沉渣对冲击红层泥岩桩基承载特性影响研究

发布时间：2018-03-17 00:05

本文选题：红层泥岩　切入点：沉渣　出处：《地下空间与工程学报》2016年S2期 　论文类型：期刊论文

【摘要】：红层泥岩易崩解的特性致使桩底存在一定厚度的沉渣,沉渣的"软垫"效应等可能引起桩基承载力的下降。为了研究混凝土冲击作用下干孔沉渣和湿孔沉渣对红层泥岩桩基承载特性的影响,对红层泥岩地区某工程现场三根试桩进行静载试验,得到不同浇筑环境下的桩基lg Q-S曲线以及桩侧摩阻力随桩深变化关系曲线。根据试验结果分析了干孔、湿孔对桩基承载性能的影响,并利用有限差分软件进行数值模拟,验证现场试桩试验结果。结果表明:在沉渣厚度相同的条件下,桩孔(沉渣)为湿孔时,混凝土冲击作用明显(可能导致缩径),桩基的承载力较干孔有所提高,桩端阻力比干孔发挥的更充分;桩孔(沉渣)为干孔时,冲击效果不明显,孔底还残留较大厚度的沉渣,致使桩顶沉降(在相同的荷载下)明显较湿孔的大。
[Abstract]:The collapsibility of red mudstone leads to the existence of a certain thickness of sediment on the bottom of the pile. The "soft cushion" effect of sediment may cause the decrease of bearing capacity of pile foundation. In order to study the influence of dry-hole sediment and wet hole sediment on the bearing characteristics of red mudstone pile foundation under concrete impact, The static load test of three test piles in a project in red mudstone area was carried out, and the LG Q-S curve of pile foundation and the relationship curve of pile side friction with pile depth were obtained under different pouring environments. The dry holes were analyzed according to the test results. The effect of wet hole on the bearing capacity of pile foundation is simulated by finite difference software, and the results of field pile test are verified. The results show that when the thickness of sediment is the same, the pile hole (sediment) is wet hole. The impact effect of concrete is obvious (which may result in shrinkage of diameter, the bearing capacity of pile foundation is improved than that of dry hole, and the resistance of pile end is better than that of dry hole; when the pile hole (sediment) is dry hole, the impact effect is not obvious, and the sediment of large thickness remains at the bottom of the hole. The settlement of the pile top (under the same load) is obviously larger than that of the wet hole.
【作者单位】：西南石油大学土木工程与建筑学院;四川冶金建筑工程质量检测有限公司;
【基金】：国家自然科学基金(51574201) 四川省科技支撑计划项目(2014GZ0009) 住房和城乡建设部科技计划项目(2014-K3-037) 四川省科技创新苗子工程(2016119)
【分类号】：TU473.1

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