The response of a buried pipe subjected to relative axial ground movement is investigated in this study using three-dimensional discrete element analysis. A discrete element model that is able to simulate the particulate nature of the granular material and the continuous nature of the pipe was developed. The micro-parameters of the model were calibrated using triaxial tests. The developed pipe–soil model was validated using experimental data and then used to calculate the pipe response to axial loading under varying soil conditions. A comparison was also made between the calculated response and the available closed-form solutions. Results indicated that, for pipes installed in dense sand, existing solutions may not properly account for the dilative behavior of the soil and hence underestimate the axial soil resistance. A parametric study was performed using the validated model to evaluate the factors controlling the axial soil resistance under these loading conditions. The contributing parameters are found to be the pipe diameter, burial depth, and soil properties. Results of the parametric study were used to develop an expression to estimate the earth pressure coefficient that reflects the dilative nature of the soil. An example is provided to illustrate the use of the proposed expression in estimating the maximum soil resistance to pullout loading.

中文翻译：

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估算轴向载荷条件下地下管道的土载荷：3D离散元分析的见解

在这项研究中，使用三维离散元分析研究了地下管道相对轴向地震动的响应。开发了能够模拟粒状材料的颗粒性质和管道连续性质的离散元素模型。使用三轴测试校准模型的微参数。使用实验数据验证了开发的管道-土壤模型，然后将其用于计算在不同土壤条件下管道对轴向载荷的响应。在计算的响应和可用的封闭形式解决方案之间也进行了比较。结果表明，对于安装在密实沙子中的管道，现有解决方案可能无法正确解释土壤的膨胀行为，因此低估了轴向土壤阻力。使用已验证的模型进行了参数研究，以评估在这些载荷条件下控制轴向土壤阻力的因素。发现主要的参数是管道直径，埋深和土壤特性。参数研究的结果用于开发一个表达式，以估计反映土壤膨胀性质的土压力系数。提供了一个示例来说明建议的表达式在估算最大抗拉拔土壤阻力方面的用途。参数研究的结果用于开发一个表达式，以估计反映土壤膨胀性质的土压力系数。提供了一个示例来说明建议的表达式在估算最大抗拉拔土壤阻力方面的用途。参数研究的结果用于开发一个表达式，以估计反映土壤膨胀性质的土压力系数。提供了一个示例来说明建议的表达式在估算最大抗拉拔土壤阻力方面的用途。