盾构掘进引起地表沉降的多因素敏感性分析

为了研究各因素在盾构法施工中对地表沉降的影响程度,基于敏感性分析原理,针对一地铁盾构实例,选取土体弹性模量、土仓压力、地下水等3个影响地表沉降的因素,通过变化某一基准参数,让其余影响因素固定,分析研究了盾构施工引起地表沉降对各因素的敏感性。结果如下:弹性模量提高10%时,地表累积最大沉降量可减小15%～20%;在地下水存在的情况下,地表沉降显著增大;而对于砂性土而言,土仓压力越高地表沉降值略有增加。研究结果表明:地表沉降对穿越地层的弹性模量和地下水比较敏感,而对土仓压力敏感性较小。

SENSITIVITY ANALYSIS OF FACTORS AFFACTING GROUND SETTLEMENT DURING SHIELD TUNNELING

Using the sensitivity analysis theory, elasticity of soil layer, pressure of soil storehouse and underground water are selected to be the sensitivity factors in a shield tunneling for a underground railway project. Furthermore, sensibility to the influential factors of ground settlement is analyzed by varying one parameter and keeping the other two factors constant. The theoretical results show that when the elastic modulus increases 10%, the total ground settlement will decrease 15%~20%, and it will evidently increase if the groundwater is encountered. Thus, we have to take the influence of groundwater into accountin the analysis. By contrast, ground settlement increases a little as the pressure of soil storehouse increases. Results shows that the settlement is much more sensitive to the elastic modulus and the groundwater and less sensitive to the pressure of soil storehouse.