摘要
2017年九寨沟“8·8”地震导致火花海钙华坝受损,而针对自然遗产地的加固材料须为生态环保材料,研发的糯米灰浆采用支链淀粉团聚石灰、石膏与硅粉,达到了加固钙华坝的目的。为满足九寨沟钙华地区坝体加固对注浆材料的要求,在传统糯米灰浆中加入外加剂、硅灰、石膏改善其流变性与力学性能。改变糯米灰浆中石灰/石膏质量比(0、0.11、0.25、0.43、0.67),通过常规剪切(0.01~100 s^(-1))与循环剪切(0.01~300 s^(-1))测定流变曲线,分析改性糯米灰浆的流变性与触变性。此外,对改性糯米灰浆结石体的力学特性进行研究,并利用扫描电子显微镜分析结石体的微观结构。结果表明:石灰/石膏质量比由0变化到0.67,浆液最大黏度降低了84.7%~91.3%,其对应剪切速率逐渐增大;改性糯米灰浆属于带屈服值的假塑性流体材料;与Bingham模型相比,Herschel-Bulkley模型能更好地描述改性糯米灰浆的流变性;改性糯米灰浆具有触变性,石灰组份的掺入导致浆液的触变性降低,与黏度受影响规律相仿;触变性受剪切历史控制,呈现出随剪切循环次数的增大而降低的特点;改性糯米灰浆结石体28 d的抗压强度可达9.78 MPa;随着石灰/石膏质量比的增大,改性糯米灰浆结石体的弹性模量逐渐减小,宏观破裂方式由脆性破坏过渡到延性破坏。
In 2017,an earthquake struck the Jiuzhaigou Valley,causing the collapse of the Huohua(“spark”)Lake dam.The reinforcement materials for natural heritage sites must be ecological and environmentally friendly.The sticky rice mortar developed is made of amylopectin-agglomerated lime,gypsum,and silica powder,which achieved the purpose of strengthening the travertine dam.In this paper,additives,silica fume,and gypsum were added to traditional sticky rice mortar to improve its rheological properties and mechanical properties.The mass ratio of lime to gypsum in modified sticky rice mortar was changed(0,0.11,0.25,0.43,0.67).The rheological curves of modified sticky rice mortar were measured by conventional shear(0.01~100--s^(-1))and cyclic shear(0.01~1300--s^(-1)).The rheological properties and thixotropy of modified sticky rice mortar were analyzed.In addition,the mechanical properties of modified sticky rice mortar stone body were studied,and the microstructure of the modified sticky rice mortar stone body was studied by SEM.The result shows that the maximum viscosity of mortar decreases by 84.7%~91.3%while lime/gypsum mass ratios change from 0 to 0.67,and the corresponding shear rate increased gradually.Modified sticky rice mortar is a pseudoplastic fluid material with yield value.Compared with the Bingham model,the Herschel-Bulkley model can better describe the rheological properties of modified sticky rice mortar.Modified sticky rice mortar has thixotropy,and the addition of lime leads to the decrease of the thixotropy of mortar,which is similar to the effect of viscosity.The thixotropy is controlled by shear history and decreases with the increase of the number of shear cycles.The mechanical properties can be illustrated as follows.The compressive strength of modified sticky rice mortar stone can reach 9.78--MPa after 28--d.With the increase of lime/gypsum mass ratios,the elastic modulus of the modified sticky rice mortar stone decreases gradually,making the macroscopic fracture mode transition from brittle fail
作者
王文俊
裴向军
周立宏
杜杰
张济宁
黄琪卓
WANG Wenjun;PEI Xiangjun;ZHOU Lihong;DU Jie;ZHANG Jining;HUANG Qizhuo(State Key Laboratory of Geohazard Prevention and Geoenvironment Protection,Chengdu 610059,China;Jiuzhaigou National Nature Reserve Administration,Jiuzhaigou 623407,China)
出处
《工程地质学报》
CSCD
北大核心
2024年第1期303-314,共12页
Journal of Engineering Geology
基金
国家自然科学基金重大项目(资助号:41790445)
四川省灾后重建遗产保护恢复专项(资助号:5132202019000128)。
关键词
改性糯米灰浆
注浆材料
流变性
触变性
力学性能
Modified sticky rice mortar
Grouting material
Rheology properties
Thixotropy
Mechanical property
