为了提升微生物固化砂土的效果，从自然界微生物主动参与碳循环、激发碳化现象中得到启发，利用碳酸酐酶（carbonic anhydrase，简称CA）能显著提高CO2水合反应速率（提高108倍），促进脲酶（urease，简称UA）分解尿素生成的CO2迅速水合形成大量的特性，设计并进行了碳酸酐酶增强微生物矿化固化砂土试验，综合宏观物理力学试验和微细观检测，系统分析了碳酸酐酶对微生物固化砂土的增强效果及增强机制。结果表明：（1）碳酸酐酶能够显著提高砂土微生物加固过程中的胶结物产量，碳酸酐酶菌掺量在4%左右达到最佳，与常规微生物诱导碳酸盐沉淀（microbial-induced carbonate precipitation，简称MICP）相比，胶结物生成量提高了105.3%。（2）碳酸酐酶的掺入提高了固化体的抗压强度和抵抗变形能力，在0.25%～4.00%掺量范围内，固化土样的无侧限抗压强度随碳酸酐酶菌掺量的增加而增大。当掺量为4.00%时固化土样的强度达到1.915 MPa，为常规MICP固化试样强度的8.54倍。（3）碳酸酐酶没有改变MICP过程的产物，仍是方解石。但在添加了CA后，方解石的晶粒尺寸更大，六面体形状更规范，力学性能也更好。（4）在MICP过程中，脲酶和碳酸酐酶相互协同沉淀碳酸钙固化砂土。碳酸酐酶可以显著加速脲酶分解尿素生成的CO2水合并形成HCO3-和CO32-的速率，为矿化物沉降提供更有利的条件。碳酸酐酶

This study aimed to enhancethe efficiency of microbial-induced carbonate precipitation (MICP) forreinforcing sandy soil by inspiring natural processes involvingmicrobial-induced carbon cycling and carbonation. The experiment focused onenhancing MICP curing of sandy soil using carbonic anhydrase (CA)

whichsignificantly increases the reaction rate of CO2 hydration (108 times faster) and facilitates the rapid hydration of CO2 (producedby urease (UA) decomposition of urea) to form a substantial amount ofcarbonate. The effect of carbonic anhydrase on MICP-reinforced sandy soil andits underlying mechanism were systematically examined through a combination ofmacroscopic physical and mechanical tests and microfabrication tests. Theresults showed that: (1) CA significantly increases the production of cementduring the microbial consolidation of sandy soils

and the optimum dose ofcarbonic anhydrase producing bacteria is reached at about 4%

which increasesthe production of cement by 105.3%

compared with conventional MICP. (2) Theincorporation of CA improves the compressive strength and resistance of thecured body. In the range 0.25−4.00%

the unconfined compressive strength of thesolidified soil sample increases with the increase of the CA bacteria content.The strength of the cured soil sample reaches 1.915 MPa when the content is 4%

which is 8.54 times the strength of the conventional MICP cured sample. (3) CAdoes not change the product of the MICP process

it is still calcite

but afteradding CA

the grain size of the calcite is larger

the shape of the hexahedronis more standardised

and the mechanical properties are improved. (4) In theprocess of MICP

urease and CA co-precipitate calcium carbonate-cured sandysoil. CA can significantly accelerate the rate of urea-generated CO2 hydrate and form HCO3-and CO32-

providing more favourableconditions for mineralisation.