重载铁路水泥改良膨胀土路基填料动弹模量及阻尼比研究  

LABORATORY TESTS ON DYNAMIC MODULUS AND DAMPING RATIO OF CEMENT-STABILIZED EXPANSIVE SOIL AS SUBGRADE FILLING OF HEAVY HAUL RAILWAY

作　　者：商拥辉[1,2] 徐林荣[2] 黄亚黎 陈钊锋 SHANG Yonghui;XU Linrong;HUANG Yali;CHEN Zhaofeng(Institute of Architecture and Engineering,Huanghuai University,Zhumadian 463000,China;School of Civil Engineering,Central South University,Changsha 410075,China)

机构地区：[1]黄淮学院建筑工程学院,驻马店463000 [2]中南大学土木工程学院,长沙410075

出　　处：《工程地质学报》2020年第1期103-110,共8页Journal of Engineering Geology

基　　金：国家自然科学基金项目(资助号:51078358)~~

摘　　要：动弹模量与阻尼比是土动力学分析中的重要力学参数,考虑重载铁路荷载特征定量分析水泥改良膨胀土的动模量和阻尼比的较少。依托蒙西至华中地区铁路煤运通道(简称蒙-华铁路)工程为背景,采用南阳邓州市大山寨膨胀土,通过在不同频率、围压、固结比及动应力幅值下的持续振动三轴试验,研究了水泥掺量3%和5%水泥改良膨胀土的动弹模量及阻尼比,并与膨胀土素土进行对比分析。结果表明:水泥掺量3%和5%改良膨胀土的最大动弹模量约为膨胀土素土的3~4倍;在动弹模量-应变曲线中,动应变小于0. 002时表现为陡降段,动弹模量随动应变增长降幅达70%,而动应变大于0. 002时降幅较小,动弹模量随动应变增长趋于稳定;动弹模量随围压、频率、水泥掺量增加而增大,阻尼比随围压、固结比增加而减小;低应变水平下,固结比与动模量成正相关关系,高应变水平下,固结比与动弹模量成负相关关系。同时,对动弹模量及阻尼比进行了归一化分析,建立了估算动弹模量及阻尼比的经验公式。Dynamic elastic modulus and damping ratio are important mechanical parameters in soil dynamics analysis. Considering the characteristics of heavy-duty railway loads,the dynamic modulus and damping ratio of cement-stabilized expansive soil are less. Based on the background of the railway coal transportation channel( hereinafter referred to as Meng-Hua Railway) in the central area of the city of Tolemon and the central China,the dynamic modulus and damping ratio of 3% and 5% cement reinforced expansive soils were studied and compared with the expanded soil from Dashanzhai expansive soil in Dengzhou City,Nanyang,under the consolidation with different frequencies,confining pressure,ratio and dynamic stress amplitude. The results were compared with expansive soils. The results show that the maximum dynamic modulus of cement modified with 3% and 5%modified expansive soil is about 3-4 times that of expansive soil. When the dynamic strain is less than 0. 002,the dynamic elastic modulus has a steep drop and decreases by 70%. In the dynamic elastic modulus-strain curve,when the dynamic strain is greater than 0. 002,the decrease is small,and the dynamic elastic modulus tends to be stable with the dynamic strain. The dynamic elastic modulus increases as the confining pressure,the frequency and the cement content increase. Damping ratio decreases as the confining pressure and consolidation ratio increase. At low strain levels,the consolidation ratio is positively correlated with the dynamic modulus. At high strain levels, the consolidation ratio is inversely related to the dynamic modulus. At the same time,the dynamic modulus and damping ratio are normalized and analyzed,and an empirical formula for estimating the dynamic modulus and damping ratio is established.

关 键 词：重载铁路 水泥改良膨胀土 动模量 阻尼比 

分 类 号：U416.167[交通运输工程—道路与铁道工程]