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摘要: 本文以北川王家岩南侧沈家包抗滑桩加固工程为背景,通过现场低应变测试、混凝土强度测试、FLAC3D数值模拟及拟静力理论计算,系统研究了强震作用下抗滑桩加固边坡的动力响应规律。结果表明:(1)低应变反射波检测显示桩身完整,结合数值模拟验证,抗滑桩在汶川地震(峰值加速度1.0g)作用下未发生破坏;(2)边坡动力响应特征显著,坡面及竖向测线的峰值加速度(PGA)放大系数随坡高增加而增大,但抗滑桩可抑制PGA放大效应,未支护边坡坡脚最大水平位移达0.97 m,支护后降幅达89%;(3)抗滑桩内力分布特征显示,桩身剪力与弯矩峰值位于滑面附近,地震作用下桩顶位移9.78 cm满足规范容许限值;(4)参数敏感性分析表明,桩长16 m、间距6.75 m为最优抗震设计参数;(5)拟静力法与数值模拟结果趋势一致,但前者计算的桩身剪力与弯矩分别偏低2.93%和5.87%,建议抗震设计时安全系数取1.2以上。研究揭示了抗滑桩在强震作用下的动力响应机理,为高烈度区边坡抗震设计提供了理论与技术支撑。
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Abstract: This paper, based on the reinforcement project of anti-slide piles at Shenjiabao on the south side of Wangjiayan in Beichuan, systematically investigates the dynamic response patterns of slope reinforcement with anti-slide piles under strong seismic action through on-site low-strain testing, concrete strength testing, FLAC3D numerical simulation, and pseudo-static theoretical calculations. The results indicate: (1) Low-strain reflection wave detection shows the piles are intact, and numerical simulation verifies that the anti-slide piles did not fail under the Wenchuan earthquake (peak acceleration of 1.0g); (2) The slope's dynamic response characteristics are significant, with the peak ground acceleration (PGA) amplification factors along the slope surface and vertical measurement lines increasing with slope height, but the anti-slide piles can inhibit the PGA amplification effect. The maximum horizontal displacement at the toe of the unsupported slope reached 0.97 m, which was reduced by 89% after reinforcement; (3) The internal force distribution characteristics of the anti-slide piles show that the peak shear force and bending moment of the pile are located near the sliding surface, and the pile top displacement9.78 cm under seismic action meets the allowable limit specified by the code; (4) Parameter sensitivity analysis shows that a pile length of 16 m and a spacing of 6.75 m are the optimal seismic design parameters; (5) The pseudo-static method and numerical simulation results are consistent in trend, but the former calculates the pile's shear force and bending moment to be 2.93% and 5.87% lower, respectively, suggesting a safety factor of more than 1.2 for seismic design. The study reveals the dynamic response mechanism of anti-slide piles under strong seismic action, providing theoretical and technical support for seismic design of slopes in high-intensity areas. -

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