重复荷载下模型支盘桩工程性状的试验研究

Project performance study of model piles with branches and plates under repeated load in silty clay

为研究在粉黏土中支盘桩在重复加载下的工程性状,在粉黏土中进行一次加载试验,测出其极限承载力,分别对一个双盘模型支盘桩在其极限荷载和0.75倍极限荷载的条件下各进行了5次重复加载卸载试验。根据试验结果,分析了在该土层中支盘桩的承载力和变形特性,研究了重复荷载作用下模型支盘桩在粉黏土中荷载传递的特点、桩身不同位置压力变化的特点,特别是对桩周土体对桩侧表面产生的摩擦力出现复杂变化的原因进行了分析,同时还分析了离盘不同距离的土体在重复加载过程中的压力变化情况和原因。研究结果表明,不同强度的荷载重复作用下对桩的沉降变形的收敛影响很大;支盘桩和桩周土体的相互作用机制十分复杂,因此要充分认识支盘桩在重复荷载作用下的工程性状和荷载传递机制还要做大量地研究。

The model pile with two plates was through 5 times repeated load-bearing and load-shedding tests under the limit load and 0.75 times of the limit load, in order to studying the project behavior of piles with plates and branches in silty clay. In addition, taking the simple loading test in silty clay for determining the limit bearing capacity. According to the test results, the bearing capacity and deformation characteristics of the pile in the soil are analyzed; and the pile＇s characteristics about load transfer in silty clay, characteristic of pressure changing on different places of pile are studied; especially the reason why the skin friction of the soil to the pile would appear complex changing is analyzed; in addition, the situation and reason of the pressure changing of soil different distances away from the plate during the repeated loading are analyzed too. It is shown that the repeated loading of different intensities loads impact obviously to the convergence of settlement deformation; the mutual effect mechanism of the pile and the soil is quite complex, so a lot of studies should be done to understand the project behavior and load transfer mechanism of the pile with plates and branches under repeated loading.