微生物诱导矿化修复阿尔寨石窟红砂岩壁面酥碱病害试验研究

Experimental study on the treatment of salt efflorescence on the wall of red sandstonein Arjai Grottoes based on the MICP technology

阿尔寨石窟寺是内蒙古地区规模最大且保存最为完整的石窟寺建筑群,其蕴含了珍贵的关于历史、宗教、科学、文化的艺术价值,被誉为“草原上的敦煌”。由于当地典型的沙旱寒区气候特征,酥碱成为石窟壁面最为严重的病害之一,目前阿尔寨石窟正处于保护阶段,因此通过室内对病害进行模拟和研究尤为重要。本研究通过微生物诱导碳酸钙沉淀(MICP)技术,对以红砂岩风化土为基质的壁面的酥碱病害进行修复,通过激光粒度分析了病害前后土颗粒粒径的变化,提出酥碱高度、酥粉体积、盐壳厚度的量化指标用以评价病害的发展程度。基于微生物矿化技术生成矿化覆膜对病害进行抑制,推荐使用微生物菌液浓度OD_(600)大于1.5的具有耐盐碱性能的矿化菌株,修复后酥碱高度下降幅度大于20%,酥粉体积下降幅度大于30%,盐壳厚度下降幅度大于25%。研究成果对生物矿化技术应用于红砂岩石窟壁面的酥碱病害的修复进行试验验证和可行性评估,为绿色生态环保的岩壁病害修复与加固技术的推广应用进行科学预研。

Arjai Grotto Temple is the largest and most completely preserved grotto temple complex in Inner Mongolia.It contains precious artistic information about history,religion,science and culture,and is known as“Dunhuang on the grassland”.Due to the typical climatic characteristics of the local arid and cold regions,salt efflorescence has become one of the most serious diseases of grotto walls.At present,Arjai Grottoes are in the stage of protection,so it is particularly important to simulate and study the diseases indoors.In this study,the microbial induced calcium carbonate precipitation(MICP)technology was used to treat the salt efflorescence on the wall with weathered red sandstone soil as the matrix.The change of soil particle size before and after the disease was obtained by laser particle size analysis,and the physical indexes of plaster disruption height,powder volume and salt crust thickness were used to evaluate the degree of development of the disease.Based on the microbial mineralization technology,a mineralized film was generated to inhibit the disease.It is recommended to use the mineralized strain with a concentration of microbial liquid—OD_(600)greater than 1.5,which has the salt-tolerant performance.After the treatment,the height of plaster disruption decreased by more than 20%,the volume of powder decreased by more than 30%,and the thickness of salt crust decreased by more than 25%.We carried out experimental verifications and feasibility evaluations of the application of biomineralization technology to the treatment of salt efflorescence on the wall of red sandstone grottoes,the results of which could provide scientific pre-research on the promotion and application of green ecological and environmentally friendly technologies for rock wall restoration and reinforcement.