浅析微生物矿化技术的工程应用研究进展

为研究微生物矿化技术(MICP)的工程应用情况,基于统计与总结归纳国内外相关文献的方法,介绍了其基本原理,统计和总结了MICP在岩土体防渗、加固、导热,污染土治理,砖石类文物建筑修复及混凝土裂缝修复领域的研究成果。结果表明MICP在众多工程领域具有较好的应用前景。     

微生物矿化沉积时空演化的微流控芯片试验研究

微生物矿化沉积是近年来的热门研究课题,然而人们对其时空演化过程的认识目前稍显不足.设计了具有大小孔隙的概念化微流控芯片,并利用微生物加固可视化系统对微生物矿化沉积的时空演化过程进行研究.提出了一种图像处理方法,该方法能够对沉积过程中的碳酸钙进行识别和计算,从而对微生物矿化沉积的时空演化过程进行量化研究.结果表明孔隙空间...     

微生物诱导碳酸钙沉淀技术修复劣化古建砖石砌体的试验研究

探索利用微生物诱导碳酸钙沉淀(MICP)技术,修复劣化古建砖石砌体的新方法。首先,对取自福建省三明市泰宁县某古建劣化砖石砌体,进行微生物诱导碳酸钙沉淀修复人造贯通裂缝试验。之后,对修复前后砖石进行超声波速试验、三点弯折试验、X射线衍射试验(XRD)和扫描电镜试验(SEM),从其外观、力学性能、材料性质和胶凝矿物成分等方面进行分析。试验结果表明：砖石贯通裂缝被完全修复,且表面致密,颜色与原砖石相近;贯通裂缝修复后抗弯强度最大值为0.67MPa;修复后,砖石贯通面超声波速最大值为1.46m/s,大于非贯通面超声波速的1.28m/s,表明修复后贯通裂缝处胶凝体密实度相对较高。XRD和SEM试验显示,贯通面中沉淀了以球霰石为主的碳酸钙矿物,且主要分布于砖石颗粒的表面和孔隙中,起到了很好的胶结作用。     

基于微生物诱导碳酸钙技术的软土地层微生物砂桩室内模型试验研究

微生物诱导碳酸钙沉淀技术（MICP）可有效地胶结砂土,基于MICP加固机理,研发了一套系统的微生物砂桩模型试验装置,进行了微生物砂桩的室内模型试验,探索了微生物砂桩的成桩效果,测试了其无侧限抗压强度,分析了微生物砂桩的可行性和有效性。研究结果表明：MICP技术可在软土地层中形成胶结良好的微生物砂桩,其整体性较好,无侧限抗压强度达235 kPa,破坏形态为半脆性破坏。     

微生物矿化胶结喀斯特岩石裂缝技术研究

针对喀斯特地貌的岩石表面裂缝宽度约2 mm这一特性,开展了微生物诱导碳酸钙沉淀胶结裂缝的试验研究,并通过修复剂对不同岩缝宽度及粗糙度的岩样进行裂缝胶结修复。结果表明:修复7 d的试样其修复深度能达到5 cm以上,且裂缝宽度在2 mm以内的岩样均能够被较好地修复;岩缝表面越粗糙、岩缝宽度越小,试样的体积修复率越高。经微生物矿化修复的岩样抗压强度恢复率为47.57%~93.67%,最高抗压强度可达81.8 MPa。经微生物矿化修复的岩石渗透系数维持在10-7 cm/s数量级上。生成的沉淀物以方解石和球霰石2种物相的碳酸钙晶体为主,与岩石基体具有高度的相容性。     

盾构法施工中泡沫剂效能及改良土体的试验研究

通过对自主研发的泡沫剂稳定性和发泡率等试验,得出了泡沫剂性能评价及土体改良后渗透性的变化规律.试验表明,泡沫剂对岩土渗透性能改良效果显著.该试验为复杂岩土盾构施工泡沫剂改良土体研究及工程应用提供了有价值的试验依据.     

