Abstract:Based on the road construction project of Fengming Road affiliated with the Lego Park in Jinshan District of Shanghai, the field test research is conducted on the fluidized solidified silt backfill subgrade. First, the laboratory tests are performed to determine the fluidity and strength characteristics of the solidified silt in order to establish the optimal mix ratio for pouring the silt solidified soil subgrade on site. And the fiber Bragg grating sensors are embedded on site to collect the deformation and temperature data during the curing and hardening stages of the solidified silt layer. After the curing period, the tests are conducted to determine the structural performances of the subgrade. The results show that during the initial 75 h of curing, the temperature and strain changes of the silt solidified soil can be divided into three stages of rise, decline and stabilization. The temperature rises to 24.03℃ at 17 h and then begins to drop, and stabilizes after 56 h. The horizontal strain of the solidified soil at a depth of 26 cm is relatively small, but the vertical strain will increase with the increase of depth, and the strain at the lowest measurement point reaches 188.82 με. After 7 d of curing, the specific penetration resistance of the silt-solidified soil subgrade exceeds the design value. After 14 d, it will increase to 1 MPa, which is significantly higher than that of the calcareous soil subgrade. The bearing capacity of subgrade meets the road construction standard values at both 7 d and 14 d. The deflection is mainly concentrated between 280 and 300, meeting the design standard values.
