干湿循环条件下人工制备遗址土动力特性试验研究

Experimental study on dynamic characteristics of artificial ruins under drying-wetting cycles

为研究干湿循环条件下糯米浆修复土遗址的适用性,静压制备不同糯米浆掺量的遗址土试样,对其进行不同次数的干湿循环作用后开展动三轴试验,得到人工制备遗址土动力特性及结构性的变化规律。结果表明:糯米浆可显著提升土体动强度并有效控制动变形的增长;土与糯米浆质量比为90∶10时,试样的骨干曲线和动剪切模量最大,阻尼比最小;干湿循环作用使人工制备遗址土的骨干曲线和动剪切模量降低,阻尼比增大;随着糯米浆掺量的增大,干湿循环对土体动力特性的影响逐渐减弱。经历5次干湿循环后动剪切模量比和阻尼比总体趋于稳定,对其分别进行非线性回归分析,并建立相应的归一化拟合模型。依据综合结构势理论所定义的动力结构性参数能够反映干湿循环及剪切过程中土体结构性的劣化程度,干湿循环次数和围压增大,结构性参数随之减小;糯米浆掺量增大,结构性参数呈先增大后减小的趋势。

In order to research the applicability of glutinous rice slurry for ancient ruins restoration under dryingwetting cycles,the ancient ruin samples with different contents of glutinous rice slurry were prepared by static pressing,the dynamic triaxial test was carried out after different times of drying and wetting cycles to obtain the dynamic characteristics and structural evolution law of the artificially prepared ruins.The results show that the dynamic strength of soil can be improved significantly and the dynamic deformation can be controlled effectively,When the mass ratio of soil to glutinous rice slurry is 90∶10,the backbone curve and dynamic shear modulus of the sample are the largest,and the damping ratio is the smallest.The drying-wetting cycles reduce the backbone curve and dynamic shear modulus of the artificially prepared site soil,and increases the damping ratio.With the increase of the content of glutinous rice slurry,the influence of drying-wetting cycles on the dynamic characteristics of soil gradually weakened.Dynamic shear modulus ratio and damping ratio tend to be stable after 5 cycles of wetting and drying,nonlinear regression analysis is performed on them respectively,and the corresponding normalized fitting model was established.The dynamic structural parameters defined by the comprehensive structural potential theory can well quantify the deterioration degree of soil structure in the drying-wetting cycles and shear process,The structural parameters decrease with the increase of drying-wetting cycles and confining pressure.When the content of glutinous rice slurry increases,the structural parameters first increase and then decrease.