强度折减动力分析法在滑坡抗滑桩抗震设计中的应用研究

利用动力有限差分软件FLAC,结合强度折减动力分析法,提出抗滑桩抗震设计新方法,将滑坡安全稳定系数作为岩土体参数折减系数对岩土体参数进行折减,采用FLAC动力分析,考虑了桩与岩土体地震荷载下动力相互作用,将地震作用过程中桩内力峰值除以混凝土强度增大系数与地震作用完毕之后桩的内力值进行比较,二者中大值作为桩的抗震设计内力值,同时还要求桩顶边坡动力安全系数大于设计容许值,确保滑坡不会发生越顶破坏。通过一个滑坡算例,对抗滑桩支护抗震设计进行分析,结果表明:动力强度折减分析法进行抗滑桩抗震设计,能考虑桩土动力相互作用,并得到实际桩前推力分布形式,为抗滑桩支护边坡的抗震设计提供了一个新的思路。

Study of application of strength reduction dynamic analysis method to aseismic design of anti-slide piles for landslide

Using dynamic finite difference software-FLAC, combining with strength reduction dynamic analysis method, a new method for anti-sliding pile aseismic design is proposed. Taking the security and stability factor of the landslide as a discount factor of rock mass parameters, then the rock mass parameters is discounted. Using FLAC dynamic analysis, soil-pile dynamic interaction is considered; the peak internal forces of piles engendered during the earthquake is divided by the coefficient of concrete strength increasing under earthquake, which compared with the internal forces of piles after the earthquake, the larger is considered to be the value of internal forces for aseismic design. While after the piles have been supported, the dynamic safety factor of the landslide should greater than the acceptable value to ensure the landslide would not damage over topping. An example of landslide with pile supported is given. The results show that the strength reduction dynamic analysis method is able to consider soil-pile dynamic interaction, and get the real distributed form of thrust force, so as to provide a new idea for aseismic design of anti-slide piles.