Conventional materials necessitate a layer-by-layer rolling or tamping process for subgrade backfill projects, which hampers their utility in confined spaces and environments where compaction is challenging. To address this issue, a self-compacting poured solidified mucky soil was prepared. To assess the suitability of this innovative material for subgrade, a suite of performance including flowability, bleeding rate, setting time, unconfined compressive strength (UCS), and deformation modulus were employed as evaluation criteria. The workability and mechanical properties of poured solidified mucky soil were compared. The durability and solidification mechanism were investigated. The results demonstrate that the 28-day UCS of poured solidified mucky soil with 20% curing agent content reaches 2.54 MPa. The increase of organic matter content is not conducive to the solidification process. When the curing temperature is 20 degrees C, the 28-day UCS of the poured solidified mucky soil with curing agent content not less than 12% is greater than 0.8 MPa. The three-dimensional network structure formed with calcium silicate hydrate, calcium aluminate hydrate, and ettringite is the main source of strength formation. The recommended mud moisture content is not exceed 85%, the curing agent content is 16%, and the curing temperature should not be lower than 20 degrees C.

Soil nonlinear behavior displays noticeable effects on the site seismic response. This study proposes a new functional expression of the skeleton curve to replace the hyperbolic skeleton curve. By integrating shear modulus and combining the dynamic skeleton curve and the damping degradation coefficient, the constitutive equation of the logarithmic dynamic skeleton can be obtained, which considers the damping effect in a soil dynamics problem. Based on the finite difference method and the multi-transmitting boundary condition, a 1D site seismic response analysis program called Soilresp1D has been developed herein and used to analyze the time-domain seismic response in three types of sites. At the same time, this study also provides numerical simulation results based on the hyperbolic constitutive model and the equivalent linear method. The results verify the rationality of the new soil dynamic constitutive model. It can analyze the mucky soil site nonlinear seismic response, reflecting the deformation characteristics and damping effect of the silty soil. The hysteresis loop area is more extensive, and the residual strain is evident.