永寿至咸阳高速公路咸阳机场立交静载试验

Experimental Research on Static Load of Xianyang Airport Overpass on Yongshou-Xianyang Expressway

结合永寿至咸阳高速公路咸阳机场立交试验区静载试验,研究了现场3根试桩浸水前后竖向受压的荷载传递性状,包括桩身轴力分布特征、桩侧摩阻力分布特征、桩侧摩阻力与桩端阻力的发挥性状以及极限承载力的确定,并对其进行了浸水前后对比分析。结果表明:试桩桩周分布的黄土湿陷性小,浸水后的轴力分布规律与浸水前大体一致。在同级荷载作用下,浸水后的桩侧最大摩阻力普遍比浸水前小。浸水后桩侧摩阻力的发挥比浸水前小,相应的浸水后桩端阻力发挥比浸水前大。另外,从桩端荷载所占总荷载的百分比看,试桩显示出摩擦桩的特性。从竖向极限承载力的确定分析出,浸水后单桩竖向极限承载力比浸水前均降低2级,并提出了相应的处理措施。

Based on static load test of Xianyang Airport Overpass on Yongshou-Xianyang Expressway, the determination of vertical compressive load transmission characters of 3 test piles before and after soaking was studied and compared. The characters include the distribution characters of axial force and skin friction, the display characters of skin friction and pile tip resistance, as well as the ultimate bearing capacity. The results show that （ 1 ） collapse settlement of the loess around test piles is small, the distribution character of axial force after soaking is similar to that before soaking ; （2） the maximum skin friction after soaking is smaller than that before soaking under the same load, the display character of skin friction after soaking is smaller than that before soaking, and the corresponding display character of pile tip resistance after soaking is greater than that before soaking; （3） from the pile tip resistance that accounts for percent of total load, test piles are friction pile. The determination of vertical ultimate bearing capacity shows that the vertical ultimate bearing capacity of single pile after soaking is two levels lower than that before soaking. The corresponding treatment measures were proposed.