一、工程概况广贸大厦位于广汉市桂花街与西康路交汇处，基础采用人工挖孔灌注桩，即在地表下5．20m的地下室底板下采用一柱一桩，共布置44根桩，如图1，桩长6．30～6．90m，桩端扩大头直径为1800～3400mm。桩端土地基承载力设计值采用2800kPa。检查性的补勘表明，极端上为第四 I. Overview of the project Guangmao Tower is located at the intersection of Guihua Street and Xikang Road in Guanghan City. The foundation is made by manual digging and pouring piles, that is, under the floor of 5.20m under the ground, a pillar is used under the floor of the basement, and a total of 44 piles are arranged. In Fig. 1, the pile length is 6.30 to 6.90m, and the diameter of the enlarged pile head is 1800 to 3400mm. The design value of the bearing capacity of the pile foundation is 2800 kPa. Inspective supplementary survey shows that the extreme is fourth