摘要
通过对2种洁净的干砂与饱和砂进行弯曲元与共振柱对比试验研究，得出了可靠的弯曲元剪切波传播时间确定方法，并对饱和砂土弯曲元与共振柱试验结果的偏差进行解释。不同频率激发信号对弯曲元剪切波速传播时间的研究证实，剪切波速随激发频率的增大而增大，采用激发频率为10kHz的初达波法与共振柱试验得到的结果具有较好的一致性。饱和砂土弯曲元与共振柱试验剪切波速结果相差6％～10％，可通过饱和砂土中剪切波速的弥散性对其进行解释。大部分洁净砂在弯曲元试验中激发频率一般大于特征频率，均需考虑剪切波速的弥散性。而对于天然砂土或粉土一般具有较高的特征频率，其弯曲元试验中一般不考虑剪切波速的弥散性。为洁净砂和天然砂土饱和土样的弯曲元测试提供有效方法。
The bender element （BE） and resonant column （RC） tests on two clean sands with various densities and mean effective stresses under dry and saturated conditions are performed. Based on the test results, a reliable method for determining the travel time in BE tests is evaluated. Also, the deviation of the shear wave velocity between BE and RC tests is explained. The studies on the effect of different excitation signals on shear-wave velocity indicate that the shear-wave velocity by the Start-Start method shows a slight increasing trend with an increase in the excitation frequency. The shear-wave velocity determined by the Start-Start method under the excitation frequency of l0 kHz is consistent with that from the RC tests. The shear-wave velocity values from the BE tests are about 6%-10% greater than those of the RC tests. The differences can be explained by the dispersion of shear wave under saturated conditions. This study suggests that the dispersion of shear wave should be considered in saturated clean sand because the excitation frequency of BE tests is greater than the characteristic one. However, the dispersion of shear wave should not be considered in the saturated natural sand or silt for the reason that the excitation frequency of BE tests is lower than the characteristic one. The results of this study provide effective methods for the BE tests on clean and natural sands under saturated conditions.
出处
《岩土工程学报》
EI
CAS
CSCD
北大核心
2013年第12期2283-2289,共7页
Chinese Journal of Geotechnical Engineering
基金
国家自然科学基金项目(51278383
51238009
51025827
51278779
51108414
51308420)
国家重点基础研究发展计划(973计划)项目(2011CB411907)
浙江省自然科学基金项目(Y1110751)
关键词
小应变剪切模量
饱和砂
剪切波速弥散性
弯曲元
共振柱
small-strain shear modulus
saturated sand
dispersion of shear wave
bender element
resonant column
