关键词: 敞口短管桩, 土塞效应, 静载试验, 桩端阻力, 工期和造价

Abstract: Combined with the analysis and comparison of foundation schemes for a 100 meter commercial and residential building in the northern suburbs of Xi'an, in view of the relatively thick and dense sand layer about 20m below the surface of the second terrace of the Weihe River, the open PHC short pipe pile foundation reinforcement method of hammer driven pile is selected by using the effect of soil plug at the pile end to improve the vertical compressive bearing capacity of the pile, which can successfully drive the pile and save the construction period and project cost. According to the comparative analysis of the static load test results, under the reasonable pile driving conditions, With the increase of pile top load, when the pile end is squeezed into the dense sand layer for about 5.0~6.0d, the soil plug effect of phc400 (AB) -95 open short pipe pile is strong, and the ultimate end resistance in the sand layer is significantly increased. It is proposed that when PHC open pipe pile takes the dense sand layer as the pile end bearing layer, the modified nominal equivalent ultimate end resistance under the soil plug effect can be considered, and the correction coefficient is 1.8~2.3. The observation results of building settlement are consistent with the previous analysis and prediction, which provides a reference for the foundation design of similar sites.