富水砂卵石地层力学特性研究  

Study on mechanical properties of water-rich sandy pebble soil

作　　者：张延杰 何萌 宋萌 曹立 赵海涛 李梅 ZHANG Yan-jie;HE Meng;SONG Meng;CAO Li;ZHAO Hai-tao;LI Mei(Yunnan Dianzhong Water Diversion Engineering Co.,Ltd.,Kunming,Yunnan 650000,China)

机构地区：[1]云南省滇中引水工程有限公司,云南昆明650000

出　　处：《岩土力学》2023年第6期1739-1747,共9页Rock and Soil Mechanics

基　　金：云南省重大科技专项计划项目(No.202002AF080003,No.202102AF080001)。

摘　　要：富水砂卵石地区的地铁盾构隧道工程建设中须有效掌握地层力学特性指标,以指导盾构施工参数的动态调整。针对传统地勘无法准确提供地层参数的问题,通过对成都地层分布与土质特征进行大数据统计分析,并结合室内剪切与渗透试验研究,探求富水砂卵石力学特性与细粒含量、含水率、水压力等主要参数间的影响关系。试验结果表明,随着含水率的增加,内摩擦角φ先降低后提高,咬合力C先提高后降低;当细粒含量从1%增加至6%,C和φ均出现不同程度的降低。推导出两个强度指标C值和φ角与细粒含量和含水率两个参数的变化关系表达式,以及砂卵石土的细粒含量与其饱和含水率两者的变化关系式,并通过拟合情况与实际数据验证了公式的可行性。得出卵石地层管涌型的渗透破坏类型,其渗透性随着土样细粒含量的增加有所减小。然后从开挖土层的性质分析反映出隧道掘进参数动态调整和渣土改良工艺对施工影响的内在机制。研究结果可为成都地区砂卵石土层抗剪强度进行经验公式参数选取、数值模拟取值,掘进关键技术与施工方案制定提供参考依据。It is essential to determine the mechanical properties of soils effectively during shield tunneling in the water-rich sandy pebble strata,which can be used to dynamically adjust the shield tunneling parameters.Since the conventional geological exploration cannot provide accurate strata parameters,the big data statistical analysis of stratum distributions and soil properties in Chengdu is conducted in combination with laboratory shear test and penetration test to explore the interaction between the mechanical properties of water-rich sandy pebble soils and the main parameters such as fines content,moisture content and water pressure.Test results show that with the increase in water content,the internal friction angle first decreases and then increases,while the interlocking force increases first and then decreases.The values of C andφdecrease to a certain extent as the fines content increases from 1%to 6%.The formulae for describing the relations of two strength indices of soils(C andφ)with the fines content and moisture content,as well as the equation for describing the relation between fines content and saturated moisture content,are derived.The feasibility of the proposed formulae is verified by fitting to the actual data.It is concluded that the failure pattern of the sandy pebble strata is piping type and the permeability of the sandy pebble strata declines as the fines content increases.Finally,the mechanism of the influences of tunneling parameters’dynamic adjustment and the muck improvement process on construction is investigated by analyzing the characteristics of the excavated layers.The research results can provide a reference for the selection of the shear strength parameters of the water-rich sandy pebble soil layer used in empirical formula,value selection in numerical simulation,key tunneling technologies and construction plans in Chengdu area.

关 键 词：砂卵石土 抗剪强度 渗透性 颗粒级配 细粒含量 含水率 

分 类 号：U231.3[交通运输工程—道路与铁道工程]