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郑刚, 雷亚伟, 程雪松, 李溪源, 王若展. 局部锚杆失效对桩锚基坑支护体系的影响及其机理研究[J]. 岩土工程学报, 2020, 42(3): 421-429. DOI: 10.11779/CJGE202003003
引用本文: 郑刚, 雷亚伟, 程雪松, 李溪源, 王若展. 局部锚杆失效对桩锚基坑支护体系的影响及其机理研究[J]. 岩土工程学报, 2020, 42(3): 421-429. DOI: 10.11779/CJGE202003003
ZHENG Gang, LEI Ya-wei, CHENG Xue-song, LI Xi-yuan, WANG Ruo-zhan. Influences and mechanisms of anchor failure on anchored pile retaining system of deep excavations[J]. Chinese Journal of Geotechnical Engineering, 2020, 42(3): 421-429. DOI: 10.11779/CJGE202003003
Citation: ZHENG Gang, LEI Ya-wei, CHENG Xue-song, LI Xi-yuan, WANG Ruo-zhan. Influences and mechanisms of anchor failure on anchored pile retaining system of deep excavations[J]. Chinese Journal of Geotechnical Engineering, 2020, 42(3): 421-429. DOI: 10.11779/CJGE202003003

局部锚杆失效对桩锚基坑支护体系的影响及其机理研究

Influences and mechanisms of anchor failure on anchored pile retaining system of deep excavations

  • 摘要: 桩锚支护基坑中由锚杆失效引起的坍塌事故屡见不鲜。针对此问题,采用有限差分法研究了局部锚杆失效引发的土压力和支护结构内力变化等荷载传递规律,并利用大型模型试验加以定性验证。锚杆失效会导致邻近3~4根锚杆轴力显著增大,导致冠梁最大剪力和弯矩增加,冠梁按照构造配筋很容易发生破坏。随着锚杆失效数量的增加,锚杆最大荷载(轴力)传递系数逐渐增大并趋于定值,破坏范围内支护桩桩身变形和受力模式逐渐由支撑式向悬臂式过渡,最大弯矩先减小后增至定值,此时其荷载(弯矩)传递系数普遍大于锚杆。可见,锚杆失效较少时,破坏沿锚杆传递,失效较多时,破坏发展至支护桩。此外,开挖深度越大,土体强度越低,支护桩及锚杆荷载传递系数越高。

     

    Abstract: Collapse accidents of excavations caused by anchor failure are common in anchored pile retaining excavations. Aiming at the problem, the finite difference method (FDM) is adopted to study the rules of load transfer, such as the earth pressure and the internal force of retaining structures of local anchor failure, and the corresponding model tests are designed. Failure of anchors will lead to obvious increase of axial force of adjacent 3~4 anchors, increase of the maximum shear force and bending moment of capping beams, and easy damage of capping beams according to structural reinforcement. As the number of failed anchors increases, the maximum load transfer coefficient (It) increases gradually and tends to be a constant value, and the deformation and stress mode of piles gradually transform from braced type to cantilever one. The maximum bending moment first decreases, then increases to a constant value. Meanwhile, Im is generally larger than It. When the number of failed anchors is less, the failure will transmit along the anchor. When the number of failed anchors is more, the failure will develop to the pile. In addition, the larger the excavation depth, the lower the soil strength, and the higher the load transfer coefficient (Im and It).

     

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