Analysis of the effect of wheat straw flour on the pore structure of microbial induced carbonate precipitation (MICP) cemented desert aeolian sandy soil based on low field NMR

Abstract In the process of microbial curing of desert aeolian sandy soil, we thought of the water-holding properties of straw flour in view of the high proportion of fine particles and poor water retention of desert aeolian sandy soil, and therefore designed an experiment to add straw flour to enhance the effect of microbial curing of desert aeolian sandy soil. The sand columns prepared under different curing stages were analysed by low-field NMR techniques. The test results show that: (1) the curing product calcium carbonate can effectively fill the pores of the sand and reduce the total porosity, and the addition of straw powder increases the total porosity of the sand column, especially the number of large pores (5–60µm) increases significantly; (2) The addition of straw powder increased the original sand column pore volume and pore size, significantly increasing the water holding capacity of the cured sand column, and the free water content of the sand column was significantly greater than that of the original sand column;(3) The pore filling rate of the sand column decreased after mixing with straw powder, which improved the uniformity of calcium carbonate precipitation within the sand column, but the shear strength was lower than that of the original sand column. The results of the study provide a theoretical basis and data support for optimising the curing effect of desert aeolian sandy soil and its water-holding capacity.