淤泥质粉质黏土温控动三轴试验

Temperature-Controlled Dynamic Triaxial Test of Mucky Silty Clay

针对宁波市轨道交通2号线一期工程,利用温控动三轴试验系统,开展淤泥质粉质黏土的动力特性试验,研究温度、加载频率、动应力幅值对土体的累积塑性应变、动弹性模量、阻尼比和孔压等的影响。结果表明:淤泥质粉质黏土的动力特性发展规律受动应力幅值的影响很大,当动应力幅值接近临界动应力时,增大振动频率会降低临界动应力值;在相同应力水平下,淤泥质粉质黏土的强度随着温度的升高而增大,呈现热硬化趋势;在不同的动应力幅值、振动频率和温度下,淤泥质粉质黏土的动弹性模量和阻尼比随动应变的增大而减小,动应变随动应力比的增大而增大,近似呈线性增长。

Based on the temperature-controlled dynamic triaxial test system, the dynamic characteristics test was carried out on the mucky silty clay in the phase one project of Ningbo rail transit Line ~ The influence of temperature, loading frequency and the amplitude of dynamic stress on soil in such aspects as the accumulated plastic strain, dynamic elastic modulus, damping ratio, pore pressure and so on was studied. The results show that the amplitude of dynamic stress has great influence on the development law of the dynamic characteristics of mucky silty clay. When the amplitude of dynamic stress approaches to the critical dynamic stress, the critical values of dynamic stress can be reduced by increasing vibration frequen- cy. Under the same stress level, the strength of mucky silty clay increases with the increase of temperature and presents the thermosetting trend. Under different dynamic stress amplitudes, vibration frequencies and temperatures, the dynamic elastic modulus and damping ratio of mucky silty clay decrease with the increase of dynamic strain, and the dynamic strain increases almost linearly with dynamic stress ratio.