摘要
沉井加桩基础作为深水地区大型桥梁常用的基础形式,其稳定性直接关系到桥梁的安全。为分析砂土中水平循环加载条件下冲刷对基础水平承载力和滞回圈刚度的影响,本文对沉井加桩复合基础进行了冲刷条件下的静载和循环后静载模型试验,得到了基础的水平荷载位移曲线和循环滞回圈。试验结果表明:冲刷对沉井加桩复合基础的水平承载力削弱严重。试验在中密砂、低围压条件下,循环加载会提高基础的水平承载力。对比循环后的静载曲线得知,无冲刷条件下的循环后基础水平承载力高于有冲刷条件下的该值。比较循环加载中的荷载位移曲线得到,无冲刷时滞回圈水平刚度高于有冲刷时的水平刚度,随着循环荷载次数的增加,滞回圈的水平刚度有所提高,但趋势减缓,并逐步稳定。
As the common foundation of the large bridge in deep water area, the stability of caisson-piles composite foundation is directly related to the safety of the bridge. To investigate the influences of scouring on the lateral bearing capacity and the horizontal stiffness of hysteresis loop of the composite foundation in sand under cyclic loading, the static loading test and post-cyclic test were carried out for the caisson-piles composite foundation. Finally, lateral load-displacement curves and cyclic hysteresis loops were obtained from the test. The test results show that scouring obviously reduces the lateral loading capacity of the foundation. For the current sand with intermediate density and low confining pressure, cyclic loading can increase the lateral loading capacity of the foundation. By comparing the post-cyclic load-displacement curves, the lateral bearing capacity under scouring is less than that free of scour. For cyclic Curves, the horizontal stiffness of hysteresis loop under scouring is less than that free of scour, which grows slowly with increased cyclic number, and gradually becomes stabilized.
出处
《地下空间与工程学报》
CSCD
北大核心
2017年第3期619-623,636,共6页
Chinese Journal of Underground Space and Engineering
基金
国家973计划课题(2013CB036304)
国家自然科学基金(51378392)
关键词
模型试验
冲刷
水平循环加载
沉井加桩复合基础
砂土
model test
scour
cyclic lateral loading
caisson-piles composite foundation
sand
