循环预剪作用对饱和松砂抗液化强度影响  

Effect of cyclic preloading on resistance to liquefaction of saturated loose sand

作　　者：张振东[1,2,3] 栾茂田[1,2] 金丹[1,2,4] 郭莹[1,2] 

机构地区：[1]大连理工大学海岸和近海工程国家重点实验室,辽宁大连116024 [2]大连理工大学土木水利学院岩土工程研究所,辽宁大连116024 [3]淮海工学院土木工程学院,江苏连云港222005 [4]沈阳农业大学工程学院,辽宁沈阳110161

出　　处：《大连理工大学学报》2010年第1期111-116,共6页Journal of Dalian University of Technology

基　　金：国家自然科学基金资助项目(50579006;重点项目50639010)

摘　　要：利用土工静力-动力液压三轴-扭转多功能剪切仪,在均等固结条件下,针对福建标准砂(Dr=30%),进行了不同应力幅值的循环预剪试验和二次加载液化试验,探讨了波浪荷载的循环预剪作用对饱和砂土抗液化强度的影响.试验结果表明:循环预剪作用降低了饱和砂土孔隙比,但其影响程度较小.在较小的应力幅值范围和一定的循环次数内,循环预剪作用过程中所产生的最大孔隙水压力随着所施加的循环应力幅值的增加而呈线性的增长.在循环预剪过程中饱和砂土未发生液化条件下,随着循环预剪应力幅值的增加,饱和砂土的抗液化强度也不断得到提高.分析其原因,主要是在施加循环预剪作用时,饱和砂土孔隙的均匀化过程和砂土颗粒间咬合作用的增强,使砂土形成了较为稳定的结构.A series of tests were performed, including the cyclic preloadin magnitudes and the second loading liquefaction tests on Fujian saturated g lo tests with different stress ose sands with a relative density of 30% under isotropic consolidation condition by using the soil static and dynamic universal triaxial and torsional shear apparatus. And the effect of the cyclic preloading on the resistance to liquefaction of saturated loose sands was investigated. Experimental data indicate that the void ratio of saturated sands has a negligible reduction after cyclic preloading. And in the given cyclic numbers the maximal pore water pressure during the cyclic preloading increases linearly with the increment of cyclic stress magnitude which is small. Moreover, with the increment of the cyclic preloading stress magnitude, the resistance to liquefaction of saturated sands in the second loading is increased continuously under the condition that the liquefaction does not occur during the cyclic preloading. The reason is that more stable structure is constructed because of the uniformity of the void and the better interlocking of the particles when the cyclic preloading is performed on the saturated sands.

关 键 词：饱和砂土 液化 孔隙比 循环预剪 二次加载 

分 类 号：TU432[建筑科学—岩土工程]