摘要
文章以汶川震区中密饱和砂土为研究对象,利用DDS-70动力试验系统,进行振动频率f=1Hz时,固结比分别为K_c=1.0、K_c=1.5和K'_c=2.0条件下的固结不排水动三轴试验,分析了初始剪应力对汶川震区中密饱和砂土动力特性的影响,得出了如下结论:随着初始剪应力的增大,饱和砂土动孔压极值随之降低;在相同的围压和动应力作用下,随着初始剪应力的增大,饱和砂土动应变达到转折点所需的振次增大。在循环振次一定时,初始剪应力越大,其动强度越高;试样动强度均随着循环振次增加而降低的趋势,初始剪应力越大,降低的趋势越明显。
Taking the saturated medium dense sand in Wenchuan earthquake area as the research object, the undrained dynamic triaxial tests were conducted on the sand with Kc=1.0, 1.5 and 2.0 using DDS-70 Dynamic Experiment System when the vibration frequency was 1 Hz. The effects of initial shear stress on the dynamic properties of the saturated medium dense sand in the Wenchuan earthquake area were analyzed. The results are as follows： the critical dynamic pore pressure of the saturated sand decreases with the increase of the initial shear stress. Under the same confining pressure and dynamic stress, it will need more vibration times for saturated sand to reach the turning point of the dynamic strain if the initial shear stress grows. The initial shear stress has a positive effect on the dynamic strength if the cyclic vibration times keep constant. The dynamic strength decreases with the increase of cyclic time, and this trend is more obvious when the initial shear strength is higher.
出处
《水道港口》
2017年第3期299-303,共5页
Journal of Waterway and Harbor
关键词
汶川震区
饱和砂土
初始剪应力
动力特性
Wenchuan earthquake area
saturated sand
initial shear stress
dynamic characteristics
