石灰磷石膏稳定红黏土动力特性试验研究

Experimental Study on Dynamic Characteristics of Lime Phosphogypsum Stabilized Red Clay

采用室内SDT-20动三轴试验机对素红黏土和石灰磷石膏稳定红黏土进行了动力特性试验。研究了不同围压、固结比和振动频率下的素红黏土和石灰磷石膏稳定红黏土的动剪切模量和阻尼比变化规律;提出了动剪切模量和阻尼比的动本构关系。研究结果表明:素红黏土和石灰磷石膏稳定红黏土随围压、固结比、频率和石灰含量增大而增大;阻尼比随围压、固结比、频率和石灰含量的增大逐渐减小;在相同条件下,石灰磷石膏稳定土最大动剪切模量比素红黏土大得多,最大阻尼比比素红黏土小得多;素红黏土和石灰磷石膏稳定红黏土的动剪切模量、阻尼比与动剪切应变本构关系符合H-D模型;掺入石灰与磷石膏可显著提高红黏土动剪切模量,降低阻尼比。这说明石灰磷石膏稳定红黏土能提高土体强度,增加土体抵抗动剪切变形性能、降低能量损耗。

The dynamic characteristics tests of plain red clay and lime phosphogypsum stabilized red clay were carried out by indoor SDT-20 dynamic triaxial testing machine.The variation laws of dynamic shear modulus and damping ratio of plain red clay and lime phosphogypsum stabilized red clay under different confining pressures,consolidation ratios and vibration frequencies were studied,and the dynamic constitutive relationship between dynamic shear modulus and damping ratio was proposed.The research results show that plain red clay and lime phosphogypsum stabilized red clay increase with the increase of confining pressure,consolidation ratio,frequency and lime content.The damping ratio decreases gradually with the increase of confining pressure,consolidation ratio,frequency and lime content.Under the same conditions,the maximum dynamic shear modulus of lime phosphogypsum stabilized soil is much larger than that of plain red clay,and the maximum damping ratio is much smaller than that of plain red clay.The constitutive relationship between the dynamic shear modulus,damping ratio and dynamic shear strain of plain red clay and lime phosphogypsum stabilized red clay conforms to the H-D model.The addition of lime and phosphogypsum can significantly improve the dynamic shear modulus of red clay and reduce the damping ratio.It is indicated that lime phosphogypsum stabilized red clay can improve soil strength,increase soil resistance to dynamic shear deformation and reduce the energy loss.