Combined Application of Optical Fibers and CRLD Bolts to Monitor Deformation of a Pit-in-Pit Foundation
Combined Application of Optical Fibers and CRLD Bolts to Monitor Deformation of a Pit-in-Pit Foundation
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DOI：
10.1155/2019/2572034
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发表时间：
2019-02
影响因子：
1.8
通讯作者：
Chun Zhu;Kai Zhang;H. Cai;Z. Tao;Bo An;M. He;Xing Xia;Jian-kang Liu
中科院分区：
文献类型：
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作者：
Chun Zhu;Kai Zhang;H. Cai;Z. Tao;Bo An;M. He;Xing Xia;Jian-kang Liu
“坑中坑”基础，其中整个坑分为内部和外部坑，提出了广泛的工程问题，但很少得到详细的研究。在影响深基坑稳定性的诸多因素中，荷载和降雨是两个最重要的因素。为此，本研究以我国典型工程应用的坑中坑基础为背景，在室内进行物理模型试验，模拟不同荷载和降雨流条件下体系的变形。采用光纤沿着与恒定电阻和大变形（CRLD）螺栓集中监测坑中坑基础内部的应力和应变，并辅以光纤布拉格光栅（FBG）位移计。监测结果表明，内坑相对于外坑的位置对外坑的稳定性有很大的影响。内坑最靠近外坑壁的一侧最容易不稳定，因此应予以加固。光纤和CRLD螺栓监测结果的比较和分析允许一个潜在的危险滑动面被识别，表明使用这种类型的集体监测深基坑的价值。
“Pit-in-pit” foundations, where the overall pit is divided into inner and outer pits, present a wide range of engineering problems and yet have received little detailed study. Among the many factors that affect the stability of a deep foundation pit, loading and rainfall are the two most important. Therefore, in this study, physical model experiments are carried out in the laboratory based on a pit-in-pit foundation that is typical of engineering applications in China, simulating the deformation of the system under different loading and rainfall flow conditions. Optical fibers along with constant resistance and large deformation (CRLD) bolts are adopted to collectively monitor the stress and strain inside the pit-in-pit foundation, assisted by fiber Bragg grating (FBG) displacement meters. The results of the monitoring show that the position of the inner pit relative to the outer pit has a strong influence on the stability of the outer pit. The side on which the inner pit is closest to the outer pit wall is the most prone to instability and should thus be reinforced. Comparison and analysis of monitoring results obtained with optical fibers and CRLD bolts allow a potentially dangerous slip surface to be identified, indicating the value of using this type of collective monitoring in deep foundation pits.