微生物矿化动力学理论与模拟

微生物矿化技术作为一个新兴研究课题,近些年来得到了广泛关注,然而因其反应机制复杂,很难从时间和空间尺度对矿化反应过程进行定量表示。在微生物诱导碳酸盐沉淀原理的基础上,考虑细菌的吸附和筛滤效应,以及尿素水解动力学和沉淀动力学模型,对微生物矿化反应动力学理论进行了探究,并结合孔隙尺度下的微生物矿化反应试验,采用有限元软件进行多物理场耦合模拟。结果表明,细菌吸附和筛滤行为引起了细菌分布的差异性,而这种差异性进而影响了碳酸钙的沉积分布;溶液汇合初始段碳酸钙生成量横向分布不均匀,纵向分布呈增长趋势;经历40h的反应时间,渗透率可降低80%左右;当钙离子含量丰富时,碳酸钙沉淀速率受限于尿素水解速率;附着细菌量和沉淀速率的叠加效应表现为细菌被沉淀包裹的衰亡速率。本模型验证了微生物矿化沉积反应过程,丰富了微生物矿化反应理论,并有望为现场工程应用的效果预测提供参考。     

客运专线路基工程改良土施工技术

结合具体的工程实例,介绍了客运专线路基工程改良土的材料选择与配合比,详细地阐述了灰土的工程特性与施工工艺,探讨了灰土施工通病的质量控制措施,可用于指导现场施工。     

微生物矿化技术固化石墨尾矿的影响因素研究

研究了不同因素对石墨尾矿固化效果的影响,包括菌液浓度、胶结液浓度、胶结液pH和环境温度。采用正交试验设计,以试样无侧限抗压强度（UCS）为指标,评价试样的固化效果,并给出各因素的推荐值及对固化效果影响的优先顺序。     

Experimental study on mitigating wind erosion of calcareous desert sand using spray method for microbially induced calcium carbonate precipitation

Wind erosion is one of the significant natural calamities worldwide, which degrades around one-third of global land. The eroded and suspended soil particles in the environment may cause health hazards, i.e.allergies and respiratory diseases, due to the presence of harmful contaminants, bacteria, and pollens.The present study evaluates the feasibility of microbially induced calcium carbonate precipitation(MICP)technique to mitigate wind-induced erosion of calcareous desert sand(Thar desert of Raj...     

低温条件下微生物诱导碳酸钙沉积加固土体的试验研究

微生物诱导碳酸钙沉积(MICP)加固土体是近年来受到学术界重视的问题,但是对实际土壤温度下MICP加固土体的可行性及效果研究未见报道。利用尿素水解菌ATCC 11859,进行了微生物诱导碳酸钙沉积的试管试验及一维砂柱试验,研究了不同温度下微生物诱导生成碳酸钙的特性及对土体的加固效果。试管试验表明温度越高生成的碳酸钙越多,在不同温度下微生物诱导生成的碳酸钙晶型无显著差异,但是温度对碳酸钙的生成速率有明显影响。一维加固试验表明MICP在一般土壤温度条件下都能够有效地加固土体,但低温下MICP加固的试样强度较低,渗透系数较高。     

钻孔振击碎石桩加固地基的工程应用

对钻孔振击碎石桩做了初步简介，分析其加固地基的机理，结合工程实践详细阐述其施工流程和值得注意的具体细节，指出该桩型比当前常用的碎石桩具有更好的推广应用前景。     

Recycling of dredged river silt reinforced by an eco-friendly technology as microbial induced calcium carbonate precipitation (MICP)

A large amount of river silt is continuously dredged and usually dumped in landfills or oceans, resulting in land occupation and environmental pollution. Traditionally, cement-based materials are used to cement dredged river silt as building materials, which not only increases carbon dioxide emissions but also uses very little dredged silt. In order to realize the resource utilization of dredged river silt, microbial induced calcium carbonate precipitation (MICP) technology, which has the advantages of lower energy consumption, less environmental pollution and lower carbon emissions, is adopted to solidify the dredged river silt as roadbed materials in this paper. The unconfined compressive strength (UCS) test, calcium carbonate (CaCO₃) content test and microstructure test are carried out to analyze the mechanical properties of the solidified dredged river silt. The test results show that the MICP mixing method can be employed to solidify loose dredged river silt into high-strength construction materials. The concentration of the cementation solution has a significant effect on the solidification effect, and the most reasonable concentration of the cementation solution is 1.5 mol/L. With the increase of treatment times, the pores in the soil are filled with CaCO₃, and the UCS of the specimens after 10 times of treatment can reach 6.75 MPa with a relatively uniform CaCO₃ content of 27.8 %. The main crystal form of CaCO₃ is calcite, which can fill the pores and make the river silt particles cement as a whole, which is the main reason for the improvement of mechanical properties of dredged river silt.     

Application of microbially induced carbonate precipitation to form biocemented artificial sandstone

It is difficult to collect and characterise well-preserved samples of weakly-cemented granular rocks as conventional sampling techniques o ften result in destruction of the cementation.An alternative approach is to prepare synthetic geomaterials to match required specifications.This paper introduces microbially induced carbonate precipitation(MICP) as a method to reliably deliverartificially cemented specimens with customised properties,closely resembling those of so ft carbonate sandstones.The specimens are generated from materials with two highly different particle size distributions(PSDs) to access a range of achievable combinations of strengths and porosities.The MICP parameters are kept constant across all samples to obtain similar calcium carbonate characteristics(size of individual crystals,type,etc.),while injected volume is varied to achieve different cementation levels.Although uniform cementation of very coarse sands has been considered very difficult to achieve,the results show that both the fine and coarse sand specimens present high degrees of uniformity and a good degree of repeatability.The unconfined compressive strengths(UCSs)(less than 3000 kPa) and porosities(0.25-0.4) of the artificial specimens fall in the same range of values reported for natural rocks.The strength gain was greater in the fine sand than that in the coarse sand,as the void size in the latter was significantly larger compared to the calcium carbonate crystals' size,resulting in precipitation on less effective locations,away from contacts between particles.The strengths and porosities obtained for the two sands in this work fall within ranges reported in the literature for natural soft rocks,demonstrating the MICP technique is able to achieve realistic properties and may be used to produce a full range of properties by varying the grain sizes,and possibly the width of PSD.     

青海强盐渍粉砂土MICP的有效性探索

在极端环境中发现原生高产脲酶微生物并开展岩土体的固强研究,是岩土体微生物矿化研究的一个热点和难点.该文在青海柴达木地区的强盐渍土中发现一种新型原生高产脲酶微生物,在强盐环境中,试验该微生物的盐耐受性和矿化性能,开展被加固土体力学强度试验.结果表明:在强盐渍环境下,该新型微生物脲酶活性保持在3.02U～5.03U.在强盐...     

微生物水泥力学性能和耐久性的可持续应用研究进展

微生物沉淀技术涉及土木、生物、环境等多学科,是利用微生物自身代谢活动中矿化行为诱导碳酸钙快速沉淀的一种方法,本文介绍了微生物矿化作用及胶结过程,并从力学性能和耐久性等方面进行详细阐述,为土木工程的可持续应用研究提供了合理的建议。     

碳化法制备纳米碳酸钙的研究

利用氯化钙、氨水和二氧化碳为原料,采用碳化法制备纳米碳酸钙。考察了反应温度、CaCl2溶液浓度、CO2气体流量、添加剂等因素对碳酸钙粒子平均粒径、形貌和反应时间的影响,并用XRD和TEM对产物进行了表征。结果表明,使用一定种类添加剂,在20℃、0.4mol/L的CaCl2溶液和6mL/min流量的CO2条件下,可制得粒度分布均匀、分散性好、平均粒径为45nm左右的球形纳米碳酸钙。     

温度对微生物诱导碳酸钙沉积加固砂土的影响研究

利用尿素水解菌ATCC 11859,在10℃,20℃,30℃的环境下进行了微生物诱导碳酸钙沉积(MICP)水溶液试验、一维砂柱加固试验和细菌活性试验。研究表明,水溶液试验中,温度对于MICP的影响和反应时间有关,反应前期,温度较高的环境下钙离子消耗量较大,反应一段时间后温度较低的环境下钙离子消耗量较大;砂柱试验中,温度较低的环境下加固形成的砂样无侧限抗压强度较大,碳酸钙含量的检测表明,环境温度越高,砂柱中生成的碳酸钙含量越低;无侧限压缩试验的应力应变关系表明,相对低温条件下MICP处理的砂样在达到峰值强度时能够产生较大的变形;不同温度下细菌活性试验表明,细菌活性衰减较快是高温环境下碳酸钙的最终沉积量较小的原因。