单桩承载力的一种直接动测法

A direct high-strain method for the bearing capacity of single piles

应用高应变动测法确定基桩的承载力非常依赖测试人员的经验且存在多解性问题。为克服这种现象,介绍了一种新的直接动测法,并以一灌注桩的现场静载试验为对象,建立了详细的基桩有限元静力、动力分析模型。静力模拟比较分析表明,该有限元模型能准确地模拟文献的结果。在此基础上,通过有限元动力分析,得到锤击下桩的应力场、位移场、速度场和加速度场。根据有限元计算结果,分析了直接动测法的有效性。直接动测法确定的承载力和静载法一致。该直接动测法消除了现有高应变法存在的多解性问题,故可以得到单桩承载力的客观性结果。

The application of current high-strain dynamic testing method to determine the bearing capacity of single piles depends on the experiences of the testing personnel, and the solution is not unique. To overcome these shortcomings, a new direct high-strain testing method is introduced in this paper. A finite element model is developed for a cast-in-place pile to analyze the effectiveness of the direct high-strain method for the bearing capacity of single piles. It is shown that the finite element model can accurately simulate the results in the published literature. By carrying out finite element dynamic analysis, the stress field, displacement field, velocity field and acceleration field of the pile for a hammer blow are obtained. According to the finite element calculation results, the bearing capacity is determined using the direct high-strain method. The bearing capacity determined by the direct high-strain method is consistent with that from static pile load test. The direct high-strain method eliminates the problem of multiple solutions in the existing high-strain method. Therefore, a unique bearing capacity of single piles can be obtained using the new direct high-strain testing method.