利用从黄豆粉中自提取的脲酶诱导碳酸钙晶体沉积（EICP）技术是岩土工程领域新兴起的一种岩土体改良技术，该技术具备经济、绿色、与环境友好等诸多优点。然而，自提取豆酶液的浊度较高，生物灌浆过程中易发生生物堵塞现象，使得沿深度的生物固化效果较差。为此，本文采用含明矾的溶剂提取豆酶液以降低其浊度，并通过一系列宏微观试验及测试，研究不同明矾含量对豆酶液浊度、脲酶活性及生物固化效果的影响。结果表明：含明矾的溶剂可显著降低所提取豆酶液的浊度，但过量的明矾（如豆粉含量为100 g/L时，明矾含量超过3.0 g/L）也会导致其脲酶活性降低甚至丧失。豆酶液浊度的降低有利于改善所诱导沉积碳酸钙晶体沿深度分布的均匀性，进而提高固化砂土的无侧限抗压强度，但对所诱导沉积碳酸钙晶体的类型及结晶度并无明显影响。

Enzyme Induced Carbonate Precipitation (EICP) technology using self-extracted soybean urease is an emerging soil improvement technology in geotechnical engineering. This technology has many advantages, such as economic, green and environmentally friendly. However, the high turbidity of the self-extracted soybean urease solution can cause bioclogging during the biogrouting process, resulting in poor biocementation along the depth. In this study, a solvent containing alum was used for the extraction of soybean urease solution to reduce its turbidity. A series of macroscopic and microscopic experiments and tests were conducted to investigate the effects of alum content on turbidity and biocementation of the extracted soybean urease solution. The results indicate that the use of the alum-containing solvent can effectively reduce the turbidity of the self-extracted soybean urease solution. However, excessive amounts of alum (e.g., more than 3.0 g/L for 100 g/L of soybean powder) may cause the urease activity of the soybean urease solution to decrease or drop to zero. The use of soybean urease solution with low turbidity is beneficial to improve the distribution uniformity of precipitated calcium carbonate along the depth, thereby enhancing the strength of the biocemented sand, while having no apparent effect on the morphology and crystallinity of the precipitated calcium carbonate crystal.

国家自然科学基金(42477160, 52178319, 52108307, 51708243)；福建省自然科学基金(2022J05020,2022J05127)