基于盾构工程特征的砂卵石地层分类方法

Classification Method of Sandy Pebble Strata Based on Shield Engineering Characteristics

针对砂卵石地层盾构长距离高效掘进困难的弊端,在总结盾构掘进常见工程问题的基础上,提出粒径大小、细粒含量、水压高低以及磨蚀性能是制约盾构高效掘进的地层特征因素,分析各因素的特征指标、指标确定方法及指标量化区间,并根据指标量化区间划分出砂卵石地层类别。基于不同的地层类别匹配合理的盾构方案,通过组合指标下的砂卵石地层盾构实例,验证地层分类方法的适用性。研究结果表明:根据颗粒最大粒径dmax与螺旋输送机最大输排能力dp,可将砂卵石地层分为可输排及不可输排地层;根据细粒透镜层同区间总地层的占比λ,可将砂卵石地层分为高黏性低渗透及低黏性高渗透地层;根据地下水位高度hw及界限水位高度h0,可将砂卵石地层分为高水位及低水位地层;根据等效石英含量Qe,可将砂卵石地层分为高磨蚀性及低磨蚀性地层。提出的分类方法可为砂卵石地层盾构设计与施工提供理论指导和技术支持。

In response to the difficulty of long-distance and efficient shield tunneling in sandy pebble strata,this paper summarizes the common engineering problems of shield tunneling in sandy pebble strata and proposes that particle size,fine particle content,water pressure,and wear performance are the characteristic factors that restrict efficient shield tunneling;it also provides characteristic indicators,indicator determination methods,and indicator quantification intervals for each factor.Sandy pebble strata were classified based on the indicator quantification interval.According to different strata categories,the reasonable shield tunneling schemes is matched,and the applicability of the strata classification method was verified using a shield tunneling example in sand pebble strata under combined indicators.The research results indicate that sandy pebble strata can be divided into transportable and non-transportable strata according to the maximum particle size dmax and maximum discharge capacity d of the screw conveyor dp;according to the proportion of total strata in the same interval of fine-grained lens layer a,the sandy pebble strata can be divided into high viscosity,low permeability,and low viscosity,high permeability strata;according to the height of groundwater level hw and limit water level height ho,the sandy pebble strata can be divided into high water level and low water level strata;Based on the equivalent quartz content Qe,the sandy pebble strata can be classified into high-and low-abrasive strata.This classification method provides theoretical guidance and technical support for the design and construction of shield tunneling in sandy pebble strata.