基于响应面法的PP-PAM复合改良微生物固化膨胀土优化研究  

Optimization study of PP-PAM composite modified microbial solidified expansive soil based on response surface method

作　　者：张银峰 赵卫全[2] 陈筠 耿会岭 杨涛[3] 齐少烽 ZHANG Yinfeng;ZHAO Weiquan;CHEN Jun;GENG Huiling;YANG Tao;QI Shaofeng(Geological Museum of Guizhou,Guiyang 550081,Guizhou,China;China Institute of Water Resources and Hydropower Research,Beijing 100038,China;Guizhou Institute of Technology,Guiyang 550003,Guizhou,China)

机构地区：[1]贵州省地质博物馆,贵州贵阳550081 [2]中国水利水电科学研究院,北京100038 [3]贵州理工学院,贵州贵阳550003

出　　处：《水利水电技术（中英文）》2024年第3期173-183,共11页Water Resources and Hydropower Engineering

基　　金：国家重点研发计划课题(2019YFC1509800);安徽省引江济淮工程科技创新项目(YJJH-ZT-ZX-20221130515);中国水科院科研专项(EM0145B182020)。

摘　　要：【目的】采用微生物诱导碳酸钙沉淀技术(MICP)加固膨胀土,可有效提高膨胀土的强度,降低胀缩性,但存在土体破坏时脆性明显,以及养护初期崩解量高等问题,为了进一步改善微生物固化膨胀土的脆性破坏和养护初期崩解量高的问题,【方法】在微生物固化膨胀土的基础上,研究掺入聚丙烯纤维(PP)和聚丙烯酰胺(PAM)对微生物固化膨胀土破坏模式和水稳性的影响。以纤维长度、纤维掺量和聚丙烯酰胺掺量为影响因素,以无侧限抗压强度和崩解量为响应值,采用Box-Behnken响应面法进行条件优化试验,建立了响应面回归模型,获得聚丙烯纤维长度、聚丙烯纤维和聚丙烯酰胺用量及其交互作用对微生物固化膨胀土强度和崩解性综合指标的影响。【结果】结果表明:聚丙烯纤维的掺入降低了微生物固化膨胀土破坏时的脆性、提高了土体强度、降低了膨胀土的崩解性,但随着纤维长度的增加,崩解量逐渐增加;聚丙烯酰胺的掺入降低了膨胀土的崩解量,但会降低土体强度。【结论】在影响因素试验范围内,以无侧限抗压强度最高和崩解量最低为原则,通过Box-Behnken响应面法获得最佳配比为:聚丙烯纤维长度为9 mm,掺量为0.5%,聚丙烯酰胺掺量为0.12%。在此配比下,复合固化土的无侧限抗压强度为1.24 MPa,相比优化前提高了29.57%,崩解量仅为0.34%,相比优化前降低了99.07%。[Objective]The microbial-induced calcium carbonate precipitation technology(MICP)can effectively improve the strength of expansive soil,as well as reduce the expansion and shrinkage of expansive soil,however,there are some problems such as obvious brittleness,and high disintegration during the early curing period.In order to further improve the brittle failure of microbial solidified expansive soil and the high amount of disintegration in the early stage of conservation,[Methods]In this study,the effects of adding polypropylene fiber(PP)and polyacrylamide(PAM)on the failure mode and water stability of microbial solidified expansive soil were studied on the basis of microbial solidified expansive soil.With the fiber length,fiber content,and polyacrylamide content as the influencing factors,and with the unconfined compressive strength and disintegration amount as the response values,the Box-Behnken Design response surface method was used to conduct the condition optimization test,based on the above research a response surface regression model was established.The effects of the length of polypropylene fiber,the amount of polypropylene fiber,polyacrylamide,and their interaction on the comprehensive indexes of strength and disintegration of microbe-cured expansive soil were studied.[Results]The result show that the addition of polypropylene fiber reduces the brittleness when the microbial curing and expanded soil is destroyed,improves the strength of the soil,and reduces the disintegration of the expanded soil.However,with the increase of fiber length,the disintegration amount increases gradually;the addition of polyacrylamide reduces the disintegration of expansive soil but decreases the soil strength.[Conclusion]In the test range of influencing factors,the highest unconfined compressive strength and the lowest disintegration amount were taken as the principle,and the optimal ratio was obtained by Box-Behnken response surface method:the length of polypropylene fiber was 9 mm,the content was 0.5%,and the content of po

关 键 词：微生物诱导碳酸钙沉淀 膨胀土改良 响应面法 优化试验 聚丙烯纤维 聚丙烯酰胺 变形 影响因素 

分 类 号：TU442[建筑科学—岩土工程]