点安全系数与后缘裂缝协同控制的抗滑桩桩位选择

    PILE POSITION SELECTION OF ANTI-SLIDE PILE WITH SYNERGISTIC CONTROL OF POINT SAFETY FACTOR AND TRAILING EDGE CRACK

    • 摘要: 抗滑桩是岩土工程中治理滑坡最有效的手段之一,桩位选择主要依靠滑坡滑动机理定性确定,滑坡推力则主要通过条间剩余推力定量计算。为更好地统一抗滑桩桩位选择与滑坡推力计算,本文提出一种基于滑坡点安全系数解析计算结果的桩位选择方法。计算得到各条块点安全系数后,基于强度折减思想,以抗滑段点安全系数为1.0且剪出口条块所需支持力为0作为收敛标准,计算滑坡稳定性系数。利用条间力计算条块压缩量,并据此估算后缘裂缝宽度。融合点安全系数空间分布与后缘裂缝允许宽度构建双控指标体系,据此快速确定最优抗滑桩桩位,并以设计安全系数下相应桩位处的条间水平推力作为滑坡推力。通过ACADS标准考题验证,本方法计算的滑坡整体稳定性系数与传统方法(Fellenius法、Spencer法、Bishop Simple法)误差小于5%,具有良好的一致性。针对典型工程案例丹巴滑坡,利用PFC-FLAC耦合数值模拟验证了后缘裂缝估算方法的准确性;同时,本方法确定的抗滑桩桩位方案与工程实际采用的三维数值模拟设计结果高度吻合。研究表明:该方法不仅能够统一桩位选择与推力计算于同一力学框架,有效克服了传统经验方法的局限性,并在保证计算精度的前提下显著简化了设计流程。本方法为滑坡局部与整体稳定性协同评价及抗滑桩高效、可靠设计提供了有力的理论支撑和实用工具。

       

      Abstract: Anti-slide piles are among the most effective measures for landslide control in geotechnical engineering. The selection of pile position has traditionally relied on qualitative assessment of the landslide sliding mechanism, while landslide thrust is quantitatively calculated mainly through inter-slice residual thrust methods. To better integrate the selection of anti-slide pile location with the calculation of landslide thrust, this paper proposes a pile positioning method based on the analytical computation of the point safety factor across the landslide body. After calculating the safety factor at each point within sliding blocks, the overall stability coefficient of the landslide was determined using a strength reduction approach, with the convergence criterion set as a safety factor of 1.0 at the anti-sliding section and zero supporting force required at the shear outlet block. The inter-slice forces were used to estimate the compression within slices, and the width of the trailing edge crack was correspondingly estimated. A dual-control index system was established by combining the spatial distribution of point safety factors and the allowable width of the trailing edge crack, enabling rapid identification of the optimal anti-slide pile position. The horizontal thrust between slices at the selected pile position under the design safety factor was then taken as the landslide thrust. Validation against ACADS standard test problems showed that the error in the overall stability coefficient calculated by this method, compared with traditional methods (Fellenius, Spencer, and Bishop Simplified methods),was less than 5%,demonstrating good consistency. For the Danba landslide case study, the accuracy of the trailing edge crack estimation method was verified through PFC-FLAC coupled numerical simulation. Moreover, the anti-slide pile position determined by the proposed method aligned closely with the design results from 3D numerical simulations used in engineering practice. The results indicate that this method not only unifies pile positioning and thrust calculation within the same mechanical framework, effectively overcoming the limitations of traditional empirical approaches, but also significantly simplifies the design process while maintaining computational accuracy. This approach provides robust theoretical support and a practical tool for the collaborative evaluation of local and global landslide stability, as well as for the efficient and reliable design of anti-slide piles.

       

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