胶凝风化料配合比三轴试验颗粒流细观模拟  

Mesoscale simulation study on triaxial test of cementitious weathered material mix proportion based on PFC

作　　者：王能龙 徐兴倩 肖思友 赵熹 曹涵 王海军 WANG Nenglong;XU Xingqian;XIAO Siyou;ZHAO Xi;CAO Han;WANG Haijun(College of Water Conservancy,Yunnan Agricultural University,Kunming 650000,China;School of Civil engineering and Urban Planing,Liupanshui Normal University,Liupanshui 553004,China)

机构地区：[1]云南农业大学水利学院,云南昆明650000 [2]六盘水师范学院土木与规划学院,贵州六盘水553004

出　　处：《铁道科学与工程学报》2024年第9期3622-3635,共14页Journal of Railway Science and Engineering

基　　金：国家自然科学基金资助项目(42367025);贵州省基础研究计划项目(黔科合基础-ZK[2022]一般533);云南省高层次人才培养支持计划“青年拔尖人才”专项(YNWR-QNBJ-2020-030)。

摘　　要：胶凝砂砾石料筑坝具有就地取材方便、经济环保及施工快速等优势,但胶凝风化料配合比较难确定,室内试验存在取样难、测试周期长及耗费高等问题,智能算法未考虑材料颗粒特征及矿物成分影响且需要大量训练样本。为了探索颗粒流法应用于胶凝风化料配合比设计的可行性,采用PFC3D颗粒流对不同水泥、粉煤灰和风化料掺量的胶凝材料进行三轴数值模拟分析,探讨不同配合比胶凝风化料抗剪性能及变形破坏特征,最终获取胶凝风化料的最佳配合比。研究结果表明:1)在相同围压和粉煤灰掺量条件下,随着水泥掺量逐渐增加,胶凝风化料峰值应力逐渐增大,但对于相同水泥掺量,粉煤灰占比较小有利于提高胶凝风化料抗剪强度,反之粉煤灰占比增加则会削弱胶凝风化料的抗剪强度;2)胶凝风化料中粉煤灰和水泥掺量对其剪切特性影响较大,在两者掺量合理占比范围内,随水泥、粉煤灰掺量增加,胶凝风化料在变形破坏机理上表现为剪切破坏位移减小,抗转动能力增强,黏结颗粒量增加,进而有效地提高了胶凝风化料的抗剪强度;3)基于数值模拟得到胶凝风化料三轴模拟最佳配合比为水泥∶粉煤灰∶风化料=1∶0.95∶18.38,以该配比制备试样开展室内大三轴测试验证,发现胶凝风化料抗剪强度模拟值与试验值相对误差较小。通过颗粒流法模拟不同配比胶凝风化料抗剪特性具有较好的适用性,能有效提高胶凝风化料的配合比设计效率。The construction of cemented sand and gravel dam has the advantages of convenient local raw materials,economic-environmental protection and rapid construction.However,it is difficult to determine the mix ratio of cementitious weathered materials.The indoor test has the problems of difficult sampling,long test period and high cost.The intelligent algorithm does not consider the influence of material particle characteristics and mineral composition,and a large number of training samples need to be given.To further explore the feasibility of applying particle flow method to the mix ratio design of cementitious weathered materials.PFC3D particle flow was used to simulate triaxial tests on cementitious materials with different cement,fly ash and weathered material contents.The shear resistance and deformation failure characteristics of cementitious weathered materials with different mix ratios were discussed to obtain the best mix ratio finally.The research results are showed as follows.(1)The peak stress of cementitious weathering material increases gradually with the increasing cement content under the same confining pressure and fly ash content.Meanwhile,the small proportion of fly ash is beneficial to improve the shear strength of cementitious weathering material for the same cement content.The increasing fly ash proportion can conversely weaken the shear performance of cementitious weathering material.(2)The content of fly ash and cement has a great influence on its shear characteristics.Within the reasonable proportion of the two contents,the deformation and failure mechanism can show that the shear failure displacement decreased,the anti-rotation ability and the amount of bonded particles increases with the increasing content of cement and fly ash,so the shear strength of the cementitious weathering material is effectively improved.(3)The optimum mix ratio of cementitious weathering material from the triaxial simulation is cement∶fly ash∶weathering material=1∶0.95∶18.38,and this ration is verified by th

关 键 词：胶凝风化料 PFC3D 三轴模拟 配合比 细观结构 抗剪强度 

分 类 号：TU411.92[建筑科学—岩土工程]