风积沙的微生物固化试验研究

张世参 骆亚生 田堪良 杜玉鹏 赵耀斌 李多

摘 要：風积沙主要分布在干旱少雨的沙漠地区，是一种结构松散、颗粒细小而均匀、自稳能力差且不易压实的特殊土体。为探讨大体积风积沙微生物固化规律，采用微生物诱导碳酸钙沉淀技术，利用巴氏芽孢杆菌，在饱和状态下对风积沙沙柱进行了微生物加固试验，测定了沙柱内不同深度处的细菌浓度以及细菌吸附量、酶活性、尿素浓度等指标。同时，分析了不同深度处固化试样的干密度、无侧限抗压强度和碳酸钙含量的变化规律。试验结果表明，细菌在沙柱中的最佳静置时间为4 h，胶结液在沙柱中的最佳静置时间为24 h。通过在风积沙中灌注巴氏芽孢杆菌菌液和胶结液可以在风积沙颗粒之间生成碳酸钙结晶，从而将沙颗粒黏结在一起，形成具有一定强度的整体。固化风积沙的无侧限抗压强度在0.43～7.13 MPa之间。微生物诱导碳酸钙沉淀技术固化风积沙的有效深度为0.2～0.7 m，固化沙柱不同位置处的干密度、无侧限抗压强度和碳酸钙含量随深度的变化规律相似，都是先升高后降低，在0.4 m左右处达到峰值。因此，采用微生物诱导碳酸钙沉淀技术可有效加固沙漠风积沙，能明显改善风积沙的工程性质。

关键词：微生物固化;微生物诱导碳酸钙沉积;风积沙;巴氏芽孢杆菌;工程力学性能

中图分类号：TU441 文献标志码：A

doi：10.3969/j.issn.1000-1379.2021.10.028

引用格式：张世参，骆亚生，田堪良，等.风积沙的微生物固化试验研究[J].人民黄河，2021，43（10）：144-149，160.

Abstract： Aeolian sand mainly distributes in arid and rainless desert areas. It is a kind of special soil with loose structure， fine and uniform particles， poor self-stabilization ability， and difficult to compact. Strengthening aeolian sand can improve the stability and wind erosion resistance of sand slope. Sporosarcina pasteurii was used to reinforce the aeolian sand column by microbial induced calcite precipitation. The bacterial concentration， adsorption capacity， enzyme activity and urea concentration of the samples at different depths in the sand column were measured. At the same time， the variation of dry density， unconfined compressive strength and calcium carbonate content of solidified samples at different depths were analyzed. The results show that the optimal static time of bacteria in sand column is 4 hours， and the optimal static time of cementing fluid in sand column is 24 hours. Calcium carbonate crystals can be formed between aeolian sand particles by filling sporosarcina pasteurii and cementing solution in aeolian sand， thus bonding sand particles together to form a certain strength of the whole. The unconfined compressive strength of solidified aeolian sand is between 0.43 MPa and 7.13 MPa. The effective depth of microbial-induced calcium carbonate precipitation solidifying aeolian sand is 0.2-0.7 m. The dry density， unconfined compressive strength and calcium carbonate content at different locations of reinforced sand column vary with depth similarly. They all increase first and then decrease， reaching the peak at about 0.4 m. Therefore， microbially induced calcite precipitation technology can effectively reinforce desert aeolian sand and significantly improve the engineering properties of aeolian sand， providing technical support for reinforcement of aeolian sand slope and improvement of wind erosion resistance.

Key words： microbial solidification; microbially induced calcium precipitation; aeolian sand; sporosarcina pasteurii; engineering mechanical properties

1 引 言

风积沙主要分布在干旱少雨的沙漠地区，是一种结构松散、颗粒细小而均匀、自稳能力差且不易压实的特殊土体，作为建筑物基础时须进行加固处理[1-2]。……