SICP方法加固饱和砂土提高抗液化能力的动三轴试验研究

在地震作用下,饱和砂土地基易达到液化状态，从而形成安全隐患。以标准砂为材料进行大豆脲酶诱导碳酸钙沉积（SICP）的胶结固化，对30%、40%和50%相对密实度下的中密砂分别做1~3次处理，进行不同循环剪应力与有效固结围压比值下的动三轴试验。通过分析动应变、超孔隙水压力、动循环次数，对SICP方法处理饱和砂土的抗液化效果进行评价。结果表明：试样的孔压与应变发展都呈现出分阶段增长的特点，孔压在加载瞬间会急剧增长到一定水平，而后伴随塑性应变以稳定的速率增长，直至破坏。SICP方法处理饱和砂土能有效增强砂土的抗液化能力，减缓超孔隙水压力的增长速度，且处理次数越多，密实度越高，抗液化效果越好。

Dynamic triaxial test analysis for saturated sand cemented by SICP-method aiming at improving liquefaction resisitance

Saturated sandy soil ground under earthquake is easy to reach liquefaction state which is of great threat. Soybean-urease induced carbonate precipitation (SICP) cement solidification was conducted using standard sand. Medium dense sand in the relative density of 30%, 40% and 50% was respectively solidified by the cementing fluid once, twice and three times, followed by a dynamic triaxial test under different CSR (ratio of cyclic shear stress to confining pressure). By analyzing dynamic strain, excess pore water pressure and the number of dynamic cycles, the effect of liquefaction resistance of the SICP-method in the treatment of saturated sand was evaluated. The results show that the pore pressure and strain development of the sample both show the characteristics of staged growth. The pore pressure will increase sharply to a certain level at the moment of loading, and then increase at a stable rate with the plastic strain until failed. The SICP-method can effectively enhance the liquefaction resistance of sandy soil and slow down the increasing trend of excess pore water pressure. And the more the number of treatments and the higher the compactness, the better the effect of liquefaction resistance.