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引用本文:罗丹虎,缴锡云,巫纾予,等.MICP加固土质排水沟边坡稳定性分析[J].灌溉排水学报,2024,43(5):71-78.
LUO Danhu,JIAO Xiyun,WU Shuyu,et al.MICP加固土质排水沟边坡稳定性分析[J].灌溉排水学报,2024,43(5):71-78.
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MICP加固土质排水沟边坡稳定性分析
罗丹虎,缴锡云,巫纾予,刘凯华,郭维华,李焕弟
河海大学 a.农业科学与工程学院,南京 211100;b.河海大学 水文水资源学院,南京 210098
摘要:
【目的】探究应用微生物诱导CaCO3沉淀(MICP)固结土壤技术对于土质排水沟边坡稳定性的影响机制。基于土工直剪试验和数值模拟法研究不同工况下MICP加固的土坡稳定性,为MICP生物护坡措施应用于土坡加固提供理论依据。【方法】选用OD600=0.97的巴氏芽孢杆菌和1 mol/L的固结液(CO(NH2)2∶CaCl2 =1∶1),固菌比为5∶3,添加15%固结液质量的脲酶抑制剂。布置4个试验土箱,设置对照组CK和固结组C1、C2、C3,对照组喷洒清水,设计入渗10 cm土层,固结组按先固结液后菌液顺序喷洒设计入渗5、10、15 cm土层。对固结后的风干土、饱和土、落干土进行直剪试验,利用直剪结果分析不同工况土坡稳定性。【结果】MICP处理的土体抗剪强度均有所提升;饱和处理后CK、C1、C2、C3的内摩擦角降幅为46.67%,39.73%,28.98%和27.85%,黏聚力降幅76.37%,62.83%,39.09%和51.62%,CK土坡处于欠稳定,C1、C2、C3土坡满足安全要求,黏聚力是影响边坡稳定的主要因素。【结论】MICP可以提高土质排水沟边坡的稳定性,其最佳固结深度是10 cm。
关键词:  MICP固结;土质边坡;固结深度;边坡稳定
DOI:10.13522/j.cnki.ggps.2023329
分类号:
基金项目:
Improving the stability of slopes of earth drainage ditches by microbially induced calcium carbonate precipitation
LUO Danhu, JIAO Xiyun, WU Shuyu, LIU Kaihua, GUO Weihua, LI Huandi
Hohai University a. College of Agricultural Science and Engineering, Nanjing 211100, China; b. College of Hydrology and Water Resources, Nanjing 210098, China
Abstract:
【Objective】Microbially induced calcium carbonate precipitation (MICP) is an eco-friendly and innovative technique for improving soil stability. This paper investigates the potential of MICP for improving the stability of slopes of earth drainage ditches.【Method】 Bacillus pasteurii with OD600=0.97 and consolidation solution with concentration of 1 mol/L (CO(NH2)2∶ CaCl2 = 1∶1) were used in the study. The solid - bacteria ratio was 5∶3, and a urease inhibitor at concentration of 15% was added to the consolidation solution. The experiment was conducted in boxes filled with soil. We sprayed the soil surface with the consolidation solution and the bacterial liquid alternatively for the infiltration to reach the depth of 5 cm (C1), 10 cm (C2) and 15 cm (C3), respectively. The control was to spray water over the soil surface. The mechanical properties of the soils were measured using direct shear tests when soils were air-dried, saturated, and naturally dried, respectively.【Result】The shear strength of the soils treated by MICP were all increased; the decrease of internal friction angle of CK, C1, C2, and C3 after saturation treatment were 46.67%, 39.73%, 28.98%, and 27.85%, and the decrease of cohesion were 76.37%, 62.83%, 39.09%, and 51.62%, the soil slope of CK was in the understability, and the slopes of C1, C2, and C3 met the safety requirements C1, C2 and C3 slopes meet the safety requirements, cohesion is the main factor affecting the stability of slopes.【Conclusion】Our findings suggest the optimal consolidation depth was 10 cm and demonstrate the efficacy of MICP for reinforcing the slopes of earth drainage ditches.
Key words:  MICP consolidation; soil slope; consolidation depth; slope stability