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胶结砂样采用微生物诱导碳酸盐沉淀(MICP)技术制备。本文开展了X射线衍射、扫描电镜、无侧限抗压、三轴剪切等试验测试MICP试样。文中分析了试样的微观结构及物理力学参数,探讨了胶结物含量与砂样抗压强度、c’与φ’值之间的关系。研究结果表明:MICP沉积法产生的胶结物为碳酸钙;碳酸钙晶体主要粘附在骨架颗粒接触部位,并高度聚集封堵颗粒孔隙形成连接键,产生胶结作用而提高试样的力学性能;碳酸钙含量与砂样的力学性能提高有较好关联性。胶结砂样的碳酸钙含量可达到5.39%,其抗剪强度、黏聚力、内摩擦角分别提高423%、333%、35.7%,说明微生物固化砂土具有较好的应用意义。
Cementitious sand samples were prepared using microbial induced carbonate precipitation (MICP) technique. In this paper, X-ray diffraction, scanning electron microscopy, unconfined compressive, triaxial shearing and other tests to test MICP samples. In this paper, the microstructure and physico-mechanical parameters of the samples were analyzed, and the relationship between the content of cements and compressive strength of sand samples, c ’and φ’ values was discussed. The results show that the cement produced by the MICP deposition method is calcium carbonate. The calcium carbonate crystals mainly adhere to the contact parts of the skeleton particles and form highly aggregated particles to form the bond, which results in the cementation of the particles and improves the mechanical properties of the sample. Calcium content and the improvement of the mechanical properties of sand samples have a good correlation. The content of calcium carbonate in the cemented sand sample can reach 5.39%, and its shear strength, cohesion and internal friction angle increase by 423%, 333% and 35.7% respectively, which shows that the microbial solidified sand has good practical significance.