冻融循环对MICP加固土性能的影响  

Effect of freeze-thaw cycles on the properties of MICP-treated soil

作　　者：李俊[1] 张伟丽[1] 陈宗武 李明依 LI Jun;ZHANG Weili;CHEN Zongwu;LI Mingyi(Faculty of Engineering,China University of Geosciences(Wuhan),Wuhan 430074,China;State Key Laboratory of Green Building Materials,China General Research Institute of Building Materials Science Co.,Beijing 100024,China)

机构地区：[1]中国地质大学(武汉)工程学院,武汉430074 [2]中国建筑材料科学研究总院有限公司绿色建筑材料国家重点实验室,北京100024

出　　处：《地质科技通报》2025年第1期175-184,共10页Bulletin of Geological Science and Technology

基　　金：国家自然科学基金项目(51808517);绿色建筑材料国家重点实验室开放基金项目(2021GBM03);中国地质大学(武汉)教学实验室开放基金项目(SKJ2022073)。

摘　　要：近年来微生物诱导碳酸钙沉积技术(MICP)备受关注,在土体加固领域也取得了一定进展。微生物加固后土体性能整体得到提升,但是冬冻春融的循环作用,使得土体结构逐渐松散,导致土体强度、抗冲刷性和保水能力均有所降低。目前针对冻融循环对MICP固化土性能影响研究较少。采用喷洒法对试样表面进行了MICP固化处理,对多组试样给予不同冻融周期作用,并进行了无侧限抗压强度测试、冲刷试验和水分蒸发试验,探讨了试样水分蒸发速率随冻融周期增加的变化规律,以及冻融对加固土性能的影响。基于土体抵抗冲刷破坏作用机理,结合不同冻融周期下试样的表观松散程度和试验结果,探究了冻融循环导致加固土性能下降的原因。试验结果表明:试样无侧限抗压强度(UCS值)从43.83 kPa提高到加固后的69.92 kPa,经历20次冻融循环,加固试样的UCS值为未加固试样1.48倍,且加固试样冲刷侵蚀量远小于未加固试样的一半。研究表明微生物诱导生成的碳酸钙沉积物能够有效填充土体内部孔隙,黏结松散土颗粒,从而大幅提高土体强度,有效削弱冻融对土体的破坏作用。虽然冻融循环作用周期增加使得土体的加固效果逐渐劣化,但在短期冻融环境下,MICP加固后土体仍具有较高的强度,并能有效抵抗雨水的冲刷侵蚀作用。[Objective]The microbial induced carbonate precipitation(MICP)technology has received widespread attention from the academic community and has also made certain progress in the field of soil reinforcement.After MICP,the overall performance of the soil is improved,but the cyclic effect of winter freezing and spring thawing gradually loosens the soil structure,resulting in a decrease in soil strength,erosion resistance,and water retention capacity.Currently,there is limited research on the impact of freeze-thaw cycles on the properties of MICP stabilized soil.[Methods]This study investigated the effects of freeze-thaw cycles on the unconfined compressive strength(UCS),erosion resistance,and water retention capacity of soil treated with MICP under different conditions.The surfaces of the samples were treated via the spray method,and then,some samples were subjected to erosion tests.The UCS and water evaporation rate of the samples under different numbers of freeze-thaw cycles were tested.Combining the mechanism of soil resistance to erosion damage and the test results of samples subjected to freezethaw cycles,the reasons for the deterioration of reinforced soil properties due to freeze-thaw cycles were investigated.[Results]The results revealed that the UCS of the sample increased from 43.83 kPa to 69.92 kPa after MICP treatment.After 20 freeze-thaw cycles,the UCS value of the MICP-treated sample was 1.48 times greater than that of the uncured sample,and the erosion amount of the MICP-treated sample was much less than half of that of the uncured sample.Research has shown that microbial induced calcium carbonate deposits can effectively fill the internal pores of the soil and bind loose soil particles,significantly improving the soil strength and effectively weakening the destructive effect of freeze-thaw cycles on the soil.[Conclusion]Although the reinforcement effect of the soil gradually deteriorated due to the increase in the number of freeze-thaw cycles,the MICP-treated soil still had high strength in a short-te

关 键 词：微生物诱导碳酸钙沉积(MICP) 微生物加固土 冻融循环 雨水冲刷 

分 类 号：TU472.99[建筑科学—结构工程]