复杂富水地层盾构掘进速率评价及预测方法研究

Research on Evaluation and Prediction Method of Shield Tunneling Speed in Complex Water Rich Strata

富水地层由于地质情况复杂多变,影响盾构机的掘进性能。为了分析该种地层种盾构隧道掘进性能,预测掘进速率,以绍兴市轨道交通1号线玉山路站—阳和路站区间盾构工程为例,首先分析了掘进速率在掘进过程中的变化,研究地层物理力学参数对盾构掘进速率的影响。最后基于径向基函数模型,对富水地层中盾构掘进速率进行预测。研究发现,黏土和粉质黏土地层在掘进后期会引发刀盘结“泥饼”,降低盾构机掘进速率;含黏性土圆砾地层透水性良好,富含承压水,掘进速率较黏土和粉质黏土地层高;掘进速率与黏聚力c、塑性指数IP、地基承载特征值fak和标贯锤击数N整体呈负相关关系,而与垂直渗透系数kv呈正相关关系;存在最优含水率使得掘进速率最高。所提出的径向基函数模型可有效提高富水地层盾构机掘进速率的预测精度。研究成果将为相关地层情况下盾构隧道施工方案设计提供参考。

Due to the complex and variable geological conditions,the excavation performance of shield tunneling machines is affected by the rich water strata.In order to analyze the excavation performance of this type of shield tunnel and predict the excavation rate,taking the shield tunneling project between Yushan Road Station and Yanghe Road Station on Shaoxing Metro Line 1 as an example,the variation of excavation rate during the excavation process was first analyzed,and the influence of physical and mechanical parameters of the strata on the shield tunneling rate was studied.Finally,based on the radial basis function model,the shield tunneling speed in rich water strata is predicted.Research has found that clay and silty clay layers can cause cutterhead formation"mud cake"in the later stage of excavation,reducing the excavation speed of shield tunneling machines;The stratum with cohesive soil and round gravel has good permeability and is rich in pressurized water.The excavation rate is higher than that of clay and silty clay layers;The excavation speed is negatively correlated with the cohesive force c,plasticity index IP,foundation bearing characteristic value fak,and standard penetration hammer number N,while positively correlated with the vertical permeability coefficient kv;There exists an optimal moisture content that maximizes the excavation rate.The proposed radial basis function model can effectively improve the prediction accuracy of shield tunneling machine excavation speed in water rich strata.The research results will provide reference for the design of shield tunnel construction schemes under relevant geological conditions.