Evidence from recent earthquakes has shown destructive consequences of fault-induced permanent ground movement on structures. Such observations have increased the demand for improvements in the design of structures that are dramatically vulnerable to surface fault ruptures. In this study a novel connection between the raft and the piles is proposed to mitigate the hazards associated with a normal fault on pile-raft systems by means of 3D finite element (FE) modeling. Before embarking on the parametric study, the strain-softening constitutive law used for numerical modeling of the sand has been validated against centrifuge test results. The exact location of the fix-head and unconnected pile-raft systems relative to the outcropping fault rupture in the free-field is parametrically investigated, revealing different failure mechanisms. The performance of the proposed connection for protecting the pile-raft system against normal fault-induced deformations is assessed by comparing the geotechnical and structural responses of both types of foundation. The results indicate that the pocket connection can relatively reduce the cap rotation and horizontal and vertical displacements of the raft in most scenarios. The proposed connection decreases the bending moment response of the piles to their bending moment capacity, verging on a fault offset of 0.6 m at bedrock.

最近地震的证据表明，断层引起的永久性地面运动对结构造成了破坏性后果。这些观察结果增加了对极易受到表面断层破裂影响的结构设计改进的需求。在这项研究中，提出了一种筏板和桩之间的新颖连接，通过 3D 有限元 (FE) 建模来减轻与桩筏系统正常故障相关的危险。在开始参数化研究之前，用于沙子数值模拟的应变软化本构定律已根据离心机测试结果进行了验证。对固定头和未连接的桩筏系统相对于自由场中露头断层破裂的确切位置进行了参数研究，揭示了不同的失效机制。通过比较两种类型基础的岩土工程和结构响应，评估所提出的保护桩筏系统免受正常断层引起的变形的连接的性能。结果表明，在大多数情况下，袋式连接可以相对减少帽盖旋转以及筏板的水平和垂直位移。所提出的连接降低了桩对其弯矩能力的弯矩响应，基岩处的断层偏移量接近 0.6 m。