考虑土拱效应的边坡桩间土钉墙受力计算

边坡抗滑桩桩间土拱效应对桩间土钉墙各部分的受力及土钉的设计长度有重要影响，然而现阶段多依个人或者设计单位经验对桩间土钉墙各部分的受力进行计算，对土钉长度进行设计，以上传统的受力计算及土钉设计方法均未充分考虑土拱的影响，使得土拱在工程运用中受到了限制。为了推广土拱在工程中的运用，首先描述土拱形状，继而深入研究土拱对桩间土钉墙各部分受力的影响，提出了基于土拱效应桩间土钉墙受力计算方法和土钉长度设计方法，此受力计算方法认为：土钉墙的受力取拱前土体主动土压力或剩余下滑力两者中的较大者，抗滑桩的受力为拱后土体剩余下滑力与土钉墙受力之和，土钉长度设计中土钉自由段和锚固段的分界线为土拱迹线。继而结合巴（中）达（州）铁路堑坡，通过数值模拟描述土拱形状，计算土拱影响下不同截面处抗滑桩和土钉墙的受力，并结合土拱形状对土钉长度进行设计，与不考虑土拱效应时受力计算结果和土钉长度设计结果进行对比。研究结果表明：考虑土拱效应较不考虑土拱效应时，抗滑桩纵断面受力明显增大，增幅大于11%，土钉墙纵断面受力明显减小，减幅大于12%，土钉用量节省接近13%，充分说明考虑土拱效应确实对抗滑桩受力、土钉墙受力和土钉设计长度造成较大影响。

Load Calculation for Soil Nailing Wall Between Piles Basing on Soil Arching Effect

The soil arching effect between piles has an important effect on the force acting on various parts of a soil nailing wall between piles and the design length of the soil nails. However, at this stage, the force calculations on each part of the soil nailing wall between piles and the design length of the soil nail are often based on the experience of individuals or design units. The traditional force calculation and soil nail design methods do not fully consider the effect of soil arching, which limits soil arching in engineering applications. To promote the application of soil arching in engineering, this paper first describes the shape of soil arching and then studies the effect of soil arching on the force induced on various parts of the soil nailing wall between piles. Based on the soil arching effect, a force calculation method for the soil nailing wall between piles and a design method for soil nail length are proposed. The force calculation method considers that the force on the soil nailing wall is the greater force between active earth pressure before the soil arching and the residual sliding force before the soil arching. The force on the stabilizing pile is the sum of the residual sliding force due to the soil mass behind the soil arching and the force on the soil nailing wall. In the design of soil nail length, the boundary between the free section and the anchor section of the soil nail is the soil arching trace. Then, combined with the cut slope of the railroad in the Bazhong-Dazhou Railway, the shape of soil arching was determined through a numerical simulation, and under the effect of soil arching, the forces on the stabilizing piles and soil nailing walls at different cross-sections were calculated. The length of the soil nail was designed in combination with the shape of soil arching. The results of force calculations and soil nail design length were compared with the results before and after the consideration of the soil arching effect. The results indicate that compared to the case without considering the soil arching effect, when the soil arching effect is considered, the force on the vertical section of the stabilizing pile significantly increases by more than 11%. The force on the vertical section of the soil nailing wall significantly decreases by more than 12%, and the amount of material used in the soil nail reduces by approximately 13%. This clearly demonstrates that considering the soil arching effect does have a great impact on the force on the stabilizing pile, the force on the soil nailing wall, and the design length of the soil nail.