该文通过一维固结压缩试验，研究基于微生物诱导碳酸钙沉积（MICP）技术拌和固化岛礁钙质砂，并改善其压缩特性。总结了完全不同于石英砂的钙质砂的压缩特性；固化试验研究中考虑了粒径级配、相对密度以及反应液浓度对钙质砂压缩特性的影响。试验结果表明：尽管拌和固化钙质砂所用菌液和反应液的用量很小，但是固化后的钙质砂的压缩特性仍有较大改善，压缩指数平均降低了约0.10；固结压缩曲线e-lgp呈现2或3个明显直线段；固化效果受土体粒径级配和相对密度的影响，高浓度反应液更有利于土体压缩性的降低。
Microbially induced carbonate precipitation (MICP) was used to treat calcareous sand to improve the compressive properties of the sand. Oedometer tests showed how the compressive properties of the calcareous sand differed from quartz sand. The tests evaluated the effects of the particle size gradation, the relative density and the reaction solution concentration on the compressive properties of the carbonate sands. The tests showed that small amounts of bacteria solution and reaction solution mixed with the calcareous sand greatly improved the compressive properties of the sand after solidification with the compression index reduced by about 0.10 on average and the e-lgp curve having 2 or 3 distinct straight segments. The particle size gradation and the relative density both affect the reinforced sample compressibility with high-concentration reaction solutions further reducing the calcareous sand compressibility.
[1] KHAN M N H, AMARAKOON G G N N, SHIMAZAKI S, et al. Coral sand solidification test based on microbially induced carbonate precipitation using ureolytic bacteria[J]. Materials Transactions, 2015, 56(10):1725-1732.
[2] 欧益希, 方祥位, 申春妮, 等. 颗粒粒径对微生物固化珊瑚砂的影响[J]. 水利与建筑工程学报, 2016, 14(2):35-39. OU Y X, FANG X W, SHEN C N, et al. Influence of particle sizes of coral sand on bio-cementation[J]. Journal of Water Resources and Architectural Engineering, 2016, 14(2):35-39. (in Chinese)
[3] 李捷, 方祥位, 申春妮, 等. 颗粒级配对珊瑚砂微生物固化影响研究[J]. 水利与建筑工程学报, 2016, 14(6):7-12. LI J, FANG X W, SHEN C N, et al. Influence of grain composition on coral sand bio-cementation[J]. Journal of Water Resources and Architectural Engineering, 2016, 14(6):7-12. (in Chinese)
[4] PIERRE L T, JEAN-FRANCOIS N. Foundations in carbonate soils[M]. Paris:Editions Technip, 1994.
[5] SEMPLE R M. Mechanical properties of carbonate soils[M]. JEWELL R J, ANDREWS D C. Engineering for calcareous sediments. Perth:Balkema, 1988.
[6] WILS L, VAN IMPE P, HAEGEMAN W. One-dimensional compression of a crushable sand in dry and wet conditions[C]//International Symposium on Geomechanics from Micro to Macro (TC 105 ISSMGE). London:Taylor and Francis Group, 2015:1403-1408.
[7] BRYANT W R, DEFLACHE A P, TRABANT P K. Consolidation of marine clays and carbonates[M]. INDERBITZEN A L. Deep-sea sediments, Marine science 2. Boston:Springer, 1974. DOI:10.1007/978-1-4684-2754-7_10.
[8] VALENT P J, ALTSCHAEFFL A G, LEE H J. Geotechnical properties of two calcareous oozes[M]. DEMARS K, CHANEY R. Geotechnical properties, behavior and performance of calcareous soils. West Conshohocken:ASTM International, 1982.
[9] CARTER J P, KAGGWA W S, JOHNSTON I W, et al. Triaxial testing of North Rankin calcarenite[M]. JEWELL R J, KHORSHID M S. Engineering for calcareous sediments. Rotterdam:Balkema, 1988.
[10] COOP M R. The mechanics of uncemented carbonate sands[J]. Geotechnique, 1990, 40(40):607-626.
[11] 张家铭, 汪稔, 石祥锋, 等. 侧限条件下钙质砂压缩和破碎特性试验研究[J]. 岩石力学与工程学报, 2005, 24(18):3327-3331. ZHANG J M, WANG R, SHI X F, et al. Compression and crushing behavior of calcareous sand under confined compression[J]. Chinese Journal of Rock Mechanics and Engineering, 2005, 24(18):3327-3331. (in Chinese)
[12] 毛炎炎, 雷学文, 孟庆山, 等.考虑颗粒破碎的钙质砂压缩特性试验研究[J]. 人民长江, 2017, 48(9):75-78. MAO Y Y, LEI X W, MENG Q S, et al. Compression feature of calcareous sand considering particle breakage[J]. Yangtze River, 2017, 48(9):75-78. (in Chinese)
[13] NAUROY J F, TIRANT P L. Model tests of piles in calcarecus sands[C]//Geotechnical Practice in Offshore Engineering. New York:ASCE, 1983:356-369.
[14] 马瑞男, 郭红仙, 程晓辉, 等. 微生物拌和加固钙质砂渗透特性试验研究[J]. 岩土力学, 2018, 39(S2):217-223. MA R N, GUO H X, CHENG X H, et al. Permeability experiment study of calcareous sand treated by microbially induced carbonate precipitation using mixing methods[J]. Rock and Soil Mechanics, 2018, 39(S2):217-223. (in Chinese)
[15] 马瑞男. 微生物拌和加固钙质砂试验研究[D]. 北京:清华大学, 2018. MA R N. Permeability experimental study on biocemented calcareous sand by mixing method[D]. Beijing:Tsinghua University, 2018. (in Chinese)
