论文部分内容阅读
为研究单桩在抗拔与抗压条件下承载能力、桩身轴力以及侧摩阻力分布规律的不同,进行了砂土中长径比大于40的抗拔桩与抗压桩室内模型试验,通过桩身内设置电阻应变片,测得各级荷载下桩身不同深度的应变。分析表明,抗拔桩不论是位移还是位移增长速率,都远远超过抗压桩。因此,抗拔桩设计时应综合考虑桩顶上拔量来确定抗拔承载力。抗拔桩与抗压桩的桩身轴力分布具有相似的特性,试验所得抗拔总侧摩阻力折减系数λ=0.56。抗拔桩与抗压桩侧摩阻力都是从上部开始发挥并向下传递,随着荷载的增加,上部侧摩阻力变化很小,桩身中下部侧摩阻力迅速增长。抗拔桩桩端部侧摩阻力表现出弱化效应,抗压桩则表现出强化效应。
In order to study the bearing capacity of pile under tension and compression, the axial force of pile and the distribution law of lateral friction, the indoor model tests of uplift piles and compression piles with aspect ratio greater than 40 were carried out. Through the pile body set resistance strain gauge, measured at all levels of pile under different depth strain. The analysis shows that both the displacement and the displacement increase rate of the uplift piles far exceed that of the compression piles. Therefore, the anti-pull pile design should take into account the total amount of the top of the pile pull to determine the anti-pull bearing capacity. The axial force distribution of pile body has similar characteristics. The coefficient of friction reduction of the total pull-out side resistance is λ = 0.56. Both the anti-pile and the anti-pile side frictional force are exerted from the upper part and transmitted downward. With the increase of load, the frictional resistance of the upper part changes little and the frictional resistance of the middle and lower part of the pile increases rapidly. The frictional resistance at the tip of the uplift pile shows weakening effect, but the compression pile shows a strengthening effect.