桩端采空区对嵌岩桩承载力的影响  

Influence of Goaf at Pile Tip on the Bearing Capacity of Rock-socketed Piles

作　　者：王开源 孙增奎[1] 沈宇鹏[2] 赵晓林 徐金翠 WANG Kai-yuan;SUN Zeng-kui;SHEN Yu-peng;ZHAO Xiao-lin;XU Jin-cui(CCCC Highway Consultants Co.,Ltd.,Beijing 100010,China;School of Civil Engineering,Beijing Jiaotong University,Beijing 100044,China)

机构地区：[1]中交公路规划设计院有限公司,北京100010 [2]北京交通大学土木建筑工程学院,北京100044

出　　处：《科学技术与工程》2024年第18期7821-7832,共12页Science Technology and Engineering

基　　金：中央高校基本科研业务费专项(KCJBZY23003536);国家自然科学基金(42172291)。

摘　　要：针对桩端采空区对嵌岩桩的设计(如承载性能和长期服役性能)提出的挑战,以杜家山特大桥采空区嵌岩桩为原型,进行缩尺模型试验,研究采空区到桩端不同距离以及采空区是否注浆的单桩承载力。计算比例参数,并选择合适的试验材料进行模型构建;通过多级荷载试验,获得采空区到桩端不同距离以及注浆后桩顶沉降、桩基础轴力、桩端阻力和桩侧摩阻力的变化特征;并对比分析了无采空区嵌岩桩的承载特征。结果表明,随着采空区到桩端距离的减小,桩端持力层的承载能力减小,不利于模型桩的承载力;注浆后,桩端持力层的承载能力明显增加,导致模型桩的桩顶沉降显著减少,承载能力显著提高。In view of the challenges posed by the goaf at the pile tip to the design of rock-socketed piles(such as load-bearing performance and long-term service performance),a scaled model test was conducted using the rock-socketed piles in the goaf of the Dujiashan Super Bridge as a prototype.A scaled model test was conducted to study the bearing capacity of single pile at different distances from the goaf to the pile tip and whether the goaf was grouted or not.The scaled parameters were calculated and appropriate test materials were selected for model construction.Through multi-level load tests,the changing characteristics of pile top settlement,pile axial force,pile tip resistance and pile side friction at different distances from the goaf to the pile tip and after grouting were obtained.And the bearing characteristics of rock-socketed piles without goaf were comparatively analyzed.The results show that as the distance from the goaf to the pile tip decreases,the bearing capacity of the model pile tip bearing layer decreases,which is not conducive to the bearing capacity of the model pile.After grouting,the bearing capacity of the pile tip bearing layer is significantly increased,resulting in a significant reduction in pile top settlement of the model pile and a significant increase in bearing capacity.

关 键 词：嵌岩桩 采空区 模型试验 桩顶沉降 桩基础轴力 桩端阻力 桩侧摩阻力 

分 类 号：TU473.1[建筑科学—结构工程]