水泥土动力特性室内试验及复合地基抗震特性分析

Experimental determination of dynamic properties of cement-treated soil and earthquake behavior of composite foundation

通过在 HX- 1 0 0多功能三轴仪上的动三轴试验及在 Drnevich L ong- Tor型共振柱仪上的竖向激振试验 ,研究了水泥土的动本构关系 ,指出水泥土的动应力应变骨干曲线可以用双曲线模型来描述 ,并且对水泥土的阻尼特性进行了探讨 .其次 ,探讨了水泥土材料的初始动弹性模量和水泥掺合比、围压的相互关系 .最后 ,利用 L oma地震记录 ,结合一维剪切梁模型 ,对水泥搅拌桩加固软土地基前后场地放大效应进行对比分析 。

The dynamic constitutive relationship of cement\|treated soils is given through dynamic triaxial tests using the HX\|100 triaxial test system and resonant column tests using the Drnevich Long\|Tor resonant device. These two types of dynamic tests were carried out to examine the influences of cement content and confining pressure on modulus and damping ratio of cement\|treated soil. As a result, it was found that the modulus and damping ratio of cement\|treated soil is extremely dependent on strain similarly to ordinary soil and hyperbolic model is proper as a mechanical model of the dynamic stress\|strain relationship necessary for the equivalent linearization method. The study of regularity how the initial dynamic Young modulus changes when the mixing ratios or confining pressures are changed is given as well. Finally, combining the project of 5×10\+4 m\+3 oil tank foundation in Nanjing, the authors compare the amplified coefficient of foundation soil before and after the soil treatment using CDM method. The conclusion is given that the CDM composite foundation is helpful to earthquake resistance in soft soils.