Study on mechanical properties of aeolian sand solidified by enzyme induced carbonate precipitation combined with fiber reinforced

Aeolian sand is a problematic soil formed by the transfer, transition, and deposition of rock particles in desert areas, which can easily cause land desertification. Traditional sand treatment methods are generally contrary to the strategy of green and low carbon, whereas enzyme-induced calcium carbonate precipitation (EICP) is an efficient, green, and durable solidification method, and coupled with fiber reinforcement, can significantly improve the sand strength and reduce brittle fracture. This paper investigated the mechanical characteristics of aeolian sand solidified by enzyme-induced calcium carbonate precipitation coupled with fiber reinforcement by conducting permeability and unconfined compression strength (UCS) tests. The test results indicated that the optimal solidified conditions for the EICP were that the dry density, bonding times, standing time, and enzyme cement ratio were 1.6 g/cm³, 5 times, 5 days, and 1:1, respectively. Under these conditions, the UCS reached its maximum of 392.52 kPa. When the fiber length and fiber content of basalt fiber were 6 mm and 0.75%, and that of wool fiber were 9 mm and 0.75%, respectively, the optimal reinforcement conditions were achieved, yielding maximum UCS values of 849.65 kPa and 885.31 kPa, respectively. Based on the test results, the solidified mechanism was revealed, involving pore filling and particle cementation by EICP products and the formation of a three-dimensional reinforcement network by fibers, synergistically enhancing strength and transforming brittle sand into a ductile solidified body. A Poly model considering fiber length, fiber content, and UCS was established and validated, showing excellent agreement with experimental data. The research results can offer a valuable guideline for the treatment of aeolian sand in desert areas.