test results show that with the increase of water content,the failure mode of transgranular fracture of sandstone splitting section gradually decreases,and it is transformed into the composite failure mode of transgranular fracture and intergranular fracture,which well explains the variation in macroscopic failure characteristics of sandstone with water content.(3)There are two kinds of siliceous cements in the tested sandstone cements,namely,the proliferative type and the precipitated type.The proliferative type is generally not affected by water content,while the precipitated type is easily softened by water.This is a major reason for the change in the tensile strength of sandstone with water content.(4)PFC^(3D) simulation results show that with the increase of the softening degree of precipitated cementation,the crack initiation point of the sample gradually advances,the precipitated cementation fracture gradually replaces the proliferative cementation fracture,and the maximum cementation contact force decreases continuously,then the final tensile strength shows a decreasing trend.

关 键 词：岩石力学 巴西劈裂试验 含水率 砂岩 微细观结构 离散元法 

分 类 号：TU451[建筑科学—岩土工程]