考虑级配影响的珊瑚砂最大动剪切模量试验研究  

Small-strain shear modulus prediction model related to grain gradation of coral sand

作　　者：梁珂 岳冲 周正龙[2] 杭天柱 LIANG Ke;YUE Chong;ZHOU Zhenglong;HANG Tianzhu(Key Laboratory of Urban Security and Disaster Engineering of China Ministry of Education,Beijing University of Technology,Beijing 100124,P.R.China;Institute of Geotechnical Engineering,Nanjing Tech University,Nanjing 210009,P.R.China)

机构地区：[1]北京工业大学城市与工程安全减灾教育部重点实验室,北京100124 [2]南京工业大学岩土工程研究所,南京210009

出　　处：《土木与环境工程学报（中英文）》2023年第6期95-103,共9页Journal of Civil and Environmental Engineering

基　　金：北京市自然科学基金(8224082);中国博士后科学基金(2021M700309)。

摘　　要：对不同级配的南沙岛礁珊瑚砂进行共振柱试验,测试不同孔隙比e的珊瑚砂在20~300 kPa围压下的最大动剪切模量G_(0),分析不均匀系数C_(u)、平均粒径d_(50)和细粒含量F_(c)对珊瑚砂G_(0)的影响,并建立珊瑚砂的G_(0)经验模型。结果表明:珊瑚砂的孔隙比e普遍大于陆源砂砾土;同一有效围压σ'0下,珊瑚砂的G_(0)-e曲线随C_(u)的增大而降低,随d_(50)的增大而升高,以F_(c)≈20%为界,随F_(c)的增大先降低后缓慢升高;陆源砂砾土的G_(0)经验模型将低估珊瑚砂的G_(0)值;F_(c)对G_(0)影响的本质是不同细粒含量的珊瑚砂具有不同的C_(u)和d_(50),C_(u)和d_(50)对G_(0)的影响隐含了F_(c)对G_(0)的影响。基于Hardin模型给出考虑C_(u)、d_(50)影响的珊瑚砂G_(0)预测模型,并引入修正系数A',以考虑颗粒类型等复杂因素的综合影响,采用不同海洋珊瑚砂的试验数据对G_(0)预测模型进行验证。A series of resonant column tests were conducted on coral sand taken from the Nansha Islands,South China Sea with different grain gradations.The small-strain shear modulus G_(0) of the coral sands with various void ratio e with the confining stress of 20~300 kPa was obtained.The influence of coefficients of uniformity C_(u),mean particle size d_(50),and fines content F_(c) on G_(0) of coral sand was investigated,and the G_(0) formulation for coral sand was established.For the constant effective confining pressureσ'0,the curve of G_(0)-e moves downward as the increasing C_(u),and moves upward as the increasing d_(50).The G_(0) firstly decreases and then increases as the increasing F_(c),and the G_(0) reaches the minimum value for F_(c) of about 20%.The G_(0) prediction equations of terrigenous sandy and gravelly soils will obviously underestimate the G_(0) value of coral sand.The influence of F_(c) on G_(0) essentially results from the change of C_(u) and d_(50) for coral sand with various F_(c).The G_(0) prediction equation of coral sand related to C_(u) and d_(50),which implies the influence of F_(c) on G_(0),was proposed,and the correction factor A'related to the morphology and mineralogy of the particle form of coral sands was incorporated in the proposed G_(0) prediction equation.The validity of the G_(0) prediction equation was verified by comparing the measured and predicted G_(0) values of coral sands from different seas.

关 键 词：珊瑚砂 最大动剪切模量 共振柱试验 级配 

分 类 号：TU441[建筑科学—岩土工程] TU411.8[建筑科学—土工工程]