用载荷试验及钢筋计测试联合确定一定深度上的桩基承载力

DETERMINING THE BEARING CAPACITY OF THE PILE BELOW A CERTAIN DEPTH BY THE METHOD COMBINING LOADING TEST AND STEEL BAR GAUGE MEASUREMENT

结合北京大使公寓工程桩基的测试,采用载荷试验和钢筋计的测试联合确定一定深度以下的桩基承载力的方法,对3根试验桩进行了测试。试验平面位于自然地表以下6 5m处,要求提供基础埋深-13 4m以下的有效桩长所具有的极限承载力。测试时,在桩体内主钢筋上预装了钢筋计,并测定了-6 5～-13 4m深度范围的桩侧摩阻力。从载荷试验中测定的-6 5m处桩基所具有的极限承载力中扣除上述桩侧摩阻力,可得到工程所要求的桩基极限承载力。实践证明,这是一种有效的测试方法。

In order to determine the bearing capacity of a pile under a certain depth,the skin friction of the pile between the top and the depth should be deducted from the bearing capacity of the pile on the top.The method combining static loading test and steel bar gauge measurement for the evaluation of the bearing capacity of a pile under a certain depth is introduced with a project case.Three piles in the project are tested.The test plane,ie.the top of the piles,where the test loads are applied to,is at the depth of -65m under surface ground.It is demanded that the test provides the bearing capacities of these three tested piles offered by the effective section below the depth of -134m.Several pairs of steel bar gauges are preinstalled to the main steel bars of the piles during the pile construction.During the loading test,the skin friction forces of the piles between the depth of -65m and -134m are measured and deducted from the bearing capacities measured by the loading test so that the wanted bearing capacities of the tested piles are obtained.The practical test proves that the method in this paper is efficient.