双向动荷载饱和粉土孔隙水压力研究

Study on the Pore Water Pressure of Saturated Silt in Two-directional Shock Test

地震引起的土体液化是导致地基失稳和上部结构受损的直接原因之一.利用美国GCTS空心圆柱扭剪仪,以天津地区海相可液化粉土为研究用土进行振动试验研究,对不同相位差的应力与孔隙水压力进行了分析,结果表明:双向动荷载不同相位差条件下动孔压增速不同,其中相位差为180°时孔压增长最快,相位差为0°和270°时孔压增长规律非常接近;土样在不同相位差双向动荷载作用下,相位差为180°时最先达到状态转换面,粉土振动最激烈、最先液化;围压、相位差对剪胀影响很小.

The silt liquefaction caused by the earthquake is one of the most important reasons of the foundation invalidation and the upper structure collapse. This paper utilized GCTS to conduct a vibration test to the liquefaction silt in Tianjin. The curves of stress and pore water pressure in different phase angles were analyzed. The result indicated that the speed of the dynamic pore water pressure in different of phase angles changed. When the phase angle is 180 degrees,the increase was the fastest to the pore water pressure,and the silt vibration had the most violent and liquefied firstly. Meanwhile,confining pressure and phase difference had little impact on the dilatancy.