Abstract:Tunnel engineering projects are particularly vulnerable to seismic liquefaction hazards due to their long spans. In this study, researchers propose an electrolytic desaturation method based on the principle that reducing foundation saturation improves liquefaction resistance. For cut-and-cover tunnel projects in deep liquefiable sandy soil foundations, shaking table model tests were conducted to evaluate the reinforcement performance of the electrolytic desaturation method. Additionally, the soil acceleration around the tunnel, pore pressure variation, and tunnel uplift displacement were monitored. The test results showed that the electrolytic desaturation method provided excellent anti-liquefaction reinforcement performance, significantly restraining the uplift of tunnel structures. Pore pressure variation was the key factor affecting liquefaction occurrence. After the electrolysis of saturated sandy soils, a significant reduction in excess pore pressure was observed. Compared with the untreated condition, two conditions with different electrolytic treatments achieved maximum reductions of 68.1% and 70.3% in peak excess pore pressure. The positions of maximum reductions were all located at the bottom of the tunnel model, and the anode-cathode arrangement had a certain effect on both desaturation efficiency and anti-liquefaction performance. Both electrolytic treatments reduced the maximum uplift displacement of the tunnel model compared to the untreated condition, with reduction amplitudes exceeding 35%. The research findings demonstrate that the electrolytic desaturation method effectively controls the uplift deformation of tunnel structures in liquefiable foundations.
