Experimental Study About The Effect Of Microbial Products On Soil Properties

With the continuous development of China's infrastructure industry,in order to solve the practical problems of soil,the interdisciplinary research direction between new disciplines has received widespread attention.Although traditional soil improvers such as lime and Portland cement are effective in improving soil strength,but they can be environmentally unfriendly and cost high.Because microorganisms are naturally present in the soil,microbial life and physical-chemical actions can change the mechanical properties of the soil,such as compressive strength,shear resistance,deformation modulus and other related mechanical properties So that the soil can be regarded as a whole piece of living ecosystem,intended to borrow microorganisms to deal with soil,and then form a set of biochemical environment and geotechnical engineering together a comprehensive innovation and sustainable treatment.In order to explore the direct effect of microbial products on soil,the purified microbial product EPS(extracellular polymer)was mixed into clay with 1%,2% and 3% mass fraction respectively.The clay was modified,and its influence on the physical and chemical properties of the clay was studied at different time.The moisture content,shear strength and compressibility of the modified clay were investigated by soil shear test,direct shear test,consolidation slow shear test,SEM and X-ray diffraction experiments.From the above experiment,the research results and conclusions are as follows:1.The moisture content of the modified clay after the incorporation of EPS will be slightly improved.And EPS will be able to reflect the water retention of the clay.2.The cohesion of the modified clay after the incorporation of EPS is significantly reduced,and the higher the dosage of EPS,the more the cohesion of the modified clay is reduced.Although it is unfavorable to the bearing capacity of the foundation in a broad sense,it is worthwhile to consider the direction of modification if some of the clay requires green ecological slope protection or the special soil at the cultural relics need to reduce the cohesion of the soil.3.There are two kinds of internal friction angles of modified clay after incorporation of EPS.When the curing time is short,the internal friction angle is decreasing compared with the blank group.1% EPS content of the sample within the friction angle decreased by 8.78% compared with the blank group,2% EPS content of the sample cohesion than the blank group decreased by 4.09%,3% EPS content of the sample cohesion The blank group decreased by 0.73%.When the curing time is longer,the internal friction angle of the relatively blank group showed an increasing trend.The internal friction angle of the sample with 1% EPS content increased by 115.7% compared with the blank group,and the friction angle of the sample with 2% EPS content was 98% higher than that of the blank group.The friction angle increased by 51.72% compared with the blank group.4.The compressibility of the modified clay increases with the incorporation of EPS,and the modified soil changes from low-compression soil to medium-compressible soil,which is necessary for increasing the compressibility of soil Value.