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基于极限分析上限定理,假定破坏面为任意滑动面,提出了一种用于评价加筋土石坝坡抗震稳定性的方法。该方法将素土和筋材的内能耗散率分开考虑,计算各滑动土条的外力功率与内能耗散率,并通过功能平衡条件,利用优化算法确定加筋土石坝的极限抗震能力,所得解物理意义明确、理论基础严格,能够很好反映加筋后土石坝处于极限状态时抗震能力的提高。通过一简单均质加筋边坡的算例分析,结果表明,该方法所得与已有研究成果有较好的一致性,且当水平条分数增加到一定数量时,解答趋于稳定,确定的任意滑动面能够很好地模拟加筋结构临界失稳时的破坏面。同时,通过对坝坡滑动体的水平条分,克服了以往竖向条分对拟静力地震荷载计算不精确的问题。应用该方法对一典型加筋心墙土石坝进行坝坡稳定分析。计算结果表明,坝坡加筋后,土石坝的抗震稳定性有了明显提高,其极限抗震能力较未加筋时提高了19%~21%,且加筋长度对土石坝的极限抗震能力有较大的影响。在实际工程中建议进行合理的计算分析以确定最佳加筋长度,对于本算例,最佳的加筋长度为30~40m。
Based on the upper bound theorem of limit analysis, a method of evaluating the seismic stability of reinforced rockfill dam slopes is proposed based on the assumption that the failure surface is an arbitrary sliding surface. In this method, the internal energy dissipation rate of plain soil and tendon is considered separately, the external force power and internal energy dissipation rate of each soil slip are calculated, and the optimal anti-seismic capacity of the reinforced earth-rock dam is determined by the function of equilibrium condition , The physical meaning of the obtained solution is clear and the theoretical basis is rigorous, which can well reflect the improvement of the seismic resistance of the earth-rockfill dam under extreme conditions. The results of an example analysis of a simple homogeneous stiffened slope show that the proposed method is in good agreement with the existing research results and the solution tends to be stable when the horizontal bar fraction increases to a certain extent Any sliding surface can well simulate the failure surface of the reinforced structure with critical instability. At the same time, the problem of inaccurate calculation of quasi-static earthquake load is overcome by the previous vertical slice through the horizontal slice of slider body. This method is applied to the stability analysis of dam slope of a typical reinforced earth wall dam. The calculated results show that the seismic stability of earth-rock dam has been significantly improved after the dam slope is reinforced, and the ultimate seismic capacity has been increased by 19% -21% compared with that without reinforcement. The ultimate seismic capacity of the earth-rock dam with the reinforcement length Greater impact. In practical engineering, it is suggested to make reasonable calculation and analysis to determine the optimal reinforcement length. For this example, the optimal reinforcement length is 30 ~ 40m.