Analysis of permeability characteristics of biochar amended clay based on nuclear magnetic resonance technique
YANG Haili1, LI Mingyu2*, NIAN Tengfei3
1. Gansu Seventh Construction Group Co., Ltd., Lanzhou, Gansu 730050, China; 2. School of Civil Engineering, Luoyang Institute of Science and Technology, Luoyang, Henan 471023, China; 3. School of Civil Engineering, Lanzhou University of Technology, Lanzhou, Gansu 730050, China
Abstract：Among the microscopic pore structure testing methods, nuclear magnetic resonance(NMR)testing technology has the advantages of wide testing pore range and fast testing speed. The mercury intrusion test technology can quantitatively study the soil pore distribution and pore size, but the test period is long. Therefore, a method based on mercury intrusion data to calibrate the NMR T2 spectral curve was proposed, and this method was used to quantitatively study the pore structure characteristics of modified clay with different biochar contents and its influence mechanism on permeability characte-ristics. The results show that with the increase of biochar content, the saturated permeability coefficient of the biochar-clay mixture increases gradually. Adding biochar to clay changed the pore structure of the clay. For pure clay, the T2 distribution curve has a unimodal structure. With the increase in biochar content, the T2 distribution curve showed a bimodal structure, the T2 spectrum shifted to the right, and the peak T2 gradually increased. Combined with the proportional relationship between T2 value and pore radius, it can be qualitatively judged that with the increase of biochar content, the most probable pore size of soil samples increases. Through the conversion coefficient C value between mercury intrusion data and NMR T2 spectrum, the most probable pore size corresponding to peak T2 was obtained, and the influence of the change of pore structure characteristics of biochar modified soil on the change of macroscopic permeability coefficient was quantitatively analyzed.
杨海丽,李明玉*,念腾飞. 基于核磁共振技术的生物炭改性土的渗透特性分析[J]. 排灌机械工程学报, 2023, 41(7): 682-688.
YANG Haili,LI Mingyu*,NIAN Tengfei. Analysis of permeability characteristics of biochar amended clay based on nuclear magnetic resonance technique. Journal of Drainage and Irrigation Machinery Engin, 2023, 41(7): 682-688.
