含水率对K_(30)值和E_(vd)值相关性的影响研究

Research on the Effect of Moisture Content on Correlation between K_(30) and E_(vd)

研究目的:K_(30)和E_(vd)均为检测路基压实质量力学指标的现场原位检测方法。一定条件下同类性质土中,K_(30)值和E_(vd)值线性相关性良好,但其相关性易受填料性质、施工工艺、气候状况等因素的影响,含水率是重要的影响因素之一。选取重庆地区某铁路工程中采用低液限粉质黏土填筑的路基进行K_(30)与E_(vd)的对比试验,研究含水率对K_(30)值和E_(vd)值相关性的影响。研究结论:(1) K_(30)值与E_(vd)值相关性受各种因素的影响显著,在有条件的情况下,应该通过K_(30)与E_(vd)的对比试验来确定其相关关系,尽量避免生搬硬套;(2)在较小含水率变化范围内,K_(30)值与E_(vd)值的线性相关性较好;当含水率变化范围为1%时,K_(30)-E_(vd)拟合曲线的相关系数R2值在0. 945 6～0. 981 9之间;随着含水率变化范围的增大,线性相关性变差;(3)随着含水率的增大,K_(30)值和E_(vd)值均呈现减小趋势;但E_(vd)值的减小速率大于K_(30)值;(4)随着含水率的增大,K_(30)-E_(vd)拟合曲线的一次项系数增大,常数项减小;(5)本研究成果可用于指导路基压实质量检测及路基填筑过程控制。

Research purposes:K30 and Evdare two site testing method for detecting mechanical properties of compacted quality of subgrade.There is a better linear correlation between K30 value and Evdvalue under the condition of relatively stable and same properties of subgrade filler.However,the linear correlation between them can be affected with properties of subgrade filler,construction craft of subgrade,climatic conditions,etc.The moisture content of subgrade filler is one of the most important influence factors.Therefore,in this paper,a section of the low liquid limit silty clays subgrade of a railway project in Chongqing was selected to conduct some contrast test research of K30 and Evdon the effect of moisture content on correlation between K30 value and Evdvalue.Research conclusions:(1)The influence of the various factors on the linear correlation between K30 value and Evdvalue was significant.Therefore,it was necessary to obtain the linear correlation between K30 value and Evdvalue by conduct some contrast test research of K30 and Evdunder permitting conditions,and try to avoid copying mechanically and applying slavishly other people’s experiences.(2)The linear correlation between K30 value and Evdvalue was better at the smaller moisture content range.The correlation coefficient of K30-Evdfitting curve was between 0.945 6 and0.981 9,when moisture content range was 1%.However,the linear correlation would become worse with moisture content range enlarging.(3)With the increase of moisture content,K30 value and Evdvalue showed the tendency of decrease,but Evdvalue decreased much faster than K30 value.(4)The monomial coefficient of K30-Evdfitting curve got bigger and its constant term got smaller with the increase of moisture content.(5)The research results can be applied to guide the detection of compaction quality of subgrade and the process control of subgrade filling.