基于复合地层表征参数的盾构隧道地面沉降预测分析

隧道盾构掘进过程中,复合地层围岩的特殊性质通常难以明确地量化表征,却对地面沉降影响甚大。针对这一问题,引入地层复合指数作为描述复合地层特征复杂程度的表征参数。依托某工程隧道地层组段的多项物理力学参数的数据特征,提出将复合地层变形模量的加权变异系数设置为地层复合指数;应用有限层法理论,分析复合地层中盾构掘进的有效推力、水平位移以及地面沉降的理论计算值与复合指数的关联性;同时,结合盾构掘进贯入度,通过数据拟合得到地层复合指数、贯入度、地面最大沉降值三者之间的关系式。工程实例验证表明,地层复合指数可以有效预测复合地层的盾构隧道地面沉降。

Prediction and analysis of ground settlement ofshield tunneling based on composite stratumcharacterization parameters

In the process of shield tunneling,the special properties of surrounding rock in composite strata are usually difficult to quantify,but it has a great impact on the ground settlement.In order to solve this problem,the formation composite index is introduced as a characterization parameter to describe the complexity of composite formation characteristics.Based on the data characteristics of many physical and mechanical parameters of a tunnel stratum section,it is proposed to set the weighted coefficient of variation of deformation modulus of composite stratum as stratum composite index.By using the theory of finite layer method,the correlation between the theoretical values of effective thrust,this paper analyzes the horizontal displacement and ground settlement of shield tunneling in composite stratum and composite index.Through data fitting,the relationship between formation composite index,penetration and maximum ground settlement is obtained.The engineering example shows that the ground composite index effectively predicts the ground settlement of shield tunnel in composite stratum.