干湿循环作用下微生物改良花岗岩残积土劣化规律研究  

Study on the deterioration law of microbial improved granite residual soil under dry-wet cycle

作　　者：朱文羲 邓华锋[1,2] 李建林[1,2] 马林建 李锦瑞 陈勇琪 陈向阳 ZHU Wenxi;DENG Huafeng;LI Jianlin;MA Linjian;LI Jinrui;CHEN Yongqi;CHEN Xiangyang(Key Laboratory of Geological Hazards on Three Gorges Reservoir Area,Ministry of Education,China Three Gorges University,Yichang,Hubei 443002,China;College of Civil Engineering and Architecture,China Three Gorges University,Yichang,Hubei 443002,China;State Key Laboratory of Disaster Prevention and Mitigation of Explosion and Impact,Army Engineering University of PLA,Nanjing,Jiangsu 210007,China)

机构地区：[1]三峡大学三峡库区地质灾害教育部重点实验室,湖北宜昌443002 [2]三峡大学土木与建筑学院,湖北宜昌443002 [3]陆军工程大学爆炸冲击防灾减灾全国重点实验室,江苏南京210007

出　　处：《岩石力学与工程学报》2025年第2期482-491,共10页Chinese Journal of Rock Mechanics and Engineering

基　　金：国家自然科学基金资助项目(U22A20600,U2034203);三峡大学三峡库区地质灾害教育部重点实验室开放基金项目(2023KDZ15)~~。

摘　　要：采用微生物诱导碳酸钙沉淀技术(MICP)对岩土体进行改良是当前的研究热点,而针对改良后土体抵抗干湿循环作用能力的研究以及劣化机制的分析鲜有报道。因此,以微生物改良后的花岗岩残积土为研究对象,结合典型环境因素设计干湿循环试验,综合力学试验和微细观检测,系统分析微生物改良后花岗岩残积土在干湿循环作用下力学性能变化及劣化机制。结果表明:(1)干湿循环作用下,改良土的抗压强度、抗剪强度呈先快后慢的劣化趋势,30期干湿循环作用后,抗压强度,黏聚力,内摩擦角分别降低56.73%,38.73%,24.66%,其中,前12个周期的劣化速度较快,而后劣化速度明显降低并逐渐趋于稳定。(2)在干湿循环作用下,由于碳酸钙胶结物和长石矿物的溶解作用影响,改良土的孔隙率、密度、纵波波速呈现与力学参数一致的变化规律。(3)微细观结构显示,改良后花岗岩残积土的孔隙结构结构明显改善,密实性明显增强,联通的孔隙明显减少,干湿循环作用下,部分联通孔隙处的碳酸钙胶结物和长石矿物发生溶解,导致孔隙率呈一定的增大趋势,但碳酸钙胶结形成封闭孔隙处的碳酸钙依然保持完整的性态,同时,长石溶解生成的高岭石与钙离子反应生成硅铝酸盐沉淀对孔隙通道形成填充和堵塞,进而使得改良体在干湿循环作用下的微细观结构变化和物理力学性能劣化也趋于稳定。相关研究思路和结果可为MICP技术在花岗岩残积土改良中的应用提供参考。The application of Microbially Induced Calcite Precipitation(MICP)technology to improve geomaterials has become a significant research focus. However,studies on the resistance of treated soils to wet-dry cycles andthe analysis of their deterioration mechanisms are still limited. Therefore,this study focuses on granite residual soiltreated with microbial improvement and designs wet-dry cycle tests under typical environmental conditions.Comprehensive mechanical tests and microstructural analysis were conducted to systematically analyze the changesin mechanical properties and deterioration mechanisms of the microbially improved granite residual soil under wetdrycycling. The results indicate that:(1) under the influence of wet-dry cycles,the compressive strength and shearstrength of the treated soil exhibit a deterioration trend that is initially rapid but gradually slows down. After 30cycles,the compressive strength,cohesion,and internal friction angle decrease by 56.73%,38.73%,and 24.66%,respectively. The deterioration is faster during the first 12 cycles,while it significantly slows and stabilizesthereafter. (2) The porosity,density,and P-wave velocity of the treated soil exhibit a change pattern consistent withthe mechanical parameters due to the dissolution of calcium carbonate cement and feldspar minerals under wet-drycycles. (3) Microstructural analysis reveals significant improvements in the pore structure of the treated graniteresidual soil,with increased compaction and a marked reduction in interconnected pores. During wet-dry cycles,the dissolution of calcium carbonate cement and feldspar minerals in some interconnected pores leads to a slightincrease in porosity. However,the calcium carbonate within enclosed pores remains intact,and the kaoliniteproduced from feldspar dissolution reacts with calcium ions to form aluminosilicate precipitates that fill and blockpore channels. Consequently,the microstructural changes and the deterioration of the physical and mechanicalproperties of the treated soil under wet

关 键 词：土力学 干湿循环 花岗岩残积土 MICP 劣化机制 

分 类 号：TU43[建筑科学—岩土工程]