中文摘要：

采用真三轴实验定量研究一般应力状态下泥浆渗入对泥水盾构开挖面土体剪切强度的影响，基于空间滑移面理论、三剪切角理论等考虑中主应力的破坏准则，研究天然土体一般应力条件下中间主应力对强度参数的影响规律。结合上海长江隧道工程，运用村山公式定量刻画同时考虑一般应力状态及泥浆作用时土体强度对泥水盾构开挖面有效泥浆支护压力设定值的影响程度。研究结果表明：对于砂质粉土，泥浆作用和中主应力的影响共同制约着有效泥浆压力的取值，且泥浆作用的影响更为显著，实验中有效泥浆压力相比天然土体情况提高了53％；而对于淤泥质黏土，泥浆作用及中主应力对泥水盾构开挖面的有效泥浆压力设定值影响较小，但中主应力系数的变化同样制约着泥浆作用对有效泥浆压力取值的影响程度。

英文摘要：

The effect of the slurry infiltration on the strength of the natural soil is quantitatively researched by true triaxial tests. And based on the spatially mobilized plane（SMP） failure criterion and trishear angle theorem theory, the dependency of soil strength parameters on the intermediate principal stress is illustrated theoretically. In addition, taking Shanghai Yangtze River tunnel for an example, the theory of Murayama formula is used to calculate the effective slurry support pressures considering the modified strength parameters based on the results of the true triaxial tests. And the influences of both slurry infiltration and the intermediate principal stress were taken into consideration in the aforementioned calculations. The results show that both the slurry infiltration and the intermediate principal stress have considerable effects on the shear strength parameters and slurry support pressures of sandy soil; especially the influence of slurry infiltration, which increases the effective slurry support pressure by 53% compared to the natural soil conditions. However, the effects of the slurry infiltration and the intermediate principal stress are relatively smaller on clay soil. Also the value of the intermediate principal stress ratio has important effect on the influence extent of the slurry infiltration and the effective slurry support pressure.