Dynamic Tests on the Cement-improved Loess under the Vibratory Load
Dynamic Tests on the Cement-improved Loess under the Vibratory Load
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发表时间：
2013
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通讯作者：
Xie Wan-li
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作者：
Xie Wan-li
通过动三轴试验，研究了深度、水泥掺入比、击实系数、浸水条件、振动频率等试验因素对水泥改良黄土动变形、动弹性模量、阻尼比等动力特性的影响顺序和贡献率。获得了大量的黄土剖面试验样品，包括不同地貌单元的典型黄土剖面，并对水泥土的动力学参数进行了研究。在大陆动力学国家重点实验室GDS先进动三轴试验系统上，采用正交试验方法对试验进行了优化，根据试验结果计算了动荷载不同深度的振动衰减规律，通过击实试验制作不同水泥比的黄土试样，通过长周期和大量循环的动力试验，测定了水泥改良黄土的动变形、动弹性模量和阻尼比等动力特性，结果表明，在试验因子水平范围内，影响振动沉降的因素主次顺序为：水泥比、浸水条件、振动频率、振深、压实系数，另外，水泥比和水-浸泡条件对动弹性模量影响显著，影响动弹性模量的因素主次顺序为深度浸水条件、水泥比、振动频率、压实系数、浸水深度和浸水条件对阻尼比的影响显著，影响阻尼比的因素主次顺序为浸水条件、水泥比、振动频率、压实系数、浸水深度，水泥比和浸水条件对阻尼比的影响极显著，因此，水泥比的增加导致水泥改良黄土的动力特性的显著改善;没有注意到最佳的水泥比。
In this paper dynamic triaxial tests were performed to explore the order and contribution rate of experiment factors such as depth,cement commingle ratio,compacting factor,water-dipping conditions,and vibration frequency on the dynamic characteristics of cement-improved loess including dynamic deformation,dynamic elastic modulus,and damping ratio.On the basis of the foundation construction of the Datong-Xi'an high-speed railway,a large number of test samples have been obtained that include typical loess profiles of various geomorphic units.The dynamic parameters of cement-improved loess were tested on the GDS advanced dynamic triaxial test system at the State Key Laboratory of Continental Dynamics.The orthogonal test method was applied to optimize testing.The dynamic load was calculated according to the train vibration attenuation rule of various depths.Loess samples of various cement ratios were created through compaction tests.The dynamic characteristics of cement-improved loess such as dynamic deformation,dynamic elastic modulus,and damping ratio were determined from dynamic tests that included lengthy periods and a large number of cycles.The results showed that within the test factor level range,the primary and secondary order of factors that affected the vibrated subsidence were cement ratio water-dipping conditions vibration frequency depth compacting factor.In addition,cement ratio and water-dipping conditions showed significant influence on dynamic deformation.The primary and secondary order of factors that affected the dynamic elastic modulus were depth water-dipping conditions cement ratio vibration frequency compacting factor.In addition,depth and submerged conditions showed significant influence.The primary and secondary order of factors that affected the damping ratio were submerged condition situation cement ratio vibration frequency compacting factor depth.In addition,cement ratio and submerged conditions showed highly significant influence.Therefore,an increase in cement ratio results in a significant improvement in the dynamic characteristics of cement-improved loess;no optimal ratio of cement was noted